38HMA

important parts of general purpose machinery.

Classification

Country	Section	Category
Country	Section	Category
CIS, Russia, Ukraine	Structural steel	Alloyed structural steel

Chemical composition

Standard	Fe, %	Si, %	Mn, %	Cr, %	Cu, %	Ni, %	P, %	C, %	S, %	Mo, %
Standard	Fe, %	Si, %	Mn, %	Cr, %	Cu, %	Ni, %	P, %	C, %	S, %	Mo, %
GOST 4543-71	96.31–98.03	0.17–0.37	0.35–0.65	0.9–1.3	< 0.3	< 0.3	< 0.025	0.35–0.42	< 0.025	0.2–0.3

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Physical characteristics

Temperature, °C	$E\cdot 10^{9}$ , $MPa$	$\alpha\cdot 10^{6}$ , $K^{-1}$	$\varkappa$ , $\frac{W}{m\cdot K}$	$c\cdot 10^{-3}$ , $\frac{J}{kg\cdot K}$	$R\cdot 10^{-6}$ , $\Omega\cdot m$
Temperature, °C	$E\cdot 10^{9}$ , $MPa$	$\alpha\cdot 10^{6}$ , $K^{-1}$	$\varkappa$ , $\frac{W}{m\cdot K}$	$c\cdot 10^{-3}$ , $\frac{J}{kg\cdot K}$	$R\cdot 10^{-6}$ , $\Omega\cdot m$
20	211		33		0.257
100	201	12.4	35	0.496	0.28
200	194	13.1	38	0.508	0.31
300	184	13.7	39	0.525	0.38
400	174	14.2	36	0.538	0.47
500	169	14.5	34	0.567	0.58
600	166	14.6	33	0.6	0.72
700	141	14.7	31	0.672	0.87
800	129	11.2	27	0.697	1.06

Mechanical properties at 20 °C

Rolling	Standard	Size, mm	Tension	Classifiers	$\sigma _{U}$ , $MPa$	$\sigma_{P}$ , $MPa$	$\epsilon_L$ , %	$\psi$ , %	$KCU\cdot 10^{3}$ , $\frac{J}{m^2}$	Treatment
Rolling	Standard	Size, mm	Tension	Classifiers	$\sigma _{U}$ , $MPa$	$\sigma_{P}$ , $MPa$	$\epsilon_L$ , %	$\psi$ , %	$KCU\cdot 10^{3}$ , $\frac{J}{m^2}$	Treatment
Rod		25			980	885	11	45	690	Tempering 850 ° C, oil, leave 600 ° C, air

Critical point temperatures

Ac₁, K	Ac₃(Ac_m), K	Ar₃(Arc_m), K	Ar₁, K
Ac₁, K	Ac₃(Ac_m), K	Ar₃(Arc_m), K	Ar₁, K
758	805	725	650

Analogues

USA	Germany
USA	Germany
4142	1.7223 (41CrMo4)

Standards

Standard	Description
Standard	Description
GOST 4543-71

Description of chemical elements

Element	Units of measurement	Description
Element	Units of measurement	Description
Fe	%	Iron
Si	%	Silicon
Mn	%	Manganese
Cr	%	Chrome
Cu	%	Copper
Ni	%	Nickel
P	%	Phosphorus
C	%	Carbon
S	%	Sulfur
Mo	%	Molybdenum

Description of physical characteristics

Parameter	Units of measurement	Description
Parameter	Units of measurement	Description
$E\cdot 10^{9}$	$MPa$	Elastic modulus
$\alpha\cdot 10^{6}$	$K^{-1}$	Coefficient of thermal (linear) expansion (range 20°C–T)
$\varkappa$	$\frac{W}{m\cdot K}$	Coefficient of thermal conductivity (the heat capacity of the material)
$c\cdot 10^{-3}$	$\frac{J}{kg\cdot K}$	The specific heat of the material (range 20°C–T)
$R\cdot 10^{-6}$	$\Omega\cdot m$	Electrical resistivity

Description of mechanical properties

Parameter	Units of measurement	Description
Parameter	Units of measurement	Description
$\sigma _{U}$	$MPa$	Ultimate tensile strength
$\sigma_{P}$	$MPa$	Proportionality limit
$\epsilon_L$	%	Elongation at break (longitudinal)
$\psi$	%	Reduction in cross section on fracture
$KCU\cdot 10^{3}$	$\frac{J}{m^2}$	Impact toughness

Description of temperatures of critical points

Parameter	Units of measurement	Description
Parameter	Units of measurement	Description
Ac₁	K
Ac₃(Ac_m)	K
Ar₃(Arc_m)	K
Ar₁	K