Simulation on solidification structure of 72A tire cord steel billet using CAFE method

The solidification microstructure has an important effect on the mechanical properties of castings. Therefore, an FE （Finite Element） - CA （Cellular Automaton） coupling model was developed for the simulation of solidification structure during the continuous casting process of 72A tire cord steel. In the model, the effect of phase transformation （λ→γ→α） during solidification was considered based on a thermodynamic database. The effect of electromagnetic stirring （EMS） was determined by increasing both the thermal conductivity and crystal formation rate in the liquid phase. The results show that the cooling curves and solidification structure calculated by this model agree well with the experimental results. The optimum pouring temperature range for tire cord steel casting was also discussed based on the present model. By comprehensive consideration of billet quality and smooth production, the pouring temperature should be controlled at about 1,495 ℃ under the casting conditions of the local plant in this study.

Forecast of steel cord demand after the financial crisis

To analyze the production and marketing of China automobile in Year 2009,and also the development of China automobile and steel cord in those 11 years.The single-element regression mathematics model was set up to analyze the steel cord demand and automobile production.It predicted that automobile production would up to 15 170 000,16 690 000 and 18 360 000 respectively from 2010 to 2012,with the confidence as of 95%,the steel cord consumption in those three years will be 1 180 000 - 1 370 000 t, 1 320 000 - 1 520 000 t and 1 470 000 - 1 680 000 t.As to the policy of China stimulation,The role of Chinese tire has converted from the export-oriented to domestic consumer smoothly,so the effect of US special protectionist tariffs is limited in China.

Progress of tyre cord steel in Baosteel

With the development of automobile industry,tire is marching toward lighter,energy-saving and safer,and it has been a trend for steel cord to develope in high strength and ultrahigh-strength.In order to reduce fracture of tire cord,steel cord is producted with bloom casting machine by soft reduction to reduce segregation,with clean steel smelt technology to control inclusion.TMCP of wire cord is improved in Baosteel.With technological advancement,the quality of steel cord has been noticeably raised and ultrahigh-strength has developed successfully.The paper introduces the development of steel cord in Baosteel.

Innovative Application of Scrap-Tire Steel Cords in Concrete Mixes

Many researchers have investigated the use of recycled tire products in several traditional civil engineering materials. This research is exploring the use of steel cords, a by-product of the tire recycling process, in concrete mixes. Different concrete specimens were fabricated and tested in uniaxial compression and splitting tensile strength. The steel cords were substituted into the concrete mix in volumetric percentages of various ratios. Results show that mechanical properties of concrete made with steel cords are improved compared with concrete mix made with the traditional scrap-tires recycled material. Also, results show that even though the compressive strength is reduced when using steel cords, this reduction is minimal. When 2% of steel cords are used there is 18% increase in ductility. Moreover, splitting tensile tests show that concrete mixtures with any steel cords content have much greater toughness than control mixture. This mechanical property mix indicates an excellent potential application of modified concrete mix in structures that absorb large amount of energy.

Effect of boron on inclusions morphology in tire cord steel

B_2O^3 was added into tire cord steel during refining in carbon tube furnace.The influence of boron which was added in tire cord steel on the deformability of oxide inclusions was studied by metallographic and scanning electron microscope(SEM) observation.The melting points of boron-bearing compound oxide inclusions were calculated by the software of Factsage.The results showed that the most part of inclusions were boron-bearing compound oxide and their deformation properties were obviously improved by adding B_2O_3 in steel.As the boron content was increased from 0.0046%to 0.039%,the proportion of long strip type inclusions changed a little and the number of inclusions decreased.The low-melting point areas of MnO-SiO_2-Al_2O_3 and CaO-SiO_2-Al_2O_3 ternary system were increased due to adding B_2O_3 in steel.Moreover,the areas increased with the increasing of B_2O_3 content in conclusions.Evident effect on low-melting point inclusion occurred when B_2O_3 content went up to 5% in CaO-SiO_2-Al_2O_3 inclusions system and to 10%in MnO-SiO_2-Al_2O_3 inclusions system.

