Hi, could you please tell me about the fatigue strength of SWP-B (piano wire) and SWOSC-V (oil tempered wire)?
Based on JISB2704 and various materials, it is possible to calculate the fatigue strength from the tensile strength. If the materials have the same tensile strength, the fatigue strength can be considered the same. Therefore, according to JIS, since SWP-B and SWOSC-B have the same tensile strength, I consider their fatigue strength to be the same.
On the other hand, SWOCS-V is said to be a material with excellent fatigue resistance, and because it is oil tempered, and subjected to heat treatment, I think that it is a material superior in material strength. However, how should I think about SWP-B and SWOSC-V’s fatigue strength?
Spring Beginner, thank you for your question!
SWOSC-B and SWOSC-V are listed in JIS as:
Oil tempered wire for springs (SWOSC-B)
Oil tempered wire for valve springs (SWOSC-V).
For fatigue strength, as SWOSC-V is manufactured for valve springs of internal combustion engines, its fatigue strength is superior. The difference is that the level of control of impurities and defects is high.
In terms of chemical composition, the content of “P” and “S” is low, and the depth of defects and decarburized layer are strictly controlled.
Therefore, since there are few material defects that affect fatigue strength, the probability of breakage is lower than that of SWOSC-B, and when fatigue tests are performed at the same level stress amplitude, it can be said that SC-V has better fatigue strength.
Thanks again for your question!
Please tell me the difference between silicon chrome steel oil-tempered wire for springs and silicon manganese steel oil-tempered wire for springs.
Spring Newbie, thank you for your question!
Silicon chrome steel oil-tempered wire for springs and silicon manganese steel oil-tempered wire for springs are described with the following steel types.
Silicon chrome steel oil-tempered wire for springs (SWOSC-B)
Silicon manganese steel oil-tempered wire for springs(SWOSM-A, B, C)
There are A type, B type, C type for SWOSM, the mechanical properties are the best with type A, followed by type B and type C.
In terms of chemical composition, SWOSC-B contains “Cr” to improve the toughness and the strength of steel. This is also reflected in the mechanical properties, and SWOSC-B has better tensile strength than SWOSM. From the above, it can be said that SWOSC-B can withstand higher stress than SWOSM.
What is difference between oil temper and piano wire in term of physical properties
Thank you for your question!
The strength of oil-tempered wires and piano wires varies depending on the wire diameters. However, they have almost the same tensile strength.
In addition, by adding Si, Mn, and Cr to increase toughness, oil-tempered wires’ durability is superior compared to piano wires, so it can be said that they have better fatigue strength than piano wires.
