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	2014 Vol. 49 No. 9
	Published: 2014-09-15

	1	DONG Hui, WANG Ai-hua, FENG Jun-sheng, ZHANG Qi, CAI Jiu-ju
		Progress and Prospect in Sintering Waste Heat Resource Recovery and Utilization Technology
		The waste heat recovery and utilization in sintering process is one of the means to decrease the energy consumption in sintering process. The current situations of waste heat recovery and utilization in sintering process at home and abroad are summarized, and the shortage existing in China is indicated. The power generation process of waste heat recovery and utilization for sinter in vertical tank and grade recovery and cascade utilization of waste heat from sintering process and are expounded emphatically from the perspective of process flow and technical features. The basic idea of the integrated process of waste heat recovery and desulfurization and denitration from sintering exhaust gas is given. It is pointed out that grade recovery and cascade utilization technology of waste heat from sintering process should be promoted actively, power generation process of waste heat recovery and utilization for sinter in vertical tank should be developed rapidly, and the concept of the integrated process of waste heat recovery and desulfurization and denitration from sintering exhaust gas should be deeply advocated so as to lay a technical foundation for China’s energy saving and emission reduction in sintering process.
		2014 Vol. 49 (9): 1-9 [Abstract] ( 1333 ) [HTML 0KB] [PDF 0KB] ( 59 )

	10	CUI Zhi-min, LI Yuan-liang, CHEN Ying, ZHANG Yu-zhu
		Surface Structure and Fractal Dimension Calculation of Pore in Low Silicon Sinter
		Two series of low silica sinter samples with different basicity and MgO content were prepared by sintering pot tests. XRD and TEM were used to characterize the structure and surface morphology of samples: a calcium ferrite and iron oxide content has undergone significant changes with the increasement of alkalinity and MgO content. Structure of pore ??changes more complex from columnar structure to Mesh erosion structure. Surface fractal dimension of sinter pore were calculated by monofractal software and surface fractal model respectively([Dss]and[Dsv]): Surface fractal dimension increases with the improvement of alkalinity and MgO content, [Dsv] and [Rsv] calculated by monofractal software are greater than [Dss] and [Rss] calculated by surface fractal model, which indicate that the surface fractal model can reflect more details, and has better correlationso. So surface fractal model can substitute traditional monofractal software to characterize the fractal structure of sinter pore surface, to solve the difficulties and limitations of the pore surface shooting.
		2014 Vol. 49 (9): 10-14 [Abstract] ( 1289 ) [HTML 0KB] [PDF 0KB] ( 85 )

	15	HU Bing,, HE Xin-hua,, WANG Zhao-cai,, YE Heng-di,, CHEN Yi-yuan,, SUN Ying,
		Wind and Oxygen Balance Based on Flue Gas Circulation Sintering Process
		Compared with ordinary sintering process, flue gas circulation sintering process has the advantages of energy savings and pollutant reductions. The change regularity of wind and oxygen balance during gas circulation sintering is focused on studying, and the emphasis is to further improve the flue gas circulation rate. It uses the method of combining theoretical calculation with measured results. The results show that flue gas of several bellows in the front and rear of sintering pallet with the characteristics of lower sulfur, higher oxygen content and higher temperature can be used as circulating flue gas, the flue gas and ring cold gas can be mixed uniformly by special gas mixing chamber. In the premise of insuring the volume percent of oxygen inlet gas exceeding 18%, flue gas circulation rate can reach to 43% by optimizing adjustment of main pumping air volume, air leakage rate and oxygen consumption of sintering. The theoretical guidance for the development of flue gas circulation sintering process can be provided.
		2014 Vol. 49 (9): 15-20 [Abstract] ( 1578 ) [HTML 0KB] [PDF 0KB] ( 65 )

