Bending a profile pipe with your own hands without a pipe bender. How to bend a profile for a greenhouse with your own hands? Profile pipe bending: how to do it correctly

The question often arises of how to bend a profile pipe without a pipe bender? It is known that the implementation of various construction or repair work on a suburban area involves the widespread use of profiled pipes.

The use of this type of rental has a number of advantages:

It has great strength at a relatively low weight.
The profile pipe can be used for the installation of any structures from a greenhouse to various sheds, gazebos or verandas.
The possibility of processing by welding or various types of hand tools allows you to do most of the work yourself.
The construction, assembled from a square profile, will look much more attractive than its counterpart from a traditional round pipe.

If there is a desire to make an arched structure to decorate a gazebo or install a greenhouse, you will have to bend it manually or resort to the help of specialists.

Main features of bending technology

It is necessary to clearly understand the processes that occur in the metal during its controlled deformation. The main goal in this case is to obtain a uniformly curved shape without violating the integrity of the rolling profile. To correctly bend a pipe of any cross-sectional shape, two methods are used:

flexion under the influence of external force;
combination of pressure and local heating in the bend section.

In both cases, the following processes occur simultaneously - the material of the outer layer of the arc will stretch, and the inner layer will shrink. As a result of bending, a significant excess of the load can lead to cracks and destruction of the outer wall of the pipe. The inner surface can lose its smoothness, while well-visible metal folds are formed. Violation of the process technology can also cause distortion of the pipe walls or dislocate their alignment. Such a phenomenon will have an extremely negative effect on the aesthetics of the resulting arch and will cause its forced rejection.

There are other parameters to consider as well. The radius of the desired curvature, the wall thickness of the workpiece, its material and cross-sectional dimensions will be of great importance.

The industry produces shaped pipes that have a square, rectangular, oval, flat-oval or round cross-section. The use of square and rectangular products during construction work has its advantages. Such pipes are much more convenient when performing installation work. They simplify the marking, joining and fitting of structural elements with each other. It is much easier to attach various coatings to a flat surface of such a profile or combine them with other materials.

Methods of cold bending of pipes: a - with running-in; b - winding; c - by dragging; d - rolling; d - on two supports; e - stretching; g-with internal hydrostatic pressure; and - through a die having a curved axis; k - by copiers.

Pay particular attention to the section height. This indicator determines the plastic parameters of a particular grade of rolling material. Based on its value, the maximum possible bending is calculated. Let us denote the height by the letter h. Then, with a size of up to 20 mm, it is possible to bend the pipe without destruction in a section of 2.5 × h and more. In cases where h> 20 mm, the formula is: 3.5 × h or more. Violation of this rule will lead to cracking or general warping of the metal.

The thickness of the profile walls must be taken into account. If it does not exceed 2 mm, it is impractical to bend the material. In such cases, welding has to be used. Thicker walls lend themselves to bending, but the increase in thickness makes it much more difficult.

The material of the rolled profile can also have an effect on the process. Low-alloy and carbon steel pipes have significant elasticity. Such material, after removing the external load, tends to restore its previous shape. This will require re-machining until the required arch radius is maintained. Copper pipes do not have this disadvantage. Due to the high ductility of the material, they easily change shape and retain their altered state after removing the load.

Profile bending methods and sequence of their execution

The choice of bending method depends primarily on the size of the cross section and the available tools and equipment. Usually small materials are cold bent. Such pipes have sufficient ductility and amenable to controlled deformation with low external forces. For a large profile, heating is usually necessary. Exposure to temperature significantly increases ductility and reduces the required amount of applied pressure.

For pipes with circular cross-section, heat treatment is used with a diameter of 100 mm and more. For square and rectangular products, the calculation takes into account the cut height. If the profile height is up to 10 mm, heating is not applied. With a height of 10 to 40 mm, the processing method is selected based on the experience and capabilities of the performer. When the size exceeds 40 mm, local heating is necessary.

The presence of a pipe bender allows the manufacture of arched structures without additional heat treatment. In cases where machining is not possible, test bending should be performed. The profile is clamped in a vice, a larger diameter pipe is put on its protruding end, which is used as a lever for the applied force. No heating is required.

Bending with local heating

The technology of such processing involves filling the pipe with sand. Its presence in the inner cavity of the product guarantees the quality of workmanship and the uniformity of the arch.

