1.3243 Steel

Designation by Standards

Steel No.	DIN	EN	AISI	JIS	ГОСТ
1.3243	S6-5-2-5 †	HS6-5-2-5	M35	SKH55	R6M5K5

Chemical Composition (in weight %)

C	Si	Mn	Cr	Mo	Ni	V	W	Others
0.92	max. 0.45	max. 0.40	4.10	5.00	1.90	6.40	-	Co: 4.80

Description
M35 is molybdenum high speed steel. Very high resistance to wear and to softening at elevated temperatures. High resistance of cutting edge and good toughness. Deep hardening response. High hot hardness.

Applications
Highly stressed drills, milling cutters, profile cutting tools, thread cutting drills and cold forming tools.

Physical properties (avarage values) at ambient temperature
Modulus of elasticity [10³ x N/mm²]: 217
Density [g/cm³]: 8.1
Thermal conductivity [W/m.K]: 19.0
Electric resistivity [Ohm mm²/m]: 0.60
Specific heat capacity[J/g.K]: 0.46

Coefficient of Linear Thermal Expansion 10^-6 ^oC^-1

20-100^oC	20-200^oC	20-300^oC	20-400^oC	20-500^oC	20-600^oC	20-700^oC
9.7	10.5	11.0	11.4	11.5	12.0	12.5

Soft Annealing
Heat to 820-880^oC, cool slowly in furnace. This will produce a maximum Brinell hardness of 230-300.

Stress Relieving
Stress relieving to remove machining stresses should be carried out by heating to 650^oC, holding for one hour at heat, followed by air cooling. This operation is performed to reduce distortion during heat treatment.

Hardening
Heat to 450-600^oC, preheat to 850^oC and then to 1050^oC. Harden from a temperature of 1210-1250^oC followed by oil, air quenching or warm bath 550^oC. Hardness after quenching is 64-66 HRC.

Transformation temperatures: Ac₁=824^oC , Ac₃=853^oC.

Tempering
Tempering temperature: 3 x 1 hour at 540-570^oC.

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

200^oC	300^oC	400^oC	500^oC	525^oC	550^oC	575^oC	600^oC	650^oC	700^oC
63	61	62	64	64.5	65	64	63	55	46

Forging
Hot forming temperature: 1100-900^oC.

Machinability
No data.

Corrosion Resistance
Not normally employed in applications requiring corrosion resistance.

Remark
All technical information is for reference only.