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通过对3种不同铌、钒含量的低碳钢进行多道次热压缩变形以模拟中厚板的超细晶轧制工艺,考察了显微组织演变过程、微合金元素和变形条件对组织演变的影响。结果表明:变形过程中有部分奥氏体通过形变诱导相变转变为铁素体;变形并快速冷却后得到平均晶粒尺寸为3~6μm的超细晶组织.铌促进、钒抑制形变诱导铁素体相变,铌、钒微合金化均有较好的细化作用,铌的作用优于钒.再结晶温度以上进行的粗轧有利于精轧时形变诱导铁素体的形成;在精轧温度范围内,增加变形道次、降低道次应变率有利于获得细化的显微组织;降低终轧变形温度对组织细化是最有效的. 相似文献
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16MnNb中厚钢板控轧工艺的试验研究 总被引:4,自引:0,他引:4
通过热模拟和轧制试验,测定了16MnNb钢再结晶软化率与道次变形量及间隔时间的关系;确定出16MnNb中厚钢板控轧时的精轧温度区间和道次变形量分配原则;所提控轧工艺对含铌Q345钢同类品种板的生产有参考价值. 相似文献
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对含有Ti,Nb,Ti—Nb的三种无间隙原子钢(IF钢),利用多道次扭转试验,研究了它们总的精轧变形量(从2.1~3.2)和精轧开轧温度(从990~930℃)的影响。这些试验的应变速率为2s~-1。在精轧中,静态再结晶是造成早期轧制阶段轧制间隙期间高度软化的原因。在后来的轧制阶段,动态再结晶的出现取决于钢的化学成分、精轧总变形量和精轧温度。lF钢的临界温度是模拟粗轧工艺确定的。以相同的轧制工艺为条件.Nb固定钢晶粒最细,反之,Ti固定钢铁素体晶拉最大。由于精轧的间隙时间(1~2s)比粗轧的间隙时间要短得多,所以精轧时IF钢呈现出高的未再结晶温度。 相似文献
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本文通过研究控制轧制对钢的组织和性能的影响,确定了控制轧制技术对20g钢板的适宜性。研究轧制道次及压下率对变形奥氏体的再结晶和晶粒大小的影响结果表明:热轧奥氏体晶粒是逐道细化的,但前两道轧制细化作用最大,随后道次细化作用逐渐减弱;在以20%的道次压下率轧制时,除第一、四道外,变形奥氏体都发生充分的再结晶,而在以10%的道次压下率轧制时,在所有道次中都只发生部分再结晶,20%的道次压下率要比10%为好。轧制道次及压下率对20g钢板轧后铁素体晶粒尺寸的影响规律表明:奥氏体再结晶区轧制的道次压下率及终轧温度是决定轧后铁素体晶粒大小的主要工艺参数。根据本实验结果拟定了适宜的轧制工艺参数。 相似文献
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《钢铁研究学报》2001,13(3):5
利用热机械模拟器 (Gleeble15 0 0 )模拟了热轧双相不锈钢的控轧过程。研究表明 ,细化的显微组织和机械性能取决于精轧温度 ,即临界区的热处理温度。采用各种方法测量了含铌钢的奥氏体再结晶特性和 γ/ α转变温度。主要研究结果如下 :由于增加了铁素体的形核点和促进 γ/ α转变 ,使铁素体晶粒细化 ,从而降低精轧温度到 80 0℃ ,改善了钢材的强度和延展性。当精轧温度低于 80 0℃时 ,由于铁素体体积分数增加而使强度下降。 V和 Nb元素可阻止奥氏体再结晶 ,扩大非再结晶区域 ,并有利于铁素体晶粒的细化。此外 ,精轧也可以在高温区进行。在… 相似文献
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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
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K Ohta M Nishi M Ueda S Ohyama T Matsubara T Takahashi T Nakajima 《Canadian Metallurgical Quarterly》1998,99(9):589-594
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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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
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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
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TA Solokhina LS Shevchenko IuV Se?ku EG Rytik LV Besedina TS Veshchugina 《Canadian Metallurgical Quarterly》1998,98(6):42-46
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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