无取向硅钢热轧卷结疤缺陷产生的原因及控制

针对不同牌号的无取向硅钢产生结疤缺陷的难易程度和表面结疤缺陷的外形特征及分布规律,分析了该缺陷产生的原因。通过调整剪前导板的对中度,设置精轧侧导板开度余量及短行程数值,及时修补与更换侧导板,减少带坯与侧导板挤撞程度,有效地降低了结疤缺陷发生率。     

热轧带钢边部结疤缺陷分析及控制

针对武汉钢铁有限公司热轧厂带钢边部结疤问题,通过带钢表面检测数据统计,结合实物缺陷宏观形貌观察,将边部结疤分为蝌蚪状结疤、折叠状结疤、坑状结疤及条状结疤4类;对各类结疤取样后进行金相显微观察和扫描电镜分析,并结合炼钢、热轧生产工艺调查分析,找出了各类结疤的产生原因。通过采取热轧精轧侧导板控制、连铸二次冷却工艺优化、铸坯火焰清理控制及结晶器精度控制等措施,将热轧带钢边部结疤发生率由15.2%降低到0.29%。     

热轧板结疤缺陷成因分析

对热轧板结疤缺陷和冷轧板成串孔洞缺陷进行取样,金相分析认为具有黑色纤维状组织的疤皮部分是钢基受撞后的分离物.现场观察发现了钢板撞击精轧机组侧导板现象.移植结疤缺陷进行热、冷轧模拟轧制实验,再现了结疤缺陷的生成、演变过程.分析认为钢板撞击精轧机组侧导板是产生结疤缺陷的原因,而冷轧板成串孔洞则是结疤缺陷的遗传产物.避免钢板撞击精轧机组侧导板是消除结疤缺陷提高热轧板材质量关键因素之一.     

热轧精轧机侧导板标定装置及标定方法

精轧机前侧导板在生产中需要周期性进行宽度位置标定,以保证侧导板宽度精度。针对1780热轧带钢生产线精轧侧导板标定异常情况进行分析与研究,研发了一种简便、可靠、安全的标定装置及标定方法。该标定装置及方法解决了原有标定装置及方法存在的测量不精确、有中间计算环节,侧导板匡量影响难以消除的问题。     

热连轧精轧机侧导板结构优化

八钢1750mm板带热连轧生产线中,由于粗轧中间坯头部跑偏顶撞精轧F1侧导板,导致废钢和顶坏设备。对F1机架侧导板原整体结构的设计优化,在侧导板喇叭段前增加变斜度导引板改进实施后,使导引板喇叭开口度完全覆盖了带钢头部跑偏量,同时保证了原有侧导板功能和换辊的需要,杜绝了此类轧废事故,降低成本费用,提高了生产作业率。     

热轧带钢“翘皮”缺陷产生原因及预防

针对唐钢不锈钢公司1580生产线热轧带钢边部"翘皮"质量缺陷,进行了电镜扫描和能谱分析,确定了缺陷的产生的原因。从连铸工序、加热制度、粗轧立辊压下制度和精轧侧导板系统进行了改进,并进行实际跟踪验证。结果表明,加热制度和立辊调宽量对"翘皮"缺陷的发生率有较大影响,通过对现有工艺制度进行修订,有效降低了"翘皮"缺陷的发生。     

热轧带钢精轧侧导板结构改进及对中控制方案优化

热轧带钢精轧机组侧导板是保证精轧生产稳定性的重要设备,其使用状态及控制策略的好坏将直接影响轧件的稳定运行。通过对热轧带钢精轧机组侧导板磨损规律的研究进行侧导板结构的改进,解决了更换困难造成的磨损超标状态下使用的问题,同时考虑不同尺寸成品的生产条件的不同,对精轧机组侧导板对中控制方案进行了优化,从而总体保证了精轧机组侧导板强制对中功能的正常发挥。     

