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The usual method of preparing specimens for through-thickness tension tests is to weld extensions (prolongations) to the plate by shielded metal-arc, electronbeam, or friction welding and to machine ASTM standard round tension specimens from these weldments. All three methods have disadvantages. Shielded metal-arc welding is time-consuming because small electrodes must be used and the sample must cool between weld passes to minimize the size of the heat-affected zone. The equipment for friction and electron-beam welding is relatively expensive. Consequently, a rapid and low-cost stud-welding method has been developed for attaching prolongations to plate coupons to produce weldments from which tension specimens up to 12.8 mm (0.505 in.) in diameter can be prepared.
A portable stud-welding gun, mounted in a drill press to ensure axial alignment, is being used for welding studs to plate to produce weldments suitable for through-thickness testing. Welds have been made successfully on A36, A588, A514, A516, A537, and A633 steel plates, and through-thickness tension specimens machined from these weldments have been tested with a stud- or weld-failure rate of less than 2 percent. A stud fabricated from AISI 8620 steel bar and quenched and tempered to a minimum hardness of 30 Rockwell C appears to be suitable for through-thickness testing of plate products having strength levels up to and including that of A514 steel. Data show that this procedure is suitable for determining through-thickness reduction-of-area values for plate of about 25.4-mm (l-in.) thickness or more.
Test results indicated that the strength level of studs does not have a significant effect on the tensile properties of the test plate (provided that the strength of the stud is greater than that of the test plate).
alloy steels, carbon steels, materials testing, plate, welding
Senior Research Engineer, U.S. Steel Corporation Research Laboratory, Monroeville, Pa.