Welding is extensively employed as the joining technique for metals and alloys in many manufacturing industries. The
strength of weld and thereby the weld efficiency is directly related to the micro structure of weld pool and heat-affected zone (HAZ). HAZ micro structure is completely controlled by the heat transfer rate during welding. Modeling the heat transfer and thereby predicting the weld quality is a topic of great interest to both researchers and industrialist for the last few decades. The high intensity welding arc makes the system a complex interaction of thermal, magnetic, electric, and fluid flow fields. Many 2D and 3D models have been developed and presented in literature in order to simulate the thermal, mechanical, and micro structural interactions during welding process. Welding arc has been modeled by many researchers, but the micro mechanisms of arc heat transfer is still not completely explained, and many groups are trying to connect the developments in arc physics with the welding arc and resulting heat transfer mechanisms. The first developed heat transfer models were based on conduction mode, which would fail in and around the weld pool as these models were not considered the convection effect, which is a major mode of heat transfer inside the weld pool. During the last two decades, a number of research papers were published with convection heat transfer models. Many groups were working in the optimization of arc welding by doing experiments and by invoking the advantages of modeling and simulations. The micro structural modeling of HAZ and the prediction of thermal stress and distortions during welding is another broad area where the results of welding heat transfer research are applied. The welding robots and automation of welding process is the driving force behind the current welding research. Linden [1] presents a detailed review in numerical modeling of welding and the major contributions in the welding heat transfer modeling were well explained by him. This paper is concentrating only on the recent developments in this area, by listing down major papers published in the last few years.