Totomak Makine ve Yedek Parça Sanayi Tic. A.Ş.
Induction surface hardened low alloyed medium carbon steels are frequently utilized in essential automotive and machine applications that demand high fatigue resistance. The right combination of hardening depth and the magni-tude and distribution of residual compressive stresses in the surface layer de-termines the fatigue behavior of induction hardened components to a large extent.
Axles are connected within vehicles to provide two vital functions:
•Carry torque from the engine to the wheels via a planetary gear arrange-ment,
•Keep the wheels in relative alignment with each other and the vehicle's body. The circular motion of the drive wheels is maintained in most non-commercial vehicles by axle shafts, which are an essential component of the rear axle.
Two axle shafts, which are used as powertrain element in construction vehi-cles hardened with induction heat treatment with SAE 4140 material stand-ard, were broken during operation. In this study, 2 failed axle shafts and 2 non-failed axle shafts were compared in order to determine the reason for the breakage.
The parts were cut from 3 different regions and the images of the pieces were taken with a CARL ZEIZZ NEOPHOT 32, NIKON SMZ 1500 light mi-croscope. The microstructure and hardened case depths of the parts were checked.
In microstructure images, it was seen that the structure was not completely homogeneous, However, it was un-derstood that this was not the cause of the failure. And also, It was determined that the grain size of G1 and G2 shafts was rougher than T1 and T2.
T shafts have been observed to have a low hardened case depth in the spline area. In the conical end area of the shafts, the prior austenite grain was found to be considerably coarser because the edge above the groove was overheat-ed. Under the grove the inappropriate wave with decreasing of case-hardened depth have observed.
It was determined that the reasons for the failure of the parts were low hard-ened case depth. The effective case depths of the failed T-parts were found to be 6 mm, and the non-failed G-parts were greater than 8 mm.
As a result of the studies, it was determined that the reason for the breakage of the parts was low hardened case depth caused by heat treatment
Primary Language | English |
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Subjects | Engineering |
Journal Section | Research Articles |
Authors | |
Early Pub Date | December 16, 2022 |
Publication Date | December 30, 2022 |
Published in Issue | Year 2022 Volume: 1 Issue: 4 |