Microstructure evolution of GCr15 in cold ring rolling and following heat treatment

Abstract

The influences of deformation degrees on the microstructure evolution of GCr15 steel in cold ring rolling and following heat treatment (quenching and temper) are investigated in this paper. As the deformation is uneven, microstructure at the outer surface, middle place and inner surface on the cross-section of the ring is selected for the study. The microstructure is characterised by scanning electron microscopy, optical microscopy and X-ray diffraction. The [Formula: see text] transformation is studied with differential scanning calorimetry, and the hardness is examined by Vickers hardness tester. The results show that the deformation is severe on the outer surface but slight on the middle place and inner surface. A large degree of deformation leads to the acceleration of carbide dissolution, the grain refinement and the increase of hardness. In addition, the deformation results in the decrease of [Formula: see text] transformation temperature according to the differential scanning calorimetry data.

Effect of Hot Rolling on Microstructural Evolution and Wear Behaviors of G20CrNi2MoA Bearing Steel

“…Previous experiments have confirmed the significant effect of cold ring rolling on the microstructural evolution of GCr15 bearing steel during quenching and tempering [23]. The main reason for this effect is that the deformed initial microstructures lead to the refinement of austenite grains and the accelerated dissolution of carbides in the subsequent austenitization step [24], thus affecting the microstructure transformation during quenching and tempering [25,26]. However, the influence mechanism of hot deformation on the microstructural evolution of carburized steel during subsequent heat treatment may be more complex.…”

Simultaneous Improvement of Toughness and Fatigue Life in a Typical Ultrahigh Strength Steel by a New Deep Cryogenic Treatment Process

“…The primary factors affecting the fracture of carbon steel are both the content and morphology of martensite, RA, and carbides. [31][32][33][34] Thus, the causes of the varied mechanical properties from the different treatment processes were analyzed through the microstructures. In the following, the process of traditional heat treatment (QTT), the process with the worst mechanical properties (QCTT), and the process with the best mechanical properties (QTC) will be discussed in detail.…”

Obtaining ultrafine spheroidized carbides by combining warm deformation with divorced eutectoid transformation in GCr15 bearing steel

“…However, based on the observed microstructure and grain uniformity, it can be assumed that the appropriate deformation temperature is located at the temperature range of 700°C∼720°C. Furthermore, according to the equations (1), (2) and XRD analysis shown in figure 6, the dislocation density and the volume fraction of carbides in ferrites for the specimens deformed at different temperature can be determined. Normally, the dislocation density increases with the decrease of deformation temperature.…”

“…GCr15 steel is a kind of traditional high carbon chromium bearing steel, which is widely used in railway components, die making, shipbuilding, aerospace and automotive applications [1]. Due to the poor forming performance of GCr15 steel with the lamellar pearlite, it is difficult to produce complex components by cold forming [2], which limits the use of high carbon steel. For this reason, spheroidization annealing treatment (SAT) is used to obtain the spheroidizing microstructure in which not only helps to restore the ductility, but also helps to maintain the ferrite grain size and reduce deformation resistance [3,4].…”