In the DIN EN ISO 4957 the grades 1.2311 (AISI P20), 1.2312(AISI P20+S) and 1.2738 (AISI P20+Ni) covered by the above mentioned code were amalgamated. The grade 1.2312 contain additional quantities of S and no additional quantities of Ni.
1. Applications:
Plastic moulds, frames for plastic pressure dies, hydroforming tools.
2. Chemical analysis:
|
C%
|
Mn%
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Si%
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Cr%
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Mo%
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P%
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S%
|
|
0.35~0.45
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1.40~1.60
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0.30~0.50
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1.80~2.00
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0.15~0.25
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=<0.03
|
0.05-0.10
|
3. Steel properties:
Plastic mould steel with additional sulphur, usually supplied in a quenched and tempered condition. Polishable, better machinibility compared to 1.2311. Similar to AISI P20+S.
4. Condition of delivery:
Quenched and tempered, 950 - 1100 N/mm²
5. Physical properties:
|
Thermal expansion coefficient
|
10-6 m
|
20-100°C
|
20-200°C
|
20-300°C
|
20-400°C
|
|
m K
|
12.3
|
12.9
|
13.3
|
13.5
|
|
|
Thermal conductivity
|
W
|
20°C
|
350°C
|
|
|
|
m K
|
39.6
|
39.3
|
|
|
6. Heat treatment:
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Soft annealing
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Temperature
|
Cooling
|
Hardness
|
|
710 - 740°C
|
furnace
|
max. 235 HB
|
|
|
|
|||
|
Stress relief annealing
|
Temperature
|
Cooling
|
|
|
500 - 550°C
|
furnace
|
|
|
|
|
|||
|
Hardening
|
Temperature
|
Cooling
|
Tempering
|
|
830 - 870°C
|
oil or hot bath
180 - 220°C
|
see tempering
diagram
|
|
