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.

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.

Effect of Carbon Content on Ti Inclusion Precipitated in Tire Cord Steel

The precipitation of TiN inclusion during solidification of different carbon content of 0.72%, 0.82% and 0.95% in tire cord steel is thermodynamically studied respectively. The results show that the carbon content has obvious effect on TiN inclusion precipitated in tire cord steel of different strength levels. With the carbon content of tire cord steel increasing, the temperature before solidifying reduced gradually and the required activity product of titanium and nitrogen for TiN inclusion precipitation also declined gradually. With the same condition of initial Ti and N content in liquid steel, the size of TiN inclusion precipitated in tire cord steel of higher carbon content is bigger than that of lower carbon content. In order to control the harmful effects on processability of TiN inclusion precipitated in hypereutectoid tire cord steel of the ultra high strength level, the measures of smelting process must be taken to further reduce the titanium and nitrogen content in liquid steel.

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.

Research on the Solid Solution Behavior of Titanium Inclusion for the High Strength Tire Cord Steel

In order to improve the quality of the cord steel wire rod and achieve the effective control of titanium inclusion, the solid solution behavior of titanium inclusion in tire cord steel during the heating process was discussed in this paper, through the thermodynamic theory analysis, combined with the CLSM experiment. The conclusions are as follows: 1) According to the law of Ostwald repening, the coarsening rate of titanium carbonitride inclusion is very small, the coarsening behavior of titanium carbonitride inclusion cannot be considered in the heating and holding stage. 2) The solid solution behavior of titanium inclusion in the heating process is obviously existed. 3) Through the proper control of rolling temperature, holding time and the subsequent cooling rate, the size and quantity of large particle titanium inclusion in the high strength tire cord steel can be effectively controlled.

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.

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.

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.

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.

钢丝绳芯传送带损伤的漏磁检测

钢丝绳芯传送带是用于输送物料的高强度传送带,广泛应用于采矿、建筑、冶金等领域,其在长时间运行后,内部钢丝绳会出现断丝、磨损等缺陷,影响生产安全。基于漏磁检测技术开展了钢丝绳芯传送带的损伤检测,首先建立了含有不同类型和不同截面积损伤的传送带漏磁检测有限元模型,分析了缺陷漏磁场空间分布特性和变化规律,然后在实验室条件下开展传送带漏磁检测试验,采用滑动平均降噪与小波降噪相结合的方法对检测信号进行降噪处理,降噪后的信号能够清晰地显示出缺陷损伤严重程度。仿真和试验结果表明,漏磁检测技术能够检测出钢丝绳芯传送带中不同类型和不同截面积的损伤,能够为传送带使用和维护提供决策依据。

1×1钢丝帘线的开发与性能探讨

开发1×1钢丝帘线,并研究其性能。结果表明:采用校直器校直和加捻反扭两种工艺均可以得到符合设计要求的1×1钢丝帘线,校直器校直的钢丝帘线残余扭转更稳定,而加捻反扭的钢丝帘线直线性更好;在材料确定的情况下,1×1钢丝帘线的弯曲刚度和低负荷伸长率主要与直径相关,而与强度关系不大;在1500 MPa试验压力下,1×0.30ST钢丝帘线的亨特疲劳性能比2×0.30ST钢丝帘线更好。

全钢工程机械子午线轮胎胎里露线的原因分析及解决措施

分析全钢工程机械子午线轮胎胎里露线的原因,并提出解决措施。通过采取确保成型机平宽与带束层贴合鼓周长合理、缠绕机挤出胶条尺寸稳定、成型鼓扇形块周长一致、防止垫胶贴合偏歪、内衬层接头压实、合理设定硫化定型压力等措施,有效解决了胎里露线问题。

电镀镀层对帘线黏合剥离性能影响

为研究电镀钢丝镀层对帘线黏合和剥离性能的影响,分别生产不同镀层重量、镀层铜含量和镀层表层铜含量的Φ1.72 mm电镀黄铜钢丝,以相同工艺拉拔捻制为2×0.30 HT钢帘线,用以帘线和橡胶黏合和剥离性能测试。结果发现:当帘线镀层重量在2.47~4.34 g·kg^(-1)、镀层铜含量在61.30%~66.36%时,帘线和橡胶建立了良好的黏合强度和黏附效果,即帘线和橡胶在此范围具有较好的黏合和剥离性能,钢丝表层铜含量在57.82%~62.22%时,帘线与橡胶的黏合和剥离性能均良好,说明此范围内表层铜含量的变化未对帘线黏合和剥离性能造成明显的或不利的影响。同时,当钢丝铜含量或表层铜含量偏低,均使得拉拔损失增加,不利于钢丝拉拔。

电镀电流密度对2×0.30HT钢帘线黏合及剥离性能影响

为研究电镀铜过程对钢帘线黏合和剥离性能的影响,以直径1.80 mm钢丝为基础,分别生产不同平均电流密度、槽间电流密度分布及最外层电流密度因素下电镀钢丝,以同机床、同工艺拉拔捻制为2×0.30HT钢帘线,分别考察3因素钢帘线的黏合和剥离性能。结果表明:电镀铜平均电流密度、各阳极架电流密度分布不均以及最外层电流密度在一定范围内变化对钢帘线黏合抽出性能影响较小,但随着电镀平均电流密度增大至17.07 A/dm~2,镀层致密性变差,从而使得钢帘线的剥离性能降低;同时,相比于钢丝最外层电流密度的设置,首节阳极架电流密度过高更容易导致钢帘线的剥离性能不良。

基于泰伯挺度仪的钢丝/钢帘线弯曲刚度分析与仿真模拟

弯曲刚度对轮胎、橡胶减震器等橡胶/钢帘线复合材料的抗变形能力至关重要。采用泰伯挺度仪对钢丝及钢帘线的弯曲刚度进行测试分析。基于泰伯挺度仪测试方法分析泰伯挺度仪测试原理,通过ABAQUS有限元软件对钢帘线的弯矩测试进行模拟,分别设计并建立了推辊模型、端面翻转模型和挡片模型三种有限元模型,并将模型所计算的结果与实测结果进行比较。该模型可有效辅助钢帘线的设计,缩短研发周期,节约成本。