Steel A75 (У7АВ)
Designation
| Name |
The value |
| Designation GOST Cyrillic |
А75 |
| Designation GOST Latin |
A75 |
| Transliteration |
A75 |
| The chemical elements |
- |
| Name |
The value |
| Designation GOST Cyrillic |
У7АВ |
| Designation GOST Latin |
U7AB |
| Transliteration |
U7AV |
| The chemical elements |
7NW |
Description
A75 steel is used: for the manufacture of shafts, reels, winding shafts, springs and other parts of the complex form of movements and instruments, followed by heat treatment under special conditions and using different coatings and coating to prevent corrosion; details of the watch industry, subjected to subsequent thermal treatment.
Standards
| Name |
Code |
Standards |
| Sectional and shaped rolling |
В32 |
TU 14-1-1147-74, TU 14-1-2607-78, TU 14-1-3390-82, TU 14-1-505-73, TU 14-1-924-74, TU 14-130-263-94 |
Chemical composition
| Standard |
C |
S |
P |
Mn |
Cr |
Si |
Ni |
Fe |
Cu |
| TU 14-1-3390-82 |
0.7-0.8 |
0.18-0.24 |
0.04-0.08 |
0.4-0.7 |
≤0.25 |
≤0.3 |
≤0.25 |
The rest |
≤0.3 |
| TU 14-1-505-73 |
0.7-0.8 |
0.18-0.24 |
0.04-0.08 |
0.4-0.7 |
≤0.25 |
≤0.3 |
≤0.25 |
The rest |
- |
Fe is the basis.
According to TU 14-1-505-73 by agreement of the parties for special purpose hardware A75 steel should be supplied with narrowed content limits of elements without treatment with synthetic slag and purging with argon.
Mechanical characteristics
| Section, mm |
σB, MPa |
| Bars with special surface finish as supplied on the other 14-1-2607-78 |
| 1-4 |
740-980 |
| 4-6 |
690-880 |
| Bars with special surface finish as supplied on the other 14-1-3390-82 |
| 1-4 |
780-980 |
| 4-6 |
740-880 |
| 6-12 |
690-830 |
| The silverfish in the state of delivery on the other 14-1-924-74 |
| 0.4-0.95 |
736-932 |
Description mechanical marks
| Name |
Description |
| Section |
Section |
| σB |
Limit short-term strength |
Technological properties
| Name |
The value |
| Macrostructure and contamination |
The fracture of steel bars on the other 14-1-2607-78 controlled on the bars with diameter 3.0 mm and above shall be homogeneous and fine-grained. The break should be free of voids, supernote, delaminations, cracks, bubbles and inclusions visible to the naked eye. Decarbonisation on the bars is not allowed. |
| Microstructure |
The microstructure is granular pearlite silverfish on the other 14-1-924-74 should correspond to points 2-6 of the scale 2 GOST 8233. The microstructure of the steel bars on the other 14-1-2607-78 should consist of uniformly distributed fine pearlite and must comply with points 1-4 of the scale GOST 801. |
| Features of production |
Rod on the other 14-1-505-73 comes Beloretsky metallurgical plant. Bars on the other 14-1-2607-78 supplied in cold-worked condition. |
