Introduction
S7 is a general purpose air hardening tool steel having high impact and sock resistance. it has good resistance to softening at moderately high temperatures. making S7 steel suitable for many hot-work and cold-work applications.
Applications : Chisels, rivet sets, punches, driver bolts. Hot punching and shearing.
Physical properties (average values) at ambient temperature : Average values of physical properties at ambient temperature for S7 steel are as follows: Density [gcm ³] : 7.86
Chemical Composition : (%)
| C | Si | Mn | Cr |
| 0.45-0.60 | 0.45-0.55 | 0.65-0.80 | 3.20-3.40 |
| Mo | Ni | V | W |
| 1.50 | -- | 0.20-0.35 | -- |
Grades Equivalent :
| STANDARD | RAVNE | DIN | EN | AISI/SAE |
| 1.2357 | OH253 | 50CrMoV13-1 | -- | S7 |
Coefficient of Linear Thermal Expansion 10¯6 °C¯¹
| 20-100°C | 20-200°C | 20-300°C | 20-400°C |
| 11.7 | 12.9 | 13.3 | 13.8 |
| 20-500°C | 20-600°C | 20-700°C |
| 14.1 | 14.3 | 14.6 |
Soft Annealing : Heat 810-850 °C, cool slowly in furnace. This will produce a maximum brinell hardness of 229.
Stress Relieving : To Relieve machining stresses for greater accuracy in hardening - first rough machine, then anneal below the critical 649/677 °C a minimum of one hour at temperature and cool slowly, then finish machine.
Hardening : Harden from a temperature 930-960 °C followed by air or oil quenching. Hardness after quenching is 59-61 HRC.
Tempering : Tempering temperature: 150-400 °C
Tempering Temperature(°C) vs. Hardness (HRC)
| 100°C | 200°C | 300°C | 400°C |
| 59 | 57 | 54 | 53 |
| 500°C | 550°C | 600°C | 650°C |
| 52 | 52 | 48 | 41 |
Forging Hot forming temperature : The hot forming temperature for S7 steel is between 1060-1121 °C
Machinability : The machinability of S7 alloy may be rated at about 75/80 % of a 1% carbon tool steel.
Corrosion Resistance : Corrosion resistance of S7 steel is better than that of plain carbon steels. However it will rust unless given protective treatment.
Forms manufactured : Please refer to the Dimensional Sales Program for the various forms of S7 steel manufactured.
