PC棒热轧盘条表面结疤原因分析

本文运用铸坯表面酸洗、金相检测、电镜扫描和能谱点分析等技术手段,对热轧盘条表面结疤的原因进行追朔分析,确定铸坯表面存在黑点夹杂物和振痕深是造成盘条表面结疤主要原因,通过采取针对性的措施,消除了盘条表面结疤缺陷。     

焊丝钢ER70S表面结疤原因分析与控制

在Φ5.5 mm热轧盘条ER70S结疤缺陷部位取样进行金相、扫描电镜及电子探针分析,结果表明,结疤处表面裂纹延伸至皮下,裂纹两侧伴有脱碳组织,说明连铸坯料有裂纹、皮下气泡等原始缺陷。铸坯EPMA检测表明,铸坯裂纹处有严重的Sn富集,从而导致了铸坯表面网状裂纹,ER70S盘条结疤主要由铸坯表面网状裂纹引起。通过提高钢水质量、优化连铸工艺等措施,ER70S盘条结疤判次率从5.3%降低至0.3%。     

高碳硬线82B结疤原因分析

为探究引起高碳82B盘条结疤原因,分析了82B盘条结疤处金相组织、夹杂物形貌和夹杂物成分。结果表明:连铸过程中形成的裂纹是引起高碳82B盘条表面结疤的主要原因。     

含硼低碳拉拔材表面结疤机理分析及控制

针对唐钢含硼低碳拉拔材表面结疤现象,利用热力学计算分析了结疤的产生机理,结果表明BN较AlN优先析出,造成晶界脆化,诱发表面结疤。通过严格控制[B]含量在0.0010%~0.0020%,[N]含量≤35×10-6,优化连铸冷却制度等可有效降低盘条表面结疤率。     

高速线材表面结疤原因分析及改进

分析了盘条表面结疤的原因,提出了采用钢坯出炉轧制前去除氧化铁皮、更换轧辊材质、调整轧制孔型的尺寸设计等措施,控制了线材表面结疤的产生,提高了线材的合格率。     

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%。     

热轧盘条常见表面缺陷分析

介绍了热轧盘条常见的各类表面缺陷,结合金相微观分析方法,对盘条不同表面缺陷的典型微观形貌和金相组织形态进行分类与分析,从连铸与轧制工艺角度追溯了盘条表面缺陷产生的原因,提出了相应解决方案。     

82B热轧盘条浅表面网状渗碳体缺陷原因分析

为了研究12.5 mm规格82B的热轧盘条浅表面网状渗碳体缺陷的产生原因,使用光学显微镜对82B的热轧盘条浅表层显微组织进行观测、连铸坯表面铣削后检测浅表层碳质量分数、连铸坯表面剥皮后轧制、使用无碳结晶器保护渣和调整连铸坯加热温度。结果表明,连铸坯浅表层不同深度碳质量分数在凝固偏析的范围内属正常波动,未见明显表面增碳现象;连铸坯浅表层剥掉 3.0～5.0 mm后轧制,82B的热轧盘条浅表面网状渗碳体缺陷仍然存在,没有减少的趋势;使用无碳结晶器保护渣生产的连铸坯轧制成材后,盘条浅表面网状渗碳体缺陷依然存在,且没有减少;把连铸坯开轧温度由890～910调整到960～1 010 ℃后, 82B的热轧盘条浅表面再也没有发现网状渗碳体。综合以上结果,该厂82B的热轧盘条浅表面网状渗碳体缺陷是由不恰当的连铸坯加热温度造成的,而不是连铸坯表面增碳造成的。     

Nb对热轧盘条组织性能的影响

采用C-Si-Mn和C-Si-Mn-Nb两种成分设计,结合高速线材生产的特点开发出了屈服强度345 MPa级高韧性热轧盘条.研究了Nb含量对热轧盘条显微组织、力学性能和低温冲击韧性的影响.结果表明,两种试验盘条显微组织均为铁素体+少量珠光体,含Nb盘条晶粒细小,且珠光体含量较少;Nb(C、N)在轧制和冷却过程中析出,提高盘条屈服强度和同圈性能稳定性;添加Nb元素明显提高热轧盘条低温冲击韧性.     

Φ430mm圆坯表面质量问题及改善措施

包钢Ф430 mm圆坯经过热轧生产的无缝钢管大批量出现外结疤,通过热酸及裂纹分析发现是因为圆坯表面存在着微裂纹,在随后的热轧生产中形成外结疤,针对Ф430 mm圆坯表面出现微裂纹的问题,通过调整炼钢连铸工艺和钢种成分,制订出相应的改进措施。圆坯表面质量得到明显改善,经过热轧生产后,钢管成材率得到提高。     

采用控温轧制根除油管表面结疤的研究

对７３×５．５１油管表面结疤、性能不稳定等问题进行了分析、研究，提出了控温轧制的最佳工艺方案，从而减少直至根除了终轧温度对性能的不良影响。     

转炉炉壳热应力分析

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。     

Results of treatment of cancer of the cardia

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.     

焦炭热性能指标意义浅析

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。     

Effect of antibiotics of chemotaxis of human leukocytes

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.     

Quality of life of relatives of mental patients

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.