For a long time, many people in the industry think that cemented carbide is tungsten steel. Today we will talk about the difference between cemented carbide and tungsten steel.
01 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; bonding metal is used for bonding in the alloy, and the content is usually 3%-30%. During the sintering process, It can surround and tightly bond tungsten carbide powder together, and it becomes 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 carbide.
1) Tungsten-cobalt cemented carbide
The main components are tungsten carbide (WC) and cobalt. The grade is represented by the code YG (the initials of the two characters "hard" and "cobalt" in Chinese pinyin), followed by the percentage value of the cobalt content. For example, YG6 means 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 grade is represented by the code YT (the initials of the two characters "hard" and "titanium" in Chinese pinyin), followed by the percentage value of titanium carbide content. For example, YT15 means tungsten-titanium-cobalt cemented carbide with a titanium carbide content of 15%.
3) Tungsten-titanium-tantalum (niobium)-based cemented carbide
This type of cemented carbide is also called general-purpose 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 grade is represented by the code YW (the initials of the two characters "hard" and "wan" in Chinese pinyin) followed by an ordinal number.
The grade and chemical composition of commonly used cemented carbide:
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Note: "X" after the designation means fine-grained alloy, "C" means coarse-grained alloy, and no word means general-grained 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 steelmaking process, also known as high-speed steel or tool steel, and its tungsten content is generally 15-25%. In addition to the production of high-speed steel by smelting, there is also powder metallurgy high-speed steel, which avoids the reduction of mechanical properties and heat treatment deformation caused by carbide segregation caused by smelting.
Cemented carbide is sintered with tungsten carbide as the main body and cobalt or other bonding metals by powder metallurgy process, and its tungsten content is generally above 80%.
Simply put, all alloys with a hardness exceeding HRC65 can be called cemented carbide, so tungsten carbide belongs to cemented carbide; but strictly speaking, cemented carbide is not necessarily tungsten carbide.
