Sintered metal powder for diamond tool manufacturing

Today, the metal powders used in the manufacture of diamond tools are mixed powders - except for cobalt powder. Cobalt powder is used alone in the sintering of Jingang 4 stone tool without adding any other powder.
The composition of the mixed metal powder varies depending on the use of the diamond tool. It can be understood that the mixed metal powder required when the diamond saw blade cuts hard granite is different from the softer marble. Also, the metal powder required for honing hard steel and the dressing tool used to trim the silicon carbide grinding wheel are different.
However, it is not only the use that determines the composition of the metal mixed powder. The conditions of use of the diamond tool also affect the choice of binder composition. For example, the engine power of the drive shaft during cutting has a large impact on the tool bond composition. It is not possible here to list the metal binders required for various diamond tools.
In diamond tools, the largest consumption of sintered metal powder is the saw blade. Therefore, this article only discusses the metal bond used in saw blade production.
The most commonly used metal powders in the production of diamond saw blades are as follows: cobalt, copper, tin, iron, nickel, tungsten, tungsten carbide, chromium, bronze, rare metals (zinc, manganese, silicon, silver, titanium). There are three aspects:
1) Cutting soft stone such as marble.
2) Cutting hard stone such as granite.
3) Processing other abrasive materials such as asphalt, refractory clay, concrete, etc.
For the above three applications, the previous saw blade bond contains more or less cobalt. Previously, saw blade binders for cutting abrasive materials were mainly bronze or copper/tin based, with more or less cobalt added. In contrast to the bonding of hard materials, cobalt is more or less added with copper/tin or bronze. For granite with very high abrasiveness, a small amount of tungsten or tungsten carbide is added to the cobalt base. Cutting abrasive materials requires a very wear-resistant bond, usually containing tungsten, tungsten carbide or carbonized cast tungsten. Due to the increasing trend of the composition of tungsten carbide in the tungsten carbide/cobalt binder, the sintering temperature is also required to be higher. Therefore, adding some bronze or copper/tin alloy can control the sintering temperature of the diamond to an appropriate one. In the range.
Due to the decline in the price of diamond saw blades, the diamond tool industry began to seek suitable materials to replace expensive cobalt powder several years ago, especially the small saw blades with a diameter of 31~mm or less, which are produced by the stone factory. Iron-based or nickel-based binder. The professional saw blade manufacturer has tried hard to produce saw blades for cutting granite and abrasive materials, in order to find other metal powder instead of cobalt powder, at least to reduce the content of cobalt powder. Iron-copper or nickel-copper-iron mixed powders have been tested. In some cases, corresponding pre-alloyed powders have been tested, especially fine-grained prealloyed powders, which are ideal for lowering sintering temperatures. effect.
Research on bonding agents has evolved to date, and cobalt-free or low-cobalt binders that are superior to conventional cobalt-based binders in some aspects of cutting performance have been developed. Figure 1 shows a comparison of the wear properties of three different cobalt-containing binders and one low-cobalt binder. The saw blade has a diameter of 400 mm. The diamonds used in these four saw blades are 40/50 mesh, the diamond concentration is 22, the sawing rate is 2.8 m/min, the depth of cut is 18 turns, and the cut stone is Baltic Brown granite. The four saw blades are made under the same process conditions except for the binder. The four binders are: low cobalt binder DIABASEV18, ultrafine cobalt powder (0.8um), ultrafine cobalt powder (1.4um), and 4O0 mesh cobalt powder (4um).
It can be seen from Fig. 1 that the saw blade power consumption of the low-cobalt bond DIABASEV18 is the same as that of the other three saw blades. This test leads us to believe that the consumption of cobalt can be reduced in the future manufacture of diamond saw blades. (Hong Kong British Trade Company's contribution to Wang Qin translation Li Zhihong)
 

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