UA73836U - Method of pressure welding - Google Patents

Abstract

A method of pressure welding articles from similar and dissimilar metal materials includes connection to at least one of welded blanks of a transition element, through which welding is carried out, the welding process is carried out up to achievement of a given upsetting allowance. Prior to welding in the center of cross section of at least one of the blanks coaxially to its axis a recess is made. In the recess a transition element is rigidly secured flush with the surface of welded blank. Then welding the blanks is carried out.

Description

The useful model belongs to the field of welding technology and can be used in the production of parts from homogeneous or dissimilar metal materials by pressure welding methods, in particular friction welding (ST) or contact butt welding (CS).

Pressure welding methods can successfully connect various materials that differ significantly in their mechanical and thermophysical properties. However, there are a significant number of combinations of materials, direct welding of which does not ensure obtaining high-quality joints. In particular, these include combinations of steel with titanium and high-strength aluminum alloys, bronze, niobium, vanadium, etc. In some cases, it is possible to obtain a high-quality connection, but its properties quickly degrade under the conditions of operation of the welded unit, for example, when operating welded units made of austenitic and pearlite steels at high temperatures.

There are well-known methods of pressure welding, which are aimed at solving the problem.

Methods of pressure welding of dissimilar combinations of metal materials are based on the use of a transition element made of other metals and alloys, which form high-quality welded joints with the materials being welded and do not lose their properties during the operation of the welded assembly. Connections made using a transitional element can be more durable and more reliable in operation.

A known method of friction welding of a homogeneous and heterogeneous combination of materials due to an intermediate element, which is placed in the recess of one of the workpieces before welding | article Zazzapi R., Meiyiat U.K. Egisbyop ueidipd oi ipsotratsyrie tagegiaI5. - M/Eidipa

UChoshgpa!.-1988. - Mo 11. - R. 264-5-270-5th. The recess has a diameter close to the diameter of the workpieces and serves to prevent the ejection of the intermediate element from the contact zone during the relative rotational movement of the workpieces during friction welding. The article provides specific data: when welding workpieces with a diameter of 12.7 mm, a transition element with a diameter of 10 mm and a thickness of 1 mm is freely located in a cylindrical recess.

As follows from the data presented in the article, the strength of the welded joint at the level of the indicators of the main material of the workpieces is achieved only for a homogeneous combination of workpiece materials when using an intermediate element of the same material.

For a heterogeneous combination of materials, the strength of welded joints is significantly lower than the corresponding indicators for the main material of the workpieces. It is known that during pressure welding, in order to form a high-quality joint, it is necessary to ensure a certain amount of deformation of one or both workpieces, which is accompanied by the displacement of oxides and adsorbed films beyond the cross-section of the workpieces. As practical experience shows, the low strength of the combined joints of this technical solution is associated with the impossibility of ensuring high-quality joint formation simultaneously in two contact planes in the friction welding process: in the contact plane of the first and second blanks with the intermediate element. Since the intermediate element is freely located in the recess, the relative rotational movement, which means the release of heat, occurs in the contact plane (friction plane) of the transition element with one of the workpieces, at this time the contact zone with the other (second) workpiece can be oxidized. As a result of heating and plasticizing of the material of the intermediate element, the friction plane can move to the zone of contact with the second of the workpieces, as a result of which the relative rotational movement of the intermediate element with the first workpiece stops. Thus, the strength indicators of welded joints are determined by the possibility of simultaneous displacement of oxidized layers of metal on two friction surfaces beyond the cross-section of the blanks. Obviously, this feature of the described technical solution did not allow it to find industrial application.

There are a number of technical solutions that involve sequential welding of one of the blanks with a transitional element, mechanical processing of the transitional element to specified dimensions, and subsequent welding of the blanks through the transitional element.

The known technology of obtaining a welded adapter of titanium VT 1-0 with stainless steel 12Х18Н10Т (article Lytvyn L.V., Kharchenko G.K., Chernenko I.A., Reshetnyak A.V. Friction welding of titanium-steel adapters using an aluminum interlayer / / Automatic quarrel. - 1986. - Mo. 5. - Sat. 73-74). The adapter is made by friction welding by connecting through a transition element - aluminum. First, an aluminum workpiece is attached to the titanium workpiece by friction welding, its mechanical processing is carried out, after which the steel workpiece and the titanium workpiece are welded through an aluminum transition element. In this case, the workpieces made of titanium and steel are not deformed, and the formation of the welded joint occurs due to the plastic deformation of only the aluminum transition element. The material of the transition element remains in the welded joint in the form of a continuous layer because the cross-sectional area of the workpieces is the same thickness, which determines the low mechanical properties of the titanium-steel adapter. Another disadvantage is that a significant amount of material of the intermediate element is lost in the process of the first and second welding and during the mechanical processing of the transition element to the specified dimensions.

