超高强度冷轧双相钢组织与性能

在Gleeble-3500热模拟试验机上进行冷轧超高强度双相钢的连续退火工艺研究,利用光学显微镜、扫描电镜、透射电镜和拉伸试验研究了连续退火过程中各个参数对1000MPa级冷轧双相钢组织性能的影响.结果表明:试验用钢在退火温度800℃下保温80s,可以得到抗拉强度为1030MPa、延伸率为14%超高强双相钢;随着退火温度的升高,屈服强度和抗拉强度降低.当退火温度为830℃时,显微组织中粒状的非马氏体组织明显增多.过时效温度低于300℃时,屈服强度和抗拉强度变化不大;当过时效温度超过300℃时,抗拉强度急剧下降,屈服强度先降低后升高,在过时效温度为360℃时开始出现屈服平台.     

连续退火工艺对冷轧马氏体钢板力学性能的影响

 冷轧马氏体钢采用水淬退火机组生产,可以节约合金元素,同时获得高强度,符合汽车用钢高强度和减重节能的要求。以冷轧低碳马氏体钢为研究对象,研究了连续退火工艺对马氏体钢板力学性能的影响,发现淬火温度、缓冷速度和回火温度均对马氏体钢的强度有很大影响。在奥氏体缓慢分解的较高温度区间开始淬火有利于马氏体钢强度的稳定。回火降低马氏体钢的抗拉强度,对屈服强度有提高的作用,在200~300℃之间回火,冷弯性能基本不变或有所提高,未发现在240℃以上过时效出现显著的冷弯性能下降的现象。     

连续退火时效温度对Si-A1复合TRIP钢组织性能影响的研究

通过模拟连续退火试验,研究了时效温度对某Si-A1添加的590 MPa级TRIP钢力学性能与显微组织的影响.研究结果表明:420℃过时效处理,试验钢获得适量的贝氏体与残余奥氏体,性能表现出良好的强度与延性配合;过时效温度小于420℃,随温度降低,试验钢出现马氏体,性能表现为低屈服、高抗拉,但是延伸率降低;过时效温度高于420℃,随温度的升高,试验钢贝氏体量增加使得屈服和抗拉强度都增加,延伸率降低.     

热处理工艺对塑料模具钢10Ni2Cr2MnCuMoVAl组织和性能的影响

研究了固溶温度、时效温度及时间对10Ni2Cr2MnCuMoVAl塑料模具钢热处理后的微观组织和力学性能的影响。结果表明:固溶处理后,10Ni2Cr2MnCuMoVAl钢的组织主要是板条马氏体构成,且随固溶温度的升高,马氏体板条发生明显宽化,并在890℃固溶后达到硬度最高值。时效处理后的组织由板条马氏体、粒状贝氏体和析出碳化物构成。当时效温度区间为460~520℃,随着时效温度的升高,材料的强度逐渐升高,韧性逐渐降低,并在520℃达到强度峰值;时效温度高于520℃时,随着温度升高,材料硬度降低,冲击韧性升高。分析在540℃不同时效时间处理后的性能可知,试验钢在8h达到力学性能峰值。通过比较试验钢在不同时效处理后的力学性能数据,10Ni2Cr2MnCuMoVAl钢的最佳热处理工艺为:880℃固溶处理2h+空冷,随后在520℃时效处理4h+空冷。     

连续退火时效温度对Si-Al复合TRIP钢组织性能影响的研究

通过模拟连续退火试验,研究了时效温度对某Si-Al添加的590 MPa级TRIP钢力学性能与显微组织的影响。研究结果表明：420℃过时效处理,试验钢获得适量的贝氏体与残余奥氏体,性能表现出良好的强度与延性配合;过时效温度小于420℃,随温度降低,试验钢出现马氏体,性能表现为低屈服、高抗拉,但是延伸率降低;过时效温度高于420℃,随温度的升高,试验钢贝氏体量增加使得屈服和抗拉强度都增加,延伸率降低。     

