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| Characteristics of Inclusions in High Sulfur Gear Steel SAE8620H Hot-Rolled Round Bar |
| ZHANG Hai-quan1,XIE You1,CHENG Guo-guang1,CHEN Lie2,KOU Yu-shan2 |
1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
2. Xining Special Steel Co., Xining 810000, Qinghai, China |
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Abstract The size, quantity, distribution, morphology and composition of inclusions in cross section and longitudinal section of high sulfur gear steel SAE8620H hot-rolled round bar produced with the EAF-LF-CC process were synthetically investigated by means of optical microscopy, scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the inclusions are mainly MnS and oxide-sulfide duplex inclusions formed by MnS or (Ca,Mn)S precipitating upon Al2O3 and MgO-Al2O3; the number of inclusions increases and the ratio of oxide-sulfide duplex inclusions decreases from surface to center of high sulfur gear steel SAE8620H hot-rolled round bar; the diameter and the aspect ratio of inclusions in cross section are mainly less than 2μm and 3 respectively;In the longitudinal section, the average length of inclusions is 11μm, the average length of inclusions at surface is less than that of center by 3μm and the ratio of spindle inclusions is only 30%.
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Received: 21 September 2012
Published: 18 July 2013
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2013, Vol. 48 
