How to Determine MDMT for Matls. Predating MDMT 1

[bonkers]

I wish to determine the MDMT for ASTM A212 BFBX material which is not in Sect. II Part D. This vessel was built in 1962 and the mateial was with drawen in 1967. All of this was before the advent of MDMT in the 80's. Is it permissible to use the UCS-66 curve A (carbon steel) to determine the MDMT for this carbon steel?

Thank you for any input.

Bonkers

 

[SnTMan]

bonkers, it may be permissable to use Curve A, however I think you need to examine the NBIC and perhaps consult with your AI before going too far with this.

Regards,

Mike

 

[stanweld]

Vessels with SA-212 B were subject to the 4:1 safety factor back in 1962 and as such would be good to -20F. Are you rerating this vessel? SA-212 was replaced by SA-515 and SA-516. It could have been made to a fine grain melting practice (SA-516) or not (SA-515).

 

[metengr]

I would concur with the above advice on limiting use to no lower than -20 deg F, and using the catch-all curve A in ASME Section VIII, Div 1, Figure UCS-66 despite the fact that this material could have been supplied as fine grained, in accordance with A-300.

 

[Duwe6]

And you can always "Ask the Part". Lift out some material, enough for at least 5 Charpies [subsize is OK]. Start off by breaking 1 at -20°F. If it breaks ok, try again at -30°F. If the -30° one breaks OK, break 2 more -- your mandatory set of 3ea. results.

If the -20°F breaks low [brittle] try one at -10°, and on up the temperature scale. When you find the 'sweet spot' temperature, make sure that you get 3ea. breaks to certify your old material.