	21	PAN Jian, SHI Ben-jing, ZHU De-qing, LI Xiao-bo
		High Proportion Sintering Performance of Canadian Iron Concentrate
		The sintering performance of Canada iron concentrate and metallurgical performance of sinter product was studied, the physic-chemical properties was investigated. The results show that the sintering indexes and metallurgical performance of sinter product both get some worse with the mixing rate of concentrate increasing from 24% to 42%. The permeability resistance of sinter bed increases from 857 Pa to 1 150 Pa ,the vertical sintering speed drops to 18.38 mm/min from 21.87 mm/min, the productivity declines from 1.14 t/(m2·h)to 0.93 t/(m2·h),the tumble index falls to 64.13% from 67.47%, the anthracite solid fuel consumptions increases to 70.42 kg/t from 62.46 kg/t, meanwhile, the reduction index(RI)and the reduction degradation index RDI＞3.15 mm for sinter product drops from 82.31% and 70.71% to 78.76% and 64.41%, respectively. This kind of concentrate was bad for granulating of mixture because of its major mineral-specularite and martite whose mineral surface has poor hydrophilicity-and unreasonable size composition, meanwhile, it is hard to generate enough liquid during sintering due to its dense and smooth surface and poor sintering capability-its softening temperature is more than 1 450 ℃. Therefore, poor granulating performance of Canadian concentrate leads to worse layer permeability then cause poor sintering performance, while high softening temperature results in the tumble index decreases when the mixing rate of concentrate increases.
		2014 Vol. 49 (9): 21-28 [Abstract] ( 1340 ) [HTML 0KB] [PDF 0KB] ( 46 )

	29	XIAO Hong， ZHANG Jian-liang， JIA Feng-juan， PANG Qing-hai，ZHU Guang-yue， ZHENG Chang-le
		Coal Blending Optimization for Blast Furnace Pulverized Coal Injection
		In order to investigate the reasonable blending plan of bituminit and anthrancite, the combustion and radicals of single coal as well as the combustion of blend coal were analyzed with thermal analysis device and FT-IR. The results indicated that the quantity of －OH was found to be reduced with deepening of degree of coalification, while that of －CH3 was found to be increased. A positive effect of relatively inferior combustion property bituminie on facilitating the combustion of anthranctie was noticed. Meanwhile, ideal combustion property of blend coal can also be obtained by the blending of bituminite and anthrancite with similar functional group structure.
		2014 Vol. 49 (9): 29-33 [Abstract] ( 1415 ) [HTML 0KB] [PDF 0KB] ( 66 )

	34	TENG Zhao-jie,, CHENG Shu-sen,, ZHAO Guo-lei,
		Influence of Chute Cross Section and Parameters on Burden Distribution for Blast Furnace
		As one of the important parts of the bell-less top, the parameters of the chute have great influence of the burden distribution. There are two kinds of chute used commonly, one is a semicircle and the other is a rectangle. Because of the different cross section shape, the movement of the particles in the chute was changed. At present there is less mathematical model about the burden distribution for rectangle chute. Trough analyzing the particles moved in the two kinds of chute, the influence of the chute cross section shape on the particle movement was discussed. The calculated result was compared with the experimental result. The results can guidance the chute cross section choose and the blast operation.
		2014 Vol. 49 (9): 34-37 [Abstract] ( 1218 ) [HTML 0KB] [PDF 0KB] ( 45 )

	38	ZENG Ya-nan, SUN Yan-hui, CAI Kai-ke, XU Rui
		Effect of RH Refining on Evolution and Control of MgO·Al2O3 Inclusion in Non-Oriented Silicon Steel
		Based on the practical production of non-oriented silicon steel, the evolution of inclusion type and the formation of MgO?Al2O3 inclusion were analyzed in the process of BOF→RH→CSP. The thermodynamic conditions for forming MgO?Al2O3 inclusion were discussed and the behavior of slag entrapment of molten steel was also simulated by CFD software during RH refining. The results showed that the value of [w([MgO])/w([Al2O3])] was in the range of 0.005?0.020 and no MgO?Al2O3 inclusion was observed at 20 and 30 min in RH refining; on the contrary, the value of [w([MgO])/w([Al2O3])] was in the range of 0.3?0.5 and the MgO?Al2O3 inclusion accounts for 58.5% of total amount of inclusions after RH refining. The compositions of slag were similar to the composition of inclusions; furthermore, the simulation results of CFD software show that the surface velocity was 0.57 m/s, which was greater than the critical velocity of 0.45 m/s. When the test steel was in equilibrium with slag, the [w([Mg])] was 0.000 24%?0.000 28% and [w([Al])] was 0.31%?0.37%, which was in theoretically calculated MgO?Al2O3 formation zone, thereby leading to formation of MgO?Al2O3 inclusion in steel. Thus, the MgO?Al2O3 inclusion was inhibited by reducing the quantity of slag entrapment and roughing slag in casting and controlling composition of slag and the MgO content in the ladle refractory.
		2014 Vol. 49 (9): 38-43 [Abstract] ( 1522 ) [HTML 0KB] [PDF 0KB] ( 54 )

