Choose the Right Carbide Grade for Your CNC Turning Application Selecting the correct carbide grade is just as important as choosing the insert geometry. Different workpiece materials, cutting conditions, and machining strategies require different combinations of hardness, toughness, wear resistance, and coating technology. Zhuzhou Century Tool offers a complete range of carbide grades optimized for steel, stainless steel, cast iron, and difficult-to-machine alloys. Carbide Grade Comparison Grade ISO Material Recommended Application Features CT2525 P General steel turning Excellent balance between wear resistance and toughness for most machining operations CT3525 P Heavy roughing High impact resistance for interrupted cutting and heavy feed rates CT1525 P Finishing Higher hardness delivers excellent surface finish and dimensional accuracy CT3015 M Stainless steel Superior toughness with improved resistance to built-up edge and chipping CT4015 K Cast iron Outstanding abrasion resistance and thermal stability CT6020 S Heat-resistant alloys Designed for nickel-based and high-temperature alloys CT7020 H Hardened steel High hardness and wear resistance for hardened materials up to HRC60 Grade Details CT2525 – Universal Steel Grade Best for Medium turning General machining Semi-finishing Light roughing Suitable Materials Carbon steel Alloy steel Forged steel Advantages Long tool life Stable cutting Excellent chip control Most popular universal grade Recommended Cutting Continuous cutting Moderate speed General CNC production CT3525 – Heavy Cutting Grade Designed for maximum toughness under demanding cutting conditions. Best Applications Heavy roughing Interrupted cutting Forgings Scale-covered materials Advantages Extremely high fracture resistance Excellent edge strength Stable under heavy loads Suitable for large depth of cut CT1525 – Finishing Grade Optimized for precision machining where surface quality is critical. Best Applications Finish turning High-speed machining Precision components Advantages Higher hardness Better wear resistance Excellent surface finish Longer life at high cutting speeds CT3015 – Stainless Steel Grade Specially developed for machining stainless steels. Suitable Materials 304 316 Duplex stainless steel Austenitic stainless steel Advantages Excellent resistance to built-up edge Improved toughness Better chip evacuation Stable edge integrity Grade Selection by Workpiece Material Workpiece Material Recommended Grade Carbon Steel CT2525 Alloy Steel CT2525 / CT3525 Forged Steel CT3525 Stainless Steel CT3015 Cast Iron CT4015 Heat Resistant Alloy CT6020 Hardened Steel CT7020 Grade Selection by Machining Operation Machining Type Recommended Grade Finishing CT1525 Semi-Finishing CT2525 General Turning CT2525 Roughing CT3525 Heavy Interrupted Cutting CT3525 Stainless Steel Turning CT3015 How to Choose the Right Grade When selecting a carbide insert grade, consider the following factors: Workpiece Material Different ISO material groups require different carbide substrates and coatings. ISO P – Steel ISO M – Stainless Steel ISO K – Cast Iron ISO N – Non-ferrous Metals ISO S – Super Alloys ISO H – Hardened Steel Machining Operation Finishing → Higher hardness Semi-finishing → Balanced grade Roughing → Higher toughness Interrupted cutting → Maximum toughness Cutting Speed Higher cutting speeds generally require grades with superior wear resistance, while lower speeds and unstable conditions benefit from tougher grades that resist chipping. Why Choose Zhuzhou Century Tool Grades? Premium ultra-fine carbide substrates Advanced CVD and PVD coatings Consistent edge preparation Stable chip control Long tool life Suitable for high-efficiency CNC machining OEM grade matching available Frequently Asked Questions What is the best grade for general steel turning? CT2525 is our universal grade, offering an excellent balance of wear resistance and toughness for most steel turning operations. Which grade is suitable for heavy roughing? CT3525 provides superior toughness and impact resistance for heavy-duty machining and interrupted cuts. Which grade works best for stainless steel? CT3015 is specifically designed for stainless steel machining, reducing built-up edge while improving tool life. Can one grade machine multiple materials? Yes. CT2525 performs well across many carbon and alloy steel applications, making it an excellent general-purpose choice. Do your grades replace Sandvik, Kennametal, Iscar, Mitsubishi, Korloy, or ZCC inserts? Yes. Our grades are engineered to provide equivalent performance and can often replace major international brands in many turning applications.
