EA036254B1 - Screw pile and method for producing the same - Google Patents

Abstract

The invention relates to the field of manufacture and use of steel piles with a screw element (auger) on their front cylindrical parts as well as on their taper parts, made of a welded steel pipe, which are elements of load-bearing structures that take up loads from upper structures and provide stability to them. The objective of the present invention is to strengthen the taper part of the pile where strength of welds is close to strength of welded steel. Thus, the technical result of this invention is the manufacture of a stronger and more chemically resistant taper part of the screw pile from the original seamed steel pipe. This objective is achieved by radial reduction of a welded steel pipe by hot forging until the desired geometry of the taper part is formed, wherein rotary forging is used to achieve uniformity in the composition and structure of the steel. Multiple rotary forging of metal of the lower part of the pile is performed to form a narrowing with a uniform structure and increased strength and chemical characteristics.

Description

The invention relates to the field of manufacture and use of steel piles with a screw element (auger) on the front cylindrical, as well as the tapering parts, made of a seam steel pipe, which are elements of load-bearing structures that receive loads from overlying structures and give them stability.

Screw piles are used in the construction of buildings and structures, in construction on difficult terrain, on soils with high humidity, peaty, clayey, sandy, with dissimilar soils, if necessary, add additional structures to an already built building without violating the overall integrity of the structure.

The use of a forged screw pile from a seam pipe is aimed at increasing the strength of the product, its bearing capacity and service life.

Terms and Definitions

A screw pile is a type of pile buried in the ground by the screwing method, including in combination with indentation. Screw piles consist of a cylindrical part, a tapered part with a spiral or a blade, a tip, a head and possibly a flange.

Cylindrical part - a part of a pile made of a pipe with a constant diameter that has not undergone mechanical processing of the workpiece shape.

Tapering part - a part of a pile made of a pipe that has undergone mechanical and heat treatment in order to obtain a given tapering and improve the strength characteristics of the initial material.

Pile narrowing - reducing the diameter of the pile body along its length. It can be conical, parabolic, exponential, or any other in accordance with the law of decreasing diameter in length. In general, it is given by the ratio of the change in diameter to the change in the longitudinal distance between the places where the diameter is measured. It is possible to express the constriction as a percentage, where the change in diameter along the length is divided by the distance between the diameter measurement points and multiplied by 100.

Seam pipe - the original steel pipe with a joint along the entire length in accordance with GOST 10704-91, GOST 28548-90, GOST 10705-80, GOST 10707-80, GOST 10706-76, GOST 11068-81, GOST 30456-97, can be used including a pipe with a diameter of 57, 76, 89, 108, 114 mm, a wall thickness of 3 to 4.5 mm, a possible material for the manufacture of a pipe - carbon and low-carbon steel 3 and steel 5 or their analogues. It is used as a blank for the manufacture of a pile body by hot rotary forging.

The tip is the part of the pile that enters the ground first when the pile is installed.

Spiral - a strip element of a pile formed by parts spirally welded onto the tapered and cylindrical part of the pile to improve the process of pile penetration into the ground.

A blade is a pile element cut from a plate, having a helical surface and designed to drag the pile into the ground along the axis when the pile rotates around its axis, having a width of at least 0.5 cm.

A polyhedral pyramid is the shape of a pile tip, formed by rotary forging until the internal cavity disappears and turned into a monolithic core with edges.

Lanceolate - the shape of a polyhedral pyramid of the pile tip, obtained by forging into a monolithic element. In cross section, it looks like a rhombus. This type of tip facilitates passage through plant roots, debris and stones in the ground.

Weld seam - a zone of a permanent connection made by welding. Differs in lower mechanical and chemical properties in comparison with the joined steel due to the possible presence of cavities, pores and other defects.

Rotary forging is a forging performed in a radial compression pattern. In a rotor with holes, strikers (two or more) move along the guides with one degree of freedom. The rotor with strikers can rotate. When rotating, the strikers strike the forging from diametrically opposite sides. Rotary forging is widely used for the production of high-quality rifled gun barrels [1].

Forge welding - forging welding, a type of pressure welding with heat treatment. By means of it, an integral connection is formed as a result of the action of the forging percussion tool on the metal in a plastic state [4].

Forging - (upsetting and upsetting), a forging operation, which consists in deformation of the workpiece by partial upsetting in order to create local thickenings by reducing the length (or other size) of the workpiece [4].

