共查询到20条相似文献,搜索用时 156 毫秒
1.
针对唐钢FTSC薄板坯连铸连轧线生产SS400热板卷的轧制孔洞缺陷,对连铸坯的低倍组织、铸坯温度分布和动态软压下工艺进行了研究。结果表明:铸坯存在内部横裂纹和疏松缺陷,内部裂纹产生在0扇形段,裂纹处硫元素呈正偏析;铸坯内部裂纹和疏松缺陷在后续轧制中不能够焊合,是导致轧制孔洞缺陷的直接原因。通过优化动态软压下参数,将压下终点向前提和减小0扇形段的压下量;增加二次冷却强度,提高冷却均匀性;提高钢水质量、加强设备精度管理和推进恒拉速操作,可以完全避免中碳钢SS400热轧板卷轧制孔洞缺陷的产生。 相似文献
2.
通过对莱钢宽厚板连铸机铸坯中间裂纹缺陷的研究分析,总结出钢水中碳、锰元素与中间裂纹产生几率的关系,认为扇形段辊缝精度和二冷强度是影响铸坯中间裂纹的关键因素,良好的辊缝精度和喷嘴状况能够有效避免铸坯中间裂纹的产生,钢水过热度和拉速等连铸工艺条件也是中间裂纹的产生因素,并根据裂纹产生的原因制定了整改措施。 相似文献
3.
4.
经过对产生内部裂纹的连铸板坯试样进行系统的检测分析研究,找出了连铸板坯产生内部裂纹的主要原因是铸机扇形段弧线与拉矫机弧线对中不好,导致矫直过程中铸坯受力不均匀而产生内部裂纹。采取对铸机扇形段进行调整对弧的措施,使连铸板坯的内部裂纹出现率大大降低。 相似文献
5.
对涟钢生产的Q235B等中碳钢板坯在热轧过程中出现板卷表面结疤缺陷进行了研究。采用金相显微镜、扫描电镜和能谱分析对铸坯角部裂纹进行检测分析,结果表明扇形段矫直区间铸坯温度控制不合理是铸坯产生角部裂纹的主要原因。 相似文献
6.
7.
3.内部裂纹连铸方坯的内部裂纹可分为中间裂纹、中心裂纹、角裂纹和边裂纹四类。中心裂纹产生于铸坯断面的中心,它以距铸坯表面75~80mm 的位置为其外侧起点,穿过铸坯中心的柱状晶区,沿平行于铸坯的浇铸方向产生。中间裂纹多发生于铸坯的两个侧面,对应地分布于中心裂纹的两侧,其裂纹形态和中心裂纹极其相似。边裂纹多产生于距铸坯表面25~45mm 处, 相似文献
8.
针对炼钢厂铸机扇形段寿命随着高强度钢的生产日益降低的问题,采用数值模拟的方法对铸机浇铸高强钢过程中的铸坯凝固传热和凝固收缩问题进行研究,利用钢种的热膨胀系数对铸坯自由凝固收缩变形行为进行分析。通过计算分析发现钢种的凝固收缩特性与其相变过程的质量密度密切相关,利用铸坯温度场和钢种热收缩特性研究铸坯在铸机扇形段内厚度方向的收缩,优化扇形段辊缝设置。通过调整辊缝调整适应铸坯缩量,减少铸坯对扇形段负载,降低拉坯阻力。通过以上措施的应用,铸机扇形段更换量得到降低,水平段更换量降低了32%,驱动辊扭矩由调整前的25.15%下降到调整后的18.8%。 相似文献
9.
为了更加有效控制和减少连铸坯的角部横裂纹质量缺陷,根据其形成的机制,针对两种新型铸坯模型,即圆角和倒角模型进行研究。通过建立特厚连铸矩形坯在凝固过程的传热模型并进行数值模拟,得到铸坯在凝固过程沿拉速方向上温度场和坯壳厚度的分布规律,并在此基础上建立热力耦合模型,分析铸坯的应力变化,讨论了产生裂纹的可能性。研究结果表明,通过对比传统直角模型,得出圆角和倒角模型对铸坯角部温度场和应力场两个方面的分布状况都有改善,即新铸坯模型角部温度在连铸矫直段有效避开了钢的高温脆性区,同时降低了铸坯角部的应力值,减小了角部裂纹产生的可能性。 相似文献
10.
