... spring tempered spring steel wire Grade:55CrSi,60Si2Mn,65Mn Dia:6.0~16.0mm Standards: ASTM, BS, DIN, GB, JIS used mattress spring tempered spring steel wire Grade:55CrSi,60Si2Mn ... ,65Mn Dia:6.0~16.0mmStandards: ASTM, BS, DIN, GB, JISAdvantage:1. Marerial: we select good quality spring steel wire ...