Heat transfer during Nd: Yag pulsed laser welding and its effect on solidification structure of austenitic stainless steels |
| |
Authors: | T Zacharia S A David J M Vitek T Debroy |
| |
Affiliation: | (1) Metals and Ceranics Division, Oak Ridge National Laboratory, 37831 Oak Ridge, TN;(2) Department of Materials Science and Engineering, Pennsylvania State University, 16802 University Park, PA |
| |
Abstract: | Theoretical and experimental investigations were carried out to determine the effect of process parameters on weld metal microstructures
of austenitic stainless steels during pulsed laser welding. Laser welds made on four austenitic stainless steels at different
power levels and scanning speeds were considered. A transient heat transfer model that takes into account fluid flow in the
weld pool was employed to simulate thermal cycles and cooling rates experienced by the material under various welding conditions.
The weld metal thermal cycles and cooling rates are related to features of the solidification structure. For the conditions
investigated, the observed fusion zone structure ranged from duplex austenite (γ)+ferrite (δ) to fully austenitic or fully
ferritic. Unlike welding with a continuous wave laser, pulsed laser welding results in thermal cycling from multiple melting
and solidification cycles in the fusion zone, causing significant post-solidification solid-state transformation to occur.
There was microstructural evidence of significant recrystallization in the fusion zone structure that can be explained on
the basis of the thermal cycles. The present investigation clearly demonstrated the potential of the computational model to
provide detailed information regarding the heat transfer conditions experienced during welding. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|