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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by the China Machinery Industry Federation.
This standard is under the jurisdiction of the National Technical Committee 506 on Heavy Casting and Forging of Standardization Administration of China (SAC/TC 506).
Large exposed gear steel castings — Technical specification
1 Scope
This standard specifies the order requirements, manufacturing process, technical requirements, inspection rules, test methods, acceptance and quality certificate, marking and packaging of large exposed gear steel castings.
This standard is applicable to the ordering, manufacturing and inspection of large gear steel castings adopted sand casting and exposed transmission.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated reference, only the edition cited applies. For undated references, the latest edition of the referenced documents (including any amendments) applies.
GB/T 222 Permissible tolerances for chemical composition of steel products
GB/T 223 (All parts) Methods for chemical analysis of iron, steel and alloy
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 231.1 Metallic materials — Brinell hardness test — Part 1: Test method
GB/T 4336 Carbon and low-alloy steel — Determination of multi-element contents — Spark discharge atomic emission spectrometric method (routine method)
GB/T 5678 Sampling methods of spectrochemical analysis for cast alloys
GB/T 6414 Castings — System of dimensional tolerances and machining allowances
GB/T 7233.1 Steel castings — Ultrasonic examination — Part 1: Steel castings for general purposes
GB/T 9443 Steel and iron castings — Liquid penetrant inspection
GB/T 9444 Steel and iron castings — Magnetic particle inspection
GB/T 15056 Casting surface roughness — Appraising method
GB/T 20066 Steel and iron — Sampling and preparation of samples for the determination of chemical composition
3 Order requirements
3.1 The purchaser shall specify the following items in the in the order contract or order agreement, including the casting name, the implemented standard, material designation, the corresponding technical requirements, the inspection items, the delivery status and the supply quantity, and shall provide the order pattern to the supplier.
3.2 The purchaser shall specify the requirements for surface protection, transportation and storage in the order agreement.
3.3 If there are any processing defects to be finally retained on the casting, the supplier shall explain to the purchaser in advance, and after negotiation between the supplier and the purchaser, the supplier shall provide the location, size and weight of the retained processing defects.
3.4 Additional requirements that proposed by the purchaser other than those specified in this Standard shall be agreed upon by both parties.
4 Manufacturing process
4.1 Smelting
Steel for the castings shall be melted by electric arc furnace, ladle refining furnace or other smelting methods that meet the requirements.
4.2 Casting
Unless otherwise specified, the casting process is decided by the supplier.
4.3 Heat treatment
The castings shall be heat treated, which is determined by the supplier.
4.4 Defect removal and repair welding
4.4.1 Repair welding is allowed for casting defects. Before repair welding, the defects shall be cleaned up and confirmed by magnetic particle inspection or penetrant inspection to meet the repair welding requirements.
4.4.2 Repair welding of casting defects shall be carried out by qualified operators according to process requirements, and welding procedure qualification shall be generally carried out before repair welding.
4.4.3 Defects with a depth of more than 25 mm or over 40% of the section thickness after removal shall be regarded as larger defects, and repair welding of larger defects shall be recorded.
4.4.4 Stress-relief heat treatment shall be carried out after defect repair welding, and the repair welding area shall be tested according to the casting non-destructive testing standard to confirm the repair welding quality.
4.4.5 As agreed by both parties, the treatment method of casting defects after finishing may be carried out according to Annex A.
5 Technical Requirements
5.1 Chemical composition
5.1.1 The chemical composition of each steel casting designation shall comply with the requirements of Table 1.
5.1.2 Unless otherwise specified, the content of residual elements shall not be used as the basis for acceptance.
5.1.3 If required by the purchaser, the chemical composition analysis of finished products may be carried out, and the allowable deviation of the finished product chemical composition shall meet the requirements of GB/T 222.
Foreword i
1 Scope
2 Normative references
3 Order requirements
4 Manufacturing process
5 Technical Requirements
6 Inspection rules and test methods
7 Quality certificate
8 Marking, surface protection, packaging and transportation
Annex A (Informative) Defect treatment method of large exposed gear steel castings after finish machining