Environment assisted cracking of AISI 1020 carbon steel and iron-manganese-aluminum alloy in coal gasification environment

An increased demand of efficient and clean fuel for energy industry has led to a long term research on advanced coal gasification technology which can offer greater flexibility than existing technologies. Basic to the development of this technology is the use of available materials in coal gasification plant constructions. Such gas components as CO;AISI 1020 carbon steel was found to be susceptible to the environment assisted cracking in the aqueous coal gasification environment. The material degradation is mainly controlled by the hydrogen embrittlement. The elongation of AISI 1020 steel decreased when the specimen was pre-conditioned by immersion, especially under static loading during immersion. The CO;Environment assisted cracking of Fe-Mn-Al alloy was also observed, and the failure mechanism was found to be mainly stress corrosion cracking. The failure mode is overload ductile fracture after pre-condition immersion.;The crack growth behavior of AISI 1020 carbon steel was investigated in the aqueous coal gas environment. It is found that crack propagated faster in the coal gas environment than that in the ionic solution itself. The Back Face Strain (BFS) technique was also found efficient for measuring crack propagation of material in coal gasification environment. (Abstract shortened by UMI.).