I was studying the allowable stress of the flat springs and it led me to your website.
Basically, in the case of flat springs, I thought that the allowable stress would be the elastic limit (spring limit value), but according to the technical information on this website, in the case of static load, the allowable stress of the flat springs is 75% of tensile strength. I also checked the physical property values in JIS, but at 75% of the tensile strength, the yield strength also exceeds, and I think that it will exceed the elastic limit.
Could you tell us your opinion on this?
Thank you for writing to us, Kei!
75% tensile strength is quoted from the JSMA (established by the Japan Spring Manufacture Association), SC005 Thin Leaf Spring Design Manual. Most of the general steel materials for springs (including coil materials) have standardized tensile strength, so it seems that this is the standard.
