Resistance of high-alloy steels to carburizing

Conclusions

• 1. Standard chromium-nickel austenitic steels Kh23N18 and Kh18N10T have a low resistance to carburizing. Steels Kh20N14S2 and Kh25N16G7AR have a better resistance to carburizing. Ferritic steel Kh25·Yu5 is characterized by absolute resistance to carburizing.

• 2. An increase of the silicon content from 2.16 to 2.8% in steel Kh20N14S2 and from 0.34 to 1.15% in steel Kh25N16G7AR raises their resistance to carburizing. The optimal silicon concentration to ensure resistance to carburizing is 2.55–2.8% for steel Kh20N14S2 and 1.15% for steel Kh25N16G7AR.

• 3. The reduction of the manganese content of steel Kh25N16G7AR with a medium silicon content increases its susceptibility to carburizing, which approaches that of steel Kh23N18. A 5% Mn addition to steel Kh20N14S2 makes it possible to reduce the silicon concentration while retaining the high resistance to carburizing. With an increase of the silicon content from 1.27 to 1.97% the chromium-nickel-manganese steel Kh20N14G5S becomes more resistant to carburizing.

• 4. The addition of boron to steel Kh20N14G5S and the reduction of the nickel content from 13 to 9% lower its resistance to carburizing.

The addition of 0.2% N increases the resistance to carburizing of steel Kh20N14G6SR, and an increase of the nitrogen content to 0.4% makes steel Kh25N16G7SAR resistant to carburizing.