How to use CK24 to produce all kinds of titanium alloy

       1. We know that the best compound carbide for producing titanium-containing cemented carbide is CK40. But if used properly, CK24 also has its own unique advantages, but we can not generalize and use the traditional fixed ratio CK24. Should be changed to a ratio of approximately WC/TiC=70/30.



     2. In order to keep improving and improve the quality of the alloy, we believe that the production of compound carbides in two different proportions, YT5 alloy (including other titanium-containing alloys) according to WC/TiC=71/29 (that is, the traditional CK24 ratio), YT14 and YT15 are based on WC/TiC=68/32 (the total carbon content of the compound carbide is 93% of the theoretical value).



    Because YT5 alloy is generally used for gravity cutting and rough milling, it needs high impact performance, but the wear resistance and accuracy of the alloy are not very high. However, YT14 and YT15 are generally used for turning carbon steel, semi-finished and fine turning. They have high requirements for the accuracy and wear resistance of the alloy, but slightly lower requirements for the impact resistance of the alloy.



3. Theoretical basis

    1. It is confirmed from relevant foreign and domestic research data that fully saturated CK24 (the original particle size of TiO2 required to produce compound carbides is less than 2 microns), in the grinding and annealing state (with Co wet grinding for 72 hours), the amount of decomposable WC phase is greater than 2%, sintered state is 2-5% (if 29/71 is used, the WC phase will be decomposed more). Also, the Fibonacci particle size at this time is the coarsest. In addition, the size of the solid solution milled subcrystals produced under this process can reach more than 3100 angstroms, which is much larger than that of CK32 above 1500 angstroms. All of the above reasons will increase the alloy grains and increase the impact resistance and toughness, so it is beneficial to improve the performance of YT5 alloy.

    2. Since YT14 and YT15 must have higher wear resistance and precision, this requires the solid solution to precipitate as little WC phase as possible during the alloy production process, and eliminate or reduce the appearance of "ring structure", but the subcrystalline size is still Be big. Therefore, it is more appropriate to design the compound carbide as WC/TiC=68/32. Because the nominal composition of CK24 refers to the saturated solubility of WC in TiC at the alloy sintering temperature, and the temperature for producing compound carbides should be above 1750℃. At this time, the dissolution of WC in TiC is still unsaturated, so the alloy is made During the process, the WC phase is continuously decomposed, and the uniformity index of the solid solution is reduced. For this reason, we think it is necessary to use the saturation advantages of CK24 and overcome its weaknesses. Therefore, the design of compound carbides used in YT14 and YT15 is more appropriate for WC/TiC=68/32. A small part of the solid solution is left in the alloy sintering to complete, which can not only reduce the precipitation of WC phase, but also greatly reduce the appearance of "ring structure". In addition, the lattice constant and subcrystalline size of the solid solution are close to those of the saturated solid solution, while the Fischer particle size and free carbon can be reduced, and its uniformity index is also improved, which is beneficial to improve the use performance of the alloy.