连续退火过时效温度对热处理双相钢组织性能的影响

 采用光亮连续退火模拟实验机研究了0.08C 1.7Mn 0.03Si钢在不同连续退火过时效温度下组织和性能的变化规律,并构造了各相在连续退火工艺期间的反应关系式。试验结果表明：过时效温度在450 ℃时,组织中的第二相主要为粒状贝氏体＋马氏体,350 ℃时为板条状贝氏体＋马氏体,250 ℃时为马氏体或M A岛;过时效温度降低,试验钢抗拉强度明显升高,屈服强度明显降低,而n值、值和杯突值变化不大;350 ℃过时效时,试验钢的伸长率有增高的趋势,因此调整第二相组分比例可能是提高试验钢塑性的有效手段。     

退火工艺对Nb-V微合金化双相钢组织性能的影响

为了进一步提升双相钢性能、探究Nb-V元素复合添加对双相钢组织性能的影响,在实验室研发了Nb-V微合金化的冷轧双相钢。利用连退模拟试验机、扫描电镜等设备,系统地研究了退火温度和过时效温度对双相钢组织性能的影响。结果表明,抗拉强度和伸长率随着退火温度的升高变化不大,屈服强度在组织中铁素体含量明显减少后有显著提升;Nb、V元素的添加细化了组织,可以提高综合性能。随着过时效温度的升高,试验钢主要组织由起初低温时的淬火马氏体+回火马氏体变为高温时的粒状贝氏体,残余奥氏体比例也逐渐增大。高温过时效时,试验钢强度的降低主要由回火马氏体的软化造成;低温过时效时,V析出量的增加也对试验钢的强化起到了重要作用。     

退火工艺对Nb-V微合金化双相钢组织性能的影响

为了进一步提升双相钢性能、探究Nb-V元素复合添加对双相钢组织性能的影响,在实验室研发了Nb-V微合金化的冷轧双相钢。利用连退模拟试验机、扫描电镜等设备,系统地研究了退火温度和过时效温度对双相钢组织性能的影响。结果表明,抗拉强度和伸长率随着退火温度的升高变化不大,屈服强度在组织中铁素体含量明显减少后有显著提升;Nb、V元素的添加细化了组织,可以提高综合性能。随着过时效温度的升高,试验钢主要组织由起初低温时的淬火马氏体+回火马氏体变为高温时的粒状贝氏体,残余奥氏体比例也逐渐增大。高温过时效时,试验钢强度的降低主要由回火马氏体的软化造成;低温过时效时,V析出量的增加也对试验钢的强化起到了重要作用。     

连续退火工艺对双相钢金相组织和力学性能的影响

利用河北钢铁技术研究总院连续退火热模拟机研究了退火工艺对双相钢金相组织与力学性能的影响。结果表明,两相区加热温度升高,试样中铁素体含量下降,晶粒细化,马氏体含量升高,屈服强度增加,抗拉强度变化不大,在820～840℃退火时伸长率达到最大值;两相区保温时间增加,组织中铁素体再结晶充分,晶粒长大,马氏体晶粒并无明显变化,室温时双相钢屈服强度与抗拉强度降低,伸长率明显增加;随着时效温度升高,屈服强度缓慢增加,抗拉强度缓慢减小,在时效温度230～270℃时,伸长率随时效温度升高而降低,并在290℃时取得最大值。     

低碳铁素体加马氏体双相钢的时效行为

本文研究了双相0.08C-1.45Mn-0.21Si钢在时效过程中,铁素体的时效反应及其对拉伸性能的影响。时效温度取室温至170℃,时效时间长短视时效温度高低而异。试验结果表明,时效导致铁素体中有大量细小碳化物析出。铁素体的时效反应有一定的不均匀性,碳化物多在铁素体区域内部析出,而在马氏体附近析出较少。在较高温度(70℃以上)时效时,可使不连续屈服重现,并且随着时效时间增加使小变形阶段应变硬化率降低,有利于塑性提高。钢的屈服强度因时效而增加,抗拉强度先增后减。文中针对铁素体的时效反应与拉仲性能的关系进行了相应的讨论。     

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.