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Maximum impact test energy

Maximum impact test energy

(OP)
Hi, I have a certificate of a plate, A 240 TP 316/316L thk.15mm, Rm=570 MPa, Rp0,2%=298Mpa, HB=169 Brinell, with Absorbed energy of Impact test 450 J.
Ok, it's stainless steel, but I think this value it's too high... What dou you think? Is it possible?

RE: Maximum impact test energy

At what temp? AT low temp yes I would believe it.

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P.E. Metallurgy, Plymouth Tube

RE: Maximum impact test energy

The austenitic stainless steel materials can have CVN values this high.

RE: Maximum impact test energy

Hi ElCidCampeador,

in the scope of ASME BPVC and piping codes for evaluation of impact test values there is no requirements for absorbed energy. There are only requirements for the minimum lateral expansion opposite the notch, e.g. :
  • ASME VIII/1, UHA-51(a)(2)(-a) shall be no less than 0.38 mm (0.015 in.), when the MDMT is −320°F (−196°C) and warmer,
  • ASME VIII/2, 3.11.4.1.(b) shall be no less than 0.38 mm (0.015 in.), when the MDMT is −320°F (−196°C) and warmer
  • ASME B31.3, Table 323.3.5 shall be no less than 0.38 mm (0.015 in.)
In the scope of ASME BPVC, if on the above mentioned certificate the lateral expansion is not stated this certificate have to be rejected.
But acc. to my experience after rejection you will get immediately a apology by the material manufacturer for the spelling mistake and a new certificate with beautiful lateral expansion values.

Regards - Juergen

RE: Maximum impact test energy

(OP)
450 J @ -50°C

Is there a way to check if this is a true value, knowing the standard tensile properties?

RE: Maximum impact test energy

A tensile test is for the strength and stiffness of the material, Charpy impact test is a cheap way of measuring/correlating to material toughness.

Which location is this test for, how many samples at this location were tested and what energies were achieved? It's common to have a significant scatter in impact energies for a similar test location.

RE: Maximum impact test energy

Quote:

Is there a way to check if this is a true value, knowing the standard tensile properties?

No. Additional CVN testing would be required of the heat of material.

RE: Maximum impact test energy

See SA-240
S1.6 Records—The recorded results shall include the
specimen orientation, specimen size, test temperature, absorbed
energy values (if required), and lateral expansion
opposite the notch.

Regards
r6155

RE: Maximum impact test energy

450lb-ft sounds like it may be the max of their machine, I have seen people forget the ">" sign when you max out an impact test.
I have seen this happen on 600lb-ft machines testing duplex stainless, the pendulum just stops, and you ruin the striker.

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P.E. Metallurgy, Plymouth Tube

RE: Maximum impact test energy

At -50ºC SA 240 316/316 L impact tests are exempted. See UHA-51.
Try to avoid problems and waste time when tests are not required.

Regards
r6155

RE: Maximum impact test energy

(OP)
Thank you all.
Singular value of absorbed energy are 449, 450, 449. Lateral espansion, average value, is 2,29 mm

The test was taken after solution heat treatment (it's a test coupon of a formed head): may the heat treatment increase the absorbed energy?


@r6155
Wasting time? I know UHA-51, but impact test IS required by client despite of exemption by code.

RE: Maximum impact test energy

What is the minimum value of impact absorbed energy required by Client?

Regards
r6155

RE: Maximum impact test energy

(OP)
27J

RE: Maximum impact test energy

Austenitic materials are generally recognized for their lack of ductile-to-brittle transition behavior. In other words, they do not generally display a reduction in impact energy as the test temperature is reduced. By contrast, ferritic and martensitic materials-such as the carbon steels, alloy steels, and 400-series stainless steels-exhibit reduced toughness as test temperature is reduced.

Hence, ¿wasting time?: YES

Regards
r6155

RE: Maximum impact test energy

While your Client is wasting his money, you have satisfied his requirement. And as others have stated, those absorbed energy values can be achieved.

RE: Maximum impact test energy

My point of view is ethic. I try to convince my client to save money and time. I gained several clients in this way.

Regards
r6155

RE: Maximum impact test energy

You now have more ammunition to convince your client that he is wasting his money, but as this old saying goes, "You can lead a horse to water but you can't make him drink."

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