20KHN3A steel is used: for the production of gears, shafts, bushings, power studs, bolts, nuts, worms, couplings and other case hardening of parts, which are requirements of high strength, ductility and toughness of core and high surface hardness, working under shock loads and at low temperatures; details of pipeline valves; paws and cutter drill bits all sizes with air purge, as well as bits from 151 mm and less, borgonovo by hot forming.

Note

Structural steel high-quality stainless.

Standards

Name	Code	Standards
Sheets and strips	В23	GOST 103-2006
Bars and shapes	В32	GOST 1051-73, GOST 4543-71, GOST 7417-75, GOST 8559-75, GOST 8560-78, GOST 14955-77, TU 14-1-5414-2001, TU 3-850-80, TU 14-1-2118-77, TU 14-1-2765-79, TU 14-1-4612-89, TU 14-1-950-74, TU 14-11-245-88, TU 14-1-5228-93, TU 14-136-367-2008
Bars and shapes	В22	GOST 1133-71, GOST 8319.0-75, GOST 2590-2006, GOST 2591-2006, GOST 2879-2006
Processing of metals by pressure. Forgings	В03	GOST 8479-70, ST ЦКБА 010-2004
Blanks. Of the workpiece. Slabs	В21	OST 14-13-75
Blanks. Of the workpiece. Slabs	В31	OST 3-1686-90, TU 14-1-4944-90, TU 1-92-156-90
Thermal and thermochemical treatment of metals	В04	ST ЦКБА 026-2005

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	V	Ti	Mo	W
TU 14-1-950-74	0.17-0.24	≤0.025	≤0.025	0.3-0.6	0.6-0.9	0.17-0.37	2.75-3.15	Rest	≤0.25	≤0.05	≤0.03	≤0.15	≤0.2
TU 14-1-2765-79	0.17-0.24	≤0.025	≤0.025	0.3-0.6	0.6-0.9	0.17-0.37	2.75-3.15	Rest	≤0.25	≤0.1	≤0.03	≤0.15	≤0.2
GOST 4543-71	0.17-0.24	≤0.025	≤0.025	0.3-0.6	0.6-0.9	0.17-0.37	2.75-3.15	Rest	≤0.3	≤0.05	≤0.03	≤0.15	≤0.2

Fe is the basis.
GOST 4543-71 regulates the content of high-quality steel: P≤0,025%; S≤0.015%; Сu≤0.25%.
According to TU 14-1-2765-79, the chemical composition is given for steel grade 20ХН3А-Ш.
According to TU 14-1-950-86, the chemical composition is given for steel grade 20ХН3А.
TU 14-1-4612-89 chemical composition is given for steel grade 20ХН3А-Ш. Allowable deviations in the chemical composition in the finished rolled product and the mass fraction of residual tungsten, molybdenum, titanium and vanadium - according to GOST 4543.
According to TU 3-850-80 the chemical composition is given for steel grade 20ХН3А. The presence of residual titanium in the steel to 0.030%, tungsten to 0.20%, molybdenum to 0.15% and vanadium to 0.050% is not a defect.

