A steel piston friction welding device and method

Abstract

The present invention discloses a friction welding device for a steel piston, comprising a skirt tooling and a head tooling. The skirt tooling comprises a first chassis, a spring sleeve, and a top core fixed to the first chassis and coaxially arranged with the spring sleeve, used to position the skirt to be welded so as to adjust the deviation of the skirt to be welded relative to the axis of the first chassis and capable of squeezing the skirt to be welded during welding; the head tooling comprises a second chassis and a center positioning block fixed to the second chassis, used to position the head to be welded so as to adjust the deviation of the head to be welded relative to the axis of the second chassis. The present invention also discloses a method applied to the above-mentioned friction welding device for a steel piston. The above-mentioned friction welding device for a steel piston can reduce the deviation of the piston head and skirt relative to the axis of the welding equipment before welding, and can improve the uniformity and consistency of the force applied to the piston welding surface during welding, thereby effectively solving the technical problems of coaxiality, poor quality of welding flash, and low weld strength in friction welding of steel pistons.

Description

Technical Field

[0001] The present invention relates to the technical field of friction welding, and in particular to a friction welding device for a steel piston. The present invention also relates to a method applied to the friction welding device for a steel piston. Background Art

[0002] As diesel engine burst pressures and specific power continue to increase, the working environment and conditions of pistons are becoming increasingly harsh. Ordinary aluminum pistons, due to their poor wear and high-temperature resistance and large deformation, can no longer meet the requirements of high-performance National VI engines. Currently, welded internal cooling oil channel steel pistons are increasingly favored by OEMs for their high-temperature resistance, high wear resistance, low expansion, and excellent cooling performance. The specific production process involves pre-machining cooling oil channels on the piston head and skirt, then connecting the head and skirt through friction welding to form a closed cooling oil channel to cool the piston. However, in the internal cooling oil channel welding technology currently used at home and abroad, the skirt is mostly clamped with the pin seat surface as the friction welding positioning surface and top forging surface, and the head often relies solely on the chuck for positioning. This will cause the head to be unable to be completely clamped in the center of the tooling due to the different clamping forces of the various chucks on the head during welding, resulting in poor coaxiality of the piston after welding and uneven height and width of the weld burr curling; at the same time, after the skirt is clamped, due to the parallelism of the pin seat surface, the pin seat surface is distributed on both sides of the piston, and the pin hole has been rough-machined during welding, it often causes uneven force in the pre-forging and final forging during welding, which in turn causes poor coaxiality of the piston after welding and poor quality of the weld burr, and may even affect the welding strength, leading to serious consequences.

[0003] Therefore, how to avoid poor coaxiality and welding flash quality and low weld strength of friction welding of steel pistons due to uneven force on the welding surface is a technical problem that technical personnel in this field currently need to solve. Summary of the Invention

[0004] The present invention aims to provide a steel piston friction welding device that can effectively solve technical problems such as poor coaxiality, poor weld flash quality, and low weld strength in friction welding of steel pistons. Another object of the present invention is to provide a steel piston friction welding method applicable to the aforementioned steel piston friction welding device.

[0005] To achieve the above-mentioned objectives, the present invention provides a steel piston friction welding device, comprising a skirt tooling for clamping a skirt workpiece to be welded and a head tooling for clamping a head workpiece to be welded, the skirt tooling comprising a first chassis and a spring sleeve fixed to the first chassis for contacting and abutting against a top forging support shoulder on the skirt workpiece to be welded, the head tooling comprising a second chassis, the skirt tooling further comprising a top core fixed to the first chassis and coaxially arranged with the spring sleeve for positioning the skirt workpiece to be welded so as to adjust the deviation of the skirt workpiece to be welded relative to the axis of the first chassis and capable of squeezing the skirt workpiece to be welded during welding; the head tooling further comprising a center positioning block fixed to the second chassis for positioning the head workpiece to be welded so as to adjust the deviation of the head workpiece to be welded relative to the axis of the second chassis.

