Method for frictionally depositing a metal part

Abstract

The application relates to a friction build-up welding repair method for metal parts and relates to the technical field of welding repair of metal materials. The main technical scheme is that in the process of adopting a raw material rod to perform friction build-up welding treatment on a metal part, a set type of cooling medium is applied to the raw material rod and the metal part in a set mode, heat generated in the friction build-up welding process is timely conducted, excessive softening and deformation of the raw material rod are inhibited, and the top forging pressure and the friction force of the raw material rod acting on the surface of the metal part are improved. The application is mainly used for improving the stability of the contact friction force and the top forging pressure of the raw material rod and the surface of the metal part in the friction build-up welding process, thereby promoting metallurgical combination of a build-up welding layer and a metal part interface, and thereby solving the problems of poor interface combination, poor surface forming quality, high repair cost and low material utilization rate of the existing friction build-up welding repair.

Description

Technical Field

[0001] This invention relates to the field of metal material welding repair technology, and in particular to a friction welding repair method for metal parts. Background Technology

[0002] Friction surfacing is an advanced solid-state additive manufacturing technology widely used for the repair and surface modification of metal parts. The basic principle of friction surfacing is to utilize frictional heat and mechanical pressure to induce thermoplastic deformation between a raw material rod (square or circular cross-section) and the surface of a metal part, thereby achieving material transfer and the formation of a weld overlay. During friction surfacing, the raw material rod contacts the surface of the metal part under rotation and axial pressure. The heat generated by friction causes the material at the contact surface to reach a thermoplastic state (a viscoplastic deformation layer forms near the center of the rod). At this point, upsetting pressure is applied, causing the viscoplastic deformation layer to undergo plastic deformation and form a metallurgical bond with the surface of the metal part. Meanwhile, the edge material flows outwards under the influence of high temperature and pressure, forming redundant creases. As the raw material rod moves, the weld overlay gradually forms.

[0003] Friction welding repair relies heavily on the formation of stable and sufficient contact friction and upsetting pressure between the raw material bar and the metal part surface. This ensures stable friction and plastic deformation heat generation, guaranteeing a smooth, uniform weld layer with good interfacial bonding. However, in actual welding processes, the raw material bar is continuously plasticized, transferred, and consumed under intense deformation and high-speed rotation. This dynamic process means that the contact friction and upsetting pressure between the raw material bar and the metal part surface are difficult to control stably. Furthermore, compared to the raw material bar, the metal part is generally larger, while the raw material bar is slender with a small heat transfer area. This means that the heat in the raw material bar is difficult to dissipate fully, causing the temperature to gradually rise and accumulate. This leads to excessive softening and deformation of the raw material bar, severely reducing its upsetting pressure and friction with the metal part surface.

[0004] Due to the uneven input of heat and pressure, the raw material bar cannot achieve complete contact with the surface of the metal part, resulting in low interfacial bonding strength and a relatively small effective bonding area between the weld overlay and the metal part. This means that the repaired part may have incomplete bonding or insufficient bonding strength in some areas. When the part is subjected to high stress or complex loads, it is prone to cracking or peeling at the interface, thus affecting the repair effect and service life of the part, and reducing the overall performance and reliability of the part.

[0005] Furthermore, the unstable transfer of heat and force in the raw material bar leads to unstable shearing and delamination between the viscoplastic deformation layer and the weld overlay layer. This results in poor surface forming quality of the weld overlay layer, making it prone to defects such as ripples, unevenness, and cracks. These surface defects not only affect the appearance quality of the parts but can also become stress concentration points, reducing the fatigue strength and corrosion resistance of the parts. Poor surface forming quality makes it difficult to control the dimensional accuracy of the weld overlay layer. Repaired parts often require subsequent machining, such as milling and grinding, to restore the original dimensions and surface roughness requirements. This not only increases repair costs and time but may also lead to material waste and part deformation. Furthermore, the limited effective bonding area and poor surface forming quality mean that more raw material bars are needed to achieve the desired repair effect, further reducing material utilization. Summary of the Invention

[0006] In view of this, the present invention provides a friction welding repair method for metal parts, the main purpose of which is to improve the stability of the contact friction force between the raw material bar and the surface of the metal part and the upsetting pressure during the friction welding process, thereby promoting the metallurgical bonding between the weld layer and the metal part interface.

[0007] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0008] This invention provides a method for friction welding repair of metal parts. In the process of friction welding the metal parts with a raw material bar, a set type of cooling medium is applied to the raw material bar and the metal parts in a set manner to conduct the heat generated during the friction welding process in a timely manner, suppress the excessive softening and deformation of the raw material bar, and increase the upsetting pressure and friction force of the raw material bar on the surface of the metal parts.

[0009] Preferably, the cooling medium of the specified type includes any one of water, liquid nitrogen, and liquid carbon dioxide.

[0010] Preferably, the setting method includes: placing the raw material bar and the metal part in a cooling medium and performing friction welding.

[0011] Preferably, during the friction welding process: the metal part must be completely immersed in the cooling medium or the area to be repaired on the metal part must be immersed in the cooling medium; the depth to which the raw material bar is immersed in the cooling medium is at least twice the maximum cross-sectional dimension of the raw material bar.

[0012] Preferably, the cooling medium is contained in a cooling container;

[0013] Preferably, during the friction surfacing process, if the cooling medium is water, the temperature of the cooling medium in the cooling container must be controlled to be no higher than 50°C.

[0014] Preferably, the cooling container is provided with a cooling medium inlet and a cooling medium outlet; wherein, the cooling medium inlet is used to connect to a cooling medium delivery pipe and the cooling medium outlet is used to connect to a cooling medium discharge pipe;

[0015] Preferably, before the friction welding process, the cooling medium inlet is opened and the cooling medium is injected into the cooling container; when the cooling medium in the cooling container reaches a set volume, the cooling medium outlet is opened to continuously inject and discharge the cooling medium, so that the cooling medium in the cooling container is in a state of continuous flow and renewal; then, the friction welding process is performed.

