What is the Difference Between the High Speed Steel and Carbide Alloy?

1. High-speed steel (HSS)

It is a tool steel with high hardness, high wear resistance and high heat resistance, also known as the air hardening steel or rapid steel, which means that it can be hardened even if it is cooled in the air during quenching, and it is very sharp. It is also called white steel.

High-speed steel is an alloy steel with complex composition, containing carbide forming elements such as tungsten, molybdenum, chromium, vanadium, and cobalt. The total amount of alloying elements is about 10 to 25%. It can maintain high hardness even when high heat is generated by high-speed cutting (about 500℃), and the HRC can be above 60. This is the most important characteristic of high-speed steel - Red hardness.

After quenching and low-temperature tempering, carbon tool steel has high hardness at room temperature, but when the temperature is higher than 200℃, the hardness drops sharply, and the hardness at 500℃ has dropped to a similar degree to the annealed state, which means it has completely lost the ability to cut metal. What's more, the use of carbon tool steel to make cutting tools is limited. The high-speed steel, because of its good red hardness, makes up for the fatal shortcomings of carbon tool steel.

High-speed steel is mainly used to manufacture 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 saw blades, and demanding molds.

2. Carbide alloy (hard alloy)

It 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 can remain basically unchanged even at a temperature of 500 ℃. It still has high hardness at 1000℃.

Carbide alloy, whose main components are tungsten carbide and cobalt, which account for 99% of all components (and 1% is other metals), is called tungsten steel, also known as cemented carbide, and is considered to be the teeth of modern industry.

Carbide alloy is a sintered composite material composed of at least one metal carbide. Tungsten carbide, cobalt carbide, niobium carbide, titanium carbide, and tantalum carbide are common components of the carbide alloy. The grain size of the carbide component (or phase) is usually between 0.2 to 10 microns, and the carbide grains are bonded together using a metal binder. The bonding metal is generally iron group metal, and cobalt and nickel are commonly used. So there are tungsten-cobalt alloys, tungsten-nickel alloys and tungsten-titanium-cobalt alloys.

The sintering molding of carbide alloy is to press the powder into a blank, then heat it in a sintering furnace to a certain temperature (sintering temperature), keep it for a certain time (holding time), and then cool it down to obtain the tungsten steel material with the required performance.

①Tungsten-cobalt cemented alloy

The main components are tungsten carbide (WC) and binder cobalt (Co). The mark is composed of "YG" (the initials of the Chinese pinyin of "hard and cobalt") and the percentage of the average cobalt content. For example, YG8 means that the average WCo=8%, and the rest is tungsten-cobalt cemented alloy of tungsten carbide.

②Tungsten-titanium-cobalt cemented alloy

The main components are tungsten carbide, titanium carbide (TiC) and cobalt. The mark consists of "YT" (the initials of the Chinese pinyin of "hard and titanium") and the average content of titanium carbide. For example, YT15 means that the average TiC=15%, and the rest is tungsten carbide and cobalt tungsten-titanium-cobalt cemented alloy.

③Tungsten-titanium-tantalum (niobium) cemented alloy

The main components are tungsten carbide, titanium carbide, tantalum carbide (or niobium carbide) and cobalt. This kind of cemented alloy is also called general cemented alloy or universal cemented alloy. The mark is composed of "YW" (the initials of the Chinese pinyin of "hard" and "universal") plus a sequence number, such as YW1.

Carbide 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 can remain basically unchanged even at a temperature of 500°C. It still has a high hardness at 1000°C. Cemented alloy is widely used as a material, such as turning tools, milling cutters, drill bits, boring cutters, etc. The cutting speed of the new cemented alloy is hundreds of times that of carbon steel.