The Effects of Weld Thermal Cycles on Additively Manufactured 316L Stainless Steel

<p>To address the size limitation of the powder bed fusion system in additive manufacturing, the welding properties of 316L stainless steel manufactured by SLM 125HL are investigated by conducting hot ductility test and nil strength temperature (NST) test with a physical thermal mechanical simulator, Gleeble. In this study, the print orientations (Zdirection and XY-direction) and the laser patterns (stripe and checker board) are studied. In NST test, the orientation showed a statistical significance in NST: Z-direction was 1384°C and XY-direction was 1400°C. In hot ductility test, all of ductility curves show similar behaviors: hardening region, recrystallization region, and liquation region. The additively manufactured 316L shows poor ductility compared to wrought 316L stainless steel. Also, there is a noticeable difference in ductility between laser pattern. Finally, ductility after the thermal cycle shows higher than that before the thermal cycle. For the future recommendation, investigation on the interelayer temperatures and sigma phase determination should be conducted to confirm the hypotheses to explain the phenomena observed in this study.</p>

Name thesis:degree_name

MS in Industrial Engineering

Discipline thesis:degree_discipline

Industrial and Manufacturing Engineering

Year dc:date.available

2019

Author dc:creator

• Yamanaka, Hajime

Contributors dc:contributor

• Xuan Wang

• Additive manufacturing
• 316L stainless steel
• Hot ductility test
• Nil strength temperature test
• Sigma phase

Identifier

10.15368/theses.2019.46

OAI identifier oai:identifier

oai:digitalcommons.calpoly.edu:theses-3448