Measuring the process efficiency of controlled gas metal arc welding processes

Abstract

The thermal or process efficiency in gas metal arc welding (GMAW) is a crucial input to numerical models of the process and requires the use of an accurate welding calorimeter. In this paper, the authors compare a liquid nitrogen calorimeter with an insulated box calorimeter for measuring the process efficiency of Fronius cold metal transfer, Lincoln surface tension transfer and RapidArc, Kemppi FastRoot and standard pulsed GMAW. All of the controlled dip transfer processes had a process efficiency of y85% when measured with the liquid nitrogen calorimeter. This value was slightly higher when welding in a groove and slightly lower for the RapidArc and pulsed GMAW. The efficiency measured with the insulated box calorimeter was slightly lower, but it had the advantage of a much smaller random error.

Dissimilar metal joining of stainless steel and titanium using copper as transition metal

“…where HI is the heat input, V is the voltage, I is the intensity, TS is the travel speed and η is the welding process efficiency that for a MIG process has CMT is stipulated as 0.85 [13].…”

On arc efficiency in gas tungsten arc welding

“…Accurate calorimetric measurements of η a are difficult, and unless systematic errors are accounted for this may lead to underestimate (or even overestimate) of actual values [20]. The total error in calorimetric studies depends basically on two parts; Δη a /ɳ a = Δq w /q w + Δq n /q n (5) The measuring error in the gross arc power input Δq n /q n depends on how arc current and voltage is measured and how the gross arc power is calculated.…”

Influência da Vazão e Geometria da Região de Entrada Sobre a Eficiência Térmica Medida por um Calorímetro de Fluxo Contínuo de Água

“…Na avaliação da eficiência térmica para o processo GMAW controlado em calorímetros de nitrogênio líquido e caixa isolada realizado por Pépe et al (2011), considerou-se que o calor não transferido para a peça é perdido nas formas de radiação, evaporação do metal de solda, convecção ou condução da tocha de soldagem, entre outros. Diferentes modelos para as perdas são encontrados na literatura com suas respectivas considerações e simplificações para permitir a melhor compreensão ou modelagem dos fenômenos.…”