2026-03-09
Short-cycle stud welding is widely adopted in thin sheet joining scenarios such as automotive components and home appliance enclosures due to its high welding speed and low heat input. However, when welding 0.7mm thin galvanized sheets, cold welding defects of studs—characterized by incomplete weld fusion and insufficient bonding strength—are prone to occur. These defects not only compromise structural integrity but may also lead to subsequent assembly loosening and seal failure. Combining the characteristics of galvanized sheets and the process principle of short-cycle welding, this paper analyzes the causes of cold welding and proposes targeted solutions for the automotive manufacturing industry. I. Core Causes of Cold Welding: Galvanized Coating Interference & Heat Input Imbalance Short-cycle stud welding achieves metallurgical bonding between studs and base metals through instantaneous arc heating, rapid cooling, and precise heat input control. Yet the properties of the galvanized coating on 0.7mm sheets (melting point at 419℃, boiling point at 907℃, far lower than steel’s 1538℃) and the high thermal conductivity of thin sheets undermine welding stability in two key aspects: 1.Galvanized coating heat absorption and volatilization interference: Under arc heating, the galvanized coating melts and volatilizes prior to the steel sheet, generating zinc vapor. Without proper coating removal or parameter setting, zinc vapor blocks direct contact between the arc and steel sheet, leading to insufficient molten pool temperature and incomplete fusion—i.e., cold welding. Meanwhile, zinc vapor is likely to cause spatter, damaging molten pool continuity. 2.Heat input imbalance: The high thermal conductivity of 0.7mm thin sheets means excessive welding current or extended welding time can easily cause burn-through, while insufficient current or overly short time results in inadequate melting of studs and steel sheets, failing to form an effective fusion layer. Both scenarios trigger cold welding. II. Systematic Solutions: Precise Control of Pretreatment, Parameters and Processes To…
