Development of a High Performance Vitrified Grinding Wheel using Ultrafine-Crystalline cBN Abrasive Grains

Abstract

This paper describes the development of a high-performance vitrified bonded cBN grinding wheel using a new type of ultrafine-crystalline cBN (cBN-U) abrasive grain. Surface plunge grinding experiments using a vitrified wheel made of the cBN-U grains with a mesh size of #80/100 were carried out, and the wheel's grinding performance was compared with those of cBN vitrified wheels made of representative conventional monocrystalline and polycrystalline cBN abrasive grains. This new cBN-U abrasive grain was found to possess a higher fracture strength than these conventional cBN grains. Therefore, the cBN-U wheel exhibits a higher grinding ratio and longer grinding wheel life than conventional cBN wheels.

Compressive Strength and Interface Microstructure of PCBN Grains Brazed with High-Frequency Induction Heating Method

“…The arithmetic mean value of maximum compressive load F (N) was calculated. According to the literature [7,[24][25][26], the static compressive strength r (MPa) of the grains could be determined as follows:…”

“…The modulus M with the original grains got the maximum, when the scanning speed was 0.5 mm/s, the modulus M got the minimum. According to the literature [7], the larger the Weibull modulus M is, the more stable the grain strength distribution is. Therefore, it is known that the strongest fluctuation of grain strength distribution is obtained in the case of the current magnitude of 24 A and the scanning speed of 0.5 mm/s.…”

“…Ding et al [5] have investigated the grain wear and fracture mechanism of PCBN abrasive tools during constant-force grinding of Ti-6Al-4V alloy, and they have found that the tools with the PCBN abrasive grains could maintain the sharp cutting edges by the fracture of microcrystalline CBN particles. At the same time, Ichida et al [6,7] compared the grinding behaviors of the PCBN grains and the monocrystalline CBN grains, and they pointed out that the PCBN abrasive wheel had a lower wheel wear rate and longer wheel life. On account of the potential advantages in grinding, preparation and application of PCBN superabrasive wheels is one of the most important research topics in the present grinding community.…”

Interface characteristics and fracture behavior of brazed polycrystalline CBN grains using Cu–Sn–Ti alloy

“…The arithmetic mean value P was calculated. According to the literatures [16,17], the static compressive strength s (MPa) of the grains was determined by the following relation:…”

“…Obviously, the mean compressive strength and the moduli M corresponding to the four groups of polycrystalline CBN grains appear to be dependent on the brazing temperature. According to the relevant literature [16], the larger the Weibull modulus M, the more drastic the grain strength distribution is. Therefore, it is known that the difference in Weibull modulus among the four groups of polycrystalline CBN grains indicates that the strength distribution of the original grains is the most stable, while the fluctuation of the strength distribution of the grains brazed at 900 1C is the most strong.…”