Achieving consistent high-quality deep-penetration welds is difficult, due to complex activity in the weld pool. Deep-penetration welding requires specialised techniques to push the weld pool deeper into the workpiece during the welding process.
To achieve deep penetration welding with TIG the heat from the welding arc must penetrate far into the workpiece creating a deep weld pool. Keyhole TIG, or K-TIG, involves punching a small ‘keyhole’ through the workpiece with the welding arc, thus enabling the formation of a narrow cavity during welding. This cavity allows the heat from the welding arc to be distributed deeper into the workpiece.
K-TIG mitigates the insufficient energy densities of TIG based techniques by carefully controlling the electrode tip temperature, which allows variability in the arc diameter. By varying the arc diameter, it is possible to increase the physical pressure exerted by the arc on the top of the molten weld pool. When the surface tension of the weld pool is overcome, the arc breaks through the meniscus and forms the keyhole cavity, and progresses the weld pool deeper into the material.
The Hyperpulse project focuses on developing new understandings of the physics of arc shaping, and discovering the precise set of novel control parameters required to optimise the deep-penetration weld process.