双相不锈钢S22053的焊接工艺性能的研究

奥氏体-铁素体双相不锈钢简称双相不锈钢,具有优良的力学性能和耐腐蚀性能,S22053双相不锈钢在石油及天然气工业,化学工业等行业具有广泛的应用。材料特性第二代双相不锈钢一般称为标准双相不锈钢,成分特点是超低碳、含氮,其典型成分为22%Cr+5%Ni+3%Mo+0.17%N(见表1,机械性能见表2)。与第一代双相不锈钢相比,S22053进一步提高氮含量,增强在氯离子浓度较高的酸性介质中的耐应力腐蚀和抗点蚀性能。氮是强烈的奥氏体形成元素,加入到双相不锈     

热等静压UNS S32750超级双相不锈钢的组织和性能

采用等离子旋转电极雾化-热等静压工艺制备了UNS S32750超级双相不锈钢。利用光学显微镜、扫描电子显微镜、电子背散射衍射、万能试验机等手段研究了热等静压UNS S32750超级双相不锈钢固溶处理前后的显微组织和力学性能。结果表明:采用等离子旋转电极雾化制备的UNS S32750超级双相不锈钢粉末在150 MPa 压力下,经1200 ℃×3 h热等静压烧结后实现了致密化,相对密度为99.7%。随炉缓冷过程中,烧结件中析出的σ相导致材料韧性显著下降。经1035 ℃×1 h固溶处理后水淬,σ相完全溶解,材料韧性显著提高,显微组织为α和γ两相组织,体积比为65:35,抗拉强度791 MPa,屈服强度586 MPa,断后伸长率38%,冲击吸收功236 J。     

UNS S32205双相不锈钢焊接工艺研究

针对UNS S32205双相不锈钢焊接工艺进行研究,并对试验结果进行分析。分析表明:UNS S32205双相不锈钢因其铁素体、奥氏体的双相组织结构而具有优良的耐蚀及机械性能,选用2209为填充材料并选择合理的焊接和焊后热处理工艺,可使焊缝区获得良好的双相组织,从而得到耐点腐蚀和冲击性能良好的接头。     

时效条件下2205双相不锈钢中的析出相分析及其对冲击性能的影响

研究采用光学显微镜(OM)、扫描电镜(SEM)、能谱分析(EDS)和透射电镜(TEM)等试验技术,分别对2205双相不锈钢在700、750℃时效处理0.5、12、h后组织中的析出相进行分析。结果表明:在700℃时效处理的条件下,2205双相不锈钢的析出相主要是Cr2N和χ相;750℃时效处理的条件下,析出相主要由Cr2N、χ相以及σ相组成。结合室温冲击功的测量结果,随着时效时间的延长,该钢的冲击功明显降低;在相同时效时间条件下,与700℃时效处理相比,经750℃时效处理后的2205双相不锈钢冲击功较低,这主要是由于组织中σ相的析出造成的。     

稀土22Cr型双相不锈钢组织及力学性能研究

为了研究双相不锈钢热加工过程中稀土对有害析出相的影响,采用扫描电镜(SEM)、X射线能谱仪(EDS)、金相显微镜、X射线衍射(XRD)及冲击性能等测试方法研究了混合稀土La、Ce元素对2205双相不锈钢组织和冲击性能的影响。结果表明,稀土元素细化了22Cr型双相不锈钢的显微组织,并且富集在相界及其周围,减小了铁素体/奥氏体界面处Cr、Mo元素的富集程度,延缓了σ相的析出;混合稀土通过细化晶粒、变质夹杂物和延缓σ相的析出提高了22Cr型双相不锈钢的冲击韧性,20℃时提高约40%,促使其断裂机制从解理断裂向韧窝断裂转变。     

双相不锈钢高温微观变形行为

 利用共聚焦激光扫描高温显微镜(CSLM)等设备对双相不锈钢的高温拉伸变形行为进行了研究,分析了双相不锈钢的热塑性变形机理,得出影响双相不锈钢热塑性的主要因素有：相界结合力、组织形貌和两相力学性能的差异。指出在双相不锈钢热加工时,增强相界结合力、优化组织形貌或减小两相力学性能差异,可有效改善双相不锈钢的热塑性。     

铈对S32550双相不锈钢微观组织及冲击性能的影响

 双相不锈钢兼具奥氏体和铁素体不锈钢的优良性能,多用于船舶、化工、核反应等领域。为了进一步提高S32550双相不锈钢的力学性能和抗腐蚀性能,采用真空感应炉成功冶炼了S32550双相不锈钢,并研究了有无添加稀土铈对其锻造、轧制后的微观组织、夹杂物形貌及冲击性能的影响。结果表明,添加稀土铈可以细化组织晶粒,使形状分布不均匀的铁素体组织与奥氏体组织均匀化;改善夹杂物形貌分布大小,对有害夹杂MnS进行改质,降低硫含量,使多余硫元素与铈反应形成Ce₂O₂S、Ce₂S₂夹杂弥散分布在钢中;另外,添加稀土铈可以提高S32550双相不锈钢在室温和低温(-40、-20 ℃)下的冲击韧性,在低温下可出现韧窝带,降低冷脆效应对钢材的危害。     

经济型双相不锈钢的研发进展

 经济型双相不锈钢是一种高性能低成本的氮合金化不锈钢新材料,具有典型的铁素体-奥氏体双相组织。利用氮取代镍元素的奥氏体化作用,降低成本的同时获得优良的力学性能和耐腐蚀性能。介绍了经济型双相不锈钢的发展历史,重点讨论了合金元素和热处理对相变、力学性能和耐腐蚀性能的影响规律,并与304和316进行对比;同时,分析了经济型双相不锈钢焊接性能和焊接工艺的研究进展。经济型双相不锈钢S32101、S32003、S32202等,已用于核电、桥梁、建筑、热交换器等行业,取代传统奥氏体不锈钢AISI 304和316。由于经济型双相不锈钢具有高强度和优良耐蚀性,同时镍、钼等贵金属的含量都较低,已成为未来不锈钢发展的方向之一。     

时效温度对S32101双相不锈钢组织和力学性能的影响

利用光学显微镜、铁素体仪进行了硬度和拉伸实验,研究了S32101双相不锈钢不同时效态下组织与力学性能之间的关系。研究结果表明,随着时效温度的升高,S32101双相不锈钢的屈服强度、抗拉强度和硬度减小,延伸率增大;析出相的产生是造成力学性能变化的主要原因,700℃为最敏感析出温度,900℃时析出相开始逐渐消失。     

节约型双相不锈钢组织演变规律的研究进展

节约型双相不锈钢是一种高性能、低成本的结构材料,拥有广阔的应用前景,有望广泛应用于核电、石化、造船、造纸和海水淡化等领域,但是其热加工制备困难,阻碍了大规模工业化生产。简要介绍了国内外双相不锈钢的研究现状,综述了双相不锈钢的组织性能演变、热变形规律及脆性相析出行为等。从组织演变规律入手,指出改善节约型双相不锈钢热塑性的重要性及可行性。     

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)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

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.