[0016] Preferably, the injection flow rate of the cooling medium is not less than 1 liter / minute;

[0017] Preferably, the discharge flow rate of the cooling medium is not less than 1 liter / minute;

[0018] Preferably, the injection flow rate of the cooling medium is the same as the discharge flow rate of the cooling medium.

[0019] Preferably, the raw material rod is made of the same material as the metal part to be repaired.

[0020] Preferably, the friction welding repair method for the metal parts includes the following steps:

[0021] Assembly and positioning steps: Fix the metal parts in the cooling container, or place the part of the metal parts to be repaired in the cooling container;

[0022] Step of applying cooling medium: Injecting a set volume of cooling medium into the cooling container; preferably, the cooling medium in the cooling container is in a state of continuous flow and renewal;

[0023] Friction welding process: Clamp the raw material bar at the end of the welding machine spindle, and then use the raw material bar to perform friction welding on the metal parts.

[0024] Preferably, in the friction welding process step:

[0025] The raw material bar is rotated at a first rotational speed and moved towards the surface of the metal part. After the raw material bar comes into contact with the metal part and generates heat through friction, the raw material bar is pressed down and stopped for a certain period of time, causing the raw material bar and the metal part to locally heat up and soften, forming a viscoplastic deformation layer. Then, the raw material bar moves along the part to be repaired on the metal part at a set speed while rotating and pressing down, forming a weld overlay layer. During the movement of the raw material bar, the rotational speed needs to be controlled at a second rotational speed and the pressing speed at a set axial feed speed. After the surface of the part to be repaired is completely covered by the weld overlay layer, the raw material bar is moved away from the metal part and the rotation is stopped, completing the friction weld overlay.

[0026] Preferably, the downward pressing speed is 2-10 mm / min;

[0027] Preferably, the rotation stop time is 0-10 seconds.

[0028] Preferably, in the friction welding process step:

[0029] If the material of the raw material bar and the metal part is stainless steel, and the cooling medium is water, then: the first rotation speed is 500-1500 rpm, the second rotation speed is 500-1500 rpm, the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min;

[0030] If the raw material bar and metal parts are made of stainless steel, and the cooling medium is liquid carbon dioxide, then: the first rotational speed is 1000-2000 rpm, the second rotational speed is 1000-2000 rpm; the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min;

[0031] If the material of the raw material bar and the metal part is stainless steel, and the cooling medium is liquid nitrogen, then: the first rotational speed is 1500-3000 rpm, the second rotational speed is 1500-3000 rpm; the traveling speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min.

[0032] Compared with the prior art, the friction welding repair method for metal parts of the present invention has at least the following beneficial effects:

[0033] This invention provides a method for friction welding repair of metal parts. During the friction welding process of a raw material bar and a metal part, a specific type of cooling medium is applied to the raw material bar and the metal part in a predetermined manner to conduct away the heat generated during the friction welding process. This stabilizes the heat and pressure, thereby suppressing excessive temperature rise, softening, and deformation of the raw material bar. It also increases the upsetting pressure and friction force exerted by the raw material bar on the surface of the metal part, causing the viscoplastic deformation layer to transfer to the surface of the metal part. This promotes atomic diffusion and metallurgical bonding between the weld layer and the substrate surface, improving the interfacial bonding strength. Specifically, this invention limits the excessive plastic softening effect of the raw material bar by applying forced cooling, reducing the thickness of the viscoplastic deformation layer. This reduces redundant edge dimensions and weld layer thickness, improves the surface smoothness of the weld layer, reduces the amount of machining required after repair, saves materials and energy, and promotes cost reduction and efficiency improvement in the production process.

[0034] Furthermore, this embodiment of the invention provides a friction welding repair method for metal parts, which involves "placing the raw material rod and the metal part in a cooling medium and performing friction welding treatment" to apply a cooling effect to the raw material rod and the metal part. This method is simple and easy to implement, requiring only a cooling container. Further, to improve the cooling effect, during the friction welding process, it is necessary to ensure that "the metal part is completely immersed in the cooling medium or the area to be repaired on the metal part is immersed in the cooling medium; the depth of immersion of the raw material rod in the cooling medium is at least twice the maximum cross-sectional dimension of the raw material rod," and that "the cooling medium in the cooling container is in a state of continuous flow and renewal."

[0035] Furthermore, this embodiment of the invention provides a method for friction welding repair of metal parts. During the friction welding process, if the selected cooling medium is water, the temperature range of the cooling medium in the cooling container is controlled to be no higher than 50°C, so as to ensure that the heat generated during the welding process is carried away by the cooling medium in a timely manner.

[0036] Furthermore, the friction welding repair method for metal parts provided in this embodiment of the invention, in the friction welding process, matches the corresponding friction welding parameters according to the type of cooling medium. Specifically, if the material of the raw material bar and the metal part is stainless steel, and the cooling medium is water, then: the first rotational speed is 500-1500 rpm, the second rotational speed is 500-1500 rpm, the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min; if the material of the raw material bar and the metal part is stainless steel, and the cooling medium is water... For liquid carbon dioxide, the first rotational speed is 1000-2000 rpm, the second rotational speed is 1000-2000 rpm, the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min. If the raw material bar and metal part are made of stainless steel, and the cooling medium is liquid nitrogen, the first rotational speed is 1500-3000 rpm, the second rotational speed is 1500-3000 rpm, the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min. Here, the control of the above friction surfacing parameters and the matching of the cooling medium ensure appropriate welding heat input, resulting in a smooth and uniform surface of the final surfacing layer without obvious defects. The surfacing layer is relatively thin, its surface is almost flush with the surface of the metal part, and a clear repair zone is formed inside the metal part.

