Microstructure and mechanical properties of welding zones of diamond saw blade
LUO Xi-yu1,2，XU Yan-jun2,3 ，ZHANG Guang-ning2,3 ，SHEN Xiang1,2，LIU Yi-bo2,3
1. China Iron and Steel Research Institute Group， Beijing 100081， China 2. Advanced Technology and Materials Co.， Ltd.， Beijing 100081， China 3. Beijing Gang Yan Diamond Products Company， Beijing 102200， China
Abstract：The transverse section division of welding seam， morphology， microstructure， composition and phase， hardness and bending strength of laser welding and brazing were analyzed， the samples were from butt-welded steel matrix and powders sintering segments of diamond saw blade. The cause of the laser welding pores was also stated. Results show that the fine-arrangement column grain and residual pores exist in the laser welding melting zone with the hardness varies linearly； while bi-phase structure， obvious dendritic structure and no cracks and pores exist in the brazing melting zone with low hardness. Acicular martensite appears in the laser welding heat-affected zone (HAZ) of steel side， while in the brazing， there is no HAZ caused by phase transition in the steel side. With specific proportioning system， there is also no HAZ caused by solid phase transition in the cutter head transition layer of laser welding and brazing segments， which remains powder sintering microstructure. The bending strength of laser welding and brazing seam are 1 175 MPa and 983 MPa， respectively， both higher than the overseas security strength requirements. The bending strength of laser welding has relatively large fluctuations， which is closely related to residual pores.
2016, Vol. 26 
