Gao J.-T.,University of Science and Technology Beijing |
Li S.-Q.,University of Science and Technology Beijing |
Zhang Y.-L.,University of Science and Technology Beijing |
Zhang Y.-T.,University of Science and Technology Beijing |
And 2 more authors.
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2012
The characteristics of dust obtained from different steelmaking enterprises were systematically studied. A new process for separating and enriching zinc from metallurgical dust at low temperature was developed. Based on the volatilized thermodynamics analysis and dynamics reduction experiment of pure ultra-fine ZnO, the experimental study on non-molten reduction and recovery and enrichment of zinc in dusts was carried out. The results show that zinc oxide is reduced to metallic zinc, using high-purity CO or H 2 as the reducing agent at 800-900°C, and the de-zincing rate is over 99%. The collected gaseous reduction products are washed to get rid of K, Cl and other elements, then the enrichment, called Zn-rich material, is obtained with the content of Zn up to 90%. At the same time, the dusts are reduced at the state of non-molten because of low temperature, and the metallization of Fe in product of solid-state reduction is as high as 90%. Furthermore, the solid-state high-purity iron can be directly separated physically.
Hu X.,Hubei Xin Yegang Steel Co. |
Chen J.-N.,Hubei Xin Yegang Steel Co.
Beijing Keji Daxue Xuebao/Journal of University of Science and Technology Beijing | Year: 2012
To solve the problems of rolling along the line of long thick-walled drill collar tubes (the ratio of outer diameter and wall thickness (D/S)≤3.7) in Assel mill and promote the uniform of wall thickness, a series of technical measures were carried out, such as optimizing the billet properly, distributing the deformation reasonably, adjusting the parameters of piercer and Assel mill, and optimizing the pass parameters and the speed setting of the reducing mill. The length of finished drill collar tubes completely meets the standard, and the uniform of wall thickness in transversal and longitudinal directions reaches the higher standard. The user experience shows that, the use of tubes as raw materials is better than that of bars in saving materials, promoting the pass rate, improving the efficiency, and reducing the tool consumption.
Zhang Z.C.,Hubei Xinyegang Steel Co. |
Zhou L.X.,Hubei Xinyegang Steel Co. |
Ruan L.H.,Wuhan University of Science and Technology |
Qiu J.A.,Wuhan University of Science and Technology |
And 2 more authors.
Energy Materials 2014, Conference Proceedings | Year: 2014
The effect of tempering temperature on the low temperature toughness of the Cr-Mo alloyed pressure vessel steels containing 0.54 % and 1.55 % Si during the normalizing and tempering heat treatment was investigated by optical and scanning electron microscopes. The bainite-ferrite dual phase was obtained in both steels. As the tempering temperature increased from 650 °C to 700 °C, the average Charpy absorbed energy (-30 °C) was decreased from 158 J to 91 J in the 0.54 % Si steel whereas it was decreased from 83 J to 31 J the 1.55 % Si steel. The low temperature toughness decreased with increasing tempering temperature, which was probably attributed to a sharp increase of the ferrite volume fraction. Results also showed that the silicon content had much influence on the low temperature toughness.
Hu F.,Hubei Xinyegang Steel Co. |
Zhou L.,Wuhan University of Science and Technology |
Zhang Z.,Hubei Xinyegang Steel Co. |
Zhang G.,Wuhan University of Science and Technology |
Wu K.,Wuhan University of Science and Technology
Materials China | Year: 2015
Micro- and nano-structured steels are high-performance structural steels which have a unique combination of ultra-high strength, high ductility and good toughness. The ultra-high strength of these steels is attributed to sub-micro or nanosized ultra-fine martensitic and bainitic structures, while the ductility and toughness is associated with retained austenite. Therefore, it has become an important scientific problem to achieve fine microstructure and excellent mechanical properties by means of adjustment of the retained austenite through controlling the chemical composition and heat treatment etc. Based on the strengthening and toughening mechanism of iron and steel, the refinement of microstructure and reasonable regulation of hard and soft phases are important way to develop a new generation iron and steel material. The recent development of micro- and nano-structured super bainitic steel, Q&P and Q-P-T steels are reviewed and analyzed from the alloy design, heat treatment process and the relationship between microstructure and mechanical properties, wear properties and fatigue properties. Finally some issues on the micro- and nano-structured ultra high strength steels are pointed out for further research and development. ©, 2015, Materials China. All right reserved.