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	2015 Vol. 50 No. 2
	Published: 2015-02-15

	1	ZUO Hai-bin，WANG Cong，ZHANG Jian-liang，ZHAO Yong-an，JIAO Ke-xin
		Application status and important technical indexes of BF hearth refractory
		Based on BF long campaign concept， the importance of high quality refractory materials for BF hearth was discussed; BF hearth refractory materials can be divided into three categories as follows: the carbon brick， the corundum brick and the carbon composite brick. The development of these three kinds of refractory materials at home and abroad was described. The mechanism of four important performance indicators was explained， including the thermal conductivity， hot metal corrosion index， slag resistance and micro porosity index. The performance indexes of the three kinds of refractory were compared. The results are as follows: the comprehensive performance of carbon composite brick is better than that of carbon brick and ceramic cup；the development of refractories should pay attention to improve the index co-ordination；the carbon composite material is the development direction of the new generation of hearth lining.
		2015 Vol. 50 (2): 1-6 [Abstract] ( 1308 ) [HTML 0KB] [PDF 0KB] ( 77 )

	7	YANG You-hui，ZHU Zi-zong，XIONG Hao，JI Huan-lin，WANG Xin-hai，SHENG Jian-wen
		Modification of non-coking coal for coking application of coal petrography theory
		Through the analysis of the coal and rock properties of coking coal， and testing the coke crushing strength in the 40 kg coke oven， the study identified the reactive weight function based on the coking coal vitrinite maximum reflectivity. The reactive-inert component radio of coking coal base on the active weight function was calculated， and it is concluded that the reactive-inert component radio correspond to the maximum crushing strength of coke. As the result of experiment analysis and calculation， the value of best reactive-inert component radio is 2.53. Aiming to reach the best reactive-inert component radio， the study optimized the ratio of mixing coal， predicted the coke quality， and provided technical basis to determine coal blending ratio conveniently. At the same time， modification of non-coking coal makes the non- coking coal contain certain activity， and the optimal proposal of coal blending of non-coking coal can add up to 10% at least， be helpful to get qualified coke.
		2015 Vol. 50 (2): 7-11 [Abstract] ( 1267 ) [HTML 0KB] [PDF 0KB] ( 70 )

	12	YAO Jun-hao，，YANG Jun，HAN Dong，GUO Xing-min，
		Effect of additives on formation of calcium ferrites in magnesia-riched sinters
		Production of rich-containing MgO sinters has become one of the effective ways to solve the problems，such as high viscosity and low desulfurization ability of the slag which was brought by large use of high-alumina iron ores in blast furnace. However，rich-containing MgO raw materials decrease the quantity of binding phase during sintering process to make the strength of sinter worse. This study aims to increase the amount of calcium ferrite(SFCA) by adding additives with low melting point into iron ore fines to improve the quality of sinters. The B2O3，CaCl2 and Na2SiO3 were used as additives to add into high-alumina iron ore fines with rich-containing MgO. The effect of additives on sintering process was investigated according to the results of patterns and optical microstructure of sintered samples from XRD. The results showed that the three kinds of additives have a promotion to form SFCA，but the effects are different. When the mass percent of MgO is 4%，the appropriate amount（mass percent） of B2O3，CaCl2 or Na2SiO is 0.094%，0.470% and 0.470% respectively. It can promote SFCA formation with more amount，and little additive is good for acicular morphology. Another result indicates that increase of binding phase helps to generate more magnetite under the high content of MgO.
		2015 Vol. 50 (2): 12-16 [Abstract] ( 1460 ) [HTML 0KB] [PDF 0KB] ( 41 )

	17	ZHANG Ying-yi，，SHI Xue-feng，QI Yuan-hong，ZOU Zong-shu，GUO Yu-hua
		Slag composition mechanism based reduction and smelting of carbon composite bauxite pellets
		The smelting slag reaction mechanism was studied by thermodynamic analysis and coal-based direct reduction and smelting experiment. The experiment result shows that the slag basicity has an important influence on iron nuggets size， metal yield and slag composition. When the basicity were 1.00， 2.00 and 3.85， the iron nuggets yield were 91.55%， 44.53% and 88.48% respectively， the iron nuggets size were 15.50， 7.00 and 8.54mm respectively， and the smelting slag composition (mass percent) were 55%A-34%CA6-6%C2AS-4%Fe， 64%A-35%C2AS-2%Fe and 24%C2S-62%C12A7-7%C2AS-4%C3AS3-3%Fe respectively. When the slag basicity was 3.85， the reduction smelting slag is mainly composed of C2S and C12A7， which mass percent is about 85%. Only when the mixture is close to the slag line of C2S-C12A7 ([R]=3.85)， the C2S and C12A7 will appear in the cooling crystallization equilibrium phase.
		2015 Vol. 50 (2): 17-21 [Abstract] ( 1211 ) [HTML 0KB] [PDF 0KB] ( 80 )

