GB/T 38807-2020 English PDF (GB/T38807-2020)

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GB/T 38807-2020: General specification for super austenitic stainless steels
GB/T 38807-2020
General specification for super austenitic stainless steels
ICS 77.140.20
H40
National Standards of People's Republic of China
General technical requirements for super austenitic stainless steel
2020-06-02 released
2020-12-01 implementation
State Administration for Market Regulation
Issued by the National Standardization Management Committee
Preface
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by the China Iron and Steel Association.
This standard is under the jurisdiction of the National Steel Standardization Technical Committee (SAC/TC183).
Drafting organizations of this standard. Central Iron and Steel Research Institute, Metallurgical Industry Information Standards Institute, Pangang Group Jiangyou Great Wall Special Steel Co., Ltd., Fu
Shun Special Steel Co., Ltd., Jiangsu Wujin Stainless Co., Ltd., Yongxing Special Material Technology Co., Ltd., Jiangsu Shenyuan Group
Limited company.
The main drafters of this standard. Chen Haitao, Luan Yan, Fang Yi, Dai Qiang, Feng Hanqiu, Lu Lun, Song Jianxin, Wang Jianyong, Zhang Guofu, Cui Hong, Xu Ding,
Tu Yuguo.
General technical requirements for super austenitic stainless steel
1 Scope
This standard specifies the terms and definitions, classification, order content, size, shape, weight, technical requirements, and tests of super austenitic stainless steel
Methods, inspection rules, packaging, marking and quality certificates.
This standard applies to hot-rolled or forged super austenitic stainless steel bars with a nominal diameter or side length not greater than 550 mm (hereinafter referred to as steel
Baton).
2 Normative references
The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article
Pieces. For undated references, the latest version (including all amendments) applies to this document.
GB/T 222 Allowable deviation of chemical composition of finished steel
GB/T 223.4 Determination of manganese content in iron, steel and alloy by potentiometric titration or visual titration
GB/T 223.5 Iron and steel-Determination of acid-soluble silicon and total silicon content-Reduced molybdosilicate spectrophotometric method
GB/T 223.11 Determination of chromium content in steel and alloy by visual titration or potentiometric titration
GB/T 223.18 Methods for chemical analysis of iron, steel and alloy-The sodium thiosulfate separation-iodometric method for the determination of copper content
GB/T 223.25 Methods for chemical analysis of iron, steel and alloy-The dimethylglyoxime gravimetric method for the determination of nickel content
GB/T 223.28 Methods for chemical analysis of iron, steel and alloy The α-benzoin oxime gravimetric method for the determination of molybdenum content
GB/T 223.36 Methods for chemical analysis of iron, steel and alloy. Distillation separation-neutralization titration method for the determination of nitrogen content
GB/T 223.40 Steel and alloy determination of niobium content-Chlorosulfonol S spectrophotometric method
GB/T 223.43 Determination of tungsten content in iron, steel and alloy by gravimetric method and spectrophotometric method
GB/T 223.53 Methods for chemical analysis of iron, steel and alloy-The flame atomic absorption spectrophotometric method for the determination of copper content
GB/T 223.62 Methods for chemical analysis of iron, steel and alloy-The butyl acetate extraction photometric method for the determination of phosphorus content
GB/T 223.64 Determination of manganese content in steel and alloy by flame atomic absorption spectrometry
GB/T 223.67 Steel and alloy determination of sulfur content-Methylene blue spectrophotometric method
GB/T 223.72 Gravimetric method for determination of sulfur content in steel and alloy
GB/T 226 Steel Macrostructure and Defect Inspection Method
GB/T 228.1 Tensile Test of Metallic Materials Part 1.Room Temperature Test Method
GB/T 229 Charpy pendulum impact test method for metallic materials
GB/T 230.1 Rockwell Hardness Test of Metallic Materials Part 1.Test Method
GB/T 231.1 Brinell Hardness Test of Metallic Materials Part 1.Test Method
GB/T 702-2017 Hot-rolled steel bar size, shape, weight and allowable deviation
GB/T 908-2019 Forged steel bar size, shape, weight and allowable deviation
GB/T 1979 Structural steel macrostructure defect rating chart
GB/T 2101 General requirements for acceptance, packaging, marking and quality certificate of section steel
GB/T 2975 Steel and steel product mechanical performance test sampling location and sample preparation
