03KH21N21M4GB steel is used: for the manufacture of welded structures and components operating in conditions of hot phosphoric acid with a mixture of fluorine and sulfur compounds, and sulfuric acid of low concentration at temperatures up to +80 °C, nitric acid at temperatures up to +95 °C; parts of equipment for chemical industry (production of phosphoric acid, fertilizers, cellulose acetate, vinyl acetate, etc.); equipment, working in conditions of intensive wear (mixers, separators, extractors); welding electrodes used in the manufacture of equipment for energy and chemical engineering.

Note

Steel is a complex alloy corrosion-resistant austenitic class.

Standards

Name	Code	Standards
Processing of metals by pressure. Forgings	В03	GOST 25054-81
Sheets and strips	В33	GOST 5582-75, GOST 7350-77, TU 14-1-4364-87
Classification, nomenclature and General rules	В30	GOST 5632-72
Blanks. Of the workpiece. Slabs	В31	OST 3-1686-90, TU 14-1-2134-77
Thermal and thermochemical treatment of metals	В04	STP 26.260.484-2004
Bars and shapes	В32	TU 14-1-1190-75, TU 14-11-245-88, TU 14-1-4319-87
Steel pipes and fittings to them	В62	TU 14-3-694-78, TU 14-3-696-78, TU 14-3-751-78

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	V	Ti	Mo	W
GOST 5632-72	0.03	≤0.02	≤0.03	1.8-2.5	20-22	≤0.6	20-22	Rest	≤0.3	≤0.2	≤0.2	3.4-3.7	≤0.2

Fe is the basis.
According to GOST 5632-72 the content of Nb% = 15C% is 0.8%.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	d₁₀	y, %
Hot rolled sheet (of 1.5-3.9 mm) and cold rolled (0,7-3,9 mm) steel according to GOST 5582-75. Quenching in water or air with 1080-1130 °C
-	≥245	≥540	-	≥25	-
Hot rolled sheet (4,0-25,0 mm) and cold rolled (4,0-5,0 mm) steel according to GOST 7350-77. Quenching in water or under a water shower with 1060-1120 °C
-	≥295	≥590	≥30	-	-
Bars hot rolled and forged at STP 26.260.484-2004. Quenching in water or under a water shower with 1060-1120 °C
	≥300	≥600	≥30	-	≥30

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
d₁₀	Elongation after rupture
y	The relative narrowing

Technological properties

Name	The value
Weldability	Without ogranicheniy
Features of heat treatment	Steel products 03KH21N21M4GB should be hardened with 1060-1120 °C, holding time wall thickness up to 15mm - 30 min, more than 15 mm - 30 min + 1 min per 1 mm of maximum wall thickness; the product is cooled in water or air.

Steel 03KH21N21M4GB (ЗИ35)

Designation

Description