Carbide grades are crucial in machining, directly influencing tool performance, efficiency, and longevity across various manufacturing industries. Selecting the correct grade for a given application means choosing a grade with an optimal balance of hardness and toughness. As machining technologies advance, understanding the production process, composition, and classifications of carbide grades becomes increasingly crucial for businesses aiming to stay competitive and meet challenging application requirements.
What Is a Carbide Substrate?
A substrate is the base carbide material of the solid tool or cutting insert beneath any coatings and post-treatments. It consists of 80-95% tungsten carbide (WC), a tungsten and carbon compound.
Finding the right balance between toughness and hardness is the most critical factor when selecting a grade for a certain application. A grade that is too hard can lead to micro-breaks along the cutting edge, while a grade that is too tough may wear out quickly and reduce productivity. The ideal levels of toughness and hardness optimize tool performance and service life.
What Are Carbide Coatings?
Carbide coatings protect cutting tools and enhance their performance. These thin films, typically 3 to 20 microns thick, are composed of materials such as aluminum oxide (Al2O3), titanium nitride (TiN), and/or titanium carbon nitride (TiCN). Coatings increase surface hardness, create a heat barrier between the substrate and the workpiece, and enhance wear resistance.
There are two ways coatings are applied, PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition). When coatings are applied to milling inserts and cutting tools, generally, PVD’s hardness improves wear resistance and tool life. Whereas CVD coatings withstand higher cutting temperatures and may allow for lower cutting forces.
What Are the Different Grades of Carbide?
Selecting the appropriate carbide grade involves evaluating application requirements and consulting supplier catalogs or charts. Although no universal standard exists, most suppliers specify an application range expressed in a three-character combination of letters and numbers (e.g., P05-P20). Here’s what each character and number represents:
- Material group (ISO standard). The first letter represents the ISO material group, each of which is assigned a corresponding color for easy identification.
- Hardness level. The following two numbers indicate the grade’s relative hardness on a scale from 05 to 45. Lower numbers denote applications that need very hard grades for stable, favorable conditions. Higher numbers indicate applications that need very tough grades for unstable, unfavorable conditions.
It’s important to note that grades with the same range for different applications may exhibit varying hardness levels. For instance, a P10-P20 turning grade may differ in hardness compared to a P10-P20 milling grade due to the differences in what constitutes “favorable conditions” for each process. Turning benefits more from harder carbide grades, while the frequent interruptions of milling benefit more from tougher grades.
ANSI and ISO Standards
Carbide grades must adhere to certain ANSI and ISO standards to facilitate selection and proper application. Ultra-Met offers grades that comply with both ANSI and ISO classification systems:
- ANSI C-system. This system categorizes grades from C1 to C8, offering a range of options for different applications. These grades are widely used in North America and indicate the balance between wear resistance and toughness.
- ISO classification. Grades fall under P, M, and K categories, each followed by a number describing specific material qualities. The inclusion of titanium, tungsten, or tantalum influences carbide properties within these classifications. The ISO system is globally recognized and helps manufacturers select appropriate grades based on application demands and machining environments.
All of our carbide grades have a “C” classification for the ANSI code, or a “P” or “K” label for the ISO standard. For a detailed breakdown of our product offerings, refer to these carbide grade charts:
Contact Ultra-Met For Help Choosing the Right Carbide Grade
Understanding the composition and classification of carbide grades will help you make informed choices that enhance machining efficiency and tool longevity. Since 1965, Ultra-Met has been supplying high-quality carbide blanks to fabricators and toolmakers across diverse industries, including aerospace, automotive, energy, and medical. For expert guidance in selecting the best carbide grades for your specific needs, contact us today or request a quote.