SCC 予防保全を目的とした SUS316L 鋼レーザ表面溶融処理部における高温割れ発生挙動に関する理論的検討
Theoretical Analysis of Hot Cracking Behavior in Melted Regions of Type 316L Stainless Steels by Laser Surface Melting Treatment for Maintenance to Prevent SCC
著者:
森 裕章 Hiroaki MORI 西本 和俊 Kazutoshi NISHIMOTO
発刊日:
公開日:
Brittleness temperaturerange (BTR)Hot crackingLaser surface melting treatmentTheoretical analysisType 316L stainless steel
概要
The solidification brittleness temperature range (BTR) and local strain in laser surface melted regions of Type 316L stainless steels were investigated in this study, to make clear the mechanism of solidification cracking in the region. The BTR in laser surface melted regions was estimated by the calculation of its upper and lower limits with using the dendrite growth model for Fe-Cr-Ni system and the thermo-dynamic analysis based on calculated phosphorus concentrations at dendrite boundaries in the melted regions, respectively. The local strain in the melted regions during solidification was calculated by the thermal elastic-plastic analysis with a finite element method. The BTR in laser surface melted regions was narrower with increasing the velocity. On the other hand, the increment of local strain in the melted regions during solidification was increased by the increase in the velocity. As a result of comparison between th e BTR and local strain in the melted regions, the tensile strain in the melted regions increased more than the minimum strain of the BTR in the case of higher laser traveling velocities. This result indicates that solidification cracks are prone to occur in the melted region at higher laser traveling velocities.
