Study Of Welding Deformation And Flame Straightening Of Seat Support Tube From Power Wheelchair

The study background of this thesis is according to the feedback of practice assembly from US customers, the perpendicularity of welded support tube need under controlled to resolve the issue that seat frame could not fit to the power unit base. As the tubes were welded onto the main frame, The welding parts have deformation and perpendicularity of tubes always out of tolerance because of welding residual stress, so, remedy of tube perpendicularity is normally required. Being a method to remedy deformation, flame straightening has been implemented into practice production. This thesis combine theory and practice, calculated process and result by ANSYS from welding deformation and flame straightening firstly, then proved the feasibility of this method by experiment.The model of the support tube is built in the chapter of welding deformation. After calculated by ANSYS, the Von stress has been got at nine different time after simulation of welding. The thesis further analyzed residual stress on the path which built from five spots on the model at time of 2460s, the final crooked angle of the support tube also has been got.In the chapter of flame straightening, base on the theory of flame straightening and after calculated by ANSYS, three remedy results at temperature of 600oC, 700oC and 800oC have been got. Especially at temperature of 800oC, the remedy status at five different time also have been shown. After cool the model 600s, the remedy angle and final perpendicularity angle have been got after comparison of welding deformation angel and flame straightening angle.Five main frames have been took into experiment, follow the procedure of flame straightening in the previous chapter, the perpendicularity angel of support tubes were measured, recorded and compared before and after flame straightening, and comparison of the angel values have proved the feasibility of flame straightening in the practice production.