METHOD FOR TREATING CONTINUOUS EXTENDED LENGTHS OF TUBULAR MEMBER INTERIORS

摘要

A chemical vapour deposition method is provided for case hardening a ferrous metal interior tubular surface by exposure to diffusible boron wit h or without other diffusible elements such as silicon to enhance the wear, abrasion and corrosion resistance of the surface. The pack composition used allows for borosiliconizing of the interior surface without sintering or adhering to itself and/or adhering to the surface. The pack composition comprises between about 5% and about 20% by weight of a suitable source of boron; between about 2% and about 10% by weight of silicon material; between about 2% and about 15% by weight of an activator; and the balance being a non-sintering, non-adhering filler. The pack composition is substantially free of diffusible carbon thereby minimizing carburization of the interior surface of the tubular member, and remains free-flowing after the heating and cooling steps, to permit the treatment of continuous lengths of the interior surface of the tubular member whereby the pack composition flows freely from the tubular member interior after the treatment.