Cold work tool steel
ALTA A8 Tool Steel Specification
Steel properties
ALTA A8 steel is a medium carbon, air-hardening tool steel that is characterized by a combination of very good toughness, intermediate wear resistance, and excellent dimensional stability in heat treatment. It has been used for punches that operate in the 55 to 60 Rockwell C hardness range. Better toughness than A2 or D2 steel, and higher wear resistance than S7 steel, its deformation is very stable in heat treatment.
Applications
² Commonly used in the production of cutting tools in the fields of papermaking, wood processing, sugar making, etc. Others tools like forming rollers, punches, chuck jaws, precision stamping dies… etc.
Chemical composition
Chemical Composition per %
|
C |
Si |
Mn |
P |
S |
Cr |
Mo |
W |
Ni |
Cu |
Min. |
0.50 |
0.75 |
0.20 |
|
|
4.75 |
1.15 |
1.00 |
|
|
Max. |
0.60 |
1.10 |
0.50 |
0.030 |
0.030 |
5.50 |
1.65 |
1.45 |
0.25 |
0.30 |
Basic melting process : |
IM/EAF + LF + VD + (ESR) |
Hardness : |
Max 240 HB (annealed) |
Reduction ratio : |
5 : 1 minimum or required |
Grain size : |
≥ 6.0 per ASTM E112 |
Non-metallic inclusion : |
≤ 1.0 (thick), ≤ 1.5 (thin) per ASTM E45 method A (more pure by ESR route) |
Ultrasonic Test |
SEP1921, , EN 10308, ASTM A388 or agreed methods |
Macro-structure |
As per ASTM E381 |
Straightness / flatness |
≤ 1.5 mm / m (machined), ≤ 2.5 mm / m (black) |
Tolerance |
Per discussed |
Size range (round bars) |
Ø 12 - 500 mm |
Size range (flats, plates) |
8 - 400 mm in thickness max. 1100 mm in width |
Heat treatment
Annealing |
Temperature(°C) |
Hardness |
830 - 845 |
max. 240 HB |
Hot-forming |
Temperature(°C) |
1090 - 1150 |
Hardening and tempering |
Quenching temperature(°C) |
Quenching medium |
Frequently-used tempering temperature(°C) |
995 - 1010 |
Oil or air-cooled |
150 - 590 |
Recommended solid carburizing heat treatment process:
Preheating for 1.5h to 650°C, holding for 0.5h, carburizing for 1.5h to 1010°C, holding for 0.5h, air cooling. Hardness reached 862HV.
Downloads
-
2024-06-25 Alta A8 SPEC (011 - S6 - T2 ).pdf
끂35 245.87 KB
Features
² High toughness
² Intermediate wear resistance
² Excellent dimensional stability
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