The Influence of Copper Content on the Hot Processing Properties of Steel and its Microscopic Mechanism

This study investigates the hot deformation properties of four different copper content (1.3Cu, 2.3Cu, 3.1Cu, and 6.0Cu) steels. The relationship between copper content and machinability in steel is shown by analyzing stress–strain curves, hot processing maps, and microstructures. An appropriate amount of copper (<3.1 wt%) can effectively enhance the yield strength of steel while maintaining higher workability and has good deformation ability in the temperature range of 950 °C–1160 °C and the processing range of strain rate of 0.01s −1 –7s −1 . The 1.3Cu steel and 3.1Cu steel have a weaker solid solution strengthening effect of copper, resulting in smaller band structures during high‐temperature and high‐strain‐rate compression process, while 2.3Cu steel has a stronger solid solution strengthening effect of copper, resulting in coarser band structures. However, under high temperature and high strain rate conditions, excessive copper in 6Cu steel causes copper to melt, resulting in coarsened precipitated phases, which weakens the solid solution strengthening effect of copper. The melted copper fills and lubricates the grain boundaries, significantly reducing friction and resistance between grains, allowing them to move and rearrange freely under external stress, thereby promoting grain fusion and leading to the disappearance of band structure.