Structural and wear assessment of H11 die steel as a function of tempering temperature

Abstract

H11 steel is widely used in helicopter landing gears and dies for extrusion and forging. The property of H11 steel can be enhanced by several types of heat treatments for a long life span and improved design accuracy. In the present work, an attempt is made to study the effect of the tempering cycle on the two-body abrasive wear behavior. The structural characterization of hardened and tempered specimens was carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Two body abrasive wear tests were carried out using silicon carbide abrasive with a systematic and simultaneous variation of test parameters. The different tempering temperatures used in the present investigation are 200 °C, 400 °C and 600 °C. The result showed that the wear mechanism like (ploughing and micro-cutting) in each condition was dominated by the types of phases present in the material and their morphology. The wear debris was flaky and ductile. There was the presence of a small amount of SiC particles from the abrasive wear paper in wear debris for high load (40 N) wear tests. The wear debris particles were relatively finer in as-quenched condition and low tempering temperature (200 °C), while those were large for samples tempered at 400, 600 °C and fully annealed condition. The wear debris analysis through micrographs and iron oxide particles were not detected in XRD patterns.