Stud Welding of Prolongations to Plate for Through-Thickness Tension Test Specimens

Abstract

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).