Pearlite

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

The formation of austenite from mixtures of ferrite and cementite as observed by HVEM

Abstract: The detailed mechanism of the transformation of various mixtures of ferrite and austenite was studied byin situ experiments in a high voltage electron microscope. Various phenomena were observed which seemed to be controlled by the rate of carbon diffusion when the γ/α interface was curved. The effect of manganese was studied by using commercial steels. In agreement with theoretical predictions based upon the local equilibrium model, the dissolution of cementite in ferrite can be more or less prevented by manganese. The effect on the dissolution in austenite is smaller. The reaction from lamellar pearlite to austenite is more complex, the cementite lamellae providing carbon to the austenite but also acting as barriers.

The structure and properties of steel with different pearlite morphology and its resistance to abrasive wear

Abstract: Purpose: The analyse of pearlite morphology changes as a result of hot rolling process and isothermal annealing. Design/methodology/approach: Physical modelling of isothermal annealing for a transition point of 520-620°C was carried out using a Gleeble simulator. A scanning electron microscope was used for a quantitative evaluation of the microstructure. Findings: The obtained test results confirm that these methods can be effectively used in shaping the pearlitic structure and properties of the steel. During numerical simulation of a ride of a rail-vehicle through a switch, the load acting on a block section being part of the vehicle structure was determined. The load values were used in simulation of the resistance to abrasive wear, which was carried out in physical simulation. Practical implications: In physical modelling of tests of resistance to abrasive wear for the steel grade R260 after hot rolling and isothermal annealing it has been proved that this feature is a function of the steel structure and properties in the given operation conditions (load and slide magnitude). Abrasive wear of the rail steel is the more intensive, the larger the load at a constant slide is. Originality/value: An advantageous pearlitic morphology of steel (block sections) with interlamellar distance in the order of 0.12-0.13 μm, ensuring hardness of about 340-350 HB, is facilitated by a hot rolling process combined with isothermal annealing.

Influence of austenitisation temperature on the structure and properties of weather resistant steels

Abstract: The influence of austenitisation temperature on the structure and properties of three experimental weather resistant steels has been studied. All these steels contain 1% Mn, 0.3% Ni, 0.47% Cr and 0.47% Cu. In addition, steel #1 has 0.1% C, 0.1% P, steel #2 has 0.1% C, 0.05% P and 0.024% Nb while steel 3 has 0.2% C, 0.054% Nb and 0.046% V. It has been found that the hardness, yield strength and tensile strength do not change significantly with austenitisation temperature over the range 900–1200 °C for steel #1 but they increase considerably when austenitised above 1000 °C for steels 2 and 3. Similarly, the ductility decreases with increasing temperature of austenitisation. All the steels austenitised up to 1000 °C exhibit sharp yield points. None of these steels shows sharp yield point after 1200 °C. At 1100 °C, however, sharp yield points were observed in steels 1 and 2. There has been a noticeable change in optical microstructure. In steels 2 and 3 the pearlite is gradually replaced by granular bainite when austenitised above 1000 °C. The transmission electron microscopy study reveals that the granular bainite consists of acicular ferrite and martensite/austenite constituent.

Microstructure and Texture of Strip Cast Grain‐Oriented Silicon Steel after Symmetrical and Asymmetrical Hot Rolling

Abstract: A grain-oriented silicon steel as-cast strip was produced by twin-roll strip casting. Then the as-cast strip was symmetrically and asymmetrically hot rolled, respectively. The microstructure and texture evolution was investigated by a combination of optical microscopy, X-ray diffraction, and electron backscattered diffraction methods. The microstructure of the as-cast strip consisted of ferrite matrix and martensite, and the texture was characterized by pronounced {001} 〈0vw〉 fiber texture in the outer layers and nearly random texture in the inner layers. After symmetric hot rolling, the microstructure was composed of deformed ferrite grains, proeutectoid ferrite grains and pearlite. The texture was characterized by pronounced {001} 〈0vw〉 fiber texture in the outer layers and mild γ-fiber texture in the inner layers. By contrast, when asymmetric hot rolling was applied, considerably dispersive proeutectoid ferrite and pearlite and relatively strong Goss texture were observed, together with strong {001} 〈0vw〉 fiber texture in the outer layers.