论文部分内容阅读
采集金刚石圆锯片激光焊和高频钎焊部位作试样,分析研究了钢基体与粉末烧结刀头过渡层对焊焊缝横向的区段划分、焊缝形貌、金相组织、成分与物相、硬度及抗弯强度,并阐述了激光焊气孔的成因。结果表明:激光焊熔化区柱晶组织排布细腻,有残留气孔,硬度呈线性变化;钎焊熔化区为两相组织,枝晶明显,无裂纹气孔,硬度较低。激光焊钢热影响区产生针状马氏体;钎焊不存在相变引起的热影响区。激光焊和钎焊的刀头过渡层,在特定的配料体系下,也不存在固态相变引发的热影响区,基本保持了粉末烧结组织。激光焊和钎焊焊缝的抗弯强度均值分别为1 175 MPa、983 MPa,都大于国外安全强度要求,但激光焊焊缝强度波动相对较大,这与其残留气孔密切相关。
The laser welding and high frequency brazed parts of the diamond saw were collected for the test. The transverse section of the butt weld, the weld morphology, microstructure, composition and microstructure of the transition layer between the steel substrate and the sintered powder tip were analyzed. Phase, hardness and flexural strength, and describes the causes of laser welding porosity. The results show that the columnar microstructure in the laser melting zone is exquisitely arranged with residual pores and the hardness changes linearly. The brazing zone is a two - phase structure with obvious dendrites and no crack pores with low hardness. Laser-welded steel heat-affected zone produces acicular martensite; brazing does not exist heat-affected zone caused by phase change. Laser welding and brazing blade transition layer, under the specific ingredient system, there is no heat affected zone caused by solid phase transformation, the basic sintered powder sintered tissue. The mean values of flexural strength of laser welding and braze welding are 1 175 MPa and 983 MPa, respectively, which are higher than those of other countries. However, the strength of laser welding seam fluctuates relatively, which is closely related to the residual stomata.