... , Material:55SiMov, Used for oil Drilling tools and ore drilling tools 55 SiMoVA(AISI S2) ball , this product mainly used for oil drill, drill ... as 55 SiMoVA roller and ball, this product mainly used for oil drill; and drill bits parts,stamping parts, plastic parts ... -88473667 Fax:86-574-88473666 AISI UNS T41902 steel Ball for drilling tools