Papers by Author: Can Bin Luo

Abstract: The new processing technique of vacuum evaporative pattern casting (V-EPC) process was explored to fabricate the cast-iron bonded cBN grinding wheels in this paper. The influences of pouring temperature, degree of vacuum, percentage and size of the cBN grits on the microstructures, distribution and thermal damage of cBN grits in the grinding layer, as well as the surface quality of the grinding layer were investigated. The experimental results revealed that thermal damage of the cBN grits and severe damage of nodulizer occurred when the pouring temperature was around 1480°C. The optimized pouring temperature for fabricate the austenite-bainite ductile cast-iron bonded cBN grinding wheels was about 1400°C. The appropriate degree of vacuum was 0.06Mpa. Too high or too low level of degree of vacuum would result in low surface quality of the grinding layer. The uniformity of the distribution of cBN grits in the metal matrix improved with the increase of the percentage and size of the cBN grits.

Abstract: In this paper, a new type of aluminum bronze was used to substitute for the traditional tin bronze as the bonding matrix of the porous diamond wheel. Effects of hot pressing sintering temperature, the amount of Al and Fe on the mechanical properties of aluminum bronze based bond were studied by means of orthogonal test. A new kind of pore inducer with spherical shape was chosen. Effects of pore inducer size and processing parameters on the pore morphology and the mechanical properties of the porous metal bonds and diamond composites were studied. Experimental results revealed that the TRS of the new type porous aluminum bronze based bond and diamond composites increased by 119% and 258% respectively compared to the traditional porous tin bronze based bond and diamond composites. Also, stronger bonding between the metal bond and diamond grits was observed.

Abstract: The possibility of using the new processing technique of vacuum evaporative pattern casting (V-EPC) process to fabricate the Al-Si based bonded diamond grinding wheels was explored in this paper. Distribution of diamond grits in the diamond/EPS composite pattern and in the grinding layer of the cast of the grinding wheel were analyzed. Microstructures and mechanical properties of the metal bonds and diamond composites fabricated by V-EPC process were studied. It is confirmed that thermal damage of the diamond grits did not occur. Strong bonding between metal bond and diamond grits can be produced. However, the uniformity of the distribution of diamond grits in the metal matrix should be further improved. Also, further hardening on the metal bond is necessity by trying other kinds of aluminum alloys.

Abstract: Effects of some alloying additives such as Cr, Co, Ni, Mn, Al on the microstructures, resulting fracture surfaces of bronze base bonds and diamond composites as well as the bonding between the metal bonds and diamond grits were studied. Experimental results revealed that under the hot pressing conditions sufficient alloying couldn’t develop as it does in the cast bronze. The degree of segregation varied with the melting point of the alloying elements. The metal with higher melting point led to a more serious segregation. Addition of strong carbide formation elements like Cr, Co could improve the bonding between the metal bonds and diamond grits and the retension of metal bond for diamond was enhanced in a way. However the addition of Al, Mn and Ni did not bring much improvement on the bonding between the metal bonds and the diamond grits.

Abstract: In this paper, two metal-bonded diamond wheels with different porosity were fabricated. The porosity of diamond wheel without additives of pore inducers is 7% and the wheel with pore inducers is 38%. Grinding experiments with these two grinding wheels on marbles were carried out under different grinding conditions. Experimental results revealed that highly porous grinding wheel has smaller grinding forces and better self-sharpening ability than the compact grinding wheel under the same grinding conditions.