Metal joining and strengthening methods utilizing microstructural enhancement

摘要

A method for joining first and second metal portions includes welding together the portions such that a weld nugget joins them, compressively stressing the weld nugget throughout its volume, and heat treating the compressively stressed weld nugget to recrystallize metal therein. A method for strengthening a metal element includes imparting compressive stress within a region of the metal element, and heat treating it such that metal of the region recrystallizes with a finer grain structure than was present in the region before the step of imparting the compressive stress. A repaired metal part includes a first, original section made of metal alloy, and a second, repair section of metal alloy joined to the original section by a recrystallized metal weld having crystals within +/−3 ASTM-112 grain sizes of the size of the crystals of the original and repair sections.