Friction welding of probes to eg boiler tubes

摘要

The probe is normally of heat-resistant steel and it has to be welded to the tube with material which is resistant to diffusion and remains ductile at high temperature. Nickel has these characteristics, and a nickel pellet is placed between the tube and the probe. The latter is rotated and pressed against the pellet until its surfaces melt, welding of probe and tube is effected and the weld itself consists almost entirely of pure nickel.