Initially, you need to prepare two wooden plugs. They must be pyramidal in order to seal tightly. The length of the plugs should be 10 times the profile width. After manufacturing, the plugs are tried on to the pipe holes, while checking the tightness. Further, on one of the plugs, sawed longitudinal grooves on the side surfaces. Their presence is necessary for the discharge of overheated air from the pipe during heat treatment. The place of the future bending of the product is determined and the preheating of the metal is performed.

After that, they begin to prepare the sand. It is best to use dry and clean medium grit material. It is successively sieved through sieves with meshes of 2, and then 0.7 mm. This removes large impurities that can cause a bumpy surface and dust that can sinter inside the pipe. The filler is heated to a temperature of 150 ° C.

We hammer a cork into the pipe, which does not have longitudinal cuts, and pour the prepared sand through the funnel. When backfilling, it is necessary to tap with a wooden mallet on the walls of the profile to ensure the compaction of the material. After the final filling, the second plug is installed and tightly clogged.

The fully prepared pipe is positioned in a vise or pipe clamp next to the template. If there is a pipe seam, it must be positioned on the side of the arch. The area marked with chalk is heated with a blowtorch to a red color and bends in one smooth, unsharp movement. The resulting arch is compared with a template, after which the plugs are removed, and the filler is emptied. It must be remembered that repeated heating is extremely undesirable, since it significantly reduces the strength of the material.

Bending without heating

The question of how to bend profile pipes without a pipe bender can be solved without temperature exposure. The use of the filler depends on the dimensions of the section. If its height does not exceed 10 mm, no sand is needed. For large sizes, the use of bulk material is highly desirable. Alternatively, it is possible to use a steel spring made of wire with a diameter of at least 2 mm. It is preliminarily placed in the place of the future bend to give it a smooth uniform contour. The technology of the process itself completely coincides with the hot method, with the exception of heating the metal.

The use of manual pipe benders or specialized machine tools during the bending process of profiled metal greatly speeds up and facilitates the process.

The work of professionals guarantees the high accuracy of the contour and its quality. But if the possibility of attracting them is not available, it must be remembered that this work can be done independently, while significantly reducing your costs.

Bending a profile pipe is just the case when you simply cannot cope with the task without a special tool. Despite the seemingly not too strong structure, a profile pipe (rectangular or square), even with a small wall thickness, is able to withstand significant loads without deformation.

That is why it is often used as a frame for various lightweight structures. But if, out of necessity, you have a need to give a shaped pipe a curved shape, you should know how to bend it correctly without damage.

Profile pipe-rolling, in contrast to round, differs in cross-sectional shape, which can be of several types:

square;
flat oval;
rectangular;
oval.

According to the regulations of GOST R 54157-2010, the list of profile products should also include a round pipe. However, for the construction of greenhouses, it is the square shape that is more often used, since it is easier to attach a covering to it.

Today pipe-rolling products are produced in a wide range. It differs in cross-sectional area, configuration and wall thickness. That is, in relation to the bending of the pipes, the minimum radius of curvature is called. First, you need to determine the minimum radius of a flat round deformation. Otherwise, the workpiece will not survive the bending and will be damaged.

So, to determine the smallest permissible bending radius of a rectangular or square pipe, you should know the height (h) of the profile, since:

rolled pipes with a height of more than 2 cm are able to withstand without loss of deformation in a section with a length of 3.5 × h and more;
pipe-rolling up to 2 cm in height is able to withstand without loss of deformation on a section with a length of 2.5 × h and more.

Based on these limits, you can begin to design the process of manufacturing shelves, racks, frames for vents, windows and doors, as well as other products from a profile pipe. Also, some adjustments are made by the thickness of the walls.

If the wall thickness of a wide pipe is less than 2 mm, then it is generally not recommended to bend it. In this case, it is preferable to use welding.

If you decide to make a greenhouse from conventional low-carbon and carbon steel alloys, then they tend to slightly "spring", that is, return to their original position. Therefore, before installation work, each arched arch will need to be double-checked and, if necessary, bend over a template.

Bending methods

The profile pipe can be bent either manually (using a manual pipe bender) or using a special machine. You can choose a method based on the following main points:

if you need to bend a small number of profile pipes (from 1 to 5), then it is easier to do it manually;
with large pipe cross-sections and significant wall thicknesses, you will have to use a profile bending machine;
a small radius of curvature can be performed both manually and using a machine.

If you do not consider yourself a person with significant physical strength even when using a long lever to strengthen it, then you better not consider the option with a manual pipe bender.

In addition, if you are not going to bend pipes all the time, then buying any special tool for these purposes will be financially unprofitable for you. As a way out of this situation, you can:

seek help from the nearest workshop dealing with similar work;
make a machine for bending shaped pipes yourself from scrap materials;
use the method of bending pipes using a "grinder" and welding.

