Our liners can be used in various drilling operation conditions. Double metal liner coat used in forging steel production, inner the coat of premium liners is made from forged blank. Endotheca is made of the centrifugal casting high chromium materials, and the inner sleeve reach HB285-330 after normalizing. Honing roughness can reach more than Ra0.8 after grinding. Our product has the characteristics of the wear resistance,

corrosion resistance,high precision and long service life. Our products can be fitted to all souts of conditions and circumstances.