飞剪板坯动态测长装置设计原理

我厂的板坯在线剪切生产线,虽然有许多优点,如自动化程度高、剪切速度快等等,但仍存在板坯定尺调整不准等缺点。为了完善飞剪线控制系统,研制了飞剪板坯动态测长装置,主要是开发IBM—PC/XT计算机的应用软件。这里分三部分(飞剪定尺原理、测量设计思想、软硬件设计)对其设计原理进行了详细地分析和论述,并对运行情况加以肯定。     

棒材启停式倍尺飞剪综述

倍尺飞剪的剪切长度及优化剪切效果直接影响产品的成材率和定尺率,本文主要叙述了连轧棒材车间启停式倍尺飞剪的结构型式、工作制度和工艺要求,对其剪切精度和操作方法进行了介绍,给出了优化剪切的基本思路和控制要求,希望能为相关设计人员和操作人员提供参考。     

基于目标定尺长度的滚筒飞剪传动控制参数计算方法

深入研究了滚筒飞剪连续定尺剪切原理,建立了目标定尺长度计算模型,形成比较完善的基于目标定尺长度的滚筒飞剪传动控制参数计算方法。以某汽车板重卷检查机组的滚筒式飞剪机为例,编制程序,进行了控制计算,计算速度快,精度高,完全满足工程需要。     

数字技术在棒材成品飞剪电控系统的应用

为了解决棒材成品飞剪剪切倍尺精度不高,成材率和定尺率低,切损大,没有实现优化剪切等问题,在技术改造中采用了全数字电控系统,使飞剪剪切精度提高,由原来的剪切误差200 mm缩小到100 mm以内,有效提高了成材率和定尺率,对于现场备件储备和维护都比较方便,有效的提高了设备作业率.     

气动离合式（CV型）高速棒材飞剪机动态特性分析研究

揭示了ＣＶ型飞剪机的运动与动作特征，通过建立ＣＶ型高速飞剪机响应系统的数学模型，分析了影响系统动态特性的主要参数、传动系统的载荷特征、影响剪切定尺与定位精度的主要因素和补偿方法。可为提高剪机剪切精度及优化系统结构参数提供设计参考。     

曲柄摆式飞剪设计与计算相关问题研究

利用静力学方程对一种广泛使用于连续退火线上的曲柄摆式飞剪进行了分析,并以此为基础论述了该型飞剪电机功率的计算方法,同时也对剪切过程中飞剪电机转速与机组带钢运行速度的匹配关系以及该型飞剪的定尺剪切特性进行了论述。     

双鼓式单摆槽可调速飞剪

鞍钢小型厂一车间制违了一台双鼓式单摆槽可调飞剪。飞剪由一台55千瓦直流电机带动,剪切速度为5.1～15.3米/秒,可剪切钢材长度为9米、12米定尺或倍尺,剪切效果良好。但在剪切小规格钢材时容易发生轧件头部运行不稳窜出辊道现象,有待进一步改进。     

德国UNGERER飞剪控制原理的简介

定尺飞剪是板带精整线的重要组成部分，昆钢板带冷轧1725mm剪切线横切机组使用德国UNGERER飞剪设备，这是目前世界上最先进的飞剪设备之一。通过总结飞剪的应用，对飞剪控制原理及控制系统进行阐述，有利于昆钢加快消化吸收引进的先进技术。     

棒材倍尺飞剪的控制与优化

对棒材生产线上倍尺飞剪系统配置及控制方法进行分析，并对优化剪切提出解决方案，提高了倍尺飞剪的剪切精度。     

棒材倍尺飞剪的优化控制

棒材倍尺飞剪控制主要包括轴定位和分段剪切控制两大部分，一般情况下容易出现剪刃位置控削不准和钢材长度测量不精确的问题，影响剪切精度和控制稳定性。介绍的优化控制方法是在常规控制的基础上，利用新的控制思路和控制方法实现对倍尺飞剪的优化控制，控制精度较高，稳定性较好。     

用轴向气胎式离合器,制动器改造旧飞剪

采用轴向式气胎离合、制动器，改造了旧飞剪，解决了原剪机电磁离合、制动器控制不准确的问题；该剪机改造后在成品轧机后使用，剪切用１２０ｍｍ×１２０ｍｍ坯生产的大规格产品（１８ｍｍ以上），增产、增效，年总经济效益为９７．８万元     

