Methodology to parameterize and assess the burn-zinc technique in the resistance spot welding process

Abstract

To minimize the detrimental effects of zinc during resistance spot welding of galvanized plates, a technique known as Burn-Zinc is usually employed. However, there is not much information and studies available in the current literature about when and how to use this technique. The objective of this paper is to assess and understand this technique. To do so, a methodology to determine the ideal burn-zinc parameters as a function of the plates was proposed. This methodology was evaluated by a series of welds by systematically varying current and pressure at compatible levels for zinc burning. High-speed filming, synchronized with electrical signals, was employed to visualize and to analyse results. Once the burn-zinc parameters were defined, new welds were performed with and without the burn-zinc application. The proposed experimental procedure was shown to be efficient for checking and parametrizing the burn-zinc technique. However, there was evidence that the application of burn-zinc does not always lead to a reduction in operating time.