18HGT steel is used: for the production of improved or cemented parts for critical applications, which require increased strength and toughness of core and high surface hardness, working under shock loads.

Note

Steel structural quality chromatorgraphy.

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 14-1-2118-77, TU 14-1-3238-81, TU 14-11-245-88, TU 14-1-3238-2006, TU 14-1-1271-75, 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
Blanks. Of the workpiece. Slabs	В31	OST 3-1686-90, TU 14-1-4944-90
Processing of metals by pressure. Forgings	В03	OST 5Р.9125-84, ST ЦКБА 010-2004
Sheets and strips	В33	TU 14-1-3571-83

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	V	Ti	Mo	W
GOST 4543-71	0.17-0.23	≤0.035	≤0.035	0.8-1.1	1-1.3	0.17-0.37	≤0.3	Rest	≤0.3	≤0.05	0.03-0.09	≤0.15	≤0.2

Fe is the basis.
According to GOST 4543-71 the content in high-quality steel is regulated: P≤0,025%; S≤0.025%; Сu≤0.30%; in high-grade steel: P≤0,025%; S≤0.015%; Сu≤0.25%.
According to TU 14-1-3238-81 the chemical composition is given for steel grade 18HGTA.

Mechanical properties

Section, mm	t отпуска, °C	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	d₄	y, %	KCU, kJ/m²	HB, MPa	HRC
Normalization at 930-960 °C + carburizing at 930-950 °C +quenching in oil with 825-840 °C + vacation at 180-200 °C
≤50	-	800	1000	9	-	-	-	≥285	57-63
Quenching in oil from 850 °C + vacation at 200 °C, air cooling
≤5	-	1320	1520	12	-	50	706	-	-
Quenching in oil at 880 °C + vacation
-	200	1150	1370	11	-	57	-	-	41
Normalization [82]
-	-	420	520	-	26	77	-	156	-
Cementation at 920-950 °C, air cooling + tempering in oil with 820-860 °C + vacation at 180-200 °C, air cooling
≤20	-	930	1180	10	-	50	765	300-341	53-63
Quenching in oil from 850 °C + vacation at 200 °C, air cooling
15-20	-	730	980	15	-	55	1108	-	30
Quenching in oil at 880 °C + vacation
-	300	1150	1330	10	-	57	-	-	41
Normalization [82]
-	-	360	460	-	24	78	-	-	-
Cementation at 920-950 °C, air cooling + tempering in oil with 820-860 °C + vacation at 180-200 °C, air cooling
20-60	-	780	980	9	-	50	765	240-300	57-63
Quenching in oil from 850 °C + vacation at 200 °C, air cooling
20-25	-	690	980	19	-	50	912	-	28
Quenching in oil at 880 °C + vacation
-	400	1150	1210	9	-	57	-	-	40
Normalization [82]
-	-	310	465	-	24	68	-	-	-
Quenching in oil from 850 °C + vacation at 200 °C, air cooling
5-15	-	930	1180	13	-	50	765	-	38
Quenching in oil at 880 °C + vacation
-	500	950	940	15	-	66	-	-	32
Normalization [82]
-	-	300	470	-	29	75	-	-	-
Quenching in oil at 880 °C + vacation
-	600	720	780	20	-	73	-	-	22
Normalization [82]
-	-	300	410	-	27	76	-	-	-
-	-	240	325	-	45	86	-	-	-
A sample with a diameter of 6 mm, length 30 mm, forged and normalized. The rate of deformation of 50 mm/min strain Rate of 0.03 1/s [81]
-	-	205	235	46	-	88	-	-	-
-	-	76	135	51	-	94	-	-	-
-	-	54	95	55	-	96	-	-	-
-	-	50	78	58	-	100	-	-	-
-	-	25	43	61	-	100	-	-	-
-	-	13	25	56	-	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
d₄	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	l, W/(m · °C)	a, 10^-6 1/°C	С, J/(kg · °C)
100	205	80	38	10	495
500	168	66	34	133	567
700	136	52	30	-	626

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
a	The coefficient of linear expansion

Technological properties

Name	The value
Weldability	welded without restriction (except chemical-thermally treated parts). Welding methods: SMAW, CCC.
Склонность к отпускной хрупкости	malosana
The temperature of forging	Start - 1200 °C, the end - of 800 °C. the cross Sections up to 250 mm are cooled in air, 251-350 mm - in the pit.
Flock-sensitive sensitivity	not sensitive
Machinability	After normalization with HB 156-159 and blower SB=530 MPa Kn TV.SPL.=1.1 Kn b.St.=1.0

Steel 18HGT

Designation

Description