Here we describe 2 methods of bending: heat and cold.

Before you begin to deform the material by heating, fill its cavity with sand. This will significantly increase the quality of processing, for example, the fold will be even.

For work, be sure to use tarpaulin gloves.

So, the work process is as follows:

Use a piece of wood to make 2 pyramidal plugs. Their length should be 10 times the base of the width. As for the base area of the plug, it should be 2 times the opening of the square or rectangular pipe.
Next, try on the caps on the pipe. On one of them, it is necessary to make grooves so that gases can escape from the pipe during heating.
Immediately before the folding process, the workpiece must be fired.
Now you need to fill the inside of the pipe with medium grain sand. In its composition, pebbles and gravel should be completely excluded. To do this, sift all the sand. If there are large fractions in the sand, they can contribute to the formation of an irregular bend relief. For this reason, the sand should be sieved through a sieve with a mesh size of 0.7 mm. If dusty particles remain, then when the pipe is heated, they will sinter inside.
After cleaning the sand, calcine the whole mass at a temperature of 150 ° C.
After that, plug one end of the pipe with a plug, on which there are no channels for exhausting gases. Install a funnel on the other side of the pipe and pour sand through it in portions. Tap the pipe walls periodically so that the filler can seal well. If the sound when hitting a wooden mallet is empty, it means that the pipe is well filled.

Close the pipe with a stopper.
The place to be bent should be marked with chalk.
Now clamp the pipe with a template in a vice. If the pipe has a weld, then place it on the side. Stretching along the seam is not recommended.
Heat the marked area red-hot, and then carefully give the pipe the required shape. Bend should be in one step with translational movements.
When the workpiece has cooled down, compare it to the template. If everything is the same and you do not need to repeat the procedure, then you can burn out the corks and pour out the sand.

In this work, one must not fuss and rush. Excessive movement can bend the workpiece. Moreover, it is important to observe safety precautions, because you will have to work at high temperatures.

It is not worth heating the pipes several times. Under the influence of a temperature shock, the material simply loses its strength, worst of all, it can burst when it is heated again to 800 ° C. Therefore, everything should be done the first time. In this case, you will be able to make the necessary blanks for the construction of a greenhouse.

It is possible to deform the pipe without resorting to heating. The cold folding process can be performed with or without filler. For example, if the material has a profile height of up to 1 cm, then the filler is not needed. If the pipe is thick, then it is necessary to fill it with sand. Can also be filled with rosin.

A good alternative is a spring that fits directly into the bend area. Due to the spring, the material at the bend points will be protected from a sharp change in the profile section. This article discusses several techniques on how to cold bend a profile pipe.

Without pipe bender

As already mentioned, you can use a spring, as well as a blowtorch complete with it. For this it is necessary to prepare a steel wire Ø2 mm. You make a spring from it so that it can fit tightly inside the pipe. Alternatively, you can buy a ready-made spring designed for bending pipes.

So, the spring is inserted into the marked place and heated with a blowtorch.

By such a device is meant several types of devices that allow you to bend a pipe with different cross-sections for greenhouses, sheds, home greenhouses and other structures where metal frame elements are used. Tube benders are classified into two types:

Roller. Very often it is called - profile bender. It is used to bend the pipe along smooth radii. Bending takes place according to the principle of pipe rolling.
Hydraulic lever arm. This technique will also allow the pipe to bend to the desired angle. Bending pipes is easy thanks to the special lever.

In general, the use of a pipe bender has a number of advantages, here are some of them:

Less labor is involved. When using a device with an electric drive, efforts are generally reduced to zero.
There is no need to weld or use additional fittings.
Due to the observance of the bending technology, the pipe retains its technical characteristics and kinks and flattening are prevented.
Finished products get a perfectly precise shape.

The most difficult thing is to choose the right machine. The choice may depend on the pipes used, namely the material from which they are made. For example, if it is necessary to bend a copper pipe, then it is sufficient to use a manual pipe bender. But if we talk about a profile pipe, then it is best to use a roller pipe bender to bend it.

A manual pipe bender is a device that allows you to bend a pipe of a certain section using physical force. The pipe bender allows you to fix the bendable pipe to facilitate all the work, as well as to select the required bend radius, focusing on the templates included in its kit.

Due to the rather high physical complexity of working on a manual pipe bender, it is usually used only to create single bent shaped pipes.