新型摆动式分段圆盘飞剪的结构与分析

文章介绍了新型摆动式分段圆盘飞剪的工作原理与结构，与下轴浮动式圆盘飞剪相比，该新型剪机的结构简单，受力合理，刚度及剪刃寿命提高，且维修方便     

Strength Characteristics of Class F Fly Ash Modified with Lime and Gypsum

This paper presents the shear strength characteristics of a low lime class F fly ash modified with lime alone or in combination with gypsum. Unconfined compression tests were conducted for both unsoaked and soaked specimens cured up to 90 days. Addition of a small percentage of gypsum (0.5 and 1.0%) along with lime (4–10%) enhanced the shear strength of modified fly ash within short curing periods (7 and 28 days). The gain in unsoaked unconfined compressive strength (qu) of the fly ash was 2,853 and 3,567% at 28 and 90 days curing, respectively, for addition of 10% lime along with 1% gypsum to the fly ash. The effect of 24?h soaking showed reduction of qu varying from 30 to 2% depending on mix proportions and curing period. Unconsolidated undrained triaxial tests with pore-pressure measurements were conducted for 7 and 28 days cured specimens. The cohesion of the Class F fly ash increased up to 3,150% with addition of 10% lime along with 1% gypsum to the fly ash and cured for 28 days. The modified fly ash shows the values of Skempton’s pore-pressure parameter, Af similar to that of over consolidated soils. The effects of lime content, gypsum content, and curing period on the shear strength parameters of the fly ash are highlighted herein. Empirical relationships are proposed to estimate the design parameters like deviatoric stress at failure, and cohesion of the modified fly ash. Thus, this modified fly ash with considerable shear strength may find potential use in civil engineering construction fields.     

连轧厂粗轧机后切头飞剪的改型与设计

介绍了长钢连轧厂粗轧机后切头飞剪的改进,选型设计及其启停式飞剪的使用效果和特点。     

型钢全连轧引进飞剪电控系统分析

意大利杰泰公司的飞剪及电控系统,在天津轧三制钢有限公司小型车间实现全连轧改造中,解决了冷床短的问题,并提高了剪切精度。文章就该飞剪的电控系统进行了分析。     

Time Effect on Shear Strength and Permeability of Fly Ash

This paper investigates the effect of time on the shear strength and the permeability of fly ash, a major solid by-product of thermoelectric power plants. Direct shear tests using Mikasa's apparatus, conventional permeability tests, and consolidation tests were conducted on two silt-size fly ashes, with low free lime contents, obtained from two different power plants. The results show that the immediate settling of both fly ashes takes place in a short period of time during consolidation and does not change with time. The rate of increase in shear strength with time is different depending on the pozzolanic reactions taking place for the two ashes. The permeability tests under constant stresses of 49 and 98 kPa for 12 days show that the coefficient of permeability for the tested ashes is between 10?6 and 10?7 m∕s. During this period the coefficient of permeability either remains constant (for the case of the ash with a lower free lime content) or is slightly reduced (for the ash with a higher free lime content). The practical implications and the limitations of using low lime silt-size fly ash in vertical drains in the stabilization of soft ground are also discussed.     

Effect of Fly Ash on Engineering Properties of Expansive Soils

This note presents a study of the efficacy of fly ash as an additive in improving the engineering characteristics of expansive soils. An experimental program has evaluated the effect of the fly ash content on the free swell index, swell potential, swelling pressure, plasticity, compaction, strength, and hydraulic conductivity characteristics of expansive soil. The plasticity, hydraulic conductivity and swelling properties of the blends decreased and the dry unit weight and strength increased with an increase in fly ash content. The resistance to penetration of the blends increased significantly with an increase in fly ash content for a given water content. Excellent correlation was obtained between the measured and predicted undrained shear strengths.     

2250横切飞剪剪切长度异常原因分析及对策

通过长期的观察和分析,针对2 250横切飞剪在生产过程中出现的剪切长度异常现象,总结出了钢板出现剪切长度异常的各种原因。从2 250横切飞剪的控制系统入手,提出了一种解决剪切长度异常的方案;通过测量辊和夹送辊之间的差值,判别是否出现剪切长度异常并及时通知操作人员。通过实际生产应用证明了该方案的可行性,该方案的应用大幅度提高了钢板剪切的成材率,避免由于飞剪剪切异常而造成的经济损失。     

小型全连轧改造精整工段电控系统

轧三半连轧改造后,冷床上钢动作由电控系统发出信号控制电机来完成,不能满足高速生产要求,在全连轧改造中,采用电控系统控制液压缸来完成上钢动作,适应了16m/s轧制速度要求,解决了飞剪至冷床距离短的问题,满足了生产工艺要求,提高了产量,取得了经济效益。     

On the Comparison of Timoshenko and Shear Models in Beam Dynamics

The classical Timoshenko beam model and the shear beam model are often used to model shear building behavior both for stability or dynamic analysis. This technical note questions the theoretical relationship between both models for large values of bending to shear stiffness parameter. The simply supported beam is analytically studied for both models. Asymptotic solutions are obtained for large values of bending to shear stiffness parameter. In the general case, it is proven that the shear beam model cannot be deduced from the Timoshenko model, by considering large values of bending to shear stiffness parameter. This is only achieved for specific geometrical parameter in the present example. As a conclusion, the capability of the shear model to approximate Timoshenko model for large values of bending to shear stiffness parameter is firmly dependent on the material and geometrical characteristics of the beam section and on the boundary conditions.