Some standard content:
National Standard of the People's Republic of China
Steel castings for pressure purposes1996
GB/T 16253
eqv ISO 4991-1994
This standard is equivalent to the international standard ISO4991-1994 "Pressure Steel Castings". The comparison of the steel casting grades in this standard and those in ISO4991 is shown in Appendix A (reference).
1 Subject content and scope of application
This standard specifies the technical requirements, test methods, inspection rules, marking and supplementary requirements for pressure steel castings. This standard applies to pressure steel castings, including pressure steel castings for pressure vessels produced in accordance with the requirements of the "Regulations on Safety Technical Supervision of Pressure Vessels" and pressure steel castings not produced in accordance with the requirements of the "Regulations on Safety Technical Supervision of Pressure Vessels". This standard does not include the welding process of pressure steel castings for cast-welded structures and the performance of weldments. 2 Reference standards
GB222 Sampling method for chemical analysis of steel and allowable deviation of chemical composition of finished products GB223 Chemical analysis methods for steel and alloys
Metal tensile test method
GB 228
GB/T229
Metal Charpy (U-notch) impact test method GB4334.1~4334.5 Stainless steel corrosion test method GB4338
GB5613
GB5677
Metal high temperature tensile test method
Method for indicating cast steel grades
Method for radiography and film grade classification of cast steel parts GB6060.1
Surface roughness comparison sample casting surface
GB 6397
GB 6414
GB6967
GB7233
GB9443
GB9444
GB11351
Metal tensile test specimens
Dimensional tolerances of castings
Medium and high strength stainless steel castings for engineering structuresUltrasonic flaw detection and quality rating methods for steel castingsPenetrant flaw detection and defect indication rating methods for steel castingsMagnetic particle flaw detection and quality rating methods for steel castingsTolerance of casting weight
GB/T 12778
GB/T 15056
Method for measuring Charpy impact fracture of metal
Method for evaluating casting surface roughness
Regulations for Safety Technical Supervision of Pressure Vessels
3 Technical requirements
3.1 General requirements
3.1.1 Pressure-bearing steel castings for pressure vessels shall comply with the relevant provisions of the "Regulations for Safety Technical Supervision of Pressure Vessels". When required by the contract, the first production of castings (including processes, technical documents, etc.) shall be approved by the labor department's boiler and pressure vessel safety supervision agency and relevant departments. Approved by the State Bureau of Technical Supervision on March 28, 1996 and implemented on November 1, 1996
GB/T16253-1996
3.1.2 The purchaser may select the supplementary requirements for pressure-bearing steel castings in Chapter 7 as needed and specify them in the contract. The technical requirements and inspection rules of the selected items, if not specified in this standard, shall be negotiated by the supply and demand parties and shall be indicated in the contract. 3.2 Grade and chemical composition
The grade of cast steel shall be expressed in accordance with the provisions of GB5613, see Table 1. The melting chemical composition of each grade of cast steel shall comply with the provisions of Table 1, chemical composition
ZG240-450A
ZG240-450AG
ZG240-450B
ZG24Q-450BG
ZG240-450BD
ZG280-52031,4)
No. 1)|| tt || tt||ZG20 Cr2M01D
ZG17Cr1MoIVG
1.200.035
Ferrite and martensitic alloy steel
2, 50
ZG16Cr5MoG
ZG14Cr9Mo1G
ZG14Cr12Ni1MoG
