50HFA

Responsible and heavy duty springs and springs. Not applicable for welded structures.

Substitute: 60S2A, 50HGFA, 9HS

Heavy duty critical parts, which are requirements of a high fatigue strength springs, operating at temperatures up to 300 ° C, and other details.

Country	Section	Category
CIS, Russia, Ukraine	Structural steel	Spring-spring structural steel

Standard	Fe, %	Si, %	Mn, %	Cr, %	Cu, %	Ni, %	V, %	P, %	C, %	S, %
GOST 14959-79	> 96.49	0.17–0.37	0.5–0.8	0.8–1.1	< 0.2	< 0.25	0.1–0.2	< 0.025	0.46–0.54	< 0.025

Temperature, °C	$$E\cdot 10^{9}$$, $$MPa$$	$$\alpha\cdot 10^{6}$$, $$K^{-1}$$	$$\varkappa$$, $$\frac{W}{m\cdot K}$$	$$\rho$$, $$\frac{kg}{m^3}$$	$$c\cdot 10^{-3}$$, $$\frac{J}{kg\cdot K}$$	$$R\cdot 10^{-6}$$, $$\Omega\cdot m$$
20	2.18		40	7800		320
100	2.15	11.7	39	7780	0.49
200	2.1	12.2	38	7750	0.505
300	2	12.9	37	7720	0.51
400	1.88	13.5	36	7680	0.53
500	1.78	14	33	7650	0.56
600	1.6	14.4	31	7610	0.58
700	1.42	14.6	29		0.62
800	1.32	13.1	28		0.7

Rolling	Standard	Size, mm	Classifiers	$$\sigma _{U}$$, $$MPa$$	$$\sigma_{P}$$, $$MPa$$	$$\psi$$, %	d5, %	Treatment
Rod	TU 14-1-950-74		Hardening, average vacation	1300	1100	45	10	Hardening and tempering
Hire	GOST 14959-79		Hardening, average vacation	1270	1080	35	8	Hardening and tempering
The tape is annealed.	GOST 2283-79	0.1–4		880			8
The tape is hardcore.	GOST 2283-79	0.1–4		780–1180

Rolling	Standard	Classifiers	Value, HBW
Hire	GOST 14959-79	raw	302
Hire	GOST 14959-79	heat-treated	269

Weldability	Flake Susceptibility	Propensity to temper brittleness
Not applicable for welded structures	not sensitive	loathsome

Ac₁, K	Ac₃(Ac_m), K	Ar₃(Arc_m), K	Ar₁, K	Mn, K
752	788	746	688	300

USA	Germany	CIS, Russia, Ukraine	European Union
H61500	1.8159 (50CrV4)	60HFA	50СrV4

Standard	Description
GOST 14959-79
GOST 2283-79	GOST 2283-79

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)
$$R\cdot 10^{-6}$$	$$\Omega\cdot m$$	Electrical resistivity

Parameter	Units of measurement	Description
d5	%	Elongation at break
$$\sigma _{U}$$	$$MPa$$	Ultimate tensile strength
$$\sigma_{P}$$	$$MPa$$	Proportionality limit
$$\psi$$	%	Reduction in cross section on fracture

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