22MnB5钢溶质分配系数及TiN析出对微观偏析的影响

为了提高凝固过程中溶质微观偏析模型计算的准确性,基于溶质分配系数及夹杂物析出对溶质偏析的重要影响,定量分析了溶质分配系数以及TiN析出对凝固过程溶质元素含量的影响,为微合金高强钢凝固过程研究提供理论参考.针对22MnB5钢建立了耦合TiN析出热力学模型的溶质微观偏析模型,并探究了温度及钢液凝固路径对溶质分配系数的影响规...     

帘线钢中氮含量对TiN析出的影响

 研究了攀钢新钢钒公司生产帘线钢72A过程中钢中氮含量变化对钢中TiN夹杂析出的影响。研究发现,随着钢中氮含量的升高,钢中析出的TiN夹杂数量变多,尺寸变大。热力学研究表明,在帘线钢中TiN一般只能在固相区形成,考虑元素偏析对凝固前沿元素富集的影响,凝固过程中TiN能在固液两相区析出。在帘线钢生产过程中,为了控制钢中TiN的析出,除了控制钛含量,控制钢中氮含量及氮偏析更加重要。理论计算结果表明,当钢中钛的质量分数控制在0.0003%~0.0005%区间时,将钢中氮的质量分数控制在0.0017%~0.0029%区间内能显著降低乃至杜绝帘线钢中TiN的析出。攀钢将帘线钢中钛、氮的质量分数分别控制在0.0005%以下和0.002%以下,显著减少了钢中TiN的析出,个别炉次中没有发现尺寸大于2μm的TiN夹杂。     

硼铬微合金钢的脆性断裂失效分析

为了研究硼铬微合金钢的脆性断裂失效机理,以工厂履带拖拉机支重轮的中心轴脆性断裂为研究背景,通过对中心轴断口的观察以及不同位置的组织和晶粒度的对比,得出了硼铬微合金钢的断裂失效机理。利用FactSage和Thermo- Calc软件对TiN夹杂物的析出机理和控制进行理论计算。结果表明,钛合金的不完全溶解和钛、氮元素质量分数的不合理控制,导致大量的大尺寸硬质TiN夹杂物在凝固过程中析出,使得钛元素的加入没有起到很好地细化晶粒的效果,中心区域的铁素体＋奥氏体组织的晶粒度过于粗大。大尺寸TiN夹杂物作为裂纹源和心部粗大的晶粒导致了硼铬微合金钢的脆性断裂失效。热力学计算表明,TiN夹杂物在凝固过程中形成,低钛低氮和钛、氮质量分数的合理搭配可以有效推迟TiN夹杂物的析出,降低其尺寸。较小的夹杂物尺寸和细小的晶粒均可以有效增强材料抵抗裂纹扩展的能力。     

09CuPTiRE钢凝固过程中稀土与钛的相互作用

以09CuPTiRE钢为研究对象,建立钢液凝固过程中溶质偏析和夹杂物析出的耦合热力学模型.利用该模型,研究分析了09CuPTiRE钢凝固过程中稀土与钛的相互作用,得到以下结论:稀土能抑制09CuPTiRE钢中Ti3O5夹杂的析出,当RE含量为0.0045％时,Ti3O5夹杂完全消失;微量稀土有利于09CuPTiRE钢中TiN的析出,随着稀土加入量的增加,对TiN的析出起到抑制作用;钛能抑制09CuPTiRE钢中REN的析出,从而影响凝固过程中RES的析出行为.     

氮对低碳微合金非调质钢组织和性能的影响

通过热力学计算和试验,研究了对Nb-V-Ti-N系低碳微合金非调质钢增氮,以及在液态和凝固过程中TiN夹杂物的析出规律,并且根据氮微合金化原理,确定了低碳微合金非调质钢中最佳的钛含量和氮含量的浓度范围。研究证明,通过调整钢中的氮含量,可以控制TiN夹杂物质量分数和尺寸,从而得到细小弥散的TiN作为针状铁素体的形核中心,细化钢的组织,增强钢的强度和韧性。     

微钛处理对钒微合金钢组织与力学性能的影响

在承钢1780热连轧生产线上,轧制了钒微合金钢及钒钛复合微合金化钢,研究了微钛处理对钒微合金化钢微观组织与力学性能的影响.试验结果表明,钒微合金钢经微钛处理后生成了少量TiN析出物,其数量较少,晶粒细化效果有限;由于钛与氮的优先结合,减少了与钒结合的氮含量,降低了钒的析出量,导致微钛处理的钒微合金钢抗拉强度降低约54 ...     

钛微合金钢中碳氮化钛固溶量及化学组成的计算与分析

根据相关热力学理论,提出了钛微合金钢中钛、碳、氮元素在奥氏体中的平衡固溶量及平衡沉淀析出的碳氮化钛的化学式系数的理论计算方法,对典型化学成分的钛微合金钢进行了理论计算并对计算结果进行了分析.结果表明,通常情况下在较高温度析出或未溶的碳氮化钛相当接近于TiN.     

Nb-Ti微合金钢中第二相析出的热力学计算

分析了Nb-Ti微合金钢在液相、凝固过程、奥氏体以及铁素体相中氮化物、碳化物和碳氮化物等第二相析出的热力学条件,计算了钛和铌的碳化物和氮化物在不同温度下的溶度积,由此得出微合金钢在不同相阶段的析出规律。计算结果表明,在该微合金钢中,氮化物、碳化物和碳氮化物不可能在液相中析出;TiC0.03N0.97和TiN在凝固过程中具备析出的热力学条件;在奥氏体相中,随着温度的降低,氮化物、碳化物及碳氮化物的析出顺序为:NbC0.75N0.25、NbC、TiC、NbN。     

碳含量对帘线钢凝固析出TiN夹杂的影响

对含碳量(质量分数)分别为0.72%、0.82%和0.95%的帘线钢凝固析出TiN夹杂进行热力学研究,结果表明:碳含量对于不同强度级别的帘线钢中TiN夹杂的析出有着明显的影响.随着帘线钢碳含量增加,凝固前沿温度逐渐降低,析出TiN夹杂所需的氮钛活度积也逐渐下降.在相同的钢液初始Ti、N含量条件下,较高碳含量的帘线钢中析出的TiN夹杂尺寸会大于较低碳含量帘线钢中析出的TiN夹杂尺寸.为了控制超高强度级别的过共析帘线钢中TiN夹杂的析出对帘线钢加工性能的有害影响,必须通过冶炼工艺进一步降低钢液中的钛、氮含量.     

连铸中TiN枝晶间的析出

<正>溶质在枝晶间的微观偏析而导致在奥氏体晶界的析出,Ti和N在凝固过程中的微观偏析也会导致TiN在枝晶间的液体中析出。1 500℃时TiN在低合金钢液中的溶度积为6.15×10-4,这是按低合金钢的平均液相线温度所得。当钢液凝固了99%时,有55%的氮转变成了TiN析出物。当钢液完全凝固时%Ti/%N≥3.42,     

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.     

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)     

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.