Copper added alloys
Copper added alloys
(OP)
In one of the process document it has been indicated that the copper and the copper added alloys shall not be used in Wet H2s environment.One vendor has quoted for 17-4PH material for the shaft sleeve which contains 4 % copper. Why cu shall not be used for H2S environment. Thanks to clarify





RE: Copper added alloys
Possibly Stress Corrosion Cracking.
desertfox
RE: Copper added alloys
Have a look at this article:-
http://www.npl.co.uk/upload/pdf/stress.pdf
desertfox
RE: Copper added alloys
RE: Copper added alloys
Your welcome
RE: Copper added alloys
RE: Copper added alloys
RE: Copper added alloys
It sounds to me like a translation issue, where "copper-based" got translated to "copper-added".
17-4PH in the DH1150 condition has been used for decades in H2S environments and is specifically listed in ISO 15156-3 in this conditon.
rp
RE: Copper added alloys
[Copper Alloys]
- The copper alloys, such as 90/10 Cu/Ni or 70/30 Cu/Ni, are acceptable in NACE MR0175. However the corrosion rate may be high in wet sour service if dissolved oxygen is present. Some oil producers have an experience of Galvanically Induced Hydrogen Stress Cracking in copper alloys.
- In sour service containing NH3 (amine, ammonia, salt deposit environment, etc.), brass and bronze shall not be used. The use of Monel (70Ni-30Cu), 90/10 Cu/Ni or 70/30 Cu/Ni should be also avoided because the service can lead to rapid corrosion and possible SCC.
[Copper Containing/Bearing Steels]
- NACE MR0175/0103 allow use several steels including 17-4 PHSS (< 33 HRC). However, in sour service containing NH3 (amine, ammonia, salt deposit environment, etc.), copper containing steels should be avoided except a trace copper (< 1%) containing steel to promote SSC resistance. 0.2-0.3% copper containing steel has greatly improved the HIC resistance.
- Many oil producers are using 17-4 PHSS only for valve stems, shaft, sleeve bearings, thrust bearings and mechanical seal throttle bushings in pumps and compressors which are required high strength in wet sour Service without NH3.
Thomas Eun
RE: Copper added alloys
RE: Copper added alloys