Study on Structures and Carbides Changes Observed in Each Specimen Before and After Creep-Rupture Test (Study on type 321 stainless steel intended for high-temperature service such as for superheater and reheater tubes-II)

Abstract

As evident on the data given in our first report, the heat treatment before creep-rupture test of type 321 stainless steel presented some remarkable results on the creep rupture strength.
In this study carbide changes observed in specimens before and after creep-rupture test were studied by various kinds of testing methods such as high-resolution electron-diffraction and select electron-diffracttion, etc. Carbides extracted from each specimen by chemical procedures were tested by X-ray diffraction.
Carbides precipitated in all the specimens quenched from the temperature range of 1300-800°C before creep-rupture test were identified as titanium carbide and carbides of other kinds. The lattice constants of titanium carbide extracted had different values depending upon each different quenching temperature.