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This standard is drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 12361-2003 General specification of steel die forgings. In addition to editorial changes, the following main changes have been made with respect to GB/T 12361-2003.
——"Furnace (can) number" has been modified to "furnace number" (see 3.1 hereof; 3.1 of Edition 2003);
——"For the same production card" has been deleted (3.3 of Edition 2003);
——The standard GB/T 5216 (see 5.2.1) that the steel selected for forgings shall meet has been added;
——"The selected steel shall be re-inspected before it can be put into production. Re-inspection items shall be determined according to steel inspection standards.” has been modified to "The steel shall be reinspected according to the inspection items determined by the supplier and the purchaser." (see 5.2.2 herein; 5.2.3 of Edition 2000);
——"Isothermal annealing" has been modified to "isothermal normalizing", and “temperature-controlled cooling" has been modified to "controlled cooling" [see d), e) of 5.3.5.1 herein, d), e) of 5.3.5.1 in Edition 2003];
——"And when the forging cannot be sampled and tested” has been deleted (5.3.7.3 of Edition 2003);
——"When the supplier does meet the conditions" has been deleted (5.4.1 of Edition 2003);
——"The terms such as heat treatment furnace and manufacture batch required to be under the same heat number or strong shot peening required to be added" has been deleted (5.4.2 of Edition 2003);
——"White spot" has been deleted (7.4.1 of Edition 2003);
——"In order to facilitate mold manufacturing, use standard cutting tools" has been deleted (see A.1.3 of Edition 2003);
——"But it shall not be less than 3°" has been deleted (A.1.4.1 of Edition 2003).
This standard was proposed by and is under the jurisdiction of National technical Committee on Metalforming Machinery of Standardization Administration of China (SAT/TC 74).
The previous editions of this standard are as follows:
——GB/T 12361-1990 and GB/T 12361-2003.
Steel die forgings — General specification
1 Scope
This standard specifies the classification, technical requirements, test methods, inspection rules, marking, quality certificate, packaging and transportation for steel die forgings (hereinafter referred to as "forgings").
This standard is applicable to structural steel die forgings produced by forging and pressing equipment such as die forging hammer, hot die forging press, screw press and horizontal forging machine. Forgings of other steel grades may also be used for reference.
This standard serves as the basis for product design department to determine forging technical requirements and sign technical agreements between the supplier and the purchaser, and may also be used as the basis for forging acceptance.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 224 Determination of the depth of decarburization of steels
GB/T 226 Test method for macrostructure and defect of steel by etching
GB/T 228.1 Metallic materials — Tensile testing — Part 1: Method of test at room temperature
GB/T 229 Metallic materials — Charpy pendulum impact test method
GB/T 230 (all parts) Metallic materials — Rockwell hardness test
GB/T 231 (all parts) Metallic materials — Brinell hardness test
GB/T 321 Preferred numbers — Series of preferred numbers
GB/T 699 Quality carbon structure steels
GB/T 700 Carbon structural steels
GB/T 2828 (all parts) Sampling procedures for inspection by attributes
GB/T 2829 Sampling procedures and tables for periodic inspection by attributes (Apply to inspection of process stability)
GB/T 3077 Alloy structure steels
GB/T 5216 Structural steels with specified hardenability bands
GB/T 6394 Determination of estimating the average grain size of metal
GB/T 7232 Terminology of metal heat treatment
GB/T 12362 Tolerances and machining — Allowances of steel die forging
GB/T 12363 Classification of forging functions
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3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
steel-smelting furnace number
furnace number marked on steel products delivered by a steel mill
3.2
Heat treatment furnace number
same forging that is treated once or continuously with the same process specification in the same heat treatment furnace
3.3
manufacture batch
according to the same process specification, all forgings continuously produced in the forging process
4 Classification of forgings
4.1 Forgings are classified according to GB/T 12363.
4.2 Forging classes shall be indicated in product drawings and forging drawings. Those not indicated are Class IV.
4.3 Marking mode:
Forging category — GB/T 12363.
Example: II — GB/T 12363.
5 Technical requirements
5.1 Acceptance basis
Forging drawings, technical agreements and supply contracts signed by the supplier and the purchaser are the main basis for inspection and delivery of finished products of forgings.
5.2 Raw materials
5.2.1 The steel selected for forgings shall meet those specified in GB/T 699, GB/T 700, GB/T 3077, GB/T 5216.
5.2.2 In addition to the requirements of 5.2.1, the steel used for forgings can adopt enterprise standards or special technical agreements signed with steel suppliers as additional requirements for different forging manufacturers.
5.2.3 Carry out steel re-inspection according to the inspection items determined by the supplier and purchaser.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Classification of forgings
5 Technical requirements
6 Test methods
7 Inspection rules
8 Marking, quality certificate, packaging and transportation
Annex A (Normative) Draft angle and fillet radius of forgings
