<i>β</i>-manganese-type Phase Precipitated in High Chromium-High Nickel Austenitic Steels Containing Nitrogen

Abstract

Recently one of the present a u thors (R.T. ) has made an extensive investigation on the creep-ru pture strength of a series of high chromium-h igh ni ckel austenitic steels containing a large amount of nitrogen up to 0.7 wt % without a su bstantial amount of carbon, and established that nitrogen is a very effective a lloyi ng element to strengthen the austeni tic steels even at elevated temperatures .I ) Therefore, it is necessary to study in detail the high temperature stabi lity of th e matrix as we ll as of phases precipitated in th e high chrom ium-high nickel austenitic steels containing nitrogen .In spite of the importance of this kind of study, only a very li mited attention has been paid unti l quite recently.During the course of a metallographi c stud y of a seri es of 25 % Cr-28 % Ni a ustenitic steels containing molybd enum and /or tungsten as we ll as n itrogen, th e present authors have found a n interme tallic phase wi th th c structu re of p-manganese as a precipitated phase . 2 ) Interm etall ic phases with th e structure of p-