Investigation of the Wear Behavior of Martempered 30 MnB5 Steel for Soil Tillage

Abstract

The objective of this experimental study was to determine the wear resistance of moldboard plowshares produced from 30 MnB5 steel that were treated with different martempering conditions. The microstructures, the hardness distributions, and the wear behavior of the martempered 30 MnB5 steel were determined and compared with conventionally heat-treated samples in laboratory conditions. The wear losses of all martempered samples were less than that of the conventionally heat-treated samples in laboratory conditions, especially at the end of a longer-term wear experiment. The martempering process in which the steel was austenized at 960C for 35 min, held at 350C for 10 s in a salt bath, and then cooled in air produced the best results for decreasing wear loss in laboratory conditions. The martempering treatment that resulted in the lowest wear weight loss in pin-on-disc tests was selected for further testing in field conditions. The field used for the experiment was flat and free of crop residue with a uniformly dispersed soil type (sandy and sandy loam). A reversible plow was used to measure the wear. The abrasive wear losses were determined by measuring the plowshare's weight and dimensions before and after tillage. By achieving a more uniform hardness distribution, the lath-type martensitic and bainitic microstructure of the martempered plowshares significantly increased their wear resistance. The martempering process decreased the wear weight loss by 40.8% and the wear dimension loss by 38.5% compared to conventionally heat-treated plowshares in field conditions.