STP631: Fatigue-Crack Propagation in Electroslag Weldments

    Kapadia, BM
    Associate research consultant and research technician, U.S. Steel Corporation, Research Laboratory, Monroeville, Pa.

    Imhof, EJ
    Associate research consultant and research technician, U.S. Steel Corporation, Research Laboratory, Monroeville, Pa.

    Pages: 15    Published: Jan 1977


    Abstract

    The paper discusses the results of an investigation of fatigue-crack propagation behavior of as-deposited electroslag weldments in two hot-rolled structural steels, ASTM A36 and ASTM A588 Grade A. Fatigue-crack growth tests were conducted on 1T wedge-opening-loading (WOL) specimens machined from six 1-in.-thick and four 4-in.-thick weldments that were representative of electroslag welds for bridges. The testing was done in air at room temperature under tension-to-tension sinusoidal loading. Various orientations and locations of the fatigue crack in relation to the weld geometry were investigated.

    The fatigue-crack growth rates (da/dN) in the weldments were similar to, or up to five times slower than, the rate in the base steels. The retardation in crack-growth rate was most pronounced at low values of the stress-intensity factor range (ΔK) and was substantially greater for crack propagation in the coarse-grained heat-affected zone (HAZ) and bond-line regions than in the weld metal. Marked variations in the microstructure of the weld metal and HAZ had no signficant influence on crack-propagation behavior, which appeared to be influenced primarily by the residual stresses in the weldments as discussed in a separate paper.

    The results of this study show that the upper bound of the crack-growth behavior for low-strength structural steels may be used as a conservative estimate of the crack-propagation behavior of as-deposited electroslag weldments in such steels. On this basis, the prediction of the service life of electroslag-welded structures subjected to cyclic loads, and the determination of safe inspection intervals, may be made by the same approach as that presently used for standard structural-steel weldments made by other processes.

    Keywords:

    fatigue (materials), crack propagation, electroslag welding, structural steels, retarding


    Paper ID: STP35538S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP35538S


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