Application of statistical methods to reveal and remove the causes of welding of coil laps upon annealing of cold-rolled steel strips

The factors of the process of production of cold-rolled steel strips that promote and hinder the appearance of a coil lap welding defect upon annealing in bell-type furnaces are analyzed using statistical methods. The works dealing with this problem are analytically reviewed to reveal the problems to be studied and refined. The ranking of the technological factors according to the significance of their influence on the probability of appearance of this defect is determined and supported by industrial data, and a regression equation is derived to calculate this probability. The process of production is improved to minimize the rejection of strips caused by the welding of coil laps.     

Recrystallization of a cold-rolled low-carbon steel by cold-plasma-discharge rapid annealing

A new annealing technology has been developed by the authors in order to conduct fast steel annealing. This process consists of steel heating by cold-plasma discharge. It allows the opportunity for new annealing cycles with higher heating rates (up to 300 K/s), shorter soaking times, and controlled cooling rates, so that well-recrystallized samples have been achieved in less than several seconds of total process time. This article reports the influence of various parameters of the annealing cycle (heating rate, maximum annealing temperature, and cooling rate) on the recrystallization and properties of a cold-rolled low-carbon steel. This study shows that the annealing time can be significatively reduced using this new technology, compared to the industrial continuous annealing technology used today, to obtain equivalent metallurgical properties.     

罩式炉装配炉的自动化与程序设计

针对喷淋冷却罩式炉机组人工装配炉存在的问题，提出通过计算机自动计算装配炉来减轻劳动强度的设计程序，并通过自适应的方法反映炉台状态、冷却水温度和加热罩能力的变化，及时调整相关参数，精确搭配退火钢卷的钢种、规格，减少待罩时间，提高罩式炉产量。     

控轧控冷工艺对X80管线钢强度影响的统计分析

重点分析了X80管线钢在控轧控冷过程中工艺对于屈服强度、抗拉强度的影响。通过大生产试验和数据回归,进一步分析出影响X80管线钢强度的主要因素,其中影响屈服强度主要因素为终轧温度、终冷温度,与其呈负相关;而冷却速率和Mo含量与其呈正相关。同时,影响抗拉强度的主要因素为终轧温度和终冷温度,与其呈负相关;而冷却速率、Mo含量和碳当量则与其呈正相关。最后得出了各个影响因素对强度影响的经验公式。     

冷轧薄板再结晶温度研究

冷轧薄板的生产过程中,金属晶粒经过冷变形,晶粒将随着变形方向拉长。这种变化将导致力学性能等的变化。再结晶退火是冷轧薄板生产过程中的一个重要过程。因此,研究冷轧薄板再结晶温度以及压下率对再结晶温度的影响,对冷轧薄板生产具有重要的实际意义,能够为冷轧薄板生产时退火工艺制度的制定提供理论依据。     

强对流高氢罩式退火技术在钢丝热处理上的应用开发

用于钢丝拉拔后的中间退火、轧制前的球化退火及轧制后消除应力退火的宝钢研发的强对流高氢罩式退火炉,采用了抽真空换气技术、脉冲燃烧技术和合理的炉内气流导向装置,具有产量高、运行成本低、炉温均匀、退火后产品质量优良等特点.     

影响SPHC酸洗效率因素分析及解决措施

分析了影响冷轧基料SPHC酸洗效率的因素,从钢水残余元素控制、层流冷却方式、开轧温度、卷取温度、润滑技术等方面采取有效措施。结果表明,热轧带钢表面质量良好,冷轧酸洗效率得到提高,赢得了客户的认可。     

浅谈针压的影响因素

在冷轧不锈钢的生产过程中,产生表面质量问题主要是在冷退酸洗工序中,而退火工艺中最常见的就是钢带表面出现的针压。由于退火炉内的钢带在高温下表面硬度较低,与黏附在支撑辊上的异物接触后,产生针压。通过对产生原理的分析,对支撑辊材质、周期、传动方式以及工艺参数调整对针压影响的研究,制定出相应有效的对策,减轻了针压缺陷的发生,大大改善了产品的表面质量。     

热镀锌IF钢板生产工艺的研究

介绍了热镀锌IF钢版生产工艺的的流程和工艺参数,以及热镀锌工艺参教对热镀锌IF钢板形成性能的影响。     

退火温度对430不锈钢冷轧板组织和力学性能的影响

针对现场生产的430不锈钢冷轧板,通过高温连续退火实验研究了退火温度对材料显微组织、强度、塑性以及各向异性性能的影响.通过实验得到了合理的两段式加热连续退火工艺:选取中间温度为600℃,加热II段的加热速率为2.3℃·s-1,最高加热温度为840℃.随着退火温度的升高,薄板的屈服强度和硬度呈明显的两阶段降低趋势,延伸率呈"S"型趋势增加,平均塑性应变比基本保持不变（1.25左右）,而轧制平面各向异性指数有一定的降低.针对430不锈钢冷轧板分别建立了屈服强度与退火软化率和延伸率之间的定量关系.      

罩式退火过程中温度场对08Al冷轧钢带再结晶影响的分析

温度是罩式退火过程中的一个重要参数.结合我厂冷轧08AL带钢在罩式炉退火的实际过程,以实验为基础,对同一炉台的退火周期进行多点温度测量.得出各阶段钢卷温度分布规律,分析退火温度变化对再结晶的影响,对优化罩式退火工艺具有指导意义.     

