To increase the quality and lifetime of piercing mandrels for hot steel tube manufacturing, they can be coated with a plasma welded layer which offers advantages in comparison to standard piercing mandrels with a hardened and chromed surface. Carried out tests with piercing mandrels with plasma welded overlay in a comparable application did show practically no wear under mechanical load and heat stress whereas the standard mandrels have had significant material loss on the critical diameter.

Based on these results an up to three times longer lifetime of the plasma welded piercing mandrels can be expected.