Control - observation for the purpose of verification; check [9]. Subdivided into current and day off. Current control - checking a product by a worker performing a technological operation for compliance with a given standard (parameter values in generally accepted units, a template) during a technological operation, if possible. Output or intermediate control is a separate operation to check the finished product or semi-finished product for compliance with the specified standard, taking into account the tolerances.

A product quality control system is a set of measures aimed at the timely determination of the quality parameters of production products with the required accuracy.

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System functions:

ensuring incoming control;

ensuring timely removal of defects in the production process;

ensuring compliance of the final product with the requirements of technical documentation;

preservation of information about manufactured products.

Condensate - water formed during condensation of water vapor on the walls of metal parts, in particular in cavities with access to atmospheric air.

Control window - a hole in a shielding element for direct observation and measurement of an inaccessible part (element) by means of a probe, borescope (endoscope) or other instrument.

The inner cavity is the space of the tubular element not filled with material.

Head - the upper area of the pile, protruding above the ground or located at ground level, may also have a flange, jibs, etc.

A flange is a piece of square, round or other shape with holes for bolts and studs, used to attach prefabricated pile elements to each other, to the structural elements of a building or structure located above, as well as to equipment for various functional purposes.

Curvature of the seam on the tapering part - the deviation of the seam from the plane formed by the axis of the pile and the unforged seam. Can be measured in degrees or percent. The pipe is laid horizontally with the seam upwards, a ruler is applied along the unforged seam so that part of the ruler passes over the tip. From the ruler to the narrowing, a perpendicular is lowered to the axis of the pile, which forms the projection point of the initial seam on the surface of the narrowing. Perpendicular to the pile axis along the surface of the circle, the distance from the projection point to the real seam is measured. This deviation is divided by the distance from the projection point to the beginning of the forging zone and multiplied by 100, which shows the amount of curvature of the seam in percent.

State of the art

There is a known solution (RU 170105, E02D 5/56, publ. 04/14/2017) for making piles from a pipe and a cast tip by joining pile elements by welding, by means of ring welding.

The disadvantage of this solution is the implementation of a circular welded connection of the elements, which reduces the reliability of the pile and forms the possibility of the tip detachment from the barrel.

A solution is also known (RU 81971, E02D 5/56, publ. 10.04.2009), where the screw pile contains a hollow barrel and a hollow tip, on the surface of which a helical blade is located. The pile elements are attached to each other end-to-end by means of a circular welded joint, which makes the probability of separation at significant loads other than axial, very likely.

To illustrate the method of manufacturing hollow one-piece forged products that differ in new properties from similar welded products, there is technical information from the article by A.B. Shirokorad Air bombs of the Red Army, chapter High-explosive air bombs ([2], paragraph 11-13) http://www.airages.ru/ru/abr.shtml.

In 1941, the Air Force adopted (for wartime) the FAB-100 KD high-explosive bomb, developed by S.G. Dobrysh (NII-6). This bomb was filled with a liquid explosive mixture of KD, consisting of nitric acid, dichloroethane and oleum (ratio 60:40:30). In terms of explosive characteristics, this mixture is equivalent to TNT. The high-explosive effect of the FAB-100 KD was the same as that of the FAB-100 loaded with TNT.

The FAB-100 KD equipment technology was extremely simple (alternate pouring of components into the body of an aerial bomb), so it took no more than one to two months to organize production.

From the beginning of 1942, the Air Force began to use the FAB-100 KD. At that time, this was very important, since the equipment factories were evacuated, and there was not enough TNT and other explosives to equip bombs. Production of the FAB-100 KD was discontinued in 1944 due to the fact that the mobilization stock of solid-forged hulls was completely used up. Attempts to use welded hulls were unsuccessful: filled with a KD mixture, they flowed along the welded seams.

The use of the rotary forging method on a thin-walled welded structure improves the strength characteristics of the product by removing defects (voids, thermal stresses, slag, etc.) from the weld zone, which, in turn, dramatically increases the overall chemical resistance of the final product.

The closest solution for both the method and the device is the Screw pile, patent RU 182309 U1 (patent application 2018102790 dated 01.24.2018), selected as a prototype.

