三辊楔横轧机机架结构参数的研究

本文用有限元法计算并分析了三辊楔横轧机机架的应力,得出了机架各部位的应力状态及应力值,绘制了典型断面及机架外廓的主应力图。针对机架应力集中严重部位,对其结构与参数作了研究,找出了合理的结构参数值,为机架的改造和设计提供了理论依据。     

确定楔横轧工艺参数的模糊推理方法

运用模糊信息处理方法,通过对大量的楔横轧模具设计的实际数据进行模糊处理,进而得出断面收缩率φ与成形角α、展宽角β的模糊关系.依据模糊关系,选择合理的推理方法,确定出工艺参数,解决了模具设计智能CAD中工艺参数的自动选取问题．     

船舶领域研究综述

通过对现有船舶领域模型进行分类综述和分析,总结基于各类研究方法的主要研究成果及其主要特点,剖析其存在的主要问题,阐明船舶领域研究的核心思想和意义,明确提出船舶领域研究的几个具有理论和实际意义的可能的研究方向.     

工艺参数对楔横轧特大型轧件内部应力影响分析

楔横轧成形特大型轧件为复杂的三维变形，其内部应力变化规律复杂，至今缺乏深入研究与本质理解，严重影响楔横轧的应用与发展。采用有限元先进数值方法模拟楔横轧特大型轧件成形过程，详细分析成形过程中轧件内部中心点的应力变化规律，阐明成形角、展宽角和断面收缩率三个主要工艺参数对特大型轧件内部应力的影响关系，为合理选取楔横轧特大型轧件模具工艺参数、开发设计特大型楔横轧机提供重要的理论依据。     

一种基于参数绘图的H630楔横轧机模具CAD方法

介绍一种用ＡｕｔｏＣＡＤ二次开发工具进行Ｈ６３０楔横轧机模具设计的方法．这种模具ＣＡＤ（ＣｏｍｐｕｔｅｒＡｉｄｅｄＤｅｓｉｇｎ，计算机辅助设计）方法是一种基于参数绘图的方法，在输入主参数后，由计算机完成其他设计参数计算和参数自动绘图，并可根据需要选择模具不同的设计内容输出．     

工艺参数对楔横轧多楔轧制成形机理影响分析

针对楔横轧多楔精密轧制长轴类零件中工艺参数的确定主要依靠经验、轧件缺陷频繁发生的难题,采用自主开发的多楔命令流有限元程序对多楔轧制过程进行有限元数值模拟,从理论上较详细分析成形角、展宽角和断面收缩率三个主要工艺参数对轧件内部等效应力、应变和轴向位移的影响,得到其相应的变化规律,并对断面收缩率对轴向位移的影响规律进行实验验证.     

板坯角部横裂纹综述

分析总结了板坯角部横裂纹的特点及其对轧制产品的影响,对板坯角部横裂纹的产生机理、影响因素进行了系统综述,归类总结了预防板坯角部横裂纹产生的措施。通过对比,发现采用倒角结晶器解决板坯角部横裂纹的措施效果较好。     

宽幅带材横磁感应加热技术的发展

根据感应器的形式及其激发的电磁场方向,感应加热可分为纵向磁通感应加热和横向磁通感应加热两种方式。在对比介绍横向磁通感应加热和纵向磁通感应加热各自概念和技术特点的基础上,着重评述了宽幅带材横磁感应加热技术发展的几个典型案例,并结合宝钢横磁感应加热的最新研究进展,探讨了横磁感应加热技术工业应用的若干关键问题。最后,通过历年相关专利和论文数量的统计分析,展望了横磁感应加热技术的发展趋势和应用前景。     

工艺参数对楔横轧无台阶端头轧件料头体积损耗影响规律

采用DEFORM-3D软件对无台阶端头轧件的成形过程进行了有限元数值模拟,并结合二次回归正交旋转组合设计法,研究了各工艺参数对无台阶端头轧件料头体积损耗的影响规律,得到了轧件料头体积的回归方程.研究表明,轧件的料头体积与轧制长度成正比,与展宽角成反比,在模具设计允许的条件下,宜选用较小的展宽角.通过轧制实验,验证了回归方程的可信度和影响规律的正确性.     

工艺参数对楔横轧二次楔轧制超大断面收缩率轴类件的影响

为考察楔横轧二次楔轧制在超大断面收缩率情况下的成形规律,在H630轧机上进行了不同工艺条件下的超大断面收缩率轧制实验,得到各工艺参数对轧制质量的影响规律,发现在超大断面收缩率情况下二次楔的工艺参数对内部缺陷和拉断加工界限有决定性影响.结果表明,只要参数得当,二次楔轧制可以获得合格的大断面收缩率轴类件.     

