When and why is metal straightening done?
Metal straightening is the process of eliminating irregularities on the surface of a material. The operation applies to both blanks and finished parts. The main reasons: the shape of the product does not correspond to the specified parameters, as a result of convexity, curvature or warping. Editing the material is possible at home.
Sheet metal straightening
Straightening sheet metal is one of the simplest operations. It is carried out to bend thin material. To do this, the sheet is placed on a plate or anvil. The amount of curvature is determined by the gap between the metal and the cast iron plate.
The hammer strikes the convex part of the surface. To prevent the material from bending in the opposite direction, the sheet is constantly turned over. As the curvature decreases, the force of the impacts decreases.
If there are several irregularities, the lateral defects are eliminated first, and then the central curvature.
Why is editing needed?
Rolled products produced by metallurgical methods are used as a starting material for hot or cold stamping. Therefore, products must meet all GOST standards:
- sheets and strips are checked for flatness;
- round rods with permissible bending value;
- square rods on the degree of bulging or concavity of the metal.
It is important to know when to correct distortion of the workpiece shape. If such a defect is present, there is a risk of damage to the stamping equipment. The curved workpiece, falling into the plane of the stamp, is formed by a punch and a matrix.
In addition, editing of products is necessary in the following cases:
- when cutting sheet metal using guillotine shears;
- when pushing the finished part out of the die cavity;
- after metal shrinkage;
- after heat treatment.
Types of metal straightening
There are the following types of metal straightening:
In the first case, the work is carried out at home. Mechanical straightening can be carried out both with a heated part and in a cold state. Often a hot stamping die consists of several strands. The last of these is used to level the part after it has been formed in the previous streams. When the two halves of the stamp are closed, the finished product is refined
In sheet stamping, in addition to preliminary alignment of the metal sheet, editing is necessary after certain operations:
- When bending and stretching, the correct bend radius and the amount of rounding are not always formed. In this case, the stamp is lowered to its lowest position. All residual stresses are eliminated and the part acquires the required parameters.
- If the sheet thickness is large, separate dies are made for straightening. A grid of small teeth is applied to the working parts of the instrument. Alignment occurs at the moment of closure of both halves of the stamp.
Straightening equipment
Editing of metal products in production conditions is carried out on machines. The following equipment is used for this:
- Correct rollers. As a tool, shafts are installed, between which metal is passed. The pressure is calculated so that it is enough to correct the defect, but does not exceed the plasticity of the material. Often the equipment is automated and therefore has high productivity. Rolls come in different shapes, so not only sheet metal, but also rods are passed between them.
- Press. They require the installation of stamps. Often editing, also called embossing, is combined with other operations in one die.
Working with sheet metal, equipment review
In case of manual straightening, the following tool is used:
- Cast iron plates. Characterized by heavy weight.
- Straightening headstocks. Used for working with hard materials.
- Hammers. Depending on the metal being processed, there are different configurations.
- Sledgehammers. The same hammers, only heavier. They are used if the hammer impact force is not enough to deform.
- Mallets - a wooden hammer.
- Ironing irons. They are made of wood and are designed to level metal.
Mallet for straightening metal
How to straighten metal
Sheet metal straightening can be done at home. The editing methods are as follows:
- Convex. Such a defect is eliminated by striking a hammer around the circumference, starting from the very edge. Movement towards the center follows a spiral trajectory. Gradually, the force of the blows decreases, and their frequency increases. If there are several bulges, then they are combined with hammer blows into the intermediate part, between the defects.
- Undulation. Eliminated using the same technology. Work is carried out from the edges of the sheet to the center. As a result, the defect is eliminated by stretching the metal.
The bending of the strip metal is removed by striking the convex part. Then the workpiece is turned over. If the bulge has moved to the other side, it is also eliminated.
The difficulty lies in straightening hardened parts with shaped surfaces. A straightening headstock is used here. The workpiece is placed on it, and blows are applied to the concave part of the surface. In this case, the material is stretched and it is leveled. Hardened round-shaped metal is used as strikers.
If you need to straighten a hardened corner by 90°, then in the case of an acute corner, blows are applied on the inside of the corner, and in the case of a blunt corner, on the outside.
Square metal rods are straightened in the same way as strip. A workpiece with a square or round cross-section is placed on a slab, and blows are applied to the protruding surface. As the bar is straightened, it turns over.
Stretched metal (Lessons pdr) Auto Jeweler - removing dents.
Metal straightening in industrial production conditions is carried out on specialized equipment that is designed for these purposes.
At home, this is done with your own hands using a hammer and a massive plate.
When and why metal is straightened Link to main publication
Source: https://metalloy.ru/obrabotka/sgibanie/pravka-metalla
Manual straightening of sheet metal
Manual straightening of sheet metal. 4.36/5 (87.27%) lost 11
Sheet and section metals are usually straightened on straight plates with blows of a sledgehammer.
The sizes of the slabs are 1.5 X 1.5 m; 2.0 X 2.0 m; 1.5 X 3.0 m. As a rule, regular slabs are cast from gray cast iron, ribbed or solid solid. The working surface of the stove must be flat. Sometimes such slabs line the entire area of the correct room.
The slabs are installed on wooden beams, with a working surface height from the floor of 400-650 mm. The main tools for straightening on a slab are hammers and sledgehammers.
Correct hammer handle. Hammer weight. Sledgehammer weight.
