The Effect of Heat Source Path on Thermal Evolution during Electro-Gas Welding of Thick Steel Plates

Abstract

In recent years, the shipbuilding industry has experienced a growing demand for tighter control and higher strength requirements in thick steel plate welding. Electro-gas welding (EGW) is a high heat input welding method, widely used to improve the welding efficiency of thick plates. Modelling the EGW process of thick steel plates has been challenging due to difficulties in accurately depicting the heat source path movement. An EGW experiment on 30 mm thickness E36 steel plates was conducted in this study. A semi-ellipsoid heat source model was implemented, and its movement was mathematically expressed using linear, sinusoidal, or oscillate-stop paths. The geometry of welding joints, process variables, and steel composition are taken from industrial scale experiments. The resulting thermal evolutions across all heat source-path approaches were verified against experimental observations. Practical industrial recommendations are provided and discussed in terms of the fusion quality for E36 steel plates with a heat input of 157 kJ/cm. It was found that the oscillate-stop heat path predicts thermal profile more accurately than the sinusoidal function and linear heat path for EGW welding of 30 mm thickness and above. The linear heat path approach is recommended for E36 steel plate thickness up to 20 mm, whereas maximum thickness up to 30 mm is appropriate for sinusoidal path, and maximum thickness up to 35 mm is appropriate for oscillate-stop path in EGW welding, assuming constant heat input.

A Parameterized Leblond–Devaux Equation for Predicting Phase Evolution during Welding E36 and E36Nb Marine Steels

“…The model primarily considers carbon-diffusion-based phase transformations that occur in steel during its thermal history. The phase evolution of the thermal simulation was composed of two analysis procedures: nonlinear heat transfer instantaneous and nonlinear austenite decomposition processes [3].…”

“…In the shipbuilding and marine industries, the size of the steel structure has increased rapidly in recent years [1], and the time for welding thick steel plates can account for approximately 50% of the total construction time. To improve welding efficiency, high heat input welding methods have been widely used to weld thick steel plates for marine applications [2,3]. However, the heat-affected zone (HAZ) deteriorates under high heat input welding conditions [4].…”

Optimization of hot-wire fraction for enhance quality in GMAW

“…The shipbuilding industry faces a challenge of high heat input during welding processes, particularly with conventional methods like submerged arc welding (SAW) [1][2][3][4] and electrogas arc welding (EGW) [5][6][7]. To mitigate this issue and improve weld quality, various welding techniques and processes have been suggested, including laser beam welding (LBW) [8,9] and electron beam welding (EBW) [10,11].…”

Metallurgical Process Simulation and Optimization

“…Optimized mineral phase structures of flux film were put forward to eliminate longitudinal cracks. An electro-gas welding experiment on thickness E36 steel plates was conducted in Fu et al’s study [ 13 ]. A semi-ellipsoid heat source model was developed using linear, sinusoidal, or oscillate-stop paths.…”