... 17-22mm 4.best rice, long use life PDC coal bitIntroductionPDC bit uses PDC as main cutting components,with the excellent wear-ability ... has a useful life,high-efficiency, and good performance cost. PDC bit is mainly used for drilling soft and medium formation, it ... wear resistant si welded to the body as cutting edges.PDC bit is mainly used for geological prospecting,coal exploration,water conservancy ...