Seat ring and stem sealing area surfaces are subjected to the overlay and to the mentioned issues. The Project specification requires it. See pictures below:
Our valve supplier raised an NCR to avoid to replace a welding overlay on carbon steel LF2 material made with one pass of AISI 309 and second pass of AISI 316 (3 mm of cladding).
The welding process shows a big porosity (out of acceptance criteria), there are in the cladded surfaces many point...
A supplier of Heat exchanger made in SA 387 Grade 9 steel to avoid the PWHT is going to use a filler metal ERNiCr-3 (alloy 625).
The welding process is made with 4 passes of GTAW (thickness qualified 9mm).
It is sufficient this process to avoid the PWHT that is usually mandatory required for...
Thanks for your answer but as far as I can see nobody can understand the reason of that choice like me. Anyone had similar experience with this issue will be well accepted.
It is not a good solution to connect AISI 316 pipe with Carbon Steel body valves. For sure the surface and the possibility of humudity can increase or not the problem. Remember that galvanic corrosion can occur only in presence of water beetweend them. If you don't have the conductive solution...
The justification is included in the specification from the Client that had experencied in the past such problems on Field. That's why they have substituded the items. I have no more information than this, that's why I need somebody that knows something about this and can give me more details.
Can anyone explain me why in high H2S content conditions the use of F22 Modified materials is preferred to the X60. I want to clarify that the F22 Modified has SMYS=60 Ksi (identical to X60).
The justification I fuond is:
"Initial problems discovered very early on were related to the X60 piping...
I have to verify the feasibility of application of a Epoxy - Urethane Coating (SP-2888) coating on a substrate of 3LPe (3-layer polyethilene. Being the first (SP-2888) a thermosetting resin and the substrate a thermoplastic resin, which kind of reccomendation shall I take into account to...
I have to purchase a line pipe with a material grade L450 ME. I suppose that "M" stay for thermomeccanically rolled condition. But the ulterior suffix "E" for what is?
I know that the NACE ISO 15156-2 gives the limit of 0.3 KPa of partial pressure of H2S in the gas phase and that NACE 0103 mention 50ppm in the water phase.
But in my case having crude oil and no other indications, I have no idea about how can I compare my analysis with the above.
On the other...
I'm working on a 16" carbon steel pipeline that transfer crud oil at 90°C.
This Crude Oil has the following characteristics:
Specific gravity at 35°C = 0.95
Sulphur content = 3,5%
Viscosity = 220 Cst
Water sediment = 1%
I read a lot of articles that indicate 1% as a limit for sulphur on crude...
The only requirement of NACE is that the hardness shall not be above 45 HRC and that the material shall be supplied solution annealed or annealed and cold worked. Post weld heat treatment is usually not carried out and not necessary, for high thickness and big components welding, the heat...
The answer is that the Carbon Steel has already failed, in 2 years is completely destroied (in some points the casing pipe is perforated by the corrosin) and they has to replace with a better material.
Considering the content of H2S I would prefer to go to Superaustenic alloys in place of Superduplex. I read that duplex/superduplex material are more prone to SSC in H2S enviroment above 20KPa of partial pressure. The superaustenitic materials like UNS S31254 (254-SMO) has the same PREN of...
In my experience both AISI 309 and AISI 310 series are more than enough considering that are specifically applied for high temperature service and very resistant to creep and corrosion at high temperature service. Moreover are the more used for flare application cause of the high temperature...
