海洋平台用D36钢焊接构件振动时效后的组织与性能

摘要

海洋平台的焊接结构具有尺寸大、质量大、材料强度高的特点,其残余应力消除是一项十分重要但也十分困难的工作.振动时效技术可以用于海洋平台焊接结构的残余应力消除,但目前关于振动时效对海洋平台焊接结构、焊缝内部组织和疲劳性能等方面影响的研究还很少.本文选取了D36低合金高强钢的焊接构件作为研究对象,对比研究了在振动时效前后焊接构件的内应力、疲劳性能和微观组织的变化.试验结果表明,振动时效可以显著降低焊接构件的内部残余应力,同时并不会降低其疲劳性能,甚至能提高构件疲劳性能的稳定性.焊接构件的金相组织在振动前后不会发生变化,但在透射电镜下观察可以发现,构件内部的位错增多.这些研究成果为振动时效技术在海洋平台焊接结构的应用提供了新的理论基础.%The welded structure of offshore platform is featured of large-sized, heavy and high strength steels. The relief of welding residue stress contained in the structure is particular important but to certain extent very difficult. The vibration stress relief technique can be used for relieving the residue stress of offshore platform welded structure.rnHowever, the studies on the effects to the micro-structures and fatigue properties induced by VSR are seldom seen on the articles at this moment. In the paper it is taken that D36 grade low alloy high strength steel as example, has beenstudied and compared the contained residue stresses, the fatigue properties and the change of micro-structures before and after VSR treatment. The experiments show that the VSR treatment can significantly reduce the residue stress, at the same time do not negatively affect the fatigue property and even enhance the stability of the anti-fatigue property of the structure. The micro-structure will keep as the same but under the TEM the micro dislocations become more. The research results provide new theoretical basis in the industrial application of VSR technique of offshore platform welded structures.