We are trying to verify the honesty/integrity of the mill, so asking them for more samples wouldn't be a good solution. Thanks to everyone for the input, I will have to get another test coupon to have a longitudinal test performed.
Ed, the UTS, elong, and ROA are much closer than the yield. They are all about 5%-7% low, compared to the yield being around 15% low.
We are using drops from our machine shop to send to our lab, so unfortunately we don't have alot of extra material to send off for multiple tests.
Good point Bestwrench, the original mill MTR is longitudinal, and the lab was transverse. Is there a general rule that I can use to relate the two, or do I need to send another specimen requiring longitudinal?
The condition is normalized, hardened, and tempered. Both the mill's MTR and the independent labs certificate state the testing was performed at the half radius.
We are running independant testing on materials that we recieve to check the accuracy of our vendors' MTRs. Obviously we don't expect every number on the original MTR to match the results of the independant testing 100%, but how much variation should I expect?
For example, we sent a 4130 bar...
