Questions Concerning UG-84 Base Materials

[Noids]

Please help me understand the following:

For UG-84(g)(5), How are the impact test energy values established for the "base materials"? Does "base material" refer to the impact test specimen energy value requirement from Figure UG-84.1 that is to be met? Or is it the energy values of the certificate from the material manufacturer that must be met? For example, a vessel design consisting of 2.25” thk SA-516-70N plate would require the average energy for three of the specimens to be 15 ft-lbs with one specimen not less than 10 ft-lbs (2/3 of the average energy required for three specimens from General Note B).

1)From ASME UG-84(C)(4)(a): Except for materials produced and impact
tested in accordance with the requirements in the specifications
listed in General Note (c) of Figure UG-84.1, the applicable
minimum energy requirement for all specimen
sizes for Table UCS-23 materials having a specified minimum
tensile strength less than 95,000 psi (655 MPa) shall
be that shown in Figure UG-84.1 ….

2)From ASME UG-84(g)(5): Impact values shall be at least as high as those required
for the "base materials".

 

[SnTMan]

I think you will find base material means Not Weld, Not Heat Affeccted Zone.

Regards,

Mike

 

[Noids]

Could we say that an impact test specimen consists of the base material, the HAZ & the weld? Also, if a vessel is built to ASME Section VIII Div.1, the impact test requirements to be met are in Figure UG-84.1? For the example above in Figure UG-84.1, 2.25" thk plate (SA-516-70N) the energy values are 15 ft-lbs & 10 ft-lbs min. However in SA-20, the acceptance values are 15 ft-lbs & 12 ft-lbs min. My understanding is to meet ASME section VIII 10 ft-lbs min is required?

thank you

 

[SnTMan]

Noids, that's pretty much it. Typically UG-84 will govern unless a more strict requirement is imposed by, say customer spec. Also note that high alloy steels are governed by Part UHA.

Regards,

Mike

 

[Noids]

SnTMan,

thank you for your response.