In the field of welding metallurgy, much attention is given to the effects which the welding arc or flame will have on the structure and properties of the metals being joined. The engineer is interested in the intensity and extent of physical changes brought about by the unavoidable "heat treatment" which accompanies the execution of a weld.

Since Bernandos of Russia in 1887 applied an electric arc to weld metals, welding has become an important method of fabrication in industry. The ever increasing use of welding on a still widening variety of materials demands m ore and m ore understanding of the basic mechanisms of welding.

Welding occupies an important place as a major metal fabricating process and steel is the backbone of many an industry. Therefore it is of paramount importance to know the effect of welding on steel.

Good welding research requires accurate control of the variables involved,to achieve consistent results. The variables involved in arc welding are of the dependent and independent type. Control of the independent variables such as arc current, arc voltage and welding velocity is necessary to control the independent variables such as penetration, electrode consumption rate, etc. The purpose of this thesis was to design, develop and test an automatic welding machine which controlled the above variables within the limits required for welding research.