Table definitions
Diameter: Other wire sizes on request.
Tolerance: Ovality, i. e. the difference between the largest and smallest dimension of a cross section, is maximum half the tolerance range.
Tensile strength: Conversion from tensile strength to hardness values can be calculated in standard ISO EN 18265. The tensile strength Rm within one coil does not vary more than 50 N/mm2.
Torsions: Torsion test is carried out at ≤ 6.0 mm for assessing deformability. The fracture of the torsion test piece shall be smooth and perpendicular to the wire axis. The rupture shall show no longitudinal cracks.
For round wire
| Diameter (mm) |
Tolerance (mm) |
Tensile Strength (N/mm²) |
Torsion (I=300 mm, min. revs) |
Reduct. of area (min%) |
| 2.00 - 2.50 |
±0.020 |
2180 - 2280 |
5 |
45 |
| 2.51 - 3.20 |
±0.020 |
2130 - 2230 |
5 |
45 |
| 3.21 - 4.00 |
±0.025 |
2080 - 2180 |
4 |
45 |
| 4.01 - 5.00 |
±0.025 |
2030 - 2130 |
3 |
40 |
| 5.61 - 6.00 |
±0.035 |
1980 - 2080 |
3 |
40 |
| 6.01 - 7.00 |
±0.040 |
1910 - 2010 |
|
35 |
| 7.01 - 8.00 |
±0.045 |
1860 - 1960 |
|
35 |
| 8.01 - 9.00 |
±0.045 |
1860 - 1960 |
|
35 |
| 9.01 - 10.00 |
±0.050 |
1860 - 1960 |
|
35 |
| Element |
Weight % |
| C |
0.50% - 0.70% |
| Si |
1.80% - 2.20% |
| Mn |
0.30% - 0.60% |
| P max. |
0.020% |
| S max. |
0.025% |
| Cr |
0.80% - 1.00% |
| V |
0.05% - 0.15% |
| Mo |
0.05% - 0.15 |
Cleanliness in steel
The presence of non-metallic inclusions in the wire rod is inspected for every heat of OTEVA® 91 SC in accordance with the Suzuki Garphyttan method by the steel supplier.
Before release for production, Suzuki Garphyttan performs non-metallic inclusion inspection for every fifth heat. The criteria for supplier inspection and releasing inspection are the following;
For wire rod samples: Inclusion size max. 15 µm down to 1 mm below surface. Inspection area: 1 000 mm2.
| Inclusion size, surface |
5-10 µm |
>10-15 µm |
>15 µm |
| Max. number of inclusions |
50 |
7 |
0 |
For OTEVA 91 SC PLUS, every heat is inspected including a SEM-EDS analysis of inclusions > 10µm to verify a Super Clean composition.
As stated by IVSWMA, International Valve Spring Wire Manufacturers Association, it is likely to find occasional inclusions in valve spring quality steel of a size larger than 30 µm
Surface condition – non-destructive testing
In the standard size range 2.00 - 6.00 mm the wire is tested continuously in Eddy Current equipment to a surface level of ≥ 40 microns. For size range 6.01-8.60 mm is tested continuously in Eddy Current equipment to a surface level of ≥ 60 microns. Other wire sizes on request.
Surface condition – end sample test
The wire is end sample tested by means of etch testing and binocular inspection as well as microscopical inspection of the material structure.
Max. permissible depth of partial surface decarburiza-tion and surface defects, 1 % x wire diameter. In shaved condition; for diameters <=2 .00 mm 10 µm, for diameters > 2.00 mm 0.5% x d. For diameters > 6.60-10.00 mm 0.7% x d.
