RU2718599C1 - Method of reduction and simultaneous hardening of parts from sheet steel subjected to abrasive wear during operation (versions) - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to a method of reduction and simultaneous hardening of parts made from sheet steel subject to various types of abrasive wear depending on conditions of external action. Proposed method comprises removal of worn-out part of part and its replacement with separate segment made of sheet material and its attachment to rest part by permanent joint. According to one of the versions of the method, a segment with a pre-made groove is provided, which is attached to the restored part provided with a pre-made tenon. Hardening is performed by electro-erosion alloying till achieving the specified hardness of the segment. Prior to manufacturing of permanent connection of recovered part and segment of segment groove surface is coated with metal-polymer material. According to the second version, a segment with a pre-made tenon is provided, which is attached to the restored part provided with a previously made groove.

EFFECT: technical result is the absence of buckling, high hardness and wear resistance of reconditioned and hardened parts in conditions of intense abrasive wear, possibility of using wear-resistant metals as a reducing material with any degree of weldability, low power consumption and environmental safety.

18 cl, 22 dwg

Description

The invention relates to the field of mechanical engineering and machine repair, in particular to the restoration and simultaneous hardening of parts made of sheet steel, which are subject to various types of abrasive wear, depending on environmental conditions.

Spherical discs as the working bodies of implements intended for tillage are widely used on tillage machines such as plows, cultivators, seeders, harrows, potato planters, etc. The working bodies of tillage machines work in a soil environment, which is a strong loose abrasive. Under the influence of this medium, the blade of the disk quickly changes its shape, which leads to its blunting and loss of performance. [Shovkoplyas A.B. Disk working bodies of harrows: manufacturing and restoration technologies // Forestry magazine 1/2016. - Technology. Cars and equipment. C. 203-211.]

Industrial enterprises that use centrifuges, pumping and compressor equipment in their production process are faced with the need to protect during operation or repair of screw surfaces of centrifuge screws made of sheet metal and subjected to waterjet wear during repair. Sand contained in the sediment, not retained by sand traps, is the main cause of wear of centrifuge augers. Screws made of X18H10T steel wear out significantly after 1.5-3 thousand hours of operation. Since the cost of the screw is quite high (30% of the cost of the centrifuge), it is practiced to periodically replace screws that are restored under factory conditions [Operation of water supply, sewage and gas supply systems. Directory. Compiled by: V.D. Dmitriev, D.A. Koroviy, A.I. Korablev, G.P. Medvedev, B.G. Mishukov, M.P. Naumov, G.S. Chistova // Stroyizdat, Leningrad Branch, 1988, 384 s].

An equally important problem is the protection of machine parts and assemblies from gas-abrasive wear. So, after some time in a dusty stream, any initial profile of the inlet edge of the impeller blade of the centrifugal compressor turns into a pointed one. The blades of blowing machines are usually made from sheet metal [Livshits S.P. High-pressure centrifugal-type blowing machines. - L.: Mechanical Engineering, 1976.- 295 s].

Modern repair technologies have a sufficient number of ways to protect parts from abrasive wear: hard-alloy surfacing, gas-plasma spraying with hard-alloy powders, welding of individual segments with deposited surfacing in a vacuum with a composite material such as stellite, brazing of carbide plates directly on the wearing surface, etc. They are used as in the manufacture , and when repairing equipment. Each method has its advantages and disadvantages. One of the main disadvantages of such repair technologies as surfacing, brazing, gas-plasma spraying, welding, etc., is their negative impact on the environment.

Traditionally, when repairing screws, worn sections of the blades are replaced by separate segments, which are welded to the surviving surfaces. For example, during the repair of a centrifuge, grade OGSh-631K-02, which failed at the wastewater treatment facilities that are part of the Gorvodokanal GKP in Sumy, coatings were applied to individual segments, which were then pattern-welded to the surfaces of the screw. The segments, like the screw, were made of stainless steel 12X18H10T [Sarzhanov OA, Sarzhanov B.O. An analysis of the repair of essential parts of centrifuges for old water. Newsletter of the Sumy National Agrarian University. Seria “Mechanization and automation of viral processing processes”, issue 10/3 (31), 2016. - P. 58-62].

