This The process efficiency in Seem and Arc Welding is a crucial input to Mathematical models of the process and requires the use of an accurate welding calorimeter. In this paper we compare a liquid nitrogen calorimeter with an insulated box calorimeter for measuring the process efficiency of Fronius CMT, Lincoln STT and Rapid Arc, Kemppi FastRoot and standard pulsed GMAW. All the controlled dip transfer processes had a process efficiency of around 85% when measured with the liquid nitrogen calorimeter
