O7 Cold Working Tool Steel

 

Introduction:

O7 Cold Working Die Steel is one kinds of oil hardening cold working die steel, which consists of chromium and manganese, and has higher tungsten content than grade O1. The O7 steel has the best wear resistance among the O series steels, however, it has relatively low hardenability.

 

Applications:

Cutting and punching tools for sheet thickness up to 6 mm, also for paper and plastics, roll shear blades for sheet thickness up to 6 mm, small bending and drawing tools, thread cutting tools, reamers, woodworking tools, gauges and other measuring tools, small inserts and plastic moulds.

 

Quality Standard:

ASTM A681 – 08 Standard Specification for Tool Steels Alloy.

BS EN ISO 4957 Tool Steel

JIS G4404 Alloy Tool Steel

 

All Grades Comparison:

ASTM	Material No.	EN	JIS	GB
O7	1.2419	105WCr6	SKS31	CrWMn

 

Chemical Composition(%)

Steel Grade	C	Si	Mn	P	S	Cr	V	W	Mo
O7	1.10-1.30	0.10-0.60	0.20-1.00	0.030 max	0.030 max	0.35-0.85	0.15-0.40	1.00-2.00	0.30 max
SKS31	0.95-1.05	0.35 max	0.90-1.20	0.030 max	0.030 max	0.80-1.20	/	1.00-1.50	/
105WCr6	1.00-1.10	0.1-0.40	0.80-1.10	0.030 max	0.030 max	0.90-1.10	/	1.00-1.30	/
CrWMn	0.90-1.05	0.40 max	0.80-1.10	0.030 max	0.030 max	0.90-1.20	/	1.20-1.60	/

 

HEAT TREATMENT:

 FORGING: Hot forming temperature: 1050-850oC

 SOFT ANNEALING: Heat to 720-750oC, cool slowly in furnace. This will produce a maximum Brinell hardness of 230.

 STRESS RELIEVING:Stress relieving to remove machining stresses should be carried out by heating to approx. 650oC, holding for 1-2 hours at heat, followed by air cooling. This operation is performed to reduce distortion during heat treatment.

 HARDENING:Harden from a temperature of 800-830oC followed by oil quenching or warm bath quenching approx. 200oC. Hardness after quenching is 63-65 HRC.

 TEMPERING: Tempering temperature: See the data bellow.

Tempering Temperature	Hardness(HRC)
100oC	64
200oC	61
300oC	58
400oC	54
500oC	49
600oC	41
650oC	30

 

Mill′s test certificate:

EN 10204/3.1 with all relevant data reg. chem. composition, mech. properties and results of testing.