[0006] Optionally, the top core includes:

[0007] A contoured positioning block for squeezing the inner cavity surface of the skirt to be welded along the axial direction of the top core during welding;

[0008] A positioning disc connected to the contoured positioning block and connected to the first chassis.

[0009] Optionally, the contoured positioning block includes:

[0010] Two top forging surfaces are arranged at the front end of the profiling positioning block and are used to be set with a preset gap with the inner cavity surface of the skirt part to be welded.

[0011] Optionally, the preset gap ranges from 0.3 to 0.5 mm.

[0012] Optionally, the contoured positioning block further includes:

[0013] Two first positioning surfaces are arranged in one-to-one correspondence with and connected to the top forging surface, and are used to respectively cooperate with the inner side walls of the upper and lower ends of the skirt to be welded;

[0014] Two second positioning surfaces for respectively cooperating with the left and right inner side walls of the skirt to be welded;

[0015] A positioning protrusion is provided between the two top forging surfaces and is used to cooperate with the central through hole of the skirt to be welded.

[0016] Optionally, any of the top forging surfaces and the first positioning surface connected thereto are transitioned through an arc surface.

[0017] Optionally, the spring sleeve is provided with a plurality of first positioning grooves evenly distributed along the circumference of the spring sleeve for cooperating with the rectangular positioning block on the first chassis, and the side of the positioning disc away from the contoured positioning block is provided with a plurality of second positioning grooves corresponding one to one with the first positioning grooves for the rectangular positioning block to be embedded and matched.

[0018] Optionally, a hexagon socket bolt for connecting the top core and the first chassis is provided at the center of the top core.

[0019] Optionally, the top core is further provided with a nitrogen channel for delivering nitrogen to the welding surfaces of the skirt part to be welded and the head part to be welded to prevent oxidation of the welding surfaces.

[0020] The present invention also provides a steel piston friction welding method, comprising:

[0021] Obtaining a head part to be welded and a skirt part to be welded having an upset support shoulder;

[0022] Clamp the head part to be welded by the head tooling, and clamp the skirt part to be welded by the skirt tooling;

[0023] The skirt tooling drives the skirt workpiece to be welded to collide with the head workpiece to be welded so that the skirt workpiece to be welded and the head workpiece to be welded maintain a preset distance;

[0024] The head tooling drives the head workpiece to be welded to rotate;

[0025] The skirt tooling drives the skirt to be welded to be friction welded with the head to be welded under a preset welding pressure;

[0026] A preset upsetting pressure is applied by the skirt tooling for a preset period of time.

[0027] Compared with the above background technology, the present invention designs a steel piston friction welding device for different requirements of friction welding. Specifically, the above-mentioned steel piston friction welding device includes a skirt tooling for clamping the skirt part to be welded and a head tooling for clamping the head part to be welded; wherein, the skirt tooling includes a first chassis and a spring sleeve, the spring sleeve is fixed to the first chassis, the spring sleeve is used to contact and abut with the top forging support shoulder on the skirt part to be welded, and the head tooling includes a second chassis; further, the skirt tooling also includes a top core, and the head tooling also includes a center positioning block, wherein the top core is fixed to the first chassis and is coaxially arranged with the spring sleeve, the top core is used to position the skirt part to be welded to adjust the deviation of the skirt part to be welded relative to the axis of the first chassis and can squeeze the skirt part to be welded during welding; the center positioning block is fixed to the second chassis, and the center positioning block is used to position the head part to be welded to adjust the deviation of the head part to be welded relative to the axis of the second chassis. At the same time, the present invention also provides a steel piston friction welding method, which includes: S1: obtaining a head part to be welded and a skirt part to be welded with a top forging support shoulder; S2: clamping the head part to be welded by the head tooling, and clamping the skirt part to be welded by the skirt tooling; S3: driving the skirt part to be welded to collide with the head part to be welded by the skirt tooling, so that the skirt part to be welded and the head part to be welded maintain a preset distance; S4: driving the head part to be welded to rotate by the head tooling; S5: driving the skirt part to be welded to friction weld with the head part to be welded under a preset welding pressure by the skirt tooling; S6: applying a preset top forging pressure for a preset time by the skirt tooling.

