张力剪切的实际剪切实验研究

张力剪切是使被切件在受拉伸的状态下进行剪切,从而改善切头和剪切断面的形状,降低剪切力并使被切件提前断裂。本文用平行刃剪切机研究了张力对剪切断面、剪切力、断裂时相对切入深度的影响,设计了剪切模型的加载装置,得到了一点有益于设计和理论分析的结果。

冷连轧机带头飞翘原因分析与措施

在分析首钢京唐公司2230冷连轧机组带头飞翘原因的基础上，调整了轧机出口的剪切张力和剪切穿带速度，提出了加装磁铁，调整穿带速度，调整剪切张力和变厚度轧制等措施，成功解决了厚带钢带头飞翘问题，实现了稳定剪切穿带，显著降低了机组停机时间和废品量。

Experimental study of seismic cyclic loading effects on small strain shear modulus of saturated sands

The seismic loading on saturated soil deposits induces a decrease in effective stress and a rearrangement of the soil-particle structure, which may both lead to a degradation in undrained stiffness and strength of soils. Only the effective stress influence on small strain shear modulus Gmax is considered in seismic response analysis nowadays, and the cyclic shearing induced fabric changes of the soil-particle structure are neglected. In this paper, undrained cyclic triaxial tests were conducted on saturated sands with the shear wave velocity measured by bender element, to study the influences of seismic loading on Gmax. And Gmax of samples without cyclic loading effects was also investigated for comparison. The test results indicated that Gmax under cyclic loading effects is lower than that without such effects at the same effective stress, and also well correlated with the effective stress variation. Hence it is necessary to reinvestigate the determination of Gmax in seismic response analysis carefully to predict the ground responses during earthquake more reasonably.

铝及铝合金带材退火皱褶的产生原因及预防措施

皱褶是铝及铝合金带材生产中常见的缺陷,介绍了我公司带材退火过程中产生的皱褶,该缺陷形成的原因及其预防措施。

2230冷连轧机带头飞翘原因分析与措施

2 230mm西马克冷连轧机在生产过程中因轧机出口带头飞翘问题频繁停车,产线多次停车导致机组作业率下降,废品量明显上升。通过现场观察以及生产数据分析,调整了轧机出口的剪切张力,优化了剪切时序,规范了穿带速度,增加了变厚度轧制功能,机械人员在皮带助卷器加装磁铁。通过一系列措施,成功解决了厚带钢带头飞翘问题,实现了稳定剪切穿带,显著降低了机组停机时间,减少了废品量。