18KH2N4MA steel is used: for the manufacture of critical parts, which are requirements of high strength, toughness and wear resistance, and for parts exposed to high vibration and dynamic loads after the carburizing and improvements; piping details with quenching in oil and tempering in oil or air; seamless tubes for aircraft; inlet valves, bolts, pins and other critical parts operating in corrosive environment at elevated temperatures (+300−400 °C). Steel can be used at temperatures from -70 °C to +450 °C.

Note

Steel high-quality structural romancelatina.
Case hardening steel.

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 10702-78, GOST 14955-77, TU 14-1-2118-77, TU 14-1-2591-79, TU 14-1-950-74, TU 14-11-245-88, TU 14-1-1271-75, TU 14-1-1971-76, 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, TU 24-00.13.034-89, ST ЦКБА 010-2004
Classification, nomenclature and General rules	В20	OST 1 90005-91
Blanks. Of the workpiece. Slabs	В31	OST 3-1686-90, TU 14-1-1265-75, TU 14-1-4944-90, TU 1-92-156-90
Thermal and thermochemical treatment of metals	В04	ST ЦКБА 026-2005
Steel cylinders	В66	TU 14-159-257-98
Steel pipes and fittings to them	В62	TU 14-3-367-75, TU 14-3-572-77

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	V	Ti	Mo
GOST 4543-71	0.14-0.2	≤0.025	≤0.025	0.25-0.55	1.35-1.65	0.17-0.37	4-4.4	Rest	≤0.3	≤0.05	≤0.06	0.3-0.4

Fe is the basis.
GOST 4543-71 regulates the content of high-quality steel: P≤0,025%; S≤0.015%; Сu≤0.25%. When the alloying Mo is replaced with W, the steel has the designation 18Х2Н4ВА.
According to TU 14-1-950-86 the chemical composition is given for steel grade 18H2N4MA.

