Advantages of pre alloyed powder as the bit matrix

If the bonding metal is made of pre-alloy, the pre-alloy powder has a single melting point; its melting point can be controlled by adjusting the composition formula proportion and choice. Pre-alloyed powder than mechanical powder mixture more uniform due alloying, so its performance also improved. In the diamond drill bit during the sintering process, as long as the temperature rose above the liquids of the pre-alloy powder as a bonding ingredient, powder melting, the sintering process of the products will be over, thus avoiding the mechanical mixture of powders in the matrix sintering. The common ingredient segregation and low melting point metal is first melted and enrichment as well as oxidation, volatilization, and other ills, which can ensure the quality of the drill bit, drill performance also be improved.

Diamond drill bit often package insert is not ideal, diamond shedding phenomenon, commonly used way to add a small amount of chromium or titanium, chromium, titanium, etc. are strong carbide forming elements in the matrix, when they are with the diamond the formation of a thin layer of Cr3C2 or TiC contact between the diamond and chromium powder, titanium powder, so that chromium, titanium powder combination of both with the diamond, but also to maintain a certain binding force with the alloy matrix, thereby enhancing the holding force of the matrix alloy diamond. However, due to the chromium powder, titanium powder in the matrix alloy itself is a loose combination, and thus adds chromium powder, titanium powder to improve the limited effect of control of the carcass on the diamond, not fundamentally solve the matrix the package insert of the alloy diamond. The most fundamental way is to solve the problem of the wetting angle between the good matrix alloy and diamond.

The particle size of metal powder is less than 200 meshes in diamond drill bit. Some metal powder is easily oxidized and dirty, such as copper, titanium powder, manganese powder. It is difficult to save for a long time, such as the preservation of titanium powder vacuum-packed. Oxidation of the metal powder sintering activity is greatly reduced, and a serious impact on the quality of performance of the drill. For pre-alloy powder due to the introduction of certain antioxidant pigment, resulting alloy overall antioxidant capacity has increased, you can solve the long preservation of the powder.

In current production of bit matrix and other diamond products, in addition to a small number of rare elements are added in the form of mechanical mixture, the vast majority use the standard pre-alloy powder. In addition to skeleton metal, one matrix formula is just matching one or two kinds of pre-alloyed bonding metal. In the production of bit matrix and other diamond products in China, almost all of them still use mechanical mixing single-powder method. It only affects the production efficiency. The more important problem is that quality of diamond products is always maintained at a low level without a breakthrough. And one of the important reasons is that there are no realizations in pre-alloying of matrix metal powder.Source:http://www.mhcmp.com