CSP热轧低碳钢的强化机制研究

研究了CSP热轧低碳SPHC钢的微观组织、第二相粒子的析出及其对强度的影响,对马钢CSP生产的SPHC钢和常规热轧工艺的SPHC钢进行了屈服强度比较.结果表明,马钢SPHC钢的实测值比计算值高42MPa,常规工艺生产的SPHC钢实测值与计算值比较接近.对马钢SPHC钢进行透射电镜观察,观察到其中存在纳米级的、亚微米级的和微米级的3种尺寸级别的第二相粒子,马钢SPHC钢沉淀强化的强度增量为40 MPa.     

冷却模式对CSP线生产热轧双相钢DP600的影响

针对酒钢CSP线,设计了600 MPa级热轧双相钢的化学成分,测定了其动态CCT曲线。根据动态CCT曲线,分别采用三段式与两段式冷却模式进行了现场试制,对试制热轧板进行了显微组织观察与力学性能检测。结果表明:通过化学成分的合理设计及关键工艺参数的合理控制,热轧板的显微组织为铁素体+马氏体,屈服强度均达到325 MPa以上,抗拉强度均达到600 MPa以上,屈强比为0.53～0.58,伸长率均达到26.9%以上,并且其应力-应变曲线为连续屈服。两段式与三段式冷却模式都可使热轧板的综合性能达到了DP600热轧双相钢的性能指标。虽然两段式冷却模式在工艺上控制简单、更易于实现,但二段式冷却模式得到的屈服强度偏低;采用三段式冷却模式,并将一段快冷结束温度控制在700℃左右,可得到相对较高的屈服强度,使热轧板的综合性能更佳。     

珠钢薄规格热轧钢板生产技术

介绍了2006年珠钢薄规格热轧板的生产情况.通过对薄规格热轧板轧制技术的研究,进而开发了薄规格热轧板生产的成套技术,实现了薄规格热轧板的高比例、高质量、高效化的生产,普通碳素结构钢板厚度≤2.0 mm的比例达到70%以上,≤1.5 mm的比例达到35%以上;集装箱用钢板厚度≤2.0 mm的比例达到70%以上,≤1.6 mm的比例达到40%以上;屈服强度345 MPa级的集装箱用钢板极限厚度为1.4 mm,屈服强度550 MPa级的高强汽车结构钢板极限厚度为1.8 mm,屈服强度700 MPa级的超高强耐候钢板极限厚度为2.0 mm.     

武钢CSP低碳冷轧基料铁素体轧制工艺开发与实践

对CSP铁素体轧制、CSP奥氏体轧制和常规奥氏体轧制3种工艺生产SPHC钢卷的组织与性能进行了对比分析。结果表明,在相同化学成分下,CSP铁素体轧制钢卷屈服强度、抗拉强度和屈强比比奥氏体轧制钢卷均有较大幅降低,铁素体晶粒由10级降低为6~7级;CSP铁素体轧制钢卷与另2种工艺相比,可大幅降低冷轧机组的轧制力和轧制电流,减少轧机能耗,同时冷轧退火后性能更优良。     

首钢西气东输二线用X80热轧板卷产品设计和性能分析

介绍了首钢西气东输二线输气管道工程用X80热轧板卷的项目来源、技术背景和产品设计思路。根据西气东输二线用18．4mm X80热轧板卷技术条件,特别是螺旋埋弧焊管30°拉伸性能制管后横向拉伸性能最低、螺旋埋弧焊管制管后无冷扩径的特点,实际X80板卷的强度性能要求达到X100钢级平板的拉伸性能。针对X80板卷的性能要求和试制难度,设计了低碳、高锰、少钼、高铌和微钒的成分体系,并重点分析了钼、铌和钒等微合金元素的强化效果。同时,针对X80板卷制管过程中出现的应变时效现象,分析了其化学成分和工艺参数对热轧板卷性能的影响。     

SPHC冷轧基料质量改进

介绍了SPHC产品的化学成分和力学性能标准,针对SPHC钢带镰刀弯、边部黑线等问题,从工艺优化、改善钢带力学性能方面进行了理论分析,制定实施了相应技术措施.对实物质量进行了检测,产品的屈服强度和抗拉强度分别提高20 MPa和10 MPa,伸长率基本不变,产品质量大幅度提高.     

优化SPHC钢种冷轧基板力学性能的生产实践

针对SPHC钢种冷轧基板屈服强度和屈强比偏高的问题,分析认为是基板晶粒度级别较高所致。通过采取优化加热温度和在炉时间、控制精轧终轧温度、轧后层流冷却采用后段冷却方式等工艺优化措施,屈服强度由310 MPa降至270MPa,屈强比由0.81降至0.77,晶粒度由10.5~11.0级降至8.5~10.0级,钢带性能稳定。     

S275JR厚规格热轧卷表面裂纹成因分析与改进

针对国内某厂在轧制厚规格S275JR钢卷过程中在钢卷中心位置附近出现了大量裂纹缺陷问题,通过对该缺陷宏观形貌、化学成分、金相组织等进行研究分析后,确定了板卷表面裂纹缺陷是由钢坯皮下微裂纹造成的。基于此分析对S275JR生产过程中的硫质量分数、过热度、结晶器冷却强度与保护渣进行了优化。工业实践表明,工艺调整后钢卷表面裂纹缺陷由12%降低到0.93%。     

用CSP热轧卷生产的冷轧退火平整板卷的屈服强度问题

用CSP热轧卷生产冷轧退火平整板卷时遇到的最突出的问题是屈服强度偏高,导致成形性不良.从再结晶规律、退火工艺、平整工艺、酸洗轧制线卷取张力、热轧工艺、化学成分等方面进行了系统研究,解决了CQ、DQ级冷轧退火平整产品材质偏硬,冲压开裂这一质量问题.     

SPHC钢种屈服强度与残余元素相关性分析

为了解决SPHC钢种屈服强度不合格率高的问题,在大量生产数据的基础上,应用SPSS软件Logistic回归模型分析该钢种屈服强度与残余元素之间的相关性后得出结论,屈服强度与钢中Ni、Mo残量具有显著相关关系。进一步应用决策树(CRT)模型分析认为,钢中Ni元素应控制在0.017 95%以下,Mo元素应控制在0.004 95%以下。生产中据此控制Ni和Mo元素含量后,SPHC钢种屈服强度不合格率由12.34%降至平均1.71%。     

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。     

显微维氏硬度测量不确定度评定

对显微维氏硬度测量不确定度进行评定，建立了不确定度计算的数学模型，确定了影响实验结果的各项因素，计算出了各因素的标准不确定度，得出结果的扩展不确定度，并给出最终测量结果的表达式。     

Concept of freedom of infection of animal flocks

Totally negative results of epidemiological investigation of random samples do not prove the absence of the infection as the pathogen may be restricted to only a few animals in the herd for a long time. The statement "absence of infection" is critical for such situations. The question is raised, whether the statement "absence of infection" should be generally avoided. Classification of herds and flocks according to the prevalence of the pathogen would be more valid for the implementation of control measures.     

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。     

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.     

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。