Papers by Keyword: Cemented Carbide Tools

Abstract: As the main-stream of the machining coating, nitrogen-based coatings have irreplaceable advantages, such as high hardness, high strength, and good oxidation resistance recently. This paper introduces common multiple nitrogen-based coatings which including TiAlN, CrAlN, TiAlSiN, CrAlSiN and CrTiAlN coatings for cemented carbide tools. The microstructure and property of coating is depended on its chemical composition. Generally, compounds of different structures are formed between the various elements of the coating, and these have different forms of existence and properties: titanium and chromium exist in nitrides (face-centered cubic structure), aluminium solubilizes in TiN/CrN, and amorphous Si₃N₄ can make difference in fine grain strengthening. The Al₂O₃ and SiO₂ can improve oxidation resistance.

Abstract: The Ti (C, N)/Al₂O₃ composite coating was prepared on surface of YT15 cemented carbide by using electro-spark deposition process. The surface morphology, energy spectrum analysis and microhardness of the coating were investigated, and the cutting forces and wear resistance of the tools with and without Ti (C, N)/Al₂O₃ composite coating were studied by cutting tests. The results show that the microhardness of the YT15 cemented carbide with Ti (C, N)/Al₂O₃ composite coating increased 181Hv, and the coating tools had better wear resistance and lower cutting force.

Abstract: This paper presents investigations on turning TC4 alloy with PVD TiAlN coated cemented carbide inserts. The turning test was conducted with variable cutting speeds ranging from 80 to 120 m/min. Wear surfaces of the cutting tools are analyzed to study the wear mechanism of PVD TiAlN coated cemented carbide tools in turning of titanium alloy TC4. Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer( EDS) analyses by wear maps indicated that the wear of coated cemented carbide tools was caused by adhesion, coating delamination and mechanical fatigue. The analysis of EDS indicated no oxidation wear generated during the machining. The excellent chemical stability and oxidation resistance performance of TiAlN coating made contribution to prevent oxidation wear.

Abstract: Ball-end milling of Cr12MoV die steel was studied using ceramic and cemented carbide inserts under different cutting conditions. The cutting forces, wear patterns and chip patterns generated using the different cutting tools at the different cutting conditions were investigated using a three component piezoelectric dynamometer and VHX-600E large depth-of-view 3-D scanner. The relationships among the cutting forces, wear patterns and chip patterns were discussed. The results indicated that the cutting forces caused by the ceramic insert were slightly lower than those caused by the cemented carbide insert under the same cutting conditions. For ceramic inserts, effects of cutting conditions on the rake face wear were different from those on the flank wear. The higher wear for the ceramic insert was caused at the lower cutting conditions but the higher wear for the cemented carbide insert was encountered at the higher cutting conditions. The squeezed chip was involved with the higher cutting forces. The sharper cutting edge of the cemented carbide insert was responsible for chip patterns caused by the No. I cutting condition. The effects of cutting conditions on wear patterns were more evident than that on chip patterns.

Abstract: The machining efficiency of titanium alloy Ti6Al4V is low and the tool wear is serious. In this paper, uncoated carbide tool and two kinds of coated cemented carbide tool were used for dry turning titanium alloy. The experiments used CCD Observing System and the EDAX analysis of SEM to study tool wear mechanism and analyze the cutting performance through tool life, cutting force and cutting temperature. The results show that the main wear reasons are adhesion, diffusion and oxidation wear. For coated tool, the coating peeled off first, and then tool substrate damaged. Compared with coated carbide tool, the uncoated carbide tool with fine grain has longer tool life and lower cutting force and cutting temperature. The changes of cutting force and cutting temperature with cutting speed are not obvious when using the ccomposite coating (TiAlN and AlCrN) carbide tool. The results can help to choose tool material reasonably and control tool wear.

Abstract: Superalloys (also as known as Aero-engine alloys)are known as difficult-to-machine materials, especially at higher cutting speeds, due to their several inherent properties such as low thermal conductivity and their high reactivity with cutting tool materials. In this paper , the adhesion wear of cemented carbide tool when machining GH907 was studied with white light interferometer, infrared imaging, and SEM-EDS. The adhesion wear morphology wear mechanism and the wear rule of adhesion were analyzed, and the effect of different cutting time and different cutting speed on adhesive wear were analyzed which will provide useful references for the optimization of cutting parameters and the improvement of the tool life.

Abstract: Working fluid is commonly used in the making and using progress of cemented carbide tool. The tungsten carbide leaching of cemented carbide tool will be resulted in by the sodium carbonate in cutting fluid, because of the tungsten carbide will occur oxidative dissolution. The inhibitor that suppress tungsten carbide leaching of cemented carbide tool is investigated by soaking experiments, friction experiments, SEM analysis, and energy spectrum analysis. The test result shows that aqueous solution and sodium carbonate will cause tungsten carbide leaching through oxidative dissolution; but compound boricacidester contain benzotriazole could suppress tungsten carbide leaching. The Inhibition mechanism is that compound boricacidester contain benzotriazole could generate complete and compact protective film on the surface of cemented carbide tool, therefore, tungsten carbide leaching is inhibited. Add compound boricacidester contain benzotriazole to the water-based cutting fluid could suppress tungsten carbide leaching effectively.

Abstract: In the cutting progress, the cutting temperature and the friction will be reduced when the water-based cutting fluid is used, but some elements in the cutting fluid will result in the leaching of tungsten carbide in cemented carbide tool. The influence rule of sodium carbonate on the tungsten carbide leaching of cemented carbide under the condition of different temperatures and different concentrations is investigated by soaking experiments, SEM analysis, energy spectrum analysis and electrochemical detection experiments. The experimental results reveal that the influence of sodium carbonate on the tungsten carbide leaching are great, and the leaching rate will increase with the increasing of temperature and concentration.

Abstract: The influence of some commonly used inhibitors on the tungsten carbide leaching of the cemented carbide tool was studied by energy spectrum analysis and electrochemical gaging. And the mechanism of the tungsten carbide leaching and be inhibited of the cemented carbide was discussed. The test results showed that when cemented carbide tool were soaked in tri-sodium phosphate and sodium carbonate anhydrous the tungsten carbide in the cemented carbide tool leached out for hydration. And benzotriazole has a good inhibitory effect on the tungsten carbide leaching of the cemented carbide tool.

Abstract: Damage of fine grained hard metals WC-10%Co was investigated using the laser thermal shock method. Cemented carbide insert was irradiated with a high power laser and scanning electron microscopy was used to characterize the damage in the surface. Stress was analysis with thermo-elastic theory after thermal shock cycles. Crack initiation of cemented carbide was primarily induced by high thermal shock cycles under high rotation speed and low feed rate. Tangential stress played a primary role in crack initiation and it was demonstrated that why the thermal cracks always perpendicular to the cutting edge.