High-speed steel containing approximately 5% cobalt, commonly corresponding to:
• M35
• JIS SKH55
Common heat-treated hardness is approximately HRC 64~HRC 65, actual values vary depending on tool manufacturing requirements.
The addition of cobalt improves the high-temperature hardness and wear resistance of high-speed steel, making it more suitable for thread machining environments requiring high heat resistance and wear resistance.
The tungsten-cobalt ratio of SKH55 (M35) is a key advantage for tap manufacturing. SKH55 (M35) contains 5% cobalt, and its key advantage lies in the significant improvement in hot hardness (red hardness) and wear resistance, making it an ideal material for manufacturing high-efficiency cutting tools such as taps.
Material Properties and Advantages
• High Hot Hardness: Maintains high hardness even at temperatures between 600°C and 650°C, preventing softening during high-speed tapping.
• Wear Life: The added cobalt formulation extends the cutting edge's lifespan and reduces wear during continuous operation.
• Deformation Resistance: With a hardness range of 63–67 HRC, it is less prone to chipping or deformation when working with harder materials such as stainless steel.
UGMIC Yujun Precision primarily uses this material for its HSS_Co cobalt-containing high-speed steel spiral taps and cobalt-containing high-speed steel extrusion taps specifically designed for stainless steel.