GB/T 4162 Ultrasonic testing method for forged and rolled steel bars
GB/T 4334-2020 Corrosion of metals and alloys, austenite and ferrite-austenite (duplex) stainless steel intergranular corrosion test
method
GB/T 6394 Method for determination of average grain size of metals
GB/T 6402 Ultrasonic Testing Method for Steel Forgings
GB/T 7736 Low-magnification defect ultrasonic inspection method of steel
GB/T 8170 Numerical rounding rules and the expression and determination of limit values
GB/T 10127 Stainless steel ferric chloride crevice corrosion test method
GB/T 10561-2005 Determination of the content of non-metallic inclusions in steel Standard Grading Chart Microscopic Inspection Method
GB/T 11170 Determination of multi-element content of stainless steel by spark discharge atomic emission spectrometry (conventional method)
GB/T 13305 Metallographic determination of α-phase area content in stainless steel
GB/T 15970.2 Corrosion stress corrosion test of metals and alloys Part 2.Preparation and application of curved beam specimens
GB/T 17505 General technical requirements for delivery of steel and steel products
GB/T 17897 Corrosion of metals and alloys. Test method for pitting corrosion of stainless steel with ferric chloride
GB/T 20066 Sampling and sample preparation methods for the determination of the chemical composition of steel and iron
GB/T 20123 Determination of total carbon and sulfur content of iron and steel-Infrared absorption method after combustion in high frequency induction furnace (conventional method)
GB/T 20124 Determination of nitrogen content of iron and steel inert gas fusion thermal conductivity method (conventional method)
GB/T 37566 Ultrasonic testing method for round steel
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Super Austenitic Stainless Steel
Austenitic stainless steel with high chromium, molybdenum and nitrogen content and a pitting corrosion index PREN not less than 40, which has excellent uniform corrosion resistance,
Pitting corrosion, crevice corrosion and stress corrosion performance.
Note. Pitting resistance index PREN=Cr% 3.3×(Mo% 0.5×W%) 16×N%.
4 categories
4.1 Steel bars are divided into the following two categories according to the processing methods used.
a) Pressure processing steel UP.
1) Hot pressure processing UHP;
2) Cold drawn blank UCD.
b) Steel UC for cutting.
4.2 The use and processing method of steel bars should be specified in the contract, and those not specified shall be supplied as steel for cutting.
5 Order content
The contract or order ordered according to this standard shall at least include the following contents.
a) The standard number;
b) Product name;
c) Brand or unified digital code;
d) Delivery status;
e) size and allowable deviation;
f) weight or quantity;
g) The items or indicators in the standard that should be negotiated between the supplier and the buyer and indicated in the contract. If not indicated, the supplier will choose;
h) Other special requirements.
6 Dimensions, appearance and weight
6.1 The size, shape and allowable deviation of hot-rolled round steel and square steel should meet the requirements of GB/T 702-2017, and the specific requirements should be in the contract
Specify. If it is not specified, it shall be implemented in accordance with Group 2 in Table 1 of GB/T 702-2017.
6.2 The size, shape and allowable deviation of forged round steel and square steel should meet the requirements of GB/T 908-2019, and the specific requirements should be in the contract
Specify. If it is not specified, it shall be implemented in accordance with Group 2 in Table 1 of GB/T 908-2019.
6.3 Upon agreement between the supplier and the buyer and indicated in the contract, steel bars of other sizes, shapes and allowable deviations can be supplied.
6.4 Steel rods are delivered according to actual weight.
7 Technical requirements
7.1 Brand and chemical composition
7.1.1 The uniform digital code, grade and chemical composition (melting analysis) of steel shall meet the requirements of Table 1.
Note. Refer to Appendix A for the comparison of domestic and foreign stainless steel grades.
7.1.2 The allowable deviation of the chemical composition of the steel bar shall meet the requirements of GB/T 222.
7.2 Smelting method
Unless otherwise specified in the contract, steel should be refined outside the furnace. Electroslag remelting smelting can also be used or other standards that can meet the requirements of this standard
He smelt method.
7.3 Delivery status
Steel rods are generally delivered in a hot rolled or hot forged state, and can also be delivered in a solid solution state. It should be specified in the contract when ordering.
