IRON AND STEEL

钢铁

Home | About Journal | Editorial Board | Instruction for Authors | Subscriptions | Advertisement | Contacts Us | Chinese

　

Office Online

　

　

　

　

　

　

Editor-in-chief

　

Journal Online

　

　

Forthcoming Articles

　

　

　

　

Download Articles

　

　

Quick Search

Advanced Search

	2014 Vol. 49 No. 8
	Published: 2014-08-15

	1	CANG Da-qiang, , WEI Ru-fei, , ZHANG Ling-ling, BAI Yuan-yuan
		Formation Mechanism and Emission Reduction of PCDD/Fs in Iron Ore Sintering
		Iron ore sintering is an important industrial source of dioxin (PCDD/Fs), and the mechanism of generating dioxins in sintering process is very complex. Reaction by a precursor compound of an organic compound and De novo are two main ways, and De novo is the main way. Dioxins in the sintering machine are produced not only in the dry zone, but also produced in exhaust flue after the sinter zone and the combustion zone. There are three ways to reduce emissions of dioxins: source control, process control and operation, and treatment in the end. Source control is the best choice for the inhibition of dioxin, and treatment in the end is often chosen in the current process. Single dioxin abatement technologies may not be feasible for the complexity of sintering flue gas composition, and the investment is relatively large. For the technical characteristics of the sintering process and flue gas, the best way is synergistic emission reduction. Circulating sintering flue gas can reduce dioxins, [NOx] and dust content, etc. So it will be an important development direction.
		2014 Vol. 49 (8): 1-8 [Abstract] ( 1834 ) [HTML 0KB] [PDF 0KB] ( 43 )

	9	CHENG Xiang-ming, BI Xue-gong, SHI Shi-zhuang, MA Yi-rui,LI Peng, ZHANG Hui-xuan
		Effect of Ferro-Coke and Iron Ores Mixing Charging on Primary Slag Formation in Blast Furnace
		The profile and position of the cohesive zone is one of the key factors affecting the blast furnace stable operation. The effect of ferro-coke mixing into the burden materials on primary slag formation process in the blast furnace was experimentally studied. Seven kinds of iron-bearing burden were studied. The results demonstrated that the addition of ferro-coke can lower the compression starting temperature of all samples. This is because ferro-coke starts to react with CO2 at lower temperatures and increases the difference between the CO concentration in gas and the equilibrium content, accelerating the indirect reduction of iron ore. Moreover, the addition of ferro-coke would generally increase the softening-end temperature and decrease the melt-down temperature, leading to smaller softening-melting temperature range by a large margin. This suggests the mixing of ferro-coke into iron ores can remarkably improve the permeability of blast furnace stock. The addition of ferro-coke increased significantly the carbon content in dropped liquid iron. Giving priority to the effect on the stock permeability, it was suggested to use the ferro-coke prepared with 20% iron ore A.
		2014 Vol. 49 (8): 9-14 [Abstract] ( 1363 ) [HTML 0KB] [PDF 0KB] ( 74 )

	15	DING Shan， XUE Qing-guo， SHE Xue-feng， WANG Guang， NING Xiao-yu， WANG Jing-song
		Effect of CaCO3 on Direct Reduction-Smelting Separation of Vanadium-Bearing Titanomagnetite Concentrate
		Vanadium-bearing titanomagnetite concentrate was direct-reduced and smelt-separated isothermally with graphite and CaCO3. The influences of alkalinity and cooling technique on reduction and smelting separation were studied. XRD and chemical analysis were used to characterize the reduced samples. Results shows that the increase of alkalinity is beneficial to the reduction and smelting separation of vanadium-bearing titanomagnetite concentrate in the context of low alkalinity[(R=0-0.7)]. Metallized pellets smelt-separated well at the temperature of 1 600℃ after melting 20 minutes with the alkalinity of 0.5, the slag dosen’t include iron nearly. Air-cooling technique is beneficial to increasing anosovite content of slag, but not to separating out of magnesica-alumina spinel. Furnace-cooling technique is beneficial to separating out of magnesica-alumina spinel, but not to increasing anosovite content of slag.
		2014 Vol. 49 (8): 15-20 [Abstract] ( 1391 ) [HTML 0KB] [PDF 0KB] ( 55 )

