By visiting this site, you accept the use of cookies. More about our cookie policy.

U7 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

U7 steel

Steel U7: 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 U7.

General information on steel U7

Grade substitute
steel У8.
Type of delivery
Sections, including shapes: 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 10234−77, GOST 21997−76. Strip GOST 103−76, GOST 4405−75. Forgings and forged blanks GOST 1435−74, GOST 4405−75, GOST 1133−71.
Application
The tool, which operates in conditions that do not cause heating of the working edge: chisels, chisels, hammers, metal cutting scissor blades, axes, cleavers, chisels, combination pliers, sledgehammers.

Chemical composition of steel U7

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) 0.66−0.73
Phosphorus (P), not more than 0.030
Chromium (Cr), not more than 0.20

Mechanical properties of steel U7

Mechanical properties

Heat treatment, delivery condition Section, mm σB, MPa δ4, %
Cold rolled annealed strip
  0,1−1,5 650 15
  1,5−4,0 750 10
Cold rolled clad strip.
Strength class H1 0,1−4,0 750−900  
Strength class H2 0,1−4,0 900−1050  
Strength class H3 0,1−4,0 1050−1200  
Cold-rolled annealed strip of the highest quality category.
  0,1−4,0 650 18

Mechanical properties depending on tempering temperature

t tempering temperature, °C σ0, 2, MPa σB, MPa ψ, % KCU, J/m2
Quenching for fine grain structure with cooling in water.
300 1370 1590 8 31
400 1180 1270 11 44
500 970 1090 13 73
600 830 980 17 93

Mechanical properties depending on test temperature

Heat treatment, delivery condition t test temperature,°C σB, MPa δ5, % ψ, % HB
Annealing or normalization
  100 690 16 30 200
  200 660 13 22 200
  300   18 20 200
  400 620 22 26 180
  500 460 27 34 155
  600 330 33 45 135
  700 205 38 60 110
Sample with diameter of 5 mm and length of 25 mm deformed and annealed. Strain rate 10 mm/minute. The strain rate is 0.007 1/s.
  700 105 64 90  
  800 94 65 100  
  900 63 60 100  
  1000 36 62 100  
  1100 22 65 100  
  1200 17 92 100  
Annealing.
Vizg=195 MPa 600   26 71  
Vizg=85 MPa 700   45 88  
Vizg=52 MPa 800   38 71  
Vizg=27 MPa 900   59 92  
Vizg=25 MPa 1000   58 98  
Vizg=20 MPa 1100   65 99  

Technological properties of steel U7

Forging temperature
The beginning 1180, the end 800. Cooling of blanks with a cross section of up to 100 mm in the air, 101−300 mm — in the pit.
Weldability
Not applicable for welded structures.
Machinability
In the annealed state at HB 187 and σB = 620 MPa Kυ tv.spl. = 1.2, K υ b.st. = 1.1.
Tendency to tempering capacity
is not inclined
Floc-sensitivity
not sensitive
Grindability
good

Temperature of critical points of steel U7

Critical point °С
Ac1 730
Ac3 770
Ar1 700
Mn 280

Steel hardness U7

Delivery condition, heat treatment regime HRCe surface HB
Heat-treated steel. Hardened 800−820 C, water. St. 63 187
Tempering 820 C, water. Tempering 160−200 C. 60−63  
Tempering at 820 °C with water. Tempering 200−300 C. 54−60  
Tempering at 820 °C with water. Tempering 300−400 C. 43−54  
Tempering at 820 °C with water. Tempering 400−500 C. 35−43  

Hardenability of steel U7

Tempering at 800 °C.

Distance from end face, mm / HRCe
2.5 5 7.5 10 15 20 25 30
43,5 37 35 34 32 28,5 22 20
Crit. dia. in water, mm Crit. dia. in oil, mm
15−20 4−6

Physical properties of steel U7

Test temperature, °С 20 100 200 300 400 500 600 700 800 900
Steel density, pn, kg/m3 7830                  
Thermal conductivity coefficient W/(m — °C) 46 46   41     33     29
Electrical resistivity (p, nominal value — m) 130                  
Test temperature,°C 20−100 20−200 20−300 20−400 20−500 20−600 20−700 20−800 20−900 20−1000
Specific heat capacity (C, J/(kg -°C))     580 664 819 970 710 706 685  

Heat resistance, red resistance of steel U7

Heat resistance

Temperature, °C Time, h Hardness, HRCэ
150−160 1 63
20−220 1 59