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S7 Cold Work Tool Steel

S7 is a general purpose air hardening tool steel having high impact and shock resistance. It has good resistance to softening at moderately high temperatures. This combination of properties makes it suitable for many hot-work and cold-work applications.

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Properties：

● S7 steel is an impact resistant tool steel that can be air-cooled hardened or oil-cooled quenched. Strong impact toughness, wear resistance; Easy to cut, good polishing performance.

Applications：

● It can be used to make cold working tools that need to resist impact force and impact load, such as shear blades, forging dies, chisels and punching machines. It can also be used to operate hot tools whose temperature is not higher than 538℃.

Parameters

Grade		Chemical Composition (%)
Grade		C	Si	Mn	Cr	Mo	V	P	S
GB	5Cr3Mn1SiMo1V1	0.45~0.55	0.20~1.00	0.20~0.90	3.00~3.50	1.30~1.80	≦0.35	≦0.03	≦0.03
ASTM	S7	0.45~0.55	0.20~1.00	0.20~0.90	3.00~3.50	1.30~1.80	≦0.35	≦0.03	≦0.03
DIN	1.2357	0.45~0.55	0.20~0.50	0.20~0.80	3.00~3.60	1.30~1.60	0.05~0.25	≦0.03	≦0.03
Specification		Round BarØ (mm)						Flat Bar (mm)
		Hot Rolled		Hot Forged					EAF	ESR
		Ø12~Ø50		EAF		ESR		Thickness	20~200	20~450
		Ø12~Ø50		Ø50~Ø250		Ø50~Ø650		width	80~610	610max

Physical properties (average values) at ambient temperature
Density [g/cm³]: 7.86

Soft Annealing

Heat to 810-850^oC, 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 at 649/677^oC a minimum of one hour at temperature and cool slowly, then finish machine.

Hardening

Harden from a temperature of 930-960^oC followed by air or oil quenching. Hardness after quenching is 59-61 HRC.

Tempering

Tempering temperature: 150-400^oC.

Tempering Temperature (^oC) vs. Hardness (HRC)