	21	YIN Xue， SUN Sai-yang， SUN Yan-hui， ZHAO Yong， GE Liang， ZHANG Xi-chao
		Inclusion Behavior of LCAK Steel in Tundish Pouring Process
		The variations of inclusion characteristic of LCAK in tundish and normal slabs produced by BOF-Ar station-CC processes were studied by systematically sampling in different pouring time and nomal slabs of steel production. Analysis methods mainly include total oxygen and nitrogen content analysis, optical microscopy, scanning electronic microscope (SEM), and energy dispersive X-ray spectroscopy (EDS). The results show that: Total oxygen content at the starting and end of ladle pouring is higher than the middle pouring, which indicate that there exists re-oxidation during ladle change practice. The inclusions in tundish and normal slabs are classified into three types according to their morphology and composition: alumina inclusions; MnS inclusions; tundish flux inclusions or ladle slag inclusions. Inclusions of tundish and slab mainly contain Al2O3 inclusions with the size of 1-4 μm,also there are lots of MnS inclusions in the slab result in the rising of the number density. The number of bubble+alumina inclusions increases on steel of higher sulphur content. To sum up, at the stage of starting and end of pouring after the exchange of ladle, re-oxidation is the main reason which restrain the quality of the slab.Meanwhile, the sulfur content in steel should be controlled in a certain range in order to decrease the bubble+alumina inclusions and also avoid the precipitation of MnS inclusions during the solidification process.
		2014 Vol. 49 (8): 21-26 [Abstract] ( 1476 ) [HTML 0KB] [PDF 0KB] ( 56 )

	27	MA Deng, GUO Pei-min, PANG Jian-ming, ZHAO Pei
		Theoretical Analysis and Industrial Experiment of Direct Alloying of Molybdenum Oxide for 316L Steel
		A new smelting method was raised that molybdenum trioxide instead of ferromoly, was added to AOD furnace for 316L stainless steel. Based on the new method, thermodynamics of reduction of molybdenum trioxide was analyzed by the main elements in the AOD bath，the reduction mechanism of MoO3 was discussed and the formula of its reduction rate was deduced. In addition, it was involved that how the moly-oxide was put into the AOD furnace. There was a brief account of industrial practice in which moly-oxide was used for the refining of 316L stainless in AOD furnace. It shows that on one hand, the moly-oxide AOD furnace possesses excellent condition for the reduction of moly-oxide, for which reason it will be completely reduced in half an hour, on the other hand, it is better to utilize moly-oxide composite pellet containing moly-oxide, reductant and inhibitor for steady and safe refining process and the best use of moly- resource.
		2014 Vol. 49 (8): 27-30 [Abstract] ( 1202 ) [HTML 0KB] [PDF 0KB] ( 67 )

	31	WANG Xin-chao, YOU Zhi-min, CHENG Guo-guang, KOU Yu-shan, ZUO Hui, CHEN Lie
		20Cr13 Stainless Steel Smelted by VOD Furnace Under Silicon Deoxidation Process
		Under the background 20Cr13 stainless steel smelted by 30 t EAF-VOD-LF-IC process, through thermodynamic calculation, effects of basicity, alloy content and steel temperature under the process of re-slag on the equilibrium oxygen content of liquid steel were studied after silicon deoxidation treatment in VOD refining process. The results show that the oxygen content is significantly decreased with the basicity of the slag increasing, the slag basicity should be in more than 2 in actual production. In order to ensure the smelting effect of adding alloy for deoxidation of liquid steel, It should ensure that the silicon content of 0.3% or more. With the temperature decrease, the equilibrium oxygen content in steel will decrease. Effects of slag basicity on the content of dissolved equilibrium oxygen content and the total oxygen content of actual production is basically in the same. A linear relationship between the content of dissolved equilibrium oxygen content and the total oxygen content of actual production was fitted.
		2014 Vol. 49 (8): 31-34 [Abstract] ( 1435 ) [HTML 0KB] [PDF 0KB] ( 68 )

