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1.
为方便研究特殊钢大棒材的现场生产条件、轧制工艺参数对其在轧制过程中变形、温度、轧制力矩的影响,采用C语言编写源程序、MFC模块编写人机交互界面,开发了特殊钢大棒材连轧规程系统。通过本系统对20CrMnTi齿轮钢大棒材的实际轧制工艺参数进行计算,计算值与实测值进行比较,得出计算值与实测值吻合较好。验证了该系统可以较准确预测轧件在轧制过程中温度、轧制力、轧制力矩和能耗的变化情况,为研究特殊钢大棒材的生产工艺以及质量和组织的控制提供可靠的工艺参数。  相似文献   

2.
棒线材轧制的尺寸精度至关重要,但因轧制道次多、孔型内变形复杂,所以提高尺寸精度难度大。建立棒线材连轧过程全部道次轧件尺寸预测通用模型,为计算和预测棒线材轧制变形提供了高效的方法。分别预测了轧制?9 mm规格Q235和65Mn线材以及轧制?40 mm规格40Cr和20CrMnTi棒材全部道次的轧件尺寸,其中轧制参数按照模型推荐的全部道次压下量进行预测,最终预测成品尺寸的相对误差为-1.56%~0.78%,绝对误差为-0.14~0.07 mm,预测精度满足目前钢铁企业实际生产的最高精度需求。该模型在计算不同类型生产线轧制的各类钢种时具有通用性,有较高的计算时效性,可作为棒线材轧制工艺数字化转型的基础模型。  相似文献   

3.
板带热连轧过程力能参数、温度和组织变化的预报   总被引:1,自引:0,他引:1  
肖宏  谢红飚  毕恩复 《钢铁》2003,38(9):35-38
采用0rowan公式计算轧制过程中轧件应力应变、有限差分法计算温度变化,建立了板带热连轧生产过程温度变化、微观组织演变综合预报模型。用此模型对鞍钢现场轧制工艺进行了温度变化、奥氏体晶粒大小以及相变过程进行了解析计算,其预报值与现场实测结果吻合较好。  相似文献   

4.
采用有限元法对Ti-811合金棒材热连轧过程进行数值模拟,分析变形过程中轧件应力场、应变场和温度场的数值以及分布规律,并基于数值模拟结果进行轧制验证,为制定Ti-811合金棒材轧制工艺提供指导。结果表明:模拟连续轧制过程中轧件的最大应力位于与轧辊接触的表面,且由边部到心部逐渐降低;随着轧制道次的增加,应力值逐渐下降、应变量逐渐增大;轧件在各道次的变形过程中表层和心部存在差异,心部变形量大于边部变形量;轧件与轧辊接触的表面层有明显温降,当轧件脱离轧辊后表面层温度逐渐回升,轧制结束后表面层温度回升至初始温度,但心部因变形热积聚温度略有升高,最大温升值达到14℃。基于数值模拟结果在热连轧机组上进行轧制验证,所轧制的Ti-811合金棒材外形尺寸良好,且组织与力学性能满足GJB 9567—2018《叶片用TA11和TC6钛合金棒材规范》要求。  相似文献   

5.
无头轧制是一项发展中的新型轧制技术,其优势是没有轧件之间的时间间隔,作业率高、轧制过程稳定、工艺设备事故少,备件消耗低,产品质量好。重点介绍了该技术的开发过程、在板带和棒线材生产线上的各种工艺方式以及金属连接技术,并对无头轧制技术推广应用进行了展望。  相似文献   

6.
研究了连轧生产线生产的GH4648合金热轧棒材的组织与性能.采用热连轧过程的自动化控制系统调整棒材的轧制速度、保持稳定的终轧温度,从而获得晶粒组织均匀、α-Cr相形态与分布合理的热轧棒材.与传统的横列式轧机相比,工艺更稳定、可控,热轧棒材的组织稳定、性能提高.  相似文献   