[0028] In this way, the friction welding device for steel pistons is achieved by optimizing the skirt and head fixtures. Specifically, a top core is added to the skirt fixture to position the skirt workpiece to reduce its deviation from the skirt fixture axis and to squeeze the skirt workpiece during welding to improve the uniformity and consistency of force applied to the welding surface of the skirt workpiece during welding. A center positioning block is added to the center of the head fixture to reduce the deviation of the head workpiece from the head fixture axis before welding. This arrangement can effectively solve technical problems such as coaxiality, poor welding flash quality, and low weld strength in friction welding of steel pistons. Furthermore, the friction welding device and method have good application prospects in the field of friction welding of high-performance National VI steel pistons. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figure 1This is a schematic structural diagram of a skirt to be welded with an upset support shoulder disclosed in an embodiment of the present invention;

[0031] Figure 2 This is a schematic structural diagram of a head to be welded disclosed in an embodiment of the present invention;

[0032] Figure 3 This is a schematic structural diagram of a skirt tooling of a steel piston friction welding device disclosed in an embodiment of the present invention;

[0033] Figure 4 This is a schematic structural diagram of a head tooling of a steel piston friction welding device disclosed in an embodiment of the present invention;

[0034] Figure 5 for Figure 3 Schematic diagram of the cross-section structure;

[0035] Figure 6 for Figure 3 Another cross-sectional structural diagram of ;

[0036] Figure 7 for Figure 5 Schematic diagram of the structure of the middle top core;

[0037] Figure 8 for Figure 5 A schematic diagram of the structure of the first chassis;

[0038] Figure 9 for Figure 5 Schematic diagram of the structure of the middle spring sleeve;

[0039] Figure 10 It is a schematic diagram of the structure of the chuck of the head tooling;

[0040] Figure 11 The present invention discloses a flow chart of a friction welding method for a steel piston.

[0041] in:

[0042] 01-skirt to be welded, 011-upsetting support shoulder, 02-head to be welded, 1-skirt tooling, 11-first chassis, 111-rectangular positioning block, 12-spring sleeve, 121-first positioning groove, 13-top core, 131-contoured positioning block, 1311-upsetting surface, 1312-first positioning surface, 1313-second positioning surface, 1314-positioning protrusion, 132-positioning disc, 1321-second positioning groove, 14-hexagon socket bolt, 2-head tooling, 21-second chassis, 22-center positioning block, 23-chuck. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] The core of this invention is to provide a steel piston friction welding device that effectively addresses technical issues such as poor coaxiality, poor weld flash quality, and low weld strength in friction welding of steel pistons. Another core of this invention is to provide a steel piston friction welding method applicable to the aforementioned steel piston friction welding device.

[0045] In order to enable those skilled in the art to better understand the solutions of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0046] It should be noted that the directional terms such as "upper end, lower end, left side, right side" described below are all defined based on the drawings in the specification.

[0047] Please refer to Figures 1 to 11 , Figure 1 This is a schematic structural diagram of a skirt to be welded with an upset support shoulder disclosed in an embodiment of the present invention; Figure 2 This is a schematic structural diagram of a head to be welded disclosed in an embodiment of the present invention; Figure 3 This is a schematic structural diagram of a skirt tooling of a steel piston friction welding device disclosed in an embodiment of the present invention; Figure 4 This is a schematic structural diagram of a head tooling of a steel piston friction welding device disclosed in an embodiment of the present invention; Figure 5 for Figure 3 Schematic diagram of the cross-section structure; Figure 6 for Figure 3 Another cross-sectional structural diagram of ; Figure 7 for Figure 5 Schematic diagram of the structure of the middle top core; Figure 8 for Figure 5 A schematic diagram of the structure of the first chassis; Figure 9 for Figure 5 Schematic diagram of the structure of the middle spring sleeve; Figure 10 It is a schematic diagram of the structure of the chuck of the head tooling; Figure 11 The present invention discloses a flow chart of a friction welding method for a steel piston.

