Mandrel bar for high-alloy rolling, method for surface treating a mandrel bar, method for producing mandrel bar, and method for operating seamless pipe mill

摘要

A method for surface treating a mandrel bar used for hot rolling of high-alloy seamless steel pipe is provided. The method includes heat treating the mandrel bar to develop a scale, and after heat treatment, rolling ordinary steel comprising 8% or less of chromium for at least 50 passes. This achieves a mandrel bar for rolling high-alloy steel possessing both durability and superior resistance to seizure.