	35	LIU Yan,, CAO Jian-ning， GENG Ming-shan,, LI Yao-jun,, ZHAI Xiao-feng, ZHAO Chang-chun
		Technology for Large Rectangular Ingot Production With Intensive Water Cooling
		Large ingots are mainly used for production of supper thickness plates . With the increasing of ingot mass, the porosity is so deep on the upper of ingot that the metal yield is reduced, and the organization density is relatively poor and segregation is serious. So the large-rectangular ingot quality becomes the bottleneck to play heavy plate mill capacity. Aim at the problem , the equipment for casting large ingot with intensive water cooling was used to produce a kind of large rectangular ingot with 60 t successfully. The ingot was rolled into 220 mm thick steel plate. Although the composition is in the range of Q345B, the performance indexes met the stand of super thickness Q345E-Z35 plate, and the yield strength was 348 to 373 MPa, the tensile strength was 562 MPa to 588 MPa, percentage elongation was 17% to 28.5%, the transverse impact energy was 56.57 to 71.65 J and the longitudinal impact energy was 40.76 to 88.80 J at －40 ℃, the average percentage reduction in area was 63.04% at 1/2 thickness and 57.93% at 1/4 thickness .The total inclusions grade was not exceed 2.0, the grain fineness was 8 to 9. The result shows that the technology for production large rectangular ingot with intensive water cooling can provide the stocks for super thickness plates.
		2014 Vol. 49 (8): 35-41 [Abstract] ( 1215 ) [HTML 0KB] [PDF 0KB] ( 43 )

	42	ZHANG Xing-zhong, LIU Qing-guo, HUANG Wen, FANG Yi-ming
		Investigation of Non-Sinusoidal Oscillation Waveform Function and Technological Parameters for Continuous Casting Mold
		At the time of preventing the steel leaking, the non-sinusoidal Oscillation techniques can shorten the negative strip time and enhance the slab surface quality during steel continuous casting. But Non-sinusoidal vibration’s acceleration is higher than sine vibration, and it is easy to impact thus reduce the mold movement stability. To solve this problem, a new type of waveform function of the mold non-sinusoidal oscillation is constructed, in which the acceleration can be adjusted to the realistic situation to ensure the dynamic characteristics of the waveform function. For this waveform function, in the case of constant acceleration, the enlargement of the waveform deviation factor results in the shortness of negative strip time. The character of non-sinusoidal oscillation can be enlarged without affecting the movement smoothness of mold. Moreover, in the case of the constant waveform deviation factor, the shorter negative strip time makes the acceleration smaller. So at the time of enlarging the mold movement smoothness, the slab surface quality can be enhanced. By analyzing the parameters of oscillation technology, the calculation method of each oscillation technological parameter is presented, the multi-technological-parameter curves are given and provides reference for establishing the control model of casting speed and oscillation frequency.
		2014 Vol. 49 (8): 42-47 [Abstract] ( 1363 ) [HTML 0KB] [PDF 0KB] ( 55 )

	48	ZHU Shi-li,, ZHENG Guo-qu, YE Jian-song, HU Wen-hao, CAO Hua-zhen
		Influence of Spraying Intensity on Solidification Structure of Continuous Casting Billet During Secondary Cooling
		The relationship between spraying intensity and casting parameters was derived during secondary cooling of continuous casting, and the solidification structures of billets with two different sections were compared under different spraying intensities. The results showed that it was more accurate to express the relationship between solidification structures of billet and cooling parameters by using spraying intensity. Dendrite arm spacing was about 20 μm in the surface of billets and about 200-350 μm in the centre. The dendrites in diagonal area were tinier than those in lateral area at the same distance from surface of billet. Under the similar spraying intensity, the rules of solidification for billets showed that the structures in centre area were tiny for billets with cross-section of 200 mm×200 mm, but tiny structures existed in areas close to centre for billets with cross-section of 150 mm×150 mm. During solidification of billets, the left curve of solidification laws was obeyed basically from surface to center, but it was the right curve for centre area and areas close to centre when the cross-sections of billets were larger than 200 mm×200 mm.
		2014 Vol. 49 (8): 48-53 [Abstract] ( 1274 ) [HTML 0KB] [PDF 0KB] ( 34 )

	54	LIU Zhi-liang, ZHANG Li-pu, LIU Cai-yi, WANG Ying-jie
		Analysis of Flattening Amount of Two-Roller Straightener for Small Section Tubes
		Flattening and reverse bending straightening is an effective way to improve the straightening precision of small cross section tube. As the flattening amount was not easy to determine during tube straightening process, a three-dimensional finite element model of two-roller straightening process of tubes was established using finite element software. The variations of contact length, residual stress, straightening force, straightness and ovality under different flattening amount have been studied. It has been found that the reasonable value range of flattening amount is 0.4－0.7 mm. Using the value range to adjust the roll gap can get a good straightening effect in the field experimentation, and reduces the time of adjusting the roll gap.
		2014 Vol. 49 (8): 54-58 [Abstract] ( 1468 ) [HTML 0KB] [PDF 0KB] ( 84 )