[0037] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0038] Figure 1 This is a cross-sectional schematic diagram of the friction welding assembly during the welding process under the action of a cooling medium in the friction welding repair method for metal parts provided in this embodiment of the invention. Figure 1 In the diagram, WD indicates the direction of travel of the raw material bar (welding direction), FD indicates the feed direction, and TD indicates the lateral movement direction (lateral translation direction).

[0039] Figure 2 This is a schematic diagram of the welding process of a friction-welded assembly under conditions without a cooling medium (i.e., in an atmospheric environment), as described in the prior art; wherein, in Figure 2 In the diagram, WD indicates the direction of travel of the raw material bar (welding direction), FD indicates the feed direction, and TD indicates the lateral movement direction (lateral translation direction).

[0040] Figure 3 This is a photograph of the upper surface of the weld overlay layer; among which, Figure 3 Figure (a) is a physical image of the upper surface of the weld overlay obtained in Example 1; Figure 3 Figure (b) is a photograph of the upper surface of the weld overlay obtained in Example 1;

[0041] Figure 4 This is a cross-sectional view of the weld overlay layer; among which, Figure 4 Figure (a) is a cross-sectional view of the weld overlay obtained in Example 1; Figure 4 Figure (b) is a cross-sectional view of the weld overlay obtained in Example 1;

[0042] Figure 5 This is a photograph of the upper surface of the weld overlay obtained in Comparative Example 2.

[0043] The reference numerals in the attached drawings are as follows: 1. Raw material bar; 11. Preheating layer; 12. Viscoplastic deformation layer; 13. Redundant rolled edge; 14. Shear interface; 2. Weld overlay layer; 3. Metal part; 4. Repair area; 5. Cooling medium; 6. Cooling container. Detailed Implementation

[0044] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0045] In existing technologies, such as Figure 2As shown, in the existing friction welding process, the heat in the raw material rod 1 is difficult to dissipate sufficiently, resulting in uneven heat and pressure input. The raw material rod 1 cannot achieve reliable contact with the surface of the metal part 3, leading to low interfacial bonding strength and a relatively small effective bonding area between the weld overlay layer 2 and the metal part 3. This affects the repair effect and service life of the part, reducing its overall performance and reliability. The inability to fully dissipate heat results in both the preheating layer 11 and the viscoplastic deformation layer 12 being relatively thick. The thicker viscoplastic deformation layer 12 forms unstable shear and delamination (forming a shear interface 14) between itself and the weld overlay layer 2, resulting in poor surface forming quality of the weld overlay layer, reduced fatigue strength and corrosion resistance, and increased repair costs.

[0046] This invention provides a friction welding repair method for metal parts. During the friction welding process, the contact friction between the raw material bar and the surface of the metal part and the stability of the upsetting pressure can be improved, thereby promoting the metallurgical bonding between the weld layer and the metal part interface. This solves the problems of poor interface bonding, poor surface forming quality, high repair cost and low material utilization in existing friction welding repair methods.

[0047] During the friction welding process, the heat generated by the frictional deformation of the raw material rod (with a square or circular cross-section) is concentrated in the viscoplastic deformation layer near the shear interface. This viscoplastic deformation layer then flows and transfers through heat conduction to the redundant rolled edge and the weld overlay layer. Through extensive research, the inventors have discovered that: Figure 1 As shown, when the cooling medium 5 (contained in the cooling container 6) is applied forcefully to the surfaces of the raw material bar 1 and the weld overlay layer 2, the heat in the raw material bar 1 is promptly removed, the surface temperature of the redundant crimp 13 decreases, and the fluidity of the plastic elastic layer of the redundant crimp 13 is restricted, preventing further crimp formation. As the temperature of the raw material bar 1 and the redundant crimp 13 decreases, more heat from the viscoplastic deformation layer 12 is transferred to the weld overlay layer 2 and the metal part 1 (the viscoplastic deformation layer 12 is formed at the bottom of the raw material bar, and the portion of the raw material bar adjacent to the viscoplastic deformation layer 12 is a preheated layer). Thanks to the timely removal of heat by the forced cooling medium, excessive heating, softening, and deformation in the raw material bar are suppressed, and the upsetting pressure acting on the surfaces of the weld overlay layer 13 and the metal part 3 increases.

[0048] Under conditions without forced cooling, such as Figure 2 As shown, during the welding process, the thickness of the weld overlay 2 and the redundant crimp 13 are significantly greater than those of the weld overlay formed under forced cooling conditions (see [reference]). Figure 1 and Figure 2 (Comparison). For example, Figure 1As shown, after forced cooling using the method of the present invention, the temperature of the raw material bar decreases, the upsetting force acting on the metal part increases, the viscoplastic deformation layer transfers to the surface of the metal part and its thickness decreases, and the thickness of the weld overlay layer decreases accordingly. Due to the transfer of high temperature and high pressure to the surface of the metal part, coupled with the increased friction caused by the increased upsetting force, the atomic diffusion and metallurgical bonding between the weld overlay layer and the surface of the metal part are more complete, and the interfacial bonding strength is improved. The weld overlay layer finally prepared by the present invention has a smooth and uniform surface shape without obvious defects, a small weld overlay layer thickness, and its surface is almost flush with the surface of the metal part, forming a clear repair zone 4 inside the metal part.

[0049] The main solutions of this invention are as follows:

[0050] On one hand, embodiments of the present invention provide a friction welding repair method for metal parts, wherein, during the friction welding process of the raw material bar and the metal part, a set type of cooling medium is applied to the raw material bar and the metal part in a set manner to conduct the heat generated during the friction welding process in a timely manner, suppress the excessive softening and deformation of the raw material bar, and increase the upsetting pressure and friction force of the raw material bar acting on the surface of the metal part.

