During 2017 the SMDI Bar Steel Fatigue sub-committee continued work on numerous studies, test protocols, as requested by the committee members who represent key ground vehicle OEMs and suppliers. The committee continues to concentrate test efforts on those steel grades and process combinations used in safety critical components. Accomplishments in 2017 include:
- Phase XI of the test protocol was completed. The material tested in this phase was SAE 8620 with carburized case depths of 5% (shallow) or 10% (deep). The material was subjected to the standard axial fatigue tests and additionally to four-point bending fatigue tests to compare and correlate results. As in previous phases both the axial and bending tests included overload stress conditions. As part of the study, members of the committee also provided residual stress measurements of selected samples.
- The team also completed Test Phase XV. DIN 16MnCr5 steel at carburized case depths of 5% and 10% was evaluated. As in Phase XI the material was tested in both axial and bending fatigue to compare and correlate results. As part of the study a member of the committee completed failed sample fracture analysis to track the location and cause of fatigue failures.
- Rotating bending fatigue tests were completed on SAE 8620 and DIN 20MnCr5 steel as part of Test Phase XIII. These tests were run to compare and correlate results to previous axial fatigue results.
- The sixth update of the on-line publically available database to 164 steel/process iterations. An additional 30 iterations are being held confidentially to the committee members who fund the research. These iterations represent 13 completed test protocols.
Further blog discussions on all of these test phases will be completed at a later date when the data becomes available to the public. If you are interested in these results earlier, consider becoming a committee member. For more information visit www.autosteel.org or contact David Anderson.