Effect of carbon on the structure of the nitrided case on steels of the Kh13 type

Conclusions

• 1. The structure of the nitrided case on stainless steels with 13% Cr, the formation process, and the hardness of the case depend on the carbon content of the steel and also the nitriding conditions.

• 2. At 620\dg and 540\dg the \ga\ar\gg transformation can occur during nitriding due to the fact that nitrogen sharply lowers the transformation temperature of austenite. Because of the difference in the concentration of nitrogen through the cross section of the case, the transformations occurring within the case itself can also differ during nitriding.

• 3. The nitrided case has a high hardness on all steels investigated after nitriding at 540\dg. The reason for the high hardness through the \ldferrite\rd zone on steels 1Kh13, 3Kh13, and 4Kh13 within the limits of a single layer is the microstresses in the \ga-lattice and the precipitation of phases.

• 4. The higher the carbon content of the steel, the more the hardening is due to precipitation of a hard phase of the Cr₂N type.

• 2. The hardness of the case obtained at 620\dg is affected by the dispersity of the CrN phase. The higher the carbon content of the steel, the greater the coalescence of the nitrides and the lower the hardness of the case.