	59	WANG Hai-yu, YANG Quan, WANG Xiao-chen, CHEN Yu-feng, DONG Li-jie, ZHANG Xi-bang
		Analysis and Control of Effect of Slab Deviation on Camber in Rough Rolling
		For the problem of slab camber in rough rolling of a conventional hot rolling, the static coupling model of roll and slab was firstly established by using ABAQUS/Standard and the quantitative effect of entry slab deviation factor of the different entry thickness, width, reduction, temperature difference on both sides and initial work roll contour on existing slab wedge was calculated. Meanwhile, the work roll contour after the static model was obtained. Then, in the same conditions of entry slab deviation factor, the dynamic simulation model established by ABAQUS/Explicit simulated the phenomenon of slab camber, which adopted the work roll contour of static model calculation, and further calculated quantitatively effect of entry slab deviation factor of the different entry thickness, width, reduction, temperature difference on both sides and initial work roll contour on exit slab camber. Based on the above calculation results, the opening gap margin of side guide and initial work roll contour of rough rolling was optimized to enhance the alignment during the course of rolling. The centerline deviation values which do not meet the standard rate declined from 6.51% to 2.93%, and the wedge hit rate of products was improved to 89% through using the above method. Thus, the above method to improve the phenomenon of slab camber achieved remarkable results and greatly improved the quality of products.
		2014 Vol. 49 (8): 59-63 [Abstract] ( 1389 ) [HTML 0KB] [PDF 0KB] ( 63 )

	64	SUN Jing-na,, XUE Tao,, DU Feng-shan,, LIU Rui-fen,
		Strip Shape and Gauge Integrated Set Model of UCM Cold Mill?Based on Rigidity Characteristics Analysis
		The three-dimensional dynamic UCM mill model is established by nonlinear elastic-plastic finite element method. The horizontal and vertical stiffness of the rolling force, the work roll bending force, the work roll bending force are calculated systematically by the model. The effects of the intermediate roll shift on the horizontal and vertical rigidity of rolling force are calculated by the model. Based on the mill rigidity analysis the paper presented the setting models of intermediate roll shift, roll bending force and roll gap and established the integrated set strategy of shape and gauge for UCM cold mill. The set strategy of strip shape and gauge integrated is verified by the finite element model and the gauge and shape meet the requirements after set.
		2014 Vol. 49 (8): 64-69 [Abstract] ( 1297 ) [HTML 0KB] [PDF 0KB] ( 54 )

	70	ZHANG Xiu-li, CHEN Ming-xin, LIU Zhen-bao, LIANG Jian-xiong, YANG Zhi-yong, YU Qiang
		Effect of Heat Treatment on Mechanical Properties and Corrosion Resistance of 15-5PH Stainless Steel
		This paper studies the effect of heat treatment on mechanical properties and corrosion resistance of 15-5PH precipitation hardening stainless steel, and observes the precipitated phase in steel.The results show that the strength of steel decreased with the aging temperature increased and the aging time extended, while the toughness of steel increased. This is caused by the reverse austenite volume fraction increased with the temperature raised; The pitting corrosion resistance of the steel reduced along with the aging temperature increased, the corrosion resistance of steel was at the poorest when aging at 580 and 600 ℃, while the corrosion resistance of steel reached the best and the strength was the highest when aging at 480 ℃, and the main precipitated phase was a rich copper phase of face-centered cubic structure in steel.
		2014 Vol. 49 (8): 70-75 [Abstract] ( 1423 ) [HTML 0KB] [PDF 0KB] ( 67 )

	76	QI Liang，, WANG Zhi-gang, HE Ling-hui
		Strain Aging Behavior of X100 Pipeline Steel as Hot Continuous Rolling
		The impact of strain and aging temperature on microstructure and mechanical properties of X100 pipeline steel as hot continuous rolling and its internal friction during aging were investigated by means of SEM, TEM, EBSD and virban inverted torsion pendulum-internal meter. The results show that only massive ferrite deforms remarkably when stain is less than 3%, and granular bainite shows a significant deformation when stain is more than 3%. With the increase of strain, the dislocation density increases and many substructures are formed in Ferrite laths, while the amount of high angle grain boundaries and toughness decrease significantly. With the increase of aging temperature, both tensile strength and yield strength show a rising trend, and the impact of strain on strength is greater than impact of the aging temperature. The test of internal friction conforms that the aging strengthening of X100 pipeline steel is mainly attributable to the pinning effect of carbon atom in free state on the dislocation density.
		2014 Vol. 49 (8): 76-80 [Abstract] ( 1408 ) [HTML 0KB] [PDF 0KB] ( 40 )