There are technical solutions that involve the use as a transition element of a material close in mechanical properties to the properties of the workpieces to be welded.

So in the USSR patent Mo 1122209 IPC V2ZK 11/04, publ. 1984.10.30, Bull. Mo 40| an intermediate element (intermediate part) made of austenitic steel is used to connect austenitic manganese steel castings of crosspieces with carbon steel rails, and first the transition element is connected to the carbon steel rail by contact butt welding, then mechanical processing is carried out until the specified length of the transition element is reached ( 15-25 mm), after which the rail is welded with a cross through an intermediate element, which is partially pushed out of the welding zone. During the welding process, both the workpieces to be welded and the transition element are deformed, which determines the high mechanical properties of the combined welded joint. The disadvantages of this technology are low productivity and a significant loss of the material of the transition element - austenitic steel, because during the first welding of the rail with the transition element, the latter must have significant dimensions (length 50 mm), and before the second welding, mechanical processing to the specified thickness is required.

A well-known technical solution that provides increased productivity in the production of a combined welded joint | article Chernenko I.A., Zakharov A.G., Tsurul I.A., Forostovets

B.A. Friction welding of bronze Bro12 and Silumin with steels through an intermediate layer of copper and aluminum // Automatic welding.-1991. - Mo 11. - E. 56-57|. The essence of the given method is to perform friction welding of two non-rotating workpieces with the help of a transitional element clamped between them, which rotates during the welding process. This technology is implemented on specialized equipment - a machine for friction welding with a rotating insert. As an example of implementation, the technology of friction welding of workpieces with a diameter of 25 mm from Bro12 bronze and 40X steel through a transition element - a copper insert with a square section of 45x45 mm is given, and a much larger section of the insert is necessary for

From the transmission of torque during its rotation during the welding process. The main disadvantage of this technology is the impossibility of obtaining welded joints with an insignificant final thickness of the intermediate element, since when its thickness is reduced during the welding process to a certain value (approximately 15...20 mm) due to heating and plasticization of the insert material, it is impossible to ensure the transmission of torque into the welding zone, which is a necessary condition for the implementation of the friction welding process and the formation of a high-quality joint. Therefore, this technology has not found practical application in industry.

The closest analogue of the proposed useful model is the method of pressure welding of products made of homogeneous and dissimilar metal materials, in which at least one of the workpieces to be welded is connected to a transitional element through which welding is performed, the welding process is carried out until the specified allowance for the deposit is reached, article M Mataaki, T. UMagapabre, U. M|pdo, M. Tarispi. - Steer hirishte rgorepiez apa igasiyge yure og 9St1-1Mo-mM-Mr/18Stg-8MI vievii! adivvitiyag ioipiv // M/eidipdu ip She ugopa.-2011. - Mo 1; 2. - Mine. 55. - R. 67-75.

The described technical solution consists in the fact that when obtaining a heterogeneous connection of the first workpiece made of martensitic steel 9St-1Mo-M-MBB with the second workpiece made of austenitic steel 18St-8MI, in order to prevent the formation of an intermediate brittle layer, a transition element made of austenitic steel 3095 or 3105. The transition element was first connected by welding to the first workpiece, machined to the specified size of the transition element, after which the first workpiece was connected to the second through the transition element. To perform the first and second connection, the method of pressure welding - friction welding was used. An essential feature of the described technical solution is that the material of the transition element is close in mechanical properties to the material of the workpieces to be welded, and in the process of the first and second welding, the process of forming the joints is carried out due to plastic deformation by a given amount of both the transition element and the workpieces , which are welded. This ensures high mechanical and operational properties of the combined connection.

However, the disadvantages of the technical solution based on the closest analogue are low productivity and a significant loss of the valuable material of the transition element - austenitic steel, because when welding the first workpiece with the transition element, the latter must have significant dimensions for reliable fixation in the clamp of the welding machine, and before welding with the second workpiece, mechanical processing of the transition element to the given dimensions.

