Contents
Petrofac E & C
WELDING INSPECTION HANDBOOK
Introduction Duties of the Welding Inspector Welder Qualifications Procedure Qualification Records Welding Consumables Pre-Heat and Post Heat Treatment Fabrication Welding Gases Welding Symbols Safety in Welding Conversion Tables & General Information
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Quality Department 1
Duties of the Welding Inspector Introduction This handbook has been prepared to provide PEC welding QC and construction personnel with a set of general inspection guidelines and technical information to ensure a consistent Quality of construction works on all E&C projects.
Received By: ………………………………….. Date: …………………………………………….
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It is the duty of the welding inspector to ensure that all operations concerning welding are carried out in accordance with written, approved procedures and specifications. The responsibilities of a welding inspector are given below: Read and interpret all applicable welding drawings and specifications. Check purchase orders to ensure that welding materials and consumables have been properly specified. Check and identify materials as they are received against the purchase specifications Check the chemical compositions and mechanical properties shown on mill test reports against specified requirements. Check storage condition of filler materials Check equipment being used (calibration status, visible condition...) Check weld joint preparations Verify the maintenance of welding parameters (current/voltage/heat input as applicable) at random. Check joint fit-up Verify application of approved welding procedure Verify qualifications of welders and welding operators Select production test samples as applicable Evaluate test results- Destructive & Non-Destructive Maintain records Prepare reports 3
Duties of the Welding Inspector Knowledge of drawings & specifications: • Advance study of drawings & specifications, construction in detail, MOC, welding procedure, heat treatment • Obtain necessary clarification/details from Design/Project engineer
Duties of the Welding Inspector Storage of filler material & welding equipment check: • Check storage conditions, e.g. Low Hydrogen Electrode baking / holding • Check welding machine type, its capability, calibration of ammeter, voltmeter Weld joint preparation:
This will help in: • Precise interpretation & decision during inspection • A Permitting or rejecting deviations observed • Decide feasibility of correcting error/deviation for large component • Determining specifications which are not defined. Material Verification:
• Check edge preparation for joint for: - Probable lamination - Bevel angle, root face - Preferable to have gauges • Cleanliness (free of oxidation, oil/grease) Qualification of Procedure & Welders:
• Advance study of drawings & specifications, construction in detail, MOC, welding procedure, heat treatment. • The specification for raw material e.g. ASTM A 106 Grade? • Consumable like electrode e.g. E 70 XX • Shielding gas, backing material • As far as possible ensure that original markings are preserved • Transfer identification marks before cutting, when required • Sometimes may be necessary to preserve electrode cases packets with original batch number.
• Establish written welding procedure specifications • Qualify procedures based on various WPS • Qualify welders based on various WPS • Verify records of validity • Interpret qualification ranges
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Duties of the Welding Inspector
Duties of the Welding Inspector Documentation
Inspection before Welding: Safety Ensure that all operations are carried out in compliance with local, company or National Safety regulations. If he sees unsafe practices he should stop the work and report the incident. Documentation • Read and understand the project specifications and relevant codes. If in doubt ask your superior. • Check that the correct revision of the drawing is used. • Check WPS’s and welder qualifications for approval. • Welding and related equipment has required calibration certificates, stickers. • Inspection instruments are calibrated as required. • Incoming materials, piping, fittings, welding consumables are the correct type and grade. They are stored correctly and have the required certification. • Material composition & condition of material • Type of edge preparation, method and finish
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• Consumable types i.e. electrodes, filler wires, fluxes, shielding and backing gases (composition) and special drying requirements for electrodes. • Welding processes • Cutting, Bevelling and Fit-up. • Check correct revision of drawing. • Heat no’s material and colour codes are transferred and recorded as required. • Correct method of cutting (pre-heat may be required prior to cutting). • Correct joint geometry as per the WPS. • Required pre-heat prior to tack welding. • Correct distortion precautions, number of tacks, jigs, line up clamps. • Qualified welder for tacking. Inspection during Welding: • Qualified welder for tacking. • Welding process • Weather conditions, is the weldment suitably protected from the elements. • Correct pre-heat and inter-pass application and maintenance. 7
Duties of the Welding Inspector Inspection during Welding: • • • • •
• •
• • •
Duties of the Welding Inspector Inspection after Welding:
Joint preparation Filler metals Control of distortion Qualified welder. Welding consumables are the correct type, not damaged and are stored correctly i.e. heated quivers or Vacuum packs. Welding and/or purging gas (type, flow rate, control method). In process inspection, welding parameters comply with WPS (volts, amps, travel speed, heat input for impact tested steels). Inter run cleaning, dedicated tools for corrosion resistant alloys. Maximum or minimum inter pass temperature, temperature and control method. Compliance with weld procedure sheet and applicable standard.
• Visual inspection of acceptable joint as per the appropriate specification. • Dimensional accuracy & conformity to drawings and specifications Inspection after Welding: • Weld is correctly numbered. • Welder(s) have marked the joint with his/there stamp numbers. • NDE as required (method, technician qualified, executed correctly) • Identify repairs from review of visual and NDE reports. • Repair area is marked correctly and welded with an approved welder and WPS. • Re-inspect after repair with visual and NDE. • Post weld heat treatment (PWHT), approved procedure. • Re-inspect with NDE after PWHT if required. • Collate reports and log the results.
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Duties of the Welding Inspector
Duties of the Welding Inspector
Summary of Weld Defects-Causes & Prevention
2- Porosity:
1- Cracks:
Causes:
Causes: • Hydrogen in the weld metal and/or heat affected zone introduced either through moisture in the welding consumable or shielding gas. Poor preparation of the base metal prior to welding, all rust, grease, mill scale should be removed and the weld preparation cleaned to bright sound metal. • Insufficient weld size. • High levels of joint restraint. • Poor joint design and/or preparation. • Rapid cooling rates. Prevention: • Make sure that consumables are correctly treated and stored. • Make sure the weldment is clean prior to welding. • Increase the weld size to part thickness. • Reduce joint restraint through proper design. • A more ductile weld metal may be required. • Slow down the cooling rate, by use of pre-heat and thermal insulation after welding. 10
• • • • • • •
Weldment is not cleaned correctly. Arc length is too long. Welding current is too high. Travel speed is too high. Loss of gas shielding. Damp or incorrectly treated electrodes. High solidification rate
Prevention: • Make sure the weldment is clean prior to welding. • Maintain proper arc length. • Use proper welding current for the size of consumable used, as specified on the WPS. • Reduce travel speed, as specified on the WPS. • Check the weldment is protected from wind and draughts. • Check shielding gas flow rate is in compliance with the WPS. • Check consumables are treated and stored required by an approved procedure. • Pre-heat or increase heat input to optimum
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Duties of the Welding Inspector
Duties of the Welding Inspector
3- Undercutting:
4- Lack of Fusion/Lack of root fusion:
Causes:
Causes:
• • • • • •
Amperage too high. Arc length is too long. Travel speed too high. Poor electrode manipulation. Inter pass temperature is too high. Arc blow with DC current.
Prevention: • Use proper welding current for the size of consumable used, as specified on the WPS. • Maintain proper arc length. • Reduce travel speed, as specified on the WPS. • Correct technique especially when weaving, qualified welder. • Use the max interpass temperature as specified on the WPS. • Make sure earth return lead is connected directly to the weldment.
• Travel speed to high • Amperage too low • Faulty joint preparation, root face too wide, root gap too small • Too large an electrode diameter • Loss of shield gas • Wrong electrode angle • Arc blow 11
Prevention: • Use correct travel speed as specified on the WPS. • Use proper welding current for the size of consumable used, as specified on the WPS. • Check joint geometry as specified on the WPS prior to welding. • Use the correct diameter electrode. • Check shield gas flow rate; make sure the welding area is protected from the elements. • Use proper technique and qualified welders. • Make sure earth return lead is connected directly to the weldment.