11.
13.
14.
Haibo Xie Zhengyi Jiang W. Y. Daniel Yuen 《Metallurgical and Materials Transactions B》2011,42(6):1244-1252
Edge cracks in cold rolling of the thin strip affect the strip quality and productivity significantly. In this study, an experimental
and mechanical investigation on microstructures has been carried out to study the edge crack formation during cold rolling
of the thin strip. The effects of the feed material microstructures on the edge crack evolution were studied employing optical
microscopy and scanning electron microscopy (SEM). Experimental observation indicates that fine grain occurs in hot-rolled
microstructure and coarse grain is produced in ferritic rolled microstructure. Different grain sizes affect significantly
the formation mechanics of the microcrack, crack initiation, and orientation of crack extension. The grain size and grain
boundaries effects on crack retardation are discussed also during edge crack initiation. During the crack growth in coarse
grain, most edge crack tips will blunt, which improves the crack toughness by causing less stress concentration. Overall,
the fine microstructure shows a good crack initiation resistance, whereas the coarse microstructure has a better resistance
to crack propagation. This research provides additional understanding of the mechanism of microstructure influence on edge
crack evolution of cold strip rolling, which could be helpful for developing defect-free thin strip. 相似文献
15.
V. A. Nikolaev A. A. Vasil’ev S. S. Pilipenko A. G. Vasil’ev 《Steel in Translation》2017,47(9):623-629
The potential for decreasing the end thickness of hot-rolled strip in traditional broad-strip rolling mills is demonstrated. The change in thickness depends on the temperature difference over the length of the hot-rolled intermediate strip. Additional reduction of the rear end of hot-rolled intermediate strip is worthwhile for other reasons. The rolling of thinner rear ends of hot-rolled strip in continuous cold-rolling mills decreases the loss of metal in end trimming. 相似文献
16.
介绍了天铁集团SPA—H热轧窄钢带的研制开发和生产实践,通过生产工艺优化,解决了铸坯表面凹陷、裂纹,钢带表面氧化铁皮压入、冷弯开裂和个别炉次强度偏低等一系列问题,使钢带各项性能达到用户要求。 相似文献
17.
18.
用金相、低倍和化学检验方法,对3.5mm厚的热轧卷板严重纵裂和折皱废品进行检验分析,认为纵裂和折皱废品是由于板坯加热过程中局部过烧所致,并提出整改措施。 相似文献
19.
Si-qian Bao Yang Xu Gang Zhao Xiang-bin Huang Huan Xiao Chuan-long Ye Na-na Song Qing-ming Chang 《钢铁研究学报(英文版)》2017,24(1):91-96
A grain-oriented silicon steel strip with AlN as main inhibitor was produced by thin slab casting and rolling (TSCR) process.The microstructure, texture and precipitates of the hot-rolled strip were investigated by use of optical microscope (OM), X-ray diffractometer, transmission electron micro-scope (TEM) and energy dispersive spectroscope (EDS).The result shows that the microstructure and texture exhibit a through-thickness gradient similar to that of the hot-rolled strip produced by con-ventional high-temperature slab-reheating process;the preferred orientation varies from{110}<001>in the surface layer to{001}<110> in the center layer, and the Goss texture with a maximum inten-sity mainly concentrates on the surface layer.In addition, some other texture components, for ex-ample rotated Goss texture, form in the 1/4 thickness layer, which are not observed in the hot-rolled strip produced by conventional high-temperature slab-reheating process.The precipitates in the hot-rolled strip are mainly (Mn,Cu)S and AlN compound particles with dimension of 100-200 nm, and the fine precipitates are significantly less than that in the hot-rolled strip produced by conven-tional high-temperature slab-reheating process.Moreover, the areal density of the fine precipitates in the center layer is more than that in the surface layer. 相似文献