Accession Number : ADA302890

Title :   Strength and Crack Resistance Behavior of Mismatched Welded Joints.

Descriptive Note : Final rept.,

Corporate Author : NAVAL SURFACE WARFARE CENTER CARDEROCK DIV ANNAPOLIS MD METALS DEPT

Personal Author(s) : Tregoning, R. L.

PDF Url : ADA302890

Report Date : JUL 1995

Pagination or Media Count : 49

Abstract : A mismatched welded component exists when the strength of the weld material is different than the strength of the base material. This research has examined the effect of weld joint geometry and mismatch level on the strength and fracture performance of high strength steel weld components. Fracture performance was studied only for applied three-point bending loading. Eleven different welded systems were constructed with mismatch ranging between -36% to +47% and various weld joint profiles to sculpt fusion zone widths between 2 and 13 mm at the crack tip. Instrumented tensile tests were utilized to characterize weldment strength behavior while single edge notch bend J-R curve testing of short (a/W = 0.15) and deeply (a/W = 0.5) cracked specimens was conducted to measure both baseline weld metal toughness properties and determine the fracture performance of mismatched systems. The results indicate that contact strengthening in unflawed specimens occurs to a greater degree and at lower constraint in conventional undermatched weldments. Flawed undermatched performance under bending loads is highly dependent on the fusion zone width as well while the degree of mismatching is a secondary effect. As the zone width decreases, the apparent tearing resistance also decreases. The overall performance of undermatched systems, however, can still be better than overmatched systems when the inherent toughness of the overmatching weld metal consumable is poor. (MM)

Descriptors :   *NAVAL VESSELS, *CRACKING(FRACTURING), *STRENGTH(MECHANICS), *STEEL, *WELD METAL, *WELDED JOINTS, PLASTIC DEFORMATION, LOADS(FORCES), TENSILE PROPERTIES, TOUGHNESS, BENDING, FRACTURE(MECHANICS), WELDMENTS, WELDS, CRACK PROPAGATION, HIGH STRENGTH, YIELD STRENGTH, CHARPY IMPACT TESTS, TENSILE TESTERS, TEARING, BASE METAL, FUSION WELDING, ZONE MELTING.

Subject Categories : Properties of Metals and Alloys
      Fabrication Metallurgy
      Couplers, Fasteners, and Joints
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE