Process-oriented modeling and simulation of unsteady modulated gas flows in plasma powder cladding to influence layer properties

点击翻译按钮获取中文摘要

The objective of this research project is to develop an approach to identify and characterize the effects of time-varying non-stationary modulated process gas streams on the melt reaction during plasma cladding with regards to oscillation and current. It is expected that an improvement in the mechanical properties can be achieved with a favorable distribution of hard particles and through refinement of the microstructure. Two alloys will be introduced as hard material powder to the plasma arc during this investigation. The two alloys are a stellite cobalt alloy and a stellite alloy alongside tungsten carbides. The cobalt stellite powder will be altered by the weld pool solidification process such that dendritic growth is interrupted, in order to obtain a more fine-grained deposit. The goal for the stellite with the added tungsten carbides is to achieve an even distribution of tungsten carbides throughout the weld by agitating the weld pool to counteract gravity segregation of the tungsten carbides. The results of this investigation should make it possible to have a basic understanding of transient process gas streams in a PTA hardfacing process with regards to the resulting physical effects and to develop economic uses from this knowledge. This knowledge can then be used to enhance the wear properties of this process by changing the microstructure and macrostructures of these overlays, and furthermore be used to expand upon the current application boundaries.