One of the demanded profile benders is the manual machine "PG-1" and "PG-2". The first option is a fairly mobile device. This allows the folding process to be carried out directly on site. It can bend pipes 40 × 40 mm in size. By its design, the equipment has a frame and 3 rollers, which are fixed on it. The central one, and it is the pressure roller, pulls the pipe. The comfortable handle allows the process of work to be carried out quite easily.

As for the other model "PG-2", its design is more powerful. This machine can bend pipes 30 × 60 mm. If necessary, this machine can bend the pipe into a ring.

Bending machine

A special machine that allows you to bend pipes without applying significant forces is called a profile bending machine. Its only drawback is its high cost, so it is usually used in work by those who have to bend pipes quite often.

Using the machine, you can get any bending radius of a profile pipe without its destruction and deformation.

Bending occurs gradually and in stages, each time at a small bending angle, which prevents the appearance of corrugated areas, which are almost impossible to eliminate. The absence of jerks in operation when using this type of equipment allows the surface of the pipe to remain smooth, since the compression of one side and the extension of the other occurs simultaneously and very slowly.

To improve the quality of the work performed, it is recommended to additionally use the method of bending a profile pipe completely filled with liquid. The hydrostatic pressure appearing in this case prevents the pipe walls from deforming during bending. To prevent liquid from spilling out of the pipe, special plugs are put on its ends. In this case, you should be very careful to ensure that the pipe is completely filled with liquid, without air bubbles. In addition, bending of such a pipe should be started strictly in the center, and not at the edges.

"Bulgarian" and welding

If you need to bend one profile pipe with thick walls and a large cross-sectional size, then you can use a "grinder" and a welding machine for these purposes:

First of all, you need to accurately determine the required bend radius by making a template from wood.
Then, every 5-10 centimeters along the length of the pipe, make cuts on its three sides with a "grinder", leaving the same side of the pipe intact.
After that, the pipe must be applied to the template and gently and evenly bent to the required shape.
Then you just have to use the welding machine and weld all the cuts made, again giving the pipe integrity.
Once you have finished welding, you will need to sand the seams and coat the pipe with a protective coat of paint to prevent rust damage.

Since it will not be possible to quickly bend a profile pipe using this technology, besides, skills are required to work with a "grinder" and a welding machine, this method is rarely used and only for single structures.

If you are building or renovating your home, you may be faced with the need to bend various metal structures. Arrangement of an arch for grapes or a greenhouse will not do without bending a profile pipe. This is not the easiest and easiest thing to do. After all, the pipe can not only deform, it can simply crack, and in the worst case, flattening will occur. You will either have to do the welding or just get rid of this pipe.

Bending technologies for shaped pipes

There are several basic technologies for performing deformations. Let's consider each of them:

use of a profile bending machine;
the use of a pipe bender;
the use of folk methods.

The application of a spring is somewhat similar to the method with water. It is specially compressed by winding it, for example, on a metal or wooden rod, and inserted into the pipe. The thickness of the wire from which you will make the spring should be about 2-4 mm. Just keep in mind that you will have to extract it later. They take a lamp for soldering and carefully warm up the required area, then quickly begin to bend. In this case, it is advisable to use some kind of stop (template) of suitable sizes. After reaching the desired state, the pipes wait for it to cool and, if possible, remove the wire. So you reduce the likelihood of accompanying deformations, avoid cracks, accordions and other undesirable processes on the pipe.

Folk craftsmen successfully use an unusual method to bend a square pipe. At one end, the pipe is sealed, filled with ordinary tap water, taken out into the cold, or pushed into the freezer (if dimensions permit). After complete curing, the product is carefully shaped into the desired shape. This technology is suitable for copper, brass and duralumin pipes.

And the last, eco-friendly way of giving the product the desired shape is associated with bending with sand and salt. As you know, they are used for deep warming up with bronchitis, inflammation of the joints. These substances have the property of long-term preservation of their heat and are characterized by infrared radiation. If you took sand, then it needs to be well prepared: rinse, sift, remove impurities. This way you will avoid incidents. The pipe is sealed on one side, using a wooden block, and filled with heated sand. You can heat it up in a frying pan, you can use a blowtorch or in any other way. The pipe is closed on the other side and again, using a suitable template, the product is deformed to the desired angle. If something does not work out, heat the pipe with sand with a lamp. The action of this substance is similar to other fillers. This softens the pressure, and the product takes the desired shape with less loss.

As you can see, there are a lot of ways to bend a profile pipe. Moreover, it is absolutely not necessary to use expensive equipment.

