JB/T 5940-1991 General technical requirements for high manganese steel castings for engineering machinery
Some standard content:
Machinery Industry Standard of the People's Republic of China
JB/T5940-91
Engineering Machinery
General Technical Conditions for High Manganese Steel Castings
Issued on December 12, 1991
Issued by the Ministry of Machinery and Electronics Industry of the People's Republic of China
Implementation on July 1, 1992
Mechanical Industry Standard of the People's Republic of China
Engineering Machinery
General Technical Conditions for High Manganese Steel Castings
1 Subject Content and Scope of Application
JB/T5940-91
This standard specifies the technical requirements, test methods, inspection rules, as well as marking, packaging, transportation, storage, etc. for high manganese steel castings for engineering machinery. This standard applies to high manganese steel castings (hereinafter referred to as castings) that are subject to impact loads and wear resistance. 2 Reference standards
GB5680
GB223.1~223.7
GB2828
3 Technical requirements
Technical conditions for high manganese steel castings
Chemical analysis methods for steel and alloys
Metal tensile test method
Metal Charpy (U-notch) impact test method Metal Brinell hardness test method
Surface roughness comparison sample casting surface
Batch inspection counting sampling procedure and sampling table (applicable to inspection of continuous batches) The grade and chemical composition of high manganese steel castings shall comply with the provisions of Table 1. Table 1
Casting grades and chemical composition
ZGMn13-3
0.90~1.30
Chemical composition
11.00~14.00
Note: ZGMn13 is a cast high manganese steel, and the Arabic numerals after \_\ represent the variety code. 0.30~0.80
Castings must be treated with water toughening. The mechanical properties of the treated samples shall comply with the provisions of Table 2. 3.2
Table 2 Mechanical properties
ZGMn13-3
Tensile strength
≥686
Elongation 8s
Impact toughness
3.3The metallographic structure of the casting after water toughening shall comply with the provisions of Articles 1.4 and 1.5 of GB5680. 3.4 Casting geometry and size
The casting geometry and size shall comply with the requirements specified in the drawing or order agreement. 3.5 Casting dimensional tolerance
3.5.1 The casting dimensional tolerance value shall comply with the provisions of Table 3, and its tolerance grade shall comply with the provisions of Table 4. Approved by the Ministry of Machinery and Electronics Industry on December 12, 1991 Hard
≤229
Implementation on July 1, 1992
3.5.2 Position of tolerance zone
JB/T5940-91
The tolerance zone shall be symmetrically distributed, that is, half of the tolerance shall be positive and the other half shall be negative (see Figure 1). When the casting has an inclined part, its dimensional tolerance shall be marked symmetrically along the inclined surface (see Figure 2), and the tolerance value shall be selected from Table 3 according to the basic size of the casting.
Basic dimensions of castings
Basic dimensions of castings
Tolerance band of casting dimensions
Minimum limit dimensions
Maximum limit dimensions
Table 3 Tolerance values of casting dimensions
Note: ①Basic dimensions of castings refer to the dimensions given on the drawings, which should include machining allowance and draft angle. Figure 2
②For castings with basic dimensions less than or equal to 16mm, the tolerance value of CT12 is used for grades CT13 to CT15. 3.5.3Different tolerance grades are allowed to be used within a certain local range of the same casting. However, the tolerance values shall be indicated on the drawings or in the relevant technical documents.
JB/T5940—91
3.5.4The tolerance grade of castings shall be indicated on the drawings or specified in the technical documents, otherwise the lowest tolerance grade shall be used. 3.5.5 The wall thickness tolerance is selected one level lower than the tolerance grade selected for the casting. For example, if the selected tolerance grade for the casting is CT13, the wall thickness tolerance is selected as CT14.
3.6 Machining allowance of castings
The machining allowance grade of castings shall comply with the provisions of Table A1 in Appendix A (Supplement); its machining allowance shall comply with the provisions of Table A2.
Batch and mass production
Casting process
Sand mold hand molding
Sand mold machine molding and shell mold
Casting size tolerance grade
Flame mold casting
Small batch and single piece production
Molding materials
Dry and wet sand
Self-hardening sand
12--14
Note: For small batch and single piece production, when the basic size of the casting is not greater than 16mm, its tolerance grade is increased by 2 grades: when it is greater than 16 to 25mm, its tolerance grade is increased by 1 grade.