[0051] It should be noted that the cooling medium must possess strong thermal conductivity to effectively dissipate the heat generated during the welding process. Preferably, the cooling medium includes, but is not limited to, substances with high thermal conductivity (far exceeding that of air), such as water, liquid nitrogen, and liquid carbon dioxide. Specifically, water has a temperature of 10-25°C, liquid carbon dioxide has a temperature of -37°C, and liquid nitrogen has a temperature of -196°C.

[0052] Preferably, the method (specific implementation) includes: placing the raw material bar and the metal part in a cooling medium for friction welding. Preferably, during the friction welding process, the metal part is completely immersed in the cooling medium; the depth of immersion of the raw material bar in the cooling medium is at least twice the maximum cross-sectional dimension of the raw material bar to ensure sufficient heat conduction.

[0053] It should be noted that the cooling medium can be applied in two ways:

[0054] 1) First method: External cooling medium

[0055] First, a cooling medium is injected into a cooling container, and then the raw material rod and metal part are placed inside the cooling container for friction welding. This method is suitable for small-sized metal parts that are easy to clamp and allow for off-site repair.

[0056] The volume of the cooling container should be large enough that the volume of the cooling medium is much larger than the volume of the raw material bar, and it should be able to ensure that the repaired area on the metal part to be repaired is completely immersed in the cooling medium. The depth of immersion of the raw material bar in the cooling medium should be at least twice the maximum cross-sectional dimension of the raw material bar. If the cooling medium is water, the temperature range of the cooling medium in the cooling container should be controlled to be no higher than 50°C. Otherwise, the heat generated during the welding process cannot be carried away by the cooling medium in time, the temperature of the cooling medium will continue to rise, the temperature in the raw material bar will continue to rise, and the pressure will decrease.

[0057] The cooling container should be equipped with a cooling medium inlet and a cooling medium outlet to allow the cooling medium to be injected into and discharged from the container. The cooling medium inlet connects to the cooling medium delivery pipe, and the cooling medium outlet connects to the cooling medium discharge pipe. Preferably, the delivery pipe and discharge pipe have a circular, square, or other hollow cross-section. The dimensions of the cooling medium inlet, outlet, delivery pipe, and discharge pipe should be consistent to ensure that the cooling medium is injected into and discharged from the cooling container at the same rate, thus maintaining a stable volume of cooling medium in the container. To ensure effective cooling, the flow rate of the cooling medium inlet and outlet should be no less than 1 liter per minute; otherwise, the heat generated during welding cannot be carried away by the cooling medium in time, causing the temperature of the cooling medium to rise continuously, leading to a continuous increase in the temperature of the raw material bar and a decrease in pressure.

[0058] In some implementations, if the part to be repaired is large and off-site repair is not allowed, local cooling can be used, that is, only the defective area of ​​the metal part to be repaired is cooled (specifically, the shape of the cooling container is customized according to the shape of the part to be repaired, it is placed on the part to be repaired, and the part in contact with the part is sealed). The size of the cooling container can be adjusted according to the size of the defect.

[0059] 2) The second type: The part being repaired is already in a cooling medium (usually water), so the friction welding repair process does not require additional cooling medium.

[0060] The metal part being repaired operates within a cooling medium, such as a submarine or its components. In this case, the forced cooling conditions described in the first type are automatically met: the volume of the cooling medium is much larger than the volume of the raw material bar, the metal part is completely immersed in the cooling medium, and the depth to which the raw material bar is immersed in the cooling medium is at least twice the maximum cross-sectional dimension of the raw material bar. This friction welding repair process does not require the application of additional cooling medium.

[0061] Preferably, the raw material bar is made of the same material as the metal part to be repaired; wherein the metal part to be repaired is repaired by friction welding of the raw material bar.

[0062] Preferably, embodiments of the present invention provide a method for friction welding repair of metal parts, comprising the following steps:

[0063] Assembly and positioning steps: Fix the metal part inside the cooling container, and position and assemble the cooling container with the welding machine platform to ensure that the metal part does not loosen during the friction welding process; or, place the part to be repaired on the metal part inside the cooling container. Preferably, in this step, if the metal part (the part to be repaired) itself is working in the cooling medium, it is only necessary to limit the position of the metal part to ensure that it does not loosen during the repair process.

[0064] Step 1: Applying cooling medium: Inject a predetermined volume of cooling medium into the cooling container. Preferably, in this step, the metal part is completely immersed in the cooling medium by injecting it into the cooling container, and the depth of immersion of the raw material bar in the cooling medium is at least twice the maximum cross-sectional dimension of the raw material bar. Once the liquid level of the injected cooling medium reaches the required volume, the cooling medium outlet of the cooling container is opened to discharge the cooling medium, and the flow rates of the cooling medium inlet and outlet are controlled to be consistent.

[0065] Friction welding process steps: The raw material bar is clamped at the end of the welding machine spindle, and then friction welding is performed on the metal part. Preferably, in this step, the raw material bar is clamped at the end of the welding machine spindle, and then the raw material bar is rotated at a first rotational speed while moving towards the surface of the metal part; after the raw material bar comes into contact with the metal part and generates heat through friction, the raw material bar is pressed down and then stopped (stopping time 0-10 seconds), so that the raw material bar and the metal part heat up and soften, forming a viscoplastic deformation layer; then, the raw material bar is rotated and pressed down while traveling along a set position on the metal part at a set speed to form a weld overlay layer; wherein, during the movement of the raw material bar, the rotational speed needs to be controlled at a second rotational speed and the pressing speed at a set axial feed speed; after the surface at the set position is completely covered by the weld overlay layer, the raw material bar is moved away from the metal part and the rotation is stopped, completing the friction welding; preferably, the set position is the target defect position (the part to be repaired) of the metal part.

