Hi, does any one know what the bog standard bolt material or spec is used in Korean , and Chinese shipyards for engine room and pump room piping.

All my quick books and cheat sheets seem to indicate ATSM A193 B7 bolts - But they are all geared to The "petroleum industry" . Currently working as tech super for FPSOs and we never know on the marine side whether we are "petroleum" or shipping". The FPSO's were originally built as tankers.
If it wasnt for COVID , I would go out myself and get some photos or rubbings from end of bolts , but that is not an option now.

All those years I was on ships , I never paid much attention to these little markings on the bolt heads . They were all just bolts to me then.

There is another standard called ATSM F568M which may be used. Ifound this on google

https://www.portlandbolt.com/technical/ ... astm-f593/

Looks like ATSMF568M is more of the cheapcharlie option which probably goes with shipbuilding.

Well I reckon all those markings on those foreign bolt heads translate ( according to my translations dictionary ) as non sparkers type jobbies.
The content metal material comes up as,
Wait for it,
SHITMETAL

Which allways used to be in the old days as diecast zinc content

Dont think so.- Korean and Chinese yards build over 75% of the worlds shipping by tonnage. So they must be doing something right.