Method for cladding the ends of a pre-clad tubular product in preparation for threading

Abstract

A method of cladding the ends of a length of previously clad pipe with a clad of greater thickness than the clad for the balance of the length in order to allow for threading, including the steps of boring, facing and turning the end of the pipe, plating by electroless deposition the faying surfaces of a nickel-base alloy cladding cylinder, assembling the cylinder to the length of pipe, assembling a close fitting tooling mandrel on the inside of the cladding cylinders, the tooling mandrel being made of a metal possessing a higher coefficient of thermal expansion than does the pipe, placing the subassembly within a housing having an induction coil therein, evacuating the housing atmosphere and back filling with an inert gas such as argon, heating the subassembly to about 1650.degree. to 2100.degree. F., thereby melting the nickel base alloy and expanding the mandrel diameter more than the subassembly diameter to obtain necessary pressure to eliminate fit-up gaps thereby metallically bonding the cladding member to the end of the pipe by means of the mechanism of liquid interface diffusion bonding.

Dependencies are inferred from the claim text.