ZG08Cr12Ni1MoG
ZG08Cr12Ni4Mo1G
ZG08Cr12Ni4Mo1D
ZG23Cr12Mo1NiVG
ZG14Ni4D
ZG24Ni2MoD
ZG22Ni3Cr2MoAD
ZG22Ni3Ct2MoBD
ZG03Cr18Ni10
ZG07Cr20Ni10
ZG07Cr20Ni10G
ZG07Cr18Ni10D
GB/T 16253—1996
Table 1 continued
0.035!0.035
0.0300.030
0.0300.030
Austenitic stainless steel
ZG08Cr20Ni10Nh
ZG03Cr19Ni11Mo2
ZG07Cr19Ni11M02
ZG07Cr19Ni11Mo2G
ZG08Cr19Ni11Mo2Nb||tt ||ZG03Cr19Ni11M03
ZG07Cr19Ni11M03
GB/T16253-1996
Continued Table 1
Note: 1) The symbols "A\" and "B\" at the end of the grade indicate different grades, "G\" indicates that it is used for high temperature, and "D\" indicates that it is used for low temperature. 2) Except for those in the specified range, they are all maximum values, Mo
3) When carbon is lower than the maximum value, for every 0.01% reduction in carbon, manganese is allowed to be 0.04% higher than the upper limit until the maximum manganese content reaches 1.40%. 4) For certain products, with the agreement of both the supplier and the buyer, they can be supplied as C≤0.30% and Mn≤0.90%. 5) For thin-section castings, the minimum chromium content is allowed to be 1.00%. 6) Depending on the wall thickness, the nickel content can be less than 1.00%. %
3.2.2 Elements not listed in Table 1 shall not be intentionally added without the consent of the purchaser. Unless otherwise specified by the purchaser, the manufacturer shall ensure that the residual elements in carbon steel do not exceed the following content (%): Cr is 0.40, Mo is 0.15, Ni is 0.40, V is 0.03, Cu is 0.40, and the total content of each residual element (Cr+Mo+Ni+V+Cu) does not exceed 1.00%. In this case, the manufacturer may not make a chemical analysis of the residual elements. 3.3 Manufacturing
3.3.1 Refining method
Cast steel shall be smelted in an open hearth, electric furnace or oxygen converter, and may be further degassed or refined outside the furnace. 3.3.2 Heat treatment
3.3.2.1 The heat treatment type of castings and test blocks shall comply with the provisions of Table 2. When a certain grade has more than one type of heat treatment, the manufacturer may choose any type of heat treatment unless otherwise specified in 7.5. 3.3.2.2 Heat treatment temperatures are shown in Table 2. Except for 7.6 Unless otherwise specified, as long as all the specified performance requirements are met, the manufacturer is allowed to make appropriate adjustments to the heat treatment temperature in Table 2. 280-520G
ZG280-520D
ZG19MoG
10ZG29Cr1MoD
ZG15Cr1MoG
ZG14MoVG
ZG12C12Mo1GbzxZ.net
GB/T16253-1996
Heat treatment and mechanical properties
Mechanical properties!
Ferritic and martensitic alloy steel
118135
(Q--T)
Heat treatment 3
Austenite
Temperature
ZG16Cr2M01G
ZG20Cr2Mo1D
ZG17C11Mo1VG
ZG16Cr5MG
ZG14Cr9Mo1G
ZG14Cr12Ni1MoG
ZG08Cr12NiiMoG
ZG08Cr1 2Ni4M01G
ZG08Cr12Ni4Mo1D
23ZG23Cr12M01NiVG
ZG14Ni4D
ZG24Ni2MoD
ZG22Ni3Cr2MoAD
ZG22Ni3Cr2MoBD
GB/T16253—1996
Table 2
Mechanical properties
(Nac+T)
Room temperature 6)
--7027
Nac +T
Heat treatment 2.3)
Austenite
Curing temperature cooling
11000~
105052
ZG03Cr18Ni10
ZG07Cr20Ni10
ZG07Cr20Ni10G
ZG07Cr18Ni10D
ZG08Cr20Ni10Nb
33ZG03Cr19Ni11Mo2
1ZG07Cr19Ni11Mo2
ZG07Cr19Ni11M02G
ZG08Cr19Ni11M02Nb
1ZG03Cr19NiJ1Mo3
38ZG07Cr19Ni11Mo3
GB/T16253-1996
Table 2 continued
Mechanical properties\）
Note: 1) Except for those in the specified range, all are minimum values. 2) The meaning of heat treatment type symbols
A: Annealing (heating to above Acs, furnace cooling) N: Normalizing (heating to above Acs, air cooling) 470~
Q: Tempering (heating to above Acs, liquid quenching) T: Tempering
Nac: (heating to above Ac, rapid air cooling) S: Solution treatment
The heat treatment methods in brackets are only applicable to specific situations.
