| Stainless steel is widely used in urban rail vehicles,enabling the vehicle to have the advantages of high strength,corrosion resistance,long life and visual effect.However,all kinds of stainless steel welding methods that have been applied to engineering now have short performance and defects which cannot be overcome.Stainless steel end bracket structure is widely used in stainless steel thick plate material(4mm,8mm).Therefore,welding deformation,cracks and tissue defects are particularly prominent.To solve this problem,a new type of stainless steel welding mode laser-MAG hybrid welding is put forward for welding the typical joints of the stainless steel bottom chassis of the urban rail vehicle,so as to solve the welding quality problem of thick plate stainless steel.Laser-MAG hybrid welding combines two kinds of physical characteristics of energy,and makes full use of the two energy advantages while making up for their shortcomings,so as to achieve the purpose of improving welding quality of thick plate stainless steel.In this paper,three kinds of stainless steel plates,which are widely used in the bottom bracket of urban rail vehicles,are taken as test materials,and the laser-MAG composite welding tests are carried out according to the typical welded joints in the product structure.Study on the effect of welding gas flow,laser power,welding speed,defocusing distance,laser incident angle of five stainless steel laser-MAG hybrid welding parameters on the microstructure and mechanical properties through metallographic observation,hardness test,bending test,static tensile test and impact test of welded joints,and laser-MAG hybrid welding to provide theoretical support for urban rail vehicle chassis welding stainless steel end. |
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