High-speed steel（HSS） and Tungsten carbide are two important tool materials, both widely used in manufacturing cutting tools. HSS is an alloy steel with added carbide-forming elements and can attain hardness above HRC 60 after quenching. Tungsten carbide is a ceramic-like material composed of Tungsten steel particles bonded together by cobalt. In comparison, Tungsten steel has higher hardness, strength, and wear resistance.What follows is which is better ,HSS or Carbide(HSS vs Carbide).
hSS vs carbide—–HSS
HSS is a type of tool steel that possesses high hardness, high wear resistance, and high heat resistance. It is also called air-hardening steel or air-quenching steel, meaning that it can harden by just cooling in air after quenching, and becomes very sharp. It is sometimes called white steel as well.
HSS is a complex alloy steel containing carbide-forming elements like tungsten, molybdenum, chromium, vanadium, and cobalt. The total alloying content is around 10-25%. It can still maintain high hardness (above HRC 60) at high temperatures generated during high-speed cutting (around 500°C). This is the most important property of high-speed steel – red hardness. While carbon tool steels can attain very high hardness after quenching and low-temperature tempering, their hardness decreases rapidly above 200°C, and at 500°C the hardness drops to a level similar to the annealed state, completely losing the ability to cut metals. This limits the use of carbon tool steel for cutting tools. High-speed steel makes up for this fatal weakness of carbon tool steels owing to its good red hardness.
HSS is mainly used to manufacture complex thin-blade tools and impact-resistant metal cutting tools. It can also be used to make high-temperature bearings and cold extrusion molds. Typical applications include lathe tools, drills, hobs, hacksaw blades, and high-performance molds.
HSS vs carbide—–Tungsten carbide
Tungsten carbide possesses a series of excellent properties including high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance. Its high hardness and wear resistance remain almost unchanged even at 500°C, and it still has very high hardness at 1000°C.
Tungsten carbide, with Tungsten steel and cobalt as the main components accounting for 99% of all constituents, and the remaining 1% being other metals, is therefore also called tungsten carbide or cemented carbide and is considered the teeth of modern industry.
Tungsten carbide is a sintered composite material composed of at least one metal carbide. Common ingredients of tungsten carbide include Tungsten steel, cobalt carbide, niobium carbide, titanium carbide, and tantalum carbide. The grain size of the carbide ingredients (or phases) is usually between 0.2-10 microns. The carbide grains are bonded together by a metal binder which is generally iron group metals, commonly cobalt and nickel. Thus there are tungsten-cobalt alloys, tungsten-nickel alloys, and tungsten-titanium-cobalt alloys. Sintering of tungsten steel involves compressing the powders into a compact, and then heating them to a certain temperature (sintering temperature) in a sintering furnace and holding them for a period of time (holding time), before cooling down to obtain tungsten carbide material with desired properties.
1. Tungsten-cobalt cemented carbides
The main ingredients are Tungsten steel (WC) and cobalt (Co) binder. Their grades are designated by “YG” (the initials of “Ying”, meaning hard, and “Gong”, meaning cobalt in Chinese pinyin) plus the average cobalt content in percentage. For example, YG8 indicates a tungsten-cobalt cemented carbide with average WCo=8% and the remainder being Tungsten caibide.
2. Tungsten-titanium-cobalt cemented carbides
The main ingredients are Tungsten steel, titanium carbide (TiC), and cobalt. Their grades are designated by “YT” (the initials of “Ying” for hard and “Ti” for titanium in Chinese pinyin) plus the average titanium carbide content. For example, YT15 indicates a tungsten-titanium-cobalt cemented carbide with an average TiC=15%, and the remainder being Tungsten steel and cobalt.
3. Tungsten-titanium-tantalum/niobium cemented carbides
The main ingredients are Tungsten steel, titanium carbide, tantalum/niobium carbide, and cobalt. This type of cemented carbide is also known as universal cemented carbide. Their grades are designated by “YW” (the initials of “Ying” for hard and “Wan” for universal in Chinese pinyin) plus a serial number, such as YW1.
Tungsten carbide possesses excellent properties including high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance. Its high hardness and wear resistance remain almost unchanged even at 500°C, and it still has very high hardness at 1000°C. Cemented carbides are widely used as tool materials, such as lathe tools, milling cutters, drills, reamers, etc. The cutting speed of new cemented carbides can be hundreds of times that of carbon steels.
What are the differences between HSS and Tungsten carbide?
HSS mainly consists of iron with added carbide-forming alloy elements, while Tungsten carbide mainly consists of Tungsten carbide particles bonded by cobalt. High-speed steel has excellent hot hardness and Tungsten carbide has higher hardness and wear resistance.
What are the different application areas of HSS and Tungsten carbide?
HSS is often used to make cutting tools like drills, end mills, etc. Tungsten carbide is often used for tools in continuous and interrupted cutting like turning, milling, reaming, etc.
What are the pros and cons of HSS and Tungsten carbide respectively?
The pros of HSS are low cost and good machinability; the cons are poorer hardness and wear resistance. The pros of Tungsten carbide are high hardness and wear resistance; the cons are high cost and brittleness.
How do the cutting speeds of HSS and Tungsten carbide compare in machining?
Under the same cutting conditions, Tungsten carbide can have 3-5 times the cutting speed of high-speed steel.
What is the difference in tool life between HSS and Tungsten carbide tools?
Under the same cutting conditions, Tungsten carbide tools can have several times to tens of times more tool life compared to high-speed steel tools.
conclusion
Therefore, HSS and Tungsten carbide have their own application areas. HSS is commonly used to make drills, end mills, etc., while Tungsten carbide is used for turning tools, boring bars, and other applications requiring high hardness and wear resistance. The two materials can be optimized based on actual needs, leveraging their respective strengths to improve overall cutting tool performance.
