一. Introduction to Steel Rolling Machinery
轧钢机是实现金属轧制过程的设备。泛指完成轧材生产全过程的装备﹐包括有主要设备﹑辅助设备﹑起重运输设备和附属设备等。但一般所说的轧机往往仅指主要设备。
A steel rolling mill is a device that realizes the metal rolling process. It generally refers to the equipment that completes the entire process of rolling production, including main equipment, auxiliary equipment, lifting and transportation equipment, and auxiliary equipment, etc. But when people generally refer to rolling mills, they usually only mean the main equipment.
二、轧钢机的命名
二. Naming of the Steel Rolling Mill
按轧制品种﹑轧机型式和公称尺寸来命名。“公称尺寸”的原则对型材轧机而言﹐是以齿轮座人字齿轮节圆直径命名﹔初轧机则以轧辊公称直径命名﹔板带轧机是以工作轧辊辊身长度命名﹔钢管轧机以生产大管径来命名。有时也以轧机设计者的名字来命名 ( 如森吉米尔轧机 ) 。
It is named according to the rolled variety, the type of rolling mill and the nominal size. For profile rolling mills, the principle of "nominal size" is named after the pitch circle diameter of the herringbone gear in the gear seat. The primary rolling mill is named after the nominal diameter of the rolls. The plate and strip rolling mill is named after the length of the working roll body. Steel pipe rolling mills are named for producing large pipe diameters. Sometimes it is also named after the designer of the rolling mill (such as the Sendzimir rolling mill).
三、轧钢机的选择
三.Selection of Steel Rolling Mills
按生产的产品品种﹑规格﹑质量和产量的要求来选定成品或半成品轧机的类型和尺寸﹐并配备必要的辅助﹑起重运输和附属设备﹐然后根据各种因素的要求最后加以平衡选定。
The type and size of the finished or semi-finished product rolling mill should be selected based on the requirements of the product variety, specification, quality and output to be produced, and necessary auxiliary, lifting and transportation, and auxiliary equipment should be equipped. Then, a final balanced selection should be made according to the requirements of various factors.
四、轧钢机的组成部分
四.Components of the Steel Rolling Mill
1、工作机座:由轧辊﹑轧辊轴承﹑机架﹑轨座﹑轧辊调整装置﹑上轧辊平衡装置和换辊装置等组成。
2、轧辊:是使金属塑性变形的部件 。
3、轧辊轴承:支承轧辊并保持轧辊在机架中的固定位置。轧辊轴承工作负荷重而变化大﹐因此要求轴承摩擦系数小﹐具有足够的强度和刚度﹐而且要便于更换轧辊。不同的轧机选用不同类型的轧辊轴承。滚动轴承的刚性大﹐摩擦系数较小﹐但承压能力较小﹐且外形尺寸较大﹐多用于板带轧机工作辊。滑动轴承有半干摩擦与液体摩擦两种。半干摩擦轧辊轴承主要是胶木﹑铜瓦﹑尼龙瓦轴承﹐比较便宜﹐多用于型材轧机和开坯机。液体摩擦轴承有动压﹑静压和静 - 动压三种。优点是摩擦系数比较小﹐承压能力较大﹐使用工作速度高﹐刚性好﹐缺点是油膜厚度随速度而变化。液体摩擦轴承多用于板带轧机支承辊和其它高速轧机。
4、轧机机架:由两片“牌坊”组成以安装轧辊轴承座和轧辊调整装置﹐需有足够的强度和钢度承受轧制力。机架形式主要有闭式和开式两种。闭式机架是一个整体框架﹐具有较高强度和刚度﹐主要用于轧制力较大的初轧机和板带轧机等。开式机架由机架本体和上盖两部分组成﹐便于换辊﹐主要用于横列式型材轧机。此外﹐还有无牌坊轧机。
5、轧机轨座用于安装机架﹐并固定在地基上﹐又称地脚板。承受工作机座的重力和倾翻力矩﹐同时确保工作机座安装尺寸的精度。
6、轧辊调整装置:用于调整辊缝﹐使轧件达到所要求的断面尺寸。上辊调整装置也称“压下装置”﹐有手动﹑电动和液压三种。手动压下装置多用在型材轧机和小的轧机上。电动压下装置包括电动机﹑减速机﹑制动器﹑压下螺丝﹑压下螺母﹑压下位置指示器﹑球面垫块和测压仪等部件﹔它的传动效率低﹐运动部分的转动惯性大﹐反应速度慢﹐调整精度低。 70 年代以来﹐板带轧机采用 AGC( 厚度自动控制 ) 系统后﹐在新的带材冷﹑热轧机和厚板轧机上已采用液压压下装置﹐具有板材厚度偏差小和产品合格率高等优点。
7、上轧辊平衡装置:用于抬升上辊和防止轧件进出轧辊时受冲击的装置。形式有﹕弹簧式﹑多用在型材轧机上﹔重锤式﹐常用在轧辊移动量大的初轧机上﹔液压式﹐多用在四辊板带轧机上。
为提高作业率﹐要求轧机换辊迅速﹑方便。换辊方式有 C 形钩式﹑套筒式﹑小车式和整机架换辊式四种。用前两种方式换辊靠吊车辅助操作﹐而整机架换辊需有两套机架﹐此法多用于小的轧机。小车换辊适合于大的轧机﹐有利于自动化。目前﹐轧机上均采用快速自动换辊装置﹐换一次轧辊只需 5 ～ 8 分钟。
8、传动装置: 由电动机﹑减速机﹑齿轮座和连接轴等组成。齿轮座将传动力矩分送到两个或几个轧辊上。
9、辅助设备包括轧制过程中一系列辅助工序的设备。如原料准备﹑加热﹑翻钢﹑剪切﹑矫直﹑冷却﹑探伤﹑热处理﹑酸洗等设备。
1. Working base: It is composed of rolls, roll bearings, frame, rail seat, roll adjustment device, upper roll balancing device and roll changing device, etc.
