There are several different materials used to make cutting tools like drill bits, inserts, and milling cutters. These materials have different properties that suit them to different applications. The cutting tool material must be harder than the workpiece material and remain so at the high temperatures generated by high-speed machining. These requirements have led to the development of advanced tooling materials like tungsten carbide that have largely replaced carbon steel tooling, although carbon steel tooling is still used in many cutting applications.
Currently, tungsten carbide is the most commonly used machining tool material, but other materials and coatings are also frequently utilized. When it comes to recycling scrap metal tooling, it’s very useful to be able to distinguish between tungsten carbide, steel, and other materials, as some are recyclable and some are not. Some materials are much more valuable than others as well.
In this post, we’ll look at the differences between tungsten carbide vs. steel and other tooling as well as how to differentiate between them when recycling waste metal tooling.
High-speed steel (HSS) is a high-carbon tool steel that usually contains tungsten and other hard alloying elements. It has high hardness, wear resistance, and heat resistance. As a type of steel, HSS is very strong and can withstand high cutting forces without breaking. It is also the cheapest material for cutting tools.
HSS performs well in intermittent cutting applications, but its maximum cutting speed is far lower than more advanced materials like tungsten carbide. Tungsten carbide tools and inserts have almost completely replaced HSS in most cutting applications. However, HSS is still a popular material for drill bits, as they are less likely to break, especially when drilling deep, small-diameter holes.
Tungsten carbide is a versatile, durable chemical compound of tungsten and carbon. In tooling, it is combined with cobalt to form a composite material with excellent hardness, wear resistance, strength, toughness, and heat resistance. Its high hardness and wear resistance are stable at higher temperatures than steel, allowing for faster cutting speeds than steel tooling.
Carbide tooling can be improved even further by adding coatings like titanium nitride (TiN). Some of the benefits of TiN-coated cutting tools include:
- High chemical inertness.
- Improved temperature resistance.
- Reduced friction and tool wear.
- Longer tool life.
Polycrystalline diamond is another composite material that consists of diamond particles sintered together with a metallic binder. Diamond is extremely hard—even harder than tungsten carbide—making it an excellent material for cutting tool edges. Some advantages of polycrystalline diamond as a tooling material include:
- Extreme hardness.
- Low friction and high wear resistance.
- Greater cut duration.
- Optimal finish quality.
Differences Between Tungsten Carbide vs. Steel
There are fundamental differences in the chemistries of tungsten carbide vs. steel. While steel is a metal, tungsten carbide is a ceramic material. Tungsten carbide is harder but more brittle than steel, so it can crack or shatter from a strong enough impact.
Tungsten carbide tools are more expensive than steel but are usually more valuable in the long run because they last much longer. Tungsten carbide maintains a sharp cutting edge longer than steel, produces a better finish, and can cut harder materials. It can also withstand higher temperatures and therefore faster cutting speeds than steel.
Tungsten carbide cutting tools have several advantages, including:
- A long-lasting cutting edge.
- The ability to withstand the high temperatures generated by high cutting speeds.
- A long working life.
- High-quality surface finish capabilities.
Distinguishing Between Tungsten Carbide vs. Steel Tooling
Identifying tungsten carbide vs. steel tooling can often be done visually. Steel tools are usually forged from a single piece of steel, with the tip hardened by heat treatment. Tungsten carbide tools typically consist of a steel body with a tungsten carbide insert. Tungsten carbide is darker than steel, and the joint between the carbide insert and the steel tool body is usually visible, making carbide tools easy to recognize. When these tools fail, it is usually either along this joint or by breaking the tip. However, some small milling cutters are machined from a single piece of tungsten carbide, so the joint line may not always be present.
Fortunately, there are other ways to distinguish between tungsten carbide and steel. First of all, tungsten carbide is approximately twice as dense as steel. Comparing the weights of solid tungsten carbide and steel can quickly tell you which one you have.
Another major difference between tungsten carbide and steel is their magnetism. If you test a piece of tungsten carbide with a magnet, there should be very little attraction. If the magnet is hard to pull away from the tool, it’s steel.
Finally, tungsten carbide and steel spark differently when cutting. If you put them on a grinding wheel, tungsten carbide sparks are closer together and more orange in color than steel sparks.
What about coated tools? TiN-coated tools are easy to recognize by their metallic gold color; however, TiN coatings are applied to both steel and carbide tools, so you may not be able to easily identify the underlying material of intact TiN-coated tools.
Recycle Tungsten Carbide Tooling with a Reliable Local Metal Recycler
Industrial Metal Service has been providing San Francisco Bay Area industries with fair and honest metal recycling services for more than two decades. We recycle tungsten carbide tooling and inserts, with no minimums on how much can be recycled at a time. These spent tools can return significant value to your company.