Impact Test Exemption for Pressure Vessel as per ASME UCS 66
Impact Test Exemption for Pressure Vessel as per ASME UCS 66
(OP)
Hi all,
As per UCS 66 (b)(3) "When the minimum design metal temperature is colder than −55°F (−48°C) and no colder than −155(−105°C), and the coincident ratio defined in Figure UCS-66.1 is less than or equal to 0.35, impact testing is
not required".
My question in this matter is that, if for example, you want to go below -48°C and the ratio is below 0.35, then what will be the rated MDMT of your vessel in this case. For example the required MDMT is -60°C and the MDMT you are getting is -48°C. Now, if the ratio comes out to be 0.3, for example, what will be the MDMT now. Will it be -105°C??
As per UCS 66 (b)(3) "When the minimum design metal temperature is colder than −55°F (−48°C) and no colder than −155(−105°C), and the coincident ratio defined in Figure UCS-66.1 is less than or equal to 0.35, impact testing is
not required".
My question in this matter is that, if for example, you want to go below -48°C and the ratio is below 0.35, then what will be the rated MDMT of your vessel in this case. For example the required MDMT is -60°C and the MDMT you are getting is -48°C. Now, if the ratio comes out to be 0.3, for example, what will be the MDMT now. Will it be -105°C??





RE: Impact Test Exemption for Pressure Vessel as per ASME UCS 66
But, for your example, yes the vessel MDMT may be set as low as -105 C, but it need not be set below the specified MDMT, -60 C in your example.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Impact Test Exemption for Pressure Vessel as per ASME UCS 66
Thank you for your valuable feedback. Yes, i know, the vessel MDMT comes by taking the warmer of all the components' individual MDMT's. But, in case of carbon steel, the least you can get is -48oC. Now, if the design MDMT is -60o and the ratio from UCS 66 comes out to be 0.34. What will be your final adjusted MDMT??
RE: Impact Test Exemption for Pressure Vessel as per ASME UCS 66
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Impact Test Exemption for Pressure Vessel as per ASME UCS 66
Thanks again for your valuable feedback
RE: Impact Test Exemption for Pressure Vessel as per ASME UCS 66
even if impact testing may be not required for base metal before assembly as per UCS-66, impact testing may be required for the welding procedure as per UCS-67
regards