The working surface or head of these hammers and sledgehammers is flat or slightly convex, depending on the location and nature of the blow required.
They are usually made with different surfaces at the ends - double-faced, as well as with an elongated and narrow striker. The weight of hand hammers varies from 3/4 to 1 ½ - 2 kg. The weight of sledgehammers ranges from 5 to 15 kg.
Handles for hammers and sledgehammers are made of strong, hard wood - elm, dogwood, rowan, birch, etc., and are secured in the socket with an iron wedge.
Hammer handle length.
Depending on the weight of the hammer or sledgehammer, the handle is given the appropriate length (Table 1).
Table 1. Hammer handle length depending on weight.
| Weight of hammer or sledgehammer in kg | Handle length in mm | Weight of hammer or sledgehammer in kg | Handle length in kg |
| 0,25 | 250 | 4 | 700 |
| 0,3 – 0,4 | 300 | 4,5 | 750 |
| 0,5 – 1,0 | 360 | 5 – 6 | 800 |
| 1,25 – 2,0 | 425 | 7 – 8 | 850 |
| 2,5 – 3,0 | 475 | 9 | 900 |
| 3 – 3,25 | 550 | 10 | 1000 |
| 3,5 | 650 |
Shape of hammers and sledgehammers.
The shapes of hammers and sledgehammers are shown in Fig. 1.
Rice. 1. Hammer and sledgehammer.
Rice. 2. Ironers.
The smoothers used for straightening have different shapes; samples of them are shown in Fig. 2. Some smoothers (2, a and d) are inserted with their shanks into the holes of a special handle, while the rest (2, b, c and d) are mounted on wooden handles like hammers.
For various metal profiles, trowels of various shapes are used.
Metal straightening technology.
It is impossible to give precise instructions on how to edit. Editing skills are acquired through experience. We can only note some basic editing techniques. The main technique for manually straightening metal is to hit the metal with a hammer or sledgehammer. To straighten metal, they mainly use the so-called shoulder blow, i.e.
such a blow, in delivering which all joints of the arm work: shoulder, elbow and hand. This provides the necessary force to the strike. The force of the blow depends on the weight of the hammer and, mainly, on the speed of the blow. This speed depends on the magnitude of the swing and on the force that is applied to move the hammer downwards.
High productivity with minimal fatigue of the body is achieved by a certain rhythm in work, i.e.
over a certain time, you need to make a certain number of working movements, using all means to eliminate unnecessary effort, for example, using the recoil force of the hammer from the metal when lifting it up to deliver the next blow.
Equally important is the ability to choose the right place to strike, ensuring straightening of the metal. There is curvature of the sheets in the form of one or several bulges in the middle of the sheet between its stretched edges or a stretched middle of the sheet with wavy edges.
Rice. 3. A sheet of metal with a bulge in the middle (a) and at the edge (6).
The numbers show the sequence of hammer blows.
Buckling indicates that at this location the surface area of the metal is greater than the area where the bulge occurred. To straighten such a bulge, you need to direct the hammer blows not at it, but at the metal around it and in such a sequence as to gradually release the tense areas (Fig. 3, a).
If you strike the bulge, the metal will spread out under their influence, and the bulge will increase. When there are several bulges on the surface of the sheet, blows are applied to the metal in the isthmuses between them, bringing all the bulges into one common one, and then the blows stretch the tense surface of the metal. With a wavy leaf edge (Fig.
3, b) blows are applied to the stretched part of the metal, the metal stretches, and the waviness disappears.
The surface of the straightened sheet is checked with a metal ruler, which is applied edgewise to the sheet in different directions. The gap between the sheet and the ruler is measured with a feeler gauge.
Method of straightening metal. Metal deposition.
Sectional metal is usually processed by upsetting (planting) and bending, and only in rare cases is spreading (stretching) of the metal used.
It is straightened by hand on a slab or on special anvils with cutouts (Fig. 4). Metal is placed on the sides of the anvil cutout with the side opposite to the one that will be struck.
Rice. 4. Anvil for manual straightening of shaped metal:
1 - straightened metal; 2 — anvil with cutouts.
Sectional metal with a curvature along a helical line is straightened in a cold state by twisting in the opposite direction using lever devices (forks). In case of significant curvature, the profiles are straightened while hot.
Tool for straightening metal. Screw yoke.
When straightening bar metal, various devices are used.
One type of such device is a screw yoke (Fig. 5). The straightening process consists of installing a curved profile into the yoke body and straightening it by pressing the screw on the corner from the convex side. Straightening of section metal with a screw yoke proceeds slowly.
Rice. 5. Screw yoke:
1 - screw with tape thread; 2 — yoke body; 3 - straightened metal (corner).
When straightening, you need to pay special attention to stainless steels of type 18-8. Due to the tendency to intergranular corrosion, it is prohibited to straighten sheets of this steel by hitting them with a steel sledgehammer. When straightening, it is necessary to use either copper sledgehammers, or use copper smoothers, or copper backing sheets. The plates are thoroughly cleaned before straightening stainless steel sheets onto them. Local heating with a gas burner is not permitted.
Source: https://mechanicinfo.ru/ruchnaya-pravka-listovogo-metalla/
Metal straightening and straightening, plumbing
The profile of locksmiths is constantly expanding and segmenting, which is associated with the emergence of new tasks. At the same time, the basic list of operations performed by specialists in this area is also preserved. The most common types of processing of this kind include cutting, chopping, straightening and bending metals for various purposes. Such operations are performed by plumbers, tool makers, and car mechanics.