If you are starting a renovation, then you may need pipes. But not always in this case, they should be perfectly even. This raises the question of how to bend a pipe without a pipe bender. If you are familiar with the tricks of this process, then you can solve the problem quite simply.

How to bend a pipe at a right angle

Metal acts as a fairly strong material, but with special exposure it can be bent. To date, there are several ways to address this issue. The first technology is the use of pegs. But you must remember that this method can damage the pipe or even break it. This can be avoided by filling the inner cavity with dry sand. Plugs must be installed at both ends.

The next step is to start flexing. For this, pegs are dug into the ground. You will use them as leverage. If you are not confident in your abilities, then first you should practice on unnecessary pipe sections. If you are faced with the question of how to bend a pipe without a pipe bender, then using this technology you can change the shape of a product, the diameter of which varies from 16 to 20 mm. For pipes of a more impressive diameter, this technique is not suitable, since the process will be rather complicated. It is also important to take into account the underlying material. For example, other methods are recommended for galvanizing.

Using heating technology

Before bending a pipe without a pipe bender, you should think about which technology is best for this. Heating may be a great solution. This method is commonly used for steel and aluminum piping. For the procedure, the product is fixed in a vise, but first it must be filled and heated with a gas burner to the place that you plan to bend. The temperature is determined quite simply: when a piece of paper approaches the pipe, it should start to smoke. When a steel billet is used, it should turn red when heated. For safety, the technician should wear gloves.

Plane-parallel plate

If you are faced with the task of how to bend a pipe without a pipe bender, you can use a plane-parallel plate. This technique involves fixing the product in a clamp. After that, you can bend, and this must be done along the plate. This technique is considered not only economical but also simple. In order to achieve a positive result, several plates should be used, each of which has a different curvature. The main condition is the use of a steel pipe. The length of the product should be quite impressive.

Using a metal spring

Quite often, home craftsmen think about the question of how to bend a pipe without a pipe bender at home. A metal spring can be used for this. This technique is excellent for non-ferrous pipes, which have good ductility.

A spring is used to prevent deformation. To obtain a good result, the size of the spring must be taken into account, which must correspond to the inner diameter of the metal structure. This requirement is due to the fact that the pipe is to be inserted into the cavity. Bending can then be performed by tying the spring with a wire to make it easier to retrieve it later.

If you need to bend a profile pipe without a pipe bender, water can be used as a filler instead of sand. The pipe cavity is filled, after which the product is sealed with plugs on both sides. The water should be frozen, and then the material should be heated. However, this method cannot be used for galvanized workpieces.

Profile pipe and its modification

This type of metal structure is quite popular when building greenhouses and gazebos on a personal plot. The main feature of the building material is that it can be damaged when bent. A way out of this situation can be filling the inner cavity with fine sand or water. These actions eliminate the possibility of damage to the pipe and achieve an excellent result. This technique is suitable for brass and duralumin piping.

If you are thinking about the question of how to bend a pipe without a pipe bender for a canopy, then you can use it for this. It is used for square shaped products. The pipeline is installed on reliable supports, and then a mallet is used. Actions must be accurate and smooth to eliminate the possibility of damage. If it is necessary to achieve a large angle, then to facilitate the process, it is necessary to heat the pipe in the place where it should be bent.

Methods of bending metal-plastic

Quite often, owners of suburban real estate ask themselves how to bend a pipe themselves without a pipe bender. When metal-plastic is available, you can use your own strengths without using available tools. The product is clamped and bent smoothly. In this case, it is important to exclude the likelihood of an inflection. It is important to be guided by the rules, which state that for every 2 cm of the workpiece, the bending angle can be 15 °.

If you are faced with the question of how to bend a pipe without a pipe bender for a greenhouse, then you can use pieces of wire that fill the inner cavity. This allows you to achieve an even and smooth bend in the shortest possible time. Dry fine sand can be used as a filler. It is poured inside, and the edges are closed with plugs. Then one end of the product must be fixed, ensuring the reliability and strength of the fastening. Use a gas torch or blowtorch to heat the fold. The material is checked for readiness with a piece of paper.

Polypropylene pipe bending methods

If you want to change the direction of the bend, you can use one of two possible methods. The first involves heating the fold. For this, a construction hairdryer is usually used. The optimum heating temperature is 150 ° C. Hands should be protected with gloves that are resistant to high temperatures.

At the final stage, the product is bent to the required shape. The thickened wall should be located on the outside of the bend. Once the material has cooled, it will need to be checked for cracks and dents. Another way to bend such a pipe is cold. However, the bending radius should not be more than 8 diameters, otherwise the product may break.

