Characteristic:It is one of the typical sperhard Co hss ,with high hardness and hot hardness,high red hardness and good grindability.

Similar steel grade

 

标准	GB	JIS	ASTM	DIN	Bohler	ERASTEEL
钢号	W2Mo9Cr4VCo8	SKH59	M42	S2-10-1-8 1.3247	S500	EM42

 Chemical Composition:(％)

C	W	Mo	Cr	V	Co	Mn	Si	P	S
1.05-1.05	1.15-1.85	9.00-10.00	3.50-4.25	0.95-1.35	7.75-8.75	0.15-0.40	0.15-0.65	≤0.03	≤0.02

 UNEDR ANNEALED CONDITION

Hardness:HB205-255

Delivery status:

As Cold drawn /Hot rolled /forged,in annealed condition.

Size:

Cold drawn bar:￠2.2-14.2mm

Hot rolled bar:￠8.0-80.0mm

Forged bar:￠81.0-250.0mm

Coil:￠6.5-16.0m

Heat Treatment: 

Annealing:

Annealing temperature:860-880℃,keep this temperature by 2-4 hours,then cooling to 600℃ in the speed of 20-30℃/h if after cold drawn precess,suggest add stress relieving annealing process Under the temperature of 600-700℃,keep this temperature by 2 houres.

Quenching & Tempering(salt bath)

Quenching:

Pre-heating in two steps:

Heating temperature under :400-500℃ and 850-900℃

Austenitizing temperature :1170-1190℃

Heating coefficient 10-15sec/mm ,quenching under 580-620℃,then cooling to room temperature.

Tempering:

Tempering temperature under :530-560℃,temperature 3 times, each time 1hour ,then cooling to room temperature.

Note:1.Cutting tools in simple shape which requires high hardness,suggest adopt 1190-1200℃ as quenching temperature,530-540℃ as tempering temperture resulted in HRC 67-69.

         2 .Cutting Tools in complex shape (such as milling cutter,tap)suggest adopt 1170-1190℃ as quenching temperature.550-560℃ as tempering temperature,resulted in HRC 66.5-67.5.(with Good toughness)

         3 .Straightening under 200-450℃ after Quenching.