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Duties of the Welding Inspector
Duties of the Welding Inspector
5- Slag Inclusions:
6- Excess Penetration/Burn Through:
Causes:
Prevention:
• • • • •
Poor interpass cleaning. Excessive weaving. Erratic travel speed. Poor joint geometry. Uneven weld surfaces with sharp crevices
• Root gap as specified on the WPS • Root face as specified on the WPS • Correct amperage as per the WPS • Correct travel speed as per WPS • Welder training and qualification
Prevention: • • • • •
Proper cleaning methods between passes. Keep bead width to that specified on the WPS. Keep travel speeds in compliance with WPS. Make sure bevel angles are as specified on the WPS. Make the surface of smooth contour and grind uneven bead
6- Excess Penetration/Burn Through: Causes: • • • • •
Welder Qualifications Welder performance qualification tests are intended to determine the ability of welders and welding operators to make sound welds using an approved welding procedure. Required tests and ranges of qualification are dependent on the construction code used. Summarized below are the requirements of the two most commonly used Codes, ASME Section IX and API 1104. These requirements may be supplemented by additional project specification requirements.
Root gap too wide Root face too narrow Amperage too high Travel speed too low Poor technique 14
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ASME IX Welder Qualification Summary Essential Variables SMAW Para QW-402 Joints QW-403 Base Metal
QW-404 Filler Metal
QW-405 Positions
Essential Variables Manual & Semi Automatic GTAW Para
Brief of Variables -
.4
QW-402 Joints
Backing
.16
Change in Pipe Dia.
.18
Change in P-No.
.15
Change in F-No.
.30
QW-403 Base Metal
QW-404 Filler Metal
Brief of Variables
.16
Change in Pipe Dia.
.18
Change in P-No.
.14
+/- Filler
.15
Change in F-No.
.22
+/- Inserts
.23
Change from solid or metal cored to flux cored.
.30
Change of t weld deposit.
.1
+ Position
.3
Change
.8
- Inert Backing
.4
Change in Current or Polarity
Change in t weld deposits
.1
+ Position
.3
Change
QW-405 Positions QW-408 Gas QW-409 Electrical
- Backing
.4
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QW-452 Performance Qualification Thickness Limits & Test Specimens
QW-452 Performance Qualification Thickness Limits & Test Specimens
Type and Number of Examinations and Test Specimens Required
Side Bend QW462.2 Note 1
Face Bend QW462.3(a) or QW462.3(b) Notes 1 & 2
Root Bend QW462.3(a) or QW462.3(b) Notes 1 & 2
1
1
Note 3
Note 3
General Note: The “Thickness of weld metal is the total weld metal thickness deposited by all welders and all processes in the test coupon exclusive of the weld reinforcement.
Thickness of Weld Metal in (mm)
Visual Examination QW-302.4
Less than 3/8 (10)
X
3/8 (10) to less than ¾ (19)
X
2 Note 3
¾ (19) and over
X
2
• One face and root bend may be substituted for the two side bends.
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19
Notes: • To qualify using 5G or 6G, a total of four bend specimens are required. To qualify using a combination of 2G and 5G in a single test coupon, a total of six bend specimens are required. See QW-302.3. The type of bend test shall be based on the weld metal thickness. • Coupons tested by face and root bends shall be limited to weld deposits made by one welder with one or two processes or two welders with one process each. Weld deposit by each welder and each process shall be present on the convex surface of the appropriate bent specimen.
QW-452.1(b) Thickness of Weld Metal Qualified Thickness t of weld metal in the coupon, in (mm) Notes 1 & 2
Thickness of weld metal qualified Note 3
• Thickness of test coupon of ¾” (19mm) or over shall be used for qualifying a combination of three or more welders each of whom may use the same or a different welding process.
All
2t
QW-452.3 Groove Weld Diameter Limits
½ (13) and over with a maximum of three layers
Maximum to be welded
Notes: • When more than one welder and/or more than one process and more than one filler metal F-No is used to deposit weld metal in a coupon, the thickness t, of the weld metal in the coupon deposited by each welder with each process and each filler metal F-No in accordance with the applicable variables under QW-404 shall be determined and used individually in the: Thickness t of Weld Metal in the Coupon” column to determine the “Thickness of Weld Metal Qualified”.
Outside Diameter Qualified in (mm) Outside Diameter of Test Coupon in (mm)
Minimum
Maximum
Less than 1 (25)
Size Welded
Unlimited
1 (25) to 2 7/8 (73)
1 (25)
Unlimited
Over 2 7/8 (73)
2 7/8 (73)
Unlimited
General Notes:
• Two or more pipe test coupons with different weld metal thickness may be used to determine the weld metal thickness qualified and that thickness may be applied to production welds to the smallest diameter for which the welder is qualified in accordance with QW-452.3.
• Type and number of tests required shall be in accordance with QW-452.1 • 2 7/8 in (73) OD is equivalent of NPS 2 ½ (DN65). • Based on the above diameter limits a NPS 2” test coupon qualifies for a min diameter of NPS ¾”.
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QW-452.6 Fillet Qualification by Groove Weld Test
QW-452.5 Fillet Weld Test (Performance)
Type of Joint
Any Groove
Thickness of Test Coupon as Welded in (mm)
Qualified Range
Type and No. of Test Required
All
Fillet welds are qualified when a welder/operator qualifies on a groove weld test
All Thicknesses
Type of Joint
Thickness of Coupon as Welded in (mm)
3/16-3/8 (5-8) Tee Fillet Less than 3/16 (5)
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Qualified Range
All base material thicknesses, fillet sizes and diameters 2 7/8 (73) OD and over. Note 1 T to 2T base material thickness, T max fillet size and all diameters 2 7/8 (73) OD and over. Note1
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Type and Number of Test Required QW-462.4(b) or QW-462.4(c) Macro
Fracture
1
1
1
1
QW-452.5 Fillet Weld Test (Performance) General Note: • Production assembly mockups may be substituted in accordance with QW-181.2.1. When production assembly mockups are used, range qualified shall be limited to the fillet size, base metal thicknesses and configuration of the mockup. Note: • 2 7/8 in. (73mm) O.D. Is considered the equivalent of NPS 2 ½ (DN65). For smaller diameter qualifications, refer to QW-452.4 or QW-452.6. • ASME Section IX permits welders and welding operators to be qualified by radiography as an alternative to visual examination and mechanical testing, provided the following conditions are met.
QW-302.2 Radiographic Examination • When the welder or welding operator is qualified by radiographic examination, as permitted in QW-304 for welders and QW-305 for welding operators, the minimum length of coupon(s) to be examined shall be 6 inches (150mm) and shall include the entire weld circumference for pipe(s), except that for small diameter pipe, multiple coupons may be required, but the number need not exceed four consecutively made test coupons. The RT technique and acceptance criteria shall be in accordance with QW191. QW-304 Welders • Except for the special requirements of QW-380, each welder who welds under the rules of the Code shall have passed the mechanical and visual examination prescribed in QW-302.1 and QW-302.4 respectively. Alternatively welders making a groove weld using SMAW, SAW, GTAW, PAW and GMAW (except short circuiting mode) or a combination of these processes, may be qualified by radiographic examination, except for P21 through P25, P51 through P53 and P61 through P62 metals. Welders making groove welds in P21 through P25 and P51 through P53 metals with the GTAW process may also be qualified by radiographic examination. The radiographic examination shall be in accordance with QW-302.2.
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QW-321 Retests
QW321.3 Immediate Retest Using Radiography
• A welder or welding operator who fails one or more of the tests prescribed in QW-304 or QW-305, as applicable, may be retested under the following conditions.
• When the qualification coupon has failed the radiographic examination of QW-302.2 the immediate retest shall be by the radiographic examination method.
QW-321.1 Immediate Retest Using Visual Examination • When the qualification coupon has failed the visual examination of QW-302.4, retesting shall be by visual examination before conducting the mechanical testing. When an immediate retest is made, the welder or welding operator shall make two consecutive test coupons for each position which he has failed, all of which shall pass the visual examination requirements. The examiner may select one of the successful test coupons from each set of retest coupons which pass the visual examination for conducting the mechanical testing. QW-321.2 Immediate Retest Using Mechanical Testing • When the qualification coupon has failed the mechanical testing of QW-302.1, retesting shall be by mechanical testing. When an immediate retest is made, the welder or welding operator shall make two consecutive test coupons for each position he has failed, all of which shall pass the test requirements.
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• For welders and welding operators the retest shall be to radiographically examine two 6 inch (150mm) plate coupons; for pipe, to examine two pipes to a total 12 inch (300mm) of weld, which shall include the entire weld circumference for pipe or pipes (for small diameter pipe the total number of consecutively made test coupons may not exceed eight). QW-191.2 Radiographic Acceptance Criteria QW-191.2.1 Terminology A. Linear Indications. Cracks, incomplete fusion, inadequate penetration, and slag are represented on the radiograph as linear indications in which the length is more than three times the width. B. Rounded Indications. Porosity and inclusions such as slag or tungsten are represented on the radiograph as rounded indications with a length three times the width or less. These indications may be circular, elliptical, or irregular in shape; may have tails; and may vary in density.