7.
 采用计算机对高速线材生产过程进行模拟,开发出具有较高准确度同时具有对不同轧制工艺有较好通用性的高线生产仿真系统。利用有限元方法计算了线材在待轧、轧制、水冷及风冷过程的温度场;通过对再结晶动力学模型的解析,得到了静态再结晶、动态再结晶的分数以及奥氏体晶粒在轧制过程中的变化情况;通过组织演变模型和温度模型的耦合计算,模拟出斯太尔摩风冷线上线材的组织变化过程;建立了利用初始化学成分和组织组成预测高线产品力学性能的BP神经网络模型,通过生产过程数据的训练,实现了对线材力学性能的预测。仿真计算的结果对线材控轧、控冷工艺的改进有一定的指导意义。  相似文献   

8.
热连轧过程中的轧制力模拟   总被引:1,自引:0,他引:1  
 对目前用于带钢热连轧过程分析中的几种屈服应力模型进行了对比,并在此基础上改进了模型:用Orowan公式计算轧制过程中轧件的应力-应变,用有限差分法计算轧件的温度变化,建立了热连轧生产过程中温度变化和塑性变形计算相耦合的力能参数预报模型。用此模型对某钢厂热轧板带生产过程中力能参数的变化进行了解析计算。计算结果表明,模拟值与现场实测值吻合较好。  相似文献   

9.
开发了用于模拟高碳钢高速线材生产过程中断面温度分布,奥氏体组织演变和产品性能的系统数学模型组。由实验确定的临界应变、奥氏体再结晶、斯太尔摩冷却线上奥氏体相变、组织和力学性能关系子模型耦合轧件温度场,构建了一个组织性能预报系统。该系统所计算出的轧制线上关键点钢材温度,奥氏体晶粒度和力学性能与实测值吻合较好。  相似文献   

10.
太原科技大学秦建平教授总结我国棒线材生产取得的技术进步:(1)轧制技术水平提升。在高精度轧制、高速轧制、无头轧制、柔性轧制等方面收获了一系列成果:如低温轧制工艺,能够在线控制直条棒材和盘卷生产的晶粒度和工艺特性;在半连轧生产线采用的降低开轧温度、大压下、适当控温和控冷轧制、微合金化和高效冷却技  相似文献   

11.
12.
Two studies investigated the role of expressive vocal behavior (specifically, speech rate and loudness) in fear and anxiety and in sadness and depression. In the 1st study, participants spoke about personally experienced fear and anxiety-arousing and neutral events using 3 different voice styles: fast and loud, normal, and slow and soft. In the 2nd study, participants spoke about personally experienced sad or depressing and neutral events using the same 3 voice styles. In both studies, the participants' highest levels of subjective affective and cardiovascular (CV) arousal occurred when they spoke about the emotional events in a mood-congruent voice style: fast and loud in the case of fear and anxiety, and slow and soft in the case of sadness or depression. Mood-incongruent voice styles canceled the heightened levels of CV arousal normally associated with these negative emotions. The voice-style manipulation had no significant effect on the participants' levels of CV arousal during the neutral discussions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

13.
Despite the use of multimodal therapy, higher-grade glioma is still uniformly fatal in the adult population. There is a considerable difference between the length of survival in each given patient, even within the same tumor type and malignancy grade group, suggesting that there are factors that might differentially influence outcome. To identify such factors, 107 patients with anaplastic or malignant glioma were retrospectively investigated. Clinical parameters and paraclinical data on the p53, mdm2, and EGFR genes at the DNA or protein level were evaluated by univariate analysis and Cox proportional hazards regression modeling. Kaplan-Meier survival estimation demonstrated that immunohistochemical positivity for mdm2 protein in patients with anaplastic astrocytoma or with glioblastoma multiforme was associated with a shorter survival time (p = 0.02). P53 gene mutations and immunopositivity for the epidermal growth factor receptor (EGFR) protein were not significantly related to poor prognosis. The Cox proportional hazards model revealed immunohistochemical positivity for p53, mdm2, or for both of them, the presence of postoperative irradiation, and the extent of surgical resection of tumor to be variables significantly associated with prolonged survival. EGFR overexpression, age over 60 years, and Karnofsky performance score below 40 points did not significantly shorten survival time. In conclusion, the present study identified immunohistochemically detected mdm2-protein overexpression as a statistically significant negative prognostic parameter in patients bearing anaplastic or malignant glioma. Association analysis of variables revealed a possible correlation between mdm2 and p53, which is also consistent with the biological interaction mode of both proteins in vivo.  相似文献   

