ABSTRACT
Weld metals from rutile shielded metal arc welding (SMAW) electrodes usually have high contents of both oxygen and nitrogen, with nitrogen levels around 200 ppm. In SMAW the drops usually are transferred by contact between the tip of the electrode and the workpiece, while in gas-metal arc welding both bridging transfer and free-flight transfer can be found. In SMAW the drop is thought to form as a consequence of pressure from emitted vapor at the cathode spot. In SMAW, banding is observed occasionally, depending on coating type. The weld metals mainly solidify with a cellular or dendritic structure. The weld metal starts to solidify at temperatures below about 1500°C. The weld metal solidifies under conditions of constitutional supercooling. The weld metal thus transforms back to basically the same structure as in the as-deposited region, but with a different shape and size of the austenite grains.
