Steel R9M4K8

Designation

Name	The value
Designation GOST Cyrillic	Р9М4К8
Designation GOST Latin	P9M4K8
Transliteration	R9M4K8
By chemical elements	-

Description

R9M4K8 steel is used: for the manufacture of tools used in the processing of high-strength stainless and heat resisting steels, alloys and superior alloy steels in terms of increased heating of the cutting edge (cutting tool, milling cutters, shaped cutters, core drills, taps).

Note

Steel has a high tendency to decarburization.

Standards

Name	Code	Standards
Bars and shapes	В22	GOST 1133-71, GOST 2590-2006, GOST 2591-2006
Sheets and strips	В33	GOST 4405-75
Bars and shapes	В32	GOST 7417-75, GOST 14955-77, GOST 19265-73, TU 14-11-245-88

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	V	Mo	W	Co
GOST 19265-73	1-1.1	≤0.03	≤0.03	0.2-0.5	3-3.6	0.2-0.5	≤0.6	Rest	≤0.25	2.3-2.7	3.8-4.3	8.5-9.5	7.5-8.5

Fe is the basis.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	y, %
Rolled steel. Delivery condition
	≥540	≥960	≥7	≥10

Description mechanical marks

Name	Description
s_T\|s_0,2	Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%
σ_U	Limit short-term strength
d₅	Elongation after rupture
y	The relative narrowing

Physical characteristics

Temperature	Е, HPa	G, HPa	r, kg/m³	l, W/(m · °C)
0	229	87	8300	-
20	229	-	8300	-
100	-	-	-	25
200	-	-	-	27
300	-	-	-	28
400	-	-	-	29
500	-	-	-	30
600	-	-	-	31
700	-	-	-	32
900	-	-	-	32

A description of the physical symbols

Name	Description
Е	The normal elasticity modulus
r	Density
l	Coefficient of thermal conductivity
R	UD. the resistivity

Technological properties

Name	The value
The temperature of forging	Start - 1180 °C, the end - 880 °C. Cooling in the wells at 750-800 C.
Sanding behaviour	Reduced
Viscosity	reduced
Wear resistance	increased