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1.
荫罩框架钢冷轧薄板边部线状缺陷研究   总被引:8,自引:2,他引:6  
边部线状缺陷是影响荫罩框架钢冷轧成品质量的表面缺陷之一。对荫罩框架钢生产工艺,设备进行全面调研,对缺陷宏、微观特征和缺陷中氧化圆点点形成机理做了深入的分析研究。研究结果表明,荫罩框架钢冷轧板边部线状缺陷是高温钢坯在热轧粗轧工序划伤后,将氧化铁皮压入沟槽内,在后续的轧制过程中逐渐演变而成。采取有效措施后,使缺陷卷比例由85%下降到7%以下。  相似文献   

2.
针对600MPa级冷轧高强钢生产中出现翘皮缺陷的质量问题,进行了现场跟踪、确认,利用金相检验、电镜观察和能谱分析等检测手段对冷轧高强钢的翘皮缺陷试样进行分析。结果表明:翘皮缺陷主要分布在带钢边尾部,距离其边部30~40mm,纵向无显著规律;在翘皮处的基体表面及横截面发现保护渣的成分元素,这是由于连铸工序中结晶器保护渣卷入铸坯表层,经过轧制变形,中间坯角部低温区在一定的立辊侧压作用下产生变形形成裂纹,在随后的变形过程中,轧制不能消除裂纹,最终形成沿轧制方向的翘皮缺陷。  相似文献   

3.
介绍了唐钢1580生产线生产J55石油套管用钢的工艺流程、产品性能及钢卷表面出现翘皮缺陷的现象。通过对比分析,查明产生翘皮缺陷的原因主要与连铸过程的工艺控制有关,连铸拉速的波动导致板坯表面微裂纹和重皮的形成,轧制后即在钢卷对应区域产生翘皮缺陷。粗扎立辊轧制力的大小不是造成翘皮缺陷的主要原因,但对翘皮的严重程度有一定的影响。  相似文献   

4.
条状缺陷是IF钢冷轧板常见的表面缺陷之一,针对邯钢IF钢冷轧板表面出现的条状缺陷,分析了该类条状缺陷的成因,并提出了合理的控制措施。通过SEM-EDS分析发现条状缺陷内部存在大量的小尺寸Al_2O_3颗粒,分析其来源于铸坯中大型Al_2O_3夹杂物。对不同浇注阶段铸坯进行SLIME法大样电解并采用SEM-EDS分析其大型夹杂物类型,发现在交接坯和换水口坯中存在较多的大型Al_2O_3夹杂物,分析其来源为水口结瘤物。综合分析后得出此类条状缺陷成因是水口结瘤物脱落被卷入结晶器,并在铸坯中形成大型Al_2O_3夹杂物,进而在冷轧板轧制过程中形成表面条状缺陷。  相似文献   

5.
文章对HN700 mm×300 mm型钢轧制缺陷产生的原因进行了分析,并提出了消除轧制缺陷的方法。通过减少轧制缺陷,提高了HN700 mm×300 mm型钢的成材率,并将消除HN700 mm×300 mm型钢轧制缺陷的经验运用到其它规格H型钢的生产中。  相似文献   

6.
冷轧IF钢表面翘皮缺陷是影响钢卷成材率的主要因素.通过选取典型翘皮缺陷试样,利用金相显微镜、扫描电镜及能谱等实验手段对翘皮缺陷试样进行了分析.结果表明:沿轧制方向呈条状分布的翘皮缺陷是由于连铸浇注时Al2O3夹杂物脱落所致.通过采取优化顶渣改质、严格控制大包下渣、合理控制塞棒吹氩量、优化浸入式水口插入深度等措施,汽车用...  相似文献   

7.
对八钢小型轧机轧制热轧抽油杆用圆钢易产生表面缺陷的原因进行了分析 ,介绍了实践操作中存在的问题 ,并制定出相应解决办法 ,确保热轧抽油杆用圆钢的质量要求。  相似文献   

8.
45Mn2钢厚壁无缝管分层缺陷分析   总被引:1,自引:0,他引:1  
常宏伟  李延春 《鞍钢技术》2010,(3):37-39,44
对生产45Mn2钢厚壁无缝管时产生的分层缺陷进行了分析,认为钢管产生分层缺陷与钢坯本身的塑韧性有关,同时不同的穿孔工艺对无缝管产品质量也有显著影响。采取相应措施,如提高管坯的塑韧性、确定合理的管坯加热温度、选择合适的轧制工艺、降低轧制速度等,可减少厚壁无缝管分层缺陷的发生率。  相似文献   

9.
大断面方钢的圆角尖锐和坯型脱方缺陷会对用户的进一步加工造成损害.分析并在实际生产中验证了此类缺陷的产生原因,同时研究了此类缺陷的控制方法.减少2#机无槽轧制压下量可保留1#机有槽轧制形成的圆角,适当增加进孔型轧制的宽度等方法可提高轧制稳定性.通过实施改变轧制规程、优化轧制操作等措施,可以消除圆角尖锐和坯型脱方缺陷,满足用户使用要求.  相似文献   

10.
文章针对现场生产的某批高强度液压油缸用无缝钢管表面缺陷引起的返废率高的问题进行了分析研究,通过分析缺陷形貌将其分为结疤、凹坑和麻面三大类。通过金相、扫描电镜等分析方法对各类缺陷进行了检测分析。结果表明,结疤、凹坑缺陷的形成是由轧制前原始坯料已经存在的表面裂纹引起的,麻面缺陷的形成是热轧过程中表面氧化铁皮被轧压至管体上产生的。为了消除上述缺陷,有针对性地采取了整改措施,优化了连铸和轧制工艺。整改后的产品表面质量大幅度提高,返废率从30.6%降低到了1.7%。  相似文献   

11.
转炉炉壳热应力分析   总被引:5,自引:1,他引:4  
任学平  郭志强  邹家祥 《炼钢》2001,17(6):47-49
根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。  相似文献   

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13.
通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。  相似文献   

14.
Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.  相似文献   

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16.
Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

17.
The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.  相似文献   

18.
Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.  相似文献   

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