Nitrooxidation of cutting tools

Conclusions

• 1. Nitrooxiding is a new method of chemicothermal treatment in the atmosphere of an aqueous solution of ammonia or ammonia gas and water.

• 2. The diffusion coating on quenched and tempered high-speed steel after nitrooxiding consists of an outer zone of oxides and an inner zone rich in nitrogen.

• 3. The nitrooxided case imparts a dark color to high-speed steels and increases the hardness, wear resistance, and corrosion resistance. The increase in the dimensions caused by nitrooxiding can be reduced substantially in practice.

• 4. Nitrooxiding increases the life of cutting tools by an average of 100%, particularly forming and burnishing tools. Sharpening of nitrooxided tools only slightly impairs the operating characteristics.

• 5. Nitrooxiding increases the life of tools considerably more than treatment in water vapor. As compared with nitriding, nitrooxiding can be used more widely and is suitable for both fine and fine-cutting tools, where nitriding causes brittleness.