... Standards: ASTM, BS, DIN, GB, JIS used mattress spring tempered spring steel wire Grade:55CrSi,60Si2Mn,65Mn Dia:6.0~16 ... 1. Marerial: we select good quality spring steel wire rod.2. Surface treatment: advanced technology of shot blasting, 100% rubbed smooth, almost ... customer’s requests to produce many kinds of strength level for spring steel wire. Mechanical property of steel wire in static level and ...