13% Cr. weld deposit on body (WCB grade). 1

[skengg]

hello to all,
i am actually bit confused on one clause of BSEN 1873 standard. i have attached picture of it which talks about seating surface requirements in BSEN 1873.
i actually want to confirm that can we weld deposit of 13% cr. or Hardfacing on WCB graded body, which will act as integral seat ring?
but as shown in pic, heading(b) states "austenitic or hard faced material can directly deposit on valve body but direct deposition of 13% chromium on to the body is not permissible."

So my main question, does this clause indicate we can deposit hard-faced(for e.g. stellite6) on WCB grade body but we can not deposit 13% chromium on to the WCB graded body?
thanks & regards.

 

[skengg]

sorry i guess i forgot to attach pic,
here's it is:

 

[SPDL310]

I'm not too familiar with this standard, but from what I interpret, no you can't weld 13% chrome directly to the body. Take this with a grain of salt as there may be some other sections in the code which disallow this practice, but it may be permissible to qualify a weld procedure using a butter pass of another material usually alloy 625 of sufficient thickness which you are able to weld 13% chrome on top of. The standard does seem to have a preference for a separate seat insert though so that may be the preferable option here.

 

[skengg]

SPDL310,
yea it seems so, actually we are making high pressure globe valve so separate seat ring doesn't seem good option for few reasons. standards do say that we can't weld 13%cr on body but can we weld hard-faced like stellite 6 on WCB body?

 

[SPDL310]

I understand the issues incorporating a seat ring in a high pressure valve, but there are some advantages as well. The primary of which is that the valve doesn't need to be removed from line, and sent to a machine shop for seat repair. As I said I'm not familiar with the particular code you are working with but the section you quoted does seem to allow hard facing as long as the welded material is above 1.6mm in finished thickness.

 

[skengg]

Yea i understand
thanks for discussing tho