55SiCr弹簧钢热轧盘条拉拔断裂原因分析

55SiCr弹簧钢热轧盘条在拉拔过程中发生断裂,为查明断裂原因,采用光学显微镜、扫描电镜和电子探针对试样进行了相关分析。结果表明:盘条芯部马氏体偏析带在拉拔过程中产生的裂纹是断裂起源,这些裂纹沿切应力最大方向扩展,造成了盘条的拉拔断裂。     

汽车悬架系统用55SiCr弹簧钢丝带状组织

 为了研究中心偏析对弹簧钢组织性能的影响,通过金相显微镜、扫描电镜、电子探针等手段研究了55SiCr弹簧钢的元素偏析行为、带状组织及力学性能。结果表明,带状组织由合金元素偏析引起,其内部锰、铬和硅质量分数为非偏析带2倍以上,合金元素偏析引起带状组织,弹簧钢拉伸试样中裂纹起源于偏析带状组织,并沿垂直于带状组织方向扩展导致最终断裂,带状偏析是影响高强度弹簧钢力学性能的主要因素。     

弹簧钢55SiCr拉拔钢丝延迟断裂原因分析

利用金相显微镜、扫描电镜分析了弹簧钢55SiCr拉拔钢丝延迟断裂的原因,发现钢丝表面存在高碳回火马氏体组织形成的硬化层,且存在细小裂纹;断口呈现脆性断裂特征,在表面异常组织区域存在含F的CaO-SiO2-Al2 O3-MgO-MnO-Na2 O大型复合夹杂和C成分夹杂.追溯此批材料的炼钢过程,发现连铸过程的非稳态控制是...     

65号高碳盘条拉拔断裂原因分析

65号高碳盘条在拉拔过程中出现断裂.通过对断裂试样进行金相检验、扫描电镜及能谱分析,探讨了盘条发生断裂的各种原因.结果表明,连铸过程中保护渣的卷入、成分偏析、索氏体化率低、表面缺陷等都可能导致拉拔断裂,并提出了相应的预防措施.     

改善弹簧钢小方坯中心偏析及线材性能工艺优化

针对某钢厂生产的55SiCr弹簧钢,用户加工后的油淬火钢丝断面收缩率在40%以下,影响后续卷簧过程和弹簧的使用寿命,通过低倍酸洗试验,拉伸试验,油淬火调质处理,钻屑试验等方法对铸坯和线材进行评价检测,发现铸坯中心偏析是导致拉拔性能差的主要原因,通过开展连铸工艺优化试验,研究结果表明：高过热度控制对铸坯偏析及线材拉拔性能有显著影响,过热度为35℃相较于过热度18℃,断面收缩率和伸长率分别提高2%和0.8%;结晶器电磁搅拌电流从150 A增加到320 A,中心等轴晶率由8%～8.5%增加到10.5%,但是中心碳平均偏析指数也随之增加;相同结晶器电磁搅拌工艺时,降低凝固末端电磁搅拌强度有利于改善中心偏析;铸坯中心碳平均偏析指数由1.10降低到1.02时,油淬火调质态线材断面收缩率由39%增加到47%。     

82B线材笔尖状断口分析与工艺改进国

对82B在拉拔过程中出现的笔尖状断口进行分析,认为铸坯中心碳、锰、铬成分偏析以及轧后冷却速度过快产生了马氏体组织,相变时引起晶格畸变,由于马氏体硬度高、变形能力差,微裂纹在拉拔过程中萌生并扩展,导致断裂。这是导致笔尖状断裂的主要原因,为此通过采取措施降低铸坯成分偏析,优化轧后冷却工艺,降低马氏体组织尺寸,取得了较好的效果,解决了拉拔过程笔尖状断裂现象。     

82B线材笔尖状断口分析与工艺改进

对82B在拉拔过程中出现的笔尖状断口进行分析,认为铸坯中心碳、锰、铬成分偏析以及轧后冷却速度过快产生了马氏体组织,相变时引起晶格畸变,由于马氏体硬度高、变形能力差,微裂纹在拉拔过程中萌生并扩展,导致断裂。这是导致笔尖状断裂的主要原因,为此通过采取措施降低铸坯成分偏析,优化轧后冷却工艺,降低马氏体组织尺寸,取得了较好的效果,解决了拉拔过程笔尖状断裂现象。     

高品质汽车悬架弹簧钢55 SiCr生产工艺实践

采用KR铁水脱硫—130 t BOF—炉外精炼(LF+RH)—320 mm×425 mm大方坯连铸—开坯—热轧工艺生产汽车悬架弹簧钢55SiCr,通过采取控制入炉铁水成分、转炉终点成分、LF终渣碱度、连铸过程全程无氧保护浇注等工艺措施,生产出低倍组织良好、纯净度高的55SiCr弹簧钢,结果表明:钢水中磷、硫的质量分数小于0.010%,氧的体积分数不大于10×10-6,钢中非金属夹杂物A,B类不大于1.0级,C,D类不大于0.5级,满足了用户对汽车悬架弹簧钢的技术要求.     

65号线材拉拔断裂原因分析

采用金相检验和扫描电镜观察相结合的方法,研究65号钢在拉拔中出现断裂的原因,通过对断裂样品分析,得出引起拉拔断裂是由钢中脆性夹杂物的聚集、成分偏析和铸坯表面缺陷造成的。结合工艺分析,提出改进高碳钢质量的措施。     

汽车悬架弹簧用55 SiCr热轧盘条的研发

介绍了河钢邯钢试制Φ12mm汽车悬架弹簧用55SiCr热轧盘条的研发过程及用户使用情况。通过采用无铝脱氧、窄成分控制、低过热度恒拉速等炼钢工艺;铸坯角部修磨;轧钢重点控制加热温度和加热时间,避免脱碳层超标等一系列技术措施。开发的55SiCr弹簧钢热轧盘条各项性能指标均满足GB/T1222-2016要求。制成汽车悬架弹簧后,疲劳试验达到17万次未发生断裂,满足用户需求。     

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。     

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.     

Comparison of the results of surgical and conservative treatment of fractures of the diaphysis of the tibia

In this paper is treated the fundamental problematic of the fracture of the diaphysis of the tibia and the therapeutic results after the conservative and operative treatment are confronted. Among 518 patients with 433 open fractures and 35 with closed fractures of the diaphysis of the tibia, successful treatment of more 2/3 was obtained in the period from 1968 to 1972. Following our casuistics and literature, whose results are similar, we find out that the average total treatment of the osteosynthesis of the fracture of the diaphysis was shortened for 2,5 months depending upon the type and the localisation of the fracture. Apolied methods of the operative and conservative and conservative treatment in relation to the velocity of the medical cure as well as to the extreme anatomical-functional results are analised. We noticed that osteosynthesis, made by the intermedullary nail and the extension of the canals or by a small AO table, by the achieved stability makes conditions of immediate motions and an early rehabilitation. Because of that it gives the best functional results.