Laser Welding Seam Predication And Shape Quality Analysis For TC4 Titannium

Titanium has excellent corrosion resistance, small density, shape memory, superelastic, high damping, high specific strength, good toughness and weldability special characteristics. It has been widely used in aviation, aerospace, petrochemical, shipbuilding, automotive, medical and other fields, as important structural material and biological materials. The study of titanium laser welding has been got more and more attention till now. But it is well known that laser welding TC4 titanium alloy is an extremely complex physical and chemical processes. At the same time, because of the special nature, structure, different structure of TC4 titanium alloy, and the different laser welding system, the welding process is full of diversity and uncertainty. Own to the shape of the seam directly affect weld quality, accurately predicting the shape of the weld seam by establishing the mapping relationship between welding parameters and the shape of seam is great useful. Programing the seam prediction of TC4 titanium alloy for laser welding software with ability of independent derivation can find suitable parameters for welding process before the beginning of weld work, in order to effectively guide the experiments, reduce costs and improve efficiency. Therefore, the work of laser weld prediction and the forming quality analysis for TC4 titanium alloy is particularly significant to our deeply understanding of deep penetration welding of titanium alloys and promoting practical applications of laser welding of titanium.Slab CO₂ laser and Fiber laser were used in scanning welding of TC4 titanium plate in thickness of 8mm for modifying mathematical model of laser deep penetration welding. Through compare analysis of results of theoretical and experimental, looked for the differences in law between them, summed up the appropriate experience formula, it can be done to optimize the laser deep penetration welding and weld seam forming and make sure the mathematical model more consistent with TC4 laser deep penetration welding process.The Visual Basic and Matlab joint programming were used as platform to exploit seam prediction software for TC4 Titanium alloy laser welding. The software successfully predicted by experimental verification of TC4 titanium alloy welding process parameters and seam forming in the study.It was be done in experment to analysis forming quality of the 5mm TC4 titanium alloy laser welding joints by the welding process parameters high-power with high-speed and low-power with low-speed with two different lasers. The results show that, tensile strength of joint is mainly affected by the quality of weld seam, and it is inversely by the biting edge sharpness.When the welding heat input is large, the seam prone to generate weld defects of over penetration in welded joints, lead to stress concentration and reduce the relative displacement of the sample. In this case, the tensile properties of the joints was decreased. In the laser welding of TC4 titanium alloy, the suitable welding parameters with small heat input should be selected in order to obtain weld joints with better mechanical properties.