The Effect of Repeated Weld-Repairs on the Microstructure and Texture of 304 Stainless Steel Weld

• Main Authors: Selamat Walmanto Hia, 夏沙馬
• Other Authors: Hsien-Lung Tsai
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/11194835836122423974

碩士 === 國立臺灣科技大學 === 機械工程系 === 96 === The aim of this work was to study the effect of thermal cycles related with multiple weld repairs on the changes of fracture and texture characteristics in the HAZ of the AISI 304 stainless steel weld. The first pass of welding was conducted by GTAW and remained passes were completed by SMAW. After the final pass is finished, the weld metal was removed by grinding and the same procedure lasted for five times. Increasing numbers of weld-repairs had imposed little influence on the microstructures, texture, tensile strength and impact fracture of the HAZ. Texture orientation was determined by electron back scattering diffraction (EBSD), texture orientation in HAZ of fifth weldment still the same with the first weldment. Meanwhile ΣCSL grain boundary of HAZ first weldment was 91% and ΣCSL grain boundary of HAZ fifth weldment was 84%. The solidified microstructure with preferred orientation in the fusion zone of the weld was observed. The narrow HAZ of various welds was due to the inherent low input of SMAW process. The fracture appearance of various welds predominantly showed dimpled fracture for tensile and impact fracture specimens.