当前位置：Widetop > W1 > Widetop > Cobalt steel, used for making twist drill bits Cobalt steel, used for making twist drill bits 作者：WIDETOP • 2019-06-28 Cobalt steelA heat-resistant steel that produces increased drill bits life 上一篇文章 : Chisel-edge angle of the twist drill bits 下一篇文章 : drill diameter of the twist drill bits