GB/T 35840.3-2018 in English
VALIDSteels for plastic mould—Part 3:Corrosion resistant steels
- Issued on:2018-05-14
- Implemented on:2019-02-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$136.00
《GB/T 35840.3-2018塑料模具钢 第3部分:耐腐蚀钢》由TC183（全国钢标准化技术委员会）归口，TC183SC16（全国钢标准化技术委员会特殊钢分会）执行，主管部门为中国钢铁工业协会。
本部分规定了耐腐蚀塑料模具钢的订货内容、尺寸、外形、重量、技术要求、试验方法、检验规则、包装、标志及质量证明书等。
本部分适用于制造塑料模具用热轧、锻制及机加工交货的耐腐蚀圆钢、方钢、扁钢（以下简称钢材）。
Introduction
1. Background and significance of standard formulation
GB/T 35840.3-2018 "Plastic mold steel Part 3: Corrosion-resistant steel" is an important standard for the field of plastic mold manufacturing. It mainly regulates the technical requirements, chemical composition and test methods of corrosion-resistant steel. With the rapid development of the plastic mold industry, higher requirements are put forward for the corrosion resistance and processing performance of mold materials. The formulation of this standard provides clear technical guidance and quality assurance for the industry.
2. Analysis of the main contents of the standard
2.1 Scope and applicability
This part is applicable to hot-rolled, forged and machined corrosion-resistant round steel, square steel and flat steel for the manufacture of plastic molds. Its chemical composition and performance requirements must meet the requirements of Table 1, including the content range of elements such as Cr, Mo and Ni.
2.2 Chemical composition and performance requirements
| Serial number | Uniform digital code | Grade | C(%) | Si(%) | Mn(%) | Cr(%) | Mo(%) | Ni(%) | V(%) |
|---|---|---|---|---|---|---|---|---|---|
| 1 | S42043 | 4Cr13 | 0.36~0.45 | ≤1.00 | ≤0.80 | 12.00～14.00 | - | - | - |
| T25444 | 4Cr13NiVSi | 0.36～0.45 | 0.90～1.20 | 0.40～0.70 | 13.00～14.00 | 0.15～0.30 | 0.25~0.35 |
2.3 Corrosion resistance and application cases
Corrosion-resistant steel is mainly used in mold manufacturing for injection molds in highly corrosive environments, such as the production of electronic products and household appliances. Taking 4Cr13 as an example, its excellent corrosion resistance and good processing performance make it an ideal material for manufacturing precision molds.
3. Comparison of standard frameworks and technological evolution
3.1 Comparison of domestic and foreign standards
| Dimensions | Domestic standards | International standards | Difference analysis |
|---|---|---|---|
| Chemical composition requirements | GB/T 35840.3 | ISO international standards | Domestic standards are more stringent, especially the range of Cr and Ni content. |
| Test Methods | GB/T 223 Series | ASTM/EN Standards | Domestic standards focus more on operability in practical applications. |
3.2 Analysis of Technology Evolution
In recent years, the technological development of corrosion-resistant steel has focused on improving the corrosion resistance and processing performance of materials. By improving smelting processes and heat treatment technologies, new corrosion-resistant steels (such as 3Cr17Mo) have better mechanical strength while maintaining high corrosion resistance.
4. Implementation Suggestions and Precautions
4.1 Suggestions for Selecting Standards
- Choose the appropriate grade according to the working environment of the mold. For example, when corrosion is severe, steel containing Ni and V should be given priority.
- Specify the chemical composition, delivery status and hardness requirements when ordering.
4.2 Quality Control Recommendations
Manufacturers should strengthen the detection of low-magnification structures and non-metallic inclusions to ensure that the internal quality of the material meets the standard requirements. At the same time, a complete heat treatment process system should be established to ensure stable performance after annealing and quenching.
4.3 Precautions in Application
During the mold processing process, excessive processing should be avoided to cause surface damage. It is recommended to use appropriate surface treatment technology (such as electroplating or hot-dip plating) to further improve corrosion resistance.
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