AF1410钢电子束焊接接头的腐蚀电化学行为

采用光学显微镜对AF1410电子束焊接接头的组织结构进行了分析,并采用中性盐雾腐蚀失重和电化学测试方法研究了焊缝熔合区和基体耐腐蚀性能及电化学行为.结果表明:电子束焊接后的焊缝位置为粗大回火马氏体和析出碳化物;基体的腐蚀失重较焊缝熔合区低.电化学测试表明,焊缝熔合区的开路电位低于基体,腐蚀电流高于基材,阻抗值也较低,易腐蚀,这是回火马氏体与析出的碳化物间存在电位差而导致的电化学反应,使材料在腐蚀介质中腐蚀失效.     

氩弧焊焊接18Ni马氏体时效钢(250)薄板焊接接头的组织和力学性能研究

采用氩弧焊对3 mm厚的18Ni马氏体不锈钢(250)薄板实施焊接,并针对获得的焊接接头的表观质量、显微组织和力学性能进行了分析研究.结果表明,焊接试样的焊缝宽度约6mm,焊缝组织由等轴晶、柱状晶、树枝晶和逆转变奥氏体构成;熔合区是焊缝区与热影响区的过渡区域,宽度很窄;热影响区主要分为HAZ1(黑色区域Ⅰ)、HAZ2(...     

AF1410钢电子束焊接件在模拟海洋环境中的腐蚀行为

采用中性盐雾试验模拟海洋环境,研究了AF1410钢电子束焊接接头不同位置、不同暴露时间的腐蚀电化学阻抗谱特征,并结合电子束焊接接头组织结构分析评价了焊缝熔合区及母材的耐腐蚀性能及电化学行为.开路电位及阻抗谱研究表明,焊缝熔合区的粗大回火马氏体和析出碳化物易构成腐蚀电池,比基材腐蚀反应阻力小,易引起电化学腐蚀.建立了不同腐蚀阶段的阻抗谱等效电路,并对其进行了拟合.      

焊后热处理对沉淀硬化不锈钢15-7Mo焊接接头组织性能的影响

研究了4种不同的焊后热处理工艺对半奥氏体沉淀硬化不锈钢15-7Mo焊接接头组织性能的影响.结果表明:焊接接头不进行热处理或时效热处理的焊接系数低于0.7,焊接接头进行调整+时效热处理后的焊接系数可达0.9,而对焊接接头进行固溶+调整+时效热处理后焊接系数接近1.接头不进行热处理或者是仅时效热处理时,薄弱区为熔合线靠近母材的区域,组织为奥氏体和少量的铁素体.进行调整+时效热处理或固溶+调整+时效热处理时,熔合线靠近母材侧的组织为板条马氏体、少量的铁素体和沉淀析出相,焊缝的组织为板条马氏体和沉淀析出相,薄弱区消失,焊接系数大幅度提高.     

40CrNiMoA钢同质焊条焊接接头组织和性能研究

分析了焊接电流70A、80A、90A对40CrNiMoA钢焊缝接头组织和力学性能的影响。随着焊接电流的增大,焊缝外观质量较好。随着焊接电流的增大,熔池区温度升高,奥氏体晶粒尺寸增大,导致马氏体组织粗大。焊缝的显微组织为马氏体及少量残余奥氏体。焊缝的硬度远高于母材的硬度,且波动较大。热影响区的硬度从母材向沿焊缝方向逐渐升高。焊接接头纵向应力在焊缝中心为压应力,向外压应力减小。焊接颜色区边界处纵向应力为拉应力,且该点拉应力最大。焊接接头横向应力在焊缝中心为拉应力,向外逐渐增大,焊接颜色区边界处变横向拉应力达到最大。焊接电流和热输入增大,降低了材料的韧性,组织中铁素体增多及焊接残余应力是诱发脆性断裂的原因。焊接电流80A是40CrNiMoA同质焊条平板对接焊接工艺的最佳的焊接电流。     

