热连轧机板形板厚解耦控制的逆系统方法研究

提出一种解决热连轧机板形板厚解耦控制的逆系统方法；考虑热连轧机板形板厚的耦合性，在控制系统中加进一个“逆系统”，解耦线性化后，按照系统要求进行控制系统设计；在建立了热连轧机的非线性全量模型和线性增量模型基础上，分别构造了板形板厚解耦控制的非线性逆和线性逆解耦控制器，并用C语言编写了6机架仿真程序。通过仿真结果可以看出非线性逆的控制性能明显优于线性逆控制器。     

Understanding the Properties of Oxide Scales on Hot Rolled Steel Strip

Surface quality and downstream processability of hot rolled strip depend on tertiary scale thickness and composition at all process stages, from secondary descaling to the cold coil. TGA oxidation experiments provided the basis for quantitative modelling of scale growth during finishing hot rolling of low carbon steels (with or without Si or P). Finishing temperature (FT), gauge, and (particularly at the edges) coiling temperature (CT) are the main influence factors with respect to scale thickness. Based on HTXRD oxidation trials and microscopic analyses, trendlines are presented that roughly predict the final scale composition as a function of CT, for the coil centre and the edges. It appears that a CT of 400‐600°C, in combination with a coil centre position, is favourable for decomposed wustite, which is the preferred component for a good scale ad‐ and cohesion. Retention of wustite, the most preferred phase in the roll bite but very brittle at room temperature, is promoted by relatively high CTs (particularly with a coil quench) and by very low CTs. Hematite is formed at the edges in case of a high CT. This extremely hard phase is unwanted at any stage.     

Prediction of Microstructure and Mechanical Properties of Hot Rolled Steel Strip: Part I ‐ Description of Models

A metallurgical through‐process model is presented which describes the microstructural evolution and predicts the final mechanical properties of low carbon steel during hot strip rolling. Process models concern the thermal and deformation phenomena, which take into account the strain, strain rate and temperature distribution along the length of the strip. And the metallurgical models cover five modules, which are (i) austenitization of cast slab in reheating furnace, (ii) recrystallization of austenite in hot rolling, (iii) phase transformation of austenite‐ferrite in laminar cooling on the run‐out‐table, (iv) grain growth after coiling, and (v) final structure‐mechanical properties of products. Temperature is the main parameter and has dominant influence on the microstrutural evolution and the mechanical properties. The related temperature variation in hot strip rolling concerns air cooling, scaling, water cooling, heat transmission by roll contact, heat generation by deformation and friction. These complex factors are incorporated into the thermal models to simulate the temperature distribution along the length of the strip from the reheating furnace exit to the down‐coiler. A self‐learning algorithm is employed to improve the calculation accuracy and the computational temperatures are compared with the measured ones at typical locations. In the structure‐property relationships, two key process parameters (e.g., finishing exit temperature (FT7) and coiling temperature (CT)) are introduced in the model to consider the influence of morphology of microstructure on mechanical properties.     

Flow,Thermal and Microstructural Analysis during Cast Rolling of Steel in In‐line Strip Production Process

A mathematical model was developed to describe the in‐line hot rolling deformation and recrystallization behaviour of austenite after the solidification on a thin slab casting plant. The most significant features of the cast rolling process were taken into consideration: through‐thickness thermal gradients, inhomogeneous stress and strain, temperature discontinuity between the strip and the rolls. A HSLA (High Strength Low Alloy) steel has been chosen to perform the experiments of cast rolling. The characteristic constants ruling the microstructural evolution of that steel were computed and integrated into the computational module which manages the structural stress‐strain and strain rate computation. The developed approach is based on the Navier‐Stokes’ equations which were used to compute the speed field in the strip during the deformation. Then a model providing a proper constitutive equation was structured on the basis of the Yada's model based on evolution of the dislocation populations. The use of the Navier‐Stokes’ formalism allows to reach the resolution of the structural problem from the data measured easily during the industrial practice (i.e. speed of the rolled product at the entry and at the exit of a stand, the temperature of the rolled material). The validation of this computational approach was obtained by a comparison between the prior austenite grain size of the strip in different positions of the hot rolling process, as well as by a comparison between the computed deformation power and the measured one provided by the engines moving the rolls.     

基于变精度容差粗集的鲁棒分类器

该文基于目标识别中出现的不确定问题,提出了一种改进的粗集模型:变精度容差粗集模型。利用粗集中信息容量的定义,对不确定系统进行属性约减,并利用约减后的结果进行目标识别,仿真试验表明,利用该粗集模型进行目标识别时,具有较高的识别率和较高的鲁棒性。     

垃圾焚烧电站全厂控制系统的设计与实现

介绍了基于DCS系统的垃圾焚烧发电站自动化系统的设计与实现方案。该系统在掌握国外引进焚烧炉工艺的基础上,采取了自行设计配套生产的方法,系统设计涵盖了垃圾焚烧电站的所有主要设备。该系统成功投运为垃圾焚烧电站的调试和工艺改进提供了平台和基础,系统实用、稳定、可靠,是垃圾焚烧电站值得推荐的配套系统。     

切削深度对微细轴类零件加工精度影响的实验研究

金属切削过程中，不同的切削参数对零件的加工精度影响是不同的。通过车铣和车削两种加工方法的对比，重点研究了切削深度对微细轴类零件加工精度的影响问题。通过对实验结果的分析显示，车铣加工和车削加工微细轴时切削深度的变化对加工精度的影响很小，一般情况下可以忽略。     

砂带磨削的发展及关键技术

介绍了发展砂带磨削技术的意义及砂带磨削技术的发展趋势,通过比较国内外砂带磨削技术的差距,提出了促进我国砂带磨削技术发展的关键技术,包括新型砂带研制、高端精密高效砂带磨床研制、砂带磨床标准制定等方面。     

PC-based型高精度步进式位置伺服系统

利用运动控制板卡作为步进式位置伺服控制的上位控制器，构成了PC—based型高精度伺服控制系统，分析了一个双坐标步进式位置伺服系统控制方案。针对该系统的性能做了详细的分析，同时通过实验分析了该系统的定位精度和重复定位精度。     

1模32腔饮料瓶盖模具设计与制造

分析了饮料瓶瓶盖的结构和性能要求，对瓶盖的32腔模具设计了巧妙的脱模结构和稳定的热流道系统，并进行了强度计算论证。且在该模具制造中选用了合适的材料，提供了典型的部件加工工艺。