2311 Plastic Mould Steel
DIN 1.2311 (40CrMnMo7) · AISI P20 · GB 3Cr2Mo
DIN 1.2311 (commonly referred to simply as "2311") is a pre-hardened chromium-manganese-molybdenum plastic mould steel that has become one of the most widely used grades in injection mould tooling worldwide. Its most commercially significant feature is that it is supplied in the pre-hardened condition (280–320 HB, equivalent to 28–34 HRC) — meaning that moulds can be machined directly to final dimensions without any subsequent hardening or heat treatment.
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Material Properties
In the pre-hardened condition, 2311 exhibits a uniform hardness of 280–320 HB (approximately 28–34 HRC) throughout the cross-section. Machinability is good — typical cutting speeds for carbide tooling are 80–120 m/min. The steel has adequate polishability for general industrial mould applications, though it does not reach the mirror-finish capability of higher-purity grades like 2738 or TGP80. Weldability is acceptable with appropriate preheating (200–250°C). The alloy composition provides sufficient corrosion resistance for normal indoor toolroom environments.
This pre-hardened delivery condition dramatically simplifies the mould manufacturing workflow: it eliminates the risk of distortion or dimensional change during heat treatment, removes the need for costly heat treatment operations after machining, and ensures predictable machinability throughout the entire block. For mould shops producing medium-complexity injection tools where optical-quality surface finish is not required, 2311 is typically the most cost-effective choice.
PT. Precision Special Steel supplies 2311 in plate form in a range of thicknesses. The plates are produced to consistent through-hardness, ensuring uniform machinability regardless of machining depth.
Chemical Composition (%)
| Element | Content (%) |
|---|---|
| C | 0.28 – 0.40 |
| Si | 0.20 – 0.80 |
| Mn | 1.40 – 2.00 |
| Cr | 1.80 – 2.10 |
| Mo | 0.30 – 0.55 |
| P | ≤ 0.030 |
| S | ≤ 0.030 |
Mechanical Properties
| Property | Value |
|---|---|
| Hardness (Supply Condition) | 280 – 320 HB (28 – 34 HRC) |
| Tensile Strength | 965 – 1 100 MPa |
| Yield Strength (0.2%) | 825 – 960 MPa |
| Impact Toughness (KU2) | ≥ 63 J |
| Density | 7.85 g/cm³ |
Typical Applications
Frequently Asked Questions
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What are the international standard equivalents for 2311?
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Plastic Mould Steel
Related Grades
Other grades in the same product family that may suit your application.
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2738
Plastic Mould Steel
Enhanced pre-hardened plastic mould steel with nickel addition for improved through-hardness in large sections, better polishability, and superior toughness versus 2311.
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TGP80
★Plastic Mould Steel
Tiangong's exclusive premium plastic mould steel, pre-hardened to 38–42 HRC with exceptional mirror polishability for optical and high-gloss injection mould applications.
View Details →Need 2311 in Indonesia?
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