[0066] Preferably, if the material of the raw material bar and the metal parts is stainless steel (e.g., 304 stainless steel, 304L stainless steel, 316 stainless steel, 316L stainless steel, 321 stainless steel) and the cooling medium is water, then: the first rotational speed is 500-1500 rpm, the second rotational speed is 500-1500 rpm, the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min.

[0067] If the raw material bar and metal parts are made of stainless steel (e.g., 304 stainless steel, 304L stainless steel, 316 stainless steel, 316L stainless steel, 321 stainless steel), and the cooling medium is liquid carbon dioxide, then: the first rotational speed is 1000-2000 rpm, the second rotational speed is 1000-2000 rpm; the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min;

[0068] If the raw material bar and metal parts are made of stainless steel (e.g., 304 stainless steel, 304L stainless steel, 316 stainless steel, 316L stainless steel, 321 stainless steel) and the cooling medium is liquid nitrogen, then: the first rotational speed is 1500-3000 rpm, the second rotational speed is 1500-3000 rpm; the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min.

[0069] Regarding the selection of the above-mentioned friction surfacing welding parameters, it should be noted that:

[0070] (1) The control of the above friction welding processing parameters and the matching of the type of cooling medium make the welding heat input appropriate. The surface of the final weld layer is flat and uniform with no obvious defects. The thickness of the weld layer is small, and the surface of the weld layer is almost flush with the surface of the metal part, forming an obvious repair area inside the metal part.

[0071] (2) Under cooling medium conditions, when the first rotation speed and the second rotation speed are less than 500 rpm, the travel speed of the raw material bar is greater than 200 mm / min, and the axial feed speed is less than 5 mm / min: the welding heat input is insufficient, the raw material bar and the metal parts are difficult to soften, and the surface of the weld overlay is prone to defects such as ripples, unevenness, and cracks, and cannot be effectively bonded to the metal parts.

[0072] (3) Under cooling medium conditions, when the first rotation speed and the second rotation speed are higher than 3000 rpm, the travel speed is lower than 20 mm / min, the axial feed speed is higher than 100 mm / min, and the flow rate of the cooling medium is less than 1 liter / min: the welding heat input is too large, the temperature of the cooling medium rises, the temperature of the weld overlay and the raw material bar is too high, the heat accumulates excessively, the weld overlay exhibits spattering and collapse, the redundant edge curling is severe, the thickness of the weld overlay increases, the surface shows ripple defects, and the microstructure of the repaired area and the weld overlay grows compared with the original metal part.

[0073] (4) When the temperature of the selected cooling medium decreases, the first rotation speed and the second rotation speed should be increased accordingly to avoid the problem of insufficient welding heat input leading to a decrease in weld quality.

[0074] In another aspect, embodiments of the present invention provide a metal part repaired by friction surfacing, wherein the metal part to be repaired is subjected to friction surfacing treatment using any of the above-described friction surfacing methods to obtain the metal part repaired by friction surfacing; preferably, the surface of the surfacing layer on the metal part repaired by friction surfacing is flat, without delamination, grooves and warping defects, and there are no obvious burrs and curls on the sides, and the microstructure of the repaired area and the surfacing layer does not grow compared with the original metal part.

[0075] The present invention will be further illustrated below with specific embodiments:

[0076] Example 1

[0077] In this embodiment, a 304L bar with a diameter of 20 mm and a length of 150 mm is selected as the raw material bar, and a 304L stainless steel plate with a thickness of 12 mm is selected as the metal part. Friction welding is performed on the surface of the metal part. Tap water is used as the cooling medium. The main steps are as follows:

[0078] Assembly and positioning steps: First, fix the metal parts in the steel water tank, and then position and assemble the water tank with the welding machine platform to ensure that the metal parts do not loosen during the repair process.

[0079] Applying cooling medium: Inject water (temperature 15℃) into the water tank through the inlet, so that the metal part is completely immersed in the water. When the water level is 50 mm above the surface of the metal part (the depth of the raw material rod immersed in the water during the friction welding process is 2.5 times the diameter of the raw material rod), open the outlet of the water tank to drain the water, and control the flow rate of the inlet and outlet to be 2 liters / minute.

[0080] Friction cladding process: First, the raw material bar is clamped at the end of the welding machine spindle, then rotated at 1000 rpm and brought close to the surface of the metal part. After the raw material bar contacts the metal part, it is pressed down by 2 mm (pressing speed is 2 mm / min, and it is paused for 1 second after pressing down), causing the raw material bar and the metal part to heat up and soften, forming a viscoplastic deformation layer. Then, while the raw material bar is rotating and pressing down, it travels along the length of the metal part at a speed of 100 mm / min to form the cladding layer. During the travel, the rotation speed of the raw material bar remains unchanged (1000 rpm), and the axial feed speed is 33 mm / min. According to the pressure and temperature sensors, the highest temperature of the cooling medium during the cladding process is 42℃, the peak temperature of the metal part surface is 1214℃, and the upsetting pressure is 15kN.

[0081] The surface morphology of the weld overlay obtained in this embodiment is as follows: Figure 3 As shown in Figure (a), from Figure 3 As shown in Figure (a), the surface of the weld overlay is smooth and uniform, with no obvious defects. A cross-section of the weld overlay in this embodiment is observed, as shown... Figure 4As shown in Figure (a), the thickness of the weld overlay is relatively small, and its surface is almost flush with the surface of the metal part, indicating that the viscoplastic deformation layer has approached the surface of the metal part. A clear repair zone is formed inside the metal part, with a maximum repair depth of 1 mm and an effective repair width of 18 mm.