	44	GUO Kai, YANG Sen-xiang
		Control of Nitrogen Content in Production of Clean Steel in Panzhihua Steel and Vanadium
		Considering as one of the important direction in the development of steelmaking technology, clean steel has extreme strict requirements on the content of impurity elements in steel. Meanwhile, due to larger ionic radius of nitrogen, low diffusion coefficient in steel and etc, it is difficult that nitrogen is gotten out of steel. In order to achieve the production of clean steel, improvements and research have been carried out, which contain optimizing raw and auxiliary material, converter smelting rules, refining ladle furnace technology, enhancing RH vacuum treatment equipments maintenance and refining continuous casting long nozzle in Vanadium Recovery and Steelmaking Plant of Pangang Group Panzhihua Steel and Vanadium Co.Ltd.,which controled the content of nitrogen efficiently. The Plant achieves the production of tire cord steel, IF steel and steel cylinders etc, and controls the TiN separate out from tire cord steel.
		2014 Vol. 49 (9): 44-48 [Abstract] ( 1172 ) [HTML 0KB] [PDF 0KB] ( 50 )

	49	LUO Lei, ZHAO Chang-liang, CHEN Yu-xin, YUAN Tian-xiang
		Control of Phosphorus Content for Refining Pipeline Steel X80 in 300 t Combined Blowing Converter
		An investigation was carried out on control of phosphorus content of pipeline steel X80 in Shougang Jingtang company. The reason for low phosphorus distribution ratio between slag and steel at the end of steelmaking was analyzed thermodynamically. In the meantime, the suggestions for adjusting composition of converter slag were given, and the optimum amount of slag to get the corresponding dephosphorization rate and phosphorus distribution ratio was determined. The results showed that, under the condition of existing technology, high MgO content in slag led to high melting point of the final slag and subsequently resulted in relatively large difference between the measured and theoretical phosphorus distribution ratio. The calculation indicated that, for the existing process, the amount of slag to be added into converter should be controlled in the range of 43?60 kg/t.
		2014 Vol. 49 (9): 49-54 [Abstract] ( 1148 ) [HTML 0KB] [PDF 0KB] ( 48 )

	55	SUN Hao, YANG Jing-ming, CHE Hai-jun
		Genetic Algorithm Based PP and Multi-Objective Optimization of Cold Continuous Rolling Schedules
		It is difficult to determine the weights of the comprehensive objective function in the multi-objective optimization. By both defining and quantifying of preference, 6 classes of preference functions were constructed by using numerical method, and a mathematics model of physical programming was proposed. Physical programming based on genetic algorithm has provided a more flexible and suitable interactive multi-objective optimization algorithm for engineers. Combining with multi-objective rolling schedules in a tandem cold rolling, in the optimization process of rolling schedules, the power distribution, the rolling energy consumption, and the slip factor were selected as objective functions. Physical programming based on genetic algorithm was applied to optimize. The results show that the optimized rolling schedule is better in realizing balance of each stand power, reducing the probability of the scratch, and greatly improving the surface quality and product quality of the plates.
		2014 Vol. 49 (9): 55-60 [Abstract] ( 1269 ) [HTML 0KB] [PDF 0KB] ( 78 )

	61	DING Shun-feng， YANG Li-po， YU Bing-qiang
		Intelligent Model for Evaluating Cold Rolled Strip Shape Based on Fuzzy Evaluation Rule
		Aiming at the problem of too few indexes for evaluating strip shape, based on the rule of fuzzy comprehensive evaluation, the intelligent shape evaluation model used online for cold rolled strip was established. First of all, the least square method of Legendre polynomials was used to recognize and record the information of macroscopic flatness and the primary flatness, secondary flatness, tertiary flatness, and quartus flatness in real time. Then, based on the traditional shape grading method, the rule of flatness fuzzy evaluation was established, and the online shape information of a 1 050 mm six-high cold rolling mill was comprehensively evaluated. The result of online shape comprehensive evaluation can provide important quantitative shape information for the closed loop shape control model and improve shape control effect and direct rolling process.
		2014 Vol. 49 (9): 61-63 [Abstract] ( 1353 ) [HTML 0KB] [PDF 0KB] ( 61 )

