coating for springs

[azzt]

Hi

I need to specify a coating for a helical spring to help prevent corrosion to temperatures up to about 300C.

Any help based on experience would be greatly appreciated.

Thanks

allan

 

[TVP]

What is the spring material and strength/hardness? What is the environment in which the spring will operated (automotive interior, industrial exterior, on the bottom of a boat anchor, etc.)? Does the coating need to be resistant to impact (stone impingement, etc.)? We should be able to assist you with some additional information on these topics.

 

[israelkk]

If the temperature is 300C then the spring material has to be compatible. Springs that intended to work at such temperatures are usually made of corrosion resistant metals such as Inconel 600, Inconel X-750. If it is for short duration other spring materials can used such as 17-7PH CH900.

http://www.webspawner.com/users/israelkk/

 

[azzt]

Hi

Thanks for your responses.

The spring is part of a pressure relief valve in a compressor, therefore it will be exposed to elevated temperatures for very short periods of time and rarely. Perhaps 300C is a bit extreme, that's the compressor exit temperature based on adiabatic compression.

Doing the sums based on BSEN13906-1 suggests steel type SM from BSEN10270-1, UTS 1430 N/mm^2.

Thanks again

allan

 

[NickE]

So then what is the long term max temp the spring will see if the pressure relief valve never opens?

I'd reccommend using something that can survive the peak temp you identified previously. I do know that the literature says 17-7PHCH900 can be used up to 315C...

17-7 is also a good alloy for springs in general. (IMHO)

 

[JAlton]

Several years ago, one major manufacturer switched to Stainless Steel Springs rather than Carbon Steel due to elevated temperatures in Air Compressors.
Typically Carbon Steel Springs are rated to 450F (232C) when installed in a Closed Bonnet design SRV.
SS Springs can go up to 800F (426C).

J. Alton Cox

http://www.delucatest.com