How to bend a plastic pipe

In order to bend a PVC pipe, you need to buy fiberboard. From them, you can build a frame, which is needed to give the structure a certain shape. As soon as you give the plate the desired shape, it should be sanded, it is better to use fine sandpaper for this.

The next step is to form a silicone shell for the plastic blank. It will act as a fastener for the PVC structure in the frame. In addition, it will play a protective role against chips, mechanical damage and scratches. The object is placed in a prepared protective shell, and then the place of bending is heated. The plastic softens and sits on the frame. Doing so will produce the desired shape of the plastic blank. The product is left until it cools down. This will take 15 minutes. After that, the PVC pipe can be removed from the frame, leaving it to cool completely.

If you are faced with the question of how to bend an aluminum pipe without a pipe bender, then you can use a grinder to carry out the work, with which several thin cuts must be made at the place of the intended bend. The product is preliminarily clamped in a vice. As soon as the cuts are made, they should be cleaned of chips, only after that you can begin to bend the pipe.

Sometimes the product needs to be bent in a circle. As soon as the ring closes, the holes are welded, and some craftsmen even use a soldering iron for this. In order to make the place of the fold neat, it is additionally sanded and covered with a protective agent. This eliminates corrosion and premature destruction of the joint.

Conclusion

It doesn't matter what material the pipe is based on. A perfect bend is difficult to achieve. But if you first familiarize yourself with the theory, then it will be possible to bend the pipe even without a pipe bender.

The greenhouse frame with a square or rectangular cross-section attracts with its reliability and durability. A very strong metal structure allows maximum light to pass through, because its racks, supports, ties are much thinner than those of wooden rivals. The metal is inferior in manufacturability. Without knowing the nuances, it is difficult to make an arched arc or frame for a door from a straight blank. Because of these complications with a metal base, it is in vain that they prefer to buy "green houses". However, if you thoroughly figure out how to bend a profile pipe for a greenhouse, you can build an inexpensive arched structure with your own hands at low cost.

The essence and problems of bending profile pipe

The bending of metal products, regardless of the cross-sectional shape, consists in giving them a partial or full smoothly curved configuration. One of the most common locksmithing procedures is performed either under pressure alone or under pressure in combination with heating the bent section. At this time, compressive forces from the inner side of the workpiece and tensile forces along the outer wall act simultaneously on the machined part of the hollow metal workpiece. Complications are that:

the material in the process of changing the shape may lose the coaxiality of the segments, i.e. parts of the bent workpiece will not be located in a single plane;
the stretched outer wall in the bending section may not withstand the impact and it is corny to burst;
the compressible inner wall may, instead of being uniformly contracted, fold into corrugation-like folds.

Without knowing the intricacies of profile bending, there is a risk of simply crushing the product, ruining the workpiece. But recklessness is not our way! Moreover, if it is accompanied by material losses. For the glory of rational economy, we will take into account all the vagaries of the profile and characteristics of the "iron" material. Let's not forget about the cross-sectional dimensions, the wall thickness of the profile pipe, the required bend radius and the elasticity of the steel alloy. Focusing on the specified parameters, we will choose the correct technological path - it is also a bending method.

Why do you need to know profile characteristics?

Profile pipe-rolling differs from the standard round version in the shape of the section, which can be square, oval, rectangular or flat-oval. According to the regulations of GOST R under the number 54157-2010, a round product is also included in the list of profile products. However, in greenhouse construction, products with a square and rectangular cross-section are most often used, for example, profile pipes 40x20 mm, because it is easier to attach a coating to their even flat walls.

For various national economic needs, products are produced in a wide range of sizes. It differs in configuration and cross-sectional area and, naturally, in wall thickness. The set of sizes determines the plastic possibilities. In professional language, they are called the minimum permissible radius of curvature. So, before you know how to make a workpiece for the frame, you need to find out what the smallest radius of flat round deformation the workpiece can "survive" without damage.

To determine the minimum allowable bend radius of a square or rectangular profile, we need the height h, because:

products with a profile height of up to 20 mm will be bent without passing into the category of unsuitable marriage, if the bending is performed on a section with a length of 2.5 × h or more;
rolled pipes with a profile height of over 20 mm will withstand deformation without loss in a section with a length of 3.5 × h and more.

The indicated limits are necessary for those who conceived to make racks, shelves and frames for vents or doors. The wall thickness also makes adjustments to the area of limitations. Wide pipes with thin walls up to 2mm thick are generally not recommended to bend. Better to use welding.

