大型框架结构堆焊过程的动态应力及残余应力分析

对大面积激光熔覆和MIG堆焊过程中结构动态应力演变行为进行了研究.结果表明,激光熔覆过程在结构中引起的动态应力值较小,远小于结构的屈服强度.MIG焊堆焊过程中动态应力最大值出现在立柱中部位置,最大拉应力为311.27MPa,已超过材料的屈服强度;焊后对结构宽度方向的尺寸进行了测量,比原始尺寸增加了0.4mm.用盲孔法测试了堆焊前后结构的残余应力,无论是激光熔覆还是MIG堆焊,堆焊层局部残余应力均比原始应力有较大的增加,最大应力值均在220MPa左右.

Analysis of dynamic and residual stresses in overlaying process of large frame construction

The structural dynamic stresses in the process of large area overlaying by using laser cladding and MIG welding methods were observed. The results show that the maximum dynamic stress is much lower than the yield stress of the structure in the process of laser overlaying butgreater than the yield stress in the process of MIG overlaying welding, and the maximum tensile stress which produced in the middle of the structure is 311.27 MPa.The dimension increases 0.4 mm in width after the MIG overlaying welding. The maximum residual stresses measured by hole-drilling method, after the laser overlaying welding or MIG overlayingwelding, reaches about 220 MPa both.