关键词: 45钢基体, CBN磨粒, 包埋深度, 残余应力, 钎焊接头

Abstract: For avoiding the grain microcrack and the joint rupture in the cooling stage during high temperature brazing, the residual stresses in the brazed joint of cubic boron nitride (CBN) superabrasive grain and 0.45%C steel with Ag-Cu-Ti alloy as filler metal is simulated by finite element method (FEM) according to the elastic-plastic theory. The results show that, several special zones, such as the center axis, the radius of the middle plane, and the radius of the section plane between the grain and the filler alloy, are the ones that have the most re-markable diversification of the residual stresses in the inner part of the brazed grain. Moreover, the margin of the section plane always endures the maximum tensile stresses. The correspond-ing experimental result indicates that the measured stresses are in accordance with the predicted ones. Based on the maximum tensile stress in the brazed grain, in order to ensure the grain strength and the storage space for chips, the embedding depth of the grains in the filler alloy is feasible to be controlled at 30%~ 40% of the whole grain crystal.

Key words: 0.45%C steel substrate, Brazed joint, CBN grain, Embedding depth, Residual stresses