High speed steel
High speed steel (HSS) is a type of tool steel known for its high hardness, wear resistance and heat resistance.
It can be hardened even when cooled in air during the tempering process and is known for its sharpness, also known as “white steel”.
HSS is a complex steel alloy that contains carbide-forming elements such as tungsten, molybdenum, chromium, vanadium and cobalt, with the total amount of alloying elements making up about 10-25% of the steel.
One of its defining characteristics is “red hardness”, the ability to maintain high hardness even under high temperatures generated by high-speed cutting (around 500°C), resulting in a hardness greater than 60 on the Rockwell scale (HRC).
In comparison, carbon tool steel can have high hardness at room temperature after quenching and tempering at low temperatures, but its hardness decreases sharply when temperatures exceed 200°C and is similar to the annealed state at 500°C. This sharp decrease in hardness limits the use of carbon steel for cutting tools.
HSS, with its good red hardness, compensates for this deficiency of carbon tool steel.
It is mainly used to make complex, fine-edged, impact-resistant cutting tools, as well as high-temperature bearings and cold extrusion dies, such as turning tools, drills, milling cutters, machine blades and demanding dies.
Tungsten Steel
Tungsten steel, also known as hard alloy, has a range of excellent properties, including high hardness, wear resistance, good strength and toughness, heat resistance and corrosion resistance, particularly its high hardness and wear resistance.
Even at temperatures as high as 500°C, its properties remain practically unchanged and it still maintains high hardness at 1000°C.
Tungsten steel is composed of tungsten carbide and cobalt as the main components, accounting for 99% of the material, with the remaining 1% consisting of other metals. This is why it is also known as tungsten steel.
Also known as carbide, it is considered the backbone of modern industry.
Tungsten steel is a composite material made from at least one metal carbide, with tungsten carbide, cobalt carbide, niobium carbide, titanium carbide and tantalum carbide being the most common components.
The grain size of the carbide component is typically between 0.2 and 10 microns, and the carbide grains are held together by a metal binder, usually an iron group metal, with cobalt and nickel being the most frequently used .
Thus, there are tungsten-cobalt alloys, tungsten-nickel alloys and tungsten-titanium-cobalt alloys.
The tungsten steel manufacturing process involves pressing the powder into a billet, heating it to a specific temperature (the sintering temperature) in a sintering furnace, holding it at that temperature for a specified time, and then cooling it to get the final tungsten steel material. with the desired properties.
① Tungsten-Cobalt Cemented Carbide
Tungsten steel consists of tungsten carbide (WC) and cobalt binder (Co) as its main components.
Its grade is indicated by the prefix “YG” (which means “hard and cobalt” in Chinese pinyin) and the average percentage of cobalt content.
For example, YG8 indicates an average of 8% cobalt content, with the remaining composition being tungsten-cobalt based cemented carbide and tungsten carbide.
②Tungsten-titanium-cobalt-based hard alloy
The main components of tungsten steel are tungsten carbide, titanium carbide (TiC) and cobalt.
Its grade is indicated by the prefix “YT” (meaning “hard, titanium” in Chinese pinyin) and the average percentage of titanium carbide content.
For example, YT15 indicates an average of 15% titanium carbide content, with the remaining composition being tungsten carbide and tungsten-titanium-cobalt cemented carbide.
③ Hard alloy based on tungsten-titanium-tantalum (niobium)
The main components of tungsten steel are tungsten carbide, titanium carbide, tantalum carbide (or niobium carbide) and cobalt.
This type of carbide is also known as universal carbide.
Its grade is indicated by the prefix “YW” (which means “hard” and “wan” in Chinese Pinyin) and a sequence number, such as YW1.
Tungsten steel has a range of excellent properties, including high hardness, wear resistance, good strength and toughness, heat resistance and corrosion resistance, particularly its high hardness and wear resistance.
Even at temperatures as high as 500°C, its properties remain practically unchanged and it still maintains high hardness at 1000°C.
Carbide is widely used as a material in tools such as turning tools, milling tools, drills and boring tools, and the cutting speed of this new type of hard alloy is hundreds of times faster than that of carbon steel.
