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Welding Process for T2 Pure Copper & Alloy Copper with Medium-Frequency Spot Welders
Aug 14,2026
T2 pure copper and alloy copper spot welding is widely required for new energy connectors, electrical terminals, conductive bars and switch contacts. Common defects include cold joints, spot detachment, sparks, blackened welds and brittle fracture. T2 copper and alloy copper differ drastically in thermal conductivity and hardness, requiring separate welding logic. T2 copper dissipates heat fast and struggles to form nuggets; alloy copper retains heat easily and tends to burn through.
I Welding Property Distinction
1.T2 Pure Copper: Ultra-high thermal conductivity disperses welding heat rapidly, making stable nuggets hard to form and causing cold joints. Soft texture deforms and pits easily under slight pressure.
2.Alloy Copper: Poor heat retention, accumulates heat quickly when electrified, with high brittleness at high temperature. Slightly overloaded parameters trigger splashing, black spots and microcracks; sheets burn and fracture readily.
II General Welding Strategies
1.T2 Pure Copper: High instantaneous current, ultra-short welding time to complete fusion before heat escapes.
2.Alloy Copper: Staged preheating, gradual temperature rise and post-weld slow cooling to avoid overheating-induced cracking & spattering.
III Welding Parameters for T2 Pure Copper
1 Current: Adopt instantaneous heavy current for fast fusion. Low current with long duration only disperses heat and forms invalid weak joints.
2 Pressure: Moderate stable compression. Insufficient pressure causes poor contact and arcing; excessive pressure creates deep indentations. Apply full pre-compression to fit copper surfaces tightly.
3 Electrodes: Prefer composite electrodes with good heat accumulation. Smooth, rounded electrode tips to avoid copper adhesion and rough weld surfaces.
4 Timing & Cooling: Full pre-pressure → short fusion → moderate holding forming. Fast cooling acceptable; no lengthy slow cooling needed, focus on dense nuggets.
IV Welding Parameters for Alloy Copper
1 Current: Segmented power supply – low current preheating to stabilize resistance & remove oxides, followed by steady fusion to prevent violent sparks.
2 Pressure: Moderate constant compression. Alloy copper is hard & brittle; high pressure creates internal microcracks. Maintain even contact pressure.
3 Surface Prep: Remove grease, dust, oxides and alloy impurities before welding to stabilize resistance and eliminate slag/spatter.
4 Timing & Cooling: Extended preheating, slower heat-up, prolonged post-weld pressure holding & slow cooling to release thermal stress and avoid brittle weld cracks.
V Key Points for Dissimilar Copper Welding
T2 copper loses heat quickly while alloy copper accumulates heat, leading to insufficient fusion on the copper side and over-burning on alloy contacts. Adopt four-stage process: sufficient pre-compression → low-current preheating for stable resistance → steady main fusion → pressure-held slow cooling. Balanced heat input eliminates unilateral cold joints or burn-through, reduces nugget offset, spatter and electrode adhesion.
VI Common Defect Troubleshooting
1 T2 copper cold joints & low tensile strength: Insufficient current, excessive welding time, poor surface contact.
2 Sunken, deep pits on T2 welds: Overhigh pressure & heat, extended welding duration.
3 Alloy copper spattering & black welds: Rapid temperature rise, excessive peak current, dirty surfaces, inadequate cooling.
4 Brittle fractured alloy spots: Excessive heat input, rapid cooling, concentrated stress.
5 Copper adhesion on electrodes, rough welds: Uneven electrode surfaces, overheating, poor water cooling.
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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