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QW-191.2.2 Acceptance Standards
QW-191.2.2 Acceptance Standards
Welder and welding operator performance tests by radiography of welds in test assemblies shall be judged unacceptable when the radiograph exhibits any imperfections in excess of the limits specified below:
2) For welds in material less than 1⁄8 in. (3 mm) in thickness, the maximum number of acceptable rounded indications shall not exceed 12 in a 6 in. (150 mm) length of weld. A proportionately fewer number of rounded indications shall be permitted in welds less than 6 in. (150 mm) in length. 3) For welds in material 1⁄8 in. (3 mm) or greater in thickness, the charts in Appendix I represent the maximum acceptable types of rounded indications illustrated in typically clustered, assorted, and randomly dispersed configurations. Rounded indications less than 1⁄32 in. (0.8 mm) in maximum diameter shall not be considered in the radiographic acceptance tests of welders and welding operators in these ranges of material thicknesses.
A. Linear Indications (1) any type of crack or zone of incomplete fusion or penetration (2) any elongated slag inclusion which has a length greater than: (a) 1⁄8 in. (3 mm) for t up to 3⁄8 in. (10 mm), inclusive (b) 1⁄3t for t over 3⁄8 in. (10 mm) to 21⁄4 in. (57 mm), inclusive (c) 3⁄4 in. (19 mm) for t over 21⁄4 in. (57 mm) (3) any group of slag inclusions in line that have an aggregate length greater than t in a length of 12t, except when the distance between the successive imperfections exceeds 6L where L is the length of the longest imperfection in the group
API 1104 Welder Qualification Summary 6.2.2 Essential Variables For Welders
1) The maximum permissible dimension for rounded indications shall be 20% of t or 1⁄8 in. (3mm), whichever is smaller.
A change from one welding process to another welding process or combination of processes as follows: 1) A change from one welding process to a different welding process; or 2) A change in the combination of welding processes, unless the welder has qualified on separate qualification tests, using each of the welding processes that are to be used for the combination of welding processes.
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API 1104 Welder Qualification Summary 6.2.2 Essential Variables For Welders
API 1104 Welder Qualification Summary 6.2.2 Essential Variables For Welders
• A change in the direction of welding from vertical uphill to vertical downhill or vice versa. • A change of filler metal classification from Group 1 or 2 to Group 3, or from Group3 to Group 1 or 2. (See Table 1 API 1104). • A change from one outside diameter group to another. These groups are defined as follows:
• Change in the position from that which the welder has already qualified (for example a change from rolled to fixed or a change from horizontal to vertical of vice versa). A welder who successfully passes a butt weld qualification o test in the fixed position with the axis inclined 45 from the horizontal plane shall be qualified do butt welds and lap fillet welds in all positions.
1)Outside diameter less than 2.375 in. (60.3mm) 2)Outside diameter from 2.375 in. (60.3mm) through 12.750 in. (323.9mm) 3)Outside diameter greater than 12.750 in. (323.9mm) • A change from one wall thickness group to another. These groups are defined as follows:
Type and Number of Butt-Weld Test Specimens per Welder for Welder Qualification Test and Destructive Testing of Production Welds
B. Rounded Indications
For pipe less than or equal to 1.315 in. (33.4mm) in outside diameter, specimens from two welds or one full section tensile strength specimen shall be taken.
1) Nominal pipe wall thickness less than 0.188 in. (4.8mm) 2) Nominal pipe wall thickness from 0.188 in. (4.8mm) through 0.750 in. (19.1mm) 3) Nominal pipe wall thickness greater than 0.750 in. (19.1mm). • A change in the joint design (for example, the elimination of a backing strip or a change from V bevel to U bevel).
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Type and Number of Butt-Weld Test Specimens per Welder for Welder Qualification Test and Destructive Testing of Production Welds
Radiography-Butt Welds Only 6.6.1 General At the company’s option, the qualification butt weld may be examined by radiography in lieu of the tests specified in 6.5. 6.6.2 Inspection Requirements Radiographs shall be made of each of the test welds. The welder shall be disqualified if any of the test welds do not meet the requirements of 9.3. Radiographic inspection shall not be used for the purpose of locating sound areas or areas that contain imperfections and subsequently making tests of such areas to qualify or disqualify a welder. 6.7 Retesting If, in the mutual opinion of the company and the contractor’s representatives, a welder fails to pass the qualification test because of unavoidable conditions or conditions beyond his control, the welder may be given a second opportunity to qualify. No further retests shall be given until the welder has submitted proof of subsequent welder training that is acceptable to the company.
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ASME & EN Welding Positions
ASME & EN Welding Positions
Welding Positions For Groove welds
Welding Positions For Fillet welds
Welding Position
Test Position
ISO and EN
Welding Position
Test Position
ISO and EN
Flat
1G
PA
Flat (Weld flat joint at 45 degrees)
1F
PA
Horizontal
2G
PC
Horizontal
2F
PB
Vertical Upwards Progression
3G
PF
Horizontal Rotated
2FR
PB
Vertical Downwards Progression
3G
PG
Vertical Upwards Progression
3F
PF
Overhead
4G
PE
Vertical Downwards Progression
3F
PG
Pipe Fixed Horizontal
5G
PF
Overhead
4F
PD
Pipe Fixed @ 45 degrees Upwards
6G
HL045
Pipe Fixed Horizontal
5F
PF
Pipe Fixed @ 45 degrees Downwards
6G
JL045
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Welding Procedure Qualification Records Procedure qualification is extremely important with regard to consistent quality welding. The PQR forms the basis of the WPS which sets out detailed instructions to the welder who completes the joint. If the WPS is followed then welds produced using it should have the required mechanical properties required by the Construction Code. The inspector should take great care during the welding of PQR coupons to record all of the required non-essential, essential and supplementary essential variables. Welding variables below should be recorded using calibrated measuring instruments and should include: • • • • • • • • • • • •
Voltage Amperage/Polarity Travel Speed Heat Input Preheat Inter pass Temperatures Wire feed speeds Electrode stick out Bead sequence and layer thickness. Shielding/Purging gas types and flow rates Record the heat number of the base materials used Record the batch/lot numbers of the welding consumables used. • The stamp numbers of the welder(s) completing the coupon
• Record the heat number of the base materials used • Record the batch/lot numbers of the welding consumables used. • The stamp numbers of the welder(s) completing the coupon
Welding Procedure Qualification Records The Welding Data Sheet gives a guide to what information needs to be recorded. As well as the requirements of ASME IX newly qualified PQR documentation should also contain the following: • • • • •
Mill certificates of the base materials used. Consumable test certificates. NDE Reports. PWHT Charts if applicable. Laboratory mechanical test reports including macrograph photographs. • Laboratory reports of other tests conducted e.g. G48 pitting corrosion test, CTOD test reports, and ferrite count reports.
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PQR Welding Data Sheet
ASME IX QW-451 Procedure Qualification Thickness Limits and Test Specimens
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ASME IX QW-451 Procedure Qualification Thickness Limits and Test Specimens NOTES: 1)The following variables further restrict the limits shown in this table when they are referenced in QW-250 for the process under consideration: QW-403.9, QW-403.10, QW404.32, and QW-407.4. Also, QW-202.2, QW-202.3, and QW-202.4 provide exemptions that supersede the limits of this table. 2)For combination of welding procedures, see QW-200.4. 3)For the SMAW, SAW, GMAW, and GTAW welding processes only; otherwise per Note (1) or 2T,or 2t, whichever is applicable. 4)See QW-151.1, QW-151.2, and QW-151.3 for details on multiple specimens when coupon thicknesses are over 1 in. (25 mm). 5)Four side-bend tests may be substituted for the required face- and root-bend tests, when thickness T is 3⁄8 in. (10 mm) and over. # The thickness ranges above are further modified when impact testing is required see QW-403.6 below. They may also be restricted by the applicable construction Code e.g. B31.3
ASME IX QW-451 Procedure Qualification Thickness Limits and Test Specimens QW-403.6 The minimum base metal thickness qualified is the thickness of the test coupon T or 5⁄8 in. (16 mm), whichever is less. However, where T is less than 1⁄4 in.(6 mm), the minimum thickness qualified is 1⁄2T. This limitation does not apply when a WPS is qualified with a PWHT above the upper transformation temperature or when an austenitic material is solution annealed after welding. QW-451.3 Fillet Weld Tests (Procedure Qualification)
Type of Joint
Thickness of Test Coupon as Welded
Fillet
Per QW462.4(a)
Fillet
Per QW462.4(d)
Range Qualified
All fillet sizes on all base metal thicknesses and all diameters.
