Charpy test
Charpy test
(OP)
I just recently started working in a steel Foundry, I'm not familiar with the Charpy Test. I have read some specs(asme sa352 for grade LCC and A-370. Recently we've seen failures in one of the tree test bars. The bars are being poured in a sandcasting mold. Would you know what could make them fail?
Thanks for the help! Mario
Thanks for the help! Mario





RE: Charpy test
RE: Charpy test
One of the other Question is, What other factors may contribute to the failure one test bar vs. th other? other than chemistry. Thank you for taking the time and patience to answer and most of all thank you for sharing your knowledge.
Sincerely, Mario E.
RE: Charpy test
RE: Charpy test
Assuming you are tesing at -50F per A352, for a good clean heat of steel, you should be getting 50 to 150 ft-lb. Although, even with good steel, the lower strength steels like LCC, LCB, etc. seem to get quite a bit more scatter in the results than higher strength steel like A487 Gr. 4B, for instance. Most important is to have P and S low in chemistry. Also take a look at your specimens before testing. Is the notch machined properly? Does is have the correct radius at the root of the notch. Does the notch have any tool chatter in it?
Good luck,
G Roberts
RE: Charpy test
Discontinuities such as shrinkage/porosity or macro-inclusions at the location near the notch.
Normalized and tempered condition rather than quenched and tempered condition. Q&T gives much better impact properties than N&T.
Sulfur and phosphorus levels greater than 0.015wt% each.
AlN embrittlement large dull facets on fracture.
Improper heat treatment- not austenitized properly or tempered properly.
Hope this helps
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