Hot work tool steel
ALTA GW650(TM) Tool Steel Specification
Steel properties
ALTA GW650 steel is a new type of high-strength and toughness hot forging die steel developed on the basis of foreign standard steels AISI H10 and GOST 3X3M3Ф series steels. It is developed to meet the needs of a large number of difficult-to-deform alloy forgings, high-temperature alloy forgings and precision forgings for aviation jet engines.
The addition of trace element Nb makes the steel have higher tempering resistance, thermal strength and obvious secondary tempering effect. The disadvantage of this steel is that it has a tendency to decarburize.
Compared with the word widely used H13 steel, the performance of GW650 steel is that when the working temperature of the mold cavity surface :
1) 700°C, the values of δ b and δ s of GW650 are 2.5 and 2.8 times of H13
2) 620°C and 640°C, based on HRC40 and HRC44, the time that GW650 steel can last for is twice that of H13.
( δ b - tensile strength, δ s - yield strength)
GW650 steel working temperature is unfavorable exceed 650 °C.
Applications
² Used on various forging equipment, die-casting machines, aluminum extrusion machines and hydraulic presses weighing thousands of tons
² Production of various alloy structural steels, stainless steels, titanium alloys, nickel-based alloys, non-ferrous metal forgings or die castings
² Roll forging mould for connecting rod
Chemical composition
Chemical Composition per %
|
C |
Si |
Mn |
Cr |
Mo |
V |
Nb |
Avg. |
0.25 |
|
|
3.00 |
3.00 |
0.90 |
|
Basic melting process : |
IM/EAF + LF + VD + ESR |
Hardness : |
Max 229 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) |
Micro-structure | 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 - 600 mm |
Size range (flats, plates) |
8 - 500 mm in thickness max. 1100 mm in width |
Heat treatment
Annealing |
Temperature(°C) |
Hardness |
850 - 870 |
max. 229 HB |
Hot-forming |
Temperature(°C) |
900 - 1120 |
Hardening and tempering |
Quenching temperature(°C) |
Quenching medium |
Frequently-used tempering temperature(°C) |
950 - 1100 |
Oil |
450 - 650 |
**570~600°C tempering x 2h, air-cooled, hardness 47~49HRC
**600~630°C tempering x 2h, air-cooled, hardness 42~47HRC
Ac1 | Accm | Ar1 | Arcm | Ms |
825 | 920 | 734 | 810 | 355 |
Downloads
-
2024-08-05 Alta GW650(TM) SPEC (001 - S3 - T1).pdf
끂35 340.32 KB
Features
² High hot and cold fatigue resistance
² High red hardness
² High hot strength
² High hot stability (compared data with H13 steel, see figure 1)
² High toughness
Figure 1 – Hot stability of GW650 and H13 (HRC)
Temperature/ Time |
620°C | 640°C | ||||
Grade | 2h | 4h | 11h | 2h | 4h | 11h |
GW650 | 46.3 | 44.0 | 40.6 | 43 | 40.2 | 33.6 |
H13 | 43.1 | 42.30 | 38.0 | 40.2 | 37.4 | 32.0 |
Figure 1-1 – Hot stability of GW650 and 3Cr2W8V(~H21/1.2581) (HRC) at 650°C
Time\ Grade |