The disadvantage of this repair method is the significant complexity and high cost of coating, as well as the negative impact on the environment of the method of attaching segments to the worn surface of the screw by welding.

An example of a spherical disk as the working body of tools designed for tillage is the plow body blade.

Known design of the blade of the plow body, suggesting its restoration by welding by arc welding a segment that compensates for wear in a previously removed worn area of the blade. The segment is preliminarily subjected to heat treatment to a hardness of 50 ... 60 HRC over its entire depth. To ensure the necessary mechanical properties of the restored blade, surfacing of the weld area is performed [RF Patent for Utility Model No. 92823, V23K 9/04, publ. in B.I. No. 10, 2010].

However, the manufacture of a segment used to compensate for blade wear is associated with a number of difficulties. The main one is that it is subjected to heat treatment to obtain a given hardness of the segment. As a result, it becomes very difficult to maintain the required radius of curvature of a segment having a sufficiently large area due to its warping during heat treatment, which, among other things, negatively affects the environment.

Closest to the proposed method in terms of technical nature and the achieved result is a method of restoring and hardening the blade of the plow body, including removing the worn out part of the blade, ensuring the presence of a compensating wear profile section, welding it on the working side of the surface of the blade, and the size of the segment is selected based on the condition the location of the weld outside the area of intensive wear of the blade, and surfacing in the field of restoration of reinforcing rollers from a wear-resistant electrode material iala. Moreover, the reinforcing rollers are located perpendicular to the movement of the soil at a distance of 20 mm from each other, with their exit into the zone of the expected radial wear of the blade [RF Patent 2533957, V23P 6/00, A01B 15/04, publ. in B.I. No. 33, 2014 - prototype].

The disadvantage of this method is the strong thermal effect during surfacing of reinforcing wear-resistant rollers, because surfacing occurs with deep penetration of the base metal. This leads to warping of restored and hardened dumps. In addition, the method does not provide high indicators of wear resistance and resource of restored and hardened dumps of plow bodies during their operation on soils with high wear ability, especially sandy and sandy loam.

In this case, the use of arc welding during reconstruction involves:

- the impossibility of using as a material during recovery: metals with satisfactory weldability, when the welded metal is preheated to prevent cracks, and is subjected to heat treatment after welding; metals with limited weldability, when steel is prone to cracking and is preliminarily subjected to heat treatment, as well as heat treated after welding; metals with poor weldability, when the metal has a tendency to crack, and welding is performed with preliminary heat treatment, while heating is also carried out after welding;

the use of special welding converters (rectifiers, inverters) and welding transformers;

- high power consumption;

- the dependence of the quality of the joints on the qualifications of the welder;

- the complexity of the technology and the need for control at all its stages;

- harmful conditions of the welding process for others.

The basis of the invention the task:

- increase the durability of the restored and hardened parts made of sheet steel during their operation in environments with high wear ability;

- the absence of warpage, as well as increasing the hardness and wear resistance of the restored and hardened parts in conditions of intense abrasive wear;

- the possibility of using wear-resistant metals with any degree of weldability as a material in the conduct of the recovery process;

- low power consumption;

- environmental Safety.

The stated technical problem is solved by creating a method for the restoration and simultaneous hardening of parts made of sheet steel and subjected to abrasive wear during operation, which, like the prototype, includes removing the worn part of the part and replacing it with a separate segment, also made of sheet material, and connecting it with a restored part is an integral connection, but in which, in accordance with one of the variants of the claimed technical solution, a segment is provided pre-made groove, which is attached to the restored part, equipped with a pre-made spike, while the hardening of the restored part is carried out by the method of electroerosive alloying (EEL) until the specified hardness of the segment is achieved, and before creating an integral connection of the restored part and the segment of the surface of the groove of the segment, they are coated with a metal-polymer material (MPM ) In this case, the spike of the restored part is inserted into the groove of the segment by press fit, and the installed segment is additionally fixed with rivets, screws or other fasteners. Moreover, segments reconstructed are joined both from the materials identical to the restored part and from materials different from it, for example, for a plow body blade made of 65 G steel, segments can be made of any steel resistant to abrasion: 70G, 45 , L53, etc.

