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U.S. Department of Energy
Office of Scientific and Technical Information

Low-alloy steels for thick-walled pressure vessels. Summary report, February 1, 1980-January 31, 1982

Technical Report ·
OSTI ID:5228749

This program aimed to modify existing commercial pressure vessel steels to provide strong, tough, creep resistant materials, with low hydrogen attack and temper embrittlement susceptibilities, which can also be field-fabricated into thick-section vessels for coal conversion systems. Emphasis was placed on determining the effects of Mn, Ni and Cr on the creep rupture and hydrogen attack susceptibilities of Cr-Mo steels. Hydrogen attack studies were also carried out on A533B and model alloy systems to investigate the role of alloy carbides in promoting resistance to hydrogen damage. Creep rupture fracture times were determined at 500, 560 and 600/sup 0/C for periods up to 2000 hours. The effects of cooling rate from the austenitizing temperature and tempering response on the microstructure of 3Cr-1Mo-1Mn-1Ni steel were studied. The carbide structures in all the alloy modifications were carefully characterized. Data were collected from preliminary weld bead-on-plate tests of A387 and temper embrittlement studies of A543 with mischmetal addition. The unloading compliance test technique for J/sub Ic/ measurements was completed for A533B specimens but shortage of material prevented testing of A387. The mechanical property, elevated temperature creep and hydrogen attack data suggested that addition of 0.75 Cr + 0.5 Mn + 1Ni was beneficial in reducing susceptibility to hydrogen damage but was detrimental to creep rupture properties. 44 figures, 14 tables.

Research Organization:
Oak Ridge National Lab., TN (USA); California Univ., Berkeley (USA). Dept. of Materials Science and Mineral Engineering
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
5228749
Report Number(s):
DOE/NBM-2018324; ON: DE82018324
Country of Publication:
United States
Language:
English