Cemented Carbide Vs Tungsten Steel
In the past, people usually mistook cemented carbide for tungsten steel. However, there are so many differences between the two. This is why we have decided to look at the differences between cemented carbide and tungsten steel.
Cemented Carbide
Cemented carbide is one of the best engineering materials ever made. It is an alloy made from a binder metal and a hard-compound of a refractory metal through a powder metallurgy process. It is used as a cutting tool material and as well as in other industrial applications.
Properties of Cemented Carbide
Cemented carbide has a series of excellent properties. Some of them are:
- High hardness
Cemented carbide has a very high hardness. The hardness of cemented carbide is HRA89-94, and this is higher than that of High-Speed Steel (HRC63-70 or HRA83-86.6). The high-temperature hardness of cemented carbide is about HRA82-87 at 540 °C, which is the same temperature hardness of high-speed steel at room temperature.
- High Strength
Cemented carbide has higher yield strength; hence it has good resistance to plastic deformation. In comparison to steel and other materials, it also has a higher compressive strength. The strength value of cemented carbide increases with the decrease of binder content and grain size.
- Good toughness
Cemented carbide has a relatively fair toughness which explains its use in many industrial applications. The toughness range extends from 700 up to 2200 HV30. This toughness also decreases with increasing temperature.
- Excellent wear resistance
It is one of the characteristics of cemented carbide. Because of its excellent wear resistance even at higher temperatures, cemented carbide is widely used for wood machining, metal cutting and rock drilling.
- Heat resistance.
Cemented carbide has a very good heat resistance and is highly suitable in very high temperatures.
6. Fatigue strength
Cemented carbide has a very high fatigue strength. This is important because the fatigue strength as a proportional relationship with the surface quality of the sample. The higher the fatigue strength, the better the surface finish.
Cemented carbide has a unique blend of hardness, strength and toughness. These properties are enough to satisfy the most demanding industrial applications.
Another feature of cemented carbide is the ability to alter its composition to having chemical and physical properties that guarantee corrosion resistance, wear, fracture, oxidation and deformation.
Uses of Cemented Carbide
Cemented carbide can be used to make mining tools, drilling tools, gauges, metal grinding, wear-resistant parts, precision bearings, cylinder liners, nozzles, hardware molds (molds such as bolts, nut molds).
Other products made with cemented carbide include carbide rods, carbide plates, carbide bushings, carbide rings, carbide balls, carbide nozzles, valves and non-standard carbide parts. These products have value in industries like the oil and natural gas industry, New Energy, aerospace; Steel smelting, military industry, Coal mining, Auto parts industry and the Chemical industry.
What is Tungsten Steel?
Tungsten steel is a type of metal alloy made from a combination of tungsten and iron. Its tungsten content is generally 15-25%.
The addition of tungsten to the alloy gives it increased hardness and resistance to heat. Hence any equipment made from tungsten steel to maintain high performance and to resist wear at high temperatures. The main advantage of tungsten steel lies in its high hardness and excellent wear resistance. It can still have high hardness even at 1000°C. The grain size of the carbide component is usually between 0.2-10 microns.
Tungsten steel is valued for its industrial uses as tool steel. It is why it is used in industrial tools and machinery for working other metals, such as dies and cutting tools.
In simpler terms, all alloys with a hardness exceeding HRC65 can be called cemented carbide. Hence, tungsten steel belongs to cemented carbide, but strictly speaking, cemented carbide is not necessarily tungsten steel.
Types of Tungsten Carbide
There are 3 different types of tungsten carbide;
- Tungsten-cobalt,
The main components here are tungsten carbide and binder cobalt
- Tungsten-titanium-cobalt
The main components are tungsten carbide, titanium carbide and cobalt.
- Tungsten-titanium-tantalum (niobium)
The main components are tungsten carbide, titanium carbide, niobium carbide and cobalt.
Properties of Tungsten Steel
- High Density
Tungsten steel has a high density of 19.24 grams/centimetres.
- High Melting Point
It has a very high melting point of 6192°F (3422°C).
- High Boiling Point
It has a very high boiling point of 10031°F (5555°C).
- High Hardness
Tungsten steel has a Moh’s Hardness value of 7.5. It has a hardness that is four times titanium hardness and seven times of stainless steel. It is just behind diamond in terms of hardness.
- Highest Tensile Strength
It has the highest tensile strength at temperatures above 1650°C.
- Less Expansion Coefficient
Tungsten steel has less expansion than other pure metals from heat.
- A High Corrosive Resistance
It has very high corrosion resistance. Using the artificial sweat test, there was no change in colour, corrosion, fading and rusting.
- A High Wear Resistance
Tungsten steel has good wear resistance and can be used to process cast iron, stainless steel and other hard metal materials.
Uses of Tungsten steel
- Tungsten-Steel used in high-speed applications like in those used in cutting and machining tools. A perfect example is the saw blade. These tools usually contain around 18% tungsten.
- Tungsten-steel is used in the commercial production of rocket engine nozzles. This application is due to its high heat resistant properties.
- Inserts and drill bits: Tungsten steel is used to make drills in the construction industry.
- Wear parts: Tungsten is found in machines used as a wear part. This means that they are placed in machine parts that see a lot of wear and tear. However, its high wear resistance property does not allow it to wear.
- Knives: The use of Tungsten steel to make knives is genius. They do not get dull and cannot be damaged.
- Jewellery: Tungsten also has application in Jewelry making. They are used to make rings, earrings and necklaces.
Differences between Cemented Carbide and Tungsten Steel.
Tungsten Steel is an inorganic compound made up of tungsten and cobalt in a ratio of 80:20. This is why it is not “technically” referred to as a metal. However, it is referred to as a compound because it comprised of tungsten and cobalt. And in comparison, it is denser than titanium and steel. On the other hand, when we mention cemented carbide, we think of high-speed tools. Cemented carbide is used in high-speed machines because of its properties like its ability to withstand high temperatures. Cemented carbide also produces a better and durable finish on the materials it is used on. Cemented carbides consist of carbides of transition metals like Titanium, Vanadium, Chromium, Zirconium, Molybdenum, Niobium, Hafnium, Tantalum, and Tungsten). They are usually bound together or cemented using a soft metallic binder that consists of Ni, Co and Fe (or their alloys).
Tungsten steel is a result of the addition of tungsten to certain alloys to improve its chemical and mechanical characteristics. Tungsten steel is cemented carbide, but cemented carbide is not a tungsten steel. To shed more light on this, tungsten steel is made by adding 15-25% tungsten raw materials into molten steel through the steelmaking process. While cemented carbide is made by sintering tungsten carbide with cobalt or other metals with the use of powder metallurgy technology. Here, tungsten carbide is the main body with over 80% in content. The sintering process of tungsten steel starts by pressing the powder into the blank, followed by heating it into the sintering furnace to a certain sintering temperature, held at that temperature for a certain time and then cooling it down, in a bid to get the tungsten steel material with needed properties.
In simple words, all alloys with hardness more than HRC65 are referred to as cemented carbide. This automatically means that tungsten steel is cemented carbide; however, cemented carbide cannot be called tungsten steel.
Conclusion
Thank you for reading our article…we hope that it will help you understand the differences between tungsten steel and cemented carbide.