FINITE ELEMENT ANALYSIS ON RESIDUAL STRESSES IN BRAZED JOINT OF CBN SUPERABRASIVE
AND 0.45%C STEEL

DING Wenfeng  XU Jiuhua  ZHOU Laishui  FU Yucan  XIAO Bing  SU Honghua

(College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016)

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 remarkable 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 corresponding 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: CBN grain 0.45%C steel substrate Brazed joint Residual stresses Embedding depth

CLC No: TG 401

国家自然科学基金(50475040)、中国博士后科学基金(20060400282)、江苏省博士后科研计划(0602039B)和江苏省自然科学基金(BK2006723)资助项目. Received 20060718, received in revised form 20070129