降低板坯连铸机漏钢率的改进措施

在分析板坯连铸机在生产过程中出现的漏钢事故基础上,实施工艺优化和设备改进等措施。改进后,大大降低了漏钢事故,取得了显著的效果。     

Biomorphs with memory

An exploratory study is made on the dynamics of discrete maps in the complex plane endowed with memory of past iterations. The study deals with the generalized breakout condition that generates the so called biomorphs, i.e. a kind of Julia sets whose form reminds to that of certain types of living microorganisms. Metamorphosis of a biomorph with memory of degree alpha     

板坯连铸机粘结漏钢分析及控制

针对板坯浇铸过程中发生的粘结漏钢事故,从设备状态、保护渣、连铸操作等方面进行分析,认为拉速控制不当是本次事故主要原因,提出相应的预防措施,避免了该类事故的再次发生。     

含TiO2的保护渣在高温下生成TiN、Ti（CN）的研究

使用含TiO2较高的原料或人为地在保护渣中加入TiO2,可以降低结晶器内渣膜的传热能力,但是该类渣在现场长期使用后会出现连铸粘结和漏钢比例大幅上升的情况,造成这一问题的可能原因是该类保护渣在熔化过程中形成了TiC、Ti(C、N)等高熔点物质,从而引起粘结漏钢。本文通过热力学计算以及实验室研究证实了在含TiO2保护渣使用过程中生成TiC等高熔点物质的可能性。     

可燃气体气缸内燃烧仿真计算与试验

可燃气体仿真计算包括气体在缸内工作过程的计算和改进气管内流动过程的仿真计算，研究可燃气体在气缸内的实际工作情况对研制天然气机有指导性的作用。通过理论计算和对比试验，发现气体燃烧有规律可寻，为设计提供理论依据。     

An investigation of machine learning techniques to estimate minimum horizontal stress magnitude from borehole breakout

Borehole breakout is a widely utilised phenomenon in horizontal stress orientation determination, and breakout geometrical parameters, such as width and depth, have been used to estimate both horizontal stress magnitudes. However, the accuracy of minimum horizontal stress estimation from borehole breakout remains relatively low in comparison to maximum horizontal stress estimation. This paper aims to compare and improve the minimum horizontal stress estimation via a number of machine learning (ML) regression techniques, including parametric and non-parametric models, which have rarely been explored. ML models were trained based on 79 laboratory data from published literature and validated against 23 field data. A systematic bias was observed in the prediction for the validation dataset whenever the horizontal stress value exceeded the maximum value in the training data. Nevertheless, the pattern was captured, and the removal of systematic bias showed that the artificial neural network is capable of predicting the minimum horizontal stress with an average error rate of 10.16% and a root mean square error of 3.87 MPa when compared to actual values obtained through conventional in-situ measurement techniques. This is a meaningful improvement considering the importance of in-situ stress knowledge for underground operations and the availability of borehole breakout data.     

Breakout of a slab as the result of changes in the thermophysical properties of continuously cast steel

The so‐called secondary cooling zone is an important part of the continuous casting machine. In this zone, a breakout may occur because of an increase of the local and temperature heterogeneity of steel, resulting from an increase of the stress caused by bending of the slab and by high local concentration of nonmetallic slag inclusions. Changes of the chemical composition of steel during continuous casting are particularly dangerous. In the event that two melts are cast one after another, that is, if the melt of steel with chemical composition A ends and is immediately followed by the steel B, it may automatically stop the continuous casting machine, and an atypical breakout may take place. It has happened during continuous casting of the slab, 250 × 1530 mm in the area of straightening, 20 min after flying change of tundish. In the present paper, by employing the dimensional analysis, eight dimensionless numbers are derived. If the values of these dimensionless numbers for two followed steels significantly differ, the atypical breakout may take place.     

Experimental observation and analysis of burr formation mechanisms in face milling of aluminum alloys

The purpose of this paper is to study the burr formation mechanisms in face milling process, and to investigate the influence of cutting conditions on burr formation in face milling of aluminum alloys. The fly milling cutter is used to carry out single-tooth face milling tests. Three aluminum alloys were tested: Al 1100 (cold drawn), Al 2024-T4 and Al 6061-T6. It is found that the burr geometry is strongly dependent upon the in-plane exit angle. Five types of burrs were observed in the experiments: knife-type, wave-type burr, curl-type, edge breakout and secondary burr. Formation mechanisms of each type of these burrs are discussed in details. The relationship between their existence and the machining condition is indicated. The machining guideline in face milling is given at the end of the paper to reduce burr size effectively through the formation of secondary burr.     

基于改进模糊ART神经网络的连铸漏钢预报模型

在模糊ART神经网络的基础上,有机结合模糊模式识别和模糊聚类算法,并通过引入新的学习机制和优化网络结构,建立了改进的新型模糊ART神经网络模型;同时,结合某钢厂连铸现场采集的历史数据,将该模型应用于连铸漏钢预报过程中。其结果表明,该模型对粘结漏钢过程中2种典型温度模式的预报率分别达到956%和978%,报出率都达到100%,且在避免漏报的同时保证了较低的误报率,能准确识别典型的温度模式和预测拉漏事故的发生。     

连铸粘结漏钢的结晶器温度变化及其传播行为

以国内某钢厂板坯连铸粘结漏钢的实测样本为基础,重点调查了铸坯粘结时结晶器热电偶温度变化,分析了粘结传播行为,讨论了现行热电偶布置合理性和漏钢预报模型的设计.研究结果表明:粘结时单个热电偶温度在时间上表现先升后降变化规律,且具有一定温度变化速率和持续时间,多行多列相邻热电偶温度变化在空间上表现粘结传播的"时滞性",具有典型性,同列热电偶温度变化表现"温度倒置"现象,但不具典型性;粘结纵向传播速度小于拉速,与拉速呈线性正相关,横向传播速度与拉速比为 0.91 ~ 1.91,存在较大不稳定性;从纵横向检测快慢和稳定性综合考虑,以纵向检测为主、横向检测为辅设计漏钢预报模型更为合适;现行热电偶布置较为合理.