This is a report prepared by the
foundry or
steel mill that gives you the
chemical composition and
physical properties of a
material. Often shortened to CMTR, MTR, or Mill Certs, these reports are provided to the users of a metal as verification that the material is of a certain grade. Of course, the material must bear a
heat number or some other kind of cross-referenceable marking to positively identify that the paper refers to that pour or melt of material. To verify a mill test report, you would need to do a
PMI or
positive material identification.
The chemical analysis gives the amount of various metals and elements within the material under consideration to an accuracy of a thousandth of a percent. For example, I have one here that tells me that a particular valve body casting has 0.040% Carbon, 1.100% Manganese, 1.150% Silicon, 18.310% Chromium, 10.370% Nickel, 2.120% Molybdenum, 0.028% Phosphorus, 0.018% Sulphur and the remainder Fe. Put your hand up if you identified it as ASTM A351 grade CF8M stainless steel.
The physical properties listed on a CMTR are Tensile Strength, Yield Strength, % elongation, and hardness. A test specimen is poured and destructively tested in order to obtain these values and usually these values cannot be verified without destroying some part of the material you have on hand.