[0048] The steel piston friction welding device provided in an embodiment of the present invention includes a skirt tooling 1 for clamping the skirt part to be welded 01 and a head tooling 2 for clamping the head part to be welded 02; wherein, the skirt tooling 1 includes a first chassis 11 and a spring sleeve 12, the spring sleeve 12 is fixed to the first chassis 11, and the spring sleeve 12 is used to contact and abut against the upset support shoulder 011 on the skirt part to be welded 01, and the head tooling 2 includes a second chassis 21 and a chuck 23.

[0049] In addition, the skirt tooling 1 also includes a top core 13, and the head tooling 2 also includes a center positioning block 22, wherein the top core 13 is fixed to the first chassis 11 and is coaxially arranged with the spring sleeve 12, and the top core 13 is used to position the skirt part to be welded 01 to adjust the deviation of the skirt part to be welded 01 relative to the axis of the first chassis 11 and can squeeze the skirt part to be welded 01 during welding; the center positioning block 22 is fixed to the second chassis 21, and the center positioning block 22 is used to position the head part to be welded 02 to adjust the deviation of the head part to be welded 02 relative to the axis of the second chassis 21.

[0050] In this way, the friction welding device for steel pistons is optimized by: adding a top core 13 to skirt tooling 1 to position skirt workpiece 01 to reduce the deviation of skirt workpiece 01 relative to the axis of skirt tooling 1, and squeezing skirt workpiece 01 during welding to improve the uniformity and consistency of force on the welding surface of skirt workpiece 01; and adding a center positioning block 22 to the center of head tooling 2 to reduce the deviation of head workpiece 02 relative to the axis of head tooling 2 before welding. The above-mentioned arrangement can effectively solve technical problems such as coaxiality, poor welding flash quality, and low weld strength in friction welding of steel pistons, and the above-mentioned friction welding device has good application prospects in the field of friction welding of high-performance National VI steel pistons.

[0051] Of course, according to actual needs, the above-mentioned spring sleeve 12 and top core 13 can be connected to the first chassis 11 by using a positioning block fixed on the first chassis 11. The top core 13 is arranged in the spring sleeve 12, and the assembly gap between the spring sleeve 12 and the top core 13 can be set to 0.3-05mm. The top core 13 is also provided with a bolt located in the center, which is used to connect the top core 13 and the first chassis 11. In this way, the first chassis 11 connected with the spring sleeve 12 and the top core 13 can be connected to the tailstock of the friction welding device by multiple bolts; the center positioning block 22 can also be connected to the second chassis 21 with bolts, and the second chassis 21 is connected to the main shaft of the friction welding device with bolts, and 8 chucks 23 can be provided, and the 8 chucks 23 are fixed to the main shaft along the circumferential direction.

[0052] Furthermore, the top core 13 can be specifically configured to include a contour positioning block 131 and a positioning disc 132, wherein the contour positioning block 131 is used to extrude the inner cavity surface of the skirt to be welded 01 along the axial direction of the top core 13 during welding; the positioning disc 132 is connected to the contour positioning block 131, and the positioning disc 132 is also connected to the first chassis 11.

[0053] Specifically, the profiling positioning block 131 may include two forging surfaces 1311 symmetrically disposed at the front end of the profiling positioning block 131. The forging surfaces 1311 are configured to have a predetermined clearance from the inner surface of the skirt workpiece 01. This clearance can be set within a range of 0.3-0.5 mm. In other words, after the skirt tooling 1 has clamped the skirt workpiece 01, a clearance of 0.3-0.5 mm is provided between the forging surface 1311 at the front end of the top core 13 and the inner surface of the skirt workpiece 01.

