Technology

New Nitriding for Cold Work Tool Steel

"Laser hybrid forging" was used as a pretreatment for the nitriding to refine the microstructure of D2. The diffusion zone of the nitrided case on the D2 plate contained thick brittle boundary lines consisting of segregated nitride particles. On the other hand, the microstructure of the diffusion zone was very uniform and the thick brittle boundary lines disappeared as a result of the laser hybrid forging before the nitriding process.

Figure OM images of the cross section of the nitrided D2 samples. (a) and (c): as-received D2, and (b) and (d): pretreated D2