Steel U12A

Designation

Name The value
Designation GOST Cyrillic У12А
Designation GOST Latin U12A
Transliteration U12A
By chemical elements 12

Description

Steel U12A is used: for the manufacture of cores; hand taps, files, metal scrapers; parts dies of cold forming, trimming and punching of small size and no transitions in the cross section; cold forging punches and dies for small sizes; calibers simple form and low accuracy classes; tools with low wear resistance at moderate and high specific pressure (without heating the cutting edge): nail files, razor blades and knives, sharp surgical tools, scrapers, engraving tools; cold-rolled heat-treated ribbon with a thickness of 0.05 to 1.30 mm and rolled heat-treated strip thickness 0.15−2.00 mm for the manufacture of spring details and springs, with the exception of clockwork.

Standards

Name Code Standards
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 14-1-505-73, TU 14-11-245-88, TU 14-1-1271-75
Tape В34 GOST 21996-76, GOST 21997-76
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 1.1-1.29 ≤0.018 ≤0.025 0.17-0.28 ≤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 2nd group, the mass fraction of Cr ≤ 0.12%, Ni ≤ 0.12%, Cu ≤0.20% and their total mass fraction ≤ 0.40%. 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.
According to TU 14-1-505-73, by agreement of the parties for special purpose hardware, steel should be supplied with reduced content limits of elements without treatment with synthetic slag and purging with argon.

Mechanical properties

Section, mm t отпуска, °C sT|s0,2, MPa σU, MPa d5, % d4 y, % KCU, kJ/m2 HRC HV, MPa
Tape cold-rolled heat-treated (0,05-1,30 mm) for spring parts and springs according to GOST 21996-76 and flattened strip (0,15-2,00 mm) according to GOST 21997-76 (listed group strength tape)
- - - 1270-1570 - - - - - 375-485
- - - 1580-1860 - - - - - 486-600
- - - ≥1860 - - - - - ≥600
Annealed cold-rolled tape of the highest quality
0.08-3 - - ≤750 - ≥10 - - - -
Samples section 21-30 mm. Quenching in water 810-830 °C + Vacation
- 400 ≥1370 ≥1570 ≥9 - ≥24 ≥20 ≥52 -
A sample with a diameter of 5 mm and a length of 25 mm, the deformed and annealed. The rate of deformation of 10 mm/min strain Rate 0,007 1/C
- - - ≥105 ≥60 - ≥68 - - -
Samples section 21-30 mm. Quenching in water 810-830 °C + Vacation
- 500 ≥880 ≥1040 ≥11 - ≥30 ≥29 ≥40 -
A sample with a diameter of 5 mm and a length of 25 mm, the deformed and annealed. The rate of deformation of 10 mm/min strain Rate 0,007 1/C
- - - ≥100 ≥52 - ≥96 - - -
Samples section 21-30 mm. Quenching in water 810-830 °C + Vacation
- 600 ≥650 ≥760 ≥18 - ≥52 ≥44 ≥26 -
A sample with a diameter of 5 mm and a length of 25 mm, the deformed and annealed. The rate of deformation of 10 mm/min strain Rate 0,007 1/C
- - - ≥60 ≥40 - ≥100 - - -
- - - ≥34 ≥65 - ≥100 - - -
- - - ≥18 ≥74 - ≥100 - - -
- - - ≥15 ≥92 - ≥100 - - -
Rolled steel. Annealing (at 20 °C HB=207)
- - ≥325 590-690 ≥28 - 45-55 - - -
- - ≥320 ≥570 ≥23 - ≥47 - - -
- - ≥310 ≥450 ≥41 - ≥60 - - -
- - ≥110 ≥140 ≥56 - ≥74 - - -
- - ≥59 ≥76 ≥56 - ≥82 - - -
- - ≥53 ≥72 ≥59 - ≥85 - - -
- - ≥34 ≥40 ≥52 - ≥91 - - -
- - ≥20 ≥28 ≥55 - ≥98 - - -

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
y The relative narrowing
KCU Toughness
HRC Rockwell hardness (indenter diamond spheroconical)
HV The Vickers hardness

Physical characteristics

Temperature Е, HPa G, HPa r, kg/m3 l, W/(m · °C) R, Mr. · m a, 10-6 1/°C С, J/(kg · °C)
0 209 82 7830 - - - -
100 205 80 7809 45 252 105 469
200 200 78 7781 43 333 118 503
300 193 75 7749 40 430 126 519
400 185 72 7713 37 540 134 536
500 178 69 7675 35 665 141 553
600 166 63 7634 32 802 148 720
700 - - 7592 28 964 153 611
800 - - 7565 24 1152 15 712
900 - - 7489 25 1196 - -
1000 - - - - - 163 703
1200 - - - - - 168 699

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

Technological properties

Name The value
Weldability Does not apply to welded structures. Method of welding - CCC.
Склонность к отпускной хрупкости Tend not.
The temperature of forging Start - 1100 °C, the end - 750 °C. slow Cooling in air.
Flock-sensitive sensitivity not sensitive.
Machinability In the annealed condition with HB 207 Kn TV.SPL.=1,0 Kn b.St.=0,9.
Particularities of production of goods Rod on the other 14-1-505-73 comes Beloretsky metallurgical plant.
Sanding behaviour Good.