微小型硬质合金工作辊的研究

微小型硬质合金工作辊的生产工艺比较繁长,它包括粉末的选择、冷成型、机加工、预烧结、热等静压处理、研磨加工等一系列工艺过程。该工艺于1994年底通过部级鉴定。本文重点叙述各阶段内容及研制过程中的工艺特点。     

倒角对变接触支撑辊辊形性能的影响

 辊间接触应力分布直接影响轧辊疲劳状态与磨损状态,进而影响支撑辊的使用寿命。在支撑辊辊形为VCR+条件下对不同倒角长度与倒角深度的54种工况采用二维变厚度有限元模型进行仿真分析,论证了在不同倒角条件下辊间接触应力峰值大小与位置的变化关系,并提出了倒角性能参考量来评估倒角形式对轧辊疲劳失效的影响。最终根据有限元分析结果结合支撑辊下机磨损状态提出了在VCR+辊形条件下倒角优化方式,为现场支撑辊倒角优化提供了理论与实践依据。     

Influenza A outbreak on a cruise ship

Data are presented from an investigation of the use of monophasic contraceptive pills chosen by different age groups. Analyses are made of the data obtained from the Bulgarian Association for Family Planning (BAFP) card index for the last two years. Information is given on the number of observed cycles, type of applied contraceptive pill, aims of their application (contraception, treatment of acne, menstrual disturbances etc.), age of patients, as well as any possible adverse effects--change in blood pressure, bodyweight changes, intermenstrual bleeding, hairiness, breast problems, paraclinical changes, etc. The observed cycles show a very small percentage of adverse effects with hormonal contraception, mainly during the first 2 or 3 cycles, with predominance of intermenstrual bleeding. No bodyweight changes or increased hairiness were observed.     

A precision on-line model for the prediction of roll force and roll power in hot-strip rolling

Investigated via a series of finite-element (FE) process simulations is the effect of diverse process variables on some selected nondimensional parameters characterizing the thermomechanical behavior of the strip in hot-strip rolling. Then, on the basis of these parameters an on-line model is derived for the precise prediction of roll force and roll power. The prediction accuracy of the proposed model is examined through comparison with predictions from a FE process model and also with measurements.     

连铸辊断裂失效分析研究

采用成分分析和金相分析等方法,对连铸辊断裂原因进行了分析。结果表明:堆焊层存在较多夹杂物,并在高温下形成尖锐裂纹源;连铸机发生"夹辊",造成局部温度剧烈升高,加快裂纹的扩展;坯辊锻造后的晶粒较粗大,S局部沿晶界分布,降低了坯辊的韧性,也促进裂纹的扩展。     

辊式矫直过程弯辊量对边浪影响的仿真分析

针对辊式矫直过程建立具有边浪特征的带钢有限元仿真模型,通过对比现场工况实测矫直力与有限元模型计算所得的矫直力,得到二者误差在10%以内,验证了有限元模型的精度。分别采用原始曲率补偿法和塑性变形层增加法确定了4种弯辊量设定方案。采用上述方案对浪高为20 mm的带钢进行矫直,对比矫直后带钢平直度情况,得出按最高浪采用原始曲率补偿法计算得到的弯辊量矫直效果最优。同时随着弯辊量的加大,矫直力也随之增加,为现场边浪矫直过程提供了依据。     

Evaluation of deterioration mechanisms and roll life of different roll materials

Evaluation of wear loss of rolls in operation is very difficult since the rolling conditions are hard to keep under control. To solve this problem a high temperature test rig was designed. A conventional roll material was compared to a hot work tool steel. The main wear mechanisms were different. The conventional roll grade was mainly subjected to thermal fatigue as could be expected. The hot work tool steel was mainly subjected to abrasive wear, and no evidence of thermal fatigue was found. The rate of material loss was 6 times higher in the hot work tool steel, but when the deterioration caused by thermal fatigue of the cast iron is taken into consideration, the deterioration rate was of the same order in both materials. The friction between the hot steel and the roll materials were of the same order. The frictional value should be a measure of the wear rate. Since the wear mechanisms are not equal, the coefficient of friction found in the test rig is only qualitatively related to roll wear.     

优化UF轧机重轨辊环参数及提高轧辊利用率

针对万能轧机UF精轧机重轨轧辊辊环利用率低的情况,对轧机轧制工艺参数进行可行性分析,通过采取增大轧辊辊环直径的措施,提高了轧辊辊环的利用率。     

A mathematical model of single roll strip caster based on macroscopic enthalpy balances

A mathematical model, based on the overall heat balance and the growth of solidification front, has been formulated to describe the single-roll strip-casting process for steel. The model provides useful interrelationships between the rate of growth of solidifying strip and the principal process variables such as the speed of rotation of caster drum, the system geometry, the superheat of melt and the relevant heat transfer coefficients. Using these relationships it has been possible to predict the effect of process parameters on the process performance in terms of the final strip thickness and the casting rate.