195945
3) The meaning of the cooling method symbols:
a: air cooling f: furnace cooling 1 liquid quenching or liquid cooling ac: rapid air cooling type
heat treatment 2). 3)
Austenitizing
Temperature
210501
≥1050
[l 0501
21 050/ j1
≥10501
GB/T16253-1996
4) If the minimum yield strength requirements are met, the lower limit of the tensile strength is allowed to be reduced to 500MPa. 5) After cooling to below 100C, subcritical heat treatment can be adopted: 820~870℃, followed by air cooling: 6) This cast steel is generally used in situations where the temperature exceeds 525℃. 7) If the purchaser does not restrict, liquid cooling can also be used. 8) Rapid air cooling can also be used depending on the thickness of the casting. 9) The impact value at this temperature has been verified by test. 3.3.3
3.3.3.1 Except for welding repairs not allowed by the contract, general defects of castings can be welded without the prior consent of the purchaser. 3.3.3.2 For major welding repairs, see 7.7 and 7.8. 3.3.3.3 The welding procedure approval test shall be negotiated by both parties, and welding repairs shall be carried out according to the approved procedures. 3.3.3.4 The pits and welded areas on the castings after the defects are removed shall be inspected by the same non-destructive inspection criteria as the castings. 3.3.4 Test blocks
3.3.4.1 The test blocks representing the mechanical properties of a batch of castings include single casting test blocks and attached casting test blocks. Except as specified in 7.9, the manufacturer can choose one of them.
The single cast test block shall be cast with the same furnace steel and heat treated in the same furnace as the casting it represents. 3.3.4.3 The casting location, casting method and cutting method of the cast test block shall be negotiated by the supplier and the buyer. The cast test block must be cut from the casting only after all heat treatments are completed.
3.3.4.4 The test blocks are divided into the following three types. Unless otherwise specified in 7.10, the manufacturer may choose type 1 test block. Type 1 test block: thickness is 28mm, and the test block drawing shall comply with the provisions of Figure (b) or (c) in GB6967. Type 1 test block: TXT test block, the test block drawing shall be negotiated by the supplier and the buyer. Type II test block: TX3TX3T test block, the test block drawing shall be negotiated by the supplier and the buyer. T is the maximum thickness of the main section of the casting (mm), which shall be specified by the buyer in the contract. 3.4 Mechanical properties
3.4.1 The room temperature mechanical properties and low temperature impact properties of 28 mm thick Type 1 test blocks shall comply with the provisions of Table 2. 3.4.1.1 The values in Table 2 are as follows. For non-austenitic steel, the upper yield point is 0su, or the total elongation stress is α10.5, or the non-proportional elongation stress is opn.2. For austenitic steel, it is pl.n; if αpo.2 is measured, the difference below the specified value in the table shall not exceed 30 MPa. 3.4.1.2 Except as otherwise specified in 7.11, the section reduction rate and room temperature impact properties in Table 2 may be tested by the manufacturer at their option. 3.4.1.3 Regardless of room temperature or low temperature impact, the impact properties in Table 2 are the average value of the impact absorption energy of three Charpy (V-notch) impact test specimens. One of the three single values is allowed to be lower than the specified average value, but shall not be lower than 70% of the specified average value. 3.4.2 If the casting is used at high temperatures, the non-proportional elongation stress specified in Table 3 shall be used in the design. 3.4.3 For the durability of cast steel, see Appendix B (reference). 3.5 Surface quality and internal quality
3.5.1 All castings shall be visually inspected to ensure that there are no defects such as pouring or riser residues, sand adhesion, oxide scale, cracks, etc. 3.5.2 The purchaser may add additional requirements for the surface quality and internal quality of castings (see 7.15 and 7.16). 3.6 Shape, size and tolerance
The shape and size of castings shall comply with the requirements of the drawings or contracts, and the dimensional tolerance shall comply with the provisions of GB6414. 152
ZG240-450AG
ZG240-450BG
ZG280-520G
ZG19MoG
ZG15CrIMoG
ZG12Cr2M01G
ZG16Cr2Mo1G
ZG17Cr1Mo1 VG | | tt | | ZG14Cr9M01G | 16253--1996
Minimum value of po.2 or u1:5 at high temperature\Table 3
Po.2 or pl. at the following temperatures (C). \, reference heat treatment?
