40HFA (40HF)

The improved state-spline shafts, rods, set screws, crosshead, excavating shafts and other parts operating at temperatures up to 400 ° C; after quenching and low tempering — worm shafts and other components increased durability.

Classification

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

Chemical composition

Standard	Fe, %	Si, %	Mn, %	Cr, %	Cu, %	Ni, %	V, %	P, %	C, %	S, %
GOST 4543-71	96.46–98.06	0.17–0.37	0.5–0.8	0.8–1.1	< 0.3	< 0.3	0.1–0.18	< 0.025	0.37–0.44	< 0.025

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Physical characteristics

Temperature, °C	$$E\cdot 10^{9}$$, $$MPa$$	$$\alpha\cdot 10^{6}$$, $$K^{-1}$$	$$\varkappa$$, $$\frac{W}{m\cdot K}$$	$$\rho$$, $$\frac{kg}{m^3}$$	$$c\cdot 10^{-3}$$, $$\frac{J}{kg\cdot K}$$
20	215		37	7810
100	212	12.1	37		0.466
200	205	12.6	37		0.508
300	199	13	36		0.529
400	182	13.3	33		0.563
500	173	13.8	31		0.592
600	166	14.2	31		0.621
700	144	14.6	30		0.634
800	135	11.8	28		0.664

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
Rod	GOST 4543-71	25			880	735	10	50	880	Hardening and tempering
Forgings		100–300			615	395	15	40	540	Hardening and tempering
Forgings		300–500			615	395	13	35	490	Hardening and tempering

Brinell hardness number

Rolling	Standard	Classifiers	Value, HBW
Alloy	GOST 4543-71	annealing	241

Technological Properties

Weldability	Flake Susceptibility	Propensity to temper brittleness
Difficult to weld	sensitive	inclined

Critical point temperatures

Ac₁, K	Ac₃(Ac_m), K	Ar₃(Arc_m), K	Ar₁, K	Mn, K
760	800	725	680	218

Analogues

USA	Germany
G41400	1.7223 (41CrMo4)

Standards

Standard	Description
GOST 4543-71

Description of chemical elements

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

Description of physical characteristics

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)
$$\rho$$	$$\frac{kg}{m^3}$$	The density of the material
$$c\cdot 10^{-3}$$	$$\frac{J}{kg\cdot K}$$	The specific heat of the material (range 20°C–T)

Description of mechanical properties

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

Designation of types of weldability

Parameter	Units of measurement	Description
no limits		Welding is performed without heating and without subsequent heat treatment
Boundedly welded		Welding is possible with heating up to 100–120 °C and subsequent heat treatment
Difficult to weld		For obtaining quality welded joints, additional operations are required: heating up to 200–300 °C for welding, heat treatment after welding — annealing
Not applicable for welded structures

Description of temperatures of critical points

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