Content Menu
● Understanding Tungsten Carbide
● Applications of Tungsten Carbide
>> 1. Cutting Tools:
>> 2. Wear-Resistant Parts:
>> 3. Surgical Instruments:
>> 4. Ammunition:
>> 5. Other Applications:
● Techniques for Drilling Tungsten Carbide
>> 1. Diamond Tooling
>> 2. Electrical Discharge Machining (EDM)
>> 3. Abrasive Drilling
● Step-by-Step Guide to Drilling Tungsten Carbide with Diamond Hole Saw
>> 1. Preparation:
>> 2. Starting the Hole:
>> 3. Drilling Process:
>> 4. Completing the Hole:
>> 5. Inspection:
● Safety Precautions
● Conclusion
● FAQ
>> 1. What makes tungsten carbide so hard?
>> 2. Can I use regular drill bits to drill tungsten carbide?
>> 3. Why is it important to use a coolant when drilling tungsten carbide?
>> 4. What is the best speed for drilling tungsten carbide?
>> 5. Is EDM a better option than diamond drilling for tungsten carbide?
● Citations:
Tungsten carbide stands out as one of the toughest materials in the world, recognized for its exceptional hardness, strength, and resistance to wear and corrosion[3][4][6]. Composed of tungsten and carbon, it boasts a unique combination of properties that make it invaluable across various industries[2]. Its uses range from cutting tools and wear-resistant parts to surgical instruments and even ammunition[2][4][8].
Given its extreme hardness, drilling tungsten carbide presents a significant challenge[1][3]. Unlike softer materials, traditional drill bits typically fail against tungsten carbide due to the material's superior resistance to abrasion[1][3]. However, with the right techniques and tools, it is indeed possible to drill through tungsten carbide[1][5]. This article explores the methods, applications, and properties of tungsten carbide, offering a comprehensive guide to understanding and working with this remarkable material.
Understanding Tungsten Carbide
Tungsten carbide (WC) is a chemical compound comprising tungsten and carbon atoms[2]. Its molecular formula is WC, with a molecular weight of 195.85[2]. The compound is known for its exceptional physical and chemical properties, making it suitable for a wide array of applications[2].
- Hardness: Tungsten carbide has a microhardness of 17300 MPa, close to that of diamond, making it highly resistant to scratching and wear[2][6].
- Elastic Modulus: Its elastic modulus is 710GPa, indicating its stiffness and resistance to deformation under stress[2].
- Compressive Strength: The compressive strength is 56MP, showcasing its ability to withstand high pressure without breaking[2].
- Thermal Expansion: The coefficient of thermal expansion is 6.9 × 10-6 / K, meaning it expands minimally with temperature changes[2].
- Conductivity: Tungsten carbide is a good conductor of both electricity and heat[2][6].
- Chemical Resistance: It is insoluble in water, hydrochloric acid, and sulfuric acid, though it can be dissolved in a mixture of nitric and hydrofluoric acids[2].
- Oxidation Resistance: Tungsten carbide has a weak anti-oxidation ability, starting active oxidation in the air above 500°C[2].
Pure tungsten carbide is brittle, but its toughness can be improved by adding small amounts of other metals like titanium and cobalt[2]. These additives reduce brittleness and enhance the material's overall performance[2]. Tungsten carbide typically appears as a black hexagonal crystal with a metallic luster[2].
Applications of Tungsten Carbide
Tungsten carbide's unique properties make it indispensable in numerous applications across various industries[2][4][6].
1. Cutting Tools:
- Tungsten carbide is extensively used in manufacturing cutting tools such as drills, milling cutters, taps, cutting wheels, and saw blades[2][9].
- Its high hardness and wear resistance enable these tools to cut through difficult materials like steel, titanium, and other carbides[8][9].
- Carbide cutting surfaces are essential for machining tough materials like carbon steel and stainless steel, especially in high-quantity and high-precision production[8].
- They maintain a sharp cutting edge longer than steel tools, resulting in better finishes and faster machining[8].
- Coatings such as titanium aluminum nitride or titanium chromium nitride can further enhance thermal stability and prolong tool life[8].
2. Wear-Resistant Parts:
- It is used to make parts subjected to high stresses, such as those in the oil and gas, mining, and pulp and paper industries[2][9].
- These parts benefit from high wear resistance, corrosion resistance, and extended lifespan[9].
3. Surgical Instruments:
- Tungsten carbide enhances the performance of surgical instruments due to its corrosion resistance and durability[4].
- Its ability to maintain a sharp edge is crucial for precise surgical procedures[4].
4. Ammunition:
- Tungsten carbide is used in armor-piercing ammunition due to its hardness and high density[8].
