Papers by Keyword: Interlamellar Spacing

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Authors: Xing Jian Gao, Zheng Yi Jiang, Dong Bin Wei, Bu Yung Kosasih, Si Hai Jiao, Deng Fu Chen
Abstract: The dry sliding wear behaviour of the full pearlite in a novel bimetal consisting of low carbon steel and hypoeutectoid steel has been studied by means of pin-on-disc type wear tests at room temperature. Thermomechanical treatments were performed on the bimetallic samples to obtain different interlamellar spacings. It was found that interlamellar spacing decreased with an increase in plastic strain to a great extent initially and followed by a lower extent of decrease. This decrease not only increases the hardness and strain hardening capacity of the fully pearlitic microstructure, but also is in favor of stabilizing the friction coefficient during sliding process. The observations of wear tracks show that delamination dominated the wear process when interlamellar spacing is higher than 200 nm, while pronounced oxidational wear occurred with interlamellar spacing below 200 nm.
Authors: Jia Qi Zhang, Yi Long Liang, Song Xiang, Xiao Di Yang, Ming Yang
Abstract: The effect of the heat treatment process parameters on the mechanical properties and microstructure of SWRS82B wire rods were investigated. Specimens were austenitized at 850°C~900°C and held at 500°C~600°C. The results show that the interlamellar spacing and the pearlite block size become finer with the decrease of the isothermal temperature. At the same isothermal temperature condition, the interlamellar spacing decreases with the increase of austenitizing temperature. The fine interlamellar spacing increases the yield strength and ultimate tensile strength.
Authors: Yi Long Liang, Song Xiang, Ming Yang, Yu Liang, Xiao Di Yang
Abstract: The mechanical properties and microstructure of SWRS82B wire rods and drawn wire were studied. Wire rods were austenitized at 850°C~900°C and held at 500°C~600°C. The results show that the finer interlamellar spacing results in the higher yield strength, tensile strength and reduction of area of the wire rod. Moreover, the finer interlamellar spacing does result in the higher yield strength of the drawn wire too.
Authors: Chao Lei Zhang, Ya Zheng Liu, Le Yu Zhou
Abstract: Specific features of plastic deformation and tensile failure of a spring steel with systematically various pearlite fineness obtained by isothermal transformation have been investigated by uniaxial tensile tests and electron microscopes. The results indicated that pearlite interlamellar spacing has an important influence on that. The tensile fracture surface is consisted of the center plastic fracture region and the edge brittle fracture region while the interlamellar spacing is within the range 140-280nm, and is a completely brittle fracture and no necking with the further increase in interlamellar spacing to 510 nm. The deformation characteristics of pearlite in the neck regions is mainly including S-shape bend, rotation and shearing. And the data obtained suggest that the interlamellar spacing within 140-280nm can ensure the plasticity for the steel.
Authors: Henrik Svensson, Torsten Sjögren
Abstract: The matrix structure formation of cast irons is strongly affected by the casting process where different alloying elements and cooling conditions are methods used to achieve the desired structure and performance of the material. In the presented study, six pearlitic grey cast irons have been analysed regarding how the pearlitic structure formation might be controlled. Different amounts of copper and chromium were added, ranging from 0.07 to 1.11 wt% and 0.08 to 0.60 wt%, respectively. Three different section sizes (Ø20, Ø45 and Ø85 mm) and three different cooling conditions through the eutectoid transformation were used to control the matrix structure formation. The three different cooling conditions were achieved by shake-out at 950°C and cooling in air or furnace, or by keeping the casting in the mould. The present paper focuses on the pearlite appearance, since it strongly affects the mechanical properties. The analysis shows that the refining effect of Cr is much stronger than that of Cu. Comparing the low alloyed base melt with the ones alloyed with Cu and Cr, it is seen that additions of 0.75 wt% Cu refines the pearlite by approximately 10%. Keeping this Cu level constant and adding Cr, it is observed that an addition of ~0.6 wt% refines the pearlite by another 20%. The most potent refining effect of Cr is achieved by additions up to 0.35 wt%. Keeping the Cr constant at 0.35% and changing the Cu content (0.35 to 1.10 wt%), almost no variation is observed in the overall interlamellar spacing. The eutectoid cooling rate most strongly affects the interlamellar spacing down to cooling rates of about -0.75 °C/s. At higher (i.e. lower value) cooling rates the interlamellar spacing is fairly constant. In addition to studying the interlamellar spacing, the graphite structure has also been analysed and evaluated concerning effects from the different casting variables.
Authors: Waldemar Wołczyński
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