[0054] In order to achieve the positioning function of the top core 13, the contoured positioning block 131 can also include two first positioning surfaces 1312, two second positioning surfaces 1313, and a positioning protrusion 1314. Among them, the two first positioning surfaces 1312 are arranged in a one-to-one correspondence with and connected to the top forging surface 1311. The upper and lower first positioning surfaces 1312 respectively cooperate with the upper and lower inner side walls of the skirt part to be welded 01; the left and right second positioning surfaces 1313 respectively cooperate with the left and right inner side walls of the skirt part to be welded 01; the positioning protrusion 1314 is arranged between the two top forging surfaces 1311 and is used to cooperate with the center through hole of the skirt part to be welded 01. Of course, the above-mentioned first positioning surface 1312 can be specifically set as an arc surface, the second positioning surface 1313 can be specifically set as a plane, and the positioning protrusion 1314 can be set as a rectangular block.

[0055] It is understandable that the structure of the above-mentioned contour positioning block 131 is designed according to the structure of the skirt to be welded 01. According to the different structures of the piston skirt, the structure of the contour positioning block 131 can be adjusted accordingly.

[0056] In addition, any top forging surface 1311 and the first positioning surface 1312 connected thereto can be transitioned through an arc surface. Of course, all other corners of the top core 13 can be transitioned through an arc surface.

[0057] On the basis of the above, the spring sleeve 12 is provided with a plurality of first positioning grooves 121 evenly distributed along the circumference of the spring sleeve 12. The first positioning grooves 121 are used to cooperate with the rectangular positioning block 111 on the first chassis 11. In order to achieve the function of the rectangular positioning block 111 to simultaneously position the spring sleeve 12 and the top core 13, the positioning disc 132 of the top core 13 is provided with a plurality of second positioning grooves 1321 on the side away from the contoured positioning block 131. The second positioning grooves 1321 are arranged in a one-to-one correspondence with the first positioning grooves 121. The second positioning grooves 1321 are used for the rectangular positioning block 111 on the first chassis 11 to be embedded and matched, so as to realize the connection between the top core 13, the spring sleeve 12 and the first chassis 11.

[0058] In addition, a hexagon socket bolt 14 for connecting the top core 13 and the first chassis 11 can be provided at the center of the top core 13, that is, a threaded hole that can be matched with the hexagon socket bolt 14 can be provided at the center of the top core 13 and the first chassis 11, so that the top core 13 and the first chassis 11 can be further fastened.

[0059] To optimize the above embodiment, the top core 13 is further provided with a nitrogen channel for delivering nitrogen to the welding surfaces of the skirt and head components to be welded 01 and 02. This nitrogen channel delivers nitrogen into the enclosed cavity formed by the skirt and head components to be welded 01 and 02, preventing oxidation of the welding surfaces of the two components, thereby improving welding efficiency. Of course, corresponding channels communicating with this nitrogen channel are provided on the first chassis 11 and the tailstock of the welding device for connection to a nitrogen pipeline.

[0060] At the same time, the present invention also provides a steel piston friction welding method, which includes:

[0061] S1: Obtain a head welded part 02 and a skirt welded part 01 with an upset support shoulder 011;

[0062] S2: Clamp the head part to be welded 02 by the head tooling 2, and clamp the skirt part to be welded 01 by the skirt tooling 1;

[0063] S3: The skirt tooling 1 drives the skirt workpiece 01 to collide with the head workpiece 02 so that the skirt workpiece 01 and the head workpiece 02 maintain a preset distance;

[0064] S4: The head tooling 2 drives the head welded part 02 to rotate;

[0065] S5: The skirt tooling 1 drives the skirt workpiece 01 to be welded to the head workpiece 02 under a preset welding pressure by friction welding;

[0066] S6: Apply a preset forging pressure for a preset time through the skirt tooling 1.

[0067] It should be noted that in S1, the head part to be welded 02 and the skirt part to be welded 01 are both semi-finished products of piston friction welding, and during the processing of the skirt part to be welded 01, a top forging support shoulder 011 for friction welding is processed at a position 10±0.05mm away from the welding surface.