二次冷轧的中间退火温度对2.3Si无取向硅钢组织和性能的影响

试验2.3Si无取向硅钢(/%:0.003C,2.30Si,0.16Mn,≤0.020P,≤0.005S,0.54Al)冷轧板由常化和未常化的2.5 mm热轧板冷轧至0.6 mm(压下率76%),经750~950℃ 2.5 min中间退火后再冷轧至0.5 mm(压下率16.7%),成品板经890℃+960℃ 2.5 min退火。研究了中间退火温度对该钢晶粒尺寸、织构和磁性能的影响。结果表明,随中间退火温度的升高,二次冷轧前晶粒和成品晶粒增大,成品中不利织构组分{111}和{112}减弱,磁性能得到改善。热轧板经过常化时的磁性能明显好于未经常化时的磁性能,但中间退火温度较高时常化对磁性能的有利作用减弱。     

卷取温度对冷轧SPCD钢组织与性能的影响

为了研究不同卷取温度对CSP-K,艺生产的SPCD冷轧成品板的影响,采用两种卷取温度（其他的热轧、冷轧、退火工艺都相同）生产了1、2号的冷轧SPCD试验板,并通过单向拉伸试验对两种钢的基本成形性能（r值、n值）和力学性能指标（屈服强度、抗拉强度、伸长率）进行了测定。对比分析发现,卷取温度对SPCD冷轧板的成形性能影响显著,其主要原因为卷取温度能影响最终SPCD成品板的自由氮含量。     

Creation of an Effective Technology for the Production of Cold-Rolled High-Strength Low-Alloy Steels with High and Stable Properties. Part 2. Cold-rolled Products

Metallurgist - The structural state and mechanical properties of cold-rolled steel of strength class 340 MPa or grade HC340LA of the current production, annealed in bell-type furnaces, were...     

A comparative experimental and numerical study to investigate the relative merits of convectors and “C” inserts in cooling cold-rolled coils

The coil cooling and storage unit (CCSU) is used to cool cold-rolled coils to the temper rolling temperature after the annealing cycle is over at the batch annealing furnace (BAF) in a cold rolling mill (CRM). In the CCSU, the coils are kept on the cooling bases for any fixed time irrespective of the grade and tonnage. Therefore, the need for a mathematical model to accurately predict the cooling time of the coils was felt. The current study involves experimental and numerical analysis of a stack of coils with respect to heat transfer and fluid flow. A comparative study was carried out to ascertain the relative merits of convectors and “C” inserts (CIs) in the cooling the coils. The air flow distribution for the case of different convectors and CIs was measured by means of a full scale physical model. Two different mathematical models were applied to model the fluid flow and flow distribution through the stack of coils. The first flow model uses the hydraulic resistance concept for estimating the air flow rate distribution, whereas the second flow model uses commercial computational fluid dynamics (CFD) software and predicts the velocity distribution in the flow path between two coils in a stack. The predictions from these two models compare well with the experimental data. The flow models were used to calculate the average heat-transfer coefficient in different flow passages in a stack. The heat-transfer coefficients thus obtained were used to tune and validate a two-dimensional transient heat-transfer model of coils. The heat-transfer model predicts the cooling time of coils accurately and also suggests a possible reduction of cooling time if CIs are used in place of convectors.     

HC340LA钢冲压“桔皮”缺陷成因及措施

分析了340 MPa级冷轧低合金高强度钢“桔皮”缺陷钢板和正常钢板的微观组织结构和力学性能。结果表明,缺陷钢板的应力-应变曲线屈服点伸长率达到了3.73%,屈服延伸过大导致了所冲压的前风窗横梁连接板表面产生“桔皮”缺陷。在实验室采用对钢板预拉伸的方法模拟钢板工业化生产的平整与拉伸矫直工艺,随着预拉伸量的增加,试验样屈服平台的长度减少,当预拉伸量超过1.8%时,试验样的屈服平台消失。微观组织进一步分析显示,退火温度高导致钢板晶粒粗大和晶粒取向异常是冲压钢板 “桔皮”缺陷产生的根源。在连续退火工艺环节中合理控制平整和拉伸矫直工艺可以消除或者缩短试验钢屈服平台长度,并避免冲压件表面“桔皮”缺陷发生。     

冷轧SPCC钢种退火工艺制度的优化

介绍了从奥地利引进的全氢罩式退火炉的特点,结合唐钢冷轧厂的生产实际情况,分析了影响退火工艺的多种因素,对主要产品SPCC钢种的退火工艺制度进行了优化,退火周期缩短了4—6h,机组月产量提高12．1％,产品合格率由95．5％提高到98％以上。     

国产不锈钢全氢罩式退火炉的关键技术及实现

将自主开发的关键设备和成套控制系统与软件应用到国产不锈钢全氢强对流罩式退火炉机组,考虑到不锈钢退火炉温度高的特点,对罩式炉关键部分进行了优化设计,同时采用了国产的关键零部件。实践表明,不锈钢罩式退火炉运行安全可靠,各项技术指标均达到设计要求。     

3#电工钢机组带钢板形的控制与改善

冷轧电工钢产品除了对磁性能有较高需要外,对带钢的浪形也有很高的要求.电工钢连续退火涂层机组由于退火温度高,带钢在退火过程中会产生浪形,严重时会影响产品的正常使用.在分析带钢浪形的影响因素的基础上,3#电工钢机组采用控制带钢冷却速度、改进缓冷段风箱结构和挡板控制方式、减少退火炉入口带钢跑偏等措施来控制浪形的发生.在生产过程中,取得了良好的浪形控制效果.     

提高全氢罩式退火带钢机械性能一致性方法研究及应用

强对流全氢罩式退火炉在碳钢、低合金钢的冷轧带钢生产上应用很广泛。随着金属制品行业竞争的加剧,客户对带钢组织性能的均匀性提出了更为严格的要求。从材料装炉、温度控制、气氛控制三个方面进行分析,就如何提高强对流气体保护燃气退火材料均匀性提出基本方法,应用效果表明了该方法的可行性。