2. Rolls: They are components that cause plastic deformation of metals.
3. Roll bearings: Support the rolls and keep them in a fixed position within the frame. The working load of the roller bearings is heavy and varies greatly. Therefore, the bearings are required to
have a small coefficient of friction, sufficient strength and rigidity, and be easy to replace the rollers. Different rolling mills select different types of roll bearings. Rolling bearings have high rigidity
and a low coefficient of friction, but their pressure-bearing capacity is relatively small. Moreover, they have a large external dimension and are mostly used in the work rolls of plate and strip rolling
mills. There are two types of sliding bearings: semi-dry friction and liquid friction. Semi-dry friction roller bearings are mainly bakele, copper bearing and nylon bearing. They are relatively inexpensive
and are mostly used in profile rolling mills and blank opening machines. There are three types of liquid friction bearings: dynamic pressure, static pressure and static-dynamic pressure. The
advantages are that the coefficient of friction is relatively small, the pressure-bearing capacity is large, the working speed is high, and the rigidity is good. The disadvantage is that the oil film thickness
varies with the speed. Liquid friction bearings are mostly used in the support rolls of plate and strip rolling mills and other high-speed rolling mills.
4. Rolling mill stand: Composed of two "archways" for installing the roll bearing housing and the roll adjustment device, it must have sufficient strength and rigidity to withstand the rolling force. The
main forms of racks are closed type and open type. The closed frame is an integral frame with high strength and rigidity, mainly used in primary rolling mills and plate and strip rolling mills with large
rolling forces. The open frame consists of two parts: the frame body and the upper cover. It is convenient for changing rolls and is mainly used in cross-type profile rolling mills. In addition, there are
also rolling mills without archways.
5. The rolling mill rail base is used to install the frame and fix it on the foundation, also known as the base plate. Bear the gravity and overturning moment of the working base, while ensuring the
accuracy of the installation dimensions of the working base.
6. Roll adjustment device: It is used to adjust the roll gap to make the rolled piece reach the required cross-sectional dimensions. The upper roller adjustment device, also known as the "downward
pressure device", comes in three types: manual, electric and hydraulic. Manual pressing devices are mostly used in profile rolling mills and small rolling mills. The electric press-down device includes
components such as an electric motor, a reducer, a brake, a press-down screw, a press-down nut, a press-down position indicator, spherical pads and a pressure gauge. Its transmission efficiency is
low, the rotational inertia of the moving parts is large, the response speed is slow, and the adjustment accuracy is low. Since the 1970s, after the AGC(Automatic Thickness Control) system was adopted
in strip and sheet rolling mills, hydraulic pressing devices have been used in new cold and hot strip rolling mills and thick plate rolling mills, which have the advantages of small thickness deviation of
the sheet and high product qualification rate.
7. Upper roll balancing device: A device used to lift the upper roll and prevent the rolled piece from being impacted when entering or leaving the roll. The forms include: spring type, mostly used in
profile rolling mills; Heavy hammer type, commonly used in primary rolling mills with large roll movement; Hydraulic type, mostly used in four-high plate and strip rolling mills.
To enhance the operation rate, it is required that the rolling mill change its rolls quickly and conveniently. There are four types of roller changing methods: C-shaped hook type, sleeve type, trolley
type and whole machine frame roller changing type. The first two methods of changing rolls rely on the assistance of a crane, while changing rolls on a complete frame requires two sets of frames.
This method is mostly used for small rolling mills. Trolley roll changing is suitable for large rolling mills and is conducive to automation. At present, all rolling mills are equipped with rapid automatic
roll changing devices, and it only takes 5 to 8 minutes to change a roll once.
8. Transmission device: It is composed of an electric motor, a reducer, a gear seat and a connecting shaft, etc. The gear seat distributes the transmission torque to two or several rolls.
9. Auxiliary equipment includes a series of devices for auxiliary processes during the rolling process. Such as equipment for raw material preparation, heating, steel flipping, shearing, straightening,
cooling, flaw detection, heat treatment, pickling, etc.
