Debasis Of late, we, as forum members, find that you are raising (frequently) questions of academic and theoretical nature. It is difficult to give answers to general questions such as this. You should appreciate this. Forum members can at best inform you to refer to standard text books or reference materials (which i guess is not the intent of such discussion forum). Carburization and Nitriding - Heat Treatment of steel and steel components is quite vast. Each surface hardness approach has varied applications -as it appears that you are aware from the questions asked. I would suggest that if you have specific problems on each of the application from your needs or problems faced in doing the same and your plant's experience would serve as valuable input and guidance to discussion forum members participating in this, Probably forum members would be able to share their experience and expertise in helping or try to give inputs to solve similar problems if any from their experience in solving the same. I guess a discussion forum is meant to share problems by industries and if any unsolved specific problem is highlighted, this would help participating members to give insight on specific problem (which other users' might have experienced and would be able to share the same from either solving or from giving their input on the same). Hope this helps you to raise specific problems faced in future C.V.Srinivasan Nishi Engineers Pvt Ltd India Nov 20, 2007 E-mail: nishi@vsnl.com >It has been known that Nitriding can offer more surface >hardness compared to carburising and also as nitriding >introduces a significant amount of Compressive stress by >increase in volume it has very much beneficial w.r.t. >component's fatigue performance life. > >Q1. Can carburising case by virtue of it's volume change can >improve fatigue life ? > >Q2. Effective case depth in case of carburising is generally >measured by hardness profiling upto the thro' thickness >point where hardness reaches HRC50. Is there any such rule >for Nitriding effective case depth determination ? > >Q3. W.r.t. galling and wear resistance performance which one >is more effecyive between carburising and Nitriding ? > >Q4. Can bearings is better to be carburised or Nitrided ?