[0068] The origin of the above-mentioned position of the forging support shoulder 011 is as follows: during welding, the shortening of the skirt to be welded 01 is about 1.25mm + the width of the welding flash is about 5mm + the distance between the lower end face of the forging support shoulder 011 and the flash is at least 3mm (to ensure that the forging support shoulder 011 is outside the welding heat-affected zone, and the flash does not contact the end face of the forging support shoulder 011, so as to prevent the welding flash and the heat-affected zone from cooling too quickly and forming acicular martensite structure). In this way, the forging support shoulder 011 that is conducive to friction welding can be processed, and the width of the forging support shoulder 011 can range from 3-20mm, the thickness can range from 3-15mm, and the roughness range can be ≤Rz10. As a preference, the width of the forging support shoulder 011 can be set to 6mm, the thickness can be set to 5mm, and the roughness can be set to Rz10.

[0069] After the piston welding semi-finished product is processed, the head part to be welded 02 and the skirt part to be welded 01 are respectively loaded into the head tooling 2 and the skirt tooling 1 and clamped. The process of loading the head part to be welded 02 into the tooling and clamping is as follows:

[0070] The welding surface of the head part to be welded 02 faces outward, and the end face is fitted with the second chassis 21 of the head tooling 2. The fitting gap can be set to 0.05-0.1mm. The center hole of the head part to be welded 02 is fitted with the outer wall of the center positioning block 22. The fitting gap can be set to 0.05-0.1mm. After pressing the clamping button, the machine tool spindle of the friction welding device drives the chuck 23 to move inward along the axis of the spindle, and clamps the outer cylindrical surface of the head part to be welded 02 through the chuck 23. The clamping length can be set to 8-15mm.

[0071] The clamping process of the skirt part 01 to be welded into the tooling is as follows:

[0072] The welding surface of the skirt part to be welded 01 faces outward, corresponding to the head part to be welded 02. The outer cylindrical surface of the skirt part to be welded 01 fits with the inner cavity surface of the spring sleeve 12, and the fitting gap can be set to 0.05-0.1mm. The top forging support shoulder 011 fits with the end face of the spring sleeve 12. The gap between the top forging surface 1311 of the top core 13 and the inner cavity surface of the skirt part to be welded 01 can be 0.3-0.5mm. After pressing the clamping button, the tailstock of the friction welding device drives the spring sleeve 12 to move inward. A truncated cone-shaped sleeve is provided on the outside of the spring sleeve 12. Under the clamping action of the truncated cone-shaped sleeve, the inner cavity surface of the spring sleeve 12 can clamp the outer cylindrical surface of the skirt part to be welded 01.

[0073] After clamping is completed, the head part to be welded 02 remains stationary, and the head part to be welded 02 is positioned by the center positioning block 22 to reduce the deviation of the head part to be welded 02 relative to the axis of the second chassis 21. The skirt part to be welded 01 is positioned by the spring sleeve 12 and the top core 13. After clamping, the welding surface runout of the head part to be welded 02 is less than 0.1mm, and the welding surface runout of the skirt is less than 0.1mm; then, the skirt tooling 1 drives the skirt part to be welded 01 and the slide to approach the head part to be welded 02 at a certain speed, and after the two collide, the skirt part to be welded 01 and the head part to be welded 02 maintain a gap of 2.5mm.

[0074] After the above operations are completed, the head tooling 2 and the flywheel are accelerated to the set speed, and then the driving source is disconnected; then, the skirt part to be welded 01 is brought into contact with the head part to be welded 02 under a predetermined welding pressure through the tailstock tooling and friction generates heat (at this time, the end face of the top forging support shoulder 011 of the skirt part to be welded 01 is subjected to force), and the temperature of the welding surface of the head part to be welded 02 and the skirt part to be welded 01 reaches above 1200°C; in this way, under the action of welding temperature and extrusion pressure (the spring sleeve 12 and the top core 13 act at the same time), the total height of the head part to be welded 02 and the skirt part to be welded 01 continues to decrease until the total height of the head part to be welded 02 and the skirt part to be welded 01 is shortened by 2.5mm.