Type and Number of Tests Required (QW462.4(a) or QW-462.4(d) Macro 5
4
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QW-451.3 Fillet Weld Tests (Procedure Qualification)
API 1104 Type and Number of Tests Specimens for Procedure Qualification Test
General Note: A production assembly mockup may be substituted in accordance with QW-181.1.1. When a production assembly mockup is used, the range qualified shall be limited to the fillet weld size, base metal thickness, and configuration of the mockup. Alternatively, multiple production assembly mock-ups may be qualified. The range of thickness of the base metal qualified shall be no less than the thickness of the thinner member tested and no greater than the largest fillet weld tested. The configuration of production assemblies shall be the same as that used in the production assembly mockup.
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API 1104 Type and Number of Tests Specimens for Procedure Qualification Test • One nick-break and one root-bend specimen shall be taken from each of two test welds, or for pipe less than or equal to 1.315 inches (33.4 mm) • In diameter, one full-section tensile-strength specimen shall be taken. • For materials with specified minimum yield strengths greater than 42,000 psi (290 MPa), a minimum of one tensile test shall be required. The Ranges of diameters and thicknesses qualified are as follows: • Outside diameter less than 2.375 in. (60.3mm) • Outside diameter from 2.375 in. (60.3mm) through 12.750 in. (323.9mm) • Outside diameter greater than 12.750 in. (323.9mm) Range of thickness qualified: • Nominal pipe wall thickness less than 0.188 in. (4.8mm) • Nominal pipe wall thickness from 0.188 in. (4.8mm) through 0.750 in. (19.1mm) • Nominal pipe wall thickness greater than 0.750 in. (19.1mm).
API 1104 Material Groupings for Procedure Qualification: 5.4.2.2 Base Material: A change in base material constitutes an essential variable. When welding materials of two separate material groups, the procedure for the higher strength group shall be used. For the purposes of this standard, all materials shall be grouped as follows: 1) Specified minimum yield strength less than or equal to 42,000 psi (290 MPa). 2) Specified minimum yield strength greater than 42,000 psi (290 MPa) but less than 65,000 psi (448 MPa). 3) For materials with a specified minimum yield strength greater than or equal to 65,000 psi (448 MPa), each grade shall receive a separate qualification test. Note: The groupings specified in 5.4.2.2 do not imply that base materials or filler metals of different analyses within a group may be indiscriminately substituted for a material that was used in the qualification test without consideration of the compatibility of the base materials and filler metals from the standpoint of metallurgical and mechanical properties and requirements for pre- and post-heat treatment.
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ASME P Material Numbers
ASME P Material Numbers
This is a general guide for ASME P Numbers and their equivalent EN288 groupings. Groups referred to in the Base Metal column are ASME sub groups. EN288 material groups are included for comparison only. P No. EN288
P No.
EN288
5C
6
5 Sub Groups:- Chrome moly vanadium
6
8
6 Sub Groups:- Martensitic Stainless Steels Typically Grade 410
7
8
Ferritic Stainless Steels Typically Grade 409
Base Metal Carbon Manganese Steels, 4 Sub Groups
Base Metal
Austenitic Stainless Steels, 4 Sub groups 1
1
Group 1 up to approx 65 ksi Group 2 Approx 70ksi Group 3 Approx 80ksi Group 4 Approx 90ksi
2
-
Not Used
3
4
3 Sub Groups:- Typically half moly and half chrome half moly
4
5
2 Sub Groups: Typically one and a quarter chrome half moly
5A
5
Typically two and a quarter chrome one moly
5B
5
2 Sub Groups:- Typically five chrome half moly and nine chrome one moly
8
9
Group1 Typically Grades 304, 316, 347 Group 2 Typically Grades 309, 310 Group 3 High manganese grades Group 4 Typically 254 SMO type steels
9A, B, C
7
Typically two to four percent Nickel Steels
10A,B, C,F,G 10 H 10J
46
Mixed bag of low alloy steels, 10G 36 Nickel Steel 10
Duplex and Super Duplex Grades 31803, 32750 Typically 26 Chrome one moly
47
ASME P Material Numbers P No.
EN288
Base Metal
11A Group 1
7
9 Nickel Steels
11 A Groups 2 to 5
?
Mixed bag of high strength low alloy steels. 10 Sub Groups:- Mixed bag of high strength low alloy steels.
11B
ASME P Material Numbers P No.
EN288
Base Metal
34
Copper Nickel
35
Copper Aluminium
36 to 40
Not Used
41
Pure Nickel
42
Nickel Copper:- Monel 500
43
Nickel Chrome Ferrite:- Inconel
12 to 20
-
Not Used
44
Nickel Moly:- Hastelloy C22, C276
21
21
Pure Aluminium
45
Nickel Chrome :- Incoloy 800, 825
22
22a
Aluminium Magnesium Grade 5000
46
Nickel Chrome Silicone
23
23
Aluminium Magnesium Silicone Grade 6000
47
Nickel Chrome Tungstone
47 to 50
Not Used
24
-
Not Used
51, 52, 53
Titanium Alloys
22b
Aluminium Magnesium Manganese Typically 5083, 5086
61, 62
Zirconium Alloys
25 26 to 30
Not used
31
Pure Copper
32
Brass
33
Copper Silicone 48
49
Welding Consumables
Typical Baking & Holding Conditions for Covered Electrodes
• Handling control and thermal treatment plays a major role in the production of consistently high quality welds. • Prior to production welding a detailed Quality Control Procedure should be in place to give clear instructions on the receipt, storage, thermal treatment, issue and reconditioning of electrodes, solid wires and fluxes. • Check Points for the Inspector Include: 1)Documentation- Each lot or batch of consumables has a test certificate endorsed by the welding engineer. 2)Receiving Inspection- Packaging not damaged, consumable store is atmospherically controlled e.g. o Minimum temperature 20 C, and relative humidity is 60% maximum. The consumables are segregated by AWS specification; they are the correct size and specification as per the purchase order. 3)Thermal treatment for low hydrogen covered electrodes and SAW fluxes, is as per the manufacturers recommendations as is carried out in calibrated drying ovens. 4)Holding ovens and quivers are calibrated and are at the correct temperature. Electrodes are segregated by AWS specification and are not held in the same oven. 5)All consumables are issued against a written request which is available for inspection. 6)Unused consumables are returned to the store at the end of every shift. 7)Reconditioned (re-baked) electrodes are clearly identified. 50
51
Electrode Classification (SMAW Process)
SMAW Electrodes Position: 1) Flat, Horizontal, Vertical Overhead. 2) Flat and Horizontal Only. 3) Flat, horizontal, vertical down, Overhead. Type of coating and current: Digit
Type of Coating
Welding Current
0 1 2
Cellulose Sodium Cellulose Potassium Titania Sodium
DCEP AC, DCEP, DCEN AC, DCEN
3 Rut 4 5 Bsc 6 Bsc 7 8 Bsc
Titania Potassium Iron Powder Titania Low Hydrogen Sodium Low Hydrogen Potassium Iron Powder Iron Oxide Iron powder low Hydrogen
AC, DECP AC, DCEP, DCEN DCEP AC, DCEP AC, DCEP, DCEN AC, DCEP
E6020
Iron Oxide Sodium
AC, DCEP
52
53
SMAW Electrodes
SMAW Electrodes
Chemical composition of weld deposit:
Covered electrodes for SMAW welding have three types of flux covering: Cellulose (0, 1 designator) Deep penetration, fast freezing, light slag, needs care with undercutting. No baking they need moisture to operate correctly and therefore contains hydrogen. Rutile (3 designator) Smooth welding easy to use. Flat beads with easy slag removal, all position good general purpose electrodes. No baking required. Basic (5, 6 and 8 designator) Contain calcium carbonate and calcium fluoride which are basic elements, no cellulose. Excellent alloy transfer across the arc for good mechanical properties but usability can be difficult. Slag can be difficult to o remove. Bake at 350 C for 2 hours. Store in holding ovens at o o 150 C and heated quivers at 75 C minimum.
