High temperature deformation of oxide scale

Samples of ultra low carbon steel were oxidized in a chamber designed to control the thickness of the scale layer prior to their deformation by plane strain compression. The specimens were reheated within the temperature range of 950–1150 °C for different periods of time to vary the scale thickness; compression was conducted at temperatures that vary from 650 to 1150 °C. Metallographic analyses were conducted on deformed and undeformed scales to evaluate the integrity of the oxide crust that is made almost exclusively of wustite. It was found that the integrity of the crust depends on the temperature at which deformation is carried out and on the amount of deformation imparted. It is concluded that thin scales exhibit a plastic behaviour when deformed at temperatures above 900 °C and a brittle behaviour at temperatures below 700 °C; mixed behaviour was observed within this temperature range, as the scale was found to resist limited amounts of deformation.