Impact-abrasive wear of nitrided tool steels

Conclusions

• 1. The wear resistance of the nitrided case under impact loading conditions is higher than under static loading conditions and depends on the strength and toughness of the case, which is determined by the composition of the steel and the structure of the case.

• 2. With increasing depth of the case the wear resistance first increases and then decreases. The case depth at which the wear resistance is highest differs for steels with different types of structures.

• 3. With a high hardness (HV 1340) the wear resistance is higher with a deep case −0.015–0.02 mm for high-speed steels R18 and R12, 0.065–0.075 mm for high-chromium steel Kh12M, and 0.12–0.13 mm for chromium — tungsten steels 3Kh2V8F and 4Kh5V2FS.

• 4. The recommended nitriding conditions are 520°C for 1 h (or 560°C for 20 min) for high-speed steels, 520–540°C for 6 h for high-chromium steels, and 520–540°C for 6 h (or 540–560°C for 4 h) for chromium — tungsten steels.