0 | 20' | 40' | 1h | 2h | 4h | 5h |
3Cr2W8V | 49.2 | 46.5 | 44.0 | 41.7 | 39.9 | 36.1 | 34.8 |
GW650 | 49.5 | 49.1 | 47.8 | 46.9 | 44.8 | 41.6 | 40.2 |
** 3Cr2W8V steel quenching at 1150°C, tempering at 500°C x 1h x 3 times, air-cooled
** GW650 steel quenching at 1080°C, tempering at 590°C x 3h, 580°C x 3h, oil-cooled
Mechanical properties:
Figure 2 – Examples of hot die steel’s mechanical properties under high temperature
Grade | 600°C | 650°C | 700°C | |||||||||
Бb Mpa |
Бs Mpa |
δ % |
ψ % |
Бb Mpa |
Бs Mpa |
δ % |
ψ % |
Бb Mpa |
Бs Mpa |
δ % |
ψ % |
|
5CrNiMo | 313 | 262 | 69.0 | 91.1 | 177 | 142 | 101 | 96.1 | 99.0 | 76.0 | 105.9 | 96.4 |
H13 | 946 | 834 | 20.5 | 72.9 | 620 | 556 | 24 | 83.2 | 198 | 160 | 53.4 | 98.8 |
3Cr2W8V | 1104 | 959 | 11.2 | 15.4 | 808 | 718 | 5.4 | 415 | 364 | 26.6 | 70.8 | |
GW650 | 1104 | 922 | 11.3 | 40.7 | 855 | 745 | 8.8 | 22.5 | 489 | 448 | 19.2 | 81.9 |
Figure 3 – Examples of hot die steel’s impact toughness (ak-cm2)
Temperature\ Grade |
20°C | 200°C | 250°C | 300°C | 350°C | 400°C |
5CrNiMo | 6.08 | 21.36 | 22.16 | 24.22 | 22.56 | 22.07 |
4Cr5W2VSi | 14.61 | 30.18 | 37.07 | 38.25 | 39.03 | 40.01 |
GW650 | 9.12 | 65.66 | 68.94 | 82.57 | 75.22 | 79.14 |
** 5CrNiMo is similar to DIN 1.2711/1.2713, GOST 5XHM steel
** 3Cr2W8V is similar to DIN 1.2581, AISI H21, GOST 3Х2В8Ф steel
** 4Cr5W2VSi is similar to GOST 4Х5В2ФС steel
Thermal fatigue performance:
Figure 4 - Thermal fatigue cracks of GW650 steel
Cycle times | Thermal fatigue crack length /mm | ||||
Distance from surface /mm | |||||
0.45 | 0.90 | 1.35 | 1.70 | 2.35 | |
500 | 0.855 | 0.762 | 0.427 | 0.421 | - |
1000 | 1.827 | 1.901 | 1.292 | 1.170 | 0.605 |
1500 | - | 2.870 | 1.775 | 1.170 | 1.122 |
2000 | - | - | 2.156 | 1.120 | 1.340 |
** Test environment: 650°C ⇋250°C, water cooled
Figure 5 - Thermal fatigue performance comparison
Grade | Thermal fatigue crack length /mm | |
longitudinal | crosswise | |
5CrNiMo | 3.39 | 1.20 |
4Cr5W2VSi | 0.45 | 0.42 |
GW650 | 0.31 | 0.26 |
Depth and surface hardness of ion nitriding layer:
Figure 6 - Depth and surface hardness of ion nitriding layer of GW650 steel
Nitriding temperature /°C |
Holding time /h |
Depth /mm |
Surface hardness /HV0.5 |
460 | 10 | 0.12 | 114~1320 |
530 | 10 | ~0.16 | 1120 |
580 | 10 | 0.28 | 1095 |
640 | 10 | 0.35~0.38 | 810~824 |
Coefficient of thermal conductivity : λ W/(m·K)
Temperature °C | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 |
λ(annealed) | 35.17 | 35.58 | 35.58 | 36.0 | 36.0 | 36.0 | 35.17 | 33.50 | 31.40 |
λ(Q+T) | 30.15 | 31.0 | 31.82 | 32.24 | 32.66 | 32.66 | 32.66 | 32.66 | 31.40 |
Coefficient of linear expansion : α(mm/(mm·°C))
Temperature °C | 20~100 | 20~200 | 20~300 | 20~400 | 20~500 | 20~600 | 20~700 |
Αx 10-6 | 10.07 | 10.81 | 11.58 | 11.94 | 12.28 | 12.64 | 12.91 |
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