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12X18H9T steel

12Cr18Ni9T Steel

Steel 12Cr18Ni9T: a classifier of steels and alloys. Below is systematized information on the purpose, chemical composition, types of supply, substitutes, critical point temperatures, physical, mechanical, technological and foundry properties for the grade - Steel 12X18H9T.

General information about 12X18H9T steel

The substitute for the following steel grade
10Х14Г14Н4Т, 12Х17Г9А4, 12Х18Н10Т.
Type of delivery
Krug 12h18n9t, 12h18n9t wire, bar stock, including shaped: GOST 5949−75, GOST 2590−71, GOST 2591−71, GOST 2879−69. Calibrated bar GOST 7417−75, GOST 8559−75, GOST 8560−78. Grinded rod and silver GOST 5949−75, GOST 14955−77, GOST 18907−73. Sheet thickness GOST 7350−77. GOST 4405−75 GOST 103−76 strip. Wire GOST 18143−72. Forgings and forged blanks GOST 1133−71, GOST 25054−81.
Application
Welded equipment, pipes, parts of furnace fittings, heat exchangers, muffles, parts of exhaust systems, sheet and sectional parts. Apparatuses and vessels operating at temperatures from -196 to 600 °C under pressure, and in the presence of aggressive media up to 350 °C. The steel is corrosion-resistant, heat-resistant austenitic class.

Chemical composition of steel 12Х18Н9Т

Chemical element %
Silicon (Si), not more 0.8
Manganese (Mn), not more than 2.0
Copper (Cu), not more than 0.30
Nickel (Ni) 8.0−9.5
Sulfur (S), not more than 0.020
Titanium (Ti) 0.6−0.8
Carbon ©, not more than 0.12
Phosphorus (P), not more 0.035
Chrome (Cr) 17.0−19.0

Mechanical properties of steel 12Х18Н9Т

Heat treatment, delivery condition Section, mm σ0, 2, MPa σB, MPa δ5, % ψ, %
Rods. Hardened at 1020−1100°C, air, oil, water. 60 196 540 40 55
Grinded bars, machined to the specified strength. 1−30   540−880 20  
Bulk rods <5   935    
Hot- or cold-rolled sheets. Hardened 1030−1080°C, water or air. >4 216 530 38  
Forgings. Tempering 1050−1100°C, air or water. <1000 216 510 35 40
Heat-treated wire 1−6   540−880 20  
Bulk wire 1−6   1080    

Mechanical properties at elevated temperatures

t test,°C σ0, 2, MPa σB, MPa δ5, % ψ, %
18−25 mm diameter bars. Hardening at 1050 °C, water
20 280 620 41 63
300 200 460 31 65
400 180 450 31 65
500 180 450 29 65
600 180 400 25 61
700 160 280 26 59
800 100 180 35 69
Sample diameter 10 mm, length 50 mm, rolled. Deformation rate 20 mm/minute. Strain rate 0.007 1/s.
800 155 200 27 57
900 110 120 41 90
1000 58 66 50 95
1100 35 38 66 99
1200 22 26 79 100
Sheet thickness 2 mm. Nagart with a degree of cold plastic deformation 60%
20 1290 1330 10  
300 970 1080 6  
500 780 870 10  
700 360 420 29  

Mechanical properties depending on degree of plastic deformation

Heat treatment, delivery condition σ0, 2, MPa σB, MPa δ5, %
Sheet. Hardened at 1050 °C, water.
Degree of compression 0% 280−400 550−650 40−50
30% compression rate 900 950 12
70% compression rate 1150 1250 3

Mechanical properties in the long term strength test

Creep strength, МPa Creep rate, %/h t test,°C Ultimate long-term strength, MPa Test duration, h t test, h
74−78 1/100000 600 186−235 10000 550
      132−167 10000 600
      137−196 100000 550
      98−127 100000 600

Technological properties of steel 12Х18Н9Т

Forging temperature
Beginning temperature 1200, ending temperature 850. Sections up to 350 mm are cooled in the air.
Weldability
Weldability without restriction. Welding methods: РДС electrodes ЦЛ-11, ЦЛ-15 (providing corrosion resistance), ЦТ-26 (used as heat-resistant without MKC requirements), ЕШС. The subsequent heat treatment is recommended.
Machinability by cutting
In the hardened condition at HB 169 and σB = 610 MPa Kυ of dv.solid. = 0,85, K υ b.st. = 0,35.

Impact toughness of steel 12Х18Н9Т

Impact toughness, KCU, J/cm2

Delivery condition, heat treatment +20 -70
The rod section of 18−25 mm. Hardened 1050 C, water. bv = 620 MPa, b0,2 = 280 MPa. 250 250

Endurance limit of steel 12Х18Н9Т

σ-1, MPa τ-1, MPa n
279   1Е+7
196−235 132  

Heat resistance of 12X18H9T steel

Medium Temperature,°C Depth, mm/year Resistance group or grade
Superheated steam 600 0,0018 2
Air 650 0,0022 2
Air 750 0,013 4

Physical properties of steel 12Х18Н9Т

Test temperature,°C 20 100 200 300 400 500 600 700 800 900
Modulus of normal elasticity, E, GPa 195 189 182 175 167 180 153 143 135  
Steel density, pn, kg/m3 7900 7860 7820 7780 7740 7690 7650 7600 7560 7510
Thermal conductivity coefficient W/(m - °C)   16 18 20 21 23 25 26 28 29
Electrical resistivity (p, nominal value - m) 725 792 861 920 976 1028 1075 1117 1149 1176
Test temperature,°C 20−100 20−200 20−300 20−400 20−500 20−600 20−700 20−800 20−900 20−1000
Coefficient of linear expansion (a, 10−6 1/°C) 16.0 17.0 17.6 18.0 18.3 18.6 18.9 19.3 19.5 20.1
Specific heat capacity (C, J/(kg -°C)) 469 486 498 511 519 528 532 544 548  

Sensitivity to embrittlement of 12X18H9T steel

Temperature, °C Time, h KCU, J/cm2
- Initial state 245
500 10000 186
550 20000 220
600 10000 215