Material cutting
One of the most common processing operations that allows you to divide the workpiece into separate parts. Cutting can be done either manually or mechanized. In the case of a manual approach, hacksaws, scissors, gas-flame torches and pipe cutters can be used. But this tool is not able to cope with thick and high-strength workpieces.
At the very least, the process will be labor-intensive and will not produce a high-quality product. For this reason, straightening, bending, cutting metal and other metalworking operations are often performed on machines. In particular, turning models of equipment are used for cutting. The highest quality cutting is provided by plasma and waterjet machines.
The direction of the sandblasting flow onto the material ensures high-precision cutting of thick workpieces, regardless of the quality of the alloy.
In some ways, this is a type of cutting, but of a different nature of execution. Also, the working tool in this case differs from standard cutting. Chisels, groovers and cross-cutters are used for cutting. For example, using a chisel, you can separate a layer of a metal surface, cut a workpiece into pieces, make grooves or make a hole.
However, the possibilities for realizing complex forms of harvesting through cutting are limited. In this sense, straightening and bending of metals are more productive operations. Cutting is used in situations where, for various reasons, it is impossible to use machine processing and high demands are not placed on the workpiece in terms of the accuracy of the parameters.
For example, if it is necessary to remove excess mass for subsequent processing with files, the sharpening tool will, if necessary, correct the shape formed by the same chisel.
Using straightening, the master changes the shape of the metal workpiece, restoring its previous appearance after damage. For example, the entire complex of straightening work in auto repair shops can be attributed to the operations of straightening and bending metals, during which curvatures, dents, swelling, warping and other defects are eliminated.
Carrying out such work is possible both under the condition of thermal influence on the workpiece and in its cold state. However, heat softens the metal, which gives the performer an advantage.
As for the tools, in the manual format, hammers, anvils, pliers, mallets, hydraulic presses and clamping mechanisms are used.
The mechanized method is implemented using machine presses and straightening rollers. Separately, it is worth noting the straightening stand (slipway), which, due to its great effort, allows for the correction of massive structures.
Manual straightening and bending of metal can also be done on the stocks. Tools in the form of a vice and clamping mechanisms make it possible to eliminate complex deformations when interacting with the complete equipment of the stand.
Such complex operations are usually performed at the sites of the same auto repair shops.
Metal bending
This operation allows you to give the product a curved shape in accordance with a given contour. During the working procedure, the workpiece is subjected to compressive and tensile forces, which are provided by a special tool. In particular, bending is carried out using vices, pliers, presses and the above-mentioned clamps.
As you can see, straightening and bending of metals are similar in that they involve the simultaneous use of a whole group of tools, some of which provide fixation of the workpiece. But in this case there are also some nuances in terms of bending technique. For example, it is not recommended to allow a bend radius that will be less than the thickness of the product.
Ignoring this rule may lead to the formation of a crack in the structure of the material.
Other operations
Of course, the range of processing procedures is much larger. For example, there is a whole layer of corrective methods that allow you to accurately model the shape of a product. Similar operations are performed with files, needle files and rasps.
An even more important segment of work is represented by installation operations, which are performed after cutting, straightening and bending the metal. Plumbing in this area involves the operations of connecting, tightening, installation manipulations, etc.
In installation work, pliers, ratchets, screwdrivers, the same hammers with pliers, as well as small fasteners and consumables are used. After all, we should not forget that the listed processing operations are carried out for specific purposes for the further use of the product - this can be in production areas, auto repair shops, and household use.
For example, at home, a restored section of a deformed plumbing pipe or cutting a profile for a roof can be used.
Conclusion
When choosing a suitable method for processing a metal workpiece, you should focus on the work conditions and the capabilities of the tool. The characteristics of the workpiece itself deserve special attention. Straightening and bending metals with a soft structure is one thing, and cutting tool steel with a thickness of more than 20 mm is another.
In each case, means that are appropriate in terms of technical and operational parameters must be used. It would also be useful to take into account auxiliary methods to support the processing operation.
These include the same thermal effects, melting, the use of stocks, compressor units and other equipment that facilitates the work performed.
Source: https://respect-kovka.com/pravka-i-rihtovka-metalla-slesarnoe-delo/
Methods for straightening metals and the tools used. What is metal straightening
Category: Locksmith work
Metal straightening
Section, shaped and sheet steel from which various parts or workpieces are made are sometimes bent or warped. To eliminate these defects, before processing the metal, an operation called straightening is performed.
Metal straightening is carried out in a cold or heated state.
In cold straightening, strip, square, round and angle steel are secured in a chair vice at the bent area and the bent areas are manually straightened by bending them in the opposite direction of the bent, and then the metal is straightened with a hammer on an anvil or plate.
The steel is leveled on the anvil by striking the raised areas with the wide head of a hammer, turning the material from one side to the other until it is level. The straightness of the steel is checked by eye.
The force of the impact depends on the degree of curvature and thickness of the material. If there is a large curvature or a significant thickness of the material, stronger blows are applied at first, and as the material straightens, the blows weaken. You should not apply very strong blows, as the material will be flattened and warped.
