Finite Element Analysis of Thermal Effects on Brazed Cold Diamond Grit

摘要

A finite element model was setup to simulate brazing "cold" diamond grit onto steel substrate. Cold diamond grit means in the brazing process, the brazing metal and the substrate were heated to brazing temperature, and then the diamond grit at room temperature was added into the brazing metal. The results showed that brazing cold diamond grit could shorten the time it spent at elevated temperature dramatically. When the diamond grit was added 55 s later after heating of the substrate and the brazing alloy, time spent above 700 A degrees C could be decreased from 86.6 to 46 s, and time spent above 1,000 A degrees C could be decreased from 37 to 4 s. The time spent above melting point of the brazing alloy was long enough for the cold diamond to be brazed onto the substrate. Residual stress in brazed diamond grit was mainly compressive. The maximum compressive stress appeared on the lowest point of the diamond and was over 700 MPa. With 100 mu m nickel coating on the diamond grit, the maximum compressive stress was lowered to 500 MPa.