Hot work tool steel
ALTA 1.2581 Tool Steel Specification
Steel properties
ALTA 1.2581 steel is a kind of ~ 8% W (tungsten) hot work tool steel, due to its high W% composition, it have high hot hardness (red hardness) and strength even at a high temperature. Medium hardenability, and poor performance of toughness and plasticity.
Suitable for making hot stamping dies, upsetting dies, die-casting dies, etc require high hardness at high temperature/high stress, but not subject to much impact loads (working temperature up to ~ 650 – 700°C).
Applications
² Die-casting mold (mold core, insert, mold core, diverter cone, nitrided ejector pin)
² Copper alloy extrusion die
² Die casting mold
Chemical composition
Chemical Composition per %
|
C |
Si |
Mn |
P |
S |
Cr |
W |
V |
Ni |
Cu |
Min. |
0.25 |
0.15 |
0.15 |
|
|
2.50 |
8.50 |
0.30 |
|
|
Max. |
0.35 |
0.40 |
0.45 |
0.020 |
0.010 |
3.20 |
9.50 |
0.50 |
0.25 |
0.25 |
Basic melting process : |
IM/EAF + LF + VD + ESR (EFS-annealing) |
Hardness : |
Max 241 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) |
Microstructure | SEP1614 or NADCA # 207 |
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. 1000 mm in width |
Heat treatment
Annealing |
Temperature(°C) |
Hardness |
740 - 780 |
max. 241 HB |
Hot-forming |
Temperature(°C) |
850 - 1100 |
Hardening and tempering |
Quenching temperature(°C) |
Quenching medium |
Frequently-used tempering temperature(°C) |
1140 - 1160 |
Oil |
590 - 610 |
Ac1 | Accm | Ar1 | Arcm | Ms |
820 | 925 | 773 | 838 | 380 |
Elastic modulus : E ( N/mm2 )
Temperature °C | Room 20 | 100 | 200 | 300 |
E | 22600 | 22200 | 21600 | 20800 |
Modulus of rigidity / Shear modulus of elasticity : G ( N/mm2 )
Temperature °C | Room 20 | 100 | 200 | 300 |
G | 8600 | 8490 | 8260 | 7930 |
Ratio of elastic modulus to shear modulus :
Temperature °C | Room 20 | 100 | 200 | 300 | Average ratio |
E : G | 2.6279 | 2.6148 | 2.6150 | 2.623 | 2.6202 |
Coefficient of thermal conductivity : λ W/(m·K)
Temperature °C | 100 | 200 | 700 | 900 |
λ | 20.09 | 22.19 | 24.28 | 23.03 |
Resistivity : ρ(Ω·m)
Temperature °C | Room 20 | 200 | 500 | 700 | 900 |
P x 10-6 | 0.50 | 0.60 | 0.80 | 1.00 | 1.19 |
Coefficient of linear expansion : α(mm/(mm·°C))
Temperature °C | 20~400 | 20~500 | 20~600 | 20~700 |
Αx 10-6 | 12.00 | 12.60 | 12.90 | 13.60 |
SPecific heat [capacity] : Cp (J/Kg·K)
Temperature °C | 20-100 | 20-200 | 20-300 |
Cp x 103 | 0.465 | 0.473 | 0.478 |
Poisson-ratio : μ
Temperature °C | Room 20 | 100 | 200 | 300 |
μ | 0.31 | 0.31 | 0.31 | 0.31 |
Oxidation resistance : (test sample hardness 48.8-49.1 HRC), + g/m2
h | 2 | 7 | 15 | 25 | 35 | 45 | 60 | 80 | 125 | 150 |
600 °C | 2.4 | 4.2 | 8.1 | 11.6 | 14.1 | 16.6 | 20.2 | 22.7 | 30.2 | 34.6 |
h | 2 | 5 | 15 | 25 | 35 | 45 | 55 | 65 | 80 | 100 |
700 °C | 5.7 | 11.4 | 24.7 | 35.9 | 49.5 | 55.9 | 66.3 | 75.3 | 87.5 | 100.5 |
h | 2 | 5 | 8 | 11 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 |
750 °C | 8.5 | 15.1 | 24.8 | 33.6 | 44.3 | 56.0 | 67.5 | 77.6 | 88.3 | 99.1 | 109.5 | 121.1 |
h | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 |
800 °C | 13.5 | 23.1 | 32.8 | 45.7 | 59.1 | 74.1 | 87.0 | 98.2 | 11.3 | 122.9 | 136.7 | 148.5 |
h | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
850 °C | 17.3 | 31.4 | 47.2 | 67.3 | 86.5 | 100.4 | 113.0 | 135.4 | 151.5 | 167.3 |
h | 1 | 2 | 3 | 4 |
1000 °C | 100.3 | 226.7 | 401.2 | 563.5 |
Thermal stability (-HRC) (A=48.8-49.1 HRC, B=42.0-43.0 HRC, h=soaking time - hours)
(1) 620°C
h | 0 | 2 | 4 | 6 | 8 | 11.5 | 14.5 | 17.5 | 21 |
A | 49.4 | 47.0 | 46.0 | 45.2 | 44.7 | 42.8 | 42.7 | 41.1 | 39.5 |
B | 43.5 | 42.8 | 41.6 | 41.6 | 41.0 | 39.5 | 39.4 | 38.1 | 37.6 |
(2) 640°C
h | 0 | 2 | 4 | 6 | 8 | 11 | 14 | 17 |
A | 49.3 | 45.1 | 42.2 | 40.0 | 39.6 | 38.0 | 36.7 | 34.3 |
B | 44.6 | 42.3 | 39.7 | 38.5 | 38.3 | 36.5 | 35.2 | 34.0 |
(3) 660°C
h | 0 | 1 | 2 | 3 | 5 | 7 | 9 | 12 |
A | 47.5 | 44.1 | 40.8 | 39.6 | 37.0 | 34.7 | 33.0 | 32.0 |
B | 42.8 | 41.1 | 37.9 | 37.0 | 35.5 | 33.3 | 32.5 | 30.7 |
(4) 680°C
h | 0 | 0.5 | 1 | 1.5 | 2 | 3 | 4 |
A | 48.3 | 45.0 | 41.5 | 39.0 | 36.3 | 34.3 | 34.1 |
B | 41.9 | 40.1 | 37.9 | 35.9 | 34.6 | 32.3 | 31.5 |
(5) 700°C
h | 0 | 0.5 | 1 | 1.5 | 2 | 3 |
A | 49.1 | 40.2 | 36.6 | 33.7 | 32.7 | 30.9 |
B | 42.8 | 36.6 | 35.0 | 32.6 | 31.8 | 30.3 |
Downloads
-
2024-06-12 Alta 1.2581 SPEC (011 - S6 - T2 ).pdf
끂68 317.4 KB
Features
² High hot hardness (red hardness)
² High thermal fatigue resistance
² High hot strength
² Good resistance to heat cracking
² High polishability and machinability
² Poor toughness and plasticity
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