Ball and Stem Materias - Ball Valves

[VIVIANARICO]

Good day, my client piping class requires us in a ball valve, the ball and the stem are in material SS grade 316.

One of our 20” rating 300 valve was replaced under warranty by the supplier, and the new valve has supplied materials, ball is in A105 + ENP (Electroless Nickel Plating) and stem is in AISI 4140 + ENP (Electroless Nickel Plating). Since the production time is very long, we want to move consultation with our client to accept the available valve, but to have a better argument, I want to know the differences, advantages and disadvantages if these materials (ball and stem) change.

The valve will be used in a natural gas compression station at the entrance of the station, and its position is normally open.

If anyone can help me, I appreciate it, and exuse my english.

Regards,

Viviana Rico Medina

 

[SJones]

As a corrosion resistant coating, ENP has established anti-corrosion performance. The principal issue with it is reliability: it can be prone to breakdown. Where this happens, a bimetallic corrosion mode is established with the substrate leading to accelerated corrosion.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[VIVIANARICO]

Hi Steve, thanks a lot for your answer, did you have any experience where de ENP coating was breakdown?

Our aplication is natural gas and the valve is normally open, it could be improve the life cicle of the material? i refer the fact that the valve is "fail closed", and this fail is only in a shutdown event.

Thaks again.

Best regarts

VRM