By visiting this site, you accept the use of cookies. More about our cookie policy.

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