54
55
Solid Wires Classification Of Solid Wires:
Solid Wires Chemical composition of weld deposit:
56
57
Classification Of Wire / Flux Combination (SAW)
Classification Of Wire / Flux Combination (SAW) Typical examples of flux wire combinations: F7A5 – EM12K F 7 A 5 E M 12 K
Virgin (unused) flux Tensile strength of 70,000-95,000 psi Test done in the as welded condition Weld metal meets impact requirement of 20ft-lbf at o 50 F Solid wire electrode Medium manganese Chemical composition (see table below) F6P5 – EM12K
F 6 P 5
Virgin (unused) flux Tensile strength of 60,000-80,000 psi Test done in the post weld heat treated condition Weld metal meets impact requirement of 20ft-lbf at o 50 F Solid wire electrode Medium manganese Chemical composition (see table below)
E M 12 K # Note: • SAW flux needs to be dried before use, typically at 150°C +/- 20°C for 2 hours. Refer to the manufacturers handling and storage instructions. • A change in the wire flux combination is an essential variable and will require re-qualification of the welding procedure. 58
59
Chemical Composition Requirements for Solid Electrodes
List of AWS Classifications A5.1 A5.2 A5.3 A5.4 A5.5 A5.6 A5.7 A5.8 A5.9
A5.10 A5.11 A5.12 A5.13 A5.14 A5.15 A5.16 A5.17 A5.18
Carbon steel covered arc welding electrodes Iron & steel gas welding rods Aluminium and aluminium alloy arc welding electrodes Corrosion resistant chromium & Chromium nickel steel covered welding electrodes Low alloy steel covered welding electrodes Copper & copper alloy covered electrodes Copper & copper alloy welding rods Brazing filler metal Corrosion resistant chromium & chromium nickel bare and metal cored and standard arc welding electrodes and rods Aluminium & aluminium alloy welding rods & bare electrodes Nickel & nickel alloy covered welding electrodes Tungsten arc welding electrodes Surfacing welding rods & electrodes Nickel & nickel alloy bare welding rods Welding rods & covered electrodes for welding cast iron Titanium & titanium alloy bare Welding rods and electrodes Bare carbon steel electrodes and fluxes for sub arc welding Carbon steel filler metals for gas shielded arc welding
60
61
List of AWS Classifications
Pre-Heat & Post Weld Heat Treatment
A5.19 Magnesium alloy welding rods and bare electrodes A5.20 Carbon steel electrodes for flux Cored arc welding A5.21 Composite surfacing welding rods and electrodes A5.22 Flux cored corrosion resisting Chromium and chromium nickel Steel electrodes A5.23 Bare low alloy steel electrodes and fluxes for sub arc welding A5.24 Zirconium and zirconium alloy bare welding rods & electrodes A5.25 Electroslag welding of carbon and High strength low alloy steels A5.26 Electrogas welding of carbon and High strength low alloy steels A5.27 Copper gas welding rods. A5.28 Low alloy steel filler metals for Gas shielded arc welding A5.29 Low alloy steel flux cored Welding electrodes A5.30 Consumable inserts A5.31 Fluxes for brazing
62
Pre-Heating General: Pre-heating is used to slow down the cooling rate of the weldment and therefore prevent the formation of microstructures which are susceptible to cracking. Slow cooling will also allow hydrogen to diffuse out of the weldment and minimize the risk of hydrogen induced cold cracking. Pre-heating is done to: • Decrease the cooling rate of weld and base metal during welding • Eliminate the damp and moisture at the weld location, which are sources of hydrogen. • Reduce shrinkage stresses in highly restrained weld joints • Carbon Equivalent plays an important role in deciding preheating requirements. The weldability of Carbon steel is a dependent on Carbon equivalent • Higher the carbon equivalent lower the weldability • Carbon equivalent is calculated as per the below formula • CE = % C + ( % Mn )/6 + (%Cr + %M0 + %V)/5 + (%Ni +%Cu)/15 • As Carbon Equivalent value increases preheat requirement increases. CE > 0.38 requires preheating
63
Pre-Heating
Methods of Pre-heating:
• Preheating shall be in accordance with minimum WPS requirement • If preheating is required for welding then it is also required for arc air gouging • Oxy-acetylene should never be used for preheating • Oxy propane gas should be used. For pipes 24” dia and above electrical resistance mats are preferable • Heating band shall be a minimum of 150mm centered on the weld • Measurement of temperature should ideally be made on opposite side to welding • If same side heating, measurement should be taken after allowing 2minutes per 25mm thickness to allow for temperature equalization • Preheat should be applied and maintained around the full circumference of pipe to reduce stresses • If surfaces are wet then preheat should be used to dry them • Note that only one side of a joint may require preheat for dissimilar metal joints. • Additional preheat is often required during welding, depending on work size and local conditions.
1- Using heating torches 2- Electrical strip heating
3- Through Furnace heating 4- Induction or Radiation heating
Pre-Heating How is pre-heat temperature measured? 1- Using thermal crayons with specific temperature 2- Using digital thermometers • Reading shall be taken at least 75mm away from the point of welding arc • Care shall be taken to avoid weld contamination from Thermal crayons
64
65
ASME B31.3 (2008) Pre-Heat Temperatures Table 330.1.1 Preheat Temperatures(1)
ASME B31.3 (2008) Pre-Heat Temperatures Table 330.1.1 Preheat Temperatures(2)
Base metal PNo or S-No. Note1
1
3
Weld metal analysis A-No Note 2
1
3
5A, B & C
4, 5
6
6
Min. Temperature Require d oC
Recommend ed oC
mm
In.
MPa
ksi
<25
<1
490 and below
71 and below
10
25 & over All
1& over All
All
All
79
<1/2
>71 71 and below
79
<13
>490 490 and below
13 & over All
½& over All
All
All
79
>490
>71
79
All
All
All
All
149
2¼ % to 10% Cr
All
All
All
All
177
High Alloy Steel Martensitic
All
All
All
All
Alloy steel ½%Cr and below
Alloy Steel ½% to 2% Cr Alloy Steel
66
Specified Min. Tensile Strength, Base Metal
Base Metal Group
Carbon Steel
2, 11
4
Nominal Wall Thickness
67
10
149 Note 4
ASME B31.3 (2008) Pre-Heat Temperatures Table 330.1.1 Preheat Temperatures(3)
Nominal Wall Thickness
Base metal PNo or S-No. Note1
Weld metal analysis A-No Note 2
Base Metal Group
7
7
High Alloy Steel Ferritic
8,9
High Alloy Steel Austenitic
8
9A, B
Nickel Alloy Steel
10
Specified Min. Tensile Strength, Base Metal
Min. Temperature Require d oC
Recommend ed oC
mm
In.
MPa
ksi
All
All
All
All
10
All
All
All
All
10
All
All
All
All
93
All
All
All
All
10
Cr-Cu Steel
10I
27 Cr Steel
All
All
All
All
11A SG1
8 & 9 Ni Steels
All
All
All
All
11A SG2
5 Ni Steel
All
All
All
All
All
All
All
All
21-52
149204 149 Note 3 10 10
68
69
ASME B31.3 (2008) Pre-Heat Temperatures Table 330.1.1 Preheat Temperatures
Post Weld Heat Treatment
10
Prior to the start of any PWHT a detailed procedure should be in place to specify the specific requirements including:
Notes: 1) 2) 3) 4)
ASME B31.3 (2008) Pre-Heat Temperatures Table 330.1.1 Preheat Temperatures(4)
P-Number or S-Number from BPV Code Section IX A-Number from Section IX o Maintain interpass temperature between 177-232 C o Maximum interpass temperature 316 C Post Weld Heat Treatment
Post weld heat treatment (PWHT) is used to remove residual stresses form the weldment which is induced as a result of high thermal gradients (rapid heating and cooling) during welding. It is also used to control hardness values in the weld metal and heat affected zone.
1)Methods of PWHT e.g. local or furnace, electrical resistance or induction heating. 2)The type of chart recorders to be used. 3)The width of the heating band. 4)The width and thickness of insulation. 5)Heating rates, holding times and temperatures for different materials, controlled cooling. 6)The requirements of Thermocouples and their location during PWHT. 7)Hardness testing requirements after PWHT.
