Metal Cutting Tools Materials--Cemented Carbide

Cemented carbide is a carbide hardness and high melting point (known as the hard phase) and a metal (called the binder phase) made by powder metallurgy process. Cemented carbide tool commonly uses carbide such as WC, TiC, TaC, NbC. The adhesive generally used is Co, titanium carbide-based adhesive is Mo, and Ni.

Cemented carbide performance

Cemented carbide physical and mechanical properties depend on the alloy composition and thickness of the powder particles as well as alloy sintering process. Containing the more hard phase of high hardness, high melting point, the higher the hardness and high-temperature hardness of the alloy. Containing the more binder, the higher strength. Alloy, TaC, NbC beneficial grain refinement, and to improve the heat resistance of the alloy. Contains a large amount of WC, TiC, therefore the hardness, wear resistance, heat resistance are higher than the tool steel commonly used cemented carbide tool grades. Hardness at room temperature up to 89 ~ 94HRA, heat resistance up to 800 to 1000 ℃. Cutting steel cutting speed of up to 220m/min. TaC, NbC, was added in the alloy with higher melting point, heat resistance can be increased to 1000 to 1100 ° C, when cutting steel, the cutting speed can be further improved in 200-300m/min.

Cemented carbide can be divided into three categories:

K class, tungsten, cobalt class (WC + Co): bending strength and toughness than the P-class, able to withstand the impact of carbide cutting tool, can reduce chipping cut white cut, but the heat is worse than the P-classmainly used for machining cast iron, non-ferrous materials and non-metallic materials. Was chipping like chips when machining brittle materials. Class K alloy good thermal conductivity; help to reduce the cutting temperature. In addition, this type of cemented carbide tool grinding, sharpening a sharp edge, it is also suitable for the processing of non-ferrous materials and fiber laminate material.

Class P, tungsten, titanium drill class (WC + TiC + Co): higher hardness, especially those with high heat resistance, preferred anti-adhesive, anti-oxidation ability. In the processing of steel, plastic deformation, violent friction, higher cutting temperatures appears. Wear slower, carbide tool life high. Cemented carbide containing TiC content more persons, containing a small amount of Co, abrasion resistance, heat resistance, better suited to finishing. But TiC increase in volume for a long time, alloy thermal deteriorates, welding and grinding prone to cracks. Containing TiC small amount, and is suitable for roughing.

M class, add the rare metal carbides class (WC + TiC + TaC (NbC) + Co): adding an appropriate amount of rare insoluble metal carbides, to improve the performance of the alloy. Type of cemented carbide tool, a significant effect of the addition of TaC or NbC, the general mass fraction of about 4%. TaC or NbC main role is in the alloy to improve the alloy's high temperature hardness and high-temperature strength. TaC, of YG cemented carbide cutting tool enable the strength of about 0.15-0.20GPa 800 ℃. In YT classes alloy TaC, the addition of high-temperature hardness can be increased by about 50 to 100HV.

Fine-grained, ultra-fine grain alloy

Ordinary carbide WC grain size is several microns, the fine grain alloy Average particle size of about 1.5μm. Ultrafine grain alloy particle size between 0.2 and 1 μm, most of which is 0.5 μm or less.

Fine grain alloy due to the hard phase and the binder phase is highly dispersed and increase the bonded area, improve the bond strength. Therefore, its hardness and strength than alloys of the same ingredients, the hardness increases by about 1.5 ~ 2HRA bending strength increases by about 0.6 ~ 0.8GPa, and high-temperature hardness can improve. Chipping phenomenon can be reduced in low-speed cutting.

The production of ultra-fine grain alloy must use fine WC powder should also add trace Yang preparations to control the grain growth. And the use of advanced sintering process, the cost is higher.

The use of ultra-fine grain cemented carbide occasion:

1) high hardness, high strength material difficult processed materials;

2) interrupted cutting of difficult to machine materials, such as milling, etc.;

3) low-speed cutting cemented carbide cutting tool, such as the cutting knife, small drill, forming knife;

4) requires a larger anterior horn, posterior horn, smaller nose radius can thin layer cutting precision cemented carbide cutting tool, such as reamers, broaches,cemented carbide cutting tool.

Steel bonded cemented carbide

Steel bonded cemented carbide WC, TiC hard phase, high-speed steel binder phase, made by powder metallurgy process. It forging, machining, heat treatment and welding. Quenched hardness higher than the high-productivity, high-speed steel, strength, toughness than cemented carbide. Steel bonded cemented carbide can be used in the manufacture of molds, broaches, milling the complex shape of the tool or cemented carbide cuttingtool.

Coated cemented carbide

The coated cemented carbide early 1960s. Refractory metal carbides by chemical vapor deposition (CVD) process, in the cemented carbide surface is coated with one or more layers (5 ~ 13μm). Good overall performance, good toughness of the matrix strength alloys coating, surface wear-resistant, high temperature. Degree of coated carbide sharp edge chipping resistance is less than ordinary cemented carbide tool. Coated cemented carbide tool is widely used in ordinary steel finishing and semi-finishing and roughing. Coating material includes TiC, TiN, TiCN, Al2O3 and its composites. The coated cemented carbide is a composite material; the substrate is preferably alloy strength, toughness, while the surface layer is a high hardness, high wear resistance, high temperature, low friction material. The new material is effective to improve the overall performance of the alloy, this type of cemented carbide cutting tool developed rapidly. It is widely applicable to cemented carbide cutting tool, such as higher precision indexable blade, turning, milling cutters, drills, reamers.

Chinatungsten Online can provide various sizes and grades of cemented carbide cutting tool,non-standard products are also customized according to customer requirements. Welcome to consult and purchase [email protected], [email protected] .