Language
What Welding Defects Easily Occur in Hot‑Stamped Plate Nut Welding with Energy‑Storage Welder?
Sep 16,2026
Hot‑stamped plates are widely used for new‑energy and automotive structural safety parts. Energy‑storage welder welding may bring defects including nut cold‑joint detachment, thread deformation rejection, plate indentation and bulging, brittle fracture of weld spots, nut offset and unstable batch‑wise torque.
I Process Difficulties of Hot‑Stamped Plate Nut Welding
1.Quenched steel carries large internal stress; it easily becomes hard and brittle under welding heat and generates micro‑cracks.
2.Low thermal conduction speed leads to concentrated heat which cannot dissipate; local over‑heating readily burns plates and nut threads.
3.Projection‑point fusion of nuts is highly sensitive: slight energy shortage causes cold joints, while slight excess energy brings crushing deformation.
4.Plates tend to indent and bulge under heat and pressure.
II Common Welding Defects and Root Causes
1.Nut cold‑joint, insufficient torque and detachment under vibration
Main causes: insufficient pre‑pressing time, poor fitting between plate and nut with tiny gaps; low welding energy realizing only surface‑layer fusion without deep bonding; oil stains and oxide scales on plate blocking electric conduction and causing unstable welding resistance; energy attenuation of equipment in long‑time production leading to insufficient heat output.
2.Nut thread deformation, unqualified go‑no‑go gauge test
Main causes: excessive welding pressure squeezing nut and distorting thread profile; instantaneous over‑heat softens nut and holes are squeezed; improper hold‑pressure setting generating thread dislocation‑deformation under molten state.
3.Plate indentation, bulging and heat‑blackened deformation
Main causes: welding position lacks rigid support and plate collapses upon thermal softening; instantaneous concentrated heat accumulation brings high‑temperature plastic deformation; uneven pressure and over‑stress on single point pull and deform plate surface.
4.Brittle‑hard weld spots, micro‑cracks and fracture under force
Main causes: high‑hardenability high‑strength steel forms brittle microstructure upon rapid cooling after high‑temperature welding; uneven heat input and local over‑heating; welding stress cannot be released and delayed cracks emerge after cooling.
5.Nut offset, one‑sided cold‑joint and offset nugget
Main causes: large positioning gap of tooling allows nut shifting and sliding in welding; electrode mis‑alignment brings asymmetric force upon pressing; too‑fast pre‑pressing shifts projection points; uneven plate surface with local suspension generates uneven fusion.
6.Severe welding spatter and batch‑wise torque drift
Main causes: gaps are not fully compacted so that discharge arcing produces spatter; surface impurities gasify and carbonize under high temperature; electrode heat accumulation, slag adhesion and wear lead to unstable conduction and force‑bearing; energy attenuation and parameter drift of equipment in continuous production.
Wuxi Haifei Intelligent Equipment Co., Ltd. https://www.haifeiwelder.com/
Wuxi Haifei Intelligent Equipment Co., Ltd. has been focusing on the R&D and production of spot‑welding machines for 17 years. The company has obtained ISO9001 Quality Management System Certification, China Compulsory Certification (3C) and CE Certification. It is a National High‑tech Enterprise, a Specialized, Refined, Differential and Innovative Enterprise of Jiangsu Province, a Specialized, Refined, Differential and Innovative Enterprise of Wuxi, and a Gazelle Enterprise in the Southern Jiangsu National Self‑Dependent Innovation Demonstration Zone.
Should you be interested in our spot‑welding machines, please contact us: 400‑0510‑750.
Related News
Wuxi HAIFEI Intelligent Equipment Co., Ltd.
Wuxi HAIFEI Welding Equipment Co., Ltd.
Add: 28 Shuiyun Road, Yuecheng, Jiangyin, Jiangsu Province, China. (Postal Code: 214404)
Mobile: +86 18915302352
Email: wushijie@jshaifei.com