N(+T),Q+T
N(+T),Q+T
N(-T),Q+T
N+T,QT
N+T,Q+T
N+T,(Q+T)
N+T.Q+T(Nac+T)
Nac+T.Q+T
Note: 1) The values in the table can be revised if more data are available. 20504)
100150200|250300|350|400|450|500|550240|235215195175160145140|135130240235|215|195175160145
280265250|23 0|215200|190
140135130
180170155
250|240|[230|215|205|185|170|160]155
150,140
290 285275260250240230220 | 205195180160 | | tt | 10400395385375365350335/320300/260420|410395385|375365355335320295|265360|333|305|285|275|270265|260|255550 535|515 500|485/470|455|140540510|480|460450440|430|410390370|34029023019511
145135
120|116|113|10
125/120/116|113/10
2) Temperature and cooling conditions are shown in Table 1.
3) For ZG240-450AG~ZG23Cr12Mo1NiVG, it is opn.2; for ZG07Cr20Ni10G and ZG07Cr19Ni11Mo2C, it is pl.e. The po.2 of austenitic steel is 30MPa lower than p1.
4) The stress value at 50℃ is obtained by interpolation and is only for design purposes and not for verification. 4 Test method
Preparation inspection and test shall be carried out in accordance with the provisions of Table 4. Table 4 Test standards
Inspection items
Chemical analysis
Tensile properties
Tensile properties at high temperature
Impact properties
Surface quality and intrinsic
Quality Welding repair
Dimension tolerance, weight tolerance
Intergranular corrosion resistance
Test standards
GB4338
GB/T 229 GB/T 12778
GB 6060. 1 GB/T 15056
GB9443
GB9444
GB7233
GB5677
GB 6414 GB 11351
GB 4334. 1~4334. 5
Technical requirements of this standard
3. 2,7. 1 ~~ 7. 3
3. 4. 1,7.12,7. 13
3. 5. 1,3. 3. 3. 4,7.15,7. 163. 6,7.17
5 Inspection rules
5.1 Batch
Castings shall be submitted for inspection and acceptance in batches.
5.1.1 Chemical composition inspection, each furnace and tank is a batch. GB/T16253--1996
5.1.2 Mechanical property inspection, except as otherwise provided in 7.20, castings of the same type with the same furnace and tank number, the same furnace heat treatment and a unit weight of no more than 1000kg are a batch, and the total weight of each batch of castings shall not exceed 5000kg. Each casting with a unit weight greater than 1000kg is a batch. 5.2 Sampling
5.2.1 Chemical analysis sampling
For smelting analysis, take one sample from each batch. The sampling method shall comply with the provisions of GB222. 5.2.2 Mechanical properties sampling
5.2.2.1 For room temperature tensile test, take a tensile specimen from the test block representing each batch of castings. The specimen shall be R16 type in GB6397. 5.2.2.2 For high temperature tensile test, the specimen shall comply with the provisions of GB4338. 5.2.2.3 For impact test, take three Charpy (V-notch) standard specimens from the test block representing each batch of castings. The specimen shall comply with the provisions of GB/T229.
5.2.2.4 The sampling positions of tensile and impact specimens are as follows: Type I test blocks comply with the provisions of GB6967, Type 1 test blocks are at the test block axis, and Type II test blocks comply with the provisions of Figure 1.
5.3 Judgment rules
If the test results meet the technical requirements of 3.2.1, 3.4.1, 3.5.1 and 3.6 (or the mechanical properties re-test results meet the technical requirements of 5.4.1 and 5.4.2) and the supplementary requirements specified in the contract, the batch of castings is qualified and accepted; otherwise, it is unqualified and the purchaser may reject the batch of castings.
If the mechanical properties do not meet the requirements, the manufacturer may re-test according to the provisions of 5.4 or re-heat treat according to the provisions of 5.5. 5.3.1
5.3.2 If the mechanical properties test results do not meet the requirements due to the following reasons, the test is invalid. At this time, another sample can be taken from the same batch of test blocks for testing.
The sample is poorly processed or defective;
The testing machine malfunctions or the test operation is improper; The tensile test specimen breaks outside the gauge length.