The holes on the casting should generally be cast. The size and deviation of the casting hole (including semicircular holes, square holes, notches, etc.) should comply with the provisions of Table 5. 3.7
Table 5 Casting hole dimensions and deviations
Basic hole dimensions
Mounting holes
Non-mounting holes
Note: The basic dimensions of casting holes refer to the diameter of holes or semicircular holes, and the side length of square holes or notches. >30~65
The dimensional deviations of the distance between casting holes and the distance from holes to the edge of castings shall comply with the provisions of Table 6. 3.8
Table 6 Dimensional deviations of the distance between holes or between holes and edges Basic dimensions of castings
≤120
3.9 Geometrical shape tolerances of castings
>120~260
>260~500
3.9.1 The flatness and roundness of castings shall comply with the provisions of Table 7 and Table 8 respectively. Table 7
Basic dimensions of castings
Flatness or
Warping deformation
Basic dimensions of castings
Error rate
≤4300
≤200
>500~800
Flatness or warping deformation
>200~500
>300~$00
>600～1200
>800~1200||tt| |>500~1200
>65~120
>1200~2000
>$1200~$2000
>$2000
After the casting is treated with water toughening, it is allowed to correct the warpage in the cold state, but the amount of warpage after correction should comply with the regulations in Table 7. Casting weight tolerance
JB/T5940-91
The casting weight tolerance shall comply with the provisions of Table B1 in Appendix B (Supplement). Its weight tolerance grade shall comply with the provisions of Table B2. 3.11 Casting draft angle
The draft angle value of the casting can refer to the provisions of Table C1 in Appendix C (Reference); the type and application of its draft angle can refer to the provisions of Table C2.
3.12 Casting surface quality
3.12.1 If there are special requirements for the surface roughness of the casting, it should be indicated in the drawing or technical documents. If not indicated, the general R. value is 100μm.
3.12.2 Clean the sand before water-toughening the casting. The pouring, riser, local protrusions, flash, etc. of the casting must be cut and leveled after water-toughening. The allowable residual height or depression shall not be greater than ±5mm. The parts that affect assembly must be leveled. 3.12.3 Without affecting the service life and performance of the casting, the defects allowed on the surface of the casting shall comply with the provisions of Table 9.
The casting defects on the surface of the casting are allowed to be repaired if they do not exceed the provisions of Table 10 and Table 11, and the repair does not affect the service life and performance of the casting.
Table 9 Defects allowed on casting surface
A (working surface)
Defect types
Sand holes, pores,
Slag holes, shrinkage holes
Wrinkles
Casting surface
A (working surface)
Defect size
≤415
Defect depth
Not more than 1/7
Wall thickness
Protrusion is not larger than
1.5mm;
Residual porosity
depth is not greater than
1/7 of the wall
Number of defects
Not more than 2 within a 450mm
circle
Not more than 1 within a 100mm
circle
Defect spacing
Defect size
B (non-working surface)
Defect depth
Not more than 1 /3
Wall thickness
Protrusion is not larger than 1.5mm,
Residual pores
depth is not large
1/3 wall
After trimming, the wall thickness should be within the size limit deviation rangeTable 10 Allowable repair of crack defects
Wall thickness of the crack surface
B (non-working surface)
A (working surface)
B (non-working surface)
Casting surface
A(working surface)
B(non-working surface)
Ratio of crack length to the length of the wall
along the crack direction
≤1/4
≤1/3
≤1/4
≤1/3
Not more than 1/2 of the wall thickness
Hole defects allowed for repair
Percentage of hole area to the surface area%
Not more than 1/3 of the wall thickness
Number of defects
Not more than 1 in a circle
Not more than 1 in a circle of $100mm
Not more than 1 in a circle of 100mm
Not more than 1 in a circle of 100mm
Defect spacing
Number of cracks on the entire casting
Number of hole defects on the entire casting
3.12.5 The defect repair of castings should be carried out after water toughening. Austenitic steel welding rods must be used for repair. 4
4 Test method
JB/T5940—91
4.1 The chemical composition of castings should be tested furnace by furnace according to the smelting furnace. The sample should be taken in the ladle or during pouring. The chemical composition analysis method shall comply with the provisions of GB223.1~223.7.
4.2 The specimens used for mechanical properties and metallographic structure shall be cast separately in the middle of pouring according to Figure 3 or Figure 4. The test block and casting shall be treated with water toughening in the same furnace, and the metallographic specimen shall be made at a distance of not less than 6mm from the surface of the test block. 155
Rough size of kiel block specimen
4.3 Mechanical property test
Figure 4 Rough size of plum blossom specimen
4.3.1 The tensile strength test shall be carried out in accordance with the provisions of GB228. 4.3.2 The impact value test shall be carried out in accordance with the provisions of GB229. 4.3.3 The Brinell hardness test shall be carried out in accordance with the provisions of GB.231. 4.3.4 The surface roughness test method of castings shall be carried out in accordance with the provisions of GB6060.1. R15
4.4 Carbide inspection: select the most serious part for evaluation in any field of view. The magnification is 500 times, 115
4.5 Inclusion inspection: Check each furnace according to the smelting furnace. Select the most serious place for evaluation in any field of view, and the magnification is 100 times; according to the shape and size of the inclusions, Grade A-inclusion diameter is about 9u, Grade B-inclusion diameter is about 15μ, and inclusions are not divided into oxides and sulfides during evaluation.
4.6 Geometric shape, size, and surface quality are inspected by visual inspection or appropriate measuring tools or relevant test methods. 5 Inspection rules
5.1 The castings shall be inspected and accepted by the supplier's quality inspection department according to the drawings, relevant technical documents and this standard, and can only be put into storage after passing the inspection. The buyer has the right to conduct random inspections and re-inspections of castings.