The disadvantage of this technical solution is the use of a solid steel pipe as a workpiece (that is, consisting of one thing; not composite [7], consisting, made of one substance, from one piece, not a composite [8]) steel pipe, which has a much larger spread in the tolerances for cylindricality and wall thickness (GOST 8732-78, p. 5, p. 7-8, tables 2 and 3), which, when the screw is connected to the pipe body, reduces the manufacturability due to the mismatch in the dimensions of the workpieces, and deviations in the wall thickness pipes make possible the occurrence of stress concentration zones, including due to the unevenness of the spiral weld. Also, operations (heat treatment followed by forging and hardening, utility model formula RU 182309) provokes the creation of a more fragile pile tip than the use of hot rotary forging followed by

- 2 036254 thermal tempering, which is an important property of the pile when used in soils containing incompressible elements (boulders, debris, rocky outcrops, frozen zones, roots, etc.). The fundamental difference between the proposed solution and the prototype is the use of a seam welded pipe as a workpiece, as well as hot rotary forging and leveling heat treatment in order to reduce inhomogeneities in the form of stress concentrators in the steel of the pile body and increase the strength of the final product, where new in the prior art is the use of weld geometry to assess the quality of the resulting screw pile.

Technical problem and technical result

The technical problem to be solved by the present invention is the strengthening of the tapered part of the pile, where the strength of the welds will be close to the strength of the steel being welded. Thus, the technical result of this invention is the production of a stronger and more chemically resistant tapered part of the screw pile from the original seamed steel pipe.

The use of the original seam steel pipe (see the glossary, for example, GOST 10704-91) makes it possible to increase the accuracy of the workpiece from 0.5-1.25 mm for a solid pipe (GOST 8732-78) to 0.2-0.8 mm for longitudinal seam ( GOST 10704-91, table 3, clauses 9-10), which significantly reduces the number of rejects in the production of screw piles (mismatch between the internal dimensions of the spiral and the external dimensions of the pile), reduces the likelihood of stress in the pile body due to the more cylindrical and even wall of the initial welded pipe.

Brief description of the invention

The solution to the technical problem posed is radial compression of a steel seam pipe by hot forging until the desired geometry of the tapered part is formed, where rotary forging is used to achieve uniformity in the composition and structural structure of the steel. Multiple rotary hammering of the metal of the lower part of the pile is performed to form a narrowing with a uniform structural structure and increased strength and chemical characteristics.

It is known that rotary forging of hollow cylindrical blanks without mandrels leads to an increase in the wall thickness of the blank ([1], Fig. 12).

Forging on radial swaging machines has a number of advantages: high accuracy of the products obtained, the ability to achieve high total reductions without destroying the integrity of the original material, higher productivity compared to traditional forging methods on presses and hammers, etc. [5]

Thus, rotary forging has potential as a method of severe plastic deformation. It is known that obtaining an ultrafine-grained state by methods of severe plastic deformation can significantly improve the performance properties of various metals and alloys. [6].

The proposed method for making a pile consists of using a seam welded pipe as a workpiece, hot rotary forging and for forming a taper and a forge-welded tip, tempering the pile, welding a spiral and a flange, drilling the required holes, where new in the prior art is the use of weld geometry to evaluate quality of the resulting screw pile.

The indicated technical result of strengthening and chemical resistance of the pile is achieved by manufacturing a screw pile having a cylindrical part, a tapered part with a spiral, which can be made in the form of a blade, a tip, a head made of a seam steel pipe by hot rotary forging in such a way that the bending of the welded of the seam in relation to the longitudinal axial section of the pile is an angle of at least 4 °, while the deviation of the linear dimensions of the seam is carried out by at least 20% of the initial value. The narrowing of the pile in this case can be from 2 to 30%. The tip of such a pile is formed in one piece, it can have a lanceolate shape or the shape of a polyhedral pyramid. Additionally, holes can be made in the pile to remove condensate and estimate the thickness of the forged material and the geometry of the inner part of the seam, which are located on the border of the zone of disappearance of the gap in the inner cavity. Such holes can be made perpendicular to the pile axis or at an acute angle to the longitudinal pile axis.