Mechanical properties

Section, mm	t отпуска, °C	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	y, %	KCU, kJ/m²	HB, MPa	HRC
Forgings. Hardening + Vacation
≤100	-	≥590	≥735	≥14	≥45	≥590	235-277	-
≤100	-	≥685	≥835	≥13	≥42	≥590	262-311	-
Blank pieces of pipe fittings. Quenching in oil from 820-840 °C (exposure for 2.5-4.5 hours depending on the thickness and weight of the workpiece) with the following tempering in oil or air
≤50	500-580	675-785	≥835	≥12	≥55	≥800	248-293	-
Rolled steel. Quenching in oil from 850 °C + Vacation at 200 °C, air cooling
≤5	-	≥1220	≥1420	≥12	≥55	≥860	-	44
Rolled steel. Normalization at 860 °C, air cooling + Quenching in oil from 810 °C to + Vacation
-	200	≥1270	≥1510	≥15	≥60	≥730	-	≥43
Blank pieces of pipe fittings. Quenching in oil from 820-840 °C (exposure for 2.5-4.5 hours depending on the thickness and weight of the workpiece) with the following tempering in oil or air
50-80	500-580	≥640	≥785	≥10	≥42	≥800	262-311	-
Rolled steel. Quenching in oil from 850 °C + Vacation at 200 °C, air cooling
16-20	-	≥1080	≥1270	≥13	≥65	≥890	-	44
Rolled steel. Normalization at 860 °C, air cooling + Quenching in oil from 810 °C to + Vacation
-	300	≥1260	≥1370	≥12	≥62	≥540	-	≥42
Bars hot rolled as supplied on the other 14-1-4612-89. 1-I'm quenching in oil with 880-900 °C + 2 quenching in oil from 800-820 °C + Vacation at 170-220 °C, air cooling (longitudinal samples)
25	-	≥885	≥980	≥8	≥40	≥880	≤269	-
Rolled steel. Quenching in oil from 850 °C + Vacation at 200 °C, air cooling
6-15	-	≥1180	≥1370	≥13	≥65	≥760	-	44
Rolled steel. Normalization at 860 °C, air cooling + Quenching in oil from 810 °C to + Vacation
-	400	≥1180	≥1260	≥13	≥64	≥590	-	≥39
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	≥8	≥40	≥784	-	-
Rolled steel. Quenching in oil at 880 °C to + Vacation at 600 °C, air cooling
20-30	-	≥700	≥800	≥20	≥70	-	-	-
Rolled steel. Normalization at 860 °C, air cooling + Quenching in oil from 810 °C to + Vacation
-	500	≥960	≥1000	≥19	≥66	≥830	-	≥32
Bars and strip hot rolled and forged. Quenching in oil or warm water with 820-840 °C + Vacation at 400-500 °C, cooling in water or oil
	-	≥835	≥980	≥10	≥55	≥981	294-341	-
Rolled steel. Quenching in oil at 880 °C to + Vacation at 600 °C, air cooling
30-50	-	≥610	≥730	≥19	≥71	-	-	-
Rolled steel. Normalization at 860 °C, air cooling + Quenching in oil from 810 °C to + Vacation
-	600	≥720	≥780	≥24	≥73	-	-	≥22
Rolled steel. Cementation at 920-950 °C + Normalization at 870-890 °C, air cooling + Vacation at 630-660 °C, cooling in air and Quenching in oil with 790-810 °C + Vacation at 180-200 °C, air cooling
50-100	-	≥690	≥830	≥11	≥50	≥690	≥240	59-63
Rolled steel. Quenching in oil at 880 °C to + Vacation at 600 °C, air cooling
50-80	-	≥580	≥700	≥23	≥68	-	-	-
100-220	-	≥570	≥690	≥23	≥67	-	-	-
100-220	-	≥510	≥660	≥14	≥51	-	-	-

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)

Physical characteristics

Temperature	Е, HPa	G, HPa	r, kg/m³	l, W/(m · °C)	R, Mr. · m	a, 10^-6 1/°C	С, J/(kg · °C)
100	204	80	7830	35	300	115	494
300	188	70	7760	33	450	12	523
500	169	66	-	31	650	128	565
600	153	59	7660	31	-	132	586
700	138	53	-	30	-	136	624
800	132	51	-	28	-	136	624

A description of the physical symbols

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

Technological properties

Name	The value
Weldability	Limited weldability. RDS, ADS submerged.
Склонность к отпускной хрупкости	Inclined.
The temperature of forging	Beginning - 1220 °C, end - 800 °C. the cross Sections up to 100 mm are cooled in air, 101-300 mm in the pit.
Flock-sensitive sensitivity	Sensitive.
Machinability	In hot-rolled condition with HB 177,blower SB=610 MPa Kn b.St.=0,95.
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 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 37÷43, and at a distance of 30 mm from the end - 24÷34.

Steel 20KHN3A

Designation

Description