Cr对镍基焊条熔敷金属静力韧度的影响

Effect of Cr on Static Toughness of Ni-Based Electrode-Deposited Metal

对合金元素有差异的两类镍基焊条实验,发现镍基焊条熔敷金属的显微组织均由γ相树枝晶组成.熔敷金属硬度在焊根和表面有差异,在焊根处硬度较大.镍基焊条熔敷金属在拉伸过程中容易发生形变诱导相变,诱导原来fcc的γ相,生成bcc组织.通过该机制,Cr含量高的熔敷金属表现出良好的塑性和静力韧度,拉伸实验中,其拉伸断口的形貌为韧窝特征,但是在低温冲击实验中,其低温冲击韧性较差.Cr含量低的熔敷金属塑性较差,拉伸实验断口形貌为韧窝和解理混合特性,其低温冲击性能优于Cr含量高的熔敷金属.

The microstructure of the metal deposited at a Ni-based electrode is composed of the dendritic gamma crystal phase.The deposited metal at the weld root is harder than that at the surface.In the process of stretching,Ni-based electrode-deposited metal is prone to deformation-induced phase transition to the gamma phase of the original fcc and the generation of bcc tissue.Via this mechanism,deposited metal with a high Cr content shows good plasticity and static toughness.In a tensile test,the tensile fracture morphology is characterized by dimples,but in a lowtemperature impact test,its low-temperature impact toughness is poor.Weld metal with a low Cr content has poor plasticity,its fracture morphology in a tensile test is characterized by dimples and dissociation mixing,and its impact property at low temperature is better than that of the deposited metal with a high Cr content.