Hardening of the segment surfaces can be carried out by applying the E15 coating method using electrodes made of T15K6 hard alloys, first sequentially at a discharge energy of W _p = 0.55 J, and then at W _p = 0.90 J, and MPM, previously reinforced, is applied to the T15K6 hard alloy coating powder in the form of a VK6 carbide mixture added to a two-component epoxy system filled with Loctite 3478 ferrosilicon at a reinforcing substance concentration of ~ 60%. In addition, hardening of the surfaces of the segment can be carried out by stepwise coating by EEL cementation, reducing at each stage the discharge energy in the range from W _p = 6.8 J to W _p = 3.9 J.

In accordance with the second embodiment of the claimed technical solution, a segment with a preformed spike is provided, which is attached to the restored part provided with a preformed groove, while the segment spike is inserted into the groove of the restored part according to a sliding fit.

In addition, both in the first and in the second embodiment, the curved shape of the segment is obtained using the tooling used to make the curved shape of the restored part.

As parts subjected to abrasion during operation, the disks of tillage machines made of 65G sheet steel were used.

As parts subjected to abrasive wear during operation, centrifuge auger blades made of sheet steel 12X18H10T are used.

The technical result of the invention is the absence of warpage, as well as increasing the hardness and wear resistance of the restored and hardened parts in conditions of intense abrasive wear; the possibility of using wear-resistant metals with any degree of weldability as a reducing material; low power consumption and, not least, environmental safety.

Hardening of the segment surfaces by EEL cementation (CEEL) at a discharge energy of Wp = 6.8 J with a productivity of T = 0.5 cm ² / min provides a hardness of HRC 55-65.

Hardening of the surface of the segment by applying the T15K6 hard alloy electrodes by the EEL method sequentially at a discharge energy of W _p = 0.55 J and then at W _p = 0.90 J provides 100% continuity, the thickness of the increment layer, 0.12 mm , surface roughness Rz = 37 μm.

Application of the metal-polymer material (MPM) onto the formed coating, prepared using powder as a VK6 carbide mixture as reinforcing material, which is added in small portions to a two-component epoxy system filled with Loctite 3478 grade ferrosilicon, at a concentration of reinforcing agent of ~ 60%, it provides a segment with a higher degree of hardening achieved in an environmentally friendly way.

The following is a description of the claimed technical solution is presented with reference to illustrations of examples of specific implementation of the method.

In FIG. 1 shows a disk working body of a tillage machine subjected to abrasion during operation;

in FIG. 2 shows a section along aa of the disk working member shown in FIG. one;

in FIG. 3 is an enlarged view of a place B in FIG. 2 with blade sharpening at an angle α;

in FIG. 4, FIG. 5 shows the shape of a groove in a segment of a disk working body in FIG. one;

in FIG. 6, FIG. 7 shows the spike shapes in the disk tool in FIG. one;

in FIG. 8 shows a manufacturing diagram of segments;

in FIG. 9, FIG. 10 is a diagram of a segment fixation;

in FIG. 11 shows a spike and sharpening segment;

in FIG. 12 - a disk with grooves for segments .;

in FIG. 13 shows a restored disc harrow assembly;

in FIG. 14 shows a section of a screw with worn out places;

in FIG. 15, FIG. 16 shows a worn surface of auger blades reconstructed in a conventional manner;

in FIG. 17, FIG. 18 shows a groove in a segment and a spike in a blade of a centrifuge screw, respectively;

in FIG. 19 shows the structure of steel 12Kh18N10T after a sequential EEL with T15K6 hard alloy at W _p = 0.55 J and W _p = 0.90 J;

in FIG. 20 - the structure of steel 12X18H10T after serial EEL with the T15K6 + MPM hard alloy;

in FIG. 21 shows the microhardness distribution of the formed coatings as they deepen from the surface: 1 - by a sequential EEL with a T15K6 hard alloy at W _p = 0.55 J and W _p = 0.90 J; 2 - sequential EEL with a hard alloy T15K6 + MPM;

in FIG. 22 shows a centrifuge screw with a blade restored by the present method.

