MANDREL BAR FOR ROLLING OF HIGH ALLOY, METHOD FOR SURFACE TREATMENT OF THE MANDREL BAR, METHOD FOR MANUFACTURE OF THE MANDREL BAR, AND METHOD FOR OPERATION OF SEAMLESS STEEL PIPE PRODUCTION APPARATUS

摘要

Disclosed is a method for the surface treatment of a mandrel bar for use in the hot rolling of a high alloy steel seamless pipe, which comprises performing the scaling hot treatment of a mandrel bar and performing 50 passes or more of rolling of a common steel having a Cr content of 8% or less. In this manner, a mandrel bar for rolling a high alloy can be provided which has excellent seizure resistance and long service life.