PeeningPeening is a procedure that involves lightly ham-mering a weld as it cools. This process aids in relievingbuilt-up stresses and preventing surface cracking in thejoint area; however, peening should be done with carebecause excess hammering can work harden and in-crease stresses in the weld. This condition leads to weldembrittlement and early failure. Some welds are cov-ered by specific codes that prohibit peening so youshould check the weld specification before peening.