18ХН3МА steel is used: for the production of hot rolled bars used for the manufacture of paws and cutter drill bits all sizes with air purge, as well as bits from 151 mm and less, borgonovo by hot forming; drill bits with a diameter of 320 mm or more.

Note

Temperature range of use of steel from -70 °C to +450 °C.

Standards

Name	Code	Standards
Bars and shapes	В32	TU 3-26-79, TU 3-27-79, TU 3-850-80, TU 3-938-79

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	Mo
TU 3-26-79	0.15-0.2	≤0.02	≤0.02	0.3-0.6	0.4-0.7	0.17-0.37	2.85-3.25	Rest	≤0.2	0.25-0.35
TU 3-850-80	0.15-0.2	≤0.015	≤0.02	0.35-0.65	0.4-0.7	0.17-0.37	2.75-3.15	Rest	≤0.3	0.2-0.3

Fe is the basis.
According to TU 3-26-79 the chemical composition is given for steel grade 18HN3MA-VD.
According to TU 3-850-80 the chemical composition is given for steel grade 18HN3MA. The presence of residual titanium in the steel to 0.030%, tungsten to 0.20% and vanadium to 0.050% is not a defect.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	y, %	KCU, kJ/m²
Bars hot rolled as supplied on the other 3-850-80. 1-I'm quenching in oil from 890±15 °C + 2 quenching in oil from 775±15 °C + Vacation at 170-220 °C, air cooling (longitudinal samples)
	≥882	≥980	≥11	≥45	≥980

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

Physical characteristics

Temperature	r, kg/m³	l, W/(m · °C)	a, 10^-6 1/°C
1506	6990	-	82
20	-	25	-

A description of the physical symbols

Name	Description
Е	The normal elasticity modulus
r	Density
l	Coefficient of thermal conductivity
R	UD. the resistivity

Technological properties

Name	The value
Macrostructure and pollution	Macrostructure of steel ready rods on the other 3-850-80 checked for breaks and pickled Templeton, must meet the requirements of GOST 4543 and should not have shrinkage, porosity, bubbles, cracks, delamination, inclusions and placenow. Upon detection placenow steel is rejected. Evaluation of the macrostructure of the etched on Templeton is on scales GOST 10243. Permitted: Central porosity; a point inhomogeneity; phase separation squared, General, regional and Pousada liquation not more than 2 points; layer-by-layer crystallization and the light circuit is not more than 3 points. Not allowed subcortical bubbles and intergranular cracks. Steel is controlled on the contamination of non-metallic inclusions, the content of which is determined according to GOST 1778 for 6 samples and should not exceed the contents in points (average/maximum): - FROM Point - 2,0/4,0; - Stroke OS - 3,0/4,0; - Fragile CX - 3,5/4,0; Plastic SP 2,5/4,0; - non-deformable SN - 2,5/4,0; - Sulfides C - 2,5/4,0; Nitrides N - 1,5/2,5.
Microstructure	The microstructure of the initial sample of steel 18ХН3МА-W is a coarse-grained pearlitic-ferritic structure with dispersed inclusions of the alloying elements. After the gas carburizing and hardening with following tempering forms a fine-grained martensitic structure. After electrolytic-plasma treatment the microstructure of steel 18ХН3МА-sh has a fine-grained martensitic-bantou structure. Under cyclic heating a highly concentrated plasma energy, the transformation of pearlite into austenite. The austenitic grain size shall be not larger than the number 5 according to GOST 5639.
Particularities of production of goods	Bars hot rolled on the other 3-850-80 are supplied in heat-treated (annealed or vysokoopasnye) with hardness not exceeding 269 HB (indentation diameter not less than 3.7 mm). Hardenability of steel (after normalization at 920±10 °C or quenching from 890±10 °C) - Hardness HRC should be at a distance of 4.5 mm from the end of 37.5÷43,5, and at a distance of 30 mm from the end - 25÷35.

Steel 18ХН3МА

Designation

Description