Simulation of Sintering Process – Effects of Contraction Force by Particle Shrinkage and Melted Particle Volume on Growth of Void and Crack –

Abstract

The particle and the air motions in the nearly full scale sintering bed have been simulated to elucidate the void (crack) formation mechanism and the crack growth mechanism. The simulation results showed that the contraction force produced the large scale cracks in the wide area in the fixation zone above the melting zone. Since the contraction force acts toward the particle center from each contact point, the resultant force in the inhomogeneous configuration of contact point moves the particles in the melted liquid. This migration produced the agglomerate which grew continuously. The bed weight in the sintering particle bed disrupted the large agglomerate. Through the process the cracks (voids) further grew and merged to a large scale crack. Large scale cracks developed taking account of the contraction force well represented the measured large scale cracks in the full scale sintering bed obtained using CT scan. In the case that the liquid volume produced by melting was large such as 88% of particle volume, the distance between the neighboring particles in the melted liquid became large and the liquid film between particles became thick. Thus it became hard for particle to move by the resistance force in the liquid. Therefore the agglomerate and the void did not grow to the large scale crack. The agglomeration of particles for 88% of particle volume melted was not so fast that the sintering bed in which the agglomerate particles uniformly distributed was formed.