HT250冷焊表面残余应力试验

利用亚激光瞬间熔冷焊机对柴油发动机缸体所用材料HT250表面缺陷进行修复，并用x射线法测定焊缝两侧表面残余应力，以此研究冷焊残余应力分布规律以及与不同工艺参数间的关系．结果表明，靠近焊缝处为拉应力，远离焊缝处为压应力：冷焊残余应力范围很小，峰值主要分布在离焊缝中心5mm的范围内，离焊缝中心20mm处，残余应力接近为零；时间参数对残余应力峰值的影响较小，而能量参数对残余应力峰值的影响较大；通过改变时间与能量参数组合，可以得到较小的残余应力峰值，满足发动机再制造零部件表面损伤的修复要求．

Experimental analysis on cold-welding surface residual stress of HT250

Cold-welding technology has been applied to the engine remanufacturing field.In this paper, the surface defect of HT250 castiron used in diesel engine cylinder was repaired with inferior-laser instantaneous melting cold-welding technology.The cold-welding residual stress was measured through the X-ray diffraction method to study the regularity of residual stress and the relationship between the residual stress and different process parameters.The results show that the stress near the weld seam is tensile and the stress away from the weld seam is compressive.The cold welding residual stress distribution is quite narrow.The peak stress mainly distributes in the range of 5mm from the weld seam center and the residual stress is close to zero in the place of 20 mm away from the weld seam center.Time parameter has little influence on the peak stress while the energy parameter''s influence is great.Through the change of time and energy, smaller residual peak stress can be obtained to meet the repair requirements for surface damage on engine remanufacturing parts.