Heavy Mechanical General Techniques and Standards - Part 6: Steel Castings
1 Scope
This part of JB/T 5000 specifies the technical requirements, test methods. inspection rules, marks and packing of the carbon and low alloy steel castings for heavy machinery.
This part is applicable to the carbon and low alloy steel castings cast in sand mould or the casting mould with equivalent thermal conductivity with the sand mould.
This part is not applicable to such special steel grades as high manganese steel, heat-resistant steel and stainless steel.
2 Normative References
The following normative documents contain provisions which, through reference in this part of JB/T 5000, constitute provisions of this part. For dated reference, subsequent amendments to, or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this part are encouraged to study whether the latest editions of these documents are applicable. For undated references, the latest edition of the normative document referred to applies.
GB/ T 222 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 223 (all) Methods for Chemical Analysis of Iron, Steel and Alloy
GB/T 228 Tensile Test Methods on Metal (GB/T 228-2002, eqv ISO 6892: 1998)
GB/T 229 Metallic Materials - Charpy Notch Impact Test (GB/T 229-1994, eqv ISO 148: 1983)
GB/T 231.1 Metallic Materials - Brinell Hardness Test [GB/T 231.I- 2002, eqv ISO 6506-1: 1999 (E)]
GB/T 6060.1 Roughness Comparison Specimens Cast Surfaces (GB/T 6060.1-1997, eqv ISO 2632-3: 1979)
GB/T 6414-1999 Castings - System of Dimensional Tolerances and Machining Allowances (eqv ISO 8062: 1994)
GB/T l5056 Evaluation Method on Cast Surface Roughness
JB/T 5000.7 Heavy Mechanical General Techniques and Standards - Part 7: Repair Welding for Steel Castings
JB/T 5000.12 Heavy Mechanical General Techniques and Standards - Part 12: Paint
JB/T 5000.13 Heavy Mechanical General Techniques and Standards - Part 13: Packing
JB/T 5105 Pattern Draft of Casting Form
JB/T 6397-2006 Specification for the Heavy Carbon Structural Steel Forgings
3 Technical Requirements
3.1 Grade, chemical composition and mechanical property
3.1.1 The grade, chemical composition and mechanical property of carbon steel shall be in accordance with those specified in Tables 1 and 2.
3.1.2 The grade, chemical composition and mechanical property of low-alloy steel shall be in accordance with those specified in Tables 3 and 4.
3.2 Surface quality
3.2.1 The sand fusion, sand inclusion, flash, burr, gating and risering and the oxide coating on the castings shall be removed cleanly.
3.2.2 The roughness of cast surface shall be in accordance with those specified in Table 5.
Table 1 Chemical Composition of Carbon Steel
Material grade Mass fraction(%) ≤
C Si Mn S P Residual element
Ni Cr Cu Mo V
ZG200-400 0.20 0.50 0.80 0.04 0.04 0.30 0.35 0.30 0.20 0.05
ZG230-450 0.30 0.90
ZG270-500 0.40
ZG310-570 0.50 0.60
ZG340-640 0.60
NOTE 1: Each grade may be added with 0.04% of manganese when reducing per 0.01% of carbon, manganese of ZG 200-400 shall be 1.00% at most, that of the rest four grades shall be 1.20% at most.
NOTE 2: The gross amount of residual element shall not be larger than 1.00%. The residual elements may not be analyzed if not required by the buyer.
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Table 2 Mechanical Property of Carbon Steel
Material grade Mechanical property≥
Yield point or yield strength
MPa Tensile strength MPa
Elongation
% Shrinkage factor
% Impact absorbing energy
J
J
ZG200-400 200 400 25 40 30 47
ZG230-450 230 450 22 32 25 35
ZG270-500 270 500 18 25 22 27
ZG310-570 310 570 15 21 15 24
ZG340-640 340 640 10 18 10 16
NOTE 1: The supplier may choose any one from and if not required by the buyer.
NOTE 2: The properties of each grade listed in the above table are applicable to the castings with thickness not larger than 100mm. And the yield strength specified in the table are only for design reference if the thickness of casting is larger than 100mm.
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Foreword I
1 Scope
2 Normative References
3 Specifications
3.1 Grade, chemical composition and mechanical property
3.2 Surface quality
3.3 Repair welding
3.4 Dimensional tolerance
3.5 Finishing allowance
3.6 Weight deviation
3.7 Pattern draft
3.8 Tortuosity ratio
4 Test Methods and Test Rules
4.1 Chemical analysis
4.2 Mechanical test
4.3 Surface inspection
4.4 Dimension inspection
5 Marks and Packing
5.1 Marks and quality certificate
5.2 Painting and packing
Figure 1 Dimensional Tolerance and Extreme Dimension
Figure 2 Maximal Shifting
Figure 3 Maximal Overall dimension of Finished Casting after Final Mechanical Processing
Figure 4 Cast Steel Disc
Figure 5 Single-cast Test Block for Mechanical Property
Table 1 Chemical Composition of Carbon Steel
Table 2 Mechanical Property of Carbon Steel
Table 3 Chemical Composition of Low-alloy Steel
Table 4 Mechanical Property of Low-alloy Steel
Table 5 Roughness of Cast Surface
Table 6 Cutting Surplus of Casting Head
Table 7 Dimensional Tolerance Value of Casting
Table 8 Finishing Allowance
Table 9 Blank Dimension of Cast Steel Disc
Table 10 Weight Deviation of Casting
Table 11 Tortuosity Ratio of Casting