[0082] Comparative Example 1

[0083] Comparative Example 1 uses a 304L bar with a diameter of 20 mm and a length of 150 mm as the raw material bar, and a 304L stainless steel plate with a thickness of 12 mm as the metal part. Friction welding is performed on the surface of the metal part.

[0084] Here, the difference between Comparative Example 1 and Example 1 is that Comparative Example 1 did not apply forced cooling during the friction welding process, but was carried out in an atmospheric environment. That is, Comparative Example 1 omits the step of applying cooling medium, and the other steps and parameters are the same as those in Example 1.

[0085] In Comparative Example 1, due to the absence of forced cooling, the raw material rods softened, deformed, and accumulated at a faster rate, resulting in an uneven, corrugated surface of the accumulated layer (see [reference]). Figure 3 (As shown in Figure (b)). According to sensor measurements, the peak temperature of the metal part surface during the welding process was 1105℃, and the upsetting pressure was 9kN.

[0086] Observation of the cross-section of the weld overlay in this comparative example revealed a relatively large thickness of 2 mm, situated above the metal part. No obvious repair area was formed on the surface of the metal part, indicating ineffective bonding between the weld overlay and the metal part, with a clearly defined interface. Figure 4 As shown in Figure (b).

[0087] Example 2

[0088] In this embodiment, a 304L bar with a diameter of 20 mm and a length of 150 mm is selected as the raw material bar, and a 304L stainless steel plate with a thickness of 12 mm is selected as the metal part. Friction welding is performed on the surface of the metal part. Tap water is used as the cooling medium.

[0089] The difference between this embodiment and Embodiment 1 is that, in the friction surfacing process, the rotational speed of the raw material bar is 1500 rpm, the travel speed is 200 mm / min, and the axial feed speed is 100 mm / min.

[0090] The remaining steps and parameters are the same as in Example 1.

[0091] According to sensor measurements, during the welding process in Example 2, the highest temperature of the cooling medium was 46°C, the peak temperature of the metal part surface was 1280°C, and the upsetting pressure was 18kN. The obtained weld overlay had a good surface formation, and no obvious welding defects were found.

[0092] Comparative Example 2

[0093] Comparative Example 2 uses 304L bars with a diameter of 20 mm and a length of 150 mm as raw material bars and 304L stainless steel plates with a thickness of 12 mm as metal parts. Friction welding is performed on the surface of the metal parts.

[0094] Here, the difference between Comparative Example 2 and Example 2 is that in the friction welding process, the rotation speed of the raw material bar is not matched with the type of medium, and is 400 rpm, which is less than 500 rpm.

[0095] The remaining steps and parameters are the same as in Example 2.

[0096] According to sensor measurements, during the welding process of Comparative Example 2, the peak temperature of the metal part surface was 770℃ and the upsetting pressure was 5kN.

[0097] Comparative Example 2 showed a decrease in the surface smoothness of the weld overlay, with an uneven surface and obvious burrs (see...). Figure 5 (As shown). Due to the low heat input and pressure, sufficient element diffusion and metallurgical bonding were not achieved on the surface of the metal parts, resulting in a distinct interface and the absence of a repair zone.

[0098] Example 3

[0099] In this embodiment, a 304L bar with a diameter of 10 mm and a length of 100 mm is selected as the raw material bar, and a 304L stainless steel plate with a thickness of 10 mm is selected as the metal part. Friction welding is performed on the surface of the metal part. Tap water is used as the cooling medium. The main steps are as follows:

[0100] Assembly and positioning steps: First, fix the metal parts in the steel water tank, and then position and assemble the water tank with the welding machine platform to ensure that the metal parts do not loosen during the repair process.

[0101] Applying cooling medium: Fill the water tank with water through the inlet so that the metal part is completely immersed in the water. When the water level is 30 mm above the surface of the metal part (the depth of the raw material bar immersed in the water during the friction welding process is 3 times the diameter of the raw material bar), open the outlet of the water tank to drain the water, and control the flow rate of the inlet and outlet to be 1 liter / minute.

[0102] Friction cladding process: First, clamp the raw material bar at the end of the welding machine spindle, then rotate it at 1500 rpm and approach the surface of the metal part. After the raw material bar contacts the metal part and generates heat through friction, continue to press down 2 mm (pressing speed is 5 mm / min, and pause for 5 seconds after pressing down), causing the raw material bar and the metal part to heat up and soften, forming a viscoplastic deformation layer. Then, while the raw material bar rotates and presses down, it travels along the length of the metal part at a speed of 30 mm / min to form the cladding layer. During the travel, the rotation speed of the raw material bar remains unchanged (1500 rpm), and the axial feed speed is 10 mm / min. According to the pressure and temperature sensors, the highest temperature of the cooling medium during the cladding process is 43℃, the peak temperature of the metal part surface is 1180℃, and the upsetting pressure is 12kN.

[0103] Upon observation, the surface of the weld overlay obtained in this embodiment is smooth and uniform, with no obvious defects found. Observation of the cross-section of the weld overlay shows that the weld overlay thickness is small, the surface of the weld overlay is almost flush with the surface of the metal part, and a clear repair zone is formed inside the metal part, with a maximum repair depth of 0.5 mm and an effective repair width of 8 mm.

[0104] Comparative Example 3

[0105] Comparative Example 3 uses 304L bars with a diameter of 10 mm and a length of 100 mm as raw materials, and 304L stainless steel plates with a thickness of 10 mm as metal parts. Friction welding is performed on the surface of the metal parts. Tap water is used as the cooling medium.

[0106] The difference between Comparative Example 3 and Example 3 is that, in the step of applying the cooling medium, water is injected into the water tank through the inlet, so that the metal part is completely immersed in the water. When the water level is 10 mm higher than the surface of the metal part (the depth of the raw material rod immersed in the water during the friction welding process is 1 times the diameter of the raw material rod), the outlet of the water tank is opened to drain the water, and the flow rate of both the inlet and outlet is controlled to be 1 liter / minute.

