Bellows - Type Expansion Joint Failure
Bellows - Type Expansion Joint Failure
(OP)
Has anyone had any experience with bellows-type expansion joint failure due to stress corrosion cracking caused by Chloride. Material of construction is 304 SS. Fluid is 125psig steam. Related questions:
1) Is 304SS a suitable material for steam service
2) Is Inconel 625 a suitable matl for steam service.
3) Is there a protocol for hydro testing such joints (prior to startup).
4) Does it make a difference (in terms of preventing corrosive attack) whether the joint is placed in horizontal or vertical position?
1) Is 304SS a suitable material for steam service
2) Is Inconel 625 a suitable matl for steam service.
3) Is there a protocol for hydro testing such joints (prior to startup).
4) Does it make a difference (in terms of preventing corrosive attack) whether the joint is placed in horizontal or vertical position?





RE: Bellows - Type Expansion Joint Failure
As far as testing goes, that would be covered by ASME B31.3 Appendix X.
Edward L. Klein
Pipe Stress Engineer
Houston, Texas
All opinions expressed here are my own and not my company's.
RE: Bellows - Type Expansion Joint Failure
RE: Bellows - Type Expansion Joint Failure
However, if your system is anything like those I've experienced, you may have a large number of austenitic components throughout your system (check control valve trim, boiler tubes, safety valve trim, any vessel internals, strainers, intrument components, etc.) If you have a large system with many austenitic components, upgrading your way out of the problem may not be a cost effective choice.
Do you know what is causing the chloride contamination of your steam system? Can you isolate the contaminate? In dealing with large steam systems, I've typically worked to isolate the contaminate, rather than attempt to upgrade all of the austenitic components. Upgrades were limited to components with very high consequences of failure. Once the contaminate is isolated, you may have a couple "residual" failures, but generally, the system (if blowndown properly) will clean itself up fairly quickly. We continue to operate today with a large number of austenitic components in our steam systems.
One final thought: Depending on the component, downgrading the metallurgy can also be effective. Ferritic stainless steel components (valve trim, traps, rotating equipment) faired very well when exposed to chloride contamination in our steam system.
RE: Bellows - Type Expansion Joint Failure