Also, the specified technical result is achieved by using a method for manufacturing a screw pile from a seam steel pipe by hot rotary forging, including radial compression of a steel seam pipe by hot forging until the geometry of the tapering part is formed until the seam is curved on the tapering part of at least 4%, then the tip is forged. In this case, the forging of the pile tip is carried out until the gap in the inner cavity of the head part disappears and a one-piece pile tip is formed, forging is carried out simultaneously with the punching of the pile tip, giving it a lanceolate shape. Additionally, an oval-oblong hole is made at the head of the pile with a flange to control the initial pipe wall thickness and the initial weld shape. The piles can be released after the formation of the narrowing, which provides additional strength. For additional chemical resistance and anti-corrosion effect, the pile can be hot or cold galvanized.

The bend angle of a weld bead is defined as the angle between the axis and the tangent to the bead curve. It should be borne in mind that the surface on which the angle is measured is not flat. To compensate for the curvature of the surface, the projection of the point of intersection of the weld from the axis onto the extension of the cylindrical surface of the pipe (sweep) is introduced. On a cylindrical projection unfolded into a plane, the angle between the continuation of the projection of the straight seam line to the tangent to the projection of the curved seam line will be the angle of deflection of the seam.

Measurement of the angle in this case looks like this: the pile is placed horizontally on two supports with the seam up. From above, the probe is vertically lowered to the point of the beginning of the bend of the seam (the beginning of the forged zone) and fixed. The pile is shifted axially towards the head by a distance S, rotated so that the seam is under the probe, the angle L of the pile rotation around its axis (in degrees) is measured. The angle of rotation is converted into a distance on the projection using the formula S = pixDxL / 360, where S is the distance, mm; D is the diameter of the unforged pipe, mm; L - angle, degrees; pi is pi. Next, a scan of the projection of the seam of the tapering part is drawn in points every 10 mm (or another distance sufficient for measurement accuracy), a seam projection curve is obtained. Then the tangents to the seam projection curve are constructed and the angle between the obtained tangent and the projection of the axis is measured with a goniometer or protractor (Fig. 8).

From the above presentation, it is clear that the invention is not limited to the above implementation. Numerous possible modifications, changes, variations and substitutions, while retaining the spirit and form of the present invention, will be apparent to those skilled in the art.

The proposed technical solution is illustrated by the following drawings.

FIG. 1 - screw pile, general view.

FIG. 2 - isometric projection of the pile with a traced seam zone on the cylindrical part and as it approaches the pile tip.

FIG. 3 - section of the seam in the area of narrowing.

FIG. 4 is an orthogonal section of a lanceolate tip in the form of a quadrangular pyramid.

FIG. 5 is an orthogonal section of a hexagonal pyramid-shaped tip.

FIG. 6 - General view of the holes in the tip, section, the presence of the pile axis.

FIG. 7 - frontal projection of the pile.

FIG. 8 - seam deflection angle.

FIG. 9 is a photograph of a pile.

FIG. 2, 4, 5 and 7 the following positions are available:

- cylindrical shaft of the screw pile;

- lower part, narrowing of the pile;

- pile tip;

- lanceolate tip in the form of a polyhedral pyramid;

- lanceolate tip;

- hole in the tip area;

- spiral made of steel tape;

- flange;

- holes for fasteners;

- control window;

- jibs;

- forged seam;

- unbroken seam;

- cylindrical projection;

- sweep;

- seam projection;

- angle measurement point and tangent to the seam projection;

- measured angle.

Detailed description of the invention

When a given geometry of a product from a pipe is achieved by the rotary forging method, the effect of steel creep is observed, expressed, for example, in a change in the relative dimensions of the weld from the original shape - from the ring sector in the section to a wedge-shaped one (the ratio of the weld width to its thickness changes as the pipe diameter decreases), fig. 1. At the same time, there are changes in the size of the seam zone, spreading boundaries of the seam material - pipe material, changing characteristics of the seam material in the direction of increasing mechanical parameters and an increase in corrosion resistance. There are also deviations of the longitudinal seam of the pipe from the line lying in the same plane with the axis of the pile, as well as the curvature of the initially straight weld in the form of a spiral line (left or right), Fig. 2, 3, 9.

The applicant's pilot production showed that, in particular, a pile made of a seam pipe demonstrates a change in the seam width from 6 to 4 mm, the seam thickness from 4 to 8.4 mm in the area of the hole by 390 mm of narrowing and a deviation of the initial seam line from the parallel the pile axis by 23 mm by 360 mm of the tapering part of the pile (Fig. 9).

