Tribological behaviour of DIN 1.2740 hot working tool steel during mandrel mill stretching process

This study evaluates the tribological properties of DIN 1.2740 hot tool steel against Super Cr13 martensitic stainless steel at 700 degrees C. The results show that the coefficient of friction (COF) ranged from 0.15 to 0.63, indicating moderate frictional interaction. The wear rate of DIN 1.2740 was observed to be low, suggesting good resistance to wear at high temperatures. The complex surface oxide layer that formed on the pin's top surface, significantly reducing the COF and acting as a solid lubricant at elevated temperatures. The oxide layer was also fragile and unable to withstand the high sliding velocities and high loads. The steel exhibited a high surface roughness when subjected to increasing normal loads and increasing sliding velocities.