Impact test energy

[Paulettea]

Dear All,

Please help me understand some points regarding Impact testing required energy as per ASME BPVC.

First question is what is meant by minimum specified yield strength in Figure UG-84.1? Is it the value specified by the code in II-D or is it the value obtained from mechanical test results?
I mean I have seen test results showing the yield strength well above that specified by the code in II-D.

Second question is that why is there a difference between the values in Figure UG-84.1 and the data in SA-20 Table A2.15? Foe example for SA-516 60 the minimum average value for 3 specimens is mentioned to be 20J as per Figure UG-84.1 however in SA-20 Table A2.15 it is mentioned 18J. Furthermore, the minimum for 1 specimen is 16J as per SA-20 Table A2.15 but the value of minimum for 1 specimen as per Figure UG-84.1 is 2/3 of the required average energy for three specimens which makes it 13.33J.

Third question is that what happens if the impact test is required in temperatures colder than those specified in SA-20 Table A2.15? Is it required to change the minimum required energy?

Warm Regards

 

[david339933]

Min. Specified Yield Strength is that in Sec. II. 32,000psi for SA-516-60.
I don't think you are reading Fig UG-84.1 correctly. Min. required is 15ft.lbs for SA-516-60.
Required energy is the same regardless of temp.

 

[david339933]

Sorry, didn't read Joules....assumed ft.lbs.

 

[weldstan]

MSYS is defined by the material ASME/ASTM specification as included in ASME Section II Part D.

 

[SnTMan]

Second question is that why is there a difference between the values in Figure UG-84.1 and the data in SA-20 Table A2.15?

SA-20 is a general plate spec, it provides impact test requirements, including energies. These can be used if no other guidance is available. It also allows different values to be specified by the purchaser.

UG-84 is part of a Code of Construction. These values are mandatory for work falling under that Code. They also apply to product forms other than plate. Note also that SA-20 values apply only to certain heat-treats, normalized and Q&T. Why the difference between SA-20 and UG-84? I don't know. Different committees perhaps.

Third question is that what happens if the impact test is required in temperatures colder than those specified in SA-20 Table A2.15? Is it required to change the minimum required energy?

No, neither in SA-20 nor UG-84.

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

I use SA-20 to select appropriate plate material for a design temperature. UG-84 is for materials and welds.

Regards
r6155