qpq on Monel K500? 3

[salmon2]

We want to improve wear resistance on a K500 part. But not sure if qpq is a good choice. Any suggestion is welcome. The part is a ball valve and will open/close many many times so want to add some surface treatment.

One engineer in our group points out that qpq process needs certain Cr amount to adhere... But K500 does specify any Cr, any comments on this also. Thanks a lot in advance.

 

[metengr]

salmon2;
There is really not enough information to provide technical guidance, other than, given your suggestion and the substrate being Monel, I would suggest looking at a barrier coating technology (thin film) or surface modification - plasma or ion sputtering to try to increase wear resistance.

Are you sure you need increased hardness for wear? What is the application that requires increased wear resistance?

 

[salmon2]

Thank you metengr,

Firstly, correction to my first post, "K500 does Not specify any Cr".

It is a ball valve in the downhole application. It will open and close under high differential pressure up to 20Ksi. Also there is elastomer seal feature between ball and seat. So scratching on the ball will affect sealing also as it will pass sealing material every time when open and close. We want to increase wear resistance and reduce friction but with wear being the primary concern. The seat will be possibly made of Inconel 718.

 

[jbeckhou]

I will suggest Armoloy coating. We use the process for our FC type Hyd. Stems, (Gate Valves).

Petrotrim Services

http://www.petrotrim.com

 

[TVP]

salmon2,

QPQ treatments are not suitable for nickel-based alloys like Monel because Ni does not form a stable nitride layer the way that ferrous metals do.

 

[salmon2]

Thanks a lot guys, especially TVP because that is what I want to know most - general knowledge.