Steel 18HGT

Designation

Name The value
Designation GOST Cyrillic 18ХГТ
Designation GOST Latin 18XGT
Transliteration 18HGT
By chemical elements 18CrMnTi

Description

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 sT|s0,2, MPa σU, 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
sT|s0,2 Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%
σU 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