Effects of a stress relief heat treatment on the toughness of pressure vessel quality steels—Influence of the plate thickness

Abstract

This paper gives the results of the third phase of a research programme on the influence of post weld heat treatments on the toughness of welded joints in pressure vessel quality steels. Special attention is paid to the minimum plate thickness for which a post weld heat treatment should be recommended. In addition to the qualification tests, several large-scale tests were carried out on test plates of various thicknesses. The results indicate that, although the present code requirements are satisfactory for a C-Mn steel, they should be completely altered for an Nb-microalloyed steel, welded with a high heat input.