含钛焊丝钢小方坯连铸水口的结瘤机制

 利用扫描电镜对含钛焊丝钢中夹杂物性质及连铸水口结瘤物的物相组成进行了分析,并结合热力学计算研究了水口结瘤的形成机制。结果表明,LF 精炼出站钢液中存在大量Al2O3、TiO2夹杂物,并不断附着沉积在水口内壁形成氧化铝型、氧化钛型或两者结合的结瘤物,连浇炉数仅为4次。通过优化钢中［Al］-［Ti］-［O］关系,控制铝质量分数在钛-铝竞争氧化平衡线之上,即w(［Ti］)/w(［Al］)4/3>84.49 且w(［Ti］)/w(［Al］)>7.46,当钢液中w(［Al］)<0.0068%时,能够降低Al2O3夹杂比例,有效减轻水口结瘤,连浇炉数提升至6炉次。     

含钛不锈钢连铸水口结瘤和结晶器"结鱼"

总结了前人在含钛不锈钢方面的研究工作和工业实践进展.指出合钛不锈钢结晶器"结鱼"主要是由于钢中氮钛浓度积偏高,导致TiN夹杂物大量析出,并在结晶器弯月面聚集,与保护渣反应放出氮气,致使局部钢液温度下降凝固后形成的;TiN型水口结瘤主要由于浇铸过程中TiN夹杂物附着在浸入式水口内壁造成的;TiO2型水口结瘤主要是二次氧化造成TiO2夹杂物大量增加,并在浇铸过程中附着在连铸水口内壁形成的;CaO·TiO2型水口结瘤主要是钢中Ca＞0.001%,Al＞0.01%的情况下,加入Ti后钢中形成数量较多的CaO·TiO2-MgO·Al2O3双相夹杂物,并在浇铸过程中附着在水口内壁形成的.同时阐述了上述连铸水口结瘤和结晶器"结鱼"的控制措施和工业实践中取得的进展.     

含钛不锈钢连铸浸入式水口结瘤的研究

为了解决含钛不锈钢连铸过程中浸入式水口的结瘤问题,采用扫描电镜和 X射线微区衍射等方法分析了AISI 321不锈钢连铸水口结瘤物的物相,探讨了浸入式水口的结瘤机理。结果表明:水口结瘤物中的物相主要有CaO·TiO2 -MgO·Al2O3 和金属,其中CaO·TiO2- MgO·Al2O3 主要来自于钢液中的夹杂物。喂钛线后吹氩搅拌过强使钢液面裸露和浇铸时的二次氧化会显著增加钢中CaO·TiO2- MgO·Al2O3 双相夹杂物的数量,导致结瘤层明显变厚。冶炼过程中采用低铝硅铁(ωAl=0 05%)还原,且不加铝、Ca- Si脱氧,或者在加 Ca Si后通过喂钛线前的吹氩弱搅拌尽可能排除钢中CaO- SiO2、CaO- SiO2 Al2O3 等夹杂物,严格控制二次氧化,可使喂入钛线后钢中CaO·TiO ·Al O 双相夹杂物数量明显减少,从而改善水口结瘤现象。     

高钛焊丝用钢的钢液可浇性改善

 用扫描电镜（SEM/EDS）分析了高钛焊丝钢连铸水口结瘤物和钢液中夹杂物的形貌和组成,结果表明：结瘤物的主要组成是[TiOx]和凝钢;精炼结束后钢液中的夹杂物主要是[MnO-Al2O3-SiO2-TiOx]、[MgO-Al2O3-TiOx]和[TiOx]类夹杂物;钢液中大量的高熔点含钛夹杂物是导致水口结瘤的主要原因。对钢液中的Al-Ti-O平衡和钢渣间的平衡进行了热力学计算,结果表明：当[w([Al])/w([Ti])＜0.15]时,氧优先与钛结合,反之优先与铝结合;当钢包渣中的[w((FeO))][＜]0.05%、[w((SiO2))][＜]15%时,可避免钛被炉渣氧化。通过对冶炼工艺参数和操作过程的优化,钢液中[TiOx]的质量分数从0.002 4%降低到0.001 0%以下,钢液的可浇性得到明显改善。     

板坯连铸水口结瘤机理研究

通过对CAS-OB精炼钢水板坯连铸水口结瘤物的物相分析和钢中夹杂物的类型分析,研究了中间包浸入式水口、钢包下水口滑板处结瘤的机理,发现浸入式水口结瘤物是CaO·Al2O3和CaS;钢包下水口和滑板处结瘤物主要是CaO-2Al2O3;通过同炉钢中夹杂物检验,证明结瘤是钢水中相同类型的夹杂物沉积粘附在水口内壁造成的.讨论了m(Ca)/m(Al)和钢中S、Al含量对水口结瘤的影响,为了防止水口结瘤,钢中的S、Al含量应控制在12CaO·7Al2O3生成曲线的下方,并保持m(Ca)/m(Al)》0.13.     

