I found your website while searching for springs. I would like to ask you a question.
When making compression springs with piano wire or hard steel wire, it seems that tempering is always performed, but how different the durability will be if the material is not tempered? Also, is there a difference in strength (durability) between a piano wire and a hard steel wire of the same diameter?
Thank you for your question, MASA!
Materials with spring strength, such as piano wire, hard steel wire, oil tempered wire, heat-treated steel strip, and stainless steel wire for springs, are subjected to low-temperature annealing (tempering) after coiling.
The purpose of this treatment is to remove the strain (residual stress) caused by coiling to some extent and to improve the mechanical properties of the material. Cold-formed springs subjected to this process improve their fatigue properties!
Regarding the difference between piano wire and hard steel wire, compared to hard steel wire, piano wire is more strictly controlled for impurities, scratches, decarburized layers, etc., and the quality level of the material is different, and the tensile strength is also different. Because of those advantages, there is a difference in durability.
If you have any other questions, please feel free to ask!
Thank you for your reply.
I have another question. When designing an original spring with popular selected spring design software, the service life estimated is about 10 million times or more, but it is impossible to get an exact service life calculation value?
Dear MASA,
The upper limit of the service life diagram used by our company is 10^7 times or more, but it seems that some manufacturers have used the diagram with higher value (10^8 times). (Manufacturers in the automobile industry in particular)