	22	WU Wei，NI Bing，LIU Zhuang-zhuang，YANG Yong
		Theoretical and thermal simulation of titanium removal in combined blown converter
		The titanium removal in BOF converter process was simulated by experiment in 500 kg intermediate frequency induction furnace with top and bottom blowing function， and the reaction mechanism of titanium oxidation was investigated. The results showed that the average end point mass percent of Ti in hot metal was 0.008 2% and the rate of titanium removal was 71.3%. In summary， Ti removal rate is decreased with the increase of hot metal temperature， but increased with the increase of the of oxygen supply to the molten pool. There is a balance relationship between the end point Ti content and the end point Si content in hot metal as well as Ti and Mn. However， the end point Ti content is not associated with carbon oxidation. Ti distribution ratio between slag and hot metal ranges from 0.6 to 1.6， and it is increased with the increase of (FeO) content in slag， but decreased with the increase of hot metal temperature. The experimental result is consistent with the theoretical analysis which indicates that the reaction of titanium oxidation is more conducive to occur at lower temperature.
		2015 Vol. 50 (2): 22-26 [Abstract] ( 1255 ) [HTML 0KB] [PDF 0KB] ( 47 )

	27	LIU Cheng-song，LI Jing-she，GAO Xiao-jie，YANG Shu-feng
		Investigation on cleanliness of SPHC steel produced by BOF-LF-CC process
		Based on tracer production experiment， the cleanliness of SPHC steel produced by BOF-LF-CC process in a domestic steel plant was investigated by the way of sampling systematically and comprehensive analysis. The results showed that the mass of macro-inclusion after LF refining increased to 36.7 mg/(10 kg) compared with that after calcium treatment which was 19.6 mg/(10 kg). From the tapping of LF refining to tundish， the average mass percent total oxygen in molten steel increased from 23×10-6 to (36-48)×10-6 and existed a certain degree of re-oxidation. The results of tracer experiment revealed that serious entrapment of refining slag during LF refining and erosion of refractory in tundish occurred.
		2015 Vol. 50 (2): 27-31 [Abstract] ( 1863 ) [HTML 0KB] [PDF 0KB] ( 56 )

	32	DENG Xu-yan，， MA Jian-chao，ZHAO Wei-jie
		Castability improvement of high Ti-bearing welding wire steel
		Severe SEN (Submerged Entry Nozzle) clogging issue occurred in the continuous casting process of high Ti-bearing welding wire steel. The chemical composition of clogs was characterized using SEM/EDS. The results indicate that the major constituent phases are [TiOx] and solidified steel. The morphology and chemical composition of inclusions in liquid steel were analyzed by SEM/EDS. The results show the inclusion types at LF end are [MnO-Al2O3-SiO2-TiOx]， [MgO-Al2O3-TiOx] and [TiOx]. The Ti-bearing inclusions with high melting point in liquid steel are the dominant reason to SEN clogging. Al-Ti-O equilibrium in liquid steel and steel-slag equilibrium were calculated by thermodynamic method. The results show oxygen is preferred to combine with Ti to form Ti2O3 when [w([Al])/w([Ti])＜0.15]， otherwise， oxygen is preferred to combine with Al; the titanium would not be oxidized by slag when [w((FeO))][＜]0.05%， [w((SiO2))][＜]15% in ladle slag. TiOx inclusion content in liquid steel is reduced from 0.002 4% to below 0.001% after the process parameters and operation are optimized; hence， the castability of liquid steel is improved significantly.
		2015 Vol. 50 (2): 32-37 [Abstract] ( 1286 ) [HTML 0KB] [PDF 0KB] ( 68 )

	38	CAO Lei
		Surface longitudinal crack of slab and property of mold slag for continuous casting of peritectic steel
		A lot of longitudinal cracks were observed on the surface of 250 mm×1 820 mm wide heavy slab containing 0.120%-0.150% carbon， produced using the protecting slag for peritectic steel in one Wide Heavy Plate Plant. These surface longitudinal and subsurface cracks have been effectively controlled by improving the basicity of mold powder, decreasing mold powder viscosity and improving the heat transfer between the mold wall and the slab shell. The reason for the slab with 0.090%-0.120% carbon be free of surface cracks is the segregation crystallization, which causes the carbon content in the initial solidified shell is lower than 0.090%.
		2015 Vol. 50 (2): 38-42 [Abstract] ( 1377 ) [HTML 0KB] [PDF 0KB] ( 66 )

