A theory for accelerated stress corrosion cracking in arc-welded aluminum alloys and mitigation by precision additive dressing
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Date
2016-02
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Abstract
Where stress corrosion cracking (SCC) of an un-welded high-strength aluminum alloy may not occur, gas-metal arc welding of the same alloy can induce SCC in an accelerated timeframe. This was found to originate from a metallurgical weld region called the fused-overlap zone (FOZ); the corrosion (pitting) reaction that occurs within the FOZ acts as the catalyst for accelerated SCC. Each of the necessary factors for SCC (i.e. corrosive environment, tensile stress, and susceptible material) is affected by arc-welding. In a saline solution, the corrosive environment becomes more acidic because of FOZ pitting; tensile stress intensity is increased by the geometric impact of FOZ and HAZ corrosion damage; the material’s susceptibility to SCC in the HAZ is increased because of the weld thermal cycle’s effect on strengthening precipitates. With respect to joint strength, practicality of production, and corrosion resistance, it was determined that precision additive dressing (PAD) is the most viable engineering solution to mitigate accelerated SCC of these welded high-strength aluminum alloys.
Description
Engineering: 3rd Place (The Ohio State University Edward F. Hayes Graduate Research Forum)
Keywords
Stress Corrosion Cracking, Aluminum, welding, precision additive dressing, GMAW, SCC