Home craftsmen, who decide to make arcs for, need to take into account that products used in everyday life made of ordinary carbon or low-alloy steel alloys tend to "spring" slightly after applying efforts to them. They seem to be trying to return to their previous state. Therefore, after a novice locksmith with his own hands completes the bending of all arcs, he will have to repeat the processing and re-fit the arches according to the template. It is desirable to initially take into account the value of the plastic moment of resistance Wp. It is usually indicated in the documents of the building material sold. The smaller the moment, the less fiddling with fitting.

Bending methods and their features

Profile pipe-roll is bent both in cold and hot condition. Heating with a gas burner will noticeably increase the ductility. However, a material with a small cross-section bends excellently without unnecessary temperature effects, because thin pipes are quite plastic and more easily amenable to the force applied to them.

There are no precise guidelines for using heat for bending. The standards indicate only the dimensions of the round bars, according to which the flame must be exposed to the treated area at Ø 100 mm or more. With square and rectangular shapes, everything happens a little differently. Based on the experience of craftsmen:

at a profile height of up to 10 mm, the workpieces are unambiguously cold-bent;
with a profile height of 40 mm or more, pipes are bent with heating.

How simpler and easier it is to bend a profile with a height in the range from 10 to 40 mm at home, the performer will have to decide on his own. If there is a profile bending in the arsenal of the master, with its help you can create an arched rounding without heating. There is no apparatus, it is better to test your strength in advance. To do this, you need to clamp one end of the material in a vice. On the other end, put on a pipe larger than the profile height, and pull on the "shoulder" enlarged in this way. If it works out, there is no point in heating metal products.

Option # 1 - bending with heating

We will deform the non-yielding material by the hot method, having previously filled it with sand. So the quality of processing will increase, and the uniformity of the fold will be ensured. We'll stock up on tarpaulin mittens for hot work and start:

from scraps of timber or logs, we will make two pyramidal plugs, the length of which should be 10 times the width of the base. The base area of each homemade plug should be almost 2 times larger than the square or rectangular hole that it has to plug;
let's try how the plugs will "sit", then on one of them we will select the longitudinal grooves on the four sides. They are needed to release the gas that accumulates when the filler is heated;
pre-anneal the workpiece in the area of the future fold;
let's prepare the filler. As it we will take clean building sand of medium grain size. In the absence of bulk building material, we will use the sand from the children's sandbox. First we sift it through a sieve with meshes of 2 or 2.5 mm to remove gravel and gobies from the packing. Large inclusions on the pipe surface can form unnecessary relief. Then we "pass" the sifted mass again, but this time through a fine sieve with 0.7mm meshes, so that dusty particles do not sinter when heated. All the screenings, as well as the filler at the end of the actions, will be returned to the sandbox;
calcine the filler at a temperature of 150 ° C;
we will hammer in one end with a wooden stopper, on which there are no channels for exhausting gases. Install a funnel at the other end. Depending on the size, we will install the workpiece at an angle or perpendicular to the ground. Pour the filler through the funnel in portions. Periodically tap on the walls of the product from bottom to top with a wooden or rubber mallet so that the sand is compacted. A dull sound will be a signal of sufficient compaction;
close the filled blank with a second plug;
mark the heating section on the workpiece with chalk;
fix the workpiece either in a vise with a template, or in a clamp. Install the material with the welded seam so that the welded joint is on the side. It is undesirable to stretch or squeeze along the seam;
heat the marked area red-hot, and carefully give the workpiece the required shape. We bend in one step with a forward, unsharp movement in a strictly horizontal or vertical plane;
after cooling down, compare the result with the template. If everything is in order, knock out or burn out the corks and pour out the sand.

The described method is good for the formation of single corner bends, because it is strongly not recommended to heat pipes several times. Metal loses strength from repeated thermal shock. However, when creating a rounded arch, repeated heating is inevitable. After all, it is unrealistic to do the work in one go, and chilled to a light cherry hue, i.e. up to 800 ° C, the workpiece can simply burst.

Option # 2 - cold method

Cold plastic deformation of profiled steel is carried out with or without filler. Material with a profile height of up to 10 mm does not require filling. A thicker pipe is best filled with sand or rosin. An alternative to the sand filler will be a tightly wound spring, the dimensions of which will allow it to be tightly installed in the cavity at the processing site. The spring washer will prevent a sharp change in the profile section at the bend points.

