CORROSION AND CARBURIZATION BEHAVIOR OF Fe- AND Ni-BASE ALLOYS IN S-CO_2 ENVIRONMENT AT TWO TEMPERATURES

摘要

The microstructure and tensile properties of the diffusion-bonded joints of several astenitic stainless steels and Ni-base alloys were evaluated. The DB joints of austenitic stainless steels showed comparable properties to the base materials, especially for SS 347H. However, they showed failure at the DB joints when exposed to high temperature S-CO_2 environment. Meanwhile, DB joints of Ni-base alloys showed drop in tensile elongation at high temperature, even after post-bond heat treatment. Nonetheless, DB joints of Ni-base alloys were less affected when exposed to high temperature S-CO_2 environment. Considering that Ni-base alloys showed much better S-CO_2 corrosion resistance, the optimized DB conditions for Ni-base alloys should be developed for application to manufacturing of compact-type heat exchangers.