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High Temperature Brittle Fracture of Austenitic Stainless Flange
Author(s) -
Van der Horst J. M. A.,
Sloan Charles R.
Publication year - 1974
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.19740050409
Subject(s) - flange , creep , materials science , intergranular corrosion , brittleness , metallurgy , brittle fracture , austenite , superheater , fracture (geology) , high heat , composite material , boiler (water heating) , alloy , microstructure , engineering , waste management
A 321 SS 16″ 400 lb. flange, located at the exit of the waste heat boiler in a reformer gas line, was subjected to high line expansions stresses. It failed in creep rupture after 4 2/3 years. An expansion joint was installed to absorb the line stresses. The new 321 flange broke in 30 days. The fracture was mostly intergranular but definitely not of the creep type. Large stringers in the matrix, associated with the forging direction, were identified as sigma phase. Since process temperature was 1135 °F and metal temperature 890 °F, the formation of sigma by process conditions within 30 days was highly unlikely. Heat treating parameters which could have caused this condition were established.