大型初轧机受料辊道和工作辊道的改进

大型初轧机受料辊道和工作辊道,以往均采用用通轴径由锥齿轮传动辊子的结构形式。针对该结构存在问题,在新设计的大型初轧机上,对这两种辊道的结构和传动形式,做了较大改进。本文即介绍受料辊采用圆柱齿轮传动形式和工作辊道采用单独传动和圆柱齿轮分组传动形式结构特点及进一步改进的情况。     

管轧机单独传动辊道结构型式比较

一、辊道的种类和传动方式辊道种类按其用途可分为工作辊道、运输辊道;按在轧机前、后位置可分为输入辊道、输出辊道;按驱动方式则可分为集中传动、单独传动辊道。集中传动辊道(图1,上图)是一台电机经过减速器、传动轴、伞齿轮传动每个辊子。一台电机可带十几个辊子。单独传动辊道(图1,下图)是由一台电机经过减速器直接传动一个辊子。目前在现场两种传动型式都使用。     

攀钢2#方坯连铸热送辊道优化改造实践

本文分析了攀枝花钢钒有限公司提钒炼钢厂2#方坯连铸热送辊道的电机、减速机、辊子轴频繁故障的原因,提出了根据辊道部位采取不同的传动方式:公路桥下采用集中传动方式,其余部分采用单辊传动形式.并对不同部位辊道的减速机、电机、联轴器、轴承的选型及安装方式都进行了优化改造.改造后的2#方坯连铸热送辊道在实际生产中运行良好.     

出炉辊道结构和冷却方式的改造及应用

轧钢生产线出炉辊道位于加热炉炉门处,温度高,轴承座冷却不足易烧轴承。本文简要介绍出炉辊道由集中传动改为单传动并改变辊子结构后,取得的良好效果。     

一种高性能的齿轮传动：内啮合弧齿锥齿轮传动

1.概述锥齿轮是在相交轴之间传递机械运动和动力的零件,其种类很多,目前应用最广的是外啮合锥齿轮传动,如图1a所示。但是,锥齿轮传动并不都是外啮合。在轴交角大于90°的斜交锥齿轮传动中,当传动比和轴交角满足一定条件时,大齿轮的节锥角将会大于90°,这意味着它的轮齿必须分布在内锥面上,即成了内锥齿轮,此时在背锥展开图中,当量圆柱齿轮就成了内啮合圆柱齿轮,如图1b所示,这种锥齿轮传动就称为内啮合锥齿轮传动。具有圆弧齿的内啮合锥齿轮称为内啮合弧齿锥齿轮。     

小方坯连铸机出坯辊道优化分析

针对某六流小方坯连铸机输送辊道所采用集中链条传动方式存在驱动装置和传动机构复杂、故障率高、维修工作量大的问题,拟进行改造.提出了通轴的结构形式和单独传动的方案,对改进后输送辊道主要结构进行了有限元计算和分析,并对其进行验证.     

新型集中传动辊道制造技术

在新型集中传动辊道制造过程中,如何保证圆锥齿轮的轮位正确性是制造关键,本文在误差分析的基础上,论述了补偿制造误差的检配技术和热装轴向收缩间隙误差控制技术。     

锥齿轮传动箱效率计算方法比较研究

本文主要对三种锥齿轮传动箱效率的计算方法进行了比较研究，而且与锥齿轮传动箱的试验效率作了对比，对锥齿轮传动效率的计算方法进行了论证。     

工艺受限时弧齿锥齿轮切齿参数的计算

针对弧齿锥齿轮传动的综合问题,阐述了弧齿锥齿轮切齿参数在刀具成形半径受限、展成链传动比受限、刀具成形半径和展成链传动比同时受限3种条件下机床调整的计算方法,为满足弧齿锥齿轮传动啮合质量,即局部接触斑点尺寸范围、旋转传动相对均匀性,提供了切实可行的思路,并用典型计算实例,演示了弧齿锥齿轮磨齿机床参数调整的步骤和方法.     

提高辊道使用寿命的方法

运输辊道是轧钢厂的重要辅助设备。其传动方式是通过伞齿轮付相互啮合来传递扭距的。辊道检修频繁,使用寿命短。其直接原因是伞齿轮付不能正确啮合,导致运动中产生冲击负荷,使伞齿轮和轴承寿命大为降低。尤其是轧机前后辊道,正反转频繁,辊道使用寿命极低。     

Automated guided vehicle system design for FMS applications

The issues of designing and installing a system of Automated Guided Vehicles (AGVs) in a Flexible Manufacturing System (FMS) are examined in this work. The development, advantages and future trends of AGVs are briefly reviewed. Then the basic features of an AGV in an FMS environment, as well as a computerized procedure for the optimum vehicle selection, are discussed. Guide path layout considerations are made and docking/pallet transfer methods are suggested. A routing algorithm is presented to facilitate both routing and control of the vehicles, and the most commonly used methods for zone blocking, loading/unloading and traffic control and communications are outlined. Operation rules are reviewed and an example of an AGVS in an FMS is presented to demonstrate the potential of simulation in both design and evaluation of such systems.     

