Effect of width-to-thickness ratio and thickness profile changing on the critical instable shape during cold strip rolling

Based on the volume constancy with equal flow-per-second and elastic sheet stability theory, a coupling relationship among lateral thickness difference, width-to-thickness ratio of cold rolling strip steel under ideal and actual working conditions, and shape is concluded according to the comprehensive influence principle of various factors on the critical instable shape analyzed in-depth. Firstly, the influence model under actual working condition is developed by referring to the basic relationship between lateral thickness difference and shape under ideal condition. The test results prove that for thin strips with thickness below 0.3 mm, their lateral thickness differences have significant effect on the shape. After then, the combined influence of lateral thickness difference and width-to-thickness ratio on the critical instable shape is concluded according to the elastic sheet stability model, with the synthetic effect of these three factors analyzed. Test data indicate that for cold rolling strip steel with width-to-thickness ratio above 3 000, the critical instability stress difference decreases significantly. Actual measurements are conducted on the lateral thickness differences of two rolls of typical strip manufactured by a sixhigh cold mill, with the influence law of lateral thickness variation and width-to-thickness ratio comprehensively investigated. It is demonstrated that during the production of ultrathin strip steel with different width-to-thickness ratios, the loading roll shapes should be fine adjusted according to the lateral thickness difference of input strips.Therefore, the variation of lateral thickness difference of output strips can meet the requirement of shape stability,so as to obtain fine shape.     

热烈祝贺中国路面机械网建网5周年

2007年10月18日中国路面机械网借着第九届北京国际工程机械展览与技术交流会的召开,在北京农展馆举行了建网5周年庆典仪式。     

改造后的南京机场高速公路的收费监控系统建设

高速公路的迅猛发展，与之相配套的监控、收费、通讯等交通信怠工程也迅速发展起来，并发挥越来越大的作用。介绍南京机场高速公路以前的收费监控系统状况，通过改造所发生的变化；阐述收费监控系统所发挥的作用。     

海上测量设备电源自动保温系统设计与实现

在海上试验中,无人测量船的测量设备大都由蓄电池进行供电。在冬季时,海上环境温度较低,蓄电池低温损耗严重,进而导致测量设备无法正常工作。因此,论文设计一种设备电源自动保温系统,可有效地解决蓄电池低温损耗的问题。     

运输价格:适当疏导从严控制

成品油价格调整之后,为稳定终端的运输价格,国家发改委,财政部和交通运输部昨日联合发出通知,要求各地缓解成品油调价对交通运输业的影响,严格控制连锁反应.     

New Approach to Measuring Traffic Queue at Intersections

To measure the length of traffic queue, a vehicle motion model at intersections was built, and based on it the effective traffic queue was defined. Color images segmentation and frame differencing technique were used to detect the foreground and the moving vehicles by detecting regions of the images, and then measure the length of effective traffic queue. By processing the image sequence acquired at certain intersection, the results prove that it is able to work out the traffic queue effectively by using the two techniques.     

试述国外引进设备的消化吸收

目前我国高速公路建设发展迅速,很多高速公路都同期建成了现代化的监控、收费和通信系统,其中有一部分是从国外引进的产品.对于从国外引进的设备如何消化吸收它的新技术并保证它的正常运转是我们的工作重点与目标,而且也是一个复杂的系统工程.南京机场高速公路的收费和监控系统全套从西班牙引进,至今为止该套设备已正常运转四年多,本文以南京机场高速公路收费系统为例,结合实际工作体会,试述国外引进设备的消化与吸收.