The use of internal friction techniques as a quality control tool in the mild steel industry

Advanced sheet steels for automotive body in white applications are continually being developed to provide opportunities for fabricating lighter weight structures which achieve high standards of strength and rigidity. Interstitial free and bake hardenable steels offer significant benefits compared to traditional steel grades. However, to realise the full advantages available, it is vital that target levels of solute carbon and nitrogen levels are achieved through close control of key processing stages. The present paper describes the application of equipment developed to measure internal friction at room temperature and analysis of the interstitial content of selected production steel grades. Progress demonstrates that the accuracy and repeatability of these measurements offers the potential for the data obtained to provide the metallurgical knowledge required to enhance established methods of quality assurance.