Seacocks marked BN 40 or CN 40?

[nigelmercier]

My seacocks appear to be marked either BN 40 or CN 40, does this indicate the material they are made from?

 

[vyv_cox]

Don't know. PN is the pressure rating and DN is the bore. Your pics look like CN to me, but could they be one of the others? The material will be something like CW617N, or possibly MS58, dependent upon the standard in use (both leaded brasses), CZ132 is DZR.

 

[nigelmercier]

Thanks Vyv, so should I look for other markings?

 

[vyv_cox]

Thanks Vyv, so should I look for other markings?

Yes but it looks chromium plated to me, unless stainless, in which case almost certainly brass. I don't know of either bronze or DZR valves that are plated.