Proposal of Evaluation Method for Weld Decay of Stainless Steel

Abstract

Weld decay in HAZ of austentic stainles steels has been evaluated with loss in weight by method of nital-fluoric acid test. But it cannot evaluate correctly, because it has the following problems.
(1) Corrosion of cross side is serious compared with surface side, therefore total loss in weight is affected with the loss on the cross side in case of improper dimentsions of test piece.
(2) Evaluation of weld decay is affected the quantity of weld decay on bottom side in spite of the same depth of that on surface side.
(3) Weld decay of welds with narrow bead is evaluated greater than that of wide bead. The goal of this experiment is to develop a new evaluation method of weld decay. Accordingly in order to solve the said problems, we tried comparison test between voltage drop method and loss in weight by nital-fluoric acid method, using test pieces made with MIG welding, underwater MIG welding and electron beam welding. Results of experiment told us that evaluation by the former was more suitable than that of the latter.