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Microstructural investigation of the weld HAZ in a modified 800H alloy

Journal Article · · Journal of Engineering for Gas Turbines and Power; (United States)
DOI:https://doi.org/10.1115/1.2906866· OSTI ID:6910040
;  [1]
  1. Univ. of Tennessee, Knoxville, TN (United States). Materials Science and Engineering

Detailed metallographic investigations of Gleeble simulated HAZ samples in modified 800H were performed. Precipitate dissolution, gain growth, HAZ liquation and the hardness degradation behavior in modified 800H were also addressed. Results of this study agree with previous HAZ hot cracking and softening behavior evaluations. Modified 800H is one of the newly developed high-temperature alloys for applications in coal-fired power generating systems (Swindeman, 1991). Modified 800H possesses a greater creep and higher temperature tensile strength as compared to standard alloy 800 and conventional austenitic stainless steels. To achieve excellent creep and high-temperature tensile strength a thermomechanical treatment is applied during alloy fabrication (5--10% cold work). Therefore, grain growth, recrystallization, and precipitate dissolution and redistribution will occur in the weld HAZ during fabrication. Thus, both mechanical and metallurgical degradation may occur in the HAZ. Additionally, metallurgical reactions adjacent to the fusion boundary, including a partially melted region and constitutional liquation, may occur and influence the hot cracking resistance.

OSTI ID:
6910040
Journal Information:
Journal of Engineering for Gas Turbines and Power; (United States), Journal Name: Journal of Engineering for Gas Turbines and Power; (United States) Vol. 116:3; ISSN JETPEZ; ISSN 0742-4795
Country of Publication:
United States
Language:
English