Welding process optimization for the inner tank of the electric water heater by numerical simulation and experimental study

Abstract

The inner tank is the core weldment of the electric water heater (EWH). During service, leakage often occurs at the welds of the inner tank due to stress concentration. Reducing the welding residual stress and deformation is crucial to improve its service life. In this paper, the welding process optimization of the inner tank was investigated by numerical simulation and experimental validation. The influence of the welding sequence and welding start location of the circumferential welds (C-Welds) on the welding residual stress and deformation have been fully analyzed. The results show that the welding sequence has little effect on decreasing the welding residual stress and deformation. The peak welding residual stress and deformation reach a minimum of 170.06 MPa and 0.897 mm when the welding start location of the C-Welds was adjusted from 180° to 270° clockwise from the longitudinal weld (L-Weld), a reduction of 15.17 % and 12.98 %, respectively. The welding start location of the C-Welds is the determining factor of welding residual stress and deformation. To verify the effectiveness of the proposed welding process, full-scale welding and pulse pressure experiments were carried out. The pulse number of the inner tank has reached over 100,000 times, which satisfies the requirements of welding quality of the enterprise. This article is valuable for guiding the service life improvement of the inner tank, which results in economic efficiency growth.