Arc welding

About: Arc welding is a research topic. Over the lifetime, 25393 publications have been published within this topic receiving 168182 citations.

Effective heat input in pulsed current gas metal arc welding with solid wire electrodes

Abstract: In this work, the heat input of the welding arc, calculated from the measured values for voltage and current, is compared to the heat gained by the weldment for pulsed and nonpulsed current welding. The effects of shielding gas composition, arc length, weld geometry and weld position on heat transfer are examined. Methods for calculating the heat received by the weld during pulsed current welding are discussed

Welding system provided with wire feed and arc control

Abstract: In the process of arc welding with electrode wire feed there are many parameters which influence the quality of the welded joint. The welding system proposed provides considerable quality improvement, particularly in short-circuiting arc welding, reduces the dependence of the welding process upon the skill of the welder and greatly simplifies setting of the apparatus. A characteristic regulating parameter of the welding process is regulated so that the mean arc power remains substantially constant. Embodiments given by way of example illustrate ways of measuring and controlling the mean arc power, which, according to the insight on which the invention is based, is the factor which determines quality.

Finite element analysis of residual stress in the welded zone of a high strength steel

Abstract: The distribution of the residual stress in the weld joint of HQ130 grade high strength steel was investigated by means of finite element method (FEM) using ANSYS software. Welding was carried out using gas shielded arc welding with a heat input of 16 kJ/cm. The FEM analysis on the weld joint reveals that there is a stress gradient around the fusion zone of weld joint. The instantaneous residual stress on the weld surface goes up to 800 ∼ 1000 MPa and it is 500 ∼ 600 MPa, below the weld. The stress gradient near the fusion zone is higher than any other location in the surrounding area. This is attributed as one of the significant reasons for the development of cold cracks at the fusion zone in the high strength steel. In order to avoid such welding cracks, the thermal stress in the weld joint has to be minimized by controlling the weld heat input.

Research on weld pool control of welding robot with computer vision

Abstract: Purpose – The control of weld penetration in gas tungsten arc welding (GTAW) is required for a “teach and playback” robot to overcome the gap variation in the welding process. This paper aims to investigate this subject.Design/methodology/approach – This paper presents a robotic system based on the real‐time vision measurement. The primary objective has been to demonstrate the feasibility of using vision‐based image processing to measure the seam gap in real‐time and adjust welding current and wire‐feed rate to realize the penetration control during the robot‐welding process.Findings – The paper finds that vision‐based measurement of the seam gap can be used in the welding robot, in real‐time, to control weld penetration. It helps the “teach and playback” robot to adjust the welding procedures according to the gap variation.Research limitations/implications – The system requires that the seam edges can be accurately identified using a correlation method.Practical implications – The system is applicable to...

Generalized stress intensity factors due to steady and transient thermal loads with applications to welded joints

Abstract: This paper deals with the elastic and plastic stress fields induced by thermal loads in the vicinity of sharp V-notch tips in plates. Under the hypothesis of steady-state heat transfer and plane-strain conditions, the thermal and mechanical problem requires the numerical solution of an ordinary differential equation (ODE) system, obtained by extending the ‘stress function approach’. The intensity of the stress distributions ahead of V-notch tips can be expressed in terms of thermal notch stress intensity factors (thermal NSIFs), as for external loads. The problem becomes much more demanding in the presence of transient thermal loads. The residual asymptotic stress distribution arising from the solidification of a fusion zone during an arc welding process is obtained by considering different boundary conditions. An aluminium butt-welded joint is analysed after having modelled the weld toe region as a sharp V-notch. A finite element (FE) simulation of the welding process is carried out by means of SYSWELD code (version 2004.1) modelling the arc welding torch by means of Goldak's source. Near the weld toe, the intensity of the residual stress field is given in terms of elastic or elastic—plastic generalized NSIFs.