Papers by Author: Chuan Zhen Huang

Abstract: Based on the characteristics of austenitic stainless steel 1Cr18Ni9Ti, aiming to decrease surface roughness and milling force orthogonal face milling experiment with four factors and four levels was designed to optimize machining parameters with consideration of material removal rate. Three relatively excellent machining parameters were taken to further figure out the influences of cutting speed on tool life, and the tool wear mechanism was also analyzed. The results indicated that both surface roughness and milling force were greatly influenced by cutting speed and feed. The best machining parameters obtained in the experiments were v: 200m/min, f_z: 0.1mm/z, a_p: 0.9mm, a_e: 35mm. The main tool failure mode under this circumstance was tool chipping at the flank between main cutting edge and surface to be processed, besides, the wear of rake face was relatively slight.

Abstract: The new Monte Carlo Potts model that couples with fabrication parameters and considers pores and additives has been developed in order to simulate the fabrication of single-phase ceramics tool materials. The microstructure evolution for single-phase Al₂O₃ ceramic tool materials is simulated with the different technology parameters. At the same time, the single-phase Al₂O₃ ceramic tool materials are fabricated with the corresponding technology parameters. The errors of grain size between the simulated and the experimental is 12.1 and18.2%.

Abstract: In order to improve the machining efficiency and tool life in manufacturing process of hydrogenation reactor shell components, the cutting performance of quadrate GC4235 coated carbide tool in intermittent turning 2.25Cr-1Mo-0.25V steel was investigated, the optimal cutting parameters were obtained. The empirical mathematical models of relationships among the amount of metal removal, tool life, cutting force and cutting parameters were established. The failure mechanism of the GC4235 carbide coated tools for turning 2.25Cr-1Mo-0.25V steel at lower speed intermittent turning was abrasive wear and the coating peeling; however coating peeling and substrate adhesive wear were the main failure forms at the higher speed.

Abstract: Three kinds of whisker toughened composite ceramic tools were prepared by carbothermal reduction process and their fracture performance was investigated in cutting the quenched 45 steel. The results suggest that the ratio of C to N has an effect on the fracture resistance of ceramic tool, and the whisker in tool material can inhibit the crack propagation and desquamation of grains. At the low cutting speed, the main fracture mode was conchoidal desquamation on the tool rake face and severe oxidation wear and some diffusion wear happened. At the medium cutting speed or high cutting speed, a combination of mechanical load and thermal load applied on the tool and adhesion was caused between workpiece material and tool material, and so the fracture mode was break-off of the cutting edge.

Abstract: Al2O3-TiN-TiC ceramic materials with different MgO content were fabricated by hot-pressing technique. The MgO volume percent was varied from 0vol% to 5vol%. Three point bending test was applied to get the flexural strength and the Vickers indentation was applied to get the Vickers hardness and the fracture toughness. The phase composition of the ceramics was analyzed by XRD. The effects of the content of MgO on the mechanical properties and the phase composition of Al2O3-TiN-TiC were investigated. The results shows that the addition of MgO can change the phase composition of the sintered ceramic materials which displayed with diverse solid solutions and intermetallic compounds. The convertion of the mechanical properties can also be explained by the XRD results.

Abstract: The relationship between fabrication pressure and microstructure evolution is proposed. A computer simulation coupled with fabrication pressure for the hot-pressing process of single-phase ceramic tool materials has been developed, which uses a two-dimensional hexagon lattice model mapped from the realistic microstructure without considering the presence of pores. The fabrication of single-phase Al2O3 is simulated. The mean grain size of simulated microstructure by Monte Carlo Potts model integrated with fabrication pressure increases with an increase in fabrication pressure, which is consistent with the experiment results. It is shown that Monte Carlo Potts model coupled with fabrication pressure may simulate the microstructure evolution of single-phase ceramic tool materials.

Abstract: A TiC whisker toughening Al₂O₃ composite ceramic tool material was developed by an in situ carbothermal reduction synthesis technology. The influence of different synthesis temperatures (1480°C and 1700°C) and holding times (90min, 60min and 30min) on the mechanical properties of the composite was investigated. The results showed that either the lower synthesis temperature (1480°C) or the higher synthesis temperature (1700°C) was necessary to the improvement on the fracture toughness of the composite. However, when an Al₂O₃-TiO₂ eutectic system was formed during the higher temperature synthesis process, grain coarsening of the Al₂O₃ matrix became much serious, which resulted in obvious decrease in the flexure strength of the composite. Therefore, the carbothermal reduction synthesis process should be divided into two parts including the lower temperature synthesis process for increasing the yield of the TiC whisker and the subsequent higher temperature synthesis process for increasing the carbon content in the TiC whisker, and and the lower temperature synthesis process should be held for enough time (e.g. 60min) to avoid an incomplete carbothermal reduction of TiO₂.