EVALUATION OF ELECTRON BEAM WELDING FOR FABRICATION OF ULTRA HIGH STRENGTH STEEL ROCKET MOTOR CASES
Monthly status rept. no. 10, 1-28 Feb 61.
MASSACHUSETTS INST OF TECH CAMBRIDGE DIV OF SPONSORED RESEARCH
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Tests were performed to qualify a special test bar design for obtaining strength data on sheet or plate welds under 21 biaxial loading conditions. The specimen was a flat tensile test bar into which identical grooves were milled on both sides of the test section, opposite one another, in a direction perpendicular to that of loading. Limits were established for groove dimensions which yielded conditions of substantially plane strain. Results of biaxial tensile tests performed on electron beam welds showed strengths that were of the order of 10 higher than those determined on the same welds using conventional test specimens. As a groove in the parent material will promote the strength about 10, it was concluded the weld metal has the same biaxial strength as the parent material. Biaxial strengths of TIG welds appeared to be somewhat lower than those of electron beam welds. Failure with electron beam welds occurred frequently at a location fairly remote from the weld 14 in. away.