In addition, for all the above technical solutions - analogues and the closest analogue - the common drawback is the impossibility of obtaining combined welded joints with an intermediate element, the thickness of which varies significantly along the cross-section of the workpieces to be welded. Since, under the conditions of operation of the welded product, the distribution of mechanical stresses over the cross-section of the workpieces is usually uneven (for example, in the central part of the cross-section of the workpieces, the mechanical stresses during compression or tension are significantly different compared to the peripheral part of the cross-section), then obtaining a welded product with the thickness of an intermediate element, the thickness of which, if necessary, changes along the cross-section of the blanks, is quite relevant.

The basis of the proposed useful model is the task of increasing the efficiency and simplifying the method of pressure welding of products from homogeneous and dissimilar metal materials by choosing the optimal structural form, structure and dimensions of the transition element, as a result of which the formation of a zone of combined connection is ensured through an intermediate element that can to have both the same and different thickness across the cross-section of the blanks, and the production productivity of the combined welded joint is also significantly increased.

The problem is solved by the fact that in the method of pressure welding of products made of homogeneous and dissimilar metal materials, in which at least one of the workpieces to be welded is connected to a transitional element through which welding is performed, the welding process is carried out until the specified allowance for the Isos deposit is reached, respectively to the proposed useful model, prior to welding in the center of the cross-section, at least one of the workpieces is made coaxially to its axis, the area of which is (0.05-0.5) of the cross-sectional area of the workpiece, and the depth is (0.1-1 ,0) from the value of Ios, the transition element of the surface levels of the workpiece to be welded is rigidly fixed in the recess, after which welding of the workpieces is performed.

At the same time, the recess and the transition element are given the volume and corresponding shapes, and the shape is chosen from the series: cone, hemisphere, cylinder, prism.

In addition, as a transition element, a material with a structure chosen from a series of: microcrystalline, submicrocrystalline, nanocrystalline structure is used.

The technical result indicated above, which is achieved in the process of implementing the proposed useful model, is due to features that distinguish it from the features of similar technologies described in accordance with the known state of the art, in particular, specified in the invention, which is considered the closest analogue.

Unlike the known technology of pressure welding, where the transition element is attached to at least one workpiece by applying it by welding over the entire cross-sectional area of the workpiece, in the proposed useful model, the transition element is rigidly fixed, in particular, by the method of welding, surfacing or mechanical fixation in the depression of the workpiece, which has the area (0.05-0.5) of the cross-sectional area of the workpiece, which allows you to significantly save valuable metals or alloys and provides a significant increase in production productivity. Making a recess in the form of a cone, cylinder, hemisphere, prism with a depth (0.1-1.0) of the welding allowance Ioss ensures the appropriate shape of the transition element, which, as a result of pressure welding with a specified allowance for the deposit, ensures the formation of a high-quality combined welded connection along the entire cross-section of the workpieces through a transition element, the thickness of which in the combined welded joint can be constant (the same) or different across the cross-section of the workpieces depending on technical feasibility.

Achieving such characteristics is possible primarily due to the fact that the proposed method of pressure welding implements a phenomenon established as a result of comprehensive research, inherent in pressure welding methods, in particular friction welding and resistance butt welding. It is known that during the heating and axial deformation of the workpieces in the process of pressure welding, the contact volumes of the metal of the workpieces move under the action of shear stresses in the direction from the central to the peripheral part of the cross section of the workpieces.

The phenomenon established by the authors, which is the basis of the proposed useful model, consists in the fact that the material plasticized during heating of the central part of the cross-section of the workpieces during its movement in the direction of the peripheral part of the workpieces displaces the contact volumes of the metal of the peripheral areas not only in the radial direction beyond the cross-section of the workpieces, but also in the axial direction deep into the workpieces. The process of deformation of the plasticized metal in the contact zone occurs in the direction from the depth of the blanks in the central part of the cross-section with its exit to the contact zone in the center of the cross-section of the blanks and further in the radial direction, while the peripheral volumes of the metal are displaced in the axial direction into the depth of the blanks and in the radial direction beyond the cross-section of the blanks.