If the strip steel is bent along a narrow edge, then the curved part is laid with the wide side on the plate, then, pressing the steel to the plate with the left hand, the right hand strikes with the hammer strike along the wide side of the curved part, first strong, along the concave edge, then gradually weakening the blows, leveling convex edge of the strip.
When straightening angle steel, if the strip is curved towards the edge, the strip is laid on a shelf on the plate and struck with a hammer on the edge; if the strip is bent towards the shelf, the strip is laid on the edge of the plate or anvil and the shelf is struck, gradually straightening the angle steel strip.
Metal sheets are straightened by hand. Thin sheets are laid on the slab with the convex side up. Hammer blows are applied starting from the edge of the bulge to the middle. The blows are applied weaker along the edges of the bulge, and intensified towards the center.
Thick sheets are sledgehammered hot or cold in the same way as thin sheets.
When straightening while hot, the sheet is heated in a furnace or on a forge to 600-700 °C (red heat).
To protect your hands from bruises when straightening metal, you must wear gloves, use proper tools, and firmly hold the straightened material on the plate or anvil.
Straightening is used in cases where it is necessary to eliminate distortion of the shape of the workpiece - waviness, warping, dents, bending, bulging, etc. Metal can be straightened both cold and heated. Heated metal is much easier to straighten, but this is also true for other types of its plastic deformation, for example, bending.
At home, straightening should be done on an anvil or a massive plate of steel or cast iron. The working surface of the stove must be smooth and clean. To make the impact sound less loud, the stove should be placed on a wooden table, which can also be used to level the stove so that it is in a horizontal position.
A special metalworking tool is required for editing. You cannot straighten it with any hammer that is at hand: the metal may not only not straighten, but also acquire even greater defects. The hammer should be made of a soft material - lead, copper, wood or rubber. In addition, you cannot straighten metal with a hammer with a square head - it will leave marks in the form of nicks on the surface of the metal. The hammer head should be round and polished.
In addition to hammers, wooden and metal smoothers and supports are used. They are used for straightening thin sheet and strip metal. For straightening hardened parts with shaped surfaces, there are correct headstocks.
It is probably not worth reminding that straightening (straightening) of metal must be done in work gloves, regardless of whether the work is complex or not, whether the workpiece is large or small, or whether it is strongly curved.
To check the curvature of the workpiece, you need to lay it on a smooth plate with the surface that should be flat after straightening. The gap between the plate and the workpiece will indicate the degree of curvature that needs to be corrected. Curved places must be marked with chalk, this makes it much easier to strike with a hammer than focusing only on the curvature noticeable to the eye.
— Metal editing
During processing, storage or operation, metal parts and workpieces may lose their original shape.
To perform subsequent operations and maintain the dimensions and shape of the finished product, it is important that the configuration and dimensions of the workpiece coincide with the design values. This is achieved by the intermediate preparatory operation of straightening the metal. The operation is carried out on a cold part or it is heated for the purpose of plasticity.
The sheet workpiece may become wrinkled, having a cylindrical shape, and become bent. Shafts and axles may become bent.
What is metal straightening?
The process of returning a metal workpiece to its original shape is called metal straightening. The defects are as follows:
- Wave.
- Dent.
- Convex.
And also some others.
Types of metal straightening
The operation is divided into two subtypes:
Manual straightening and straightening of metal is used in home workshops and in the manufacture of unique products. The set of tools is simple, but requires a highly qualified worker - a straightener.
Machine straightening is used in industry. The equipment is massive and complex, but has high productivity and process automation capabilities. In addition, the machine straightening operation is often combined with bending and cutting of sheet blanks, including it as part of a single technological complex.
The operation can be carried out at room temperature. Working at temperatures of 0C and below is unacceptable - the material loses its ductility and becomes brittle. Sometimes the workpiece has to be heated to 140-400C to increase ductility.
Sheet metal straightening
The complexity of the sheet metal straightening operation also depends on the type of defect.
The most difficult cases are a combination of different types of defects, for example, a waviness of the edge and a bulge in the center of the sheet at the same time.
Convex
The convexity is corrected by blows along the circle, starting from the outer side of the defect and gradually reducing the radius of the circle, moving from the edge to the center of the defect. The force of the blows becomes less, and the frequency increases.
If there is more than one bulge on the workpiece, they should be combined into one large one. You should hit between local defects, achieving their unification, and then act as described above.
Waviness of edges
Straightening of sheet metal with wavy edges is carried out starting from the edges of the sheet and gradually moving towards its center. After stretching the workpiece in the middle, the wavy edges are smoothed out.
Thin sheets
Small thickness workpieces cannot be straightened with strikers due to the high probability of the formation of tears and creases.
To straighten thin sheet metal, extended surfaces of metal or wooden smoothing bars are used. The workpiece is smoothed from different sides, gradually increasing the pressure.
Periodically it is necessary to turn the strip over so that there is no bulge in the other direction. If there are several bulges at the beginning, you should straighten the ends of the strip, and then move to the middle.
Soft strikers are not used for straightening. They are made from a high-strength alloy and are given a rounded shape or the sharp side is rounded.
To straighten hardened metal, blows are directed along the concave area of the part. As the material on the concave side stretches, the workpiece will straighten. The operation is carried out on a hemispherical straightening headstock, along which the part is gradually moved up and down.
To straighten a hardened square with a violation of the right angle, two techniques have been developed. If the corner has become acute, the blows are directed near the inner corner. If the angle has turned into an obtuse one, the blows are directed to the area at the top of the outer corner. The material in the affected area is stretched and the right angle is restored.