- It is particularly effective in sabot rounds, where a plastic sabot discards at the barrel muzzle, allowing the projectile to penetrate armor effectively[8].
5. Other Applications:
- Kiln Furnace Structural Materials: Used in high-temperature environments due to its heat resistance[2].
- Jet Engine Components: Ensures durability and reliability in extreme conditions[2].
- Cermet Materials: Enhances the properties of composite materials[2].
- Resistance Heating Elements: Provides efficient heat generation[2].
- Smelting Crucibles: Suitable for metals such as copper, cobalt, and bismuth[2].
- Semiconductor Films: Offers wear resistance in semiconductor manufacturing[2].
- Sports Equipment: Used in golf clubs and ski poles for added durability[4][6].
- Musical Instruments: Utilized in guitar slides for their smooth and durable surface[4].
- Ballpoint Pens: Forms the tip of ballpoint pens due to its wear resistance[4].
- Space Satellites: Provides resistance to extreme temperature fluctuations[4].
- Injection Molding Tools: Precision molds for plastic injection molding benefit from tungsten carbide's high precision, durability, and wear resistance[9].
Techniques for Drilling Tungsten Carbide
Drilling tungsten carbide requires specialized techniques and tools due to its extreme hardness[1][3]. Traditional drill bits made of high-speed steel (HSS) are generally ineffective[1][3]. The primary methods for drilling tungsten carbide include using diamond tools and electrical discharge machining (EDM)[1][7].
1. Diamond Tooling
Diamond, being one of the hardest materials, is an ideal choice for drilling tungsten carbide[1][7]. Diamond tools come in various forms, including diamond-coated hole saws, diamond core drills, and PCD (polycrystalline diamond) twist drills[1][5][7].
Diamond-Coated Hole Saws:
- These are effective for creating larger holes in tungsten carbide[1][3].
- The hole saw features a circular blade with diamond particles embedded in the cutting edge[1].
- It is crucial to use a coolant, such as water, to keep the drill bit cool and reduce friction[1].
- Start drilling at an angle to allow the bit to bite into the material before straightening the drill[1].
- Applying steady pressure and maintaining a slow, consistent speed are essential for achieving a clean hole[1].
Diamond Core Drills:
- Diamond core drills are suitable for creating precise holes[7].
- These drills have a hollow core with diamond particles on the cutting edge[7].
- They are often used with a water feed spindle to keep the drilling area cool and flush away debris[7].
PCD Twist Drills:
- PCD twist drills are designed specifically for drilling hard materials like tungsten carbide[5].
- The polycrystalline diamond structure provides excellent wear resistance and cutting performance[5].
- These drills can create smaller holes with high precision[5].
2. Electrical Discharge Machining (EDM)
EDM is a non-traditional machining process that uses electrical sparks to erode the material[7]. It is particularly useful for creating complex shapes and holes in hard materials like tungsten carbide[7].
Process:
- EDM involves creating a series of rapidly recurring current discharges between two electrodes, separated by a dielectric fluid[7].
- One electrode is the cutting tool, and the other is the tungsten carbide workpiece[7].
- The sparks erode the material, gradually creating the desired shape or hole[7].
Advantages:
- EDM can create intricate shapes and very small holes[7].
- It does not require direct contact between the tool and the workpiece, reducing the risk of mechanical stress and damage[7].
Disadvantages:
- EDM is a relatively slow process compared to other machining methods[7].
- It requires specialized equipment and expertise[7].
3. Abrasive Drilling
Abrasive drilling involves using abrasive particles, such as diamond dust, mixed with a fluid to erode the tungsten carbide[7].
Process:
- A copper tube is used as the drill bit, and diamond dust is mixed with oil or water to form a slurry[7].
- The slurry is fed into the drilling area as the drill rotates, gradually eroding the material[7].
Advantages:
- This method can be used with relatively simple equipment[7].
Disadvantages:
- Abrasive drilling is a slow and labor-intensive process[7].
- It may not produce highly precise holes[7].
Step-by-Step Guide to Drilling Tungsten Carbide with Diamond Hole Saw
Here's a step-by-step guide on how to drill tungsten carbide using a diamond-coated hole saw[1]:
Materials and Tools Needed:
- Tungsten carbide workpiece[1]
- JCB diamond tech hole saw (or similar diamond-coated hole saw)[1]
- Drill[1]
- Clamp[1]
- Piece of wood (for securing the workpiece)[1]
- Tray with water (for cooling the drill bit)[1]
- Safety glasses and gloves[1]
1. Preparation:
- Secure the tungsten carbide workpiece to a piece of wood using a clamp[1]. This prevents the material from moving during drilling, ensuring accuracy and safety[1].
- Ensure you have a tray of clean, cold water nearby to cool the drill bit[1].