When a certain amount of axial deformation of the workpieces is reached, the contact zone of the workpieces is formed only from the material that before welding was on the surface and at some depth in the central part of the cross-section of the workpieces, which before welding had an area (0.05-0.5) of the total cross-sectional area blanks, and the plasticized metal of the peripheral part of the cross-section is completely displaced in two directions - in the axial depth of the blanks and radially - beyond the cross-section of the blanks. Thus, it was established that with pressure welding methods, in particular, friction welding and resistance butt welding, the "source of supply" of the material that forms the joint plane and completely fills the contact volumes along the entire cross section of the workpieces is the volume of the material of the workpieces, which before welding, it occupied an area (0.05-0.5) of the total cross-sectional area of the workpieces, and a depth that depends on the size of the allowance for the deposit during welding.

Based on the study of the described regularity of the formation of the joint zone in pressure welding methods, it was established that during pressure welding of workpieces through a transitional element, which before welding is fixed in the recess of one or both workpieces, the area of which is (0.05-0.5) of the total of the cross-sectional area of the blanks, the guaranteed filling of the contact zone of the blanks with the material of the transition element over the entire cross-sectional area of the blanks is achieved with a depth of embedment within (0.1-1.0) of the amount of allowance for settlement Ios.

In the case when the recess area is less than 0.05 of the total cross-sectional area of the workpieces, filling of the contact zone of the workpieces with the material of the transition element is not ensured throughout the cross-sectional area of the workpieces, in particular in the peripheral part of the cross-section.

In the case when the recess area is greater than 0.5 of the total cross-sectional area of the workpieces, the contact zone of the workpieces is guaranteed to be filled with the material of the transitional element over the entire cross-sectional area of the workpieces, but the volume of the material used for the manufacture of the transitional element increases unreasonably, productivity decreases, the effectiveness of the proposed useful model decreases.

In the case when the depth of the recess is less than 0.1 of the allowance

Koo) on the Ios draft, the guaranteed filling of the contact zone of the workpieces with the material of the transition element is not ensured over the entire cross-sectional area of the workpieces, in particular in the central part of the cross-section.

In the case when the embedment depth is greater than 1.0 from the amount of the allowance for the sag, it is guaranteed that the contact zone of the workpieces is filled with the material of the transition element over the entire cross-sectional area of the workpieces, but the volume of the material used for the manufacture of the transition element increases unreasonably, productivity decreases , the effectiveness of the proposed useful model decreases.

The value of the allowance for the Ioss deposit is set before welding on the basis of literature data - reference books, scientific articles or as a result of previous experiments when welding workpieces of specified sizes from specific materials to be welded.

The technical essence of the proposed useful model is explained by the given graphic materials, which show: options for making recesses in blanks for placing a transitional element in it, where fig. 1 - a diagram of the deepening of a conical shape in a workpiece of a continuous section, to, No, o; - recess dimensions, Y - workpiece diameter; Fig. 2 - a photograph of a made depression of a conical shape in a steel blank of a solid cross-section; Fig. C - the scheme of the recess of a cylindrical shape in the workpiece of tubular section, Yuo, to, po - the dimensions of the recess 0, and - the dimensions of the workpiece; variants of the layout scheme of the workpieces before performing pressure welding with a transition element placed in the depressions, where Fig. 4 - the transition element is rigidly fixed in both blanks of solid section, Fig. 5 - the transition element is fixed in one of the blanks, Fig. 6 - the transition element is fixed in one of the tubular cross-section blanks; a combined welded joint of workpieces made of steel 20 with a diameter of 20 mm, obtained through a transition element made of austenitic stainless steel 12X18H10T with a microcrystalline structure according to the layout of the workpieces shown in fig. 4, where Fig. 7 - macrostructure of the cross-section of the combined welded joint, Fig. 8 - panorama of the microstructure of the joint zone; a combined welded joint of blanks made of steel 20 with a diameter of 20 mm obtained through a transitional element of austenitic stainless steel 12X18N10T with a microcrystalline structure according to the layout of the blanks shown in Fig. 5, where fig. 9 -

macrostructure of the cross section of the combined welded joint, Fig. 9 - panorama of the microstructure of the connection zone.

The proposed useful model can be better understood from the following examples.

Examples of implementation of a useful model

Experiments were carried out on joining blanks made of structural steel 20 with a diameter of 20 mm (cross-sectional area 53-314 mm") by friction welding at the following modes: rotation frequency n-16.6 s", heating pressure Rie-50 MPa, forging pressure Ryair-100 MPa. To obtain high-quality welded joints, the allowance for sediment should be Ios - 3.5 mm Friction welding.

