1. Main application:
Large, precision, high polishing plastic moulds, such as car accessories, household appliance, electronic and Audio/Video products.
2. Manufacturers:
An Steel, Tai Steel, Wuyang Steel,
3. Delivery conditions:
Conventional or ESR, hot rolling or forging, black surface or milling
Hardened and tempered to: 28~35HRC
4. General
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 1.2738 contain additional quantities of Ni and no additional quantities of S.
5. Chemical analysis:
|
C% |
Mn% |
Si% |
Cr% |
Ni% |
Mo% |
P% |
S% |
|
0.32~0.40 |
1.10~1.50 |
0.20~0.40 |
1.10~2.00 |
2.90~3.50 |
0.25~0.40 |
=<0.03 |
=<0.03 |
6. Mechanical properties:
Low sulphur plastic mould steel that is usually supplied in a quenched and tempered condition. The additional Ni content improves the through hardenability large dimensions (>400 mm). Good machinability, better polishability compared to 1.2312 (AISI P20+S). Similar to AISI P20+Ni.
7. Available sizes:
Round Bar: Φ 6-410mm
Flat: 8-160*205-710mm
Plate: 20-400mm*1800-3200mm (Thickness*Width)
Mould: 200*200-1200*1000mm
Length: 3000-12000mm
Mill deliver conditions, or sawing or cutting for customer request.
8. Compared grades:
|
Chinese |
American |
German |
Swedish |
Japanese |
DIN EN |
|
GB |
AISI |
DIN |
ASSAB |
JIS |
ISO 4957 |
|
3CrMnNiMo |
P20+Ni |
1.2738 |
718 |
NAKS5 |
40CrMnNiMo |
|
Grade |
Standard |
C |
Si |
Mn |
Cr |
Mo |
Ni |
P、S≤ |
|
718 |
ASSAB |
0.32-0.40 |
0.20-0.40 |
1.10-1.50 |
1.70-2.00 |
0.25-0.40 |
0.85-1.15 |
0.030 |
|
1.2738 |
DIN |
0.35-0.45 |
0.20-0.40 |
1.30-1.60 |
1.80-2.10 |
0.15-0.25 |
0.90-1.20 |
0.030 |
|
3Cr2MnNiMo |
GB |
0.32-0.40 |
0.20-0.40 |
1.10-1.50 |
1.70-2.00 |
0.25-0.40 |
0.85-1.15 |
0.030 |
9. Physical properties:
|
Thermal expansion coefficient |
10 |
20 |
20-200°C |
20 |
20 |
|
m K |
11.8 |
12.5 |
13.1 |
13.3 |
|
|
Thermal conductivity |
W |
20°C |
|
|
|
|
m K |
39.5 |
39.1 |
|
|
10. Heat treatment:
|
Soft annealing |
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 |
|