7.4 Mechanical properties
7.4.1 The mechanical properties of solution-treated steel bars should meet the requirements of Table 2, and the recommended solution treatment system is shown in Appendix B.
7.4.2 According to the requirements of the buyer, the mechanical properties of the steel bars can be specified separately after negotiation between the supplier and the buyer and indicated in the contract.
a Only when requested by the purchaser and specified in the contract, one of them is selected for inspection.
7.5 Corrosion resistance
According to the requirements of the purchaser, the steel bar shall be negotiated by the purchaser and the purchaser to determine the appropriate test method for corrosion test (intergranular corrosion, pitting corrosion, joint
Crevice corrosion and stress corrosion), and specify in the contract. When not specified, the steel bar shall be subjected to intergranular corrosion according to the E method in GB/T 4334-2020
test.
7.6 Macrostructure
7.6.1 There should be no visible shrinkage holes, bubbles, cracks, inclusions, peeling and white spots on the acid immersion low-power test piece of the cross section of the steel rod. Pair cutting
The steel bars used for processing are allowed to have defects such as subcutaneous inclusions whose depth is not more than half of the nominal dimensional tolerance.
7.6.2 The qualified grade of acid leaching low-magnification defects of steel bars with a nominal size of not more than.200mm shall meet the requirements of Table 3.Nominal size is greater than.200
For mm steel rods, the qualified level of low-magnification defects is determined by the supplier and the buyer through negotiation.
7.6.3 If the supplier can guarantee the low-magnification qualification, ultrasonic testing or other non-destructive testing methods are allowed to replace the low-magnification inspection.
7.7 Non-metallic inclusions
The non-metallic inclusions of the steel rod shall meet the requirements of Table 4.
7.8 Surface quality
7.8.1 There should be no cracks, scars, folds and inclusions on the surface of the steel rod used for pressure processing, and the above defects should be removed. Depth of defect removal should be consistent
In accordance with the provisions of Table 5, the removal width is not less than 5 times the depth, and the maximum removal depth of the same section is not more than one.
Individual small scratches, indentations, pits, and small cracks with a depth of not more than 0.20mm, which do not exceed half of the nominal size tolerance, exist.
According to the negotiation between the supplier and the buyer, the surface of the round steel bar for pressure processing can be delivered by turning or peeling.
7.8.2 The steel bars used for cutting are allowed to have local deficiencies that do not exceed those specified in Table 6 from the nominal size.
7.8.3 After negotiation between the supplier and the buyer and specified in the contract, pickling, turning or grinding can be used to remove the black skin produced by the heat treatment.
7.9 Special requirements
According to the requirements of the buyer, the following inspection items can be added after negotiation between the supplier and the buyer and indicated in the contract.
a) V-notch Charpy impact test;
b) grain size;
c) α phase content;
d) Ultrasonic testing;
e) Other requirements.
8 Test method
8.1 The chemical composition analysis of steel is usually carried out according to GB/T 11170, GB/T 20123, GB/T 20124 or general methods. Press during arbitration
GB/T 223.4, GB/T 223.5, GB/T 223.11, GB/T 223.18, GB/T 223.25, GB/T 223.28, GB/T 223.36,
GB/T 223.40, GB/T 223.43, GB/T 223.53, GB/T 223.62, GB/T 223.64, GB/T 223.67, GB/T 223.72
Provisions.
8.2 Other inspection items and test methods of steel bars should meet the requirements of Table 7.
9 Inspection rules
9.1 Inspection and acceptance
The inspection and acceptance of steel bars are carried out by the supplier's technical quality supervision department.
9.2 Batching rules
Steel bars shall be submitted for inspection and acceptance in batches. Each batch should consist of the same brand, the same furnace number, the same specification, the same processing method, and the same heat treatment
The steel bar composition of the heat. The steel smelted by electroslag remelting is allowed to be used under the condition that the process is stable and the technical requirements of this standard can be guaranteed.
The electrode smelting master furnace number shall be delivered in batches and shall be indicated in the quality certificate.
9.3 Number and location of samples
The sampling number and sampling location of the steel rods should meet the requirements of Table 7.
9.4 Re-inspection and judgment rules
9.4.1 The re-inspection and judgment rules of steel bars shall be in accordance with GB/T 17505...