Restored the worn surface of the disk working body (Fig. 1) made of sheet steel 65G 6 mm thick. The worn surface of the disk (Fig. 2, Fig. 3) was machined both cleanly and on the petals, depending on the shape of the groove in the segment (Fig. 4, Fig. 5), spikes were made (Fig. 6, Fig. 7).

To obtain a segment on a lathe, a technological disk with a predetermined shape groove (Fig. 4, Fig. 5) and sharpenings on the outer diameter at an angle a, like the finished product (Fig. 2), were made from a 65G steel sheet with a thickness of 12 mm and a hardness of HRC 25. (B), Fig. 3). The technological disk with a groove was cut on a milling machine into separate segments 1 (Fig. 8). In FIG. 9, FIG. 10 shows a segment fixation scheme. When mounting a segment on a restored disk, the walls of the segment groove were unbent to a size that allows a disk spike to be inserted into it, and MPM was applied to its interface to the spike, the disk spike was inserted into the segment groove and the groove walls were compressed into the lock, forming a press fit the connection was fixed using additional fasteners (Fig. 9, Fig. 10), CEEL of the side walls of the groove having the initial hardness of HRC 25 at discharge energy Wp = 6.8 J with a productivity of T = 2.0 cm ² / min was carried out, increasing hardness up to HRC 57, rovodili Tseel segment surface located below the side walls of the recess and above honed surface having an initial hardness of HRC 25 at a discharge energy Wp = 6,8 J performance T = 0.5 cm ² / min, while increasing the hardness to 65 HRC.

In accordance with the second variant of the method of the claimed technical solution, depending on the size of the segment 1 with the spike 2 and the sharpening 3 (Fig. 11), the worn surface of the restored disk was machined as cleanly and through grooves 4 were made on the petals (Fig. 12).

In contrast to the first embodiment of the proposed method, in the second embodiment, segment 1 was manufactured with a spike 2 (Fig. 11). When mounting segment 1, the spike 2 of segment 1 (Fig. 11) was inserted into the groove 4 of the disk (Fig. 12), on a sliding fit, MPM was applied on the surface of the groove for mating with the spike, the surface of the segment was connected to the surface of the disk, holes were drilled through 5 ( Fig. 13) through the disk and segment 1, segment 1 was removed from the disk, the spike 2 of segment 1 was inserted into the groove of the disk and the connection was fixed with rivets or screws, CEEL of the segment and the adjacent surface of the disk were carried out at a discharge energy of Wp = 6.8 J s productivity T = 0.5 cm ² / min to obtain a hardness of HRC 55-60.

In FIG. 4 schematically shows a portion of a centrifuge screw with worn blades. Traditionally, when repairing screws, the worn sections of the blades (Fig. 15, Fig. 16) were replaced by separate segments, which were welded to the surviving surfaces. The segments, like the screw, were made of stainless steel 12X18H10T.

The use of the proposed method for the repair and restoration of worn blades of centrifuge screws turned out to be quite effective and appropriate, in particular, from the point of view of environmental impact.

на корисну модель №131805, МПК В23Н 5/02. Cnociб вiдновлення зношених поверхонь деталей машин з