含钛焊丝ER70S-G可浇性研究

通过对ER70S-G冶炼过程中上水口及浸入式水口结瘤物的分析发现:上水口的结瘤物以Ti_2O_3、Al_2O_3-Ti_2O_3、Al_2O_3-Mg O-Ti_2O_3为主,浸入式水口的结瘤物以Ti N为主。通过控制钢液中氧含量至10×10~(-6)以下,控制w([Ti])/w([Al])至17~22,可以有效降低上水口结瘤中Ti_2O_3含量至10.2%~10.6%,缓解上水口结瘤现象。通过降低钢液中氮含量至(30~40)×10~(-6)范围,同时控制中包过热度至40℃~55℃范围内(ER70S-G液相线温度1 518℃),可以有效阻止Ti N的析出,从而解决浸入式水口结瘤问题。     

连铸含钛不锈钢浸入式水口结瘤的形成机理

为了搞清连铸含钛不锈钢时浸入式水口CaO.TiO2型结瘤的机理,在实验室碳管炉中进行了铝碳质耐材棒浸入321不锈钢钢液的实验。结果表明,结瘤是由于钢中CaO.TiO2等夹杂物沉淀附着在耐材棒表面形成的。如果存在二次氧化,钢中夹杂物数量明显增加,相应形成的结瘤层也较厚。提高钢液温度50℃对钢中生成的氧化物夹杂的类型没有影响,但是,能显著减少结瘤层中的凝固金属,使结瘤层减薄。     

含钛焊丝钢铝钛氧化物夹杂形成的热力学分析及应用

采用热力学方法对含钛合金焊丝钢中氧化铝和氧化钛夹杂物的形成进行了理论计算.利用扫描电镜对钢中夹杂物的性质进行了分析.结果表明:TiO2-Al2O3和Ti2O3-Al2O3竞争氧化反应的临界条件分别为[％Ti]/[％Al]4/3=84.49和[％Ti]/[％Al]=7.46;当[％Ti]/[％Al]4/3＜ 84.49和[％Ti]/[％Al]＜7.46时,钢中优先生成Al2O3,反之生成Ti2O3或TiO2.当钢中w(Alt)由0.036 0％降至0.004 6％,钢中夹杂由Al2O3向Al2O3·TiOx、TiOx型转变,与理论计算相符.通过控制钢中w(Alt)＜0.005 0％和软吹工艺参数,可有效减少Al2O3夹杂数量,连浇炉数提高至6炉.     

ASP工艺生产Ti-IF钢水口堵塞原因分析及改进

利用光学显微镜、扫描电镜及能谱分析对超低碳Ti-IF钢ASP连铸过程浸入式水口结瘤物取样分析表明,结瘤物中铁和夹杂物交互存在,夹杂物包括二铝酸钙、Al2O3、ZrO2和RO相等。水口堵塞主要是由于钢液中高熔点脱氧产物Al2O3和钙铝酸盐沉积粘附在水口内壁结瘤造成,Ti使水口结瘤现象严重。通过将RH单联法优化为LF+RH双联法,优化钙处理效果并控制过剩[Ti]0.02%,改善了钢水可浇性,实现了8炉以上连续浇铸。     

超低碳钢连铸过程中Ti和P对水口结瘤的影响

浇注含Ti超低碳钢时,浸入式水口内产生结瘤,严重影响生产效率,同时对产品质量造成危害。根据企业生产的经验,随着超低碳钢中Ti和P含量的增加,水口结瘤的问题越来越严重。通过深入分析实际生产过程的试样和实验室研究,阐明浇注超低碳钢时Ti和P对水口结瘤的影响。分析了含Ti含P的超低碳钢水口结瘤物的成分,结果表明结瘤物的主要成分是氧化铝(>90%),Ti含量较少(0.58%～3.58%)。采用脉冲分布解析原子发射光谱法(OES-PDA)测得氧化夹杂物的大小随Ti含量的增加而变小。采用液滴法测定了溶质Ti和P对钢液/Al2O3体系的润湿性影响,结果表明Ti和P使体系接触角和钢液表面张力降低,其中Ti能够降低体系的接触角只是在其具有反应湿润性的情况下。研究表明Ti和P对产生结瘤的作用有显著区别:只要形成的表层界面具有润湿性,Ti就可以降低Al2O3夹杂物的大小,而氧化铝夹杂物颗粒越小,越容易结瘤。为了不产生结瘤就必须控制好Al脱氧的时间和Ti的加入时间。P可以增加Fe-Ti-P三元体系的润湿性是因为P可以增加Ti的活度,降低钢液的粘度。与Ti相比,P对产生结瘤的影响较小。     

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。     

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。     

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.     

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.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

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)