	43	BAI Zhen-hua，，LI Tao，，CUI Ya-ya，，GUO Qian-yong，，LIU Ya-xing，，LI Xiu-jun
		Control technology of complex wave for 4-high temper mill
		In allusion to small reduction， less deformation and friction heat and small roll thermal crown of temper mill， multi-zone cooling is incapable of controlling complex wave defects such as center and double edge composite wave， single rib wave， multi rib wave， center and rib composite wave， edge and rib composite wave. Taking 4-high temper mill as research object， the study presented a set of asymmetrical structure to replace symmetrical structure， changed strip shape control method from traditional 2-dimensional symmetric roll bending(symmetric roll shifting) and roll tilting to 5-dimensional left roll bending， right roll bending， upper roll shifting， bottom roll shifting and roll tilting. On this foundation， the study built a set of suitable complex wave control technologies for 4-high temper mill in order to minimum the difference between actual strip shape and target strip shape. Through parameter optimization of strip shape control for left roll bending， right roll bending， upper roll shifting， bottom roll shifting and roll tilting， this control technology solved effectively the problems of control defect on 4-high temper mill complex wave and made up for the congenital lack of shape control on temper mill which is incapable of using fine control，which provides a set of new method for strip shape-fine control on field temper mill， with further popularization and application value.
		2015 Vol. 50 (2): 43-47 [Abstract] ( 1330 ) [HTML 0KB] [PDF 0KB] ( 58 )

	48	MA Yong-lin，GONG Mei-na， XING Shu-qing， LI Zhi-feng
		FEM analysis of 304 stainless steel strip flatness control
		In order to determine the effect of the intermediate roll shifting on the strip flatness， the dynamic software ANSYS/LS-DYNA was adopted to simulate intermediate roll control for rolling 304 stainless steel with different widths on twelve-high rolling mill. The loaded gap of work rolls and the strain distribution curve of the 304 stainless steel were calculated when the amount of intermediate roll shifting ranges from －30 mm to －50 mm. The results show that strip shape with good flatness can be obtained by dynamically adjusting the amount of intermediate roll shifting to make the value of length “[L]” to be 55%-60% of the initial width of strip.
		2015 Vol. 50 (2): 48-53 [Abstract] ( 1284 ) [HTML 0KB] [PDF 0KB] ( 54 )

	54	TIAN Zhong-liang， BAO Han-sheng， HE Xi-kou， LIU Zheng-dong
		Research development on the heat resistant alloy used for 700 ℃ USC turbine rotor
		The high pressure and intermediate pressure turbine rotor are the core components of 700 ℃ USC power plants. Many researchers are focusing on the candidates material used for HP and IP rotor. New developed ferritic and austenitic heat resistant steels promotes the construction of 600 ℃ USC power plants. But ferritic and austenitic steels can’t be used for high temperature components of 700 ℃ USC plants， and nickel based alloy must be considered. The technological characteristics of heat resistant alloy used for 700 ℃ USC steam turbine rotor were introduced. The latest research results on material selection and commercial manufacture in Europe， America and Japan was reviewed. Moreover， the development of heat resistant alloy for 700 ℃ USC turbine rotor in China was discussed.
		2015 Vol. 50 (2): 54-60 [Abstract] ( 1380 ) [HTML 0KB] [PDF 0KB] ( 61 )

	61	WANG Ge,WANG Li-li,GAO Jing-na,ZHU Guo-shan,DU Xiong-fei,LI Qiang,
		Numerical simulation on quenching process of the large-diameter thick-wall gas cylinder of 30CrMo steel
		A three dimensional coupling model on temperature, microstructure and stress of the 30CrMo large-diameter and thick-wall gas cylinder during quenching process was built with use of finite element numerical simulation technology. Temperature distribution, phase transition and stresses variation of the gas cylinder during quenching processes were investigated. Two quenching processes are compared, i.e. quenching immersed in a water groove and quenching intermittent sprayed inside with continuous water sprayed outside on the cylinder respectively. Numerical simulation results show that the temperature difference between the internal surface and the outside surface of the cylinder was very large and a higher peak value of quenching heat stress emerged during quenching immersed in the water groove, which would lead to a large deformation of the gas cylinder and the shell could not be through hardened completely. The cooling intensity was reasonable under the quenching process by intermittent sprayed inside with continuous water sprayed outside on the gas cylinder. The temperature gradient and the quenching stress were reduced, the quenching distortion was eliminated, the microstructure distribution was improved and the uniformity of microstructure and hardness of the gas would be realized during this quenching process.
		2015 Vol. 50 (2): 61-69 [Abstract] ( 1385 ) [HTML 0KB] [PDF 0KB] ( 70 )

