TRIM 16 in API 600 1

[Flo65]

Hello,

Some suppliers are talking about trim Nr 16 in API 600 but in my own versopn there is no mention of this trim. only for trim 12.

Does somebody can tell me which version is talking about trim nr 16 ?

thank you.

 

[rneill]

A bunch of new Trim codes (now up to Trim code 18) were added to the 2005 Edition of API 602 and to the 2009 Edition of API 600.

Trim code 16 is basically an austenitic SS stem and full HF on the seating surfaces.

 

[Flo65]

Thanks.

What about valves in WCB body trim 16 ?
Some of suppliers told me that in this case seat and disc can be offered in CS (A105 for ex.) because API 600 mention "an overlay deposit such as stellite or equivalent can be used for seating surface where base material is equal or better than shell (body material)".

I thought that trim 16, even for CS valves such as WCB, should be F316 or CF8M + HF seat and disc.

Thank you in advance for your help as I have not the last edition of API 600 or API 602.

Regards.

 

[rneill]

Trim is defined as the stem, the obturator seat surfaces (e.g., the wedge/disc seat surfaces), and the body or seat ring seat surfaces. The wedge/disc itself is not "trim" and the trim codes have no bearing on what materials are to be used for the wedge itself.

As far as the obturator (i.e., the wedge/disc), it shall be steel or base material compatible with the pressure temperature rating and at least equal in corrosion resistance to the body material.

If you want the wedge/disc to be something other than equal to the body material (though this would be unusual) then you need to separately specify that.

The trim code only applies to the seating surface itself.