An example of calculating the change in the linear dimensions of a seam:

the width of the seam on the unforged part was 6 mm, on the forged part it became 4 mm; 6mm / 4mm = 1.5 times;

- 4 036254 (1.5-1) x 100 = 50% difference, the set value of 20% is exceeded, which means that this parameter of validity is met;

the seam thickness on the unforged part was 4 mm, on the forged part it became 8.4 mm; 8.4mm / 4mm = 2.1 times; (2.1-1) x100 = 110%; the set value of 20% has been exceeded, which means that this validity parameter has been met.

Since the compaction and thickening of the seam and its curvature are the result of rotary forging, it is possible to take the curvature of the seam as an additional criterion.

Example: the distance from the non-forged part to the projection point is 360 mm, the deviation of the original seam line from the parallel to the pile axis is 23 mm, (23 mm / 360 mm) x 100 = 6.38%. The set value of 4% has been exceeded, which means that this shelf life parameter has been met.

An example of product quality control during repeated rotary forging of a seam cylindrical billet during the formation of a tapering part of a pile is rejection of billets according to the following parameters:

the geometry of the pile is broken, there is jamming or, on the contrary, protruding parts;

insufficient wall thickening in the area of the hole (less than 20% of the original pipe wall thickness);

insufficient change in the width and thickness of the seam in the area of the tip (less than 20% of the original value);

insufficient degree of curvature of the seam in the tapering part (at least 3 ° from the longitudinal axis).

The control is carried out through a hole in the flange and holes at the pile tip. The joint width is controlled directly on the surface.

Thus, new in the proposed technical solution is the dosed application of thermal and mechanical effects on the seam pipe in the form of heating and multiple shock-shear loads during rotary forging. The dosage criterion is an increase in the thickness and a decrease in the width of the seam, the curvature of the weld from a straight seam. The visible change in the geometry in the size of the weld in the tapering part of the pile should be at least 20% of the original linear dimensions, which characterizes the required degree of compaction of the steel of the seam and the walls of the tapering part of the pile in order to improve the mechanical properties of the pile and improve the corrosion properties of the pile (Fig. 1) ...

During rotary forging, changes in the geometric parameters of the original workpiece are observed, such as a decrease in the diameter of the pipe along the length, an increase in the thickness of the metal as it approaches the tip. In this case, geometric changes in the seam are also observed. First of all, the seam profile changes (Fig. 3). As you move along the seam towards the tip, the shape of the seam changes from a ring segment (a sector on a circle between the inner and outer surface of the pipe) into a triangle (with its apex facing the pile axis), where the degree of forging will be illustrated by the angle at the apex of this triangle. The greater the degree of mechanical action, the more obtuse the angle, up to its disappearance with sufficient stirring of the metal with the complete disappearance of the boundaries of the seam zone (Fig. 5). The straightness of the seam of the original seam pipe also changes, which is expressed in the deviation of the seam from the plane of the longitudinal axial section of the pile and the formation of a curved line on the narrowing surface.

Pilot production of BAU showed that the optimal ratio of the narrowing (reduction of the diameter of the pile body along the length) at the base and the top of the narrowing section of the pile is in the range from 2 to 30%, and for different applications the narrowing can be conical, parabolic, exponential. In general, the constriction is given by the ratio of the change in diameter to the change in the longitudinal distance between the places where the diameter is measured. It is possible to express the constriction as a percentage, where the change in diameter along the length is divided by the distance between the diameter measurement points and multiplied by 100.

This range is optimized for the use of high torque installation mechanisms. Thus, a ratio of 30% is most optimal for machine installation, and a ratio of 2% is more suitable for manual installation.

The installation of screw piles is carried out by the method of twisting and possible additional indentation, into the ground, for which the pile is set in the initial position determined by the project, screwed in (manually or mechanically), thereby achieving the necessary immersion. Here the screw part of the pile works as a screw and, when rotating, plunges the body of the pile, where the tapering part pushes and compacts the soil.

When making a narrowing in the process of upsetting (forging), a gradual narrowing of the diameter of the pipe section being formed is achieved and at the end of the operation a monolithic tip is formed - a pile element completely filled with metal of a uniform composition, without the initial seams of the original pipe. The temperature at which this technological operation is carried out is sufficient for forging welding - complete, without traces of the seam, filling the inner volume of the pile tip and joining all layers of metal into a monolithic body (Fig. 2).

