For metallurgists, heat treatment is typically thought to be a well-understood practice. As a common process, it is used in both industrial and academic settings to change aspects of final components such as the metallic structure, stress state, and the sizes and compositions of precipitates. Because heat treatment is commonly-used, it is quite intriguing when engineers stumble upon something new or surprising about this process.
Recently, Professor of Materials Science and Engineering Chris Pistorius and his research group found that heat treatment can be leveraged to control inclusions in stainless steel. In addition to an intentional change in the metallic structure, the group found that heat treatment also creates an unintentional, substantial change in the oxide inclusions.
It is known that oxide inclusions affect how readily stainless steel can be polished. An attractive surface finish is often the reason why stainless steel is chosen, so anything that might change the polishing response should be studied carefully.