12KH2NVFA steel is used: for the manufacture of welded assemblies and structures, not subjected to heat treatment after welding (including off), which require increased strength; loaded welded parts; solid-rolled rings for different purposes; the spars of the car.

Note

Alloy structural steel high quality with low carbon content.
Steel can be used for carburized parts operating at temperatures of 230−250 °C; and nesvorny welded parts operating at temperatures up to +500 °C.

Standards

Name	Code	Standards
Sheets and strips	В33	GOST 11268-76, GOST 11269-76
Steel pipes and fittings to them	В62	GOST 21729-76, TU 14-3-967-80, TU 14-3-463-2005, TU 14-3-975-80
Sheets and strips	В23	GOST 82-70
Classification, nomenclature and General rules	В20	OST 1 90005-91
Blanks. Of the workpiece. Slabs	В31	OST 1 90280-79, TU 1-92-156-90, TU 14-1-1278-75
Bars and shapes	В32	OST 1 92049-76, TU 14-1-1885-85, TU 14-1-2854-79, TU 14-1-950-74, TU 14-1-3238-81, TU 14-1-3238-2006, TU 14-1-1271-75
Bars and shapes	В22	TU 14-2-490-82

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	V	W
TU 14-1-1885-85	0.09-0.16	≤0.015	≤0.025	0.3-0.7	1.9-2.4	0.17-0.37	0.8-1.2	Rest	≤0.25	0.18-0.28	1-1.4

Fe is the basis.
According to TU 14-1-3238-81 the chemical composition is given for steel grade 12Х2НВФА. For steel grade 12Х2НВФА-СШ the content S≤0,015%.
According to TU 14-1-1885-85 the chemical composition is given for steel grade 12Х2НВФА-ВД (ЭИ712-ВД). The presence of molybdenum up to 0.15%, titanium up to 0.030% is not a defective feature. Partial replacement of tungsten with residual molybdenum is allowed in the steel at the rate: one part by weight of molybdenum replaces three parts by weight of tungsten, while the content of tungsten in steel should be at least 0.60%. The allowable variation in manganese content in steel is ± 0.010%.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	y, %	KCU, kJ/m²	HB, MPa	HRC
Pipe seamless cold drawn, cold rolled and toplocatie, heat-treated in the delivery condition according to GOST 21729-76
	-	≥490	≥16	-	-	-	-
Gradation of performance properties of the finished heat-treated parts for OST 1 90005-91
-	-	980-1180	-	-	-	285-341	30-37
-	-	-	-	-	-	285-415	30-43.5
Ring forged in OST 1 92049-76. Quenching in oil with 895-925 °C + Vacation at 500-550 °C, air cooling
15	≥835	≥930	≥9	≥44	≥588	285-376	-
Steel hot-rolled sheet (4-60 mm) 4-th and 5-th categories. Quenching in oil with 910±15 °C + Vacation at 490-550 °C, air cooling
	-	≥1030	≥10	-	≥590	-	-
Bars and strip hot rolled and forged. Quenching in oil with 895-925 °C + Vacation at 500-550 °C, air cooling
	≥885	≥980	≥12	≥55	≥785	285-376	-
Rods made of steel 12KH2NVFA (ЭИ712) TU 14-1-1885-85. Quenching in oil with 895-925 °C + Vacation at 480-510 °C, air cooling. In the graph KCU KCU values are shown along the fiber/KCU across the grain
Образец 15х15	≥885	≥980	≥12	≥55	≥784/-	285-374	-

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
KCU	Toughness
HB	Brinell hardness number
HRC	Rockwell hardness (indenter diamond spheroconical)

Technological properties

Name	The value
Weldability	Well weldable manual arc, contact and agrono-arc (manual and automatic) welding; satisfactory — and atomic-hydrogen gas welding.
Macrostructure and pollution	Macrostructure of steel when testing for the breaks in the longitudinal direction and transverse templeto selected from rolled, should not have shrinkage, porosity, bubbles, cracks, delamination, inclusions and placenow and defects of fracture, listed in Annex 3 GOST 10243. The Central porosity, point heterogeneity and phase separation in the square should not exceed 1 points; layer-by-layer crystallization and the bright loop - 3 points reference scales GOST 10243. All other defects under GOST 10243, are not allowed. Pollution steel non-metallic inclusions should be according to the average score is not higher (in points): oxides of point 1,5, 2,0 stroke oxides, silicates fragile 1,0, 1,0 silicates plastic, silicates, non-deformed 2,5, 2,5 sulfides, nitrides stroke and point 1,0.
Features of heat treatment	Steel 12KH2NVFA strengthen by heat treatment (quenching in oil with subsequent tempering or normalizing with tempering).

Steel 12KH2NVFA (ЭИ712)

Designation

Description