Ion-nitriding

 
Description: Ion-nitriding is a thermal process by which nitrogen ions are diffused onto the surface of a metal. The process is done in a vessel called an ion-nitrider. The piece to be nitrided is placed inside the vessel. Air in the vessel is pumped out, and replaced with a nitrogen rich atmosphere. A negative charge is applied to the work piece, which causes nitrogen ions to bombard the work piece.
 
Ariel ion-nitrides cylinders, piston rods in the packing wear area, and variable volume clearance pocket stems.
 
Hardness values: Ion-nitriding increases the surface hardness of metals to improve wear resistance. The following table outlines the effect of ion-nitriding on the surface hardness of Ariel’s piston rods and cylinder bodies.
 

Material

Component

Base Hardness, Rockwell C

Ion-Nitrided Hardness, Rockwell C

Thickness of Hardened Layer, in

ETD-150

piston rods

29

57-63

0.005-0.006

Gray Iron ASTM A278

cylinder bodies

<20

57

0.006

Ductile Iron 60-40-18

cylinder bodies

<20

57

0.006

416 SST

VVCP stems

<20

70+

0.005

 
Ductile Iron cylinders of 80-55-06 are not ion-nitrided.
 
17-4PH Piston Rods are chromium nitrided in the packing travel area to a hardness level of 2500 Vickers.
 
Tungsten carbide coating can be applied as an option on piston rods for packing travel.
 
 
 

Ariel Corporation Application Manual  
26-March-2002