Depth Profiles of Nitrogen and Oxygen absorbed in HAZ of ZrTN802D Alloy Tube by TIG Welding in Various Atmospheres (Report 2)
Kojiro KOMURO, Teruaki MISHIMA, Satoshi KUROSAWA, Hajime TSUBOI
As a study relative to the evaluation of corrosion characteristics in high temperature water of welds of ZrTN802D alloy (Zircaloy-2) tubes, continued investigations were made on the depth profiles of nitrogen (N) and oxygen (O) absorbed in HAZ by TIG welding in various atmospheres.
A calculation was attempted to estimate N depth profiles in a portion heated to β phase temperature range in HAZ. Although the calculated depth profiles were somewhat different from those of SIMS analysis values at the portions nearer the surface, the calculated value was seen to decrease rapidly toward the value of N in base metal with increase of depth. It was also found out by additional chemical and SIMS analyses of N after surface etching of the welds that the depth of diffusion of N in HAZ was not deep under this welding condition.
O was absorbed and diffused in the region heated within a phase range in HAZ, and it was also confirmed that the diffusion depth was shallower.