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Numerical Simulation on Nugget Formation and Evolution in Spot Welding of Aluminum Alloy*(PDF)

Transactions of Tianjin University[ISSN:1006-4982/CN:12-1248/T]

Issue:
2011年01期
Page:
28-32
Publishing date:

Info

Title:
Numerical Simulation on Nugget Formation and Evolution in Spot Welding of Aluminum Alloy*
Author(s):
CHENG Fangjie 1 2ZHANG Jianyou 1HU Shengsun 1 2 SHAN Ping 1
1. School of Material Science and Engineering, Tianjin University, Tianjin 300072, China; 2. Tianjin Key Lab of Advanced Welding and Joining, Tianjin 300072, China
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DOI:

Abstract:
With the squeeze of electrode tips, the oxide film on aluminum (Al) alloy surface is broken and numbers of micro-gaps are formed randomly. The micro-gaps act as conducting spots at the beginning of welding, so the con- tact resistance is extremely high and unstable in spot welding of Al alloy. In this paper, a new contact resistance model is adopted to simulate the nugget forming process. This model describes the random distribution characteristic of con- ducting spots. The simulation results indicate that, within the first 5 ms of welding current (AC, 50 Hz), the tempera- ture distribution at the workpieces interface is seriously irregular. In addition, the nugget does not nucleate from the weld center and grow continuously, however, it nucleates randomly from several points almost instantaneously and then merges into an entity quickly. Experimental results agreed with the numerical simulation.

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Last Update: 2011-04-07