A study of the reinforcement technology used to improve the life of mandrel bars used in seamless tube manufacturing by mandrel mill rolling

Abstract

Various heat treatments by induction heating were applied to the material of the mandrel bars used in the manufacturing of seamless tubes by mandrel mill rolling. The influence of experimental conditions was systematically examined, both using small-sized samples and at industrial scale. Within three distinct regions, delimited by a given combination of quenching and tempering temperatures, the toughness of the material could be significantly improved. When applied to mandrel bars in mandrel mill rolling, this actually resulted in longer service lives by preventing crack propagation in the vicinity of the surface. The cost of the new treatment is also lower than that of the conventional furnace heat treatment.