5.2 The following items of castings shall be inspected: chemical composition;
geometric shape and main dimensions;
surface quality;
carbide;
JB/T594091
e. Inclusions: only when the metallurgical quality cannot be guaranteed, it shall be used as an assessment inspection item. 5.3 After negotiation and confirmation between the ordering unit and the supplier, the following items may also be inspected: casting weight,
b. mechanical properties, tensile strength, elongation, impact value, hardness, etc.; c. others.
5.4 Chemical composition inspection
The chemical composition of castings shall be analyzed once per smelting furnace or per batch. The analysis results shall comply with the provisions of Table 1. 5.5 Mechanical property inspection
5.5.1 The hardness of castings shall be sampled by batch, but not less than three pieces. If unqualified castings are found during random inspection, the batch of castings shall be inspected piece by piece, and repeated heat treatment is allowed for unqualified parts. The hardness of important parts shall be inspected piece by piece. 5.5.2 The mechanical properties of castings shall be inspected furnace by furnace according to the heat treatment; random inspection is allowed for large-scale production with stable process. However, it shall not be inspected less than once every five furnaces (heat treatment furnaces). wwW.bzxz.Net
5.6 The metallographic structure of castings after water toughening shall be inspected furnace by furnace according to the heat treatment furnace. 5.7 The geometric shape and size, dimensional tolerance, machining allowance, geometric shape tolerance and surface quality of castings shall be inspected in accordance with the provisions of Articles 3.4, 3.5, 3.6, 3.9 and 3.12 respectively.
The first batch and single piece production shall be inspected piece by piece, and the castings with regular batch production and stable process shall be inspected. The inspection method shall be specified by the manufacturer in the product technical standards or ordering technical requirements according to GB2828 based on the product batch size and quality level. 5.8 Others
Other items (such as weight tolerance, etc.) shall be inspected according to the agreement between the supplier and the buyer. 6 Marking, packaging, transportation, storage
6.1 Marking and certificate
6.1.1 Each casting shall be marked with the following content or part of it on the non-machined surface: a. Factory mark;
Test batch:
Other marks required by the buyer.
When it is impossible to mark the casting, the mark can be printed on the label attached to each batch of castings. 6.1.2 The factory castings shall be accompanied by an inspection certificate; the certificate shall include the following contents: a.
Supplier name;
Casting name;
Casting drawing number or order contract number;
Manufacturing date (or number) or production batch. d.
6.2 Packaging, transportation and storage
The packaging, transportation and storage of castings shall comply with the provisions of relevant standards or order agreements. 6
JB/T5940-91
Appendix A
Machining allowance of castings
(Supplement)
The machining allowance grade of castings shall comply with the provisions of Table A1. The machining allowance of castings shall comply with the provisions of Table A2. A2
A3, for a certain casting dimensional tolerance grade in Table A1, the machining allowance grade of the top surface (relative to the pouring position) and the hole of the sand casting shall be one level lower than the machining allowance grade of the bottom and side. For example: the casting dimensional tolerance grade is CT13.The machining allowance grade of the bottom and side is MAI grade corresponding to CT13, while the machining allowance of the top and hole is MAJ grade corresponding to CT14. Table A1 Machining allowance grade of castings used in conjunction with casting dimensional tolerances Production method
Casting conditions
Dimension tolerance grade CT
Machining allowance grade MA
Dimension tolerance grade CT
Machining allowance grade MA
Basic dimensions
Sand mold hand molding
Batch and large plate production
Casting process method
Sand mold machine molding and shell mold
Investment casting
Small batch and single piece production
Moulding material
Dry and wet sand
Machining allowance of castings used in conjunction with casting dimensional tolerances 6
Self-hardening Sand
Dimension tolerance grade CT
Machining allowance grade MA
Basic size
Dimension tolerance grade CT
Machining allowance grade MA
Basic size
JB/T5940—91
Continued table A2
Dimension tolerance grade C1
Machining allowance grade MA
Basic size
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Continued table A2
Note: Each column in the table has two machining allowance values. The upper value is the machining allowance value for single-sided machining based on one side, and the lower value is the machining allowance value for each side when double-sided machining is performed.
JB/T594091
Appendix B
Tolerance of casting weight
(Supplement)
B1 The weight tolerance of castings shall comply with the provisions of Table B1. Table B1
Nominal weight
Tolerance of casting weight
Weight tolerance grade
Note: The weight tolerance value in the table is equal to the absolute value of the algebraic difference between the upper deviation and the lower deviation. That is, the weight tolerance grade of the casting shall comply with the provisions of Table B2. MT
Half is the upper deviation, and the other
half is the lower deviation. The weight tolerance shall be selected in accordance with the size tolerance. For example: the size tolerance is CT13, and the weight tolerance is MT10. Table B2 Weight tolerance grade of castings
Production method
Casting conditions
Weight tolerance grade MT
Sand mold hand molding
Batch and mass production
Casting process method
Sand mold machine molding and shell mold
Investment casting
Small batch and single piece production
Moulding material
Self-hardening sand
Dry and wet sand
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