Dowel Pin's Material 2

[zulsaid]

We are Oil&gas valve manufacturer. My question is it necessary to use stainless steel dowel pin if the body is stainless steel? Is there any problem if I'm using 52100 material? Because I'm thinking that the dowel pin does not expose to the environment.
I'm choosing 52100 material because I need the strength of that material. My freinds suggested to use 17-4PH but it's costly because in the markets very difficult to get dowel pin with 17-4PH material.

 

[CoryPad]

Are you sure the pin is not exposed? If it isn't sealed, then there can be some exposure.

Is the stainless body passivated? If so, and if there is some electrolyte, then there will be galvanic corrosion.

You will need to decide how likely it is that any galvanic corrosion will occur, how severe it will be, and the costs associated with that. Then, compare that to the cost of a high-strength stainless pin.

There are high-strength austenitic stainless steel pins available. Try Spirol.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[ash9144]

The dowel will be exposed to the environment. No matter the type of valve there will be some exposure through fugitive emissions, maitenance, other leaks. I've seen this problem often in acid services where external parts are lower grade than valve itself and the external parts corrode badly. Spend the money and go with higher grade material to start it will save headaches and money down the road.

 

[zulsaid]

Thanks Cory and Ash..

 

[zulsaid]

How is the performance of the SS304 and SS316? I am very difficult to find hex socket cap screw(allen Key) in the markets with ss316 material. In the market more familiar with 304, some people commented that not much difference between both material in terms of corrosion.

 

[CoryPad]

There is a lot of information available regarding the corrosion performance of 304 and 316 stainless steel. Perform a search at this site and using Google.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.