The quality assurance system at American Metal Treating incorporates the latest instrumentation and testing methods to maintain the highest levels of quality and efficiency. Test equipment includes three Rockwell hardness testers, a Wilson gear hardness tester, a Krautkramer Mic-10 portable hardness tester, and a Tukin micro-hardness tester to certify effective case depths. Our investment in such equipment ensures that exact specifications are met on all orders.
Proper material selection is critical in ensuring a proper induction hardened part. Medium carbon steels (.4-.5) are necessary for good hardenability. Pre-heat treated alloys such as 4140, 4340, 4150 provide the best results, particularly on gear teeth. Such material pre-heat treated to 280-320BHN can achieve a final hardness ranging from 55-60RC. Annealed materials sometimes provide non uniform hardening.
The following are approximate case depths obtainable by induction hardening of gear teeth. It is assumed that the material is 1045 to 8660, and has been pre-heat treated to refine the grain structure. These are guidelines only; and in no way ensure that a particular case is adequate for the gear application.
Case depths can only be certified after destructive testing.
Magnetic Particle Inspections
AMT employs and trains certified magnetic particle inspectors. This training allows us to 100% inspect parts for surface linear discontinuities and certify that parts are crack free. We use the prepared bath spray/magnetic yoke method for all magnetic particle inspections.