Characterization of an electrical melting point using a focusing transducer

The thickness resonances of an elastic plate normally insonified by an ultrasonic plane wave are well known. From these resonance frequencies, the plate thickness can be easily deduced. In this paper, we use a focusing ultrasonic transducer with a large bandpass to characterize an electrical melting point between two steel plane shells. This solder type is abundantly used in the manufacturing of cars. The solder is placed in the focal spot of the beam. The transducer can be parallely moved to the surface of the sheet steel. A number of time signals are recorded along a diametrical line of the melting point with a small step. For each time signal, two spectra are computed: the magnitude spectrum also called backscattered spectrum and the phase spectrum. The results are processed with graphic software. The different images allow the evaluation of the quality of an electrical melting point.     

油箱上体拉深件口部曲面构造

曲面的构造是曲面拉深件设计中的关键环节。以油箱上体为例,建立了曲面边界线方程,依此边界构造了双三次混合Coons曲面,根据曲面的第一和第二不变量求得其曲面曲率,并作出曲率分布图,为拉深工艺分析和模具设计提供依据。     

Relaxation of Output Characteristics of Electrohydrodynamic Pumps

The principle of operation of an electrohydrodynamic pump (EHDP) is explained. Research problems are formulated for the study of the patterns and peculiarities of the operation of the EHDP for the purpose of its optimization. The experimental facility is described and the peculiarities of the relaxation of the output characteristics of a single-stage EHDP are determined. The dependences of the pressure and current characteristics on the time and voltage (dc) supplied to the EHDP are presented. New results related to very long operation of EHDPs are revealed, e.g., the fact that the pressure characteristics are fluctuating time functions. A theoretical model of the electric current transfer in an EHDP is presented, which is based on an analog electrical circuit.     

Inverse Analysis of Heat Conduction in Hollow Cylinders with Asymmetric Source Distributions

This paper presents an application of inverse analysis for determining both the temperature field histories and corresponding heat source distributions in hollow cylinders. The primary goal, however, is the development of an inversion infrastructure in a manner that allows taking advantage of all aspects related to its utility, including sensitivity analysis. The conditions generating heat sources are those resulting from intense pulsed-current electrical contact experiments. Under these conditions intense heat currents are generated due to the Joule conversion of the electric conduction currents. Asymmetry of the heat source is induced from the localized melting due to arc-enhanced electric conduction. Experimentally acquired temperature histories and melting domain boundary data are utilized to setup an inverse model of the heat conduction problem. This permits the construction of an estimate not only of the temperature field histories throughout the computational domain but also of an evaluation of the effective thermal diffusivity of the material involved.     

The rutile type and its derivatives†

Rutile type crystal structures and their derivatives are based on the same topology of primary bonds: straight chains of edge-sharing coordination octahedra are connected via corner-sharing to four surrounding chains. Twenty derivatives are known. Some are based on an ordering of cations, others on an ordering of anions, others still on distortions of their coordination polyhedra. The overwhelming majority of all the compounds reviewed here crystallize in the aristotypic rutile type. The trirutile type, an ordering variant, and the CaCl₂ type, a distorted rutile, are also numerous. The other rutile type derivatives are known only from one, two, or just a few examples. Most of the known compounds obey Pauling's postulate, as expressed in his second rule for complex ionic compounds, according to which the sum of the bond strengths received by an anion should be balanced for stable compounds by the formal valence of that anion. More than one half of all naturally occurring chemical elements have been observed to be present in the rutile type or its derivatives.     

The Case for Chromium

Chromium, as an alloy base for high-temperature construction service, is discussed. The expectations for the metal and its technological limitations are approached from an historical point-of-view, and recent developments in chromium technology are discussed. In addition to the physical and strength properties of the metal, processing techniques, availability, and cost are discussed. The future prospects for this metal in high-temperature service are reviewed.     

800H合金的高温抗氧化性能

利用X射线衍射仪(XRD)、扫描电镜(SEM)和能谱仪(EDS)等,对800H合金高温氧化膜的增厚动力学、形貌及氧化物组成进行了分析。结果表明,700和800℃下形成的氧化膜相近,由(Cr,Fe)2O3和Mn-Cr氧化物组成;900℃时的氧化膜急剧增厚,里层依然是Cr2O3,中间层则是Cr-Fe-Mn氧化物,外层为富Ti的氧化物。通过热力学和动力学计算,提出了800H合金氧化膜形成的模型,发现TiN的存在改变了氧化膜的结构。     

Effects of aging in electric field on 2024 alloy

The effect of heat treatment in an electric field on micro-plastic deformation characteristics of 2024 Al alloy was investigated. The mechanism of aging in an electric field affecting the micro-plastic deformation behavior was preliminarily discussed. The results show that the resistance to micro-plastic deformation of the alloy can be greatly increased by aging in an electric field. Aging temperature, aging time and electric field strength are selected by adopting the orthogonal design method and the optimum technological parameters are obtained.     

Boundary element methods for the analysis of crack growth in the presence of residual stress fields

Two boundary element methods of simulating crack growth in the presence of residual stress fields are presented, and the results are compared to experimental measurements. The first method utilizes linear elastic fracture mechanics (LEFM) and superimposes the solutions due to the applied load and the residual stress field. In this method, the residual stress fields are obtained from an elastoplastic BEM analysis, and numerical weight functions are used to obtain the stress intensity factors due to the fatigue loading. The second method presented is an elastoplastic fracture mechanics (EPFM) approach for crack growth simulation. A nonlinear J-integral is used in the fatigue life calculations. The methods are shown to agree well with experimental measurements of crack growth in prestressed open hole specimens. Results are also presented for the case where the prestress is applied to specimens that have been precracked.