PSI - Issue 13

Luka Grubiša et al. / Procedia Structural Integrity 13 (2018) 430–437 Luka Grubiša, Darko Bajić, Tomaž Vuherer / Structural Integrity Procedia 00 (2018) 000 – 000

431

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With application of plasma arc welding procedure, it is possible to weld materials with thickness up to 10 mm in a single pass. A nozzle that compresses the arc and increases the current density with in it and therefore achieves an electric arc of greater penetration. In plasma welding, insoluble tungsten electrodes are used. The application of combination of plasma and TIG welding procedure is common. The plasma arc welding procedure is used to achieve a high-quality weld joint root, while the conventional TIG procedure is used for finalizing the face of weld joint. By using an activating solder in the conventional TIG welding process, significant positive effects were achieved, and the process itself is called ATIG, according to the research Bajić (2003). If we use the same activating solder in plasma arc welding, it is expected to obtain positive effects in the welding of austenitic steels too. The procedure is called A-plasma arc welding. The paper presents an overview of the obtained results of the mechanical properties of austenitic stainless steel 316L in the A-plasma arc welding process, as a new and more advanced technique in comparison to the the conventional plasma method.

Nomenclature R p 0,2

yield strength tensile strength

R m A 5

elongation temperature

T

I

welding cureent voltage arc welding

U v q R F L W

welding speed

the flow of shielding atmospheres (argon)

radius force length width

B , δ

thickness

E

energy

Ei Ep

energy initiation energy propagation

J

J-integral

K JIC

fracture toughness

2. A-plasma arc welding

A-plasma arc welding uses an activating titanium oxide-based solder, which has a positive effect on the layout of the welding voltage. The positive influence of the activating solder on the formation of the seam metal is explained by the Marangoni effect of the fluid flow (Fig. 1) that is based on the Heat Coefficient of Surface Tension - HCST melt, according to the research Xu at al. (2007) or Tseng at al. (2011). Before the start of the welding, the activating solder is mixed with ethanol alcohol, and then applied onto the butt surfaces of the welded elements, Fig. 2.