On rotary radial crimping machines, it is possible to produce products not only of round, but also of faceted section. Obtaining faceted products on rotary swaging machines with a rotating tool can be achieved by rotating the workpiece at a speed equal to the spindle rotation speed. [3]. Thus, when carrying out the thermal forging process, it becomes possible to form a lance-shaped pile tip having a diamond-shaped cross-section (Fig. 4) to ensure easier penetration of the pile into the soil, where the lance-shaped edges of the pile tip simultaneously cut through the parent soil and shift inclusions uncompacted soil elements (pebbles, roots, etc.) away from the pile. In the same way, with rotary forging, the outer surface of the tip in the form of a polyhedral pyramid can be formed (Fig. 6). The presence of a polyhedral pyramid shape on the tip strengthens the tip itself against horizontal bending loads and allows the unconsolidated soil elements to move away from the pile, which significantly reduces the likelihood of the auger belt breaking at the head of the pile. Unlike the lanceolate edges of the pile tip, the sides of the pyramid are less susceptible to bending and wear during soil compaction.

The formation of the tip as an important element of the screw pile, made from a seam pipe, imposes a great responsibility on the rotary forging technology, since this area of the pile experiences the maximum compressive, bending and twisting load. Quality control of the material obtained as a result of forging welding at the pile head is carried out visually and instrumentally - upon changes in the geometric parameters of the initial seam (width, thickness, change in the angle of the seam facing the pile axis, deviation of the seam from a plane common with the pile axis), observation the disappearance of the suture zone.

In the pile body formed by the rotary forging method, at the border of the minimum narrowing of the hollow pile body and the monolithic tip, through drilling is performed with the formation of one or more holes (through the longitudinal axis of the pile or along the chord), Fig. 6. These holes are used to control the filling of the tip with metal, measure the thickness of the metal at the head of the narrowing of the pile and determine the geometric parameters of the modified seam. Also, these holes are used to remove condensate from the inner cavity of the pile into the ground.

It is important to be able to control the initial wall thickness of the original pipe that has not undergone forging. Since the end of the pile is closed with a flange, a round or oval-shaped through hole (control window) is made in it, which falls on the end of the seam and allows one to estimate the initial metal thickness of the pipe wall and the shape of the seam in the section. (Fig. 7).

In case of plastic deformation of steel, tempering of the product is used to relieve possible internal stresses and to increase the toughness of the material. As a result of tempering, the steel retains high hardness, but at the same time quenching brittleness is eliminated. The transformation of quenched martensite into tempering martensite helps to stabilize the dimensions of the part, increases strength and elasticity at medium hardness.

To increase the chemical resistance of the pile, increase its anti-corrosion properties, the pile can be hot or cold galvanized by dipping it into a zinc-containing solution.

The essence of the utility model is illustrated by drawings (Figs. 2 and 7), which show a screw pile.

The screw pile contains a barrel 1 made of a seam pipe, the lower part 2 of which is narrowed by means of hot rotary forging, a tip 3 is formed, which is a forged welded monolith of plastic-deformed steel, having the shape of a polyhedral pyramid 4 and a spear-shaped end of the pile 5. At the border of the narrowing and the tip holes 6 are made to control the degree of transformation of steel according to the geometric parameters of the weld.

A spiral 7 made of steel tape is welded onto the tapering body of the pile formed by hot rotary forging to form a screw and the possibility of introducing the pile into the ground by rotation. The weld is made continuously along the formed helix. The auger itself is located on the cylindrical part, the tapering part and comes onto the tip. Flange 8 is attached and welded to the unchanged end of the pile, which is the original seam pipe, to redistribute the bearing load from external structures through the pile body onto the ground.

To control the technological operations to change the properties of the steel pipe in the flange, in addition to the technological holes of the fastener 9, there is a control window of round, oval, oval-oblong or other shape 10, located above the end of the wall of the original seam pipe in the seam area, which allows you to see the profile of the original seam from the end face for assessing the degree of transformation of the steel material

The product created according to the claimed method works as follows. When installing a pile into the ground by means of prevailing rotation before pressing, the pile body is deepened due to the thrust provided by the auger, where the narrowing part of the pile expands and compacts the soil, and the tip, represented by the spear-shaped end of the pile, destroys the uncompacted material and presses it into the compacted parent rock, into to the side of the pile axis, by means of the superior polyhedral tip pyramid.

