Gate Valve Trim Materials 2

[shaff]

Hi,

We need to procure gate valves for our project and I am doing Technical Assessment of Valve materials
Datasheet given by design engineer asks for AISI 410 STELLITE COATED material whereas vendor is offering F6+STELLITE.

Is this change acceptable? Valve will be working in moderate temperature and pressure and handling Hydrocarbon fluid (non sour).

Seeking your guidance on this....

Shaff

 

[uaepiping]

Check API trim table for materials. AISI and F6 are same.

 

[hsbcn]

Here's a handy API trim chart:

[URL unfurl="true"]http://alloy-valves.com/Alloy-Valves-Product-Range/API-600-trim-chart.php[/url]


Corrosion resistant, exotic alloy valves from The Alloy Valve Stockist in Barcelona, Spain [URL unfurl="true"]http://www.gate-valves.com[/url]

 

[gerhardl]

In my opinion you should take a broader view than just look at the offered material compabillity to actual process data. The questions you should start with, as a suggestion, are for instance:

Reason for specification: Experience, requirement from end-user, earlier use of standard, standard set without experience of waht is used and commercial available, standard set without regard to price, standard set based on supply from one (earlier) supplier etc. etc ?

Consequences: Who will take responsibillity and pay for any negative consequences if proven wrong during guarantee periode?

First after this is answered your section about use and experience (and references from vendor) should be raised. Is the reason for the vendors offering that he can't supply to full spec, or only wishes to be competitive in price? This is very often the reason you will get alternative material offerings!

 

[shaff]

Thanks gerhardl..!

A bit of reading the Avenor's book and internet search has brought me to this conclusion,

AISI 410 is a matensitic steel which is covered in many specifications, F6 is a grade of ASTM material spec A182 which is basically AISI 410 steel with specific heat treatment procedure. This however, needs more citation anyways...
For the completion of Technical Bid Evaluation, I am going to raise a Technical Query to the vendor asking the reason for this deviation and as you've said, commercial reasons are mostly involved with these type of deviations.Vendor also offering SS ball in place of A105+ENP coated balls, which is a costly affair...

Thanks
Shaff