1)High-quality spring steel, wear-resistant, anti-bending. 2)After oil quenching, higher intensity, the surface clean. Oil tempered cold roll steelTensile strength: 225,000 – 255,000 PSI 15,820 – 17,929 kg / sq. cm.Hardness: 44 – 48 Rockwell “C”size: Production as needed Oil quenching spring steel wire