Figure 1 Sampling position of π-type test block
GB/T 16253-1996
5.4 Retest
When the mechanical properties test results do not meet the technical requirements, except for the case of 5.3.2, the manufacturer may take another sample from the same batch of test blocks and repeat the test according to the following provisions. If the retest results still do not meet the following requirements, the manufacturer may re-heat treat according to the provisions of 5.5. 5.4.1 Retest of tensile test: Take two more samples for test, and the retest results of each sample shall meet the technical requirements. 5.4.2 Retest of impact test: Take three more samples for test, and recalculate the average value of the original test plus the retest, a total of six samples. The new average value and the retested individual values shall meet the technical requirements. 5.5 Reheat treatment
A batch of castings and test blocks that failed the mechanical properties test or retest may be reheat treated. The reheat treated castings and test blocks shall be treated as a new batch for all mechanical properties tests. Without the consent of the purchaser, reheat treatment shall not be performed more than twice (tempering is not limited). 6 Marking, quality certificate, packaging, transportation and storage 6.1 Marking
6.1.1 In addition to 6.1.2, each casting shall be cast or printed with the following marks on the appropriate non-machined surface: manufacturer name or code;
b. Melting furnace number, inspection batch number or their identification number. 6.1.2 Small castings can be marked in batches, and a label with a mark shall be hung in each batch. 6.1.3 Packaging marks shall be in accordance with the contract provisions.
6.2 Quality certificate and other documents
Each batch of castings delivered shall be accompanied by a quality certificate, including: a.
Manufacturer name;
Order contract number;
Casting name, drawing number;
Casting steel grade, melting furnace number, batch number;
Heat treatment type;
All test results (including supplementary requirements) or retest results; This standard number;
Others.
The quality certificate shall be signed by a representative of the manufacturer's inspection department. Other documents include the supervision inspection certificate issued by the labor department's boiler and pressure vessel supervision agency. 6.3 Packaging, transportation and storage
6.3.1 Packaging materials, packaging technology and methods shall comply with the contract provisions. 6.3.2 Transportation methods, transportation conditions and precautions shall comply with the contract provisions. 6.3.3 Castings shall be protected from rust during storage. 7 Supplementary requirements
7.1 Check analysis
It shall be carried out by the purchaser and samples shall be taken on test blocks or specimens representing castings. The samples shall be drilled at least 6 mm below the casting surface. The allowable deviation of the check analysis for the specified smelting analysis can refer to the provisions of Table C1 in Appendix C (reference). The allowable deviation when the elements exceed the range of Table C1 shall be negotiated by the supply and demand parties.
7.2 Finished product analysis
It shall be carried out by the purchaser and samples shall be taken on finished castings. The samples shall be drilled at least 6 mm below the casting surface. 7.3 Chemical analysis of residual elements
7.4 Steelmaking method report
The manufacturer shall report the steelmaking method to the purchaser. 7.5 Selection of heat treatment type
Select a type in Table 2.
7.6 Heat treatment process details
7.7 Major welding repair
GB/T 16253—1996
After removing the defect, the depth of the pit exceeds 25mm or 20% of the wall thickness of the casting (the smaller of the two); or the area exceeds 65cm2; or the casting leaks during the water pressure test, which are all considered major welding repairs. Major welding repairs must be agreed by the purchaser in advance. 7.8 Welding repair drawings
Show the welding repair location and scope in drawings or photos, and provide these information to the purchaser. 7.9 Selection of single casting test blocks or attached casting test blocks. 7.10 Selection of type I or type II test blocks
When the maximum thickness of the main section of the casting T>28mm, type I test blocks can be selected, and when T>50mm, type III test blocks can be selected. When type I or sub-type test blocks are selected, the mechanical property requirements in Table 2 are only applicable to castings with the maximum thickness specified in Table 5. 7.11 Selection of section shrinkage or room temperature impact properties. 7.12 Lateral expansion of impact test specimens.
7.13 Fiber section ratio of impact test specimens
7.14 Verification test of specified non-proportional elongation stress at high temperature. 7.15 Surface roughness.
7.16 Non-destructive testing
Including penetrant testing, magnetic particle testing, radiography and ultrasonic testing. 7.17 Weight and weight tolerance
The weight tolerance of castings shall comply with the provisions of GB/T11351. 7.18 Intergranular corrosion test.
7.19 Pressure sealing
The test can be carried out on machined or unmachined castings. Before the test, the castings shall not be oxidized and shall not have any protective coating or plating.
For castings for pressure vessels, the test conditions (including the test medium, pressure, temperature, time, etc.) specified in the vessel test standards can be referred to for testing; for castings not produced in accordance with the requirements of the "Regulations on Safety Technical Supervision of Pressure Vessels", the test conditions shall be negotiated by the supply and demand parties. 7.20 Batch grouping for mechanical properties test
The batch grouping requirements shall be in accordance with those proposed by the purchaser.
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