HG/T 20537.4-1992 Technical requirements for large diameter austenitic stainless steel welded steel pipes for chemical plants
Some standard content:
Industry Standard of the People's Republic of China
Technical Requirements for Austenitic Stainless Steel Large Diameter Welded Steel Pipes for Chemical Industry HG 20537. 4-92
Editor: Equipment Design Technology Center Station, Ministry of Chemical Industry Approval Department: Ministry of Chemical Industry Implementation Date: May 1, 199.3
Engineering Construction Standard Editing Center, Ministry of Chemical Industry
1993 Beijing
1 Subject Content and Scope of Application
This standard specifies the specifications, dimensions, manufacturing process, technical requirements, test methods, inspection rules, as well as marking, packaging and quality certificates of austenitic stainless steel large diameter welded steel pipes for chemical, petrochemical, pharmaceutical and other industries. This standard applies to austenitic stainless steel large-diameter welded steel pipes for chemical equipment produced by arc welding with filler metal (hereinafter referred to as large-diameter welded pipes) 51
2, and references standards
GB222 "Sampling method for chemical analysis of steel and allowable deviation of chemical composition of finished products"
GB228 "Metal tensile test method"
GB241 "Metal pipe hydraulic test method"
GB232 "Metal bending test method"
GB2102 "General provisions for acceptance, packaging, marking and quality assurance of steel pipes" GB2975 "Sampling provisions for mechanical and process tests of steel" GB3280 "Stainless steel cold-rolled steel plate"
GB4230 "Stainless steel Hot-rolled steel strips of steel
GB4237 Hot-rolled stainless steel plates
GB4239 Cold-rolled stainless steel and heat-resistant steel strips GB4334.5 Test methods for corrosion of stainless steel by sulfuric acid and copper sulfate GB3323 Radiography and quality grading of steel fusion welded butt joints HG20537.1 Selection regulations for welded austenitic stainless steel pipes JB4708 Welding procedure assessment for steel pressure vessels JB/T4709 Welding regulations for steel pressure vessels 52
3 Dimensions, shapes and weights
3.0.1 For large-diameter welded pipes with an outer diameter that conforms to the international general series, see Table A-1 for common specifications; for large-diameter welded pipes with an outer diameter that conforms to the domestic series, see Table A-2 for common specifications. Large-diameter welded pipes with specifications other than those in Table A-1 and Table A-2 may be produced upon agreement between the supply and demand parties, but their technical requirements shall still conform to the relevant provisions of this standard. 3.0.2 The length of large-diameter welded pipes shall be proposed by the purchaser. The length is usually 2m~6m, and the short length shall not be less than 1.5m. Large-diameter welded pipes other than the above lengths can be produced by agreement between the supply and demand parties.
With the consent of the purchaser, large-diameter welded pipes can be made of two or more sections of welded pipes, butted by girth welds, and the girth welds should have the same welding quality requirements as the longitudinal welds. 3.0.3 Appearance
3.0.3.1 A 3m long ruler is used, and the two ends are in contact with the steel pipe, and its local deflection should not be greater than 5mm. Large-diameter welded pipes with a length of less than 3m can be converted according to the actual length and proportion.
3.0.3.2 The ends of large-diameter welded pipes should be free of burrs, and the two ends should be perpendicular to the axis of the steel pipe.
3.0.4 Welded pipes are delivered according to actual weight or theoretical weight. Table A-1 and Table A-2 list the theoretical weights of austenitic stainless steels such as 0Cr18Ni9, 00Cr19Ni10, 0Cr18Ni10Ti, 1Cr18Ni9Ti, etc. If used for 0Cr17Ni12Mo2, 00Cr17Ni14Mo2, the theoretical weight listed in the table should be increased by 0.63%. Theoretical weight calculation formula is shown in Table 3.0.4, Table 3.0.4
Chromium-nickel (titanium) austenitic stainless steel
Chromium-nickel-molybdenum austenitic stainless steel
W0.02491t(Dt)
W= 0. 02507t(Dt)
W——Theoretical weight of welded pipe, kg/mwww.bzxz.net
Density (g/cm)
D——Outer diameter of welded pipe, mm
Wall thickness, mm.
3.0.5 The outer diameter tolerance of large-diameter welded pipes is ±1.0%, and the outer diameter measurement method is converted according to the circumference. On the same section, the difference between the maximum outer diameter and the minimum outer diameter should not be greater than 1.5% of the specified outer diameter.
3.0.6 The wall thickness tolerance of large-diameter welded pipes (excluding welds) shall be in accordance with the provisions of Table 3.0.6.
