Try carburizing and quenching the whole part in a sealed quench or similar batch type furnace, making sure quench temperature is around 780 degrees C to reduce distortion.  If you desire to selectivley harden some areas then mask off those area which are not required to be hardened with copper masking compound or similar proprietary mixture to stop diffusion of the carburizing gas.

Alternativly harden and temper the part then gas or salt bath nitride the selected areas requiring wear resistance.  EN353 is suitable for nitriding and will produce an adherent wear resistant case.  Remember to temper after hardening at a temperature in excess of your nitriding temperature provided your core hardness specification will allow such treatment.  The nitriding operation if conducted at a temperature below the tempering temperature will stop part distortion and the only grinding allowance will be that necessary to compensate for the build up in the nitrided coating.  

Instead of using salt bath or gas nitriding use plasma nitriding (ion nitriding). It will give you a far superior surface with negligible and predictable growth.

Contact me if you need details.
Pramod Kotwal
info@nitron.nu