Spring steel is a name given to a wide range of steels used in the manufacture of springs, prominently in automotive and industrial suspension applications. These steels are generally low-alloy manganese, medium-carbon steel or high-carbon steel with a very high yield strength. This allows objects made of spring steel to return to their original shape despite significant deflection or twisting. For springs that are exposed to fatigue loads, high demands are placed on surface finish and inner cleanness (limitation of amount of non-metallic inclusions).
Tinsley Bridge x Ovako
Tinsley Bridge engineers decided to develop a torsion bar with slightly wider dimensions to replace the standard steel suspension torsion bar. However, because the standard spring steel grades used in torsion bars is susceptible to inclusions and other impurities, Tinsley Bridge needed a cleaner steel that could also be heat-treated to a higher stress level. So the company turned to Ovako’s Imatra mill, which was able to produce a clean, high-strength steel modified to meet Tinsley Bridge’s specifications.
EN-standard |
Ovako |
Typical analysis |
||||||
|
|
C |
Si |
Mn |
Cr |
Mo |
Ni |
Other |
33SiMnB7-3* |
SB33S17B |
0.33 |
1.7 |
0.9 |
|
|
|
B |
38Si7 |
0.38 |
1.6 |
0.7 |
|
|
|
|
|
51CrV4 |
0.51 |
0.2 |
0.9 |
1.1 |
|
|
V |
|
52CrMoV4 |
0.52 |
0.2 |
0.9 |
1.1 |
0.2 |
|
V |
|
55Cr3 |
0.55 |
0.2 |
0.9 |
0.9 |
|
|
|
|
56Si7 |
0.56 |
1.8 |
0.8 |
|
|
|
|
|
56SiCr7 |
0.56 |
1.8 |
0.9 |
0.3 |
|
|
|
|
60Cr3 |
5740 |
0.60 |
0.2 |
0.9 |
0.8 |
|
|
|
EN-standard designation followed by “*” is not an official EN standard grade but named according to the rules in EN 10027.
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