Heating apparatus for a welding operation and method therefor

A method of welding a superalloy article, the method comprising the steps of:

• establishing a pre-weld heat treatment temperature profile, a welding temperature profile, and a post-weld heat treatment temperature profile for a superalloy article;
• placing the superalloy article in an enclosure with walls that enclose the article on all sides, the enclosure having associated therewith one-way flow means for venting gases from the enclosure, means for inductively heating the article, means for sensing a temperature of the article, and means for controlling the induction heating means based on the temperature of the article and according to the pre-weld heat treatment temperature profile, the welding temperature profile, and the post-weld heat treatment temperature profile;
• establishing a nonreactive atmosphere in the enclosure by sealing the enclosure with the exception of the one-way flow means and then flowing an inert gas into the enclosure, the one-way flow means allowing venting of the inert gas from the enclosure while preventing air from entering the enclosure;
• operating the induction heating means, the sensing means and the controlling means to heat the article according to the pre-weld heat treatment temperature profile;
• without removing the article from the enclosure, operating the induction heating means, the sensing means and the controlling means to heat the article directly from the pre-weld heat treatment temperature profile to the welding temperature profile;
• welding the article while maintaining the temperature of the article according to the welding temperature profile, the welding step being performed with a welding device manipulated with gloves attached to one of the walls of the enclosure, the enclosure and the one-way flow means preventing air from being drawn into the enclosure by thermal gradients induced when the article is inductively heated while the one-way flow means allows venting of the inert gas and welding fumes from the enclosure;
• and then
• without removing the article from the enclosure, operating the induction heating means, the sensing means and the controlling means to heat the article directly from the welding temperature profile to the post-weld heat treatment temperature profile.