[0107] The remaining steps and parameters are the same as in Example 2.

[0108] In Comparative Example 3, sensor measurements showed that during the friction welding process, the highest temperature of the cooling medium was 60℃, the peak temperature of the metal part surface was 1360℃, and the upsetting pressure was 7kN. Due to insufficient cooling medium capacity and inadequate forced cooling, the raw material bar softened, deformed, and accumulated rapidly, resulting in an uneven, wavy surface. Repair zones formed locally on the metal part surface, and the microstructure of the weld overlay and the repaired areas showed significant growth compared to the original metal part, with the maximum effective repair width being only 3 mm.

[0109] Example 4

[0110] In this embodiment, a 304L bar with a diameter of 20 mm and a length of 150 mm is selected as the raw material bar, and a 304L stainless steel plate with a thickness of 10 mm is selected as the metal part. Friction welding is performed on the surface of the metal part. Liquid nitrogen is used as the cooling medium. The main steps are as follows:

[0111] Assembly and positioning steps: First, fix the metal parts in the steel channel, and then position and assemble the steel channel with the welding machine platform to ensure that the metal parts do not loosen during the repair process.

[0112] Applying cooling medium: Inject liquid nitrogen into the steel tank through a spray gun, so that the raw material bar is immersed in liquid nitrogen and the liquid nitrogen level is 40 mm above the surface of the metal part (the depth of the raw material bar immersed in liquid nitrogen during the friction welding process is twice the diameter of the raw material bar). Then, open the outlet of the cooling pipe and control the flow rate of both the inlet and outlet to be 2 liters / minute.

[0113] Friction cladding process: First, clamp the raw material bar at the end of the welding machine spindle, then rotate it at 2500 rpm and approach the surface of the metal part. After the raw material bar contacts the metal part and generates heat through friction, continue to press down 2 mm (pressing speed is 2 mm / min, and pause for 10 seconds after pressing down), causing the raw material bar and the metal part to heat up and soften, forming a viscoplastic deformation layer. Then, while the raw material bar rotates and presses down, it travels along the length of the metal part at a speed of 50 mm / min to form the cladding layer. During the travel, the rotation speed of the raw material bar remains constant (maintained at 2500 rpm), and the axial feed speed is 20 mm / min. According to the pressure and temperature sensors, during the cladding process, the cooling medium temperature is maintained at -196℃, the peak temperature of the metal part surface is 1050℃, and the upsetting pressure is 15kN.

[0114] Upon observation, the surface of the weld overlay obtained in this embodiment is smooth and uniform, with no obvious defects found. Observation of the cross-section of the weld overlay shows that the weld overlay thickness is small, the surface of the weld overlay is almost flush with the surface of the metal part, and a clear repair zone is formed inside the metal part, with a maximum repair depth of 0.9 mm and an effective repair width of 12 mm.

[0115] Comparative Example 4

[0116] Comparative Example 4 uses a 304L bar with a diameter of 20 mm and a length of 150 mm as the raw material bar, and a 304L stainless steel plate with a thickness of 10 mm as the metal part. Friction welding is performed on the surface of the metal part.

[0117] Here, the difference between Comparative Example 4 and Example 4 is that in the friction welding process, the rotation speed of the raw material bar is not matched with the type of medium, being 1300 rpm, which is less than 1500 rpm.

[0118] The remaining steps and parameters are the same as in Example 4.

[0119] According to sensor measurements, during the welding process of Comparative Example 4, the peak temperature of the metal part surface was 850℃ and the upsetting pressure was 7kN.

[0120] The surface of the weld overlay obtained in Comparative Example 4 was uneven, with reduced flatness and obvious burrs. Due to insufficient heat input and pressure, the metal surface did not achieve sufficient element diffusion and metallurgical bonding, resulting in a clear interface and no repair zone.

[0121] Example 5

[0122] In this embodiment, a 304L bar with a diameter of 10 mm and a length of 100 mm is selected as the raw material bar, and a 304L stainless steel plate with a thickness of 10 mm, a length of 1500 mm, and a width of 1500 mm is selected as the metal part. Friction welding is performed on the part to be repaired. Tap water is selected as the cooling medium, and the cooling medium is applied in a localized cooling manner. The main steps are as follows:

[0123] Assembly and positioning steps: Fix a steel water tank with a length of 500 mm and a width of 500 mm onto the metal part and cover the part to be repaired. Seal the gap between the water tank and the metal part to ensure that the water tank does not leak or loosen during the repair process.

[0124] Applying cooling medium: Fill the water tank with water through the inlet, ensuring the metal part to be repaired is completely submerged. When the water level is 30 mm above the surface of the metal part (the depth to which the raw material rod is submerged in water during friction welding is 3 times the diameter of the raw material rod), open the outlet of the water tank to drain the water, and control the flow rate of both the inlet and outlet to be 1.5 liters / minute.

[0125] Friction cladding process: First, clamp the raw material bar at the end of the welding machine spindle, then rotate it at 800 rpm and approach the surface of the metal part to be repaired. After the raw material bar contacts the metal part and generates heat through friction, continue to press down 2 mm (pressing speed is 2 mm / min, and pause for 3 seconds after pressing down), causing the raw material bar and the metal part to heat up and soften, forming a viscoplastic deformation layer. Then, while rotating and pressing down, the raw material bar travels along the length of the part to be repaired at a speed of 20 mm / min to form the cladding layer. During the travel, the rotation speed of the raw material bar remains unchanged (800 rpm), and the axial feed speed is 20 mm / min. According to the pressure and temperature sensors, the highest temperature of the cooling medium during the cladding process is 38℃, the peak temperature of the metal part surface is 980℃, and the upsetting pressure is 14kN.