热轧带钢表面丝状异物压入原因分析及预防措施

文章介绍了八钢1750热轧厂在前期的生产过程中出现的带钢边部丝状异物压入缺陷的情况。通过对轧线工艺通道的检查以及缺陷形貌的分析比较,找出了造成缺陷的原因并提出针对性措施:增加机架间逆喷水、更改侧导板衬板材质、优化侧导板开口度修正值等,提出了清洁生产的需求,多措并举减少了带钢异物压入的缺陷率,提高了产品质量。     

提高2032热轧线冷轧基板质量的实践

分析造成2032热轧线生产的冷轧基板存在厚度、宽度、浪形等协议板的原因是:温度控制、厚度波动、浪形控制、表面除磷等,介绍实施的改造精轧侧导板和液压活套与增加F6液压弯辊等措施。     

高强钢SFB700热轧板形缺陷的成因及控制措施

分析3.0～6.0 mm厚规格的SFB700热轧板边部浪形缺陷的形成原因,主要在于轧制精轧出口板型控制边浪趋势,与带钢在轧后冷却时边部冷却不均有关。通过优化精轧板形控制策略、调节层冷区域两侧水量差及侧喷水角度减少边部浪形缺陷的产生,并采用新的平整工艺有效消除边部浪形,显著降低了SFB700边浪缺陷的发生率。     

带钢热连轧机生产TA10钛合金带的轧制工艺

在带钢热连轧机组上开展TA10钛合金带的轧制工艺优化研究,结合带钢轧制工艺设计,提出多组不同钛带轧制工艺规程,然后直接在带钢热连轧机上进行TA10钛合金带的热连轧生产试验。通过比较研究不同轧制工艺所生产产品的微观组织、力学性能及其他质量状态,揭示了不同热连轧工艺与组织性能的相关性,掌握TA10钛合金带热连轧变形特点,优选确定了TA10钛合金带的轧制工艺及参数,并投入生产应用后使该带钢热连轧机稳定生产出了基本满足相关技术标准要求的TA10钛合金带产品。     

热轧板带板形检测发展分析

分析了国内外热轧板带的板形检测技术及几种板形检测方法的发展应用状况,并就热轧板带产 品的发展及要求展望了未来板形检测的发展方向。     

Roll Wear Evaluation of HSS,HiCr and IC Work Rolls in Hot Strip Mill

While it is acknowledged that roll wear is one of the most challenges to hot strip mills (HSM), very few studies which detail an exact prediction model have been published. The aim of this work is to evaluate and compare two prediction models with measured roll wear. The first prediction model, model 1, developed for a plate mill, was modified to use in strip rolling process. The second prediction model, model 2, is a simplified on‐line model. Data of two hot strip mills were used to investigate the influence of different rolling schedules. The rolls and strip properties were described and the rolling conditions were detailed. The influence of hot rolling factors, such as strip strength, roll grades, rolling temperature, rolling force, reduction and contact length, were also studied. When rolling with different work roll materials and strip grades, the modified prediction model has better prediction accuracy than the simplified model. The accuracy of both models becomes better at higher roll wear > 150 μm. HSS work rolls were confirmed to exhibit improvement of roll wear in comparison with HiCr rolls, the wear resistance was 3 to 4 times better. The influence of strip grade on roll wear was shown to be significant, with higher accuracy of the regression statistics for rolling with similar strip grades and lower regressed accuracy for rolling with mixed strip grades. The roll wear was evaluated at the centre of the barrel.     

取向硅钢冷轧断带问题研究

对取向硅钢冷轧过程出现的断带缺陷进行了跟踪,明确了从起皮到形成孔洞,再到断带的演变过程,采用扫描电镜对翘皮缺陷进行研究,结果表明：翘皮缺陷中主要元素是Fe、Si、Al,与基体一致,另外还有微量的Ca、Mg、K、Na等元素。冷轧起皮、断带主要是由于热轧边裂缺陷遗传而成。热轧过程部分边部掉肉飞溅至热轧板表面被压入,在冷轧过程由于伸长率与基体不一致而起皮剥落。通过降低铸坯加热温度、缩短高温段在炉时间、优化轧制模型,有效抑制了热轧板边裂的产生,从而解决了冷轧断带问题。     

