Abstract :
The second part of the review covers mass and heat transfer in fusion welding, other than that specifically related to the arc column. Metal transfer is considered under the headings of flux-shielded and gas-shielded processes. The major portion of experimental work is concerned with the gas-shielded processes, for which a substantial amount of quantitative information is available on such matters as transfer modes, drop rates, drop temperature, the effect of shielding gas and the effect of pressure. The development of specialised power sources for the gas metal arc process is considered. Flow in the weld pool has been studied for those cases (for example, submerged arc welding) where it is mechanically induced, and for gas tungsten arc welds where electromagnetic or surface tension forces may dominate. The extensive literature on heat flow in the workpiece is briefly reviewed, and recent developments in welding process modelling are surveyed.
