How Cryogenic Processing Makes Carbide End Mills Better
- October 29, 2020
- Controlled Thermal Processing
- Cryogenic Treatment
There’s a great demand for robust cutting and milling tools. They’re widely used in industrial applications and there’s always a need for improving the durability of these tools. Given the sheer stress and temperatures that they withstand day in and day out, these tools tend to wear out pretty quickly.
That’s why there’s a need for improving the durability and increasing the lifespan of these tools. Companies that utilize them will be able to get more mileage out of their tools before having to replace them. Imagine squeezing additional life out of a tool that’s used in large quantities by a business? The cost savings can add up pretty quickly.
What are carbide end mills?
An end mill is a kind of milling cutter that’s used for industrial milling and cutting applications. To some, it may look like a drill bit but it’s actually different in its form and function.
A drill bit is only capable of cutting in the axial direction while most milling bits are able to cut in the radial direction. However, not all of them can cut axially. This is where end mills stand out because the mills that can cut axially are called end mills.
Carbide end mills have a matrix made up of tungsten carbide that’s held together by a binder that’s usually cobalt. They may also have a very thin end mill coating in order to further improve the cutting performance. It’s primarily the tungsten carbide that does the heavy lifting here, though.
How cryogenic treatment improves carbide end mills and other tools
Cryogenic processing is an effective method of improving the durability of carbide cutting tools. It does that by enhancing the resiliency of the cobalt alloy binding which holds the carbide composite tools together. The result is a significant increase in the tool life and durability.
What is cryogenic treatment?
At its core, cryogenic hardening or processing is the modification of a material or tool using cryogenic temperatures. It’s fundamentally different from cold treatments that only go down to temperatures of -140ºF.
Cryogenic temperatures range from −238 °F to −460 °F. Only when these temperatures are reached can the process of cryogenic treatment begin.
This process achieves increased durability for metals because it fundamentally changes their crystalline lattice. This lattice is set by the alloys in the metal and it also depends on the way it’s processed, cast, forged, and treated. Regardless of the production process the metal goes through, there are almost always imperfections in the final product.
These imperfections can create weaknesses in the material that won’t even be visible to the naked eye. Through deep cryogenic treatment, the temperature of metals is dropped to as low as -450℉. This is done to achieve the theoretical correct distance between the atoms in the lattice. This forces the imperfections to correct themselves.
Other carbide tools cryogenic treatment improves
The cryogenic treatment process isn’t useful for just carbide end mills. Other tools can be put through the same process to achieve similar results. This includes the likes of carbide drills in single or multiple diameter and margin, solid or coolant through with a helical or straight flute.
Carbide reamers are another tool that stand to benefit from cryogenic treatment. These can have straight, tapered or step designs, can be solid or coolant through with a helical or straight flute. Since they’re made of metal as well, the process will work just as well on these. The same holds true for carbide porting tools and form tools.
Comparing carbide end mills before and after deep cryogenic processing
Research has revealed that deep cryogenic treatment can significantly alter the microstructure of tungsten carbide. This causes the beta-phase particles to increase in both size and quantity. A corresponding decrease is also shown in the eta-phase and y-phase particles.
A clear difference can be seen in the performance of carbide end mills before and after deep cryogenic treatment. Our research has shown that after processing, the hardness of these cutting tools can increase by nearly 7%.
It’s important to take the proper precautions after the treatment since keeping the carbide cool is essential to maintaining the wear resistance that’s created by the treatment.
Similar tests on treated and untreated carbide inserts have shown how both respond to wear and tear over time. When milling both inserts on the same cutter, significant wear can be seen at the area near the top of the untreated insert compared to the one that went through deep cryogenic treatment.
Other research on cryogenic processing and metal hardening
Researchers have studied the effects of cryogenic treatment on the toughness and tribological behaviors of eutectoid steel.
In this research, a high speed train railway material was investigated with different hardening processes applied to the steel. The effects of cryogenic treatment were investigated on the mechanical properties of the steel.
The subsequent testing showed that the cryogenic treatment improved the toughness and hardness of quenched samples.
The results of the ball-on-disc wear tests also showed that samples which were treated cryogenically showed better wear resistance than the pearlitic and martensitic samples.
Another study looked at the effect of cryogenic treatment of the cutting tool on surface roughness in machining of stainless steel.
Tungsten carbide tools are commonly used for machining stainless steel. The research was conducted to see the surface roughness of the work specimen during the turning operation.
The machining was done with deep and shallow cryogenically treated and untreated tool bits that were used in the turning process. The results showed that materials with cryogenic treatment had improved hardness.
CTP Cryogenics is the leader in deep cryogenic treatment
Deep cryogenic processing is a more advanced method that requires the temperature of metals and materials to be brought down to temperatures below -300⁰F slowly. This is done to modify the crystalline structure in order to make it more uniform and durable. These changes then become permanent when the material is gradually brought back up to room temperature.
It’s a very specialized process that requires in-depth knowledge and state of the art equipment.
The materials have to be submerged in cryogenic materials for up to 24 hours. Many different variables also need to be managed during the process to make sure that the treatment is effective.
Deep cryogenic treatment is something that Controller Thermal Processing Cryogenics is an expert in. We have almost four decades of experience in this field and are among the leaders in the cryogenic processing industry.
We use our proprietary processes to help customers improve the quality and increase the lifespan of everything from tools and dies to brake rotors and boat propellers.
Our business utilizes the most advanced research and technology in cryogenics to provide results unlike any other company.
CTP continues to conduct extensive research in the field of cryogenics to further advance the technology. We offer our services coast to coast in the United States from our three locations.
The services that we offer include processing of metal parts for all industries and applications, metallurgical advising, micropolishing, cryogenic processing with liquid helium, and sales of specialized cryogenic treatment equipment.
Need any assistance or have a project that you’d like us to jump right in to? Contact us today for a free quote and our team will be happy to assist you.