Surface inclusions and their evolution on strip rolled on CSP line and in following cold rolling process

Abstract

Hot and cold rolled strip samples with surface defects such as black pockmark, sliver and central cracking were collected from a compact strip production line followed by cold rolling. Microstructures and chemical compositions of the strip with defects were studied by scanning electronic microscopy and energy dispersive X-ray spectroscopy. Four typical types of defects on strip including surface spherical mould powder entrapment, centre spherical mould powder entrapment, surface linear mould powder entrapment and centre linear mould powder entrapment were studied by hot and cold rolling experiment in laboratory. It was observed that spherical mould powder entrapment was transformed into the surface black pockmark after the hot rolling and cold rolling process. Centre spherical mould powder entrapment led to central fracture in the hot and cold rolling process. Surface linear mould powder entrapment resulted in sliver and centre linear mould powder entrapment led to severe sliver.     

热轧带钢亮带/冷轧带钢凸棱的成因及解决措施

 针对冷轧带卷的凸棱缺陷,对冷轧生产工艺进行适当调整,未能完全消除;而同期热轧带钢表面出现了亮带,经过跟踪与测量,确定热轧卷亮带位置与冷轧卷凸棱位置有对应关系,并提出亮带的实质是轧辊的猫耳状不均匀磨损导致在带钢厚度方向上形成的局部高点。通过优化热轧轧辊辊型和其他工艺制度,成功地解决了中薄板坯连铸连轧生产线上热轧带钢亮带问题,同时避免冷轧带钢凸棱缺陷。     

Slow Hot Rolling in Direct Linkage with Thin Slab and Strip Continuous Casting: Effect on the Evolution of Austenite Grain

This work was carried out in context with the development of strip casting with the single‐belt process. In this new process the hot rolling is performed in‐line with considerably lower velocity than in conventional hot rolling. It is of interest to study the effect of low rolling speed on the material properties. Based on a finite element model used to predict the thermomechanical behaviour of the strip in tandem mills, the microstructural evolution of austenite was computed. In order to take account of the non‐isothermal conditions in industrial hot rolling, the material equations for recrystallization and grain growth are modified. The parameter studies were carried out over a wide range of volumetric flow rate extending from that in thin slab casting to that in conventional finishing rolling. They demonstrate that the “slow hot rolling” can produce a fine grain of austenite. Austenite grain evolution was computed for conventional rolling with a seven stand mill and for in‐line hot rolling of strip produced by the single‐belt process. It is found that the final grain size of austenite is about the same for the two processes under the condition that strip thickness behind the last stand is the same.     

基于案例学习的PC轧机板形智能设定方法

热轧板形模型大都建立在大量简化与假设基础之上,计算精度存在瓶颈。借鉴聚类分析和案例学习等数据挖掘方法,利用历史数据建立热轧板形PC角设定案例库,提出一种热轧板形PC角的智能设定方法。首先,对大量轧制历史数据进行聚类分析,挖掘出带钢板形控制良好的轧制案例,建立一个初始的轧制案例库。接着,在日常生产中不断对该案例库进行迭代学习,将更优秀的轧制案例分层别更新到案例库;使用时,通过相似度计算从案例库中找到与当前带钢最接近的轧制案例,取出其对应的PC角进行在线板形设定。该方法已成功应用于宝钢1580热连轧机组,在线应用表明可以有效提高热轧带钢板形控制精度。     

热轧带钢轧机无头轧制技术简介

介绍了最新发展的热轧带钢轧机无头轧制技术，在传统热轧带钢生产线上，采用成熟的热卷取箱轧制技术，进而实现热轧带钢中间坯头尾对焊后的无头轧制，可以提高薄带钢轧制的稳定性，提高带钢头尾部的尺寸精度。该技术将是传统式热轧带钢生产技术发展的新动向。