The method is similar to working with a strip. Irregularities are marked with chalk, the workpiece is positioned with the convex side up. The blows are directed from the periphery of the defect to its center.
When the main defect is corrected, reduce the impact power and rotate the part around the longitudinal axis to avoid deformation in the other direction. Square and rectangular rolled products are straightened using the same method.
The unwinding method is used here. One end of the spiral is fixed in a vice fixed to a straight plate, the other in a hand clamp.
After partial unwinding of the spiral, it is pressed against the plate and straightened like a round piece, determining the curvature in the light.
Basic methods of straightening metal
The choice of method is influenced by the nature and cross-sectional area, grade and type of alloy, and the size of the defect relative to the overall size of the product.
Depending on the method of applying stress to metal workpieces, there are three methods of straightening metal:
- cold bending;
- cold stretching;
- local heating
Heating is carried out with gas burners or induction.
For what purposes is metal straightening used?
The configuration of a part may be disrupted during its initial processing, transportation or storage. Such blanks are unsuitable for further use, but are not irrevocable, final defects. Metal straightening is used to return the workpiece to the shape determined by the design and technological documentation.
Sometimes, in order to reduce production costs, an enterprise deliberately purchases workpieces of improper shape, in which case the operation is included in the technological process. Planned straightening of metal can also be included in the technical process after heat treatment operations that cause a change in the shape of the part. Otherwise, the work will be unplanned, and its cost is included in unplanned losses.
Straightening equipment
The foundation of any tool kit is the right slab. It must be perfectly smooth, massive and stable, for which it is cast from impact-resistant cast iron or steel, and is equipped with longitudinal and transverse stiffeners to strengthen the structure. They are installed on a massive concrete base.
Straightening hammers should be softer than the workpiece material. Therefore, they are equipped with wooden or rubber strikers. To work with steel sheets, hammers with soft strikers made of copper or lead are used. The firing pin must have a rounded shape. A square-shaped striker is not suitable, as it will leave characteristic marks on the sheet workpiece - nicks. The mass of the slab should be in a ratio of approximately 100:1 to the mass of the hammer.
To work with sheet workpieces, a backing plate made of dense rubber is also used, with a large number of tubercles of the same height formed on it. Under impacts, the metal itself finds its place, and the productivity of the process increases noticeably compared to a bare steel straightening plate.
To work with thin sheets, special equipment is used - smoothers and supports. To work with hardened parts, cylindrical or hemispherical straightening heads are used.
In a home workshop, an anvil or a massive metal plate is used.
Enterprises use special mechanized leveling complexes with mechanical sheet feeding and automated correction of defects. In some, the workpiece is pulled between massive rotating rollers rotating in opposite directions. In others, the operation takes place on a regular plate by lowering a wide press.
Source: https://stroysoc.ru/calculators/sposoby-pravki-metallov-primenyaemyi-instrument-chto-takoe/
Metal straightening price
Consultation by number 4993900333
Metal straightening is a process aimed at eliminating defects and shortcomings in metal workpieces. The very essence of metal straightening basically boils down to the expansion of cavities or the compression of convex surfaces.
Editing can be carried out manually (when making unique products at home) or by machine (in an industrial environment using complex and massive equipment).
With the machine straightening method, the workpiece is passed between rollers rotating in different directions, or, when using a press, the product is placed on supports, after which the press is lowered onto it.
Editing methods
Straightening methods: - cold straightening methods, based on the principle of elongation of the fibers of the welded joint, which received plastic shortening changes during welding. These methods have become widespread because
can be carried out by piercing, rolling the welded joint area, or stretching; — straightening by stretching on special stretching machines; — straightening by piercing the area of the welded joint (used for elements with a thickness of less than 10 mm);
— thermal methods.
When using such methods, local heating of deformed elements and parts of structures is provided.
Equipment
Equipment intended for straightening metal includes: - smoothers - used for straightening strip and thin sheet metal; - hammers with a round striker - necessary in most cases, because they prevent dents and nicks on the surface of the elements being straightened; - straightening plate, which is a flat prismatic steel plate, quite massive and heavy, designed for straightening rods and metal sheets;
- hammers with inserts made of soft metals.
Products subject to processing
Products made of ductile metals, for example, steel, copper, etc., are subject to straightening. Parts or workpieces made of brittle metals are not subject to straightening.
Straightening is used for deformed metal sheets, warped or bent workpieces, shaped bars, strips, etc. to prepare them for subsequent processing and use.
Editing is also required after heat treatment, welding or soldering of elements, and cutting various blanks from sheet metal.
Source: https://pzo.ru/metalloobrabotka/pravka-metalla
Editing sheet metal - Metalworker's Handbook
During processing, storage or operation, metal parts and workpieces may lose their original shape.
Metal straightening
To perform subsequent operations and maintain the dimensions and shape of the finished product, it is important that the configuration and dimensions of the workpiece coincide with the design values. This is achieved by the intermediate preparatory operation of straightening the metal. The operation is carried out on a cold part or it is heated for the purpose of plasticity.
The sheet workpiece may become wrinkled, having a cylindrical shape, and become bent. Shafts and axles may become bent.
What is metal straightening?
The process of returning a metal workpiece to its original shape is called metal straightening. The defects are as follows:
- Wave.
- Dent.
- Convex.
And also some others.