	81	KONG Yu-ting, ZHANG Chun-ling, YANG Jin-feng, SHAN Mei
		Microstructure Evolution of Cu-P-Cr-Ni-Mo Weathering Steel by Multi-Pass Rolling Simulating in the Intercritical Region
		The microstructure refinement supplies an alternative approach to improve the strength of low carbon steel without loss of room temperature ductility. The microstructure evolution of weathering steel Cu-P-Cr-Ni-Mo in multi-pass hot deformation in the intercritical region was investigated by means of hot compression simulation. The results indicated that the fine ferrite grains of 1.8 μm can be achieved under the conditions of general large strain through multi-pass deformation in the intercritical region. The banded second phase distributed on the ferrite matrix and turned thinner with the passes increasing. Microstructural analysis shown that at the forehead passes deformation, the strain was large enough to lead strain enhanced ferrite transformation and promoted large number of ferrite nucleation, precipitation and refinement. While the continuously dynamic recrystallization of ferrite was responsible for the ferrite grains refinement at the latter passes deformation. A lot of subgrains appeared and the misorientation angle between subgtrains continuous increasing led to forming high angle grain boundaries (HAGBs) and the coarse grains were segmentated.
		2014 Vol. 49 (8): 81-87 [Abstract] ( 1237 ) [HTML 0KB] [PDF 0KB] ( 70 )

	88	LIU Qing-suo, YANG Wei-wei, YUAN Lian-jie, GAO Bin, MENG Liang
		Effect of High Temperature Relaxation?Process on Ultra Low Carbon Bainite Steel Without Nb, Ti and Other Elements
		For the experimental steel the middle temperature phase transition point features of the high temperature relaxation?process of the experimental steel, the isothermal phase composition under the 450 ℃, the state of microstructure, and the hardness when the isothermal time changes were studied. In order to get the new knowledge of the effect of high temperature relaxation?process to the ultra low carbon steel without Nb, Ti alloy compounds precipitate elements’ bainite transition. The results show that high temperature relaxation?process significantly affected the experimental steel’s medium temperature transformation point. Although the CCT curve had two section characteristic, it moved to the left above compared with the samples which did not go through high temperature relaxation?process. The dislocation cell structure forming in the high temperature relaxation?process led to the forming of lath bunchy bainite with smaller size under 450 ℃ short-term isothermal, and the steel have a higher level of hardness. With the extension of isothermal time, the bainite grew up, and the hardness declined. While the samples without high temperature relaxation?process went through deformation-recovery process and bainite transformation process under the same 450 ℃. These two processes both had an effect on the steel’s hardness by working together to make the hardness change slowly when the isothermal time was less than 30 min.
		2014 Vol. 49 (8): 88-93 [Abstract] ( 1258 ) [HTML 0KB] [PDF 0KB] ( 71 )

	94	WU Nian-chun, CUI Qiang, FAN Yi, LI Heng-kun, LI Xiang
		Effect of Controlled Cooling Rate on Microstructure and Mechanical Properties of a High Perfomance Steel for Bridge
		In order to get a lower yield ratio and higher toughness of the high performance bridge steel Q500qE, relationship between microstructure and mechanical properties of the test steel varied with cooling rate was investigated with the Gleeble-3800 simulator. The results indicated that the microstructure of the test steel is primarily acicular ferrite (AF) and granular bainite ferrite (GBF) in all cooling rate, dispersed with M-A constituent under 5-25 ℃/s. Grain size of ferrite and maximum chord of M-A constituents decreased with the increasing of cooling rate, while the strength and yield ratio increased. The proper range of cooling rate for 500 MPa graded high performance bridge steel has been confirmed as 15-20 ℃/s.
		2014 Vol. 49 (8): 94-99 [Abstract] ( 1356 ) [HTML 0KB] [PDF 0KB] ( 74 )

钢铁

　

News

　

　

·

·

·

·

·

　　　　　　　　　　More

　

Author Center

　

　

Instruction for Authors

　

　

Copyright Agreement

　

Links

　

·	Links

　　　　　　　　　　More

Copyright © IRON AND STEEL　
Supported by: Beijing Magtech