Specification, development, and optimization of the welding and post-weld heat treatment procedures

摘要

A manual metal arc procedure was successfully developed and qualified for the Sizewell 'A' boiler repairs. The basis for this procedure was a 'temper' bead technique which allowed the creation of a fine grained HAZ in the repair weldment.A local post weld heat treatment procedure was developed in which thermal gradients were minimised and a ramp rate, close to the maximum allowable code values, was achieved. This, in combination with the fine grained repair weld HAZ, gave a high level ofconfidence that the boilers could be repaired successfully and without the reoccurrence of stress relief cracking.