Plastic Mould Steel
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| M238 Bohler M238: Equivalent* 1.2738, P20+Ni, PX4, HPM7 |
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Chemical composition (average %)
| C | Si | Mn | Cr | Mo | Ni | |
| M238 | 0.38 | 0.30 | 1.50 | 2.00 | 0.20 | 1.10 |
Material characteristic and use
| Properties | The hardened and tempered plastic mould steel. Because of the Ni-addition there is no hardness decrease in the center of large sizes over 400 mm thickness. (see Quantitative phase diagramm). A special melting technology offers good machinability. |
| Application | Large moulds (over 400 mm thickness) for plastics processing, mould carrier frames for the plastic moulds, components for general mechanical engineering and tool manufacture. |
| As-supplied condition | Hardened and tempered to approx. 1000 N/mm3 (approx. 28- 32 HRC). General, no heat treatment required. If heat treatment is carried out for special purposes, e.g. for obtaining an increase in strength, the following instructions should be observed. |
Physical characteristics
| Temperature | |||||||||
| 20 ºC | 100 ºC | 200 ºC | 300 ºC | 400 ºC | 500 ºC | 600 ºC | 700 ºC | ||
| Density | (kg/dm3) | 7.85 | |||||||
| Thermal conductivity | W/(m·K) | 33.0 | 33.5 | 33.5 | 33.5 | 33.5 | |||
| Specific heat | J/(kg·K) | 460 | |||||||
| Electrical resistivity | Ohm·mm2/m | 0.19 | |||||||
| Modulus of elasticity | N/mm2 | 210x103 | |||||||
| Thermal expansion | 10-6m/(m·K) | 12.8 | 13.0 | 13.8 | 14.0 | 14.2 | 14.2 | 14.5 | |
* Chemical composition is only reference and might not be the same
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