Bi-metal hy-chrome cast-iron cylinder employs ASTM1045 forged technology. Hardness: 160BHN; Elongation rate: 17% (δ>17%). Tensile strength not less than 610Mpa; Yield stress not less than 450Mpa; it is of the dislocation prevention protection design.

Inner sleeve is made up of high chromium cast-iron forging, with thickness of 6.35~8.89mm.The bore hardness is 60 to 70 Rockwell C scales while the hull has high tensile strength of more than 7000PSI. Combining the characteristics of chrome with state of the art manufacturing, the liners can withstand mud pressure of above 7000PSI, the life of our Hy-chrome liners is proved to generally reach a level that more than 800 hours, and it can be matched and interchanged with international famous brands such as EMSCO, GARDNER-DENVER, NATIONAL, OILWELL, IDECO, WILSON, OPI, GASO, SKYTOP, BREWSTER, WIRTH. We have got the certificate of ISO9001 international quality management system and the certificate of registration of American Petroleum Institute Spec 7K.