сталi / В.Б. Тарельник, В.С. Марцинковський, О.П. Гапонова, С.В. Коноплянченко, Б.О. Саржанов / Опубл. 25.01.2019, Бюл. №2. - 21 с.], на сформированное покрытие наносили металополимерный материал (МПМ). В качестве армирующего материала при создании МПМ использовали порошок в виде твердосплавной смеси ВК6, который небольшими порциями добавляли в двухкомпонентную эпоксидную систему, наполненную ферросиликоном марки Loctite 3478, и тщательно перемешивали. Концентрация армирующего вещества составляла ~ 60%. Дальнейшее увеличение концентрации порошка ВК6 в металополимерной смеси усложняет перемешивание и не обеспечивает необходимого смачивания частиц твердосплавной смеси полимером. Полученную смесь наносили на сформированное методом ЭЭЛ покрытие из твердого сплава Т15К6.The worn surface of the auger blades made of 12X18H10 t sheet steel with a thickness of 6 mm was machined as clean and, depending on the size of the groove in the segment (Fig. 17), spikes were made (Fig. 18). Segments 50 × 50 × 12 mm in size were made of 12Kh18N10 t steel sheet with a thickness of 12 mm and a hardness of HRC 20. When mounting a segment on the auger blades, the groove walls were unbent until a spike was inserted on the auger blades, while before assembly on the groove surface, mating with with a spike, MPM was applied, a spike on the screws of the screw was inserted into the groove of the segment and the walls of the groove were squeezed into the lock, forming a press fit connection, the connection was fixed using additional fasteners (rivets, screws, etc.), the segment surfaces were strengthened by applying electrospark alloying (EEL) coating with electrodes made of T15K6 hard alloy sequentially at a discharge energy of W _p = 0.55 J, and then at W _p = 0.90 J. Sequential formation of a coating of T15K6 hard alloy with W _p = 0.55 and 0.90 J provides 100% continuity. The thickness of the increment layer, measured with a micrometer on individual protrusions, reached 0.12 mm, while the surface roughness was Rz = 37 μm. [Ukrainian patent for cinnamon model No. 115676, IPC V23H 5/00. Knobi vnovlennennya znoshnih on top of metal parts / V. B. Tarelnik, V.S. Martsinkovsky, O.G. Pavlov / Publ. 04/25/2017, Bull. Number 8. - 15 s]. According to [Patent

for cinnamon, model No. 131805, IPC V23H 5/02. Knoci b vosnovlennya znoshy on top of machine parts with

steel / V.B. Tarelnik, V.S. Marcinkowski, O.P. Gaponova, S.V. Konoplyanchenko, B.O. Sarzhanov / Publ. 01/25/2019, Bull. No. 2. - 21 p.], Metal-polymer material (MPM) was applied to the formed coating. Powder in the form of VK6 carbide mixture was used as the reinforcing material when creating the MPM, which was added in small portions to a two-component epoxy system filled with Loctite 3478 ferrosilicon and mixed thoroughly. The concentration of the reinforcing substance was ~ 60%. A further increase in the concentration of VK6 powder in the metal-polymer mixture complicates mixing and does not provide the necessary wetting of the particles of the carbide mixture with the polymer. The resulting mixture was applied onto a T15K6 hard alloy formed by the EEL method.

In FIG. 19, FIG. Figure 20 shows the structures of samples of 12Kh18N10T steel after a sequential EEL at W _p = 0.55 J and W _p = 0.90 J with a T15K6 hard alloy, also a sequential EEL with a T15K6 hard alloy according to the indicated modes and applying MPM, respectively. Microstructural analysis showed that after the EHE of steel 12X18H10T by hard alloy, the structure of the surface layer consists of three zones, FIG. 19. On the surface there is a zone up to 50 microns thick, having a darker color, the microhardness of which is in the range of 5000-5400 MPa. FIG. 21, (curve 1). As the metal moves deeper into the surface from the surface, a transition zone is located, the microhardness of which gradually decreases and, at a depth of ~ 70 μm, corresponds to the microhardness of the base. As studies have shown, coatings obtained by EEL technology with hard alloy and MPM deposition consist of 4 zones, FIG. 20. A darker zone up to 120 microns thick is formed on the surface, the microhardness of which is in the range of 6200-9200 MPa. Under it is a light colored zone up to 90 microns thick, the microhardness of which is about 3200 MPa. As you move away from the surface, the microhardness gradually decreases, and at a depth of 280 μm corresponds to the microhardness of the base, FIG. 21 (curve 2).

In FIG. 22 shows a centrifuge screw with blades reconstructed using the proposed technology.

Similarly, a centrifuge screw can be restored in accordance with a second embodiment of the inventive method, in which segments can be made with spikes.

