Numerical Analysis on Solidification Brittleness Temperature Reange in Stainless Steel

Weld Crack Susceptibility of Duplex Stainless Steel (Report V)

Abstract

Two dimensional modelling of the cellular dendritic growth during weld solidification was applied to the prediction of Solidification Brittleness Temperature Range (BTR) of several kinds of stainless steels. The calculation of BTR was done based on the observation that the lower temperature limit of BTR corresponded to the temperature at which residual liquid enriched with impurities solidified completely. This treatment gave a good agreement between the calculated and the experimental BTR for ferritic and fully austenitic stainless steel by paying attention to mesh size in the model. Moreover, the treatment was also useful to rank harmful elements in crack susceptibility. Then the modelling was applied to the prediction of the reason why duplex stainless steel had a relatively large BTR. As the results of this calculation, it was judged that nitrogen was very harmful element. This prediction was confirmed experimentally by making the tentative deposited metals containing low nitrogen.
Therefore, the calculation proposed was considered to be very useful to predict or analyze BTR for materials which solidified as single phase.