14.
BACKGROUND: As aging research increasingly reflects an effort to dissociate true time-driven changes from those that can be improved, sexuality in later life remains largely unexplored. Several problems are evident. There is a lack of normative data, a lack of a conceptual framework relating to the biology, psychology, and sociology of sex, and an attitudinal resistance that obscures the entire topic. METHODS: We conducted a three-part instructional series on major topics involved with sexuality and aging. We surveyed our group of attendees (n 158, average age 68 for males, 65 for females) before and after the series. RESULTS: A remarkably robust sex life was evidenced by both the men and the women, even until advanced old age. Yet, a substantially decreased involvement was reported from 10 years earlier. Despite current activities, people of both sexes wished they were participating even more than they currently were. Impotency was identified as the major negative feature for the men; relationship problems were for the women. A questionnaire 6 months after the series reported improved sexual attitudes, but no change in sexual activities from the earlier survey. CONCLUSION: Sexuality is a major quality-of-life issue which persists into old age. Our study showed that the usual sexual practices reported by our group were not considered by them to be ideal. The intervention of this instructional series provided improved sexual attitudes but not performance. Additional studies are encouraged.  相似文献   

15.
Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.  相似文献   

16.
OBJECTIVE: To test the validity of Benjamin Franklin's maxim "early to bed and early to rise makes a man healthy, wealthy, and wise." DESIGN: Cross sectional analysis of sleeping patterns in a nationally representative group of elderly people, and longitudinal investigation of mortality. SETTING: Eight areas in Britain (five in England, two in Scotland, and one in Wales). SUBJECTS: 1229 men and women aged 65 and over who in 1973-4 had taken part in a survey funded by the Department of Health and Social Security and for whom data on sleeping patterns, health, socioeconomic circumstances, and cognitive function had been recorded. MAIN OUTCOME MEASURES: Self reported income, access to a car, standard of accommodation, performance on a test of cognitive function, state of health and mortality during 23 years of follow up. RESULTS: 356 people (29%) were defined as larks (to bed before 11 pm and up before 8 am) and 318 (26%) were defined as owls (to bed at or after 11 pm and up at or after 8 am). There was no indication that larks were richer than those with other sleeping patterns. On the contrary, owls had the largest mean income and were more likely to have access to a car. There was also no evidence that larks were superior to those with other sleeping patterns with regard to their cognitive performance or their state of health. Both larks and owls had a slightly reduced risk of death compared with the rest of the study sample, but this was accounted for by the fact that they spent less time in bed at night. In the study sample as a whole, longer periods of time in bed were associated with increased mortality. After adjustment for age, sex, the presence of illness, and other risk factors, people who spent 12 or more hours in bed had a relative risk of death of 1.7 (1.2 to 2.5) compared with those who were in bed for 9 hours. The lowest risk occurred in people who spent 8 hours in bed (adjusted relative risk 0.8; 0.7 to 1.0). CONCLUSION: These findings do not support Franklin's claim. A "late to bed and late to rise" lifestyle does not seem to lead to socioeconomic, cognitive, or health disadvantage, but a longer time spent in bed may be associated with increased mortality.  相似文献   

17.
根据深云立交桥梁的检测结果,对该桥目前的整体状况、工作状态,及其使用情况做出综合评价,对桥的病害原因进行了分析,并提出合理的加固方案。  相似文献   

18.
众所周知,国际单位制物质的量采用摩尔(mol)表示,近几年出版的给排水专业书籍,为了与国际单位制接轨,逐渐将摩尔的使用频率不断提高,被给排水技术人员广泛应用的新版给排水设计手册,将表示物质浓度的单位“当量/升”或“毫克当量/升”.改为mol/l或mmol/l,虽然编者对其基本单元定义作了说明,但在实际运用上仍会出现误解,  相似文献   

19.
劳伦斯小说《儿子与情人》一个鲜明的语言特色就是标准英语和当地方言频繁的语码转换。莫瑞尔用方言来对抗妻子,而妻子坚持用标准英语,偶尔也用方言来讽刺、挖苦丈夫。语码转换反映了劳伦斯男女二元对立的哲学思想。  相似文献   

20.
介绍了抗腐蚀高强度耐磨涂料的研制和开发,以及用作柳钢球团回转烘干机刮板保护涂层的应用效果。  相似文献   

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