Technical improvements of Baosteel EAF bloom caster production line

This paper presents the improvements on equipment and process technologies of Baosteel EAF Bloom Caster Production Line.By using the new VOD equipment,super low carbon super 13Cr was successfully made;By applying and developing the Soft Reduction technology,very good results were achieved on high quality steel grades such as tire cord steel,bear steel,hi-alloy steel;the ladle Anti-Slag Detector is normally applied,based on the detail analysis during the performance test period,the Detector gives out slag entrapment alarms 7-9 s average before slag flows into tundish.By optimizing production control points of each key process,great achievements are realized on high quality steel grades such as tire cord steel,bear steel,hi-alloy steel and hi-S/Al steel,etc.Some achievements and technical indices are presented,too.

Genetic Analysis for Large TiN Inclusions in Wire Rod for Tire Cord Steel of SWRH82A

The law of element segregation of Ti, N, Mn and S, and the sequence of selective precipitation of TiN and MnS inclusions during solidification of molten steel of SWRH82 A are studied on the basis of thermodynamics. The origin of large TiN inclusions which affect the titanium inclusions point penalty in SWRH82 A wire rod is analyzed based on the research on the distribution characteristics of MnS and large size of TiN inclusions observed on metallographic specimen of SWRH82 A steel wire rod. The solidification segregation ratio of Ti is far more than that of N, and the solidification segregation ratio of S is far more than that of Mn. In the range of cooling rate of the continuous casting production, the cooling rate of solidification has little effect on the segregation ratios of Ti, N, Mn and S. MnS inclusions will precipitate earlier than TiN inclusions during solidification of the molten steel of SWRH82 A. The large TiN inclusion which is wrapped by MnS in the SWRH82 A wire rod may be foreign inclusions and it is not precipitated product during solidification in the molten steel of SWRH82 A.

Effect of Boron on Morphology of Inclusions in Tire Cord Steel

B2O3 was added to tire cord steel during refining in a carbon tube furnace.The influence of boron on the deformability of oxide inclusions was studied by metallographic and scanning electron microscope（SEM） observations.The melting points of boron-bearing compound oxide inclusions were calculated using Factsage software.The results showed that the main inclusion was a boron-bearing compound oxide and the deformation properties of the inclusions were clearly improved by adding B2O3.As the boron content was increased from 0.0046% to 0.039%,the proportion of long strip type inclusions changed slightly and the number of inclusions decreased.The low-melting point areas of the MnO-SiO2-Al2O3 and CaO-SiO2-Al2O3 ternary system increased with the addition of B2O3.Moreover,the area increased with the increase of B2O3 content.Clear improvements in the deformation ability of the inclusions occurred when the B2O3 mass percent rose to 5% in the CaO-SiO2-Al2O3 inclusion system and to 10% in the MnO-SiO2-Al2O3 inclusion system

Precipitation and Solid Solution of Titanium Carbonitride Inclusions in Hypereutectoid Tire Cord Steel

The properties of titanium carbonitride Ti（CxN1-x） inclusions precipitated during solidification of tire cord steels and the thermodynamic conditions for their decomposition and solid solution during billet heating were investigated using a thermodynamics method. The solid solution of Ti（CxN1-x） inclusions during high-temperature heating was also studied experimentally. The results revealed that： （1） the higher the content of carbon in the tire cord steel is, the greater the value of .r in the Ti（CxN1-x） inclusions is; （2） the higher the content of carbon in the tire cord steel is, the earlier the Ti（CxN1-x） inclusions precipitated during the solidification process and the lower the solidification front temperature is during precipitation; （3） when an 82A steel sample was heated to 1087℃, the Ti（CxN1-x） inclusions possess the thermodynamic conditions of decomposition and solid solution; and （4） when 82A samples were heated to 1150 and 1 250℃, the total number of Ti（CxN1-x） inclusions larger than 5μm in diameter decreased by 55.0% and 70.3%, respectively. In addition, although smaller inclusions with diameter less than 2 μm continued to decompose when the sample was heated at 1 250℃ for 2 h and then cooled to 1000℃ in the furnace, the number of inclusions larger than 5 μm in diameter increased.

