The Research On Technology And Properties Of Laser-TIG Arc Hybird Heat Source Surface Cladding

The demand for surface cladding methods required by high value-added components such as oil pump, mine prop, nuclear valve and aerial engine blade have been increasingly strict. These components, with unique properties, are used in harsh working condition,requiring high quality and performance. In order to acquire these properties and metallurgical bond between the cladding layer and the substrate, heat sources applied in overlaying welding such as laser, plasma arc and TIG arc are mainly employed. However, the regulation range of single heat source is small, resulting in low cladding efficiency, high dilution ratio and obvious crack tendency. Aiming at solving this problem, an innovative cladding method using hybrid heat sources(large rectangular flare semiconductor laser and TIG arc) was proposed.In this article, firstly, a laser-TIG arc hybrid heat sources cladding experiment system was set up to conduct single and hybrid heat sources single-pass cladding experiment on Q235 steel deposited by Ni60 A alloy powder using preset powder method. The laser-TIG arc hybrid heat sources properties have been studied and the influence of process parameters such as laser power, scanning speed, defocusing amount and TIG current on formation characteristic parameters such as macroscopic morphology, cladding width, cladding height,depth-width ratio, dilution and infiltration angle has also been analyzed.Secondly, the morphology characteristics of single pass cladding layer cross section have been classified into six models according to different heat sources applied and morphology characteristics. Analyzation of different heat sources, melting process of substrate and powder,and relation between heat diffusion and forming characteristics revealed the formation mechanism of the six models. By comparing results obtained by different heat sources, it can be found that by using laser- TIG arc hybrid heat sources, the process window of ideal cladding layer can be expanded.Finally, the relation between parameters of cladding method by different heat sources and microscopic quality has been acquired by using test instruments such as SEM, XRD, EDS and microhardness tester. The best process parameters of single pass cladding were obtained by combining the relation between process parameters, microscopic performance and macroscopic morphology. By optimizing overlapping method and process parameters, single layer multi-pass cladding layer with sound performance can be obtained. This method has found practical engineering application.