Directory / V.K. Lebedev, I.A. Chernenko, V.I. Bill et al. - L.: Mashinostroenie, 1987.-236 p. |

It is known that during direct pressure welding of steel 20 due to a change in the texture of the material and the formation of a narrow layer of metal in the joint zone with impact strength indicators significantly lower (several times) than the indicators of the base metal. Although the strength indicators of welded joints can be at the level of the main material, this fact makes it impossible to use such welded joints during operation under conditions of shock loads.

According to the proposed useful model, before welding, in the center of the cross-section of each of the workpieces, coaxially to its axis, a cone-shaped recess was made with a depth determined from the range (0.1-1.0) of the Ioss value. The cross-sectional area of the Ozall recess was determined from the range (0.05-0.5) from the value of 53. In the recesses of the blanks made by mechanical processing on a lathe, their surface levels were rigidly fixed with a transition element made of 12X18N10T steel with a microcrystalline structure. In this case, the transition element was fixed by the method of welding with a non-fusible electrode in a protective inert gas, although other methods of fixing by welding, surfacing, spraying, and mechanical fastening can be used. After that, friction welding was carried out with a specified allowance for the workpieces' deposit according to the diagrams shown in Fig. 4 and fig. 5.

Example 1. Friction welding according to the scheme shown in fig. 4.

The results of experiments on friction welding of workpieces made of steel 20 through a transition element made of steel 12X18N10T with a microcrystalline structure, fixed in both workpieces to be welded, are shown in table. 1.

The results of the study of the macro- and microstructure of the welded joint, obtained with the parameters of the experiment given in item 7 of Table 1, are presented, respectively, in fig. 7 and fig. 8. As can be seen, the welded joint of steel blanks 20 is formed through a transition element made of 12X18N10T steel, the thickness of which in the cross section is 0.3...1.5 mm. During mechanical tests of samples of welded joints for strength and impact toughness, results were obtained above the level of indicators for the base metal of steel 20, which became possible due to the formation of a welded joint through a transition element, the material of which has mechanical properties that exceed the corresponding indicators of the material blanks

Table 1

The recess and the transition element are fixed in both workpieces to be welded and the recess Results of experiments n/p Po, mm

Overall, MM

It is not ensured that the contact zone of the workpieces is filled with the material of the transitional element according to

ОЗагл«0.05 53 У - - 1 (14.0) о« 0.1 Ios (0.25) of the entire cross-sectional area of the workpieces, in particular in the " central and partially in the peripheral part of the cross-section

The filling of the zone / contact of the blanks with the material of the transitional element is ensured

Zzaly 20.5. 33 of the entire cross-sectional area of the blanks, but 2 No » 1.0 Ios (3.5) : ' (180.0) the volume of the material used for the manufacture of the transition element increases unreasonably

Continuation of table 1

Mo Area Depth of immersion. n/p deepening by, MM Results of experiments

Zzagl, MM

Filling of the zone / contact is ensured

Ш blanks with the material of the transition element according to

Total -0.0545Й. 53 In - - -

With (1577) Ppo--0.1 Ios (0.35) of the entire cross-sectional area of the workpieces in the form of a thin "continuous layer of almost the same thickness of about 0.04 mm

Filling of the zone / contact is ensured

A Total -0.05 Sh 53 by--1.0 Ios (3.5) of blanks with the material of the transition element by (15.7) ohm oo, the entire cross-sectional area of the blanks in the form of a thin continuous layer with a thickness of 0.04-3.6 mm

Filling of the zone / contact is ensured

Total -0.5.YCZZ by 0.1 Ios (0.55) of blanks with the material of the transitional element by (157.0) ote To the entire cross-sectional area of the blanks in the form of a continuous layer with a thickness of 0.1-0.2 mm

Filling of the zone / contact is ensured

Total -0.5 DC "53 by -1.0 Ios (3.5) of blanks with the material of the transition element by (157.0) over the entire cross-sectional area of the blanks in the form of a continuous layer with a thickness of 1.2-2.6 mm

The filling of the zone / contact 7 Total -0.1 DC 1ZZ3 by -0.8 Ios (2.8) of the blanks with the material of the transition element by (31.4) of the swelling of the entire cross-sectional area of the blanks in the form of a continuous layer with a thickness of 0.3-1 .5 mm

Example 2. Friction welding with the scheme shown in fig. 4.

