Coating 316SS inorder to not apply paste when mating with other steels

[noboost4you]

Hi, I just found this forum and it's been a great deal of help.

Here's the current scenario:

We manufacture and assemble needle valves. The needle valve stem is installed into a needle valve bonnet which is then installed onto the needle valve body.

The stem is made of 316SS, the bonnet of C12L14 steel, and the body of C12L14 steel. We currently apply Dow Corning's G-n Metal Assembly Paste to the threads of the stem (which when installed, coats the inside of the bonnet) and the external threads of the bonnet (which when installed into the body, coats the internal threads of the body).

This process of applying paste is all done manually which takes a good deal of time. We use the paste because of it's properties of protection against fretting wear and corrosion, low friction, reduces wear and helping to prevent seizing, galling, and excessive friction.

We're trying to speed of the process of applying the paste, but I also want to look at other alternatives and perhaps do away with the paste altogether.

Is there any kind of coatings available that can be applied to the stems and bonnets that would eliminate the need of the assembly paste?

One of our main reasons for using the paste is because of the molybdenum that makes its way into tiny imperfections inside the valve assembly and to reduce galling.

Thanks

 

[noboost4you]

Is my question to vague? Surprised no one has had any sort of input yet.

 

[Compositepro]

It seems to me that what you want to do will be much more costly but if you want to persue it contact Magnaplate.

 

[noboost4you]

After doing a little research I came across Magnaplate HMF. From their description the coating gives the part permanent lubricity and effectively ensures against galling and seizing.

Cost has not been evaluated yet as I'm trying to find any alternatives to our current practice. Of course changing from our current practice will significantly cost more, but may have a far greater payback.

Could a Teflon coating even be a suggestion?

 

[mighoser]

I'm assuming your galling is between the stainless and C12L14 steel. How about switching from 316SS to Nitronic 50 (XM-19). Light oil or between the steel parts should be sufficient.

 

[noboost4you]

Yes, the problem lies between those two materials.

While changing materials is an option, it's the last resort. I'm trying to see what coatings are available that can eliminate the use of assembly paste while protecting against fretting, wear, and galling. The coating also needs to have a low coefficient of friction and provide some lubricity.

I have found a handful of places who claim their coatings do what I need them to do, so we'll see.