	64	WANG Chang, YU Yang, PAN Hui, WANG Lin, CHEN Jin, XU Hai-wei
		Influencing Factors and Formation Mechanism of Banded Red Scale Defect on Hot Rolled High Strength Steel Strip Surface for Mechanical Engineering Application
		Aiming at eliminating the banded red scale defect existing on the strip surface of high strength steel for mechanical engineering application, the microstructure of the cross section and surface at local defect position was observed through SEM and EPMA, and the uniformly-spaced characteristics related to the descaling system of hot rolling production line was studied. The results show that the scale thickness at the banded position is thicker than that of any other parts of the strip and there is a Si enrichment region between scale and strip. The correspondence of the spacing of banded scale and the spacing of the spray nozzles reveals that the existence of the banded scale defect is strongly related to the weak effectiveness of the finishing descaling process. The oxidization property of the given steel was analyzed through differential thermal analysis. The rapid growth of the scale thickness was found before the finishing descaling process in practice, and scale existing as Fe2SiO4 phase with strong adhesion ability leads to the difficulties of descaling process. Based on the study of the red scale formation mechanism, the control keys of hot rolling process and steelmaking have been proposed, which successfully removed the banded red scale defect.
		2014 Vol. 49 (9): 64-70 [Abstract] ( 1342 ) [HTML 0KB] [PDF 0KB] ( 49 )

	71	WANG Wen-yan， YUE Shen-wei， YUE Zong-ge， YUAN Hai-lun，XIE Jing-pei， LI Chang-yi
		Carbides of Cr5 Forged Steel Backup Roll Before and After Quenching and Tempering
		The effect of quenching (970 ℃) and tempering (540 ℃) on microstructure and style of carbide in Cr5 forged steel backup roll were studied by SEM and TEM. The [ΔH] and [ΔG] of formation and transformation were calculated by thermodynamic theories during this process. The results indicate that the matrix was pearlite, and the size of carbides was about 700~800 nm, complex hexagonal M7C3 and cubic M23C6 had the crystallographic orientation relationship of ([1120])K//([011])α, [0001]K//[011]α and (511)K//([011])α, [[116]]K//[[011]]α with ferrite respectively. After quenching and tempering, the matrix microstructure was tempered sorbite, and a little of tempered martensite with undissolved carbides. The size of carbides decreased obviously which was about 200 nm. The carbide style transformed to orthorhombic M7C3and had the crystallographic orientation relationship of ([113])K//(200)α、[[512]]K//[[011]]α with ferrite. In addition, the [ΔH] and [ΔG] of formation and transformation of carbides were both below zero during this process.
		2014 Vol. 49 (9): 71-76 [Abstract] ( 1369 ) [HTML 0KB] [PDF 0KB] ( 78 )

	77	SUN Yong-qing, LIANG Jian-xiong, YANG Zhi-yong, LIU Zhen-bao, LI Wen-hui, ZHANG Li-na
		Effect and Mechanism of Heat Treatment on Mechanical Property of AM355 Steel
		Different heat treatment process on AM355 steel bars were searched, which were produced by VIM+ESR technique and forged into φ80mm. Mechanical properties were tested after different quench temperatures, followed by same deep cold and different temperature. The results show that, with a contrast of traditional heat treatment （1 070 ℃×1 h AC＋（－70 ℃）×8 h＋200 ℃×2 h AC）, new heat treatment process (1 000 ℃×1 h AC＋（－70 ℃）×8 h＋450 ℃×2 h AC＋200 ℃×2 h AC) can lead a rise of about 100 MPa in strength and 5HRC in hardness. Details of mechanical property are: [Rm＝]1 630 MPa, [Re＝]1 380 MPa, [A＝]16%, [Z＝]59%, impact energy 51 J, 50HRC. Sorts and precipitations of carbides in this AM355 bar were carried out by SEM and TEM, and strengthening mechanism were also searched. In conclusion, the quenching temperature has main effect on grain size, carbides, remained austenite, etc., and the exist of M23C6 carbide can lead a high strength.
		2014 Vol. 49 (9): 77-80 [Abstract] ( 1329 ) [HTML 0KB] [PDF 0KB] ( 54 )