The results of experiments on friction welding of workpieces made of steel 20 through a transition element 5 of steel 12X18H10T with a microcrystalline structure, fixed in one of the workpieces to be welded, are shown in table. 2.

Table 2

The recess and the transition element are fixed in one of the workpieces to be welded

Mo Area Depth of immersion. n/p deepening by, Results of experiments

In general,

Filling of the contact zone is not ensured

Fzate0 05 85 blanks with the material of the transition element on the back, Z SHHA - . 1 (14.0) o« 0.1 Ios (0.25) of the entire cross-sectional area of the workpieces, in particular in the " central and partly in the peripheral part of the cross-section

The filling of the zone / contact of the blanks with the material of the transitional element is ensured

Zzaly 20.5. 33 of the entire cross-sectional area of the blanks, but 2 No » 1.0 Ios (3.5) : ' (180.0) the volume of the material used for the manufacture of the transition element increases unreasonably

Filling of the zone / contact is ensured

Ш blanks with the material of the transition element according to

Total -0.0545Й. 53 In - - -

With (1577) Ppo--0.1 Ios (0.35) of the entire cross-sectional area of the blanks in the form of a thin "continuous layer of almost the same thickness of about 0.02 mm

Filling of the zone / contact is ensured

A Total -0.05 Sh 53 by--1.0 Ios (3.5) of blanks with the material of the transition element by (15.7) over the entire cross-sectional area of the blanks in the form of a thin continuous layer with a thickness of 0.02-1.7 mm

Continuation of table 2

Mo Area Depth of immersion. n/p deepening by, Results of experiments

In general,

Filling of the zone / contact is ensured

Total -0.5 DC "53 by 0.1 Ios (0.55) of blanks with the material of the transition element by (157.0) over the entire cross-sectional area of the blanks in the form of a continuous layer with a thickness of 0.05-0.15 mm

Filling of the zone / contact is ensured

Total -0.5 DC "53 by--1.0 Ios (3.5) of blanks with the material of the transition element by (157.0) over the entire cross-sectional area of the blanks in the form of a continuous layer with a thickness of 0.6-1.4 mm

The filling of the zone / contact 7 Total -0.1 DC 1ZZ3 by -0.8 Ios (2.8) of the blanks with the material of the transition element by (31.4) is ensured by the swelling of the entire cross-sectional area of the blanks in the form of a continuous layer with a thickness of 0.1-0 .4 mm

The results of the study of the macro- and microstructure of the welded joint obtained under the parameters of the experiment given in point 7 of Table 2 are shown, respectively, in fig. 9 and fig. 10. As can be seen in Figure 5, the welded joint of steel blanks 20 is formed through a transition element made of 12X18N10T steel, the thickness of which in the cross section is 0.1...0.4 mm. As in example 1, during mechanical tests of samples of welded joints for strength and impact toughness, the result was higher than the level of indicators for the base metal of steel 20.

The obtained results indicate the achievement of the result, which is the task of the proposed useful model - increasing the efficiency and simplifying the method of manufacturing a combined welded joint of two blanks through a transition element, and achieving the technical result - the formation of a zone of a combined joint with an intermediate element, the thickness of which varies according to cross-section of blanks.

Claims (3)

USEFUL MODEL FORMULA 1. The method of pressure welding of products made of homogeneous and dissimilar metal materials, in which at least one of the workpieces to be welded is connected to a transition element through which welding is performed, the welding process is carried out until the specified allowance for the deposit Iss is reached, which is distinguished by the fact that previously before welding in the center of the cross-section of at least one of the workpieces, coaxial to its axis, a recess is made, the area of which is (0.05-0.53 of the area of the cross-section of the workpiece, and the depth is (0.1-1.0) of the value of the axes, in the recess rigidly fix the transitional element of the surface level of the workpiece to be welded, after that weld the workpieces. 2. The method according to claim 1, which differs in that the recess and transition element are given the volume and shapes that coincide, and the shape is chosen from the series: cone, hemisphere, cylinder, prism. 3. The method according to claim 1, which is characterized by the fact that a material with a structure selected from the following is used as a transition element: microcrystalline, submicrocrystalline, nanocrystalline structure. kn i dk pu PZHYUTI i PE OT TU mon nn nn cha o Kolin nn t Fig: 1