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
300-500	-	≥685	≥835	≥11	≥33	≥383	262-311	-
100-300	-	≥735	≥880	≥12	≥35	≥481	277-321	-
≤100	-	≥785	≥930	≥12	≥40	≥579	293-331	-
Quenching in oil from 850 °C + vacation
-	200	≥1170	≥1470	≥12	≥64	≥1118	-	-
-	300	≥1140	≥1390	≥12	≥64	≥961	-	-
-	400	≥1040	≥1280	≥12	≥63	≥844	-	-
-	500	≥950	≥1180	≥13	≥66	≥903	-	-
-	600	≥710	≥940	≥19	≥73	≥1795	-	-
Quenching in water from 860 °C to + vacation at 200 °C (named place of clippings sample)
60-80	-	≥1250	≥1390	≥12	≥45	-	-	≥45
Quenching in oil at 880 °C to + vacation at 560 °C
-	-	≥1090	≥1240	≥12	≥61	-	-	-
Gradation of performance properties of the finished heat-treated parts for OST 1 90005-91
-	-	-	1040-1270	-	-	-	302-363	33-39
Steel calibrated and calibrated with special surface finish, hot rolled and hot rolled with special surface finish
-	-	-	-	-	-	-	≤269	-
Quenching in water from 860 °C to + vacation at 200 °C (named place of clippings sample)
80-100	-	≥1210	≥1360	≥13	≥57	-	-	≥44
Quenching in oil at 880 °C to + vacation at 560 °C
-	-	≥1060	≥1190	≥12	≥60	-	-	-
Gradation of performance properties of the finished heat-treated parts for OST 1 90005-91
-	-	-	-	-	-	-	321-415	31-43.5
Blank pieces of pipe fittings. Quenching in oil the oil from 845-875 °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
200	620-650	640-735	≥835	≥13	≥50	≥882	248-293	-
Quenching in water from 860 °C to + vacation at 200 °C (named place of clippings sample)
100-120	-	≥1240	≥1340	≥12	≥42	-	-	≥41
Quenching in oil at 880 °C to + vacation at 560 °C
-	-	≥1050	≥1200	≥14	≥64	-	-	-
Forgings. Anneal at 890-910 °C, cooling with the furnace
100-300	-	≥390	≥620	≥10	≥25	-	≥265	-
Quenching in water from 860 °C to + vacation at 200 °C (named place of clippings sample)
25-40	-	≥1220	≥1420	≥13	≥66	-	-	≥45
Quenching in oil at 880 °C to + vacation at 560 °C
-	-	≥960	≥1060	≥14	≥69	-	-	-
Rolled steel. Cementation at 920-950 °C + normalization at 900-950 °C, air cooling + tempering in oil 900-950 °C + dual a vacation at 630-650 °C, air cooling
60-80	-	≥1270	≥1370	≥12	-	≥863	321-400	≥57
Quenching in water from 860 °C to + vacation at 200 °C (named place of clippings sample)
40-60	-	≥1280	≥1420	≥13	≥61	-	-	≥45
Quenching in oil at 880 °C to + vacation at 560 °C
-	-	≥810	≥880	≥14	≥70	-	-	-
Quenching in oil from 860 °C to + vacation at 200 °C (named place of clippings sample)
60-80	-	≥1130	≥1250	≥12	≥54	-	-	≥42
Bars and strip hot rolled and forged. Annealing in air with 850-870 °C + Vacation, air cooling
	525-575	≥785	≥1030	≥12	≥50	≥1180	321-376	-
Quenching in oil at 880 °C to + vacation at 560 °C
-	-	≥710	≥750	≥16	≥73	-	-	-
Quenching in oil from 860 °C to + vacation at 200 °C (named place of clippings sample)
80-100	-	≥1100	≥1230	≥15	≥63	-	-	≥40
Bars and strip hot rolled and forged. Annealing in air with 850-870 °C + Vacation, air cooling
	150-170	≥835	≥1130	≥11	≥50	≥981	331-388	-
A sample with a diameter of 6 mm, length 30 mm, laminated. The rate of deformation of 16 mm/min strain Rate of 0.009 1/s.
-	-	≥225	≥265	≥31	≥69	-	-	-
Quenching in oil from 860 °C to + vacation at 200 °C (named place of clippings sample)
100-120	-	≥1090	≥1220	≥13	≥60	-	-	≥41
Bars and strip hot rolled and forged. Bars and strip hot rolled and forged. Annealing in air from 940-960 °C + Second quenching in air, 850-870 °C + Vacation, air cooling
	150-170	≥835	≥1130	≥11	≥50	≥981	341-388	-
A sample with a diameter of 6 mm, length 30 mm, laminated. The rate of deformation of 16 mm/min strain Rate of 0.009 1/s.
-	-	≥73	≥130	≥35	≥34	-	-	-
Quenching in oil from 860 °C to + vacation at 200 °C (named place of clippings sample)
25-40	-	≥1070	≥1300	≥14	≥69	-	-	≥43
A sample with a diameter of 6 mm, length 30 mm, laminated. The rate of deformation of 16 mm/min strain Rate of 0.009 1/s.
-	-	≥55	≥79	≥22	≥23	-	-	-
Quenching in oil from 860 °C to + vacation at 200 °C (named place of clippings sample)
40-60	-	≥1110	≥1250	≥15	≥62	-	-	≥41
A sample with a diameter of 6 mm, length 30 mm, laminated. The rate of deformation of 16 mm/min strain Rate of 0.009 1/s.
-	-	≥41	≥55	≥31	≥36	-	-	-
-	-	≥24	≥36	≥63	≥100	-	-	-
-	-	≥20	≥25	≥46	≥100	-	-	-

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	r, kg/m³	l, W/(m · °C)	a, 10^-6 1/°C
0	200	7950	-	-
100	165	7930	36	117
200	141	7900	36	122
500	-	7800	34	135
600	-	7760	33	135

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	Difficult weldability. Welding methods: SMAW, ADS submerged arc, electroslag welding. Necessary preheating and subsequent heat treatment.
Склонность к отпускной хрупкости	Tend not.
The temperature of forging	Start - 1200 °C, the end - of 800 °C. slow Cooling to 150 °C with subsequent high vacation no later than 4-6 h.
Flock-sensitive sensitivity	Sensitive.
Machinability	When 277-321 HB blower SB=880 MPa Kn TV.SPL.=0,72 Kn b.St.=0,63.

Steel 18KH2N4MA

Designation

Description