Research On Laser Beam Welding TC4 Titanium Alloy To Steel

Welding of dissimilar metal is often difficult, because of difference in physics, chemistry. And they are easily coming into being intermetallic compounds when they are welded together. Heat input is one of important factors affect the quality of the weld. The less heat input, the smaller thermal expansion, heat-affected zone and residual stress are. There are also less cracks. But the heat input of traditional melt welding methods is always very large, and hard to control. Thus those methodologies are hard to gain good welds. Characteristics of the laser beam welding are high power density, rapid heating and cooling, increscent depth/width ratio of weld, small heat affect zone and easily to control heat input. So the laser beam welding is a fine welding methodology for dissimilar metal welding.The welding between TC4 titanium alloy and steel is an important application in aviation industry. It is belong to dissimilar welding, but it is more than dissimilar welding. Thus we need to analysis the weldability of TC4 titanium alloy and steel.In this paper the weldability is analysed between TC4 titanium alloy and steel based on weldability of TC4 titanium alloy and steel. The result show that argon is a good protect gas and controlling heat input is necessary if the weld can be penetrated, to prevent coming into being intermetallic compounds (TiFe and TiFe₂) and enlarging of the crystal grain. Thus the strength and plastic of weld can be improved.Coming into being intermetallic compounds and enlarging of crystal grain are related to the temperature in heat-affected zone. They are also influenced by the velocity of the heating and cooling of the weld. So the simulation of the temperature field is very necessary. A heat resource model for laser beam welding between TC4 titanium alloy and steel is put forward. And the analysis formula is also given. The simulation result is close to experiment result, thus the model is correct and can be used to simulate laser beam welding dissimilar metal.In this paper stress and strain field model is established by using elasto-plasticity theory, to forecast residual stress and strain. The deforming of x-direction is very large gained by simulation of the strain field. So we can use clamping fixture to compact the specimens against deforming. In order to reduce residual stress, we may reduce the power of laser beam and increase the velocity of the welding.In this paper we use WE methodology combining with orthogonal test to optimize process. This method can reduce the times of the experiment. We also analyse the effects of processing parameter on the weld quality. It guides how to...