Steel 70HGFA

Designation

Name	The value
Name	The value
Designation GOST Cyrillic	70ХГФА
Designation GOST Latin	70XGFA
Transliteration	70HGFA
By chemical elements	70CrMnV

Description

70HGFA steel is used: for the production of wire rod and heat-treated wire diameter 1.2−5.5 mm, intended for the manufacture of springs; valve springs car engine.

Note

Chrome vanadium spring steel

Standards

Name	Code	Standards
Name	Code	Standards
Steel wire medium and high carbon	В72	GOST 1071-81, TU 14-4-1380-91
Bars and shapes	В32	TU 14-1-4104-86
Blanks. Of the workpiece. Slabs	В31	TU 14-134-326-93

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	Al	V
Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	Al	V
TU 14-134-326-93	0.65-0.72	≤0.015	≤0.015	0.5-0.8	0.3-0.5	0.15-0.3	≤0.15	Rest	≤0.1	-	0.1-0.2
GOST 1071-81	0.65-0.72	≤0.025	≤0.025	0.5-0.8	0.3-0.5	0.15-0.3	≤0.2	Rest	≤0.15	≤0.05	0.1-0.2

Fe is the basis.
According to GOST 1071-81 the chemical composition is given for steel grade 70HGFA.
According to TU 14-1-4104-86, TU 14-134-326-93 the chemical composition is given for steel grade 70HGFA-III. Deviations from the standards of chemical composition in finished rolled products are in accordance with GOST 14959, except copper. The deviation in content of copper in steel is no more than +0,020%.

Mechanical properties

Section, mm	σ_U, MPa
Section, mm	σ_U, MPa
Rod in the supply position on the other 14-1-4104-86
-	≤1270
The wire spring heat-treated in the delivery condition according to GOST 1071-81
1.2-5.5	2060-1270

Description mechanical marks

Name	Description
Name	Description
σ_U	Limit short-term strength

Technological properties

Name	The value
Name	The value
Macrostructure and pollution	The macrostructure of the wire rod according to TU 14-1-4104-86 should not have traces of shrinkage, axial looseness, cracks, inclusions and placenow, bundles. Pollution steel non-metallic inclusions on the average score must not exceed the sulphides and the silicates 1 point each, oxides 1.5 points. The maximum score of non-metallic inclusions of all types should not exceed 2 points.
Microstructure	The microstructure of wire rod, on the other 14-1-4104-86 should consist of perlite 1-3 points on a scale of 1 to GOST 8233. In the surface layer of the wire rod is not allowed the presence of the structure of sorbitol vacation. Martensitic and toostonedtocare areas are not allowed. The average depth bezoperatsionnogo layer (ferrite + transition zone) of the rod surface must not exceed 2% at maximum depth of not more than 2.5% of the diameter.