Pearlite

About: Pearlite is a research topic. Over the lifetime, 6028 publications have been published within this topic receiving 65695 citations.

Influence of Deformation on Transformation of Low-Carbon and High Nb-Containing Steel During Continuous Cooling

Abstract: The effect of deformation in the non-recrystallization region on the phase transformation for a low-carbon and high Nb-containing steel with coarse austenite grain size was investigated by means of dilatometric measurement and microstructure observation. The results show that with increasing the cooling rate, both the transformation start and finish temperatures measured by dilatometer are decreased, and the corresponding microstructure is transformed from ferrite and pearlite to full granular bainite gradually. The dynamic continuous cooling transformation diagram was plotted according to the dilatometric measurements and microstructure observations. Dilatometric measurements also show that the transformation start and finish temperatures of the test steel rise with increasing strain, strain rate and deformation temperature, and the reasons are discussed.

Deformation, Wear and Microstructural Evolution of Nano-structured Pearlite Under Repeated Contact Sliding

Abstract: Refinement of lamellar spacing down to a few nano-meters in pearlitic steels offers a unique combination of high strength and toughness. The present work pertains to the tribological response of nano-structured pearlitic steels with varying lamellae spacing under repeated frictional sliding using a conical diamond tip. The wear response has been quantified through the friction, volume of groove formed by the indenter and deformation-induced structural changes with number of passes of sliding. Results indicate that the initial microstructure and mechanical properties have a profound impact on the wear resistance since these factors also govern the microstructural adaptability under repeated sliding. The finest lamellar spacing pearlite shows the least wear volume, lowest friction coefficient and the smallest deformation-affected zone.

Microstructure evolution and mechanical property enhancement of high-Cr hot work die steel manipulated by trace amounts of nano-sized TiC

Abstract: Simultaneously increasing the strength and ductility of hot work die steels is of significant interest for broad applications. The in-situ development of a nano-phase in steels is a promising method for achieving this objective. However, little success has been reported so far. In this study, trace amounts of TiC nanoparticles were successfully introduced into a high-Cr hot work die steel (HHD) through an innovative method using a nano-TiC/Al master alloy. Upon adding 0.02 wt% nano-TiC, an incompletely recrystallized ferrite phase was observed in the HHD containing nano-TiC. Moreover, more globular pearlite was distributed at the ferrite grain boundaries in the HHD with nano-TiC than in the unmodified HHD. The added nano-TiC provided nucleation sites for γ-Fe dendrites and prevented γ-Fe growth during solidification and an austenitizing heat treatment. Furthermore, it noticeably increased the precipitation of more uniform nanoscale chromium carbides and significantly refined the carbides in the HHD during quenching and tempering. Finally, adding nano-TiC simultaneously enhanced the strength and toughness of the HHD. After quenching at 1353 K and tempering at 833 K, the yield strength, tensile strength, tensile strain, and impact toughness of the HHD with nano-TiC were 1330 MPa, 1620 MPa, 14.4 % and 460 J/cm2, respectively, which are all higher than those of the HHD without nano-TiC.

Ductile cast irons: microstructure influence on fatigue crack propagation resistance

Abstract: Microstructure influence on fatigue crack propagation resistance in five different ductile cast irons (DCI) was investigated Four ferrite/pearlite volume fractions were considered, performing fatigue crack propagation tests according to ASTM E647 standard (R equals to 01, 05 and 075, respectively) Results were compared with an austempered DCI Damaging micromechanisms were investigated according to the following procedures: - “traditional” Scanning Electron Microscope (SEM) fracture surfaces analysis; - SEM fracture surface analysis with 3D quantitative analysis; - SEM longitudinal crack profile analysis - Light Optical Microscope (LOM) transversal crack profile analysis;

Changes in the macrostresses and microstresses in steel with fatigue

Abstract: The residual stresses in both the ferrite and cementite phases of fatigued 1080 steel specimens with pearlite, spheroidite and tempered martensite microstructures were measured using X-ray diffraction giving both the macrostresses and microstresses. Specimens with no initial stresses showed little changes with fatigue. Specimens with initial macrostresses and microstresses showed fading of the stresses, the fading being slowest for the strongest microstructure. Hydrostatic microstresses are present after heat treatment owing to the differential thermal properties of the cementite and ferrite.