Straightening of strip metal bent in a plane
Belongs to the category of simple ones. The strip is placed with the curved side up. The blows are directed to the most protruding areas. As the defects decrease, the impacts should be weakened.
Straightening of strip metal bent in a plane
Periodically it is necessary to turn the strip over so that there is no bulge in the other direction. If there are several bulges at the beginning, you should straighten the ends of the strip, and then move to the middle.
Editing hardened metal (straightening)
Soft strikers are not used for straightening. They are made from a high-strength alloy and are given a rounded shape or the sharp side is rounded.
Editing hardened metal (straightening)
To straighten hardened metal, blows are directed along the concave area of the part. As the material on the concave side stretches, the workpiece will straighten. The operation is carried out on a hemispherical straightening headstock, along which the part is gradually moved up and down.
To straighten a hardened square with a violation of the right angle, two techniques have been developed. If the corner has become acute, the blows are directed near the inner corner. If the angle has turned into an obtuse one, the blows are directed to the area at the top of the outer corner. The material in the affected area is stretched and the right angle is restored.
Round metal straightening
The method is similar to working with a strip. Irregularities are marked with chalk, the workpiece is positioned with the convex side up. The blows are directed from the periphery of the defect to its center.
Round metal straightening
When the main defect is corrected, reduce the impact power and rotate the part around the longitudinal axis to avoid deformation in the other direction. Square and rectangular rolled products are straightened using the same method.
Straightening metal twisted in a spiral
The unwinding method is used here. One end of the spiral is fixed in a vice fixed to a straight plate, the other in a hand clamp.
Straightening metal twisted in a spiral
After partial unwinding of the spiral, it is pressed against the plate and straightened like a round piece, determining the curvature in the light.
Quarantine in schools in 2020 in Russia may happen due to an epidemic
The period of time during which it is allowed to close school in a certain class, an entire school or throughout the city is called quarantine.
As a rule, special measures are introduced in cases where there is a high incidence of colds or other ailments spread by airborne droplets in a populated area.
The ban on visiting educational institutions can last for one day or several weeks. The end of quarantine is marked by the number of visits to the doctor. When the epidemiological threshold is lowered, the presence of schoolchildren in classes is allowed.
If up to 30% of the total number of students in a class or group are absent from school, the class teacher is obliged to contact the students’ parents. His task is to find out the reason for the decision not to go to classes and find out whether changes will be made (they are a valid reason for the child’s absence). The issue of closing a class for quarantine will be considered if 30 percent or more of the students in the class are officially ill and contact medical institutions.
Let's look at the situation clearly. Let's imagine that there are 29 students in a class. Seven students did not come to school because they would be filing for sickness certificates. In this case, the management of the educational institution makes a decision to introduce quarantine. Often the period of temporary cessation of the educational process drags on for three days or until the end of the current week. Next, the decision is made according to the situation.
Will quarantine be declared in Moscow schools?
Quarantine is a set of restrictive measures aimed at stopping the spread of the epidemic. Its main task is to minimize or isolate communication between infected persons and others in order to avoid worsening the situation. Quarantine may be declared due to the spread of influenza or ARVI. In addition, preventive measures are introduced for the following infections:
- measles.
- scarlet fever.
- chickenpox.
- diphtheria.
- rubella.
- dysentery.
- whooping cough.
- tetanus.
- similar ailments.
Domestic legislation prescribes a set of measures related to the introduction of quarantine. They are regulated by Federal Law No. 52, adopted to ensure the sanitary and epidemiological well-being of citizens of the Russian Federation in March 1999.
The decision to close a general education institution due to the incidence of ARVI is made by the Chief Sanitary Doctor of Moscow or the microdistrict in which the educational institution is located. Doctors, together with representatives of the local government, sign an order to close a school, kindergarten or university within 24 hours. Restrictive measures can be taken both in relation to the school and to individual classes.
The number of days during which the quarantine lasts will depend on the incubation period of the disease that caused the restrictive measures. In the case of influenza, it takes from 5 days to 1-1.5 months. It is true that schools are rarely closed for the maximum number of days. Often, quarantine associated with the spread of ARVI lasts up to 7 days. The faster the number of infected citizens begins to decline, the sooner the restrictive period will end.
What kind of flu will come to Russia in winter 2020 and how to recognize it
During the current cold season, according to forecasts from the World Health Organization, four strains of the virus will come to the territory of European powers, which includes Russia: Kansas, Phuket, Colorado and Brisbane. If the last one does not pose a great threat to humans, the other three belong to group “A”, and therefore pose risks to health and life.
The type of virus can only be recognized in a laboratory, because in general, the symptoms of influenza are no different from ARVI. The difference between these diseases is observed in the first period of infection. The flu makes itself known by a high temperature that does not decrease over time. In the case of acute respiratory diseases, it all begins with a cough and runny nose.
In addition, the infection does not lead to sneezing. With a dangerous illness, you will have difficulty breathing and heaviness throughout your body. But nasal congestion is not accompanied by traditional tickling in the nostrils. This feature is characteristic of ARVI. In any case, it is important to contact a medical facility in time.
Timely provision of assistance will allow you to quickly get rid of the disease and not face its unpleasant consequences.
How do restrictive measures differ from quarantine?
If dangerous symptoms are detected among participants in the educational process, one can expect the occurrence of diseases that can affect the epidemiological situation in the city. School administrators must be proactive to implement special measures or quarantines.
