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Steel 40KHFA

Description

Steel 40KHFA

Steel 40HFA: brand of steels and alloys. Below is a systematized information on the purpose, chemical composition, types of supplies, substitutes, temperature of critical points, physical, mechanical, technological and casting properties for the grade — Steel 40HFA.

General information about steel 40HFA

Substitute brand
Steel: 40X, 65G, 50XFA, 30X3MF.
Delivery type
Long products, including shaped: GOST 4543−71, GOST 259071, GOST 2591−71, GOST 2879−69. Calibrated bar GOST 7417−75, GOST 8559−75, GOST 8560−78, GOST 1051−73. Polished bar and silver bar GOST 14955−77. Strip GOST 103−76. Forgings and forged billets GOST 1133−71, GOST 8479−70.
Application
Improved condition — splined shafts, rods, set screws, traverses, excavator shafts and other parts operating at temperatures up to 400 ° C; after hardening and low tempering — worm shafts and other parts of increased wear resistance.

Chemical composition of steel 40HFA

Chemical element %
Vanadium (V) 0.10−0.18
Silicon (Si) 0.17−0.37
Manganese (Mn) 0.50−0.80
Copper (Cu), no more 0.30
Nickel (Ni), no more 0.30
Sulfur (S), no more 0.025
Carbon (C) 0.37−0.44
Phosphorus (P), no more 0.025
Chromium (Cr) 0.8−1.1

Mechanical properties of steel 40HFA

Mechanical properties

Heat treatment, delivery condition Section, mm σ 0.2, MPa σ B, MPa δ 5 ,% ψ,% KCU, J / m 2 HB HRC e
Bar. Hardening 880 ° С, oil. Vacation 650 ° C, water or oil
  25 730 880 ten 50 88    
Forgings. Hardening. Vacation.
KP 395 100−300 395 615 fifteen 40 54 187−229  
KP 395 300−500 395 615 thirteen 35 49 187−229  
KP 490 100−300 490 655 thirteen 40 54 212−248  
KP 540 <100 540 685 fifteen 45 59 223−262  
KP 540 100−300 540 685 thirteen 40 49 223−263  
Bar. Hardening 860−880 ° С, oil. Vacation 200−230 ° С, oil.
  <40 1270 1570   35 39   49−53

Mechanical properties at elevated temperatures

test t, ° C σ 0.2, MPa σ B, MPa δ 5 ,% ψ,%
Hardening 850 ° С, oil. Vacation 640 ° С
20 840 920 26 63
200 800 900 22 46
300 740 840 eighteen 35
400 710 850 28 50
500 400 490 thirty 65
600   370 51 80

Mechanical properties depending on the tempering temperature

vacation t, ° С σ 0.2, MPa σ B, MPa δ 5 ,% ψ,% KCU, J / m 2 HRC e
Hardening 850 ° С, oil. Cooling after tempering from 500 ° C in water.
200 1490 1860 fourteen 43 49 51
300 1450 1650 fifteen thirty thirty 49
400 1270 1360 fourteen 39 39 46
500 1100 1160 fifteen 61 61 42
600 880 960 19 98 98 34

Mechanical properties depending on the section

Heat treatment, delivery condition Section, mm σ 0.2, MPa σ B, MPa δ 5 ,% ψ,% KCU, J / m 2
Hardening 850 ° C, water. Vacation 600 ° C, air. (Samples are tangential)
Sample cutting location — center 50 900 940 fifteen 45 69
Sample cutting location — center 80 810 890 eleven 33 39
Sample cutting location — center 120 710 860 12 37 64
Sample cutting location — center 160 610 830 fifteen 46 45
Sample cutting place — 1 / 2R 160 710 850 sixteen 44 47
Sample cutting location — center 200 490 710 17 49 57
Sample cutting place — 1 / 2R 200 510 800 eighteen 49 47
Sample cutting location — center 240 490 710 eighteen 51 71
Sample cutting place — 1 / 2R 240 570 770 19 50 54
Sample cutting location — edge 240 700 830 17 49 61

Technological properties of steel 40HFA

Forging temperature
The beginning is 1250, the end is 860−800. Sections up to 200 mm are cooled in a mold, 201−300 mm — with a furnace.
Weldability
difficult to weld. Welding methods: RDS — heating and subsequent heat treatment are required. KTS — subsequent heat treatment is required.
Machinability by cutting
After quenching and tempering at HB? 241, K υ tv.spl. = 0.75, K υ b.st. = 0.65.
Tendency to release ability
inclined
Flock sensitivity
sensitive

Temperature of critical points of steel 40HFA

Critical point ° C
Ac1 760
Ac3 800
Ar3 725
Ar1 680
Mn 214

Impact strength of steel 40HFA

Impact strength, KCU, J / cm 2

Delivery status, heat treatment +20 -20 -70
Ordering 850 С, oil. Vacation 600 C. 92 61 55

Endurance limit of steel 40HFA

σ -1, MPa τ -1, MPa n σ B, MPa Heat treatment, steel condition
480   1E + 6 1220 Tempering 880 C, oil. Vacation 230 S. NV 387
421   1E + 6 990 Tempering 880 C, oil. Vacation 550 S. NV 288
372 265 1E + 6 960 Tempering 880 C, oil. Vacation 650 S. NV 258

Hardenability of steel 40HFA

Hardness, HRC

Distance from the end, mm / HRC e
1.5 3 4.5 6 nine 12 fifteen eighteen 27 39
51.5−60.5 51.5−59.5 50.5−58.5 48−57.5 39.5−54 35−50.5 34−46.5 32.5−43 30.5−39 27−39

Physical properties of steel 40HFA

Test temperature, ° С 20 100 200 300 400 500 600 700 800 900
Normal elastic modulus, E, GPa 215 212 205 199 182 173 166 144 135  
Torsional shear elastic modulus G, GPa 84 83 80 77 71 66 64 56 52  
Density of steel, pn, kg / m 3 7810                  
Thermal conductivity coefficient W / (m ° С) 37 37 37 36 33 31 31 thirty 28  
Test temperature, ° С 20−100 20−200 20−300 20−400 20−500 20−600 20−700 20−800 20−900 20−1000
Linear expansion coefficient (a, 10−6 1 / ° С) 12.1 12.6 13.0 13.3 13.8 14.2 14.6 11.8    
Specific heat (C, J / (kg ° C)) 466 508 529 563 592 621 634 664    

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