Cr-Mo-V钢焊接接头塑性损伤的非线性超声评价

Nonlinear ultrasonic evaluation of plastic damage for CrMo-V steel welded joint

采用非线性超声纵波技术对汽轮机转子钢30Cr2Ni4MoV焊接接头不同程度塑性损伤试样进行了超声非线性信号的检测.结果表明,超声非线性参数随着焊接接头试样塑性应变或损伤的加剧而显著上升;对于同一加载情况下的试样,与母材和热影响区相比,焊缝中心的非线性参数变化最大.同时,利用透射电子显微镜对不同塑性应变焊缝中心微观结构进行观察,发现位错密度的增加是导致非线性参数随着塑性应变增大的主要原因.

Nonlinear ultrasonic was used to inspect different plastic damage specimens of welded joint of steam turbine steel 30Cr2Ni4 MoV. Results show that nonlinear parameter increases clearly with the plastic strain or plastic damage of specimens and the variation of nonlinear parameter of weld center is the maximum,whichis compared with the ones of the heat-affected zone and base metal under the same plastic strain condition.Moreover,it is observed that the dislocation density increases with the plastic strain in the weld center in TEM photographs,which is the primary cause to induce the increase of nonlinear parameter with the growing plastic strain.