новости компании о What Is Cemented Carbide?

If you work in manufacturing, mining, or tooling, you’ve likely heard the term “cemented carbide” – but what exactly is it? Is it the same as tungsten carbide? And why is it so widely used in tough industrial jobs? Cemented carbide (often called “hard metal”) is a composite material made by bonding hard ceramic particles (like tungsten carbide) with a soft metal binder (like cobalt or nickel) through high heat and pressure. It combines the extreme hardness of ceramic particles with the toughness of the metal binder, making it one of the most durable materials for wear-resistant and cutting applications. In this article, we’ll break down its composition, how it’s made, key properties, common types, and real-world uses. All content is simplified for clarity, with practical examples that industrial professionals can relate to.

Cemented carbide’s performance comes from its two main components – “hard phase” particles and a “binder phase” metal. These work together to balance hardness and toughness, which no single material (like pure metal or ceramic) can do alone.

Note: Tungsten carbide (WC) is the most popular hard phase – over 90% of industrial cemented carbide products use WC as the main hard component. This is why “cemented carbide” is often colloquially called “tungsten carbide” (though technically, tungsten carbide is just one part of the composite).

Cemented carbide isn’t cast or forged like metal – it’s made using powder metallurgy, a process that turns fine powders into a dense, solid material. The steps are straightforward and tightly controlled to ensure quality:

1. Powder Preparation:

   • The hard phase (e.g., WC) and binder (e.g., Co) are ground into ultra-fine powders (particle size: 0.5–10 micrometers, about 1/20 the width of a human hair).
   • Powders are dried to remove moisture (moisture causes pores in the final product) and sieved to remove clumps.

2. Powder Mixing:

   • Powders are mixed in precise ratios (e.g., 94% WC + 6% Co) using ball mills. A liquid (like alcohol) or lubricant (like wax) is added to ensure even distribution of the binder around the hard particles.
   • Mixing takes 4–24 hours – uniformity here is critical: uneven binder distribution leads to weak spots in the final product.

3. Compaction:

   • The mixed powder is pressed into a “green compact” (rough shape of the final product) using hydraulic presses. Pressure ranges from 150–600 MPa (1,500–6,000 times atmospheric pressure) to pack the powder tightly.
   • The green compact is fragile (like a dried sandcastle) but holds its shape – it’s now ready for sintering.

4. Sintering (The “Hardening” Step):

   • The green compact is placed in a furnace and heated to 1,300–1,600°C (2,372–2,912°F) in a protective atmosphere (argon or nitrogen, to prevent oxidation).
   • At high temperatures, the binder metal melts and flows around the hard phase particles, “gluing” them together. The compact shrinks by 5–20% as gaps between powders close.
   • The furnace cools slowly (2–5°C per minute) to avoid cracking – this step turns the fragile compact into a dense, hard cemented carbide part.

5. Post-Processing (Optional):

   • For precision parts (e.g., cutting tools, seal rings), the sintered part is ground with diamond wheels (since cemented carbide is harder than steel) to refine size and shape.
   • Some parts are polished or coated (e.g., titanium nitride, TiN) to boost wear resistance or reduce friction.

Cemented carbide’s popularity comes from four unbeatable properties that make it ideal for harsh industrial conditions:

• Hardness: 8.5–9 on the Mohs Hardness Scale (only diamond, cubic boron nitride, and a few others are harder).
• Wear resistance: Lasts 5–10 times longer than high-carbon steel in wear-heavy jobs. For example, a cemented carbide mining liner can handle gritty ore for 6–24 months, while a steel liner lasts just 1–3 months.

• Unlike pure ceramic (which shatters on impact), the metal binder makes cemented carbide tough enough to withstand shocks. A cemented carbide drill bit can hit a hard rock without breaking, while a ceramic bit would crack immediately.

• It retains hardness at high temperatures (up to 500–800°C, 932–1,472°F, depending on the binder). This makes it perfect for cutting tools – when machining metal, the tool tip gets hot, but cemented carbide doesn’t soften or lose its edge.

• Resists rust, corrosion, and chemical attack (especially nickel-bonded cemented carbide). It works in seawater (e.g., pump seals) or chemical plants (e.g., valve parts) without degrading.

Not all cemented carbide is the same – the ratio of hard phase to binder, and the type of hard phase, are adjusted for specific jobs. Here are the most common types used in industry:

Cemented carbide is everywhere in heavy industry – if a part needs to be hard, tough, or wear-resistant, it’s likely made of cemented carbide. Here are the most common uses:

• The biggest application: Drill bits, lathe tools, milling inserts, and saw blades for machining metal, wood, or concrete. A cemented carbide cutting insert can machine thousands of metal parts before needing replacement.

• Wear parts like crusher teeth, conveyor belt scrapers, and mining drill bits. These parts handle abrasive ore and rocks – cemented carbide’s wear resistance cuts down on replacement costs.

• Seal rings for pumps (prevent leaks and resist wear), bearing bushes (reduce friction in heavy machinery), and extrusion dies (shape metal or plastic without wearing out).

• Small, high-precision parts like nozzles (for 3D printing or fuel injection), watch gears (hard and scratch-resistant), and medical tools (e.g., dental drills, which need to be hard and sterile).

1. Myth: “Cemented carbide is the same as tungsten carbide.”
   Fact: Tungsten carbide (WC) is just the hard phase in most cemented carbide. Cemented carbide is a composite – it needs a binder (like cobalt) to hold the WC particles together. Think of it like a cookie: WC is the chocolate chips, and cobalt is the dough.

2. Myth: “Cemented carbide is too expensive to use.”
   Fact: While it costs more upfront than steel, it lasts 5–10 times longer. For example, a $50 cemented carbide drill bit lasts 10x longer than a $10 steel bit – over time, it’s cheaper because you replace it less often.

Cemented carbide’s unique mix of hardness, toughness, and heat resistance makes it irreplaceable in tough industrial jobs. Whether you’re machining metal, mining ore, or building pumps, it’s the material that keeps equipment running longer and more reliably.

The key to getting the most out of cemented carbide is choosing the right type for your application: WC-Co for versatility, WC-Ni for corrosion resistance, and WC-TiTaC-Co for high-speed machining.

If you’re unsure which cemented carbide type is best for your project (e.g., a new cutting tool or wear part), feel free to reach out. We can help match the material to your needs and budget.