Valve

[samsarani]

Hi all
I am involve of a project ( gas compressor station). according to spec. of project contractor should supply all valve with A350 LF2 ( though it is over spec because we don't have cold services only site condition is -12 c in winter and fluid temperature is 40 c).
as request of client we test material of one of them. result shows that material is forge and comply with LF2 requirement(chemical composition and physical properties) also body pass LF2 class 2 Charpy test but flanges didn't pass Charpy test in -46 for LF2 class 1 and -18 for LF2 class 2. the size of all valves are under 10 inches and rating is 600 #. if we take into account material of valves are A105, will We use them on our project. is there any risk of using those valves specially in winter ( worse case which weather temp. is -12 and station is stopped) or need any modification and restriction for using these valves).

thanks ALL

 

[jmec87]

Yes, there is significant risk of failure. Some A105 flanges (and some supposedly A350 LF2 flanges that upon further testing did not meet the LF2 charpy requirements) have failed at temperatures warmer than -29°C. See below (or search the internet) for examples and discussion.

https://www.thefabricator.com/tubep...nd-cures-for-ductile-spool-component-failures

https://emploi.belgique.be/sites/de...es/prev_zwareong/ongevalsnota/enm03ong008.pdf

https://www.absa.ca/media/2191/ib20...langes-for-low-temp-service-in-sec-viii-1.pdf

 

[samsarani]

Thanks Jmec
but as you know most of valves and flanges in gas treatment plant are A 105. in our case by Micrography on material shows they have fine grain that can cause it heat treated well (on other evidence is the body passed the Charpy test but flanges cant). sample valve was 4 inches which body and flanges get forged and heat treated together.

 

[mk3223]

sample valve was 4 inches which body and flanges get forged and heat treated together.

Basically, the valve can't be good if the "part" of it can't meet the "Client Requirements".