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Steel 25Kh1MF

25Cr1MoV Steel

Steel 25Kh1MF: a classifier 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 brand — Steel 25Kh1MF.

General information on steel 25Kh1MF

Type of delivery
Round 25h1mf, bars, including shaped: GOST 20072−74, GOST 2590−71, GOST 2591−71. Calibrated bar GOST 7417−75, GOST 8559−75, GOST 8560−78. Strip GOST 103−76, GOST 4405−75, GOST 20072−74. Forged and forged blanks GOST 1133−71, GOST 20072−74.
Application .
Various parts operating at temperatures up to 540 ° C. Fasteners operating at temperatures from -40 ° C to +500 ° C.

Chemical composition of steel 25Kh1MF

Chemical element %
Vanadium (V) 0.15−0.30
Silicon (Si) 0.17−0.37
Manganese (Mn) 0.40−0.70
Copper (Cu), not more than 0.020
Molybdenum (Mo) 0.25−0.35
Nickel (Ni), not more than 0.30
Sulfur (S), not more than 0.025
Carbon (C) 0.22−0.29
Phosphorus (P), not more than 0.030
Chromium (Cr) 1.50−1.80

Mechanical properties of steel 25Kh1MF

Section, mm σ0, 2, MPa σB, MPa δ5, % ψ, % KCU, J/m2 HB
Rods: 880−900°C hardening, oil. Tempering 640−660°C, air.
90 735 880 14 50 59  
Bar stock: Quenching 930−950°C, oil. Tempering 620−660°C, air.
90 665 780 16 50 59  
Bar: Normalization 1000 °C, tempering 650 °C.
  810−870 940−980 17 51−58    
Forgings: quenching 860 °C, oil. Tempering 515 °C, air.
250 780 930 10 40 49 285−321
350 690 860 12 45 59 269−302
450 590 780 14 45 59 241−277
Forgings: quenching 930−950°C, oil. Tempering 620−660°C, air.
20−180 670 780 16 50 59  

Mechanical properties at elevated temperatures

t test,°C σ0, 2, MPa σB, MPa δ5, % ψ, %
annealing at 920°C
20 400 540 24 75
500 260 380 23 79
550 240 330 24 82
Quenching 930−950°C, oil. Tempering 620−660°C
20 790−1000 880−1050 16−19 60−64
400 610 710 17 68
450 590 690 17 71
500 580 620 19 75
550 490 550 20 78

Mechanical properties depending on tempering temperature

t tempering temperature, °C σ0, 2, MPa σB, MPa δ5, % ψ, % KCU, J/m2
910−920°C hardening, oil
540 1220 1270 13 58  
570 1190 1230 16 61  
600 1150 1190 18 61 78
630 1060 1120 19 62 78
660 880 960 19 69 127

Mechanical properties at 20 C, depending on heat treatment

Heat treatment, delivery condition σ0, 2, MPa σB, MPa δ5, % ψ, % KCU, J/m2
Hardening at 950 °C, oil. Tempering 620°C
Heat soaking at 450 °C, 3000 h. 940 1110 18 61 54
Heat soak 450 °C, 6000 h. 990 1160 17 55 44
Heat soak 500 °C, 3000 h. 980 1090 18 60 44−59
Heat soak 500 °C, 6000 h. 950 1070 17 60 49−54
Normalization 1000 °C, air. Tempering 650 °C,
Heat soak 450 °C, 3000 h. 800 970 15 52 41−49
Heat soak 500 °C, 3000 h. 870 980 15 60 41

Technological properties of 25Kh1MF steel

Forging temperature
The beginning 1180, the end 850. Sections up to 60 mm are cooled in stacks in the air, 61−200 mm are subjected to low-temperature annealing.
Weldability
Difficult-to-weld. Welding methods: TIG and ADS.
Machinability
In normalized and tempered state with NV? 300 Kυ dv.spl. = 0.70, K υ b.st. = 0.25.
Tendency to tempering ability
is not prone to
Flocculation sensitivity
sensitive

Temperature of critical points of 25Kh1MF steel

Critical point °С
Ac1 760
Ac3 840
Ar3 770
Ar1 685
Mn 345

Hardenability of steel 25Kh1MF

Distance from end face, mm / HRCe
5 10 15 20 25 30 40 50 60
45−50,5 42,5−49,5 38,5−48 35,5−46,5 34−44,5 32,5−41,5 31−39,5 30−39,5 29,5−39,5

Physical properties of steel 25Kh1MF

Test temperature,°C 20 100 200 300 400 500 600 700 800 900
Modulus of normal elasticity, E, GPa 213 207 204 194 187 176 164      
Torsional shear modulus of elasticity G, GPa 82 80 77 75 71 66 63      
Steel density, pn, kg/m3 7840   7790   7720   7650      
Thermal conductivity coefficient W/(m — °C)   40 39 38 37 36 35      
Electrical resistivity (p, Nm — m)   312 396 475 574 680 826      
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) 11.3 11.7 12.8 13.9 14.2 14.4        
Specific heat capacity (C, J/(kg -°C)) 462