Papers by Keyword: Diamond Grit

Abstract: In this study, vacuum brazing of diamond grit was performed using an Ni-10Sn-28Cr alloy in order to examine the interfacial behaviors. In order to study the wettability between diamond grit and the brazing alloy, a graphite was used instead of diamond grit. The contact angle of Ni-10Sn-28Cr alloy and graphite decreased with increasing holding time and temperature. The shear strength between graphite and Ni-10Sn-28Cr filler alloy showed the best value of 29.8 MPa at 1100°C brazing temperature. It was shown that the shear strength was decreased significantly due to the increase of the thickness of brittle reaction layer and interface residual stress, as the brazing temperature increased up to 1200°C. In regards to the thermal stability evaluation of diamond grits, the graphitization of diamond grit was observed to occur at 1300°C brazing temperature after 60 minutes. Beyond 1100°C brazing temperature, diamond grit exhibited ideal setting in the brazing filler alloy, whereas process diamond grit was observed to be fully embedded in the brazing alloy and damaged at 1200°C temperature. The results of interface analysis of the diamond grit joints brazed by the brazing alloy showed that the chromium carbides played an important role in high strength bonding and as the brazing temperature increased, existing angular chromium carbide transformed into acicular chromium carbide.

Abstract: The wear resistance samples of brazed single crystal diamond with Ni-Cr filler alloy were prepared, using high frequency induction brazing and vacuum brazing methods. By wear test of brazed single crystal diamond, the wear performance of the samples with different brazing processes was studied. The test result indicates that the wear performance of the high frequency induction brazed diamond samples is better than that of the vacuum brazed diamond samples. Because of different brazing processes, the wearing pattern of diamond varied; the wear course of the vacuum brazed diamond samples in the initial wear period were abnormal and the failure modes is different.

Abstract: Grinding forces, protrusion and wear of diamond grit have been studied in grinding granite with a single-layer brazed diamond wheel. The experiment results indicate that the primary wear progression of diamond grits in the whole grinding process follows the mode of whole, micro-fractured, macro-fractured and pull-out when grinding granite with the brazed diamond wheel. The proportions of the whole, fractured, pull-out, break flat and the mean height protrusion of grains are more closely related to grinding forces. The grinding forces decreased with the increasing proportions of whole and break flat grains, and the tangential and normal force components increased with the gradual wear of the brazed diamond wheel during a long-time grinding process.

Abstract: Diamond grits synthesized under ultrahigh pressure have been commercially manufactured since 1957. Most of the diamond grits are for sawing rocks (granite, marble) and concrete. In 2004, more than 4 billion carats (800 tons) of diamond saw grits were produced worldwide. About 3/4 of total production was made in China, but the Chinese diamond grits tend to be smaller in size (<40 mesh) and with inferior quality, so their total value accounts for only 1/4 of the world sales (about $600 millions). The ultrahigh pressure process for synthesizing diamond grits is due to make a quantum leap: the raw materials will incorporate diamond seeds with a predetermined pattern. The result is doubling the diamond yield with a narrower size distribution. Moreover, the shape of diamond crystals can be precisely tuned. For example, diamond octahedra or diamond cubes, that are not available today, can be mass-produced. The new technology is now being implemented worldwide so the future diamond grits will have improved quality at reduced prices.

Abstract: Metal-bonded diamond impregnated tools are being increasingly used in the processing of natural stone, sawing and drilling concrete and brickwork, road repair, petroleum exploration, production of ceramics, cutting frozen foods, etc. Although the main tool wear mechanisms seem to be well identified, the scientific background is still inadequate and extensive fundamental research has to be carried out to better understand how the tool performs in actual applications. This work attempts to address the complex issues of modelling the abrasive wear of the metallic matrix under laboratory conditions. In view of the generated wear data, it becomes evident that a comprehensive characterisation of the matrix’s susceptibility to wear by 2-body and 3-body abrasion can be reliably assessed in a quick and inexpensive manner; whereas tests carried out on diamond impregnated specimens may assist in the prediction of the tool life in abrasive applications.

Abstract: The methods of making diamond tools have undergone a fantastic development since the invention of the synthetic diamond in the mid-1950’s. Over time, new production techniques based on diamond tooling have been implemented into various areas of industrial activity enabling to do the job faster, more accurately and at less cost. The recent statistics indicate that the consumption of diamond abrasives reached an impressive volume of billion carats in 2000, as compared with 380 million carats in 1990 and 100 million carats in 1980. In the new millennium the market for diamond tools continues to grow rapidly. The present decline in the price of industrial diamond makes it a commoditised product capable of competing with conventional abrasives. In terms of production volume, by far the largest group of diamond tools comprises the metal-bonded diamond impregnated tools, such as circular and frame sawblades, wire saws, and core drills for cutting natural stone and construction materials, and core bits for drilling in various rock formations. The objective of this article is to provide a compendious coverage of the PM diamond tool-making routes, and to identify the recent trends towards changing the tool design and composition to render it cheaper and more efficient.