Papers by Author: Xiao Huai Xue

Abstract: Despite the advantages of the high energy density, high welding velocity and low deformation, some detrimental residual stresses were still introduced during the laser beam welding (LBW) process. The aim of this work was to study the magnitude and distribution of the residual stress in the LBW seam of the high strength automobile thin sheet. With the feature of applicable to the measurement of the residual stresses in the narrow area, the indentation strain method (ISM) was employed. By appropriate design of the biaxial strain rosette with the small size, the ISM was successfully used to measure the residual stress in the thin sheet LBW seam. Also, the finite element method (FEM) was used to calculate the residual stress. The comparison of the measured residual stresses through the ISM was made with those of the cutting relaxation method (CRM) as well as the FEM results. The ISM results showed that the highest tensile residual stress located at the seam centerline and exceeded to the 60 percent of the yield strength of the base metal.

Abstract: By means of FISICO test, the cracking susceptibility of the 6061 aluminum was investigated, the experimental results showed that it is prone to form crater crack under restraint condition comparison with that of the 3003 aluminum. So the crater fill-up technology need to be employed accordingly during the field welding. The strength, elongation percentage and hardness of the as welded joint was lowered 29.7%
40%42% respectively, the former two is recovered to 73.4% and 81.7% of the base material respectively after natural aging 30days. This indicate that the natural aging treatment can remedy part of the property loss during the welding.

Abstract: The wire for high strength and toughness TMCP steels of submerged arc welding was developed. The low carbon and micro-alloying with Ti-B system was adopted to obtain the acicular ferrite dominated deposited metals. Experimental results show that the carbon equivalent (Pcm) should be higher than 0.17, which can ensure the high strength and high toughness of the deposited metals. In the alloy system, Oxygen and Nitrogen contents, micro-alloyed elements (C, Mn) and its mixture ratio are the key factors that affect the deposited metals toughness. With increasing C, Mn content, the acicular ferrite is increased and toughness is improved. Oxygen and Nitrogen are deleterious to the toughness of deposited metals.