Today, Huilisheng's editor will take you through the differences between high-speed steel (HSS) cutting blades and tungsten steel (carbide) cutting blades.
High-Speed Steel (HSS) Cutting Blades
High-speed steel is a type of tool steel known for its high hardness, wear resistance, and heat resistance. It is also called "air-hardening steel" or "sharp steel," indicating that it can harden even when cooled in air during quenching and remains very sharp. It is sometimes referred to as "white steel."
High-speed steel is a complex alloy steel containing carbide-forming elements such as tungsten, molybdenum, chromium, vanadium, and cobalt. The total alloy content is approximately 10–25%. It retains high hardness (above HRC 60) even under the high heat generated during high-speed cutting (around 500°C). This is the most critical characteristic of high-speed steel—red hardness. In contrast, carbon tool steel, after quenching and low-temperature tempering, exhibits high hardness at room temperature but experiences a sharp decline in hardness above 200°C. At 500°C, its hardness drops to a level similar to its annealed state, completely losing its ability to cut metal. This limitation restricts carbon tool steel's use in cutting tools. The excellent red hardness of high-speed steel overcomes this critical shortcoming of carbon tool steel.
High-speed steel is primarily used to manufacture complex thin-edged metal-cutting tools and impact-resistant tools, as well as high-temperature bearings and cold extrusion molds. Examples include lathe tools, drills, hobs, machine saw blades, and high-demand molds.
Tungsten Steel (Carbide) Cutting Blades
Tungsten steel (carbide) cutting blades possess a series of excellent properties, including high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance. Notably, their high hardness and wear resistance remain largely unchanged even at 500°C, and they retain significant hardness at 1000°C. The primary components of tungsten steel are tungsten carbide and cobalt, which account for 99% of its composition, with the remaining 1% being other metals. Hence, it is called tungsten steel or hard alloy, often regarded as the "teeth of modern industry."
Tungsten steel cutting blades are sintered composite materials consisting of at least one metal carbide. Common components include tungsten carbide, cobalt carbide, niobium carbide, titanium carbide, and tantalum carbide. The grain size of the carbide components typically ranges from 0.2 to 10 micrometers. These carbide grains are bonded together using a metallic binder, usually from the iron group, with cobalt and nickel being the most common. This results in alloys such as tungsten-cobalt, tungsten-nickel, and tungsten-titanium-cobalt.
The sintering process for tungsten steel involves pressing powder into a blank, heating it in a sintering furnace to a specific temperature (sintering temperature), holding it for a certain time (soaking time), and then cooling it to obtain the desired tungsten steel material.
Classification of Common Tungsten Steel (Hard Alloy):
Tungsten-Cobalt Hard Alloys: The main components are tungsten carbide (WC) and the binder cobalt (Co). Their grade designation consists of "YG" (from the Chinese pinyin initials for "hard" and "cobalt") followed by the average cobalt percentage. For example, YG8 indicates a tungsten-cobalt hard alloy with an average cobalt content of 8%, with the remainder being tungsten carbide.
Tungsten-Titanium-Cobalt Hard Alloys: The main components are tungsten carbide, titanium carbide (TiC), and cobalt. Their grade designation consists of "YT" (from the Chinese pinyin initials for "hard" and "titanium") followed by the average titanium carbide content. For example, YT15 indicates a tungsten-titanium-cobalt hard alloy with an average TiC content of 15%, with the remainder being tungsten carbide and cobalt.
Tungsten-Titanium-Tantalum (Niobium) Hard Alloys: The main components are tungsten carbide, titanium carbide, tantalum carbide (or niobium carbide), and cobalt. These are also called general-purpose or universal hard alloys. Their grade designation consists of "YW" (from the Chinese pinyin initials for "hard" and "universal") followed by a serial number, such as YW1.
Tungsten steel exhibits excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance. Its high hardness and wear resistance remain largely unchanged even at 500°C, and it retains significant hardness at 1000°C. Hard alloys are widely used as tool materials, including lathe tools, milling cutters, drills, and boring tools. The cutting speed of new hard alloys can be hundreds of times faster than that of carbon steel.
