For a long time, many people in the industry have believed that cemented carbide is tungsten steel. Today we will talk about the difference between cemented carbide and tungsten steel.
01 Cemented carbide
Cemented carbide is made of hard compounds of refractory metals and bonding metals through powder metallurgy, and is an alloy material with extremely high hardness. Tungsten carbide (WC) is the main component of cemented carbide, accounting for 70%-97% of the total composition; the binder metal is used for bonding in the alloy, and the content is usually 3%-30%. During the sintering process, It can surround and bond the tungsten carbide powder tightly together, and it becomes a cemented carbide after cooling.
Therefore, commonly used cemented carbides are divided into three categories according to their composition and performance characteristics: tungsten-cobalt, tungsten-titanium-cobalt, and tungsten-titanium-tantalum (niobium). The most widely used in production are tungsten-cobalt and tungsten-titanium-cobalt cemented carbides.
1) Tungsten-cobalt carbide
The main components are tungsten carbide (WC) and cobalt. The grades are represented by the code name YG ("hard" and "cobalt" in Chinese pinyin prefix), followed by the percentage of cobalt content. For example, YG6 represents a tungsten-cobalt cemented carbide with a cobalt content of 6%, and a tungsten carbide content of 94%.
2) Tungsten-titanium-cobalt cemented carbide
The main components are tungsten carbide (WC), titanium carbide (TiC) and cobalt. The grades are represented by the code name YT ("hard" and "titanium" in Chinese pinyin prefix), followed by the percentage of titanium carbide content. For example, YT15 represents a tungsten-titanium-cobalt cemented carbide with 15% titanium carbide content.
3) Tungsten titanium tantalum (niobium) hard alloy
This kind of cemented carbide is also called general cemented carbide or universal cemented carbide. The main components are tungsten carbide (WC), titanium carbide (TiC), tantalum carbide (TaC) or niobium carbide (NbC) and cobalt. The grades are represented by the code YW (the initials of the Chinese pinyin of "hard" and "wan") followed by an ordinal number.
Commonly used cemented carbide grades and chemical composition:
Note: "X" after the brand name means fine-grain alloy, "C" means coarse-grain alloy, and no word refers to general-grain alloy.
02 The difference between tungsten steel and cemented carbide
Generally speaking, tungsten steel is smelted by adding tungsten raw materials into molten steel by a steelmaking process. It is also called high-speed steel or tool steel, and its tungsten content is generally 15-25%. In addition to the production of high-speed steel by the smelting method, there are also powder metallurgy high-speed steels, which avoid the segregation of carbides caused by the smelting method to cause mechanical properties and heat treatment deformation.
The cemented carbide is sintered with cobalt or other bonding metals using powder metallurgy technology with tungsten carbide as the main body, and its tungsten content is generally more than 80%.
Simply put, all alloys with a hardness exceeding HRC65 can be called cemented carbide, so tungsten steel belongs to cemented carbide; but strictly speaking, cemented carbide is not necessarily tungsten steel.
