The Research On Forming Mechanism Of Diode Laser-TIG Arc Hybrid Surface Cladding

In order to obtain well-spread cladding layer with small contact angles,high power diode laser must be applied,which will bring other problems such as intense thermal shock,high residual stress,high cracking tendency and cladding layer diluted by base material.Using diode laser coupled with TIG arc can utilize the respective advantages of these two heat sources,obtaining cladding layers with good macroscopic morphology.However,the laser-TIG hybrid heat source is only used in deep penetration welding and its forming mechanism cannot be applied to surface cladding.The process parameters already known cannot be applied to other cladding materials or base materials,since there is a huge difference between the chemical contents and thermophysical properties of different materials.Obtaining appropriate process parameters must undergo exploration of process experiment,which will cost enormous money and time,and thereby restricting the application of Laser-TIG hybrid cladding.Recording the melting process of powder during cladding proc ess was proposed as a solution to study the forming mechanism of diode laser-TIG arc hybrid surface cladding.The melting process was fragmented to analyze the influence of different heat source parameters on hybrid heat source characteristic and macroscopic morphology of cladding layer.So that the function of different heat sourc es in hybrid cladding can be explained.A high-speed camera system aiming at recording cladding process of diode laserTIG arc hybrid surface cladding was established.With this system,the process of powder melting,gathering,fusing,spreading and formin g was recorded,and five characteristic behaviors can be concluded for a complete process.The time interval s between each characteristic behavior can be extracted to reflect the demand for heat of different periods.The contact angles of the melt were extracted to explain the spreading ability.The characteristics of sufferance force,heat distribution and heat transfer during different periods for the melt was analyzed.The deficiency of diode laser as the only heat source of cladding was explained,an d how TIG arc affected forming process with the force and heat distribution was analyzed.The forming mechanism of some typical formation was also analyzed.