Numerical Simulation of Multilayer Hardfacing on Low Carbon Steel

In this paper, finite element analysis of manual metal arc multilayer hardfacing of low carbon steel plate using low heat input tubular chromium-carbide based electrodes is presented. The finite element analysis of residual stresses in multilayer hardfacing of low carbon steel plate is performed using ANSYS software. This analysis includes a finite element model for the thermal and mechanical analysis simulation. It also includes a moving heat source, material deposit, temperature dependent material properties, transient heat transfer and mechanical analysis. The welding simulation was considered as a sequential coupled thermo-mechanical analysis and the element birth and death technique was employed for the simulation of hardfacing metal deposition. The Von-Mises residual stress distribution and the stress magnitude in the axial direction were obtained. The simulation helped identify the correct welding parameters like welding current, welding voltage, welding speed, and base metal preheat temperature requirements, facilitating crack-free tubular hardfacing and limiting the welding residual stress. The absence of welding cracks was verified by actual hardfacing trials. Base metal pre-heating temperature of 200 degree C is required for base metal thickness greater than or equal to 15 mm, when depositing one, two or three hardfacing layers of 4 mm thickness each, to lower the weld cooling rate and to prevent cracking. Also, a time gap of 2 to 2.5 hours between the welding of each layer is required to allow the weld metal to cool before the welding of the next layer. Pre-heating and a time gap of 2 hours between the welding of each layer is also required when depositing a third hardfacing layer on mild steel plate < 15 mm thickness.