Ti_2AlNb基合金超音频直流脉冲TIG焊

分别采用20,40,50,60 kHz不同频率的4组超音频直流脉冲TIG焊工艺焊接了厚度为1.5 mm的Ti2AlNb基合金板材。并采用X射线探伤手段对焊缝中的气孔缺陷进行检测,比如气孔的数量、尺寸及分布的位置;对于无缺陷的接头,观察接头的宏观和显微组织,测试接头硬度分布规律和拉伸性能。结果表明:采用脉冲频率为40,50,60 kHz的超音频直流脉冲TIG焊工艺对Ti2AlNb基合金进行焊接时,焊缝中气孔数量明显减少,尺寸减小,分布也由接头的内部变为接近表面的位置,在50,60 kHz的频率下能够得到没有气孔缺陷的焊接接头;接头各区域相组成不同,除B2基体以外,随母材向热影响区(HAZ)和熔合区(FZ)过渡,O相含量逐渐减少;由于相组成的变化,焊接接头的硬度分布规律为热影响区的硬度最高,母材次之,熔合区最低;对于4种不同频率的焊接工艺,采用频率为50 kHz时焊接接头抗拉强度最高,可达到926.20 MPa,加焊丝后可以在一定程度上进一步优化焊接接头的抗拉性能,降低同一焊接工艺下试样的性能分散性。     

TA19钛合金电子束焊接头微观组织与性能研究

采用电子束焊接方法对TA19钛合金进行焊接,分析了电子束焊接头各区域的显微组织类型及形貌,测试了接头的显微硬度、室温拉伸、疲劳裂纹扩展速率及断裂韧性等力学性能,并与TA19钛合金母材进行对比。研究表明,焊缝区为粗大的柱状晶组织并存在大量相互交错分布的针状马氏体相,热影响区内随着离熔合线距离的增加马氏体数量逐渐减少;焊缝区显微硬度最高,比母材区显微硬度高出约HV80,随着向母材区过渡显微硬度逐渐降低;焊接接头室温抗拉强度、屈服强度性能及断面收缩率均与母材基本相当,但延伸率略有下降;焊缝区粗大的柱状晶组织硬度高,脆性大,导致焊缝区对疲劳裂纹扩展的抗裂性要低于母材;母材及焊缝KIC值分别为54.49和52.88 MPa·m^1/2,母材抵抗裂纹扩展断裂的能力略好于焊缝。     

TC4钛合金TIG焊接头组织及缺陷分析

针对20 mm厚钛合金开展了TIG焊接工艺试验,采用两种不同的焊接热输入,从组织、性能及焊接缺陷等方面对接头进行了研究。结果表明:接头焊缝区的马氏体较熔合区及热影响区的马氏体分布更加弥散,热影响区马氏体的数量更少且更为细小;焊缝晶粒尺寸随着焊接热输入的增大而增大,晶粒内部的马氏体尺寸也越大且分布越弥散;焊接速度过快是导致气孔缺陷的主要原因,也是严重降低接头力学性能的重要原因。应严格控制焊接热输入,防止接头晶粒粗大,避免产生异常组织和裂纹等缺陷。     

1Cr18Ni9Ti与1Cr13不锈钢焊接接头组织及电化学性能

用金相法观察和分析了用1Cr18Ni9Ti焊丝进行焊接的1Cr18Ni9Ti奥氏体不锈钢板和1Cr13马氏体不锈钢板焊接接头的组织;通过海水模拟溶液浸泡试验,测量焊接接头极化曲线和交流阻抗曲线,对比分析了焊缝与母材的耐腐蚀性能.结果表明,焊接接头组织为典型的柱状晶凝固组织;焊接接头中,马氏体母材和焊缝区容易受到腐蚀,而奥氏体母材不易受到腐蚀.     

热输入对DP600激光焊组织和力学性能的影响

摘要：为了研究DP600钢的焊接性能,采用5种不同的激光焊接工艺进行焊接试验。结果表明,焊接接头表面成形质量良好,随着热输入的增加,上下熔宽逐渐增大;熔融区均为板条状马氏体组织,当热输入高于33J/mm时热影响区组织为马氏体、铁素体和少量的回火马氏体;当热输入低于33J/mm时,热影响区组织为马氏体和铁素体。在低热输入条件下,回火时间很短,马氏体未发生分解;在高的热输入条件下,回火时间较长,马氏体分解显著,热影响区中出现M3C型碳化物,碳化物形貌以球状和片状为主。从熔融区到母材,显微硬度值逐渐降低;焊接接头静态拉伸失效位置均在母材,拉伸断口为韧性断口,DP600钢激光焊接接头不存在软化现象。     

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.