	81	SUN Lei-lei, BAI Ming-zhuo, ZHENG Lei
		Influences of Two-Stage Cooling Processes on Microstructure of Strain-Based Designed X70 Pipeline Steel
		Steel with ferrite-bainite dual phase has been extensively researched for the strain-based designed pipeline applications owing to the high deformation resistance through successively yielding of the two phases. In order to explore the relationships of processes and dual-phase microstructure, the influences of two-stage controlled cooling processes on the microstructure transformation of deformed austenite in strain-based designed X70 pipeline steel are investigated through compression experiments conducted by Gleeble-3800. The results indicates that holding temperature for a short time after slow cooling stage could effectively promote ferrite precipitation, thereby refine ferrite grain. In addition, with the accelerated cooling start temperature lowering, the ferrite fraction increased. During the accelerated cooling stage, either increasing the cooling rate or lowering the cooling finish temperature could decrease the lath width and the sizes of carbides in the bainite structure and then improve the microhardness.
		2014 Vol. 49 (9): 81-86 [Abstract] ( 1211 ) [HTML 0KB] [PDF 0KB] ( 50 )

	87	CHENG Jian-hua, SHEN Jun-chang, HE Yi-zhu, SU Hang, CUI Li-hui
		Effect of Quenching, Lamellarizing and Tempering Process on Strength and Toughness of 9NiCrMo Steel
		The mechanical properties of 9NiCrMo steel subjected to quenching and tempering (QT) and quenching, lamellarizing and tempering (QLT) heat treatments was investigated, and the microstructure was systematically studied by means of optical microscope(OM) and scanning electron microscope (SEM). Moreover, quantity and distribution of reversed austenite in 9NiCrMo steel after QLT heat treatment was studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Based on the experimental results, the effect and mechanism of QLT heat treatment on mechanical properties of 9NiCrMo steel were analyzed. The results indicate that QLT heat treatment can improve the cryogenic toughness of 9NiCrMo steel effectively without reducing the strength. And dual phase structure and the changed distribution of the reversed austenite after QLT heat treatment are the main reasons which improve the cryogenic toughness.
		2014 Vol. 49 (9): 87-91 [Abstract] ( 1680 ) [HTML 0KB] [PDF 0KB] ( 69 )

	92	HE Xuan-ming, FU Peng-rui, WANG Chun-xia, LIN Hong-tao, WU Shuo, CAO Shi-xin
		Combustion Behavior of Low Rank Coal Char Application in Blast Furnace Injection
		Using fixed bed pyrolysis apparatus preparation of co-pyrolysis coal char of Shenmu long-flame coal and water hyacinth and metallurgical industry wastes at final pyrolysis temperature of 450 and 550 ℃ respectively. Reaction of pulverized coal injection (PCI) in a blast furnace was simulated using a drop tube furnace (DTF) to investigate the burnout behavior of a number of co-pyrolysis coal char and the influence of final pyrolysis temperature and co-pyrolysis material on combustion behavior. The result shows that blast sludge and cold rolling iron oxide could catalytic coal pyrolysis, and blast sludge had the optimal catalytic effect, and the growth of volatile is 18.4%; the optimal burnout of co-pyrolysis coal char was coal and cold rolling iron oxide pyrolysis at final temperature 550 ℃; the burnout degrees increased by 22.5% compared with raw coal char which was prepared at the same final pyrolysis temperature; SEM results show that the coal co-pyrolysis with cold rolling iron oxide produced more crack on char surface; in addition to co-pyrolysis coal char of coal and iron slag of steel rolling and blast sludge, the various performance of co-pyrolysis coal char in this experiment were consistent with the Chinese injection coal indexes.
		2014 Vol. 49 (9): 92-97 [Abstract] ( 1428 ) [HTML 0KB] [PDF 0KB] ( 59 )

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