×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

# 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??

### RE: Impact Test Exemption for Pressure Vessel as per ASME UCS 66

Mech2325, first understand that typically the MDMT of a vessel is not generally determined in reference to a single component, all components must be considered.

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

(OP)
Sntman

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

I would set it no lower than the required MDMT, -60 C.

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

(OP)
sntMan

Thanks again for your valuable feedback

### RE: Impact Test Exemption for Pressure Vessel as per ASME UCS 66

hi

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

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!