Steel U7

Designation

Name The value
Designation GOST Cyrillic У7
Designation GOST Latin U7
Transliteration U7
By chemical elements 7

Description

Steel u7 is used: for the manufacture of tools for working wood (axes, kolunov, chisels, bits); pneumatic tools small size (chisels, swages, dies); forging dies; needle wire; machinist’s tools (hammers, sledge hammers, drifts, screwdrivers, compound pliers, nippers, oblique cutting pliers, etc.).

Standards

Name Code Standards
Tape В34 GOST 10234-77
Sheets and strips В23 GOST 103-2006
Bars and shapes В22 GOST 1133-71, GOST 2590-2006, GOST 2591-2006, GOST 2879-2006
Bars and shapes В32 GOST 1435-99, GOST 5210-95, GOST 7417-75, GOST 8559-75, GOST 8560-78, GOST 14955-77, TU 14-11-245-88, TU 14-1-1271-75
Sheets and strips В33 GOST 4405-75
Steel wire medium and high carbon В72 GOST 5468-88, GOST 9389-75

Chemical composition

Standard C S P Mn Cr Si Ni Fe Cu
GOST 1435-99 0.65-0.74 ≤0.028 ≤0.03 0.17-0.33 ≤0.2 0.17-0.33 ≤0.25 Rest ≤0.25
Fe is the basis.
According to GOST 1435-99, the mass fraction of chromium, nickel and copper is indicated for 1 group of metal products. The mass fraction of sulfur in steel obtained by the electroslag remelting method should not exceed 0.013%. In the metal products of the third group, the mass fraction of Cr ≤ 0.20-0.40%, Ni ≤ 0.25%, Cu ≤0.25%. In metal products of the 1 st and 3 rd groups, made of steel obtained by scrap-process, the mass fractions of nickel, copper and chromium are increased by 0.05% of each element as compared to those in the table. In a metal designed for the manufacture of cold-rolled strip, an increase in the mass fraction of nickel, copper and chromium is not allowed.

Mechanical properties

Section, mm t отпуска, °C sT|s0,2, MPa σU, MPa d5, % d4 d y, % KCU, kJ/m2 HB, MPa
Tape flatted average strength of 0.1-4.0 mm according to GOST 10234-77 in the state of delivery (indicated delivery)
- - - 780-1270 - - - - - -
- - - 780-930 - - - - - -
- - - 930-1080 - - - - - -
- - - 1080-1230 - - - - - -
- - - ≤780 - - ≥10 - - -
- - - ≤570 - - - - - -
Annealed cold-rolled tape of the highest quality
0.1-1.5 - - ≤650 - ≥15 - - - -
Quenching in fine-grained structure with cooling in water + Vacation
- 300 ≥1370 ≥1590 - - - ≥8 ≥310 -
A sample with a diameter of 5 mm and a length of 25 mm deformed and annealed. A strain rate of 10 mm/min strain Rate 0,007 1/C
- - - ≥105 ≥64 - - ≥90 - -
Annealed cold-rolled tape of the highest quality
1.5-4 - - ≤750 - ≥10 - - - -
Quenching in fine-grained structure with cooling in water + Vacation
- 400 ≥1180 ≥1270 - - - ≥11 ≥440 -
A sample with a diameter of 5 mm and a length of 25 mm deformed and annealed. A strain rate of 10 mm/min strain Rate 0,007 1/C
- - - ≥94 ≥65 - - ≥100 - -
Quenching in fine-grained structure with cooling in water + Vacation
- 500 ≥970 ≥1090 - - - ≥13 ≥730 -
A sample with a diameter of 5 mm and a length of 25 mm deformed and annealed. A strain rate of 10 mm/min strain Rate 0,007 1/C
- - - ≥63 ≥60 - - ≥100 - -
Quenching in fine-grained structure with cooling in water + Vacation
- 600 ≥830 ≥980 - - - ≥17 ≥930 -
A sample with a diameter of 5 mm and a length of 25 mm deformed and annealed. A strain rate of 10 mm/min strain Rate 0,007 1/C
- - - ≥36 ≥62 - - ≥100 - -
- - - ≥22 ≥65 - - ≥100 - -
- - - ≥17 ≥92 - - ≥100 - -
Annealing
- - - - ≥26 - - ≥71 - -
- - - - ≥65 - - ≥99 - -
Cold-rolled steel strip sagatovna (specified strength class)
0.1-4 - - 750-900 - - - - - -
Annealing
- - - - ≥58 - - ≥98 - -
Cold-rolled steel strip sagatovna (specified strength class)
0.1-4 - - 900-1050 - - - - - -
Annealing
- - - - ≥59 - - ≥92 - -
Cold-rolled steel strip sagatovna (specified strength class)
0.1-4 - - 1050-1200 - - - - - -
Annealing
- - - - ≥38 - - ≥71 - -
- - - - ≥45 - - ≥88 - -
Annealing or normalizing
- - - ≤690 ≥16 - - ≥30 - ≤200
- - - ≤660 ≥13 - - ≥22 - ≤200
- - - ≤640 ≥18 - - ≥20 - ≤200
- - - ≤620 ≥22 - - ≥26 - ≤180
- - - ≤460 ≥27 - - ≥34 - ≤155
- - - ≤330 ≥33 - - ≥45 - ≤135
- - - ≤205 ≥38 - - ≥60 - ≤110

Description mechanical marks

Name Description
sT|s0,2 Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%
σU Limit short-term strength
d5 Elongation after rupture
d4 Elongation after rupture
d Elongation after rupture
y The relative narrowing
KCU Toughness
HB Brinell hardness number

Physical characteristics

Temperature r, kg/m3 l, W/(m · °C) R, Mr. · m С, J/(kg · °C)
0 7830 46 130 -
20 7830 46 130 -
100 - 46 - -
300 - 41 - 580
600 - 33 - 970
900 - 29 - 706
400 - - - 664
500 - - - 819
700 - - - 710
800 - - - 706
1100 - - - 685

A description of the physical symbols

Name Description
Е The normal elasticity modulus
G Modulus of elasticity shear torsion
r Density
l Coefficient of thermal conductivity
R UD. the resistivity
a The coefficient of linear expansion
С Specific heat

Technological properties

Name The value
Weldability does not apply to welded structures.
Склонность к отпускной хрупкости tend not
The temperature of forging Start - 1180 °C, the end - of 800 °C. the cooling of the workpiece cross-section up to 100 mm in the air, 101-300 mm in the pit.
Flock-sensitive sensitivity not sensitive
Machinability In the annealed condition with HB 187 and blower SB=620 MPa Kn TV.SPL.=1.2 Kn b.St.=1.1
Sanding behaviour good