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 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.

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.

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.

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.

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.

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.

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。

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。

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。

帘线钢XLX72 A中氧化物夹杂的演变解析与去除

针对φ0.175 mm及以下规格细丝帘线钢夹杂物演变控制与去除问题,通过采用Si-Mn脱氧、造碱度为0.7~1.0的精炼顶渣和30 min以上的软吹等过程工艺,对帘线钢中的夹杂物进行转变控制和去除的试验研究。试验结果表明,LF精炼过程钢中夹杂物数量不断增加,软吹过程中,夹杂物数量先快速减少,软吹到30 min时减少到了2~3个/mm^(2),继续软吹时夹杂物数量略有增加;而LF精炼和软吹过程钢中的氮含量不断增加,全氧含量不断下降,上连铸时钢中的氮含量为0.0034%~0.0038%,全氧含量为0.0012%~0.0014%,最终得到夹杂物数量不超过3个/mm^(2),钢水上连铸时氧化物夹杂尺寸<10μm,且没有氮化钛(TiN)夹杂和纯Al_(2)O_(3)夹杂或高Al_(2)O_(3)含量的夹杂,完全满足用户的使用要求。

全钢载重子午线轮胎胎圈露线的原因分析及解决措施

从产品设计和工艺控制方面分析全钢载重子午线轮胎胎圈露线的原因,并提出相应的解决措施。通过适当增大成型平面宽和鼓肩宽,适当减小钢丝圈内侧胎侧厚度和胎趾角度,严格控制胎侧成型定位、胎坯存放、硫化机机械手精度、钢丝圈缠绕工艺及存放等措施,有效地解决了全钢载重子午线轮胎胎圈露线问题,提高了轮胎的安全性能,降低了生产成本。

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。

钢丝帘线/橡胶复合材料弯曲疲劳失效机理的研究

自主设计并搭建基于隧道磁阻传感器的无损检测系统,对钢丝帘线/橡胶复合材料试样(简称试样)弯曲疲劳失效机理进行研究。结果表明:无损检测方法可对疲劳试验后试样内部的损伤状态进行评估,无损检测系统可实现试样缺陷的在线检测;疲劳缺陷的产生是损伤累积,钢丝帘线单丝断裂主要发生试样疲劳寿命的最后阶段;试样内部钢丝疲劳断裂为穿晶解理断裂,裂纹扩展过程中存在一定程度的微观不连续性,包括多次角度偏折与裂纹分支;试样内部钢丝疲劳断口具有典型的低周疲劳特点,存在多个疲劳源与撕裂台阶,疲劳源间偶见撕裂棱,无明显贝纹样,疲劳源附近表面光滑,断口形成了较平滑的微撕裂形貌与粗糙的撕裂台阶形貌。

基于DCGAN和改进YOLOv5s的钢丝帘布缺陷检测方法

为解决钢丝帘布表面缺陷检测准确率低且泛化能力不强的问题,提出了一种基于DCGAN和改进YOLOv5s的缺陷检测方法。首先,通过调整DCGAN网络参数并优化超参数,使生成器能够生成具有丰富特征和清晰纹理的钢丝帘布缺陷图像,从而扩充数据集;其次,采用K-means++算法对钢丝帘布缺陷数据重新聚类锚框,以获得更优的锚框参数,实现锚框与实际缺陷的精确匹配;然后,在YOLOv5s主干网络中的C3模块添加坐标注意力机制,以增强模型的特征提取能力和精确定位能力;最后,引入MPDIoU损失函数替换YOLOv5s原损失函数,进一步提高检测精度。实验结果表明,在实测钢丝帘布缺陷数据集上,采用DCGAN数据增强和改进后的YOLOv5s检测模型,缺陷检测平均精度提高了6.6%,达到了89.4%,并且检测准确率和召回率也有所提高。与其他主流检测模型相比,该模型不仅在检测速度上提高了约30%,还保持较高的检测精度。在公开的NEU-DET数据集上,该模型的mAP值达到了82.6%,较原始YOLOv5s模型提高了3.8%。

巨型工程机械子午线轮胎钢丝帘布裁断机导开装置的设计

介绍一种巨型工程机械子午线轮胎钢丝帘布裁断机的导开装置,并对其结构设计特点、电气和气压传动控制技术进行阐述。该导开装置具有导开功能、纠偏功能、摆动接料功能和异物检测功能,采用可编程逻辑控制器技术和气压传动技术,智能化程度较高,可以解决上料难、钢丝帘布跑偏等问题,减轻劳动强度,提高工作效率。