JB/T 7031-1993 Large mill end cover steel castings JB/T7031-1993 standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T7031-93
Large Mill End Cover Castings
Published on September 21, 1993
Ministry of Machinery Industry of the People's Republic of China
Implementation on July 1, 1994
Mechanical Industry Standard of the People's Republic of China
Large Mill End Cover Castings
1 Subject Content and Scope of Application
JB/T.7031-93
This standard specifies the technical requirements, inspection methods and acceptance rules for simple machine end cover castings (hereinafter referred to as castings). This standard applies to the inspection and acceptance of mill end covers with specifications of 3200 and above. 2 Referenced Standards
GB 6060.1
GB 9444
GB11352
Sampling method for chemical analysis of pins and allowable deviation of chemical composition of finished products Chemical analysis methods for steel and alloys
Metal tensile test method
Metal Charpy (U-notch) impact test method Surface roughness comparison sample casting surface
Magnetic particle inspection and quality rating method for steel castings Carbon steel castings for general engineering
General technical conditions for repair welding of steel castings|| tt||JB/ZQ4000.6
JB/ZQ6109
3 Ordering requirements
Ultrasonic inspection method for steel parts
3.1 The purchaser shall indicate the name, material grade (steel grade), delivery status and supply quantity of the casting in the order contract, and provide the corresponding transfer sample.
3.2 When the purchaser has special requirements, the supply and demand parties shall negotiate and confirm and indicate them in the contract or drawing. 4 Technical requirements
4.1 Chemical composition
The chemical composition of the material grade (steel grade) shall comply with the provisions of Table 1. Table 1 Chemical composition
Grade (Steel Grade)
ZG230-450
ZG270-500
ZG20SiMn
0, 22~0.30
0.32~0.40
0.16~0.23
0.25~0.50
0.25~0.50
0.40~0.60
0.60~0. 90
0.60~0. 90
1.00~1.50
Note: ①For the two grades of ZG230-450 and 2G270-500, the manganese content is allowed to increase by 0.04% for every 0.01% decrease in the upper limit carbon content, but the maximum manganese content shall not exceed 1.20%.
②The total amount of residual elements of Cr, Ni, and Cu shall not exceed 1.00%. If the purchaser has no requirements, the residual elements may not be analyzed. 4.2 Mechanical properties
Mechanical properties shall conform to the provisions of Table 2,
Approved by the Ministry of Machinery Industry on September 21, 1993
Implementation on July 1, 1994
Steel grade (steel grade)
ZG230-450
ZG270-500
ZG20SiMn
4.3 Surface quality
≥230
≥295
JB/T 7031-93
Table 2° Mechanical properties
≥450
4.3.1 The shape and size of the casting shall conform to the requirements of the drawing. The surface shall be free of sand and scale, burrs, excess meat and pouring risers. 4.3.2 The surface is not allowed to have surface defects such as cracks, shrinkage holes, and pinching. The above defects can be removed by grinding and other methods. If necessary, repair welding can be performed.
4.3.3 The roughness of the non-machined surface of the casting should meet the requirements of R, ≤800μm in GB6060.1. 4.4 Repair welding
The supplier can repair the defects of the casting. Repair welding should be carried out in accordance with the provisions of JB/ZQ4000.6. 4.5 Non-destructive testing
When there are non-destructive testing requirements in the contract or drawings, it shall be carried out in accordance with the provisions of Appendix A (Supplement). 5 Test methods and acceptance rules
5.1 Chemical analysis
5.1.1 The supplier shall conduct chemical analysis on each heat of steel, and the sample for chemical analysis shall be prepared in the middle of pouring. The sampling method for chemical analysis samples shall be carried out in accordance with the provisions of GB222.
5.1.2 The chemical analysis method shall be carried out in accordance with the provisions of GB223. 5.2 Mechanical properties test
5.2.1 Test block
5.2.1.1 Test blocks for mechanical properties test shall be taken out during the casting of the waiting part, and can be cast alone or attached. When attached, its position shall be agreed upon by both the supplier and the buyer. The shape, size and cutting position of the test block shall be in accordance with the provisions of GB11352. 5.2.1.2 Single test blocks must be heat treated in the furnace between the casting and the casting. 5.2.2 Tensile test
Tensile test shall be carried out in accordance with the provisions of GB228. 5.2.3 Impact test
Impact test shall be carried out in accordance with the provisions of GB229. The average value of the three specimens shall comply with the provisions of Table 2, and the value of one of the specimens may be lower than the specified value, but shall not be lower than 2/3 of the specified value. 5.3 Re-test
5.3.1 If the mechanical properties test results do not meet the requirements, double the specimens may be taken for re-test. 5.3.2 When the retest results still do not meet the requirements of Table 2, the castings and test blocks can be reheat treated and then retested according to 5.2.2 and 5.2.3.
5.3.3 Without the consent of the buyer, the number of reheat treatments shall not exceed two times. 6 Marking, packaging and certificate of conformity
The supplier must cast a mark on the part to be tested that can indicate the characteristics of the casting. 6.1
6.2 The surface of the casting should be painted with anti-rust paint.
6.3 The casting should be accompanied by a certificate of conformity when it leaves the factory. The certificate of conformity should include the following: a.
Supplier name:
Casting order number, drawing number, part number, name: Cast steel grade:
Smelting furnace number, chemical composition, mechanical properties. JB/T 7031-93
A1 Nondestructive testing
A1.1 Ultrasonic testing
JB/T7031-93
Appendix AbZxz.net
Nondestructive testing of end covers
(Supplement)
Ultrasonic testing is performed after rough machining between the oil retaining rings of the casting (position a shown in Figure A1). In the area 20mm deep from the finished surface of the casting, the quality grade shall comply with Grade 2 specified in JB/ZQ6109, and other areas shall comply with Grade 4. A1.2 Magnetic particle testing
The part above the shaft neck of the casting (position b shown in Figure A1) shall be subjected to magnetic particle testing. The quality requirements shall be evaluated in accordance with GB9444, where linear or point linear defects shall comply with Grade 1, and nonlinear defects shall comply with Grade 2. Figure A1
Schematic diagram of end cover
A2 Nondestructive testing method
A2.1 Ultrasonic testing method shall be carried out in accordance with the provisions of JB/ZQ6109. A2.2 Magnetic particle testing method shall be carried out in accordance with the provisions of GB9444. Additional remarks:
This standard is proposed and managed by the Deyang Large Castings and Forgings Research Institute of the Ministry of Machinery Industry, and this standard is drafted by Shenyang Heavy Machinery. The main drafter of this standard is Li Guiqiao.
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