HOT-DUCTILITY OF THE AUSTENITIC STAINLESS STEELS

Study on the hot-ductility of steels-II

Abstract

In order to study hot-ductility of austenitic stainless steels, hot twist tests of these steels were carried out. The experiments were made with 304 and 316 type stainless steels and the twist values were compared with pierceability of the materials by a Mannesmann piercer.
Further, relations between hot-ductility and gas or structure of the materials were studied by the same test.
As a result, it was found that twist curves which showed the relation between twist values and temperature had the close connection with pierceability of materials. Therefore, the twist test gave good measure of the pierceability of the materials by the Mannesmann piercer.
The hot-ductility of the austenitic stainless steel was affected by at least two factors, that is oxygen content and composition balance. The hot-ductility decreased with increase of the oxygen content. Also those steels which had γ+α phase at high temperature showed low hot-ductility at these temperatures and were proved to have poor pierceability.