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Constructional alloy steel for Arctic service

Journal Article · · Met. Eng. Q.; (United States)
OSTI ID:7143987

A 0.1C-0.6Mn-1Ni-1Cr-0.3Mo heat-treated alloy steel has been developed for use in Arctic regions in applications requiring a minimum yield strength of 65 ksi and high toughness. This new steel should be suitable for welded applications for critical bridge members, line pipe fittings, and other structural members for which a high degree of toughness is required at subzero temperatures. In a study to develop a constructional steel having a minimum yield strength of 65 ksi and having high toughness at as low as -80/sup 0/F, nine heats of steel with variation in C, Mn, Ni, Cu, Cr, V, and N were melted in the laboratory, rolled to plate, quenched, and tempered. Tests of the plates showed that a 0.1C-0.6Mn-1.0 Ni-1.0Cr-0.3Mo steel met the desired strength level and had excellent transverse Charpy V-notch (CVN) impact properties at as low as -80/sup 0/F in plate thicknesses to at least 1/sup 1///sub 2/ in. The 50 percent shear-fracture-appearance transition temperature was below-80/sup 0/F, and the energy absorption exceeded 50 ft-lb at -80/sup 0/F. An 80 ton electric-furnace heat of this composition was melted and processed to plate up to 2 in. (51 mm) thick and to 24 in. OD by 0.969 in. wall (610 by 24.6 mm) seamless pipe. Mechanical property tests of the heat-treated plate samples and pipe showed that the product met the desired strength and had excellent toughness at -80/sup 0/F. Weld underbead cracking tests showed that the steel has negligible susceptibility to hydrogen-induced cracking.

Research Organization:
U.S. Steel Corp. Research Lab., Monroeville, PA
OSTI ID:
7143987
Journal Information:
Met. Eng. Q.; (United States), Journal Name: Met. Eng. Q.; (United States) Vol. 16:3; ISSN MENQA
Country of Publication:
United States
Language:
English