If appropriate measures are not taken, management will bear administrative liability in accordance with Article 6.3 of the Administrative Code. In this case, a fine of 500-1000 rubles or 10-20 thousand rubles is provided. It all depends on the degree of guilt of the director of the institution.
For this reason, it is important to understand the importance of quarantine and introduce restrictive measures in a timely manner.
- Measures to limit the educational process are a list of steps that school management takes to reduce the likelihood of infectious diseases or other ailments of another nature. The list of special measures includes the cancellation of classes, the postponement of events, as well as other changes to the rules of stay in an educational institution.
- Quarantine is a complex of medical, sanitary, administrative, and other measures that make changes to the educational process. Within its framework, the closure of classrooms, groups or entire institutions, the transition to distance learning, or the regular holding of medical facilities may be carried out.
Source: https://pronedra.ru/karantin-v-shkolax-2020-goda-v-rossii-mozhet-sluchitsya-iz-za-epidemii-443281.html
Metal straightening: types, equipment, methods of straightening at home | mk-soyuz.rf
Metal straightening is the process of eliminating irregularities on the surface of a material. The operation applies to both blanks and finished parts. The main reasons: the shape of the product does not correspond to the specified parameters, as a result of convexity, curvature or warping. Editing the material is possible at home.
Straightening sheet metal is one of the simplest operations. It is carried out to bend thin material. To do this, the sheet is placed on a plate or anvil. The amount of curvature is determined by the gap between the metal and the cast iron plate.
The hammer strikes the convex part of the surface. To prevent the material from bending in the opposite direction, the sheet is constantly turned over. As the curvature decreases, the force of the impacts decreases.
If there are several irregularities, the lateral defects are eliminated first, and then the central curvature.
Metal straightening and bending
Tools in use must meet the following conditions.
- 1. The working surface of a wooden hammer must have a smooth, even surface, without cracks or chips. Hammers must be made of hardwood (birch, beech, maple, oak) and not have knots.
- 2. Correct slabs with a smooth and level working surface must be installed on a solid base.
During work, special attention must be paid to installing and securing round and flat mandrels in the vice, as they can break out of the vice and cause bruises on the hands and feet. To protect your hands from damage when editing, you should wear gloves.
General concept of metal straightening
The blanks made from strip, rod or sheet material received by a mechanic are often bent, crooked or warped. Eliminating these defects in workpieces is called straightening.
Thus, editing is primarily a preparatory work (operation).
Metal straightening can be done by machine (on straightening rolls, presses and all kinds of devices) or manually, performed with a metalworker’s hammer on a steel or cast iron plate or anvil. When straightening by hand, it is better to use a hammer with a round rather than a square head.
As with chopping, the hammer must be held by the end of the handle, fig. 5.1. Strikes should be applied only with the convex part of the striker. Impacts from the edge of the striker leave deep nicks on the surface of the straightened part.
To edit, you need to take a hammer with a smooth and well-polished striker surface.
Rice. 5.1. Holding a hammer and striking while straightening
Straightening is done with a steel hammer. Only for straightening parts with a treated surface, as well as thin steel products or parts made of non-ferrous metals and alloys, hammers made of soft materials - copper, brass, lead, wood - are used. When straightening particularly thin metal, metal and wooden smoothing bars are used.
Sometimes the treated surface is also straightened with a steel hammer. In these cases, a non-ferrous metal gasket is placed on the straightened product and blows are applied to it.
Cast iron parts are not subject to editing.
Source: https://studref.com/560677/tehnika/pravka_gibka_metalla
Straightening and straightening of metal; essence and purpose of straightening and straightening
HOME FITTERS
Straightening and straightening are operations for straightening metal, workpieces and parts. Sheet material and blanks made from it can be warped at the edges and in the middle, have bends and local irregularities in the form of dents and bulges of various shapes. When examining deformed workpieces, you can notice that their concave side is shorter than the convex side. The fibers on the convex side are stretched, and on the concave side they are compressed.
Straightening and straightening have the same purpose, but differ in the methods of execution and the tools and devices used.
Straightening is the straightening of metal by applying pressure to one or another part of it, regardless of whether this pressure is applied by a press or by hammer blows.
Straightening should be understood as straightening the metal by stretching, i.e., elongating one or another part of it. Straightening is usually performed by blows with the toe of a hammer or a special straightening hammer with sharp strikers. After straightening, clearly visible hammer marks remain on the workpiece or part; This doesn't happen when editing.
Editing is, as a rule, a preparatory operation preceding the main metal processing operations. Steel sheets and sheets of non-ferrous metals and their alloys, strips* rod material, pipes, wire, as well as metal welded structures are subject to straightening. Workpieces and parts made of fragile materials (cast iron, bronze, etc.) cannot be straightened.
There are two methods of straightening metals: manual straightening, performed with a hammer on steel or cast iron straightening plates, anvils, etc., and machine straightening, performed on straightening machines. When manually straightening, the mechanic looks for places on the surface of the workpiece or part that, if struck, would straighten the workpiece, that is, lie on the plate without bulges, bends or waviness.
The metal is straightened both in cold and heated states. In the latter case, you need to keep in mind that straightening steel blanks and parts can be done in the temperature range 1100-850°, and duralumin - 470-350°. Heating above these temperatures leads to overheating, and then to burnout of the workpieces, i.e. to an irreparable marriage. The choice of method depends on the amount of deflection, size and material of the product.
