Assessment of tool wear in friction stir welding of high carbon steel

摘要

Limited tool longevity is one critical issue that has been inhibiting the industrialization of the friction stir welding (FSW) of structural materials. Recent advancements in both tool materials developments and tool designs have not been able to make remarkable improvements in tool life. For example, the recently developed Tungsten-25%Rhenium (by wt%) binder based poly-crystalline cubic boron nitride (pCBN) tools showed limited success in the FSW of high strength steels and nickel based super alloys, while the pCBN tools cannot be employed for the FSW of titanium alloys due to their chemical incompatibility1. Despite of all the limitations, the majority of the FSW research community has been employing tungsten carbide based alloy (WC) tools, since these are inexpensive and easily available1. Furthermore, severe tool wear and lower tool durability is also inhibiting the commercialization of the novel variants of the friction stir welding. Despite of all the limitations, majority of the FSW research community has been employing tungsten carbide based alloy (WC) tools, since these are inexpensive and easily available. However, the current knowledge on WC tool decay mechanisms and tool wear under different welding conditions is limited. Therefore, the current study focuses on the quantitative assessment of wear and decay in WC tools during the FSW of high carbon steel.