Mechanic strength of Ti-cp submitted to Laser or TIG welding

Objectives: The purpose of this study was to evaluate the effect of TIG (tungsten inert gas) welding in the cp Ti rods using tensile and flexural strength tests, and compare this method with conventional method (Nd:YAG Laser)to make titanium welding.

Methods: Sixty cylindrical specimens were prepared (30 of each test). Three groups for each test were formed (n=10) I: control, no welding (intact specimens); II: TIG welding (Origotig 150HF, Brazil) and III: Nd:YAG laser welding (model DL 2002S, Dentaurum; Germany). Metallic specimens were obtained by the casting of cylindrical rods (diameter of 2 mm; 60 mm in length) and randomly assigned in three groups of 10 specimens. The rods were submitted to tensile and flexural strength tests in an Instron machine at a crosshead speed of 1.0 mm/min and a load cell of 500 Kg applied on the welded interface (or at the middle point of the rod non-welded specimens). The specimens were fixed in two supports separated by a 50 mm distance.

Results: The data were subjected to ANOVA (P<.05) and Tukey test. In the tensile test, there were not significant differences between the investigated weldings (p=0.015; I= 605.84> II= 514.90 = III= 515.84). In the flexural strength test there were significant differences for the groups (p=0.000; I=1908.75 > III= 1621.64 > II= 1019.32).

Conclusion: It was concluded that TIG welding may allow satisfactory and similar results to Nd:YAG Laser welding. (Supported by FAPESP grant # 06/55785-9)