2. Starting the Hole:
- Begin drilling at a slight angle to allow the hole saw to bite into the tungsten carbide[1].
- Apply gentle, consistent pressure[1].
- Once the bit has gained a foothold, gradually straighten the drill[1].
3. Drilling Process:
- Maintain a slow and steady speed throughout the drilling process[1].
- Apply consistent pressure, but avoid forcing the drill[1].
- Every five seconds, remove the drill bit and cool it in the tray of water[1]. This prevents overheating, which can damage the diamond coating and reduce the bit's lifespan[1].
4. Completing the Hole:
- Continue drilling until you have cut all the way through the tungsten carbide[1].
- Once the hole is complete, carefully remove the core from the hole saw[1].
5. Inspection:
- Inspect the drilled hole for any imperfections[1].
- Check the condition of the drill bit to ensure it is still in good working order[1].
Safety Precautions
When working with tungsten carbide and power tools, it is crucial to follow safety precautions to prevent injuries[1].
- Wear Safety Glasses: Always wear safety glasses to protect your eyes from flying debris[1].
- Use Gloves: Wear gloves to protect your hands from sharp edges and potential cuts[1].
- Coolant Use: Use a coolant, such as water, to keep the drill bit and workpiece cool[1]. This prevents overheating and extends the life of the tool[1].
- Secure Workpiece: Ensure the workpiece is securely clamped to prevent movement during drilling[1].
- Avoid Overheating: Do not allow the drill bit to overheat. Cool it regularly to maintain its effectiveness and prevent damage[1].
- Consistent Pressure: Apply consistent pressure while drilling, but avoid forcing the tool[1].
- Proper Ventilation: Work in a well-ventilated area to avoid inhaling dust or fumes[1].
- Tool Maintenance: Regularly inspect and maintain your tools to ensure they are in good working condition[1].
Conclusion
Drilling tungsten carbide, while challenging, is achievable with the right tools and techniques. Diamond-coated hole saws, diamond core drills, and PCD twist drills are effective for creating holes in tungsten carbide[1][5][7]. Electrical discharge machining (EDM) offers an alternative for complex shapes and small holes[7]. By following the recommended procedures and safety precautions, you can successfully work with this exceptionally hard material[1]. Tungsten carbide's unique properties make it essential in numerous applications, and understanding how to machine it expands its utility even further[2][4][6].
FAQ
1. What makes tungsten carbide so hard?
Tungsten carbide's hardness comes from the strong covalent bonds between tungsten and carbon atoms[2]. This creates a dense, rigid structure that resists deformation and wear[2]. The addition of metals like cobalt further enhances its toughness and reduces brittleness[2].
2. Can I use regular drill bits to drill tungsten carbide?
No, regular drill bits made of high-speed steel (HSS) are not effective for drilling tungsten carbide[1][3]. Tungsten carbide is much harder than HSS, causing the drill bit to wear down quickly without making significant progress[1][3]. Diamond-coated or PCD drills are necessary[1][5].
3. Why is it important to use a coolant when drilling tungsten carbide?
Using a coolant, such as water, is crucial to dissipate heat generated during the drilling process[1]. Overheating can damage the diamond coating on the drill bit, reducing its effectiveness and lifespan[1]. Additionally, coolant helps to flush away debris, preventing it from clogging the cutting area[1].
4. What is the best speed for drilling tungsten carbide?
The best speed for drilling tungsten carbide is typically slow and steady[1]. High speeds can generate excessive heat and cause the drill bit to wear out quickly[1]. A slow, consistent speed allows the diamond particles to effectively grind away the material without overheating[1].
5. Is EDM a better option than diamond drilling for tungsten carbide?
EDM can be a better option for creating complex shapes, very small holes, or when precision is paramount[7]. However, EDM is a slower and more expensive process compared to diamond drilling[7]. Diamond drilling is suitable for simpler holes and when speed and cost-effectiveness are important factors[1][7].
Citations:
[1] https://www.youtube.com/watch?v=xJIPeNA1Iyw
[2] https://www.refractorymetal.org/tungsten-carbide-uses-properties.html
[3] https://www.ultimatehandyman.co.uk/video/how-to-drill-a-hole-through-tungsten-carbide_966acd090.html
[4] https://www.tungco.com/insights/blog/5-tungsten-carbide-applications/
[5] https://www.youtube.com/watch?v=6bB6mixjHn8
[6] https://www.carbide-usa.com/top-5-uses-for-tungsten-carbide/
[7] https://www.cnczone.com/forums/hard-high-speed-machining/7944-drilling-carbide.html
[8] https://en.wikipedia.org/wiki/Tungsten_carbide
[9] https://www.sollex.se/en/blog/post/about-cemented-tungsten-carbide-applications-part-1