Prediction of maximum carbon element content in continuous casting billets of 82B cord steel based on statistics of extreme values method

The research of carbon content along the casting direction of 82B cord steel billets is of great significance for improvingthe quality of cord products from subsequent processing.However,the traditional segregation and billets quality evaluationmethods have certain limitations,such as sampling length and analysis area.which affect the accuracy of quality judgment.Thus.the statistics of extreme values(SEV)was introduced to predict the maximum value of carbon element contentalong the casting direction,which can quantitatively characterize the segregation degree.The size of the selected billet is150 mm×150 mm,and the sampling location is the centerline of the billet.The experiment was conducted by consideringthe effect of cooling intensity and casting speed on the maximum value of carbon element content.Firstly,the calculationresults show that the SEN method can predict the maximum value of carbon element content along the casting directionof 82B cord steel,and the SEV method is proved to be effective by analyzing the carbon distribution and fluctuation in billets.To some extent,the SEV method can break the limitations of the sampling length and analysis area by predicting themaximum value of carbon element on a larger range of continuous casting billets with few samples.During the continuouscasting process the increase in cooling intensity makes the surface shrinking rate increase,which can slow down the flowof solute-enriched liquid to the center,and the center segregation can be reduced.On the other hand,the function area ofthe final electromagnetic stirring can be expanded with the increase in the casting speed,which can reduce the concentration of carbon element in the center of the billets and reduce the maximum value of carbon element content.Ilt can providea new theoretical reference for the quantitative calculation of carbon content in continuous casting billets and the qualityevaluation of continuous casting billcts.

Effect of V and N on Microstructures and Properties of Grade-70 Tire Cord Steel during Cold Drawing

Commercial grade-70 tire cord steel was microalloyed with V and N to explore the possibility of substitu- ting V for C and the effect of V and N on cementite dissolution during cold drawing process. Tensile strength, elon- gation and torsion laps of cold-drawn wires were determined. Microstructures of secondary phases were studied by transmission electron microscopy （TEM） and energy dispersive spectroscopy （EDS）. Saturation magnetization was measured by using a vibrating sample magnetometer （VSM） to evaluate cementite dissolution during cold drawing process. Experimental results showed that with the increase of V content, tensile strength increased, elongation slightly decreased, and the torsion laps of the cold-drawn wires decreased. Results also showed that with the increase of N content, a peak （increasing first and then decreasing） appeared in the tensile strength graph, and an increase of elongation and a decrease of torsion laps of the cold-drawn wires occured. N is soluble in ferrite when its content is low. The increase in the content of N to 82 × 10^-6 will result in the precipitation of the V-containing secondary pha- ses. Also, cementite tended to be stable during cold drawing process with the increase of V and N contents. Grade-80 tire cord steel can be replaced by grade 70 tire cord steel microalloyed with 0. 086 mass% V.

耐冲击橡胶坝的研制

介绍耐冲击橡胶坝的结构设计、配方设计、生产工艺和产品性能。骨架材料上下两层选用钢丝绳网,中间两层选用锦纶66帆布。外层胶选用氯磺化聚乙烯(CSM)作主体材料,并加入石油树脂,提高抗冲击性能。堵头和坝体无缝搭接、硫化成型。坝袋下游一侧设计扰流板,以降低坝体振动、颤动。内外层涂刷相同颜色的CSM防护涂层,延长坝体使用寿命。该产品设计坝高6 m,使用寿命30年。

Thermodynamic Modeling of Deoxidation Products and Inclusion Chemistry in Mn/Si Killed Tire-Cord Steel

The present work deals with thermodynamic modeling of oxide systems, in the context of slags and inclusions in steelmaking. The work has emphasis on oxides encountered during the production of tire – cord steel. Control of inclusion chemistry and variation in eutectic temperature and eutectic composition of MnO-Al2O3-SiO2 slag system have been studied, using Thermo-CalcR software. Relatively low liquidus temperatures are obtained for ratio of MnO / SiO2 = 0.5 - 1.5 and Al2O3 content from 10 - 20 mass%. It has been observed that the addition of Alumina leads to further increase in the liquidus temperature. The stability of inclusions is analyzed in terms of free energy values of related slag systems; and an appropriate minimum of Gibbs free energy value of slag phase observed at around 50 ppm of Oxygen. The observations could not be verified using thermodynamic experiments, but have been compared with findings in the open literature.