[0126] Upon observation, the surface of the weld overlay obtained in this embodiment is smooth and uniform, with no obvious defects found. Observation of the cross-section of the weld overlay reveals that the weld overlay thickness is small, the surface of the weld overlay is almost flush with the surface of the metal part, and a clear repair area is formed inside the metal part, with a maximum repair depth of 0.4 mm and an effective repair width of 7 mm.

[0127] In summary, the embodiments of this invention apply a cooling medium with strong thermal conductivity to the surfaces of the raw material bar and the metal part during friction welding, thereby promptly transferring the heat generated during the welding process. This suppresses excessive temperature rise, softening, and deformation of the raw material bar, increases and stabilizes the upsetting pressure and friction force exerted by the raw material bar on the surface of the metal part, and promotes the metallurgical bonding between the weld layer and the surface of the metal part, thus improving the interfacial bonding strength and surface forming quality of the weld layer. The method of this invention is applicable to the repair of parts with various cooling media, different sizes, and materials, and has the advantages of high repair quality, low cost, and high efficiency. It can promote cost reduction and efficiency improvement in the production process and has broad application prospects.

[0128] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method of frictionally depositing a metal onto a metal part, the method comprising: In the process of friction deposition welding of metal parts with raw material rods, the raw material rods and metal parts are applied with a set type of cooling medium in a set manner, so as to timely conduct the heat generated in the friction deposition welding process, inhibit the excessive softening and deformation of the raw material rods, and improve the top forging pressure and friction force of the raw material rods on the surface of the metal parts; The set type of cooling medium includes any one of water, liquid nitrogen and liquid carbon dioxide; In the process of friction deposition welding, the metal part is completely immersed in the cooling medium or the position to be repaired on the metal part is immersed in the cooling medium; the depth of immersion of the raw material rod in the cooling medium is at least 2 times the maximum cross-sectional dimension of the raw material rod; The friction deposition welding repair method of the metal part comprises the following steps: Assembly positioning step: fixing the metal part in the cooling container or positioning the position to be repaired on the metal part in the cooling container; Cooling medium application step: injecting a set volume of cooling medium into the cooling container; the cooling medium in the cooling container is in a state of continuous flow and update; Friction deposition welding treatment step: clamping the raw material rod at the end of the main shaft of the welding machine, and then performing friction deposition welding treatment on the metal part with the raw material rod; In the friction deposition welding treatment step: The raw material rod is rotated at a first rotation speed and moved towards the surface of the metal part; after the raw material rod and the metal part are in contact and produce heat, the raw material rod is continuously pressed down and rotated for a certain period of time, wherein the pressing down speed is 2-10 mm / min, and the rotation stop time is 0-10 seconds, so that the raw material rod and the metal part are locally heated and softened to form a plastic deformation layer; then, the raw material rod travels along the position to be repaired on the metal part at a set speed while being rotated and pressed down, to form a deposition layer; wherein the rotation speed is controlled to be a second rotation speed, and the pressing down speed is a set axial feed speed during the travel of the raw material rod; after the surface of the position to be repaired is completely covered with the deposition layer, the raw material rod is moved away from the metal part and stopped rotating, to complete the friction deposition welding; In the friction deposition welding treatment step: If the material of the raw material rod and the metal part is stainless steel, and the cooling medium is water, then: the first rotation speed is 500-1500 rpm, the second rotation speed is 500-1500 rpm, the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min; If the material of the raw material rod and the metal part is stainless steel, and the cooling medium is liquid carbon dioxide, then: the first rotation speed is 1000-2000 rpm, the second rotation speed is 1000-2000 rpm, the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min; If the material of the raw material rod and the metal part is stainless steel, and the cooling medium is liquid nitrogen, then: the first rotation speed is 1500-3000 rpm, the second rotation speed is 1500-3000 rpm, the travel speed is 20-200 mm / min, and the axial feed speed is 5-100 mm / min.

2. The frictional build-up welding repair method of a metal piece according to claim 1, characterized by, During the friction deposition process, if the cooling medium is water, the temperature of the cooling medium in the cooling container is controlled to be not higher than 50 DEG C.

3. The frictional build-up welding repair method of metal pieces according to claim 1, characterized in that, The cooling container is provided with a cooling medium inlet and a cooling medium outlet, wherein the cooling medium inlet is connected with a cooling medium conveying pipe and the cooling medium outlet is connected with a cooling medium discharging pipe.

4. The method for frictionally depositing a repair on a metal part according to claim 3, characterized in that, Before the friction deposition process, the cooling medium inlet is opened to inject the cooling medium into the cooling container; when the cooling medium in the cooling container reaches a set volume, the cooling medium outlet is opened to continuously inject and discharge the cooling medium, so that the cooling medium in the cooling container is in a continuously flowing and updating state; then, the friction deposition process is performed.

5. The method for frictionally depositing a repair on a metal part according to claim 4, characterized in that, The injection flow rate of the cooling medium is not less than 1 L / min, and the discharge flow rate of the cooling medium is not less than 1 L / min.

6. The method for frictionally depositing a repair on a metal part according to claim 4, characterized in that, The injection flow rate of the cooling medium is the same as the discharge flow rate of the cooling medium.

7. The method for frictionally depositing a repair weld on a metal part according to any one of claims 1 to 6, characterized in that, The raw material rod is made of the same material as the metal part to be repaired; the raw material rod is used to perform the friction deposition process on the metal part, so that the metal part to be repaired is repaired. The raw material rod is made of the same material as the metal part to be repaired; the raw material rod is used to perform the friction deposition process on the metal part, so that the metal part to be repaired is repaired.

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