The application range of common cemented carbide
Cemented carbide is an alloy material made from refractory metal carbides (such as WC and TiC) and a binder (such as Co) through a powder metallurgy process. It features high hardness (HRA85-93), excellent wear resistance, and high-temperature resistance, playing an irreplaceable role in metal cutting, mining, mold manufacturing, and other fields. Commonly used cemented carbides can be divided into tungsten-cobalt (WC-Co), tungsten-titanium-cobalt (WC-TiC-Co), and tungsten-titanium-tantalum (niobium) (WC-TiC-TaC-Co) based on their composition and properties. Each type of cemented carbide has its own unique performance characteristics and application range, providing precisely matched solutions for the processing needs of different materials and processes.
Tungsten-cobalt cemented carbide (codenamed YG) is the most widely used type of cemented carbide. Its primary components are tungsten carbide (WC) and cobalt (Co), with the cobalt content typically ranging from 3% to 20%. Lower cobalt content increases the alloy’s hardness and wear resistance, but also reduces its flexural strength. Conversely, higher cobalt content increases flexural strength and improves toughness. YG3, YG6, and YG8 are commonly used grades. YG3, with a 3% cobalt content and a hardness of HRA91, is suitable for finishing brittle materials such as cast iron and non-ferrous metals. YG6, with a 6% cobalt content and a hardness of HRA89.5, is suitable for semi-finishing and finishing of cast iron. YG8, with an 8% cobalt content and a hardness of HRA89, has a flexural strength of 1400 MPa and is suitable for roughing and interrupted cutting of materials such as cast iron and bronze, such as milling cast iron blanks. Tungsten-cobalt cemented carbide has poor heat resistance (operating temperature ≤ 800℃), but has strong ability to withstand impact loads and has obvious advantages in low-speed, heavy-load cutting situations.
Tungsten-titanium-cobalt cemented carbide (codenamed YT) is a ternary WC-TiC-Co alloy with titanium carbide (TiC). The addition of TiC improves the alloy’s heat resistance and oxidation resistance, allowing it to operate at temperatures up to 900-1000°C, but with some reduction in toughness. Common grades include YT5, YT15, and YT30, with TiC contents of 5%, 15%, and 30%, respectively. Increasing TiC content increases hardness but decreases bending strength. YT5, with its low TiC content and good toughness, is suitable for rough machining of carbon and alloy steels. YT15, with its excellent overall performance, is suitable for semi-finishing and finishing of carbon steel and is widely used in machining 45 steel shafts on conventional lathes. YT30, with its highest TiC content and a hardness of HRA92.5, is suitable for high-speed cutting and finishing, such as cutting quenched and tempered steel at speeds of 100-150 m/min on CNC lathes. Tungsten-titanium-cobalt cemented carbide has low affinity for steel and is not prone to tool sticking, making it an ideal material for processing ferrous metals.
Tungsten-titanium-tantalum (niobium) cemented carbide (codenamed YW) combines the toughness of YG with the heat resistance of YT, allowing for operating temperatures exceeding 1000°C. It can process both ferrous and non-ferrous metals, hence the name “universal.” Common grades are YW1 and YW2. YW1 contains 3%-4% TaC (NbC), boasts a hardness of HRA91.5, and a flexural strength of 1500 MPa, making it suitable for semi-finishing and finishing of difficult-to-machine materials such as high-strength and heat-resistant steels. YW2, with a 1%-2% TaC (NbC) content, offers improved toughness compared to YW1 and is suitable for roughing and interrupted cutting of difficult-to-machine materials such as stainless steel and high-manganese steel. In practical applications, YW cemented carbide offers a high cost-effectiveness and reduces tool changes, making it particularly suitable for machining workshops with high-variety, low-volume production.
Specialized cemented carbides are designed for specific machining scenarios, expanding their application range. For example, ultrafine-grained cemented carbides (grain size ≤ 0.5μm) offer enhanced hardness and wear resistance, making them suitable for precision machining and high-speed cutting, such as micro-tools for machining electronic components. Coated cemented carbides are coated with wear-resistant coatings such as TiN and TiAlN (3-10μm thick) to further enhance their wear and heat resistance, extending their service life by 2-5 times that of uncoated alloys. These materials are widely used in CNC machine tools. Cermets, primarily composed of TiC and TiN combined with a metal binder, exhibit extremely high red hardness and are suitable for high-speed precision turning of alloy steels. With the advancement of materials science, new cemented carbides are constantly emerging, such as nanocomposite cemented carbides and gradient structure cemented carbides, providing more advanced tool solutions for machining difficult-to-machine materials in aerospace, new energy, and other fields.