Installation and load on the pile are provided through the fastening holes welded to the body of the pile flange and jibs 11.

In the present application materials, a preferred disclosure of the implementation of the claimed technical solution is presented, which should not be used as limiting other, particular embodiments of its implementation that do not go beyond the scope of the claimed scope of legal protection and are obvious to specialists in the relevant field of technology.

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Literature.

1. Golyshev I.V., Ph.D. Abstract of the thesis Rotational forging of hollow cylindrical blanks according to VAK 05.03.05, Tula, 2008.http: //www.dissercat.com/content/rotatsionnaya-kovka-polykh- tsilindricheskikh-zagotovok # ixzz5TbwVTjbl

2. A.B. Shirokorad. Red Army air bombs, chapter High explosive bombs (paragraph 11-13). http://www.airpages.ru/ru/abr.shtml

3. Radyuchenko Yu.S. Rotary forging. M.: Mashlit, 1962.

4. V.G. Shmakov. Forge in modern economy, Moscow: Mechanical Engineering, 1990.

5.V.A. Tyurin, V.A. Lazorkin, I.A. Pospelov and others, under total. ed. V.A. Tyurin. Forging on radial swaging machines. Moscow: Mechanical Engineering, 1990, 256 p.

6. Valiev R.Z., Alexandrov I.V. Bulk nanostructured metallic materials: preparation, structure and properties. M .: Akademkniga, 2007, 398 p.

7. Explanatory dictionary of Efremova.

8. Small academic dictionary. Moscow: Institute of the Russian Language of the USSR Academy of Sciences. Evgenieva A.P., 1957-1984).

9. Dictionary of the Russian language: In 4 volumes / RAS, Institute of linguistic. research; Ed. A.P. Evgenieva. - 4th ed., Sr., M .: Rus. lang .; Polygraphs, 1999.

Claims (17)

CLAIM 1. A screw pile with a cylindrical part, a tapering part, a spiral, a tip, a head, made of a seam steel pipe by hot rotary forging in such a way that the curvature of the weld in relation to the longitudinal axial section of the pile is at least 4 °. 2. A screw pile according to claim 1, characterized in that the constriction is between 2% and 30%. 3. A screw pile according to claim 1, wherein the tip is formed in one piece. 4. Screw pile according to claim 1, characterized in that the tip has a lanceolate shape. 5. A screw pile according to claim 1, characterized in that the tip of the pile has the shape of a polyhedral pyramid. 6. Screw pile according to claim 1, characterized in that the spiral is made in the form of a blade. 7. A screw pile according to claim 1, characterized in that it contains at least one hole for removing condensate and assessing the thickness of the forged material and the geometry of the inner part of the seam, which is located on the border of the zone of disappearance of the gap in the inner cavity of the pile. 8. A screw pile according to claim 7, characterized in that the hole is located at an acute angle to the longitudinal axis of the pile. 9. A screw pile according to claim 7, characterized in that the hole is located perpendicular to the longitudinal axis of the pile. 10. A screw pile according to claim 1, characterized in that the end of the pile is closed with a flange containing the hole. 11. A method of manufacturing a screw pile from a seam steel pipe by hot rotary forging, including radial compression of a steel seam pipe by hot forging until the geometry of the tapering part is formed until the seam is curved on the tapering part of at least 4%, then the tip is forged. 12. A method of manufacturing a screw pile according to claim 11, characterized in that the pile tip is forged until the gap in the inner cavity of the head part disappears and a solid pile tip is formed. 13. A method of manufacturing a screw pile according to claim 11, characterized in that the forging is carried out simultaneously with the punching of the lanceolate shape of the pile tip. 14. A method for manufacturing a screw pile according to claim 11, characterized in that an oval-oblong hole is made on the head flange to control the initial pipe wall thickness and the initial seam shape. 15. A method for manufacturing a screw pile according to claim 11, characterized in that after the formation of the narrowing, the body of the pile is tempered. 16. A method for manufacturing a screw pile according to claim 11, characterized in that the pile is cold-galvanized. 17. A method for manufacturing a screw pile according to claim 11, characterized in that the pile is hot-dip galvanized.