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15X12VNMF steel

X27YU5T CRN70VMTUF CHN78T CRN70VMYUT CHN80TBU CRN35VT CHN70U CRN35VTU CHN77TUR 20X23H18 31Х19Н9МВБТ 40Х13 20Х13 20X25H20C2 40Х15Н7Г7Ф2МС 10X23H18 12Х25Н16Г7АР 15X12VNMF 20Х20Н14С2 37X12H8G8MFB 40X9C2 20X23H13 30Х13 40CR10CR2M 45Х14Н14В2М 13Х11Н2В2МФ

15X12VNMF steel

15Cr12VNMF Steel: Handbook of steels and alloys. Below is systematized information on the purpose, chemical composition, types of supply, substitutes, critical point temperature, physical, mechanical, technological and foundry properties for the grade — Steel 15Kh12VNMF.

General information on 15X12VNMF steel

Delivery type
Bar stock, including shaped: GOST 5949−75, GOST 2590−71, GOST 2591−71, GOST 2879−69, GOST 18968−73, GOST 19442−74. Calibrated bar GOST 7417−75, GOST 8559−75, GOST 8560−78. Grinded rod and silver GOST 14955−77. Strip GOST 4405−75, GOST 103−76, GOST 18968−73. Forged and forged blanks GOST 1133−71.
Application
Rotors, disks, blades, bolts, bandages, nuts, pins and other parts operating to 780 ° C. Steel heat-resistant, martensitic-ferritic class.

Chemical composition of steel 15Х12ВНМФ

Chemical element %
Vanadium (V) 0.15−0.30
Tungsten (W) 0.7−1.1
Silicon (Si), max. 0.4
Manganese (Mn) 0.5−0.9
Copper (Cu), not more than 0.30
Molybdenum (Mo) 0.5−0.7
Nickel (Ni) 0.4−0.8
Sulfur (S), max. 0.025
Titanium (Ti), not more than 0.2
Carbon (C) 0.12−0.18
Phosphorus (P), not more than 0.030
Chrome (Cr) 11.0−13.0

Mechanical properties of 15X12VNMF steel

Mechanical properties at elevated temperatures

t test,°C σ0, 2, MPa σB, MPa δ5, % ψ, % KCU, J/m2
Bar thickness 40−120 mm. Hardening at 1050 °C, oil. Tempering at 700 °C. At 20 °C NV 255−271.
20 700−730 830−870 15−18 55−59 93−118
300 600−620 720−730 14−15 59−63 127−147
400 570−590 670−680 13−14 55−62 137−147
500 520−570 550−570 14−15 59−78 118−147
550 455−470 500−520 18−19 78−79 127−137
600 350−370 370−395 20−23 79−88 132−147
650 275−315 295−340 26 87 152
Disc diameter 750−1020 mm, height 300 mm. Rotor forging with diameter 1140 mm. Quenching 1050 °C, oil. Tempering at 720 °C. (Tangential samples). At 20 °C NV 228−248
20 600−650 750−810 14−23 41−55 47−147
100 580−610 720−760 16−18 45−53 78−137
200 540−570 690−710 13−17 37−54 88−147
300 520−540 640−680 13−17 46−51 88−137
400 500−510 610−630   45−51 88−147
500 440−460 510−530 15−19 52−61 78−176
600 330−350 340−360 21−31 83−85 98−196

Mechanical properties of bars

Heat treatment, delivery condition Section, mm σ0, 2, MPa σB, MPa δ5, % ψ, % KCU, J/m2
Annealing at 900−950°C, cooling in the furnace. Tempering at 1000−1020°C, oil. Tempering 680−700°C, air. 60 590 740 15 45 59

Mechanical properties depending on heat treatment

Heat treatment, delivery condition σ0.2, MPa σB, MPa δ5, % ψ, % KCU, J/m2 HB
Disk diameter 700 mm, height 300 mm.
Heat soak 500 °C, 5000 h 600 790 21 57 56 241
Heat soak 600 °C, 5000 h 580 750 21 49 34 241
Rotor forging with a diameter of 1000 mm.
Heat soak 550 °C, 30000 h 660 810 17 44   262
Heat soak 600 °C, 30000 h 480 660 21 40   207
Heat soak 550 °C, 30000 h 630 780 14 42   255
Heat soak 600 °C, 30000 h 440 630 26 51   196

Mechanical properties in the long term strength test

Creep strength, MPa Creep rate, %/h t test,°C Ultimate long-term strength, MPa Test duration, h t test, h
98 1/100000 550 235 10000 550
88 1/100000 565 196 100000 550
69 1/100000 580 157 10000 580
54 1/100000 600 137 100000 580

Technological properties of 15X12VNMF steel

Forging temperature
The beginning 1230, the end 900. Sections up to 250 mm are subjected to annealing with one supercooling. Sections from 250 to 400 mm — annealing and two supercooling.
Weldability
hardly weldable. The electrode КТН-10 is used for welding, before welding a full heat treatment is carried out, after welding — tempering at 700 C for 5 hours or at 680 C for 10 hours, cooling with a furnace.
Machinability
at HB 230 Kυ dv.spl. = 1.1, Kυ b.st. = 0.5.

Temperature of critical points of 15X12VNMF steel

Critical point °С
Ac1 805
Ac3 870

Impact toughness of 15X12VNMF steel

Impact toughness, KCU, J/cm2

Delivery condition, heat treatment +20 -20 -40 -60
Disc diameter 750−1020 mm, height 300 mm. Rotor forging with diameter 1140 mm. Hardening 1050 C, oil. Tempering at 720 C. (Tangential samples) b0,2 = 600−650 MPa, bv = 750−810 MPa. 47−147 57 67 62

Hardness of steel 15Х12ВНМФ

σ-1, MPa n σB, MPa σ0, 2, MPa Heat treatment, state of steel
380 1Е+7 510 690 Tempering at 1050 C, oil. Tempering 700−720 C. The samples are smooth.
168 1Е+7 510 690 1050 C hardening, oil. Tempering 700−720 C. The samples are smooth. Sample with notch, radius at the apex of notch 0.75 mm.

Physical properties of 15X12VNMF steel

Temperature of test, °С 20 100 200 300 400 500 600 700 800 900
Modulus of normal elasticity, E, GPa 212 207 202 196 190 181 167      
Steel density, pn, kg/m3 7850 7830 7800 7780 7760 7730 7700 7670    
Thermal conductivity coefficient W/(m — °C)   25 25 26 26 27 27      
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) 10.5 10.8 11.1 11.4 11.6 11.8 11.9 12.0 10.7 11.6