Claims (18)

1. The method of recovery with the simultaneous hardening of a part made of sheet steel subjected to abrasive wear during operation, including the removal of the worn part of the part, replacing it with a segment made of sheet material, and joining it with an integral connection to the restored part, characterized in that on the restored part spikes are preliminarily performed, which are attached to the segment with preformed grooves, after which the restoring part is hardened by the elemental method troerozionnogo doping to achieve a given hardness segment, wherein prior to creating the permanent connection parts recoverable segment and mating surfaces coated with metal-polymer material. 2. The method according to p. 1, characterized in that the spike of the restored part is inserted into the groove of the segment by press fit, and the segment is additionally fixed with fasteners. 3. The method according to p. 1 or 2, characterized in that the segment is made from the same with the restored part, and materials different from it. 4. The method according to p. 1, characterized in that the hardening of the surfaces of the segment is carried out by stepwise coating by cementation of electroerosive alloying, reducing at each stage the discharge energy in the range from W _p = 3.9 J to W _{p =} 6.8 J. 5. The method according to p. 1, characterized in that the hardening of the surfaces of the segment is carried out by applying a method of electroerosive alloying of the coating with a T15K6 hard alloy electrode sequentially first at a discharge energy of W _p = 0.55 J and then at W _p = 0.90 J. 6. The method according to p. 5, characterized in that on the coating of the T15K6 hard alloy, MPM is applied, pre-reinforced with powder in the form of a VK6 carbide mixture, added to a two-component epoxy system filled with Loctite 3478 ferro-silicone at a concentration of reinforcing substance of 60%. 7. The method according to p. 1, characterized in that the segment is made of a curved shape, using the technological equipment used to make a curved shape of the restored part. 8. The method according to p. 1 or 4, characterized in that the parts subjected to abrasive wear during operation are the disks of tillage machines made of sheet steel 65G. 9. The method according to any one of paragraphs. 1, 5, 6, characterized in that the parts subjected to abrasive wear during operation are centrifuge auger blades made of sheet steel 12X18H10T. 10. The method of restoration with simultaneous hardening of a part made of sheet steel subjected to abrasive wear during operation, including the removal of the worn part of the part, replacing it with a segment made of sheet material, and connecting it to the part being restored with an integral connection, characterized in that they provide a segment with a pre-made spike, which is attached to the restored part with a groove pre-made in it, after which the restoration is hardened of the workpiece by the method of electroerosive alloying until the specified hardness of the segment is achieved, and before creating an indivisible connection of the reconditioned part and the segment, the mating surfaces are coated with a metal-polymer material. 11. The method according to p. 10, characterized in that the spike of the segment is inserted into the groove of the restored part by sliding fit, and the installed segment is additionally fixed with fasteners, for example rivets or screws. 12. The method according to p. 10 or 11, characterized in that a segment is made of the part to be restored that is made of the same materials as the part being restored and that are different from it. 13. The method according to p. 10, characterized in that the hardening of the surfaces of the segment is carried out by phased coating by the method of cementation of electroerosive alloying, reducing at each stage the discharge energy in the range from W _p = 3.9 J to W _p = 6.8 J. 14. The method according to p. 10, characterized in that the hardening of the surfaces of the segment is carried out by applying a method of electroerosive alloying of the coating with T15K6 hard alloy electrodes sequentially first at a discharge energy of W _p = 0.55 J and then at W _p = 0.90 J. 15. The method according to p. 14, characterized in that a metal polymer material pre-reinforced with a powder in the form of a VK6 carbide mixture added to a two-component epoxy system filled with Loctite 3478 grade ferrosilicon at a concentration of reinforcing substance of 60% is applied to the T15K6 carbide coating. 16. The method according to p. 10, characterized in that the curved shape of the segment is obtained using technological equipment used to make the curved shape of the restored part. 17. The method according to p. 10 or 13, characterized in that as parts subjected to abrasive wear during operation, the disks of tillage machines made of sheet steel 65G are used. 18. The method according to any one of paragraphs. 10, 14, 15, characterized in that as parts subjected to abrasive wear during operation, centrifuge auger blades made of sheet steel 12X18H10T are used.

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