Embrittlement of brazed martensitic stainless steel

Abstract

Brazing of AISI 410 martensitic stainless steel (12%Cr ) with boron containing nickel based filler metal was observed to lead to two major embrittlement effects – temper embrittlement and brazement embrittlement. Temper embrittlement, resulting from slow cooling of the material after brazing, affects both the dimple rupture and final brittle fracture portions of the impact energy of the. material. Brazement embrittlement, resulting largely from the fine intra- and intergranular boride precipitates in the base metal adjacent to the braze, significantly limits the extent of dimple rupture before the onset of brittle fracture of the material under impact conditions. A simple analysis is presented which shows that the dimple rupture portion E_d and the brittle fracture portion Eb of the impact energy are affected differently by theabove embrittlement mechanisms. Their order of significance is as follows: <disp-formula><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="splitsection13-m1.tif"/></disp-formula>, where the double prime and single prime indicate the energy associated with brazement and temper embrittlement, respectively. When both embrittlement effects occur simultaneously, brazement embrittlement has a greater effect than temper embrittlement in ∆E_d estimation.