Steel U12A
Designation
Name |
The value |
Designation GOST Cyrillic |
У12А |
Designation GOST Latin |
U12A |
Transliteration |
U12A |
The 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 stripes |
В23 |
GOST 103-2006 |
Sectional and shaped rolling |
В22 |
GOST 1133-71, GOST 2590-2006, GOST 2591-2006, GOST 2879-2006 |
Sectional and shaped rolling |
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 |
Tapes |
В34 |
GOST 21996-76, GOST 21997-76 |
Sheets and stripes |
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 |
The 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 characteristics
Section, mm |
t отпуска, °C |
sT|s0,2, MPa |
σB, MPa |
d5, % |
d4 |
y, % |
kJ/m2, кДж/м2 |
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 |
Section |
Section |
sT|s0,2 |
Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2% |
σB |
Limit short-term strength |
d5 |
Elongation after rupture |
d4 |
Elongation after rupture |
y |
The relative narrowing |
kJ/m2 |
Toughness |
HRC |
Rockwell hardness (indenter diamond spheroconical) |
HV |
The Vickers hardness |
Physical characteristics
Temperature |
Е, ГПа |
G, ГПа |
r, кг/м3 |
l, Вт/(м · °С) |
R, НОм · м |
a, 10-6 1/°С |
С, Дж/(кг · °С) |
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. |
Propensity to temper brittleness |
Tend not. |
Forging temperature |
Start - 1100 °C, the end - 750 °C. slow Cooling in air. |
Flock-sensitive sensitivity |
not sensitive. |
Workability by cutting |
In the annealed condition with HB 207 Kn TV.SPL.=1,0 Kn b.St.=0,9. |
Features of production |
Rod on the other 14-1-505-73 comes Beloretsky metallurgical plant. |
Grindability |
Good. |