Typically PWHT is specified in construction Codes based on the thickness of the parts to be joined, requirements from ASME B31.3 are shown below, however different Codes may have different requirements. Project specific requirements may also have different requirements; in some cases carbon steels in NACE service will require PWHT regardless of size and thickness. The same may apply for low alloy steels P4 & P5A, B & C.
70
71
B31.3 Table 331.1.1 Requirements for Heat Treatment (1) Base Metal PNo or S-no Note1
Weld Metal Analysis ANo Note2
Base Metal Group
1
1
Carbon steel
3
2, 11
Alloy Steel Cr ½% and less
4 Note5
3
5A, 5B, 5C Note5
4, 5
Alloy Steels Above ½% up to 2% Cr Alloy Steels 2 1/4% up to 10% Cr 3% Cr and less, and 0.15% C and less 3% Cr and less, and 0.15% C and less Above 3% Cr or C above 0.15%
B31.3 Table 331.1.1 Requirements for Heat Treatment (2)
Nominal Wall Thickness mm.
Specified Min. Tensile strength Base metal Mpa
Metal Temperat ure Range oC
20 and less Above 20 20 and less Above 20 All 13 and less Above 13 All
All All 490 & Less All Above 490 490 and less All Above 490
None 593-649 None 593-718 593-718 None 704-746 704-746
All
None
All
All
13 and less
Holding Time Nominal Wall Min Note3 time hr Min/mm Hr/in
Brinell hardness max. Note4
2.4
1
1
2.4 2.4
1 1
1 1
225 225
2.4 2.4
1 1
2 2
225 225
704-760
2.4
1
2
241
704-760
2.4
1
2
241
Above 13 All
‘
72
73
B31.3 Table 331.1.1 Requirements for Heat Treatment (3)
B31.3 Table 331.1.1 Requirements for Heat Treatment (4)
Base Metal PNo or S-no Note1
Weld Metal Analysis ANo Note2
Base Metal Group
Nominal Wall Thickness mm.
Specified Min. Tensile strength Base metal Mpa
Metal Temperatu re Range o C
All
All
732-788
2.4
All
All
621-663
All
All
None
All
None
All All
None 593-635 760-816 Note6 None Note7 663-704 Note8 None 552-585 Note9 552-585 Note9
High Alloy Martensitic A240 Gr.429 High alloy steels ferritic High alloy steels austenitic Nickel alloy steels
20 and less Above 20
10
Cr-Cu Steels
All
10H
Duplex Stainless Steel
All
10I
27Cr Steel
All
6
6
7
7
8
8, 9
9A, 9B
10
All
All All 51 and less
11A SG1
8Ni & 9Ni steels
11A SG2
5Ni steel
Above 51
62
Zr R60705
All
Above 51
All All All All All
74
538-593
Holding Time Nominal Wall Note3
Min tim e hr
Brinell hardnes s max. Note4
1
2
241
2.4
1
2
241
1.2
1/2
1
1.2
1/2
1/2
1.2
1/2
1/2
2.4
1
1
2.4
1
1
2.4
1
1
Note10
Note10
1
Min/mm
75
Hr/in
B31.3 Table 331.1.1 Requirements for Heat Treatment
Typical Heating & Insulation Band Widths
NOTES: 1) P-Number or S-Number from BPV Code, Section IX, QW/QB-422. 2) A-Number from Section IX, QW-442. 3) For holding time in SI metric units, use min/mm (minutes per mm thickness). For U.S. units, use hr/in. thickness. 4) See Para. 331.1.7. 5) See Appendix F, Para. F331.1. 6) Cool as rapidly as possible after the hold period. 7) Postweld heat treatment is neither required nor prohibited, but any heat treatment applied shall be as required in the material specification. 8) Cooling rate to 649°C (1,200°F) shall be less than 56°C (100°F)/hr; thereafter, the cooling rate shall be fast enough to prevent embrittlement. 9) Cooling rate shall be > 167°C (300°F)/hr to 316°C (600°F). 10) Heat treatment within 14 days after welding. Hold time shall be increased by 1⁄2 hr for each 25 mm (1 in.) over 25 mm thickness. Cool to 427°C (800°F) at a rate ≤ 278°C (500°F)/hr, per 25 mm (1 in.) nominal thickness, 278°C (500°F)/hr max. Cool in still air from 427°C (800°F).
A = Minimum heating band with at PWHT temperature is the width of the weld plus 25mm either side of the weld. 2A = Minimum Insulation Band width.
77
76 Suggested Heating & Cooling Rates for P1 Materials
Fabrication o
Base Metal Thickness Heating & Cooling Rate C/hr o Range (mm) above 315 C Up to 25 200 25.1 to 30 165 30.1 to 35 140 35.1 to 40 125 40.1 to 45 110 45.1 to 50 100 50.1 to 55 90 55.1 to 60 80 o Heating/Cooling Rate ( C) = 5000/Thickness in mm o Maximum Heating/Cooling Rate = 200 C/hour Additional soaking time for thickness above 25mm will be 2.4minutes/1mm thickness.
ASME B31.3 Fig. 328.4.2 Typical Butt Weld End Preparation
78
79
Fig. 328.4.3 Trimming and Permitted Misalignment
Alignment Tolerances ASME Section 1 Table PW-33 Alignment Tolerance Of Sections To Be Buttwelded Direction of Joints in Cylindrical Shells Section Thickness, in. Up to 1⁄2, incl. Over 1⁄2 to 3⁄4, incl. Over 3⁄4 to 11⁄2, incl. Over 11⁄2 to 2, incl. Over 2
Longitudinal 1⁄4t 1⁄8 in. 1⁄8 in. 1⁄8 in. Lesser of 1⁄16t or 3⁄8 in.
Circumferential 1⁄4t 1⁄4t 3⁄16 in. 1⁄8t Lesser of 1⁄8t or 3⁄4 in.
Socket Welds Socket welds are highly susceptible to cracks and porosity if the correct welding procedure is not strictly adhered to: Prior to welding the socket fitting and the pipe shall be free from dirt, grease, paint or primer both internally and externally. The pipe end shall be square and free from burrs and grinding dust.
80
81
Fig. 328.5.2C Minimum Welding Dimensions for Socket Welding Components Other Than Flanges
Socket Welds 1- Insert the square prepared end of the pipe into the socket fitting. Socket Weld Fitting
Pipe
2- Push the pipe into the fitting until it stops. Scribe a line on the outside of the pipe. Correct fit up is achieved by pushing the pipe into the socket until there is no gap. A line is then scribed around the circumference of the pipe. The pipe is then pulled out to a minimum distance of 1.5mm before tack welding.
82
Line scribed on the pipe
83
Socket Welds
Socket Welds
3- Pull the pipe out to a distance of 2mm, check by steel rule.
Typical Welding Sequences
2 passes
3 passes
2mm • The GTAW process shall be used to complete the weld. Adequate protection from wind draughts shall be provided prior to any welding. A minimum of two passes is required to complete the weld; under no circumstances shall single pass welding be permitted. • Visual inspection to confirm that there are no pores open to the surface, the weld profile is convex and there is no undercut at the toes of the weld. Dye penetrant testing is the preferred method of NDT for socket welds in all materials. • The inspector may also call for spot RT to confirm the gap at the end of the pipe. Socket welds shall be unpainted during pressure testing. 84
85
Commonly Used Materials for Process Pipework (1)
Commonly Used Materials for Process Pipework (2)
ASTM A105
Forgings, Carbon Steel for Piping Components
ASTM A312
Seamless and Welded Austenitic Stainless Steel Pipe
ASTM A106
Seamless Carbon Steel Pipe for High Temperature Services
ASTM A320
Alloy Steel Bolting Materials for Low Temperature Service
ASTM A333
Seamless and Welded Steel Pipe for Low Temperature Service
ASTM A350
Forgings, Carbon and Low Alloy Steel, requiring Notch Toughness Test for Low temp components Steel Castings, Austenitic, for High Temperature Service
ASTM A182
ASTM A193
Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings and Valves and Parts for High temp. service High Temperature Service Alloy Steel and Stainless Steel Bolting materials for High Temperature Service
ASTM A194
Carbon and Alloy Steel Nuts for Bolts for High Pressure and High Temperature Service
ASTM A351
ASTM A216
Specifications for steel Castings, carbon suitable for Fusion welding for High-Temperature Service.
