Pinyin: Ji m \u nqi

English: cut

Shear refers to the separation of materials by shear force.

Cutting in the computer:

Cut is to put the information you choose on the clipboard. After clicking Copy, you will get an extra copy. After the cutting operation, there is no such information in the original place.

The system clipboard is a dynamic space opened in memory, which is used to complete the copy and paste operation. In addition, many programs often use the clipboard of the system to complete specific tasks. So, if you want to see what is in the clipboard of the system, can you achieve your goal? In fact, you can directly call the special tools in the system to view and manipulate the contents of the clipboard (Windows XP is an example).

Run the "clipbrd" command to start the ClipBook Viewer gadget. The content will change immediately after the user performs the "copy" operation. In short, it always displays the contents of the current system clipboard. To clear the current clipboard, just click Edit-Delete. Of course, you can also save the contents of the current clipboard in the form of a file to a movie through "File-Save As" in the menu for later viewing.

Cut: After selecting a picture or text, use Ctrl+X command to cut the picture or text, put it on the computer cut version, and then use Ctrl+V to paste it in the position to be pasted. The process of cutting text is called cutting.

[Shear in engineering]

One of the basic deformation forms of engineering structural members.

Definition: under the action of a pair of lateral external forces which are very close to each other and in opposite directions, the cross section of the component is deformed in the direction of external forces.

Connectors in structures and machinery, such as bolts, pins and keys. When transmitting force, it is mainly subjected to extrusion (local pressure bearing) and shear deformation. In engineering calculation, the average shear stress obtained by dividing the shear force on the shear plane by its area is often used as the basis for strength calculation of this kind of direct shear members. The allowable shear stress is determined by dividing the shear stress when the component is damaged by the safety factor.

Shear in steel processing

English name: shearing

The rolled piece is cut by two cutting edges with linear motion, curvilinear motion or circular motion. The shearing process can be divided into two steps, that is, the blade presses into the metal (including elastic pressing and plastic pressing), and the metal slides until it breaks. The blade is made of carbon tool steel, alloy tool steel or hot die steel. Shearing machine is not only driven by motor, but also by hydraulic pressure. The layout of shears is determined by the use and production needs of various shears.

According to the temperature of the metal being cut, shearing can be divided into hot shearing and cold shearing (see cutting). According to the cutting direction of the metal to be cut, it can be divided into transverse shear and longitudinal shear. Cross shear is to cut off the head and tail of the rolled piece and cut the rolled piece into the required length. Longitudinal shears are used to cut off the irregular edges of rolled pieces in steel plate production, or to cut a wide band coil (or wide plate) into several narrow band coils (or narrow plates).

According to the shape and configuration of the blade and the situation of the rolled piece, the shears used for shearing can be divided into parallel edge shears, inclined edge shears, disc shears, flying shears and rolling shears.

Parallel blade scissors The two blades of this pair of scissors are parallel. (Figure 1a) When cutting, the lower edge can be fixed, and the cutting action is completed by the upper edge (upper cutting shear), or the upper edge presses the rolled piece, and the cutting action is completed by the lower edge (lower cutting shear). Usually, it is used for hot shearing bloom, square billet, rectangular billet and flat billet with thickness greater than 30 ~ 60 mm, and sometimes it is also used for cold shearing rolled pieces with holes and grooved blades (such as tube billets and small round steel). The shape of the hole and groove should be the same as that of the cut rolled piece. The upper-cutting shearing machine has a simple structure, but it needs to be equipped with a swinging table or a swinging roller table behind the shearing machine, which is widely used for shearing billets or extra-large slabs (the cross section is 350mm×2400mm). Because the upper and lower edges are moving in the shearing process, the structure of the lower shearing machine is more complicated than that of the upper shearing machine, but the shearing end face is neat, and the end of the workpiece to be sheared is not easy to bend. Moreover, because the steel is higher than the roller surface during shearing, there is no need to set a swinging lifting roller table behind the shearing machine.

Inclined-blade shearOne blade of the inclined-blade shears forms a certain angle with the other blade. (Figure 1b) Generally, the upper blade is inclined, the inclination angle is 1.5o ~ 6o, and when cutting thick plates, it is 8o ~ 12o, and the lower blade is horizontal. Because the contact area between the blade and the rolled piece is small and the shearing force is small, this kind of shearing machine is often used for cold shearing or hot shearing steel plate, strip steel, thin slab and welded pipe blank, and also for shearing bundled small steel products. Inclined-edge shears can also be divided into upper cutting type and lower cutting type. In recent years, the hydraulic undercut bevel shears have been widely used. This kind of shearing machine has the advantages of simple and compact structure, light weight, stable shearing and automatic overload prevention, but its productivity is low and it needs motor power.

The two blades of the disc shearing machine are made into a disc shape (Figure 2a) for shearing the edges of steel plates and steel strips; When the steel plate or steel strip is longitudinally cut into narrow strips, it is necessary to use multiple pairs of blades. Disc shears are generally arranged on steel plate finishing line or hot and cold steel longitudinal shearing line. The thickness of the strip steel to be cut is usually less than 20 ~ 40 mm In order to expand the range of the cutting thickness, some countries use two disc shears arranged in series to cut the steel plate with a thickness of about 38 mm The first disc shears the steel plate to 5% ~ 10% of the thickness, and then the second disc shears the steel plate.

Flying shears are used to roll workpieces in transverse shearing motion. (Figure 2b) This shearing machine is generally installed on the production lines of continuous rolling mill, crosscutting unit and tinning unit in cold and hot strip steel workshops, and is used to cut the head and tail of the rolled piece to a certain length.

Rolling shear is a shearing machine for shearing steel plates developed in 1970s (Figure 3). It cuts an arc-shaped upper cutting edge by rolling it on a straight lower cutting edge. Because the sliding amount of the upper cutting edge relative to the section of the steel plate is small, and the overlapping amount of the upper cutting edge and the lower cutting edge on the total cutting edge length is the same, the section of the steel plate is smooth and straight. Compared with inclined-blade shears, circular-arc rolling shears have the advantages of light equipment weight, high shearing frequency and less operation accidents.