Evaluation of X-shaped welded joints with Co-Cr alloy under different welding parameters: analysis by micro-CT and flexural strength

Abstract

This study evaluated the mechanical strength correlated to the percentage of the total volume of weld and porosities of Co-Cr alloy joints welded with TIG technique. Thirty specimens were perpendicularly sectioned to the long-axis and rejoined by using X30-shaped joint design with TIG welding. They were divided into 3 groups (n=10): the CG1 with a 60-A depth and 90-ms pulse; the CG2 with a 60-A depth and 120-ms pulse and the CG3 with a 60-A depth and 160-ms pulse. The specimens were submitted to nondestructive tests: radiographic inspection, penetrant liquid and Micro- CT (to calculate the percentage of the total volume of welding and the porosities) and then tested with 3-point bending. The fracture surfaces were analyzed with scanning electron microscopy (SEM). The data were statistically analyzed with 1-way ANOVA and the Tukey post hoc test for all the variables which were analyzed: flexural strength, total volume of weld and porosities. Pearson correlation test was also applied (ɑ=.05). The 1-way ANOVA showed that the factors machine parameters were not significant for flexural strength values (P=.231), the total volume of weld (P=.057) and porosities (P=.057). There are no significant relationships between any pair of variables after Pearson correlation test (P >.050). This, suggesting that the three machine regulation can be an option for joining prefabricated Co-Cr rods in this kind of union.

Microscopic and Mechanical Characterization of Co-Cr Dental Alloys Joined by the TIG Welding Process

“…De Castro Silverio et al evaluated Co-Cr joints under different welding parameters. They showed that the machine parameters are only one aspect in evaluating the success of the welding technique [ 37 ]. Bock et al applied laser and TIG welding on stainless steel for orthodontic purposes and showed that the microhardness and tensile strength of TIG welds were comparable to those of laser welds [ 32 ].…”

Metal Ions Release from Welded Co—Cr Dental Alloys

“…In the TIG welding process, metal structures are joined by heating and melting by means of an arc formed between a nonconsumable electrode made of tungsten and the metal parts to be joined in a protective gas atmosphere. The shielding gas atmosphere is ensured by using argon or helium [19][20][21][22][23][24].…”