Low temperature nitriding and chrome plating process

Abstract

A steel part, such as a mechanical centrifuge screen of mild steel with a nitriding layer on all exposed surfaces of the steel to form an effectively hardened substrate layer, and electroplating the nitrided steel part. The surface treatment method provides an improved wear resistance and effectively provides improved erosion and corrosion protection of the steel part.

I claim:  
     
         1 . A surface treatment method for obtaining improved life of steel parts, comprising the following steps in the sequence setforth: 
 (a) Nitriding the steel part on all exposed surfaces; and    (b) Electroplating the nitrided steel part.    
     
     
         2 . The method of  claim 1 , wherein the nitriding is formed by vacuum ion-nitriding.  
     
     
         3 . The method of  claim 1 , wherein the nitriding is formed by salt bath nitriding.  
     
     
         4 . The method of  claim 1 , wherein the nitriding is formed by pulsed ion-nitriding.  
     
     
         5 . The method of  claim 1 , wherein the nitriding is formed by gas nitriding.  
     
     
         6 . The method of  claim 1 , wherein the electroplating is hard chrome plating.  
     
     
         7 . A surface treatment method for obtaining improved life of steel parts comprising: 
 (a) applying a nitrided layer about from 0.001 to 0.010 inches thick to the steel part on all exposed surfaces; and (b) applying a hard chrome plating layer from 0.001 to 0.050 inches thick to the nitrided steel part.    
     
     
         8 . A surface treatment composition comprising: (a) a first layer of nitriding; and (b) a second layer of hard chrome plating.