You can bend "cold" at home:

manually using the simplest devices such as bending plates, vice and mandrel;
with the use of a mobile profile bender - an improved analogue of a manual pipe bender. The profile bend differs from the device for bending round pipes only by the shape of the working roller recess;
by rolling on a homemade or factory roll forming machine, which can be made by hand or purchased ready-made.

It is wiser and more profitable to rent technical means of mechanization of bending if they are needed for a one-time construction of a greenhouse. If, in the future, the construction of green houses for relatives and neighbors or the construction of a beautiful metal fence, for example, there is a reason to acquire your own bending machine.

Bending devices and machines

In the family of devices and units for bending there are representatives of varying degrees of technical complexity. To begin with, consider the means for those who are puzzled by the question of how and by what means it is possible to bend a profile pipe without the use of special equipment. Then we move on to homemade rolling plants.

Variants of the simplest devices

The use of elementary "helpers" for cold deformation is regulated by the size of the material:

thin rolled pipes with a profile height of up to 10 mm are bent using a horizontal plate with holes. Metal pins are rigidly installed in the holes, which play the role of stops. Bend the product by placing it between the stops installed in the holes according to the bending radius. They start from the middle of the workpiece and gradually move towards the edges. The disadvantages of the method are the application of considerable muscular efforts and a rather low deformation accuracy;
pipes with a profile height of up to 25 mm are bent using roller devices operating on the principle of the Volnov machine. The metal workpiece is firmly fixed in a vice, and a physical force is applied to the workpiece through a roller. The bending is performed better and more uniformly than in the previous case. But from the performer, by analogy, remarkable efforts will be required.

To form a bend with a large radius of curvature, such as arcs for an arched frame, fixed rounded templates with clamps are used to fix the workpiece. These devices belong to the category of plane-parallel plates. The workpiece is forcefully "laid" in a groove, the dimensions of which are equal to the dimensions of the pipe. The pipe, which is manually bent with a mandrel, takes the shape of a predetermined contour.

Upgraded bending plate

If a home locksmith is not deprived of physical strength, for his own needs he will need a simple tool for a rather laborious deformation of a profile pipe. It can be made in the form of a panel attached with clamps to a work table or workbench. In the case shown in the photo, the bending plate is welded to a metal pedestal, but it is screwed with four bolts to the concrete floor of the workshop. To remove the device at the end of the work, it will be enough to unscrew the bolts. After dismantling, no fastening pins remain or rise above the floor surface, which means that nothing will interfere with movement and create traumatic threats.

The principle of manufacturing the working plane is extremely simple:

The bending plate is a panel cut from thick sheet iron.
The panel is welded to a profile pipe, installed according to telescopic rules in a pedestal post.
In the working plane, two holes were drilled for the bolts, which are stops.
The bending radius is adjusted by installing a suitable size nozzle on one of the bolts.
In order to maintain the alignment of the segments adjacent to the bend, a metal plate is installed above the workpiece, fixed with bolts.

The pedestal is multifunctional. Its owner has the opportunity to use it as a miniature workbench for performing an impressive number of plumbing operations.

Mandrel for bending the profile pipe

The method is suitable for products with a wall height of up to 25mm. The foreman will need a large workbench and a significant amount of free space around the working area. One edge of the workbench is punched with frequently spaced holes for fixing the mandrel and for choosing the optimal position of the part holding the pipe. The template for the forthcoming plastic deformation is cut from thick plywood. True, the plywood mandrel is only suitable for one-time bending procedures. If there is a lot of bending work to be done, it is better to weld the mandrels from a steel corner.

Using the manual profiler

Significant amounts of deformation work require mechanization. Mass production of curved parts will take too much health away from the performer. To facilitate bending, it is advisable to make a machine according to the drawing. They are mainly used for working with large-sized workpieces. The main working bodies of the hand-held unit are three rolls, two of which are fixed motionless. Changing the position of the third movable roll determines the bending angle.

If the above methods are not acceptable, then the future owner of the greenhouse has two options - renting a manual installation or ordering the manufacture of rounded parts. The process of deformation of the workpiece was demonstrated by a video: how it is easier to bend a profile pipe - by repeated rolling or physical impact, it is up to the performer to decide.

When working manually, it is important to follow the rules for bending shaped pipes and not make sudden movements. It is necessary to monitor the uniformity of deformation on the outside and inside of the rolled product. However, you should not be too upset about small folds on the inner surface of the fold: they can be corrected with hammer blows. Before starting work, it is necessary to make templates from wire, chipboard or gypsum board for verification and obtaining a result corresponding to the project.