How to increase the holding power of the metal powder in the cobalt bond diamond segment for diamond

Diamond circular saw blade is an important tool for stone processing today. In recent years, with the vigorous development of the stone industry, it has become the project that consumes the largest amount of synthetic diamond in China. The cobalt bond segment is one of the stable segment bond at present. How to increase the matrix holding force of the cobalt bond segment to increase the grinding ability of the segment and improve the utilization rate of diamond is of great help to the stone processing industry. So how to improve it? First of all, we must understand why the segment can cut stone.

The diamond segment is welded on the circular saw blade to cut the stone, and its working principle is to use the harder material to cut the soft material. For example, the hardness and abrasiveness of stone and bond are lower than those of diamond. Therefore, during the cutting process, the matrix bond will be quickly consumed, exposing the diamond and forming a certain height difference. During the high-speed rotation of the saw blade, the diamond will be inserted into the stone with a certain forward feed speed, so that a part of the stone chips will be peeled off and flow away with the coolant. In the end, the diamond continues to cut the stone like this, and finally a groove is cut, which is the whole process of stone cutting.



However, due to the influence of the reaction force, the diamond in the segment is constantly undergoing the process of wear, breaking and falling off. Because the diamond in the segment keeps showing different cutting states, it will eventually cause the diamond segment to maintain a certain self-sharpening, so that the stone can be processed quickly. In this process, the importance of the bond to the diamond holding force is reflected. If the diamond holding force is not enough, the diamond will fall off quickly, and it will not be able to cut. This loss of cutting ability just after the operation is called early diamond shedding. This situation will lead to a significant reduction in the cutting life and cutting efficiency of the diamond segment. So as a common material for segments, what capabilities do cobalt bond segments need to increase the segment's grip on diamond?

The increased density of the matrix bond helps to improve the diamond holding force of the segment. In a large number of tests, especially the density of the pure cobalt diamond segment can reach HRB98.5, under such hardness, the segment shows the best holding ability. With the decrease of the density of the binder, the holding force of the diamond per unit area of the segment decreases, which directly affects the holding force of the diamond in the segment, resulting in short life and low efficiency in the cutting process of the segment. The increase in the density of the segment will also improve the impact toughness of the diamond, which directly affects the impact resistance of the segment. The best way to improve the density is to increase the elements with better affinity with diamond, appropriately increase the concentration and type, and make the matrix bond in the unit area of the segment more compact. The benefits of this can not only significantly improve the holding force of the diamond, but also have a positive impact on the wear resistance of the segment and the stability of the saw blade.

Liquid phase sintering can also significantly improve the holding force of the metal bond to diamond. Because diamond is a non-metallic substance that will be obviously carbonized when sintered under high temperature conditions. So low temperature sintering is the common choice. In the case of low-temperature sintering, the metal material of the segment is not completely liquid-phased, so using a metal with a lower melting point can make the sintering process liquid-phase. Through a large number of tests, it was found that in the case of non-liquid phase, the flexural strength of the bond itself was significantly reduced due to the addition of diamond during the sintering process of the segment. In the normal cutting process, the bending strength of the segment is reduced, which leads to the continuous increase of the gap between the bond and the diamond, and even the diamond is obviously loose. Therefore, in order to improve this situation, after adding the low melting point metal Zn, it will be significantly improved, the gap between the segment and the diamond will be significantly reduced, and the diamond and the metal bond will be more closely attached. Especially for the cobalt bond segment, the holding force of liquid phase sintering is particularly improved.



Titanium plating the diamond can significantly increase the holding power of the segment. It has been found that the addition of some strong carbon compounds during sintering can form a coating on the diamond surface that is better anchored to other metal matrix binders. Gradually, the diamond is titanium-plated during the diamond stirring process by people. There are many kinds of titanium plating processes. At present, there are mainly two methods: vacuum titanium plating and brazing titanium plating. The titanium element on the diamond surface after titanium plating and other metals produce better hardness, forming a more rigid metal compound, thereby increasing the holding force of the metal bond on the diamond.

Orderly arrangement of diamonds can significantly improve the holding force of the segment. This method has made good progress so far, making the diamond better, more reasonable and more evenly distributed in each layer of the diamond segment. This not only makes the force of each diamond more uniform, but also makes the holding force of the bond to the diamond more uniform, thereby improving the holding force of the matrix bond to the diamond.

In general, increasing the holding force of the segment on the diamond is a good way to solve the performance problem of the segment. At present, these methods have been incorporated into the diamond formulation and production system, and it is believed that there will be more improvement methods in the future.