DIN 1.2738 steel
DIN 1.2738 steel is one kind of plastic mold steel, equivalent to AISI P20+Ni tool steel. While Nickel, chromium and molybdenium are the alloying elements for hardness and toughness. 1.2738 tool steel is specially designed for plastic mold industry, especially for big steel mold parts.
- DIN 1.2738 tool steel is usually supplied as pre-hardened/quenched and tempered 280 – 320 HB hardness condition
- With good machinability, DIN 1.2738 steels is with better polishability compared to 1.2312 (AISI P20+S).
- Material 1.2738 can be through nitrogenation and flame hardening treatment in order to increase the hardness and wearability of mould surface.
- The steel 1.2738 is melted in an electrical furnace and refined with VOD or DH device.
1. Supply Range of 1.2738 steels
Round Bar: diameter 20mm – 1000mm
Steel Plate and Steel Block: thickness 12-500mm x width 200-2000mm
Surface Finish: Black Surface, Roughly Machined, Peeled & Turned or as per given requirements.
2. DIN 1.2738 Mold Tool Steel Properties
- Physical properties at ambient temperature
Modulus of elasticity [103 x N/mm2]: 205
Density [g/cm3]: 7.80
Thermal conductivity [W/m.K]: 29.0
Specific heat capacity[J/g.K]: 0.46
Strength:≈ 1080 N/mm²
Thermal Conductivity at 100 °C:33.5 W/m K
3. Forging of 1.2738 Tool Steel
Hot forming temperature: 1093-898 °C.
4. Heat Treatment of Mold Steel 1.2738
- Heat Treatment of 2738
Usually already pre-toughened, no heat treatment required, if there is no special requirements.
- Soft annealing,
710 to 740 °C for about 2 to 5 hours; then cool slowly of 10 to 20 °C per hour to about 600 °C further cooling in air, This will produce a maximum Brinell hardness of 235.
- Hardening:
Harden from a temperature of 840-870°C followed by oil, then quenching in oil/hot bath/air 180~220 °C. Hardness after quenching is around 52 HRC.
- Tempering of material
Slow heating to tempering temperature immediately after hardening; and minimum time in furnace: 1 hour per 20 mm part thickness; tempering twice is recommended.
5. Applications of DIN 1.2738 Steel
1.2738 mold steel materials are generally used for relatively low temperature applications such as die casting dies and injection moulds, synthetic plastic moulds dies, especially for large plastic moulds higly stressed in core, hydroforming tools, such as up to 400 mm in the construction of plastic moulds. DIN 1.2738 is suitable for nitriding and chrome plating.
| Country / Standard | Standard Designation | Grade |
|---|---|---|
| Germany (DIN) | DIN EN ISO 4957 | 1.2738 |
| USA (ASTM/AISI) | ASTM A681 | P20+Ni |
| Japan (JIS) | JIS G 4404 | PX5 / PDS5 |
| Grade | C (%) | Mn (%) | P (max) | S (max) | Si (%) | Cr (%) | Mo (%) | Ni (%) |
|---|---|---|---|---|---|---|---|---|
| 1.2738 | 0.35 - 0.45 | 1.30 - 1.60 | 0.030 | 0.030 | 0.20 - 0.40 | 1.80 - 2.10 | 0.15 - 0.25 | 0.90 - 1.20 |
| Grade | C (%) | Mn (%) | P (max) | S (max) | Si (%) | Cr (%) | Mo (%) | Ni (%) |
|---|---|---|---|---|---|---|---|---|
| P20+Ni | 0.28 - 0.40 | 0.60 - 1.00 | 0.030 | 0.030 | 0.20 - 0.80 | 1.40 - 2.00 | 0.30 - 0.55 | 0.90 - 1.20 |
Type: Prehardened plastic mold steel
Delivery Condition: Prehardened to 280-325 HB (approx. 30-34 HRC)
Key Characteristics: Excellent polishability, good corrosion resistance, high toughness, good machinability
Typical Applications: Large plastic injection molds, die casting dies, extrusion tools, mold bases
| Property | Value | Unit |
|---|---|---|
| Density | 7.85 | g/cm³ |
| Thermal Expansion (20-200°C) | 11.5 | 10⁻⁶/°C |
| Thermal Conductivity (20°C) | 29.0 | W/m·K |
| Modulus of Elasticity | 205 | GPa |
| Property | Value | Unit |
|---|---|---|
| Hardness (Prehardened) | 280 - 325 | HB |
| Tensile Strength | 950 - 1050 | MPa |
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