So, you have purchased a massive board to cover the floor, now you should familiarize yourself with the methods of laying it on the floor. After all, a properly laid solid board will provide you with a beautiful and reliable floor for a long time.
Bathroom for a child. Make a fairy tale with your own hands
What should a child's bathroom be like? First of all, safe, interesting and original. You should be guided by this when choosing not only furniture and accessories, but also plumbing fixtures for the children's bathroom.
What to pay attention to when decorating a kitchen?
What to pay attention to when decorating a kitchen? The usual kitchen environment can become boring. Then the desire to change it appears. For this purpose, Kyiv kitchens are purchased, but there is not enough furniture. It is necessary to properly design the window, select
Source: https://msd.com.ua/domashnij-slesar/pravka-i-rixtovka-metalla-sushhnost-i-naznachenie-pravki-i-rixtovki/
Metal straightening
During processing, storage or operation, metal parts and workpieces may lose their original shape.
Metal straightening
To perform subsequent operations and maintain the dimensions and shape of the finished product, it is important that the configuration and dimensions of the workpiece coincide with the design values. This is achieved by the intermediate preparatory operation of straightening the metal. The operation is carried out on a cold part or it is heated for the purpose of plasticity.
The sheet workpiece may become wrinkled, having a cylindrical shape, and become bent. Shafts and axles may become bent.
What is metal straightening?
The process of returning a metal workpiece to its original shape is called metal straightening. The defects are as follows:
- Wave.
- Dent.
- Convex.
And also some others.
Any trained person is a magician
Material from Posmotre.li
Exactly what it says on the package. The ability to use magic does not require any innate or gifted gift. Any individual who has undergone training is capable of casting spells. Efficiency depends only on how diligently the wizard studies. Simply put, it's like fencing - anyone can do it, but how well depends on training and experience.
However, some options are possible:
- 1. There is no such thing as a magical gift; it all comes down to study and training.
- 2. There is a gift, and its owners are an order of magnitude stronger than those who are not gifted. But even those who do not have a gift can learn magic.
- 3. The gift is there and provides certain advantages, but learning is more important. A well-trained non-gifted magician is stronger than a gifted ignoramus.
- 4. There is a gift, but it is required only for mastering certain types of magic.
NB: please indicate the most unusual examples.
- 1 Examples
- 1.1 Literature
- 1.2 games
- 1.3 Board games
Examples[edit]
| Yes, it happened a million times! The author of this article is sure that he has seen examples of this trope many times, but cannot remember enough of them. Maybe at least a couple more come to mind? |
The development of magic in various magical institutions. Thousands of them.
Literature[edit]
- “The Chronicles of Echo” by M. Fry - all inhabitants of the world of Echo are capable of magic, and the inhabitants of the city of Echo use it literally from the cradle. Going beyond the boundaries of everyday magic requires both talent and training.
- T. Goodkind, “The Sword of Truth” - options 3 and 4.
Any person can master Increment Magic, and at a fairly high level (much beyond the capabilities of an untrained magician with the Gift). But a trained owner of the Gift is incomparably stronger. It is worth considering, however, that the Gift is a complex thing, and in the absence of training, it is 100% likely to kill its bearer.
But Damage Magic is available only as an innate ability, although options are possible.
- Dyachenko, “Magics can do anything” is a pure second option. Magicians are divided into innate and learned, and the innate are much stronger than the learned, but they are in no way capable of developing their gift and learning new things.
- Anton Orlov, “Tina Hadis” - in the last books of the series it turns out exactly like this. Even two former “liquidators” of the Ygrek Office, which was engaged in the destruction of all carriers of supernatural abilities, become powerful psionics.
games[edit]
- Dungeon Siege 2 - Archers can “enchant” a bow/crossbow to deal lightning damage. Swordsmen can become enraged, causing elemental damage.
- Dungeon Siege 3 - Lucas, an ordinary warrior can, at a minimum, heal himself and others. A pure warrior, what can I say.
- Pillars of Eternity - with a wick, but the monk is suitable. A regular fighting class that can summon its counterparts.
Show everyone your personality disorder
- Suspiciously reminiscent of Storm, earth and fire from WoW. Isn't it a copycat?
- Path of Exile - any character can place a spell stone in the appropriate slot on their equipment and cast it, the only question is efficiency.
- Minecraft - a pumped-up villager starts trading enchanted goods.
Board games[edit]
- D&D - Wizards study magic as a science, cast spells from Intelligence, have the most extensive arsenal of spells, and look down on Sorcerers, who receive magic simply from birth or as a result of contact with a magical anomaly.
- In general, it can be said that many classes in D&D learn their magic almost from scratch, such as artificer inventors, bards, and rangers. Paladins and priests play out this trope in a zigzag manner - on the one hand, you can learn how to do sacred rituals and spells, on the other hand, this is still the magic of the gods, bestowed from above.
- Multiclass allows a warrior to take the level of a mage to be able to use scrolls of high-level spells
Source: https://posmotre.li/%D0%9B%D1%8E%D0%B1%D0%BE%D0%B9_%D1%82%D1%80%D0%B5%D0%BD%D0%B8 %D1%80%D0%BE%D0%B2%D0%B0%D0%BD%D0%BD%D1%8B%D0%B9_%E2%80%94_%D0%BC%D0%B0%D0%B3
