厚规格高强度钢Q690D的淬透性研究

通过端淬试验、硬度测试和显微组织分析,研究了2种成分不同厚度Q690D的淬透性。结果表明:1#50 mm厚Q690D淬火态边部和厚度1/2处硬度HRC差值为12,淬透性较差;通过调整成分和热处理工艺极大地改善了厚规格Q690D的淬透性,2#50~70 mm厚Q690D淬火、回火态边部和厚度1/2处硬度差值较小,50 mm厚两者硬度HRC差值最大也只有为5。     

调质工艺对Q690D钢综合力学性能及组织的影响

 以60mm厚Q690D高强度结构钢板为研究对象,在相同轧制条件下,系统地研究了淬火、回火温度对试验钢综合力学性能及显微组织的影响,并对第二相析出进行理论分析。试验结果表明：随淬火温度升高,试验钢强度升高,韧性下降;随回火温度升高,试验钢强度下降,但韧性明显升高。该钢采用930℃淬火(保温10min)650℃回火(保温40min)的调质热处理工艺具有良好的强韧性匹配,综合力学性能最佳,满足国标GB/T 16270—2009要求。     

热处理工艺对F550海洋平台用钢组织与性能的影响

通过对不同淬火、回火工艺处理后的F550海洋平台用钢的力学性能、断口形貌、微观组织等进行分析,探讨了淬火、回火工艺参数对钢板性能及组织的影响。结果表明,淬火温度越高,组织晶粒越细小;随回火温度的升高,组织粗化,位错密度减少,钢板强度降低,塑性和韧性提高。16mm厚F550钢板最佳调质工艺为:880℃×120min淬火,630℃×220min回火。调质处理后钢板组织为粒状贝氏体+少量板条铁素体,屈服强度580MPa,抗拉强度660MPa,断后伸长率23%,-60℃冲击功稳定在210J以上。     

硼对60 mm厚Q690D钢淬透性和力学性能的影响

 通过端淬试验、[Z]向硬度测试、显微组织和力学性能分析,研究了硼对60 mm厚Q690D钢淬透性和力学性能的影响。试验结果表明：微量固溶硼可显著提高60 mm厚Q690D钢的淬透性;和无硼的试验钢相比,含硼试验钢板厚1/4处的淬火组织由马/贝复相变成板条马氏体,淬火、回火态横截面上[Z]向最大硬度差分别由9、 5HRC降低到4、3HRC,提高了[Z]向硬度的均匀性,同时含硼试验钢淬火、回火态的强度和韧性得到提高。     

热处理工艺对风电锻件用Q345E钢组织及性能的影响

采用拉伸、冲击与微观组织分析等试验研究了风电锻件用Q345E钢经不同热处理工艺下的组织与性能,试验结果表明:890℃淬火时,随着回火温度的升高,Q345E钢的强度逐渐下降,塑性和韧性逐渐增加;550℃回火时,当淬火温度890℃时,Q345E钢综合力学性能最好;Q345E钢的最佳热处理工艺为890℃淬火+550℃回火。在后续生产实验中,经过890℃淬火+550℃回火后,Q345E钢的力学性能均满足要求,屈服强度大于395MPa、抗拉强度大于530MPa,-40℃冲击功大于185J。     

回火温度对Q690D低碳贝氏体钢组织性能的影响

低碳贝氏体钢因强度高、韧性好，被广泛应用，Q690D是其中的高强度焊接结构钢。针对Q690D原生产工艺复杂、成本高、交货周期长、成品力学性能差等问题，通过金相显微镜和力学性能测试，研究了回火温度对Q690D低碳贝氏体钢显微组织和力学性能的影响。结果表明：试验钢在450～550℃温度回火后，综合力学性能最佳，抗拉强度为817～838 MPa,屈服强度为718～722 MPa,屈强比≤0.86,伸长率为18.5%～20%,-20℃冲击吸收能量达到216～249 J,完全满足国标对Q690D的性能要求，此时试验钢显微组织以板条贝氏体为主，存在少量粒状贝氏体及残余奥氏体。随着回火温度的升高，试验钢中板条贝氏体发生分解，析出物逐渐增多，铁素体再结晶并长大；宏观上表现为试验钢的抗拉强度下降，伸长率逐渐升高，钢板的屈服强度先升高后降低。     

热处理对60Si2CrVAT弹簧钢组织和力学性能的影响

试验了890～930℃淬火、400～440℃回火时淬-回火温度对160mm×160mm连铸坯轧成的Φ21mm 60Si2CrVAT弹簧钢组织和力学性能的影响。结果表明,910℃淬火.回火后的60Si2CrVAT钢抗拉强度高于890℃和930℃淬火-回火钢的抗拉强度,不同淬火温度下钢的抗拉强度随回火温度升高而降低。分析了拉伸断口的组织形貌。     

实验室模拟控制轧制和调质处理对桥梁钢Q690q组织和性能的影响

研究了920℃精轧,830℃终轧以12℃/s冷至590℃,空冷的TMCP控制轧制工艺和TMCP+940℃淬火-630℃回火两工艺的桥梁钢Q690q(/%:0.05C、0.30Si、1.40Mn、1.10Cu、0.50Cr、0.80Ni、0.07V、0.55Mo,焊接冷裂纹敏感指数P_cm≤0.267)15mm板组织和力学性能。结果表明,TMCP工艺生产的桥梁钢Q690q组织主要由粒状贝氏体和少量铁素体组成,TMCP+调质处理后的组织为多边形铁素体和少量渗碳体,其屈服强度R_p0.2为845～870MPa,抗拉强度Rm895～900MPa,-20℃冲击功153～186J, -40℃为141～155 J。调质处理减小了钢材的M/A岛尺寸和位错密度,使Q690_q钢保持高强度的同时也具有较好的冲击韧性。     

调质处理工艺对微合金化Q960E钢70 mm板组织性能的影响

采用890～920℃淬火和560～600℃回火工艺对Q960E钢70 mm板进行性能测试,并利用金相显微镜(OM)、扫描电镜(SEM)对Q960E钢板显微组织进行分析。结果表明：采用920℃淬火和560℃回火工艺的钢板强韧性匹配最优(UTS 1048 MPa, YS 1005 MPa, el.14%,-40℃KV₂ 52～61 J),钢板全厚度方向性能分布相对均匀,硬度值为27.5～33HRC;组织从表面至心部为回火索氏体和残余奥氏体。     

淬火温度对80mm调质690MPa级低碳贝氏体高强钢板组织性能的影响

通过金相显微镜、扫描电镜、力学性能测试,研究了830～930℃淬火+650 ℃回火对690 MPa高强钢显微组织和力学性能的影响.结果表明:实验钢经两相区830 ℃淬火+650 ℃回火后的组织为板条状铁素体和回火索氏体,其屈服强度较低为679 MPa.淬火温度在完全奥氏体化相区为890～930℃时,随着淬火温度升高,材...     

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.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

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.