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Xiao J.-G.,University of Science and Technology Beijing | Xiao J.-G.,Shaoguan Iron and Steel Group Co. | Wang F.-M.,University of Science and Technology Beijing | Cheng H.-J.,University of Science and Technology Beijing
Jinshu Rechuli/Heat Treatment of Metals | Year: 2010

Based on metallographic, scanning electron microscope and EDS analysis methods, the surface microcracks of continuous cast slabs and the hot-rolled plates of Q345B low alloy steel were studied. The results show that copper, arsenic and tin segregates at grain boundaries, oxidation layer and microcrack surface in the continuous cast slabs and steel plates. The effect mechanism of residual elements on surface microcracks are analyzed, some counter-measures for preventing and controlling surface microcracks are proposed.

Geng M.-S.,Mcc Capital Engineering and Research Incorporation Ltd | Geng M.-S.,University of Science and Technology Beijing | Wang X.-H.,University of Science and Technology Beijing | Zhang J.-M.,University of Science and Technology Beijing | And 2 more authors.
Kang T'ieh/Iron and Steel (Peking) | Year: 2010

Influencing factor of the blow hole defect in continuous casting slab and hot rolled plate were analyzed. The main reason of surface blow hole defect in continuous casting slab is that the argon gas insufflate the mold from the upper nozzle, argon sealing and submerged entry nozzle cannot float effectively. The argon blow hole was captured by solidified continuous casting slab shell and induced the surface blow hole defect in continuous casting slab. The blow hole mostly distributed to the wide-face shell edge near the narrow side position. The quantity of blow hole in the center of wide-face and the 1/4 of wide-face shell is few. The surface blow hole defect in continuous casting slab and hot rolled plate can be eliminated by utilizing no argon blowing.

Wu Y.-M.,Shaoguan Iron and Steel Group Co. | Shi S.-P.,Shaoguan Iron and Steel Group Co. | Song W.-Y.,Guangdong Entry Exit Inspection and Quarantine Bureau
Yejin Fenxi/Metallurgical Analysis | Year: 2012

This paper reported the method for the determination of Si, P, Cu, S, Mn, As, Ti, Sn, V, Cr, Ni, Mo and Al in cast iron by X-ray fluorescence (XRF) spectrometry with power pressed method. The sample was pretreated with low-temperature annealing method, and during the sample-molding process, ten drops of mixed solution with certain ratio of rosin and acetone in the adhesive layer. The method selected fifteen national/ministerial grade and self-made standard samples to prepare a standard series of sample for establishing the calibration curve. The blank sample coefficient correction method was employed for calibrating the interference resulted from the overlaps of spectrum lines. Theoretical alpha coefficient and empirical coefficient was combined to overcome the sample spectral interference and matrix effect. The results of the proposed method were consistent with those of inductively coupled plasma spectrometry and spark source optical emission spectrometry.

Huo X.,Jiangsu University | Guo L.,Jiangsu University | He K.,Shaoguan Iron and Steel Group Co. | Huang R.,Shaoguan Iron and Steel Group Co.
Advanced Materials Research | Year: 2012

In order to shorten the spheroidizing annealing time, the effects of annealing time on microstructure and hardness of GCr15 have been researched by using OM, SEM and Vickers hardness tester. The original microstructural constituent of bearing steel is pearlite and cementite. Prolonged time at 805°Cwill decrease the number and increase size of cementite particles. After incomplete austenization at 805°C, prolonged time at 720°C induces increase of particle size, and uniform distribution of divorced pearlite. The hardness of specimens treated with different spheroidization process fluctuates around 200HV, and is equivalent to that with conventional spheroidization process. It is realizable to shorten the annealing time on the premise of good quality of bearing steel. © (2012) Trans Tech Publications, Switzerland.

Zhou C.-G.,University of Science and Technology Beijing | Li J.,University of Science and Technology Beijing | Shi C.-B.,University of Science and Technology Beijing | Yu W.-T.,University of Science and Technology Beijing | And 3 more authors.
High Temperature Materials and Processes | Year: 2016

Effects of temperature and slag composition on dephosphorization in a 120 ton top-bottom combined blown converter steelmaking process by double slag method were studied. The slag properties were determined by scanning electron microscope-energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD). The results show that the transition oxidation temperature between dephosphorization and decarbonization Tf is not the favorable temperature for the first deslagging. The optimum first deslagging temperature is confirmed to be approximately 1,673 K which is about 70 K higher than Tf. High melting temperatures phases (such as 3CaO·SiO2) in the slag with high basicity and MgO content are unfavorable to the dephosphorization. The optimum process condition for dephosphorization at the first deslagging in present work is approximately 1,673 K in temperature, 2.0 in slag basicity, 6 and 17 mass% in MgO and T.Fe content, 6 mass% ≤ MnO content. © 2016 by De Gruyter.

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