Effect of Extrusion Die Profile on the Uniformity of Nitrided Layers

Abstract

The nitrogen concentration field generated during gas nitriding of a steel plate having profiles of varying complexity is considered, and case-depth and concentration fields are predicted in the nitride layer using finite element model. The microhardness and case depth in the resulting nitrided layer are measured. It is found that predictions of case depth and measurements are in qualitative and quantitative agreement. Experimental and numerical studies show that the nitrided layers are not uniformly formed, and hence a proper hardness may not be achieved in some regions of the bearing area of an extrusion die. It is found that the curved and flat surfaces have more uniform distribution as compared to corners. The distribution at corners significantly depends on the value of angle.

Keywords:

• Case depth
• Die design
• Diffusion analysis
• Extrusion
• Finite element analysis
• Gas nitriding, Microhardness
• Nitride layer
• Steel
• Surface hardening

ACKNOWLEDGMENTS

The author acknowledges the support of King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia and KACST through project ARP-23-19 for this work.