The fractography features of fracture of the creep tested 2,25Cr-1Mo steel in the initialstate and after the operation during 6·104 hours in the process of oil hydrocracking processwere analyzed. It was found the creep fracture occurs for the classic ductile mechanism by theway of nucleation, growth and association of pores. Special fractographic feature of degradedsteel is large and deep holes caused by decohesion nonmetallic inclusions from the matrix.The next feature is the big and plate disc-shaped dimples with the small micropores aroundcarbides on their bottom. Both types of holes were grown under the influence of hydrogenaccumulated by bulk metal during operation.
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