Nominal diameter
Allowable deviation, %
+Not specified
+Not specified
4 Technical requirements
4.0.1 The chemical composition (melting analysis) of the steel strip or steel plate used for large-diameter welded pipes shall comply with the provisions of GB3280, GB4230, GB4237, and GB4239. Welded pipes are made of hot-rolled or cold-rolled steel strips or steel plates of the steel grades listed in Table 4.0.1. With the agreement of both parties, other grades of austenitic stainless steel plates and strips may also be used for manufacturing. Commonly used steel grades
OCr18Ni9
Cr18Ni10Ti
00Cr19Ni10
Equivalent to AISI code
(1Cr18Ni9Ti)
0Cr17Ni12Mo2
ooCr17Ni14Mo2
Note: 1Cr18Ni9Ti is not recommended for use. Table 4.0.1
Equivalent to AISI code
4.0.2 Large diameter welded pipes shall be manufactured by arc welding with filler metal added. The welding materials and welding processes used shall be evaluated and comply with the provisions of JB4708 and JB/T4709.
4.0.3 Unless otherwise specified, large diameter welded pipes are delivered in the welded state, but the weld area should be pickled and passivated. With the agreement between the supplier and the buyer, solid solution treatment or stabilization treatment can also be carried out after welding. The recommended heat treatment system is shown in Table 4.0.6.1. 4.0.4 Classification
· According to the welding type and flaw detection ratio, large diameter welded pipes are divided into five grades as shown in Table 4.0.4.
o.comWelding type
Double-sided welding or single-sided automatic electric welding with equivalent quality requirements
Single-sided automatic arc welding
Flaw detection ratio
100% radiographic flaw detection
Local radiographic flaw detection
(20%, see 4.0.9.2)
No film
Local radiographic flaw detection
(see 4.0.9.3)
No film
Note: The local flaw detection ratio shall be in accordance with the provisions of 4.0.9.2 and 4.0.9.3. 4.0.5 Surface quality
4.0.5.1 The inner and outer surfaces of large-diameter welded pipes shall be bright, without residual acid and oxide scale, and without defects such as cracks, inclusions, scars, delamination, weld concave, and incomplete penetration on the surface. Surface defects should be removed by grinding, and the grinding area should have a smooth transition with the base material, and the wall thickness after grinding should be no less than the minimum wall thickness specified in 3.0.6. If the depth of the defect exceeds the above minimum wall thickness, welding repair can be carried out after obtaining the consent of the purchaser. The welding materials and welding processes used for welding repair must also comply with the provisions of 4.0.2. After welding repair, the weld area should be filmed and re-inspected according to the requirements of 4.0.9. 4.0.5.2 The inner and outer welds of large-diameter welded pipes should be flush with the surface of the welded pipe or have a uniform convexity.
The weld seam should meet the following requirements:
The outer side should not be greater than 50% of the wall thickness, but the maximum is 3mm; whichever is smaller. The inner side should not be greater than 25% of the wall thickness, but the maximum is 3mm, whichever is smaller. The inner and outer weld surfaces should be relatively smooth, without unevenness, and the weld and the base material should have a smooth transition, and the internal welding phenomenon is not allowed.
With the agreement between the supplier and the buyer, large-diameter welded pipes with the excess height on both sides or one side of the weld removed can be provided.
4.0.6 Mechanical properties
so.com4.0.6.1 The mechanical properties of the steel plates or strips used for large-diameter welded pipes shall comply with the provisions of Table 4.0.6.1. The steel quality certificate data of the steel plates or strips may be used as proof.
Heat treatment system and mechanical properties
Steel plates, steel strips or welded pipes
OCr18Ni9
OCr18Ni10Ti
(ICr18Ni9Ti)）
00Cr19Ni10
OCr17Ni12Mo2
00Cr17Ni14M02
Recommended heat treatment system
101 Rapid cooling above 0℃
Rapid cooling above 920℃
Rapid cooling above 1000℃
Rapid cooling above 1010℃
Rapid cooling above 1010℃
Rapid cooling above 1010℃
Table 4.0.6.1
Tensile strength Yield strength.2
Not less than
Not less than
Elongation
Not less than
Note: 1.For 0Cr18Ni10Ti and 1Cr18Ni9Ti, the buyer may require stabilization heat treatment. At this time, the heat treatment temperature is 850~930℃ and rapid cooling.
2.1Cr18Ni9Ti is not a recommended steel grade. 4.0.6.2 Large-diameter welded pipes shall be subjected to tensile tests on welded joints. The tensile test specimens can be cut from the transverse section of large-diameter welded pipes or from the welded test plates at the pipe ends. The test plate material shall be the same furnace number and tube specification as the material used for the welded pipe. The weld on the test plate shall be a continuation of the product weld. The weld shall be located in the center of the specimen and perpendicular to the axis of the specimen. The weld excess height shall be removed mechanically to make it flush with the parent material. The tensile strength of the welded joint shall comply with the provisions of Table 4.0.6.1. 4.0.7 Bending test
4.0.7.1 Large-diameter welded pipes shall be subjected to transverse bending tests on welded joints. The bending specimens are cut from the burst pipe or test plate as required by 4.0.6.2. Unless otherwise specified in 4.0.7.2, two bending specimens are taken, one for face bending and the other for back bending (i.e., the outer surface and inner surface of the pipe are respectively at the maximum bending surface).
