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U12 steel

R6M5K5 Р18 R9M4K8 Р9 45CRNIM 60XH 75CSMF 9Х2 55Х 60CSMF 7X2CMF 9X2MF 60CR2SMF 75CRM 90XMF 60XG 75CRMOV 90XF CB4F 9XVG. CVG 9HS 9Х1 У10 У12 У7 U10A U12A U7A У8 U8A U9A У9 27Х2Н2М1Ф 4X5MFS 6XV2C 7XG2VMF Х12 X12MF 40X5MF 4XV2C 5CHEV2C 6CVG X12VM X12F1 3CR2V8F 4CMFS 5CGM 6HS 8Х3 X6VF. 3Х2Н2МВФ 4Х2НМФ 4X5MF1S 5CRNIM 7Х3

U12 steel

Steel U12: Handbook 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 U12.

General information on steel U12

Substitute for the grade
Of steel grade: У10А, У11А, У10, У11.
Type of delivery
Sections including shaped: GOST 1435−74, GOST 2590−71, GOST 2591−71, GOST 2879−69. Calibrated rod GOST 1435−74, GOST 7417−75, GOST 8559−75, GOST 8560−78. Grinded rod and silversilver GOST 1435−74, GOST 14955−77. Tape GOST 2283−79, GOST 21997−76. Tape GOST 103−76, GOST 4405−75. Forgings and forged blanks GOST 1435−74, GOST 4405−75, GOST 1133−71.
Application
Cutting tools operating under conditions that do not cause the cutting edge heat: hand taps, taps small machine, dies for krupps, small reamers, files, measuring tools simple form: smooth caliber, staples.

Chemical composition of steel U12

Chemical element %
Silicon (Si) 0.17−0.33
Manganese (Mn) 0.17−0.33
Copper (Cu), not more 0.25
Nickel (Ni), not more than 0.25
Sulfur (S), not more than 0.028
Carbon (C) 1.16−1.23
Phosphorus (P), not more than 0.030
Chromium (Cr), not more than 0.20

Mechanical properties of U12 steel

Mechanical properties depending on tempering temperature

t tempering temperature, °C σ0.2, MPa σB, MPa δ5, % ψ, % KCU, J/m2 HRCe
Samples with the cross-section of 21−30 mm. 810−830°C hardening, water.
400 1370 1570 9 24 20 52
500 880 1040 11 30 29 40
600 650 760 18 52 44 26

Mechanical properties as a function of test temperature

t test temperature,°C σ0, 2, MPa σB, MPa δ5, % ψ, % KCU, J/m2
Annealing. At 20 °C NV 207
20 325 590−690 28 45−55 27
200   570 23 47 73
400 310 450 41 60 69
600 110 140 56 74 62
700 59 76 56 82 356
800 53 72 59 85 323
900 34 40 52 91 225
1000 20 28 55 98 157
Sample 5 mm in diameter and 25 mm in length, deformed and annealed. Deformation rate of 10 mm/minute. Deformation rate 0.007 1/s
700   105 60 68  
800   100 52 96  
900   60 40 100  
1000   34 65 100  
1100   18 74 100  
1200   15 92 100  

Technological properties of steel U12

Forging temperature
Beginning 1100, end 750. Delayed cooling in the air.
Weldability
Not applicable for welded structures. Welding procedure is CTS.
Machinability
In the annealed condition at HB 207 Kυ of tw.spl. = 1.0, Kυ b.st. = 0.9.
Tendency to tempering ability
is not prone
Floc-sensitivity
not sensitive
Grindability
good

Temperature of steel U12 critical points

Critical point °С
Ac1 730
Ac3 820
Ar1 700
Mn 200

Hardness of steel U12

Delivery condition, heat treatment regime HRCэ surface
Samples with cross section of 21−30 mm. Hardening 810−830 C, water. Tempering at 160−180 С. 62−64
Samples with the cross section of 21−30mm. Tempering at 810−830°C with water. Tempering at 180−220°C. 59−63
Samples with the cross section of 21−30 mm. Tempering at 810−830°C with water. Tempering at 200−270°C. 55−61
Samples with the cross section of 21−30 mm. Tempering at 810−830°C with water. Tempering at 450−500 C. 37−47

Hardenability of steel U12

Distance from the end face, mm / HRCe
 
 
Heat treatment Crit. dia. in water, mm Crit. dia. in oil, mm Crest hardness, HRCe
Hardening 10−20 4−6 61
760 C hardening 20   42−66

Physical properties of steel U12

Test temperature, °С 20 100 200 300 400 500 600 700 800 900
Modulus of normal elasticity, E, GPa 209 205 200 193 185 178 166      
Torsional shear modulus of elasticity G, GPa 82 80 78 75 72 69 63      
Steel density, pn, kg/m3 7830 7809 7781 7749 7713 7675 7634 7592 7565 7489
Thermal conductivity coefficient W/(m — °C)   45 43 40 37 35 32 28 24 25
Electrical resistivity (p, nominal value — m)   252 333 430 540 665 802 964 1152 1196
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 11.8 12.6 13.4 14.1 14.8 15.3 15.0 16.3 16.8
Specific heat capacity (C, J/(kg -°C)) 469 503 519 536 553 720 611 712 703 699

Heat resistance, red resistance of steel U12

Heat resistance

Temperature, °C Time, h Hardness, HRCэ
150−160 1 63
200−250 1 59