High Speed Steel
High speed steel (HSS) is a tool steel with high hardness, high wear resistance and high heat resistance.
It can harden even when cooled in air during quenching, and is very sharp. It also been called white steel.
High-speed steel is a complex alloy steel containing carbide-forming elements such as tungsten, molybdenum, chromium, vanadium, and cobalt.
The total amount of alloying elements is about 10-25%.
It can still maintain high hardness under the condition of high heat generated by high-speed cutting (about 500 ℃), and HRC can be above 60.
This is the main characteristic of high-speed steel – red hardness.
After quenching and tempering at low temperature, although carbon tool steel has a high hardness at room temperature, but when the temperature is higher than 200 °C, the hardness decreases sharply, and at 500 °C, the hardness has decreased to a similar degree to the annealed state.
The complete loss of the ability to cut metal has limited the use of carbon tool steel to make cutting tools.
The high-speed steel has good red hardness, which makes up for the fatal shortcomings of carbon tool steel.
High-speed steel is mainly used to make complex thin-edged and impact-resistant metal cutting tools.
It can also manufacture high-temperature bearings and cold extrusion dies, such as turning tools, drills, hobs, machine blades and demanding dies.
Tungsten steel (hard alloy) has a series of excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance and corrosion resistance, especially its high hardness and wear resistance.
Even at a temperature of 500 °C, it remains basically unchanged, and still has high hardness at 1000 °C.
Tungsten steel, whose main components are tungsten carbide and cobalt, accounts for 99% of all components, and 1% is other metals, so it is called tungsten steel.
Also known as cemented carbide, it is considered the tooth of modern industry.
Tungsten steel is a sintered composite material containing at least one metal carbide.
Tungsten carbide, cobalt carbide, niobium carbide, titanium carbide, and tantalum carbide are common components of tungsten steel.
The grain size of the carbide component (or phase) is usually between 0.2 and 10 microns, and the carbide grains are bonded together using metal binder.
The bonding metal is generally an iron group metal, and cobalt as well as nickel are commonly used.
Therefore, there are tungsten-cobalt alloys, tungsten-nickel alloys, and tungsten-titanium-cobalt alloys.
Tungsten steel sintering molding is to press the powder into a billet, next, heat it to a certain temperature (sintering temperature) in a sintering furnace, then hold it for a certain time (holding time), and after the above, cool it down to obtain the tungsten steel material with the required properties.
① Tungsten-Cobalt Cemented Carbide
The main components are tungsten carbide (WC) and binder cobalt (Co).
Its grade is composed of “YG” (“Hard and Cobalt” Chinese Pinyin prefix) and the average percentage of cobalt content.
For example, YG8 means an average WCo = 8%, and the rest is tungsten-cobalt-based cemented carbide with tungsten carbide.
② Tungsten-titanium-cobalt-based hard alloy
The main components are tungsten carbide, titanium carbide (TiC) and cobalt.
Its grade consists of “YT” (“Hard, Titanium” Chinese Pinyin prefix) and the average content of titanium carbide.
For example, YT15 means that the average TiC = 15%, and the rest are tungsten carbide and tungsten-titanium-cobalt cemented carbide with cobalt content.
③ Tungsten-titanium-tantalum (niobium)-based hard alloy
The main components are tungsten carbide, titanium carbide, tantalum carbide (or niobium carbide) and cobalt.
This type of cemented carbide is also called universal cemented carbide or universal cemented carbide.
Its grade is composed of “YW” (“Hard” and “Wan”, Chinese Pinyin prefix) and sequence number, such as YW1.
Tungsten steel has a series of excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance and corrosion resistance, especially its high hardness and wear resistance.
It remains basically unchanged even at a temperature of 500 °C, and still has a high hardness at 1000 °C.
Carbide is widely used as materials, such as turning tools, milling tools, drills, boring tools, etc.
The cutting speed of the new type of hard alloy is hundreds of times that of carbon steel.