The dual layer casting  process requires very tight control of casting conditions ( melt temperatures, cooling rates, and pour timing ) to produce a clean, sound metallurgical bond between the two alloy layers. 

Two alloys requires two melt units with the added operational cost.

Chrome  electroplating has undesirable environmental costs and risks and is under  tight EPA regulation. The Department of Defense policy calls for the replacement / reduction of hard chrome electroplating in military components, whenever suitable alternative technology is available.