Mill MTR charpy standard

[TerryR1]

My governing standards for many of my projects require Charpy testing per ASTM A370. (Per ABS rules, DNV rules, ASME, etc).

However, nearly all the MTRs for available stocked material, that include Charpy results, do not list which standard the Charpy testing was done under.

So far this has not come up as a problem with the surveyors, so I'm having a hard time convincing myself that this material needs to be retested to confirm compliance with A370.

Have any of you come across this particular requirement-vs-availability issue? Would love to hear how you are handling it.

Thanks!

 

[redpicker]

I would consider you to be slightly off (putting it mildly) if you wanted to re-test material only because the MTR did not list the standard under which the Charpy testing was performed. Presumably, the MTR references the material standard that is requiring the CVN testing and that standard would state the standard covering the CVN test method (which, to be accurate, would be ASTM E23; A370 is a catch-all standard while E23 is particular for notched bar impact testing).

A simple phone call to the outfit certifying the MTR should be all you need, if you really are questioning whether the proper testing was performed.

Now, if you honestly believe the CVN testing was not performed correctly or that the results reported are not representative of the material, then re-testing is called for. But, to require re-testing just because the MTR does not state that the testing was performed in accordance with A370 is a bit overbearing.

While I have had customers call and request our MTRs state that the Charpy testing was performed in accordance with ASTM E23, but I have never seen anyone ask for re-testing just because this was not stated on the MTR.

rp

 

[jwhit]

This is twice today that I'm on the same page as Redpicker. Normally, you do not have to include the testing spec. on the MTR. If you are working to ASTM or ASME it is at the least implied that the testing will be done to A370/E23 unless otherwise specified by your customer, in which case it will probably be to one of the EN specs. The only one I know of that would be a problem is the now obsolete ISO 148 standard. It's replacement acknowledges A370/E23 as acceptable.

 

[TerryR1]

Thanks fellas. Yes industry standard appears to assume compliance with A370/E23. Thanks for sharing your experience, and pointing out the ASTM material specs include above.

So for other materials ie 4130 (not astm), now my issue is whether I leave "Charpy test per ASTM A370..." as a requirement on my material POs. If I take if off, then I'm assuming liability if we get some bad material. If I leave it on, then I have to educate my suppliers that all their material (probably) meets this spec.

I'm not seeing where ISO 148 is obsolete? It did replace EN 10045.

 

[redpicker]

Yes, you should leave "Charpy Testing per ASTM A370" on your purchase orders. You should also call out the test temperature and specimen size, along with the absorbed energy requirement. Failure to specify any of these could easily result in your receiving material that does not meet your expectations.

Actually, all of this information belongs in a material specification, and your PO should just refer to that specification. If there isn't an applicable ASTM or other globally recognized standard, then write your own. Yes, it is acceptable to just have the PO state your requirements, but if this information has to be repeated every time you issue a new PO, you run the risk of mistakes occurring. That is the purpose of the written specification. It also helps keep the PO clean and easy for your vendors to understand. Generally, the people who write up the PO's on your end and accept the PO's on your vendor's end are not the people in the organization with the highest technical knowledge, so simple mistakes (such as a minimum yield strength of 1050000 PSI) may simply get passed through the system without anyone noticing. By the time the mistake is found, it may be too late.

rp