4.0.7.2 For large-diameter welded pipes with a wall thickness greater than 10mm, two side bending 57
specimens can be used instead of the face bending and back bending in 4.0.7.1. The side bending specimen has a thickness of 10mm and a width equal to the wall thickness.
4.0.7.3 Regardless of the type of bending specimen, the weld is located in the center of the specimen, perpendicular to the axis of the specimen, and the weld is in the maximum bending position during the bending test. During the bending test, the diameter of the bending core is equal to three times the thickness of the specimen. The specimens of large-diameter welded pipes of grades I, II, and III are bent to 180°, and the specimens of large-diameter welded pipes of grades V and V are bent to 90°. There shall be no cracks or other defects exceeding 3.2mm in length in the weld area. If the length of the crack at the corner of the sample edge is not more than 6.4mm, it can be ignored. 4.0.8 Water pressure test
4.0.8.1 Except for the provisions of 4.0.8.2 and 4.0.8.3, large-diameter welded pipes shall be subjected to water pressure test one by one. Usually, the water pressure test pressure shall be in accordance with the provisions of Table 4.0.8.1. With the agreement of both parties, the purchaser may also propose a test pressure different from that in Table 4.0.8.1. Table 4.0.8.1
Wall thickness series
Water pressure test pressure, MPa
4.0.8.2 With the agreement of both parties, the pressure test of the system or equipment can be used to replace the water pressure test of large-diameter welded pipes.
4.0.8.3 With the agreement of both parties, the weld flaw detection method can be used to replace the water pressure test of welded pipes. The specific method and qualified indicators shall be agreed by both parties. 4.0.8.4 During the water pressure test, the test time should be long enough to check that the welds are free of leakage. After the water pressure test, the water in the pipe should be removed and dried. 4.0.9 Nondestructive inspection of welds
4.0.9.1 Large-diameter welded pipes should be subjected to weld radiographic inspection according to GB3323 based on the classification requirements of 4.0.4. 100% radiographic inspection is qualified at level I: partial radiographic inspection is qualified at level severe.
4.0.9.2 When conducting partial radiographic inspection, the inspection length should not be less than 20% of the length of each weld.
4.0.9.3 For large-diameter welded pipes using single-sided automatic arc welding, the weld local inspection length is 150mm per welder, and 15m of the weld should be inspected for radiographic inspection every 15m.
Other non-destructive testing methods may be used to inspect welds upon agreement between the supplier and the buyer.
Test method
The test method for large-diameter welded pipes shall be in accordance with the provisions of Table 5. Item
Metal analysis
Tensile test
Tensile test of welded joint
Bending test of welded joint
Hydraulic pressure test
Radiographic inspection
Outer diameter, wall thickness
Surface quality
Quantity and location of sampling
One for each furnace number (quality assurance certificate of raw materials can be used) (quality assurance certificate of raw materials can be used)
One for every 60m in each batch
Two samples for every 60m in each batch
According to the classification requirements of 4.0.4
Test method
GB228 and this standard
GB232 and this standard
GB3323
Note: Welded pipes produced with the same outer diameter and wall thickness and the same welding process are considered as one batch. 60
Inspection rules
6.0.1 Welded pipes shall be inspected in batches, and each batch shall consist of steel pipes of the same furnace number, the same specification and the same welding process.
6.0.2 The number of samples to be taken for each inspection shall be in accordance with the provisions of Table 5. 6.0.3 The re-inspection and judgment of large-diameter welded pipes shall be in accordance with the provisions of GB2102. 614 Grading requirements
Test methods
GB228 and this standard
GB232 and this standard
GB3323
Note: Welded pipes produced with the same outer diameter and wall thickness and the same welding process are considered a batch. 60
Inspection rules
6.0.1 Welded pipes shall be inspected in batches, and each batch shall consist of steel pipes with the same furnace number, the same specification and the same welding process.
6.0.2 The number of samples to be taken for each inspection shall be in accordance with the provisions of Table 5. 6.0.3 The re-inspection and judgment of large-diameter welded pipes shall be in accordance with the provisions of GB2102. 614 Grading requirements
Test methods
GB228 and this standard
GB232 and this standard
GB3323
Note: Welded pipes produced with the same outer diameter and wall thickness and the same welding process are considered a batch. 60
Inspection rules
6.0.1 Welded pipes shall be inspected in batches, and each batch shall consist of steel pipes with the same furnace number, the same specification and the same welding process.
6.0.2 The number of samples to be taken for each inspection shall be in accordance with the provisions of Table 5. 6.0.3 The re-inspection and judgment of large-diameter welded pipes shall be in accordance with the provisions of GB2102. 61
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