Finite Element Analysis Of Resistance Spot Welding For Low-carbon Steel

In the paper, the low-carbon steel resistance spot welding(RSW) process is investigated. Through finite element method, contact analysis and electrothermal analysis is made under the condition of two dissimilar shape electrode. Considering practical production, the fluence of electrode spheric radius on RSW nugget size and nugget deviation in the different thickness plate is analyzed, which has important significance on optimizing RSW process parameters and improving stability of weld quality, and makes a foundation for the subsequent investigation on RSW mechanism.The initial conducting area and initial contact area are determined in the pre-squeeze stage of RSW, which is the basis of electrothermal process. Based on finite element software ANSYS, the finite element model of pre-squeeze contact analysis for steel RSW is built. The contact behaviors with taper-shaped and dome-shaped eletrodes are compared. The stress and strain features in the stage are analyzed, and electrode pressure influence on pre-squeezen behavior is also simulated.According to dome-shape electrode contact analysis result, the voltage, current and temperature distribution regularities are gained by analyzing electrothermal process for steel RSW. The precise shape and size about nugget and heat-affected zone are obtained after discussing nugget forming and growing characters.Spheric radius often changes because of adhesion between electrode and workpiece when dome-shaped electrode is during using dome-shaped electrode. Effect of dome-shaped eletrode spheric diamater changing on weld quality is discussed by simulating and testing verification.Through establishing projection welding and general spot welding models for dissimilar thickness plate, projection point collapsing, nugget formation and growth process are simulated. The nugget forming time and shape character differences between projection welding and general spot welding are compared, which verifies that projection weld can avoid nugget deviation effectively in dissimilar thickness plate weld.