Abstract: This article briefly describes the application of artificial diamond in stone processing tools. Water atomized pure iron powder indicates that a large amount of diamond in the use of the tool is not abrasion and failure, but is lost in the form of shedding. The reason for diamond loss is the diamond holding force. Not enough has caused early diamond shedding. The research results show that the pre-alloyed powder method can realize the diffusion connection between the carcass and diamond, and then clarified that the use of the pre-alloyed powder method to achieve the diffusion brazing connection to diamond is an effective way to improve the performance of diamond tools. The centrifugal gas-water combined atomization is a better preparation technique; the composition of the pre-alloy powder and the hot-pressing sintering process determine the effect of the diffusion connection on the diamond.

Foreword

Since the birth of artificial diamond in 1954, diamond saw blades have been widely used in stone processing. In recent years, the number of artificial diamonds used in the stone processing industry has continued to increase, and its consumption accounts for about the total production of artificial diamonds in the country. About 90%. According to statistics at home and abroad, it is estimated that about 70% of industrial diamonds in the world are currently used for manufacturing stone processing tools, and the majority of them are diamond circular saw blades.

In the use of the diamond circular saw blade, the utilization rate of diamond is relatively low, because the diamond in the cutter head is not abrasion and failure, but a large amount is lost in the form of shedding. Traditional diamond cutter head manufacturing is to fix the diamond by the holding effect of the carcass on the diamond. When the carcass is worn to a high exposed height of the diamond, the diamond will fall off by itself. Increasing the binding force between the carcass and diamond is the most effective technical measure to avoid early diamond shedding.

The pre-alloyed powder method is an effective way to improve the bonding force between diamond and carcass. Adding chromium, titanium, vanadium, zirconium, nickel, manganese and other metals to the pre-alloyed powder can improve the wettability of the alloy to the diamond, increase the cutting edge height of the diamond, and improve the utilization rate of the diamond; on the other hand, the pre-alloyed powder The chemical composition is stable, which overcomes the factors that affect the performance of the carcass, such as the specific gravity segregation of mechanically mixed powders, the first melting and enrichment of low-melting metals, and the easily oxidized and volatile metals that are burned during the sintering process, ensuring the diamond cutter head. Stability and consistency.

1 Main characteristics of pre-alloyed powder

The carcass of an artificial diamond blade is generally composed of a skeleton component and a binder. Generally, a group of low-melting-point metals is used as a binder. Alloy powder and pre-alloy powder are excellent binders.

Pre-alloyed powder is used as the binder of diamond tool carcass. It is easy to adjust the properties of the carcass and make it more suitable for processing. At the same time, because the pre-alloy is smelted into alloy in advance and then made into powder, each powder It contains various metal elements that make up the alloy, which is much more uniform than mechanically mixing multiple single metal powders. In the process of sintering into a diamond bit, as long as the temperature rises to the melting temperature of the pre-alloy powder, the powder of the entire bonding component will melt without the failure to take into account the large melting temperature difference between different components in the binder. The temperature problem.

The main advantages of using pre-alloyed powder as a binder for diamond tool carcass are as follows.

The diamond tool made of pre-alloyed powder can improve the diamond enveloping ability of the carcass, and has better performance such as impact resistance and improve the utilization rate of diamond.

The pre-alloyed powder does not contain volatile and oxidizable elemental elements, and diamond tools made of pre-alloyed powder improve the compactness and uniformity of the carcass, thereby improving the wear state of the carcass.

Pre-alloyed powders with different properties can be selected according to the differences in the performance of the work object, which simplifies the tire batching work. The sintering temperature of the cutter head mainly depends on the melting point of the high melting point metal in the bonding metal. The melting temperature of the pre-alloy powder is low and the hot pressing temperature is low, which can avoid the thermal damage to the diamond caused by the high sintering temperature.

The melting range of the pre-alloy powder is narrow. It should be able to just wet the diamond at a certain sintering temperature and flow under the pressure. During the hot-pressing process, the pre-alloy powder reacts with the skeleton components, which is conducive to enhancing the mechanical properties of the carcass without forming a low-melt brittle phase.

Under the normal working temperature of diamond tools, the pre-alloyed powder will not be remelted or deformed, which ensures that the bonding layer can withstand the stress transmitted by the hard particles (skeleton component and diamond) in the carcass without deformation or loosening.