ASTM A352
ASTM A217
Specification for steel castings, Martensitic stainless and alloy for pressure containing parts, suitable for high temperature service
ASTM A358
ASTM A234
Piping Fittings of Wrought Carbon Steel and Alloy Steel for moderate and Elevated temp
ASTM A370
Standard test methods and definitions for mechanical testing of steel products
ASTM A403
Wrought Austenitic Stainless Steel Piping Fittings
ASTM A240
Heat Resisting Chromium and Chromium Nickel Stainless Steel Plate, Sheet and Strip for Fusion - Welded Unfired Pressure Vessels
86
Steel Castings Ferritic and Martens tic for Pressure Containing Parts Suitable for Low temp service Electric-Fusion-Welded Austenitic ChromiumNickel Alloy Steel Pipe for High-Temperature Service
87
Commonly Used Materials for Process Pipework (3) ASTM A420
ASTM A453 ASTM A515 ASTM A516 ASTM A671
ASTM A672 ASTM A790 ASTM A815 ASTM A890
Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low Temperature Service Specification for High temperature Bolting Materials, with expansion coefficient comparable to Austenitic stainless steels Carbon Steel Plate for Moderate and Higher, Temperature Service Carbon Steel Plate for Moderate and Lower, Temperature Service Standard Specification For Electric-FusionWelded Steel Pipe For Atmospheric And low temperatures Standard Specification For Electric-FusionWelded Steel Pipe For High Pressure Service at Moderate Temperature. Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe Wrought Ferritic, Ferritic/Austenitic, and Martensitic Stainless Steel Piping Fittings Castings, Iron-Chromium-Nickel-Molybdenum Corrosion- Resistant, Duplex (Austenitic/ Ferritic) for General Application
Commonly Used Materials for Process Pipework(4) ASTM A928
Electric-Fusion-Welded Austenitic/ Ferritic Steel Pipe
BS 1868
Specification for steel check valves for petroleum, petrochemicals and allied industries
BS 1873
Specification for Steel Globe and Globe stop and check valves
BS 4882
Specification for bolting for Flanges and pressure containing purposes
BS 6364
Specification for valves for cryogenic service
EN 10204
Metallic Products - Types of Inspection Documents
EN 12560
Flanges and their joints. Gaskets for class designated Flanges
89
88
Purging
Welding Gases There are a number of welding processes which use externally provided gases to protect the molten weld pool from the detrimental effects of the atmosphere, the most common are: 1- GTAW Gas Tungsten arc welding. Typical shielding gas is high purity Argon 99.995% For Duplex Argon + 1 to 3% Nitrogen may be used. 2- GMAW Gas Metal arc welding. Typical shielding gas Argon + 10 to 20% CO2 3- FCAW Flux Cored arc welding. Typical shielding gas Argon + 10 to 20% CO2 4- PAW Plasma arc welding. Typical shielding gas is high purity Argon 99.995% Purging • Purging is required for welding stainless steels CRA material to reduce internal oxidation and heat tint to industry norms. In general pure Argon is used for purging however in some cases Nitrogen is used. • Must be considered for the following cases: - Butt joints <6mm wall thickness. - Butt joints until 6mm deposition are completed.
90
- Repairs where parent material is <6mm thick. - Repairs where thickness after excavation <6mm. - Attachment welds where pipe thickness is <6mm. • The purge system shall be suitable for the operation and designed to avoid risk of internal damage or contamination to the bore of the pipe. • Purge time will vary for pipe size and purge volume Typical examples Pipe Dia inch 3-4 6-8 10 - 12 20 24 32
Flow Rate l/min 10 10 10 12 20 20
Vent Size mm 1.5 3 3 3 3 3
Purge Time min 3 6 13 25 30 40
• The pre-purge flow rate should be limited to a <20 l/min. If exceeded, purge times can actually increase due to turbulence and air mixing within the pipe. • Increased flow rates may cause turbulence and increase purge times.
91
Purging
Welding Symbols
• Flow rate/purge time should allow for at least five volume changes. • Sample oxygen using suitable calibrated purge monitor/indicator. Typical requirements are <0.5% for 300 grades, <0.02 - 0.05% for duplex and 0.05% for 6Mo.
Examples Fillet Weld Symbol
Desired Weld
Welding Symbols Fillet 6mm length
6mm
Fillet Welds Arrow Side
Other Side
ngth Both Sides
Single Bevel Arrow Side
Single Bevel Other Double Bevel
Groove Welds Arrow Side
Other Side
Both Side
92
93
Groove Weld Symbol
Parts & Sizes of Welds
94
95
Safety In Welding • Before starting actual arc welding the welder / welding operator should be fully aware of the dangers involved. The high temperature arc and hot metal can cause severe burns. In addition the electric arc itself provides an additional safety hazard. • The electric arc emits large amounts of ultra violet and infra-red rays. Both types of rays are invisible to the naked eye just as the same type of rays emitted by the sun is invisible. However they both have the identical properties of causing sunburn on the human skin, except that the arc burns much more rapidly and deeply. Since these rays are produced very close to the operator they can cause very severe burns to the eyes in a short exposure time. • When welding with the electric arc, there is added danger that the small globules or droplets of molten metal may leave the arc and fly in all directions. These so called sparks range in temperature from 2000 ° to 3000° Fahrenheit and in size from very small to as large as ¼ inch. They present a personal burn hazard plus a fire hazard if they fall in inflammable material. • The welding operator needs to protect himself, by means of a helmet and other protective devices from the harmful rays of the arc and flying sparks. The filter plates in the welding helmet will remove 99% of the harmful rays if the proper shade lens is used.
Safety In Welding Other dangers associated with electric arc welding are: 1- Electric shock-which may be caused by standing in damp areas, welding without gloves, bare cables, uninsulated holder, etc. 2- Harmful fumes given off in welding process especially when welding on galvanized or other coated materials. • The operator should be familiar with all safety precautions and take care to adequately protect himself at all times against any hazards associated with arc welding by wearing protective clothing and equipment, working in dry conditions, providing adequate ventilation and in general using good common sense. • Following is a list of safety precautions that should be observed in the use of the arc welding equipment: Electric Shock: 1) Make sure machine is properly grounded. 2) Never permit “live” parts of the electric welder to touch bare skin or wet clothing. 3) Do not cool electrode holders by emersion in water. 4) Turn off power supply when welder is not in use. 5) Do not stand on wet areas while welding.
96
97
Safety In Welding
Safety In Welding
Electric Shock:
Radiation Energy (Ultraviolet rays etc):
6) Wear leather gloves. 7) Make sure cable are covered and in good condition. 8) Make certain that electrode holders are properly insulated. Burns: 1) Protect eyes and face from flying particles of slag by use of safety glasses or face shield. 2) Wear adequate protective clothing. 3) Always wear leather gloves. 4) Wear high top shoes. 5) Keep collar, shirt pockets, etc buttoned. 6) Do not touch the electrode or metal where welding has taken place. 7) Handle hot metal with pliers or tongs. 8) Keep electrode stubs properly disposed of. Radiation Energy (Ultraviolet rays etc): 1) Use a welding helmet with the correct shade lens in good condition. 2) Wear suitable clothing—do not leave bare skin exposed to the rays of the arc.
98
3) Do not strike the arc without covering the face and eyes. Give warning to others before striking the arc. 4) Avoid looking directly at the arc where others are welding without proper eye protection. Gases & Fumes: 1) Work only in well-ventilated areas. 2) Use great care when working on metals covered with lead or zinc. 3) If working in a confined area use respirator or other approved breathing devices. Combustible Materials: 1) Keep shop clean in areas where welding is to be done. 2) Do not weld near combustible materials of any kind. 3) Never weld on covered containers which may have held combustible materials without first taking adequate safety precautions. For example, fill them with water, steam clean or fill with an inert gas.
99
Safety In Welding
Hardness Conversion Tables (2)
Fire Protection: 1) 2) 3) 4)
Be familiar with location and types of fire extinguishers. Report any unsafe conditions that might start a fire. Do not weld near inflammable materials. Do not weld on containers that have held inflammable materials. 5) Do not weld near electrical fittings or lines.
