The Effect of Carburization and Repeated Heat Treatment with Different Solutions on the Fatigue Resistance of Medium Carbon Steel

Many mechanical parts are exposed to failure as a result of mechanical stresses for design or metallurgical reasons, and the phenomenon of fatigue represents the largest area and reaches (90%) of the faults of engineering parts that are subject to periodic stresses. The risk of fatigue failure occurs without warning, so the phenomenon of fatigue resistance has taken up a large part of the research and studies concerned with the dissolution of metals. This article aims to study the effect of fatigue resistance of ASTM 1050 steel. Carbonation, repeated quenching at different temperatures (780 & 770℃) using seven different solutions, and tempering at repeated tempering after each quenching at temperatures (230 & 250℃). The stress resistance of all the studied samples decreases after the second cooling in distilled water, with the exception of the samples that were initially quenched with the same solution and then quenched again. This is one of the most significant findings. Another finding is that following a second chilling in distilled water-based solution, the resistance to fatigue stress rises, increasing by up to (8.5%) in comparison to samples that were first quenched in the same solution then diluted.