A comprehensive representation of transient

A general mathematical statement is presented to describe transient weldpool development. In the formulation, axi-symmetric systems are considered and allowance is made for buoyancy, surface tension, and electromagnetic forces. An extensive set of computed results is presented describing the behavior of aluminum, steel, and titanium, thus covering a broad range of thermal conductivities. These computed results are complemented with order of magnitude estimates of key process parameters, providing an improved insight into the overall system behavior. It is shown that through these order of magnitude estimates it is possible to predict conditions under which convection is important by recourse to the Peclet number and melt velocity estimates. It is shown, furthermore, that when surface tension effects are present, as may be the case for steel, these are likely to be dominant in determining the melt velocity.