A comparison of microstructure and mechanical properties of low-alloy-medium-carbon steels after quench-hardening

Abstract

The microstructural characteristics of three medium carbon steels, namely MnCrB, NiCrSi and NiCrMoV containing steels, have been investigated when the steels were hardened by quenching in water or oil from different austenitisation temperatures (i.e. 850, 900 and 950 °C). The microstructure was characterised using optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, and X-Ray diffraction technique, whereas the mechanical properties were measured by Vickers hardness testing, V-notched Charpy impact testing and tensile testing. The microscopy observations suggested a fully martensitic microstructure, whereas martensite was considerably finer in NiCrSi and NiCrMoV steels compared to MnCrB steel. Moreover, the NiCrSi and NiCrMoV steels showed significantly higher strengths and lower ductility than MnCrB steel. The results suggested that the small additions of alloying elements and different prior austenite grain sizes were mainly responsible for the observed microstructural and mechanical properties variations.

Effect of Different Heat Exchange Zones on Microstructure and Properties of Ultra‐Heavy Steel Plate During Jet Quenching

“…In Figure a and b, it can be seen that the upper surface fracture in Z1 and Z2 extended along a particular crystalline plane. On the fracture surface, there were river patterns and a lot of plastic deformation tear ridges . The shape of equiaxial dimples on the tear ridges was small and shallow, indicating typical quasi‐cleavage fracture, which was attributed to the large number of large grains and the fine grain size (Figures a and b, 8a and b), which corresponded to good low‐temperature toughness (Figure b).…”

Real-time interface-tracking framework for the evolution of the phases during the quenching of the steel balls

“…Other factors additionally could alter the mechanical properties of the steel such as strain hardening [20], solute solution hardening/softening [21,22], precipitation strengthening [23]. The iron-carbon system the most important alloy utilized for engineering applications of steel [24], particularly when containing high density of dislocations with shorter average mean free path [25,26].…”

Comparison of Novel Low-Carbon Martensitic Steel to Maraging Steel in Low-Cycle Fatigue Behavior

“…The method of hysteretic energy model has been well used in the life prediction of many materials. The relationship between hysteretic energy and fatigue lifetime is expressed by the hysteretic energy model [35]:…”