Analysis of intergranular carbide precipitate in haz of martensitic stainless steel

Analysis of intragranular carbide precipitate in the heat affected zone (haz) of martensitic stainless steel (mss) weldment was carried out. low carbon grade martensitic stainless steel weldment subjected to four point bend test in simulated sweet crude environment was analysed with transmission electron microscope (tem). the optical microscopy of the failed sample revealed the presence of intergranular cracks on both sides of the weldment in the haz. electron transparent sample for tem was prepared from the haz of the weldment using extraction replica technique. the examination of tem specimen in imaging mode revealed the presence of precipitates on grain boundaries. the compositional analysis of the precipitates was carried out with energy dispersive x-ray (edx). the result of edx analysis showed the presence of chromium and molybdenum,this suggests,the precipitates were carbides of the form m23c6. the study therefore upholds sensitisation as the mechanism behind the intergranular cracks observed in the haz of the mss weldment. © school of engineering,taylor’s university.