Hardness Conversion Tables (1) Hardness Conversion Table Brinell Tensile Vickers Hardnes Strength Hardness s 2) (N/mm (HV) (BHN)
Rockwell Hardness (HRB)
285
86
90
320
95
100
56.2
350
105
110
62.3
385
114
120
66.7
415
124
130
71.2
450
133
140
75.0
Rockwell Hardness (HRC)
Hardness Conversion Table Tensile Brinell Vickers Rockwell Strength Hardness Hardness Hardness 2) (N/mm (BHN) (HV) (HRB) 480
143
150
78.7
510
152
160
81.7
545
162
170
85.0
575
171
180
87.1
610
181
190
89.5
640
190
200
91.5
675
199
210
93.5
705
209
220
95.0
740
219
230
96.7
770
228
240
98.1
800
238
250
99.5
820
242
255
Rockwell Hardness (HRC)
23.1
100
101
Hardness Conversion Tables (3)
Metric / imperial conversion factor (1)
Hardness Conversion Table Tensile Brinell Vickers Rockwell Strength Hardness Hardness Hardness 2) (N/mm (BHN) (HV) (HRB)
Rockwell Hardness (HRC)
850
252
265
24.8
880
261
275
26.4
900
266
280
27.1
930
276
290
28.5
950
280
295
29.2
995
295
310
31.0
1030
304
320
32.2
1060
314
330
33.3
1095
323
340
34.4
1125
333
350
35.5
102
Quantity Type
Mass
Linear Measure
Temperat ure Pressure
Imperial Units Pounds (lb) Short Ton (2000 lbs) Long Ton (2240 lbs) Inches
Metric Units
Multiply Value by the following factors to convert from: Imperial to Metric to Metric Imperial
Kilogram (kg)
0.454
2.20
Metric Ton
0.907
1.10
Metric Ton
1.02
0.984
Millimetres
25.4
0.0391
Feet
Millimetres
305
0.00328
Feet
Meters
0.305
3.28
Yard
Meter
0.914
1.09
Miles Fahrenhe it Pounds/ Square Inch
Kilometre
1.61
0.621
Celsius
o
5.9 x ( F-32)
9.5 x(oC+32)
Kilopascal
6.89
0.145
Megapascal
0.00689
145
103
Metric / imperial conversion factor (2)
Quantity Type
Imperial Units
Square feet Area
Square inch Acres Cubic inches
Volume
Cubic Feet
Density
Gallons (US) Pounds/cubi c inch Foot pound
Energy Mass/Uni t length
Pounds/foot Tons/Mile
Metric Units Square meter Square millimetre Hectares Cubic centimetres Cubic meters Litre Kilogram/cu bic metre Joule Kilo/meter Metric Ton/Meter
General Information
Multiply Value by the following factors to convert from Imperial Metric to to Metric Imperial
CE = C + (Mn + Si) + (Cr + Mo + V) + (Ni + Cu) = (percent) 6 5 15 Voltsx Amps x Time (Secs) Heat Input =
0.0929
10.8
645
0.00155
0.406
2.47
16.4
0.061
Metal
0.0283
35.3
3.79
0.264
27700
0.0000361
1.36
0.738
1.49
0.672
0.564
1.77
Stainless Steel Tantalum Thorium Tin Titanium Tungsten Uranium Vanadium Yellow Brass Zinc
= Kj/mm Run out length (mm) x 1000
Melting Points of Elements & Alloys (1) Melting Point o C F 1510 2750 2980 5400 1750 3180 232 449.4 1670 3040 3400 6150 1132 2070 1900 3450 905-932 1660-1710 419.5 787 o
104
105
Melting Points of Elements & Alloys (2)
Melting Points of Elements & Alloys (3)
Metal Admiralty Brass Aluminium Aluminium Bronze Antimony Beryllium Beryllium Copper Bismuth Brass Cadmium Cast Iron Grey Chromium Cobalt Copper Cupronickel Gold Hastelloy C Inconel Incoloy Iridium Iron
Melting Point o C F 900-940 1650-1720 660 1220 o
600-655
1190-1215
630 1285 865-955 271.4 930 321 1175-1290 1860 1495 1084 1170-1240 1063 1320-1350 1390-1425 1390-1425 2450 1536
1170 2345 1587-1750 520.5 1710 610 2150-2360 3380 2723 1983 2140-2260 1945 2410-2460 2540-2600 2540-2600 4440 2797
106
Metal Lead Magnesium Manganese Manganese Bronze Mercury Molybdenum Monel Nickel Niobium (Columbium) Osmium Platinum Plutonium Potassium Red Brass Rhodium Selenium Silicon Silver Sodium Carbon Steel
Melting Point o
o
C 327.5 650 1244
F 621 1200 2271
865-890
1590-1630
-38.86 2620 1300-1350 1453
-37.95 4750 2370-2460 2647
2470
4473
3025 1770 640 63.3 990-1025 1965 217 1411 961 97.83 1425-1540
5477 3220 1180 146 1810-1880 3569 423 2572 1760 208 2600-2800
107
Nominal Wall Thickness Chart (1) Nominal Pipe Size (in) 1/8 1/4
OD (mm)
Sch 5
Sch 10
10.29 13.7
0.89 1.24
3/8 1/2
17.1 21.3
3/4 1
Nominal Wall Thickness Chart (2)
XS
Sch 80
Sch 160
XXS
1.73 2.24
2.41 3.02
2.41 3.02
2.31 2.77
2.31 2.77
3.20 3.73
3.20 3.73
4.75
7.46
2.11 2.77
2.87 3.38
2.87 3.38
3.91 4.55
3.91 4.55
5.53 6.35
7.82 9.09
1.65 1.65
2.77 2.77
3.56 3.68
3.56 3.68
4.48 5.08
4.85 5.08
6.35 7.13
9.70 10.16
60.3 73
1.65 2.11
2.77 3.05
3.91 5.16
3.91 5.16
5.54 7.01
5.54 7.01
8.71 9.53
11.07 14.02
3 3 1/2
88.9 101.6
2.11 2.11
3.05 3.05
5.49 5.74
5.49 5.74
7.62 8.08
7.62 8.08
11.10
4 5
114.3 141.3
2.11 2.77
3.05 3.40
6.02 6.55
6.02 6.55
8.56 9.53
8.56 9.53
6 8
168.3 219.1
2.77 2.77
3.40 3.76
7.11 8.18
7.11 8.18
10.97 12.70
10.97 12.70
Sch 20
Std
Sch 40
1.24 1.65
1.73 2.24
1.24 1.65
1.65 2.11
26.7 33.4
1.65 1.65
1 1/4 1 1/2
42.2 48.3
2 2 1/2
6.35
Sch 30
7.04
Sch 60
10.31
Sch 100
Sch 120
Sch 140
11.10 12.70 15.06
14.27 18.23
13.48 15.87 20.62
18.23 23.01
108
109
Nominal Wall Thickness Chart (3)
Nominal Wall Thickness Chart (4)
Nominal Pipe Size (in) 10 12
OD (mm)
Sch 5
Sch 10
Sch 20
Sch 30
Std
Sch 40
Sch 60
XS
Sch 80
Sch 100
Sch 120
Sch 140
Sch 160
273.1 323.9
3.4 4.19
3.40 4.19
6.35 6.36
7.79 8.38
9.27 9.53
9.27 10.31
12.70 14.27
12.70 12.70
15.06 17.45
18.23 21.41
21.41 25.40
25.40 28.57
28.57 33.32
14 16
355.6 406.4
6.35 6.35
7.92 7.92
9.53 9.53
9.53 9.53
11.12 12.70
15.06 16.66
12.70 12.70
19.05 21.41
23.80 26.19
27.76 30.93
31.75 36.52
35.71 40.46
18 20
457.2 508
6.35 6.35
7.92 9.53
11.10 12.70
9.53 9.53
14.27 15.06
19.05 20.62
12.70 12.70
23.80 26.19
29.36 32.51
34.92 38.10
39.67 44.45
45.24 49.99
22 24
558.8 609.6
6.35 6.35
9.53
14.27
9.53 9.53
17.45
24.59
12.70 12.70
30.94
38.89
46.02
52.37
59.51
26 28
660.4 711
7.92
12.7
15.88
9.53 9.53
30 32
762 813
12.7
15.88
9.53 9.53
34 36
863.6 914
9.53 9.53
12.70 12.70
38
965
9.53
12.70
110
12.70 12.70 17.48
12.70 12.70
111
XXS
NOTES
NOTES
112
113
NOTES
NOTES
114
115