7X3 steel
7X3 steel
Steel 7X3: Handbook of steels and alloys. Below is systematized information on the purpose, chemical composition, types of supply, substitutes, critical point temperatures, physical, mechanical, technological and foundry properties for the grade — Steel 7X3.
General information on 7X3 steel
| Substitute for the brand |
| steel 8Х3. |
| Type of delivery |
| Sections, including shaped: GOST 5950−73, GOST 2590−71, GOST 2591−71. Calibrated bar GOST 5950−73, GOST 7417−75, GOST 8559−75, GOST 8560−78. Grinded rod and silversilver GOST 5950−73, GOST 14955−77. Strip GOST 5950−73, GOST 4405−75. Forged and forged blanks GOST 5950−74, GOST 1133−71, GOST 7831−78. |
| Application |
| The tool (punches, dies) for hot upsetting of fasteners and blanks of carbon and low-alloy constructional steels on horizontal forging machines, stamping parts (dies. punches, ejectors) for hot pressing and extrusion of these materials on crank presses, bending, trimming and punching dies. |
Chemical composition of steel 7X3
| Chemical element |
% |
| Vanadium (V), not more |
0.15 |
| Tungsten (W), not more |
0.20 |
| Silicon (Si) |
0.15−0.35 |
| Manganese (Mn) |
0.15−0.40 |
| Copper (Cu), not more |
0.30 |
| Molybdenum (Mo), max. |
0.20 |
| Nickel (Ni), not more than |
0.35 |
| Sulfur (S), not more than |
0.030 |
| Titanium (Ti), not more than |
0.03 |
| Carbon (C) |
0.65−0.75 |
| Phosphorus (P), not more |
0.03 |
| Chrome (Cr) |
3.20−3.80 |
Mechanical properties of steel 7X3
Mechanical properties
| Heat treatment, delivery condition |
σ0.2, MPa |
σB, MPa |
δ5, % |
ψ, % |
KCU, J/m2 |
HRCe |
| Annealing at 650−700°C. Tempering at 850−880°C, oil. Tempering 480−500°C. |
1620−1710 |
1670−1760 |
4−7 |
16−19 |
18−20 |
40−44 |
Mechanical properties depending on tempering temperature
| t tempering temperature, °C |
σ0, 2, MPa |
σB, MPa |
δ5, % |
ψ, % |
KCU, J/m2 |
HRCe |
| Hardening at 870 °C in oil. Tempering temperature 2 h. |
| 300 |
1650 |
1930 |
4 |
12 |
17 |
52 |
| 400 |
1440 |
1690 |
5 |
24 |
29 |
47 |
Mechanical properties as a function of test temperature
| t test temperature,°C |
σ0, 2, MPa |
σB, MPa |
δ5, % |
ψ, % |
KCU, J/m2 |
HRCe |
| Hardening at 870 °C, oil. Tempering at 500 °C, 2h. |
| 20 |
1240 |
1320 |
10 |
36 |
37 |
40 |
| 300 |
880 |
1030 |
12 |
34 |
71 |
|
| 400 |
780 |
910 |
16 |
55 |
67 |
|
| 500 |
550 |
690 |
18 |
68 |
51 |
|
Technological properties of steel 7X3
| Forging temperature |
| Starts at 1180, ends at 800. Sections up to 300 mm are cooled in the pit. |
| Weldability |
| Not applicable for welded structures. |
| Tendency to temperability |
| inclined |
| Flockensitive |
| susceptible |
Steel 7X3 critical point temperature
| Critical point |
°С |
| Ac1 |
770 |
| Ar1 |
730 |
| Mn |
400 |
Steel hardness 7X3
| Delivery condition, heat treatment regime |
HRCe surface |
| Hardening 850−880 С, oil. Tempering 150−200 С. |
61−63 |
| Hardening 850−880°C, oil. Tempering 200−300°C. |
59−61 |
| Tempering at 850−880°C with oil. Tempering at 300−400°C. |
56−59 |
| Tempering at 850−880°C, oil. Tempering 400−500 C. |
52−56 |
| Tempering at 850−880°C, oil. Tempering 500−600 C. |
41−52 |