	70	JIANG Wen， ZHAO Kun-yu， YE Dong， LI Jun， SU Jie， YONG Qi-long
		Effect of heat treatment technology on reversed austenite in super martensitic stainless steel
		Beijing 100081， China) The effect of adding different content of Cr to the super martensitic stainless steel (SMSS) on formation of reversed austenite subjected to quenching and tempering by using optical microscope(OM)， X-ray diffraction (XRD)， transmission electron microscope (TEM) and energy dispersive spectrometer(EDS) was studied. The experimental results indicate that the microstructures of two tested steels were tempered martensite and reversed austenite after tempering. The volume fraction and grain size of reversed austenite in two tested steels increased first and then decreased with the increase of tempering temperature， which reached the maximum at 650-700 ℃. When the reversed austenite re-dissolved and transformed to martensite， there was an effect of refinement on the matrix. Compared with 13Cr steels， the reversed austenite in 15Cr steels was more and the size was bigger. The effect of refinement on the matrix was more obvious.
		2015 Vol. 50 (2): 70-75 [Abstract] ( 1420 ) [HTML 0KB] [PDF 0KB] ( 47 )

	76	YANG Wei-yu，DONG Rui-feng， GAO Feng，LI Zhi-li
		Effects of boron on hardenability and mechanical properties of 60 mm Q690D steel
		By jominy test， [Z] direction hardness test， microstructure and mechanical properties analysis，the effects of boron on hardenability and mechanical properties of 60 mm Q690D steel were studied. The results show that the trace solution boron can significantly improve the hardenability of 60 mm Q690D steel; compared with the experimental steel without boron addition，quenching microstructure of experimental steel with boron addition was transformed from martensite/bainite complex phases to lath martensite at thickness of 1/4， the maximum hardness difference of [Z] direction at transverse section for quenching was reduced from 9HRC to 4HRC and that for tempering was reduced from 5HRC to 3HRC， which made the homogeneity of hardness at [Z] direction improved， as well as the strength and toughness for quenching and tempering of experimental steel with boron.
		2015 Vol. 50 (2): 76-80 [Abstract] ( 1522 ) [HTML 0KB] [PDF 0KB] ( 48 )

	81	CHEN Bo-yu， LIAO Lin-lin， WANG Ming-di， MENG Xiang， LI Hui， CHEN Yin-li
		Influence of cooling process on the phase transformation and microstructure of HRB400E
		The microstructure of HRB400E was decided by the cooling process after laying. The different cooling processes were simulated by Gleeble-3500 thermal simulation tester. The dilatometric curve and microstructure were analyzed under different cooling processes. The results indicate that the cooling rate and mutational temperature greatly influenced the final microstructure. The rational cooperation of these two parameters could dominate the fraction of bainite. With the increasing of cooling rate and decreasing of mutational temperature，the fraction of bainite enhanced.
		2015 Vol. 50 (2): 81-84 [Abstract] ( 1286 ) [HTML 0KB] [PDF 0KB] ( 49 )

	85	YAN Zhen-wu
		Application of oxy-fuel burning technology in reheating furnace of TISCO
		With rising energy prices and gradual increasing of environmental pressure， iron and steel enterprises need to adopt an efficient energy application method to mitigate the adverse situation currently facing. As an advanced oxyfuel combustion mode， the scale and scope of its applications are expanding. The technical advantages of oxyfuel technology in energy conservation and environmental protection were discussed， the status quo of a rolling mill furnace TISCO was analyzed and oxy-fuel feasibility and energy-saving effect and empirical analysis applications were analyzed.
		2015 Vol. 50 (2): 85-89 [Abstract] ( 1065 ) [HTML 0KB] [PDF 0KB] ( 61 )

	90	ZHENG Xu-tao，ZHANG Jie， LI Hong-bo， MA Heng-hao， ZHANG Peng-wu， HU Hai
		Effect of stiffness difference and its influence on strip contour asymmetry of hot strip mill
		Characters of strip contour on 2 250 mm production line were collected. The concept about contour asymmetrical character was proposed in a way that asymmetry was expressed by using the degree of asymmetry， which was integrated with linear term and cubic term wedge. This concept can be the base of evaluation and control of strip contour asymmetry. By measuring and analyzing the mill stretch curves under the contact roll condition， it is found that the stiffness differences between operation sides and work sides are obvious and can not be ignored. Roll deformation model of asymmetric rolling mill has been built by using the method of influence function. Through asymmetric rolling model and mathematic model， this paper analyzed the effects on contour asymmetry which was caused by stiffness differences. The strategies including the maintaining of key components and the preset adjustment of roll incline have been applied in industrial production and gained satisfying effort.
		2015 Vol. 50 (2): 90-95 [Abstract] ( 1315 ) [HTML 0KB] [PDF 0KB] ( 59 )

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