[0075] After the above welding process, the piston coaxiality can reach 0.05. Finally, the flywheel speed is reduced to 0, and the piston height is reduced to within the process requirements. At this time, the predetermined forging pressure is applied again for forging, and this pressure is maintained for a certain period of time (usually 3-10 seconds). The pressure is then reduced to 0, the tooling is loosened, and the piston is removed, and the welding is complete.

[0076] After testing, the total height shortening of the piston is 2.5±0.5mm, the coaxiality of the piston after welding is less than 0.2, the width of the welding heat affected zone is ≤6mm, the strength of the weld zone is ≥ the strength of the non-weld zone, and the weld hardness is ≤400HV.

[0077] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0078] The above describes in detail the friction welding device and method for steel pistons provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above examples is intended only to facilitate understanding of the method and core concepts of the present invention. It should be noted that those skilled in the art will be able to make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications are also within the scope of protection of the claims.

Claims

1. A friction welding device for a steel piston, comprising a skirt tooling (1) for clamping a skirt workpiece (01) to be welded and a head tooling (2) for clamping a head workpiece (02) to be welded, wherein the skirt tooling (1) comprises a first chassis (11) and a spring sleeve (12) fixed to the first chassis (11) and configured to contact and abut against a top forging support shoulder (011) on the skirt workpiece (01), and the head tooling (2) comprises a second chassis (21), characterized in that: The skirt tooling (1) further comprises a top core (13) fixed to the first chassis (11) and coaxially arranged with the spring sleeve (12), used for positioning the skirt part to be welded (01) to adjust the deviation of the skirt part to be welded (01) relative to the axis of the first chassis (11) and capable of squeezing the skirt part to be welded (01) during welding; the head tooling (2) further comprises a center positioning block (22) fixed to the second chassis (21) to position the head part to be welded (02) to adjust the deviation of the head part to be welded (02) relative to the axis of the second chassis (21); The top core (13) comprises: A contoured positioning block (131) for squeezing the inner cavity surface of the skirt to be welded (01) along the axial direction of the top core (13) during welding; A positioning disc (132) connected to the contoured positioning block (131) and connected to the first chassis (11); The contoured positioning block (131) comprises: Two top forging surfaces (1311) provided at the front end of the contoured positioning block (131) and used to be provided with a preset gap with the inner surface of the skirt to be welded (01); The contoured positioning block (131) further comprises: Two first positioning surfaces (1312) arranged in one-to-one correspondence with and connected to the top forging surface (1311) and used to respectively cooperate with the inner side walls of the upper and lower ends of the skirt to be welded (01); Two second positioning surfaces (1313) for respectively cooperating with the left and right inner side walls of the skirt to be welded (01); A positioning protrusion (1314) provided between the two top forging surfaces (1311) and adapted to cooperate with the central through hole of the skirt to be welded (01); The spring sleeve (12) is provided with a plurality of first positioning grooves (121) uniformly distributed along the circumference of the spring sleeve (12) for mating with the rectangular positioning block (111) on the first chassis (11); the positioning disc (132) is provided with a plurality of second positioning grooves (1321) on a side away from the contoured positioning block (131) and corresponding to the first positioning grooves (121) for the rectangular positioning block (111) to be embedded and mated; The top core (13) is also provided with a nitrogen channel for conveying nitrogen to the welding surfaces of the skirt part to be welded (01) and the head part to be welded (02) to prevent oxidation of the welding surfaces.

2. The friction welding device for steel piston according to claim 1, characterized in that: The preset gap ranges from 0.3 to 0.5 mm.

3. The friction welding device for steel piston according to claim 1, characterized in that: Any of the top forging surfaces (1311) and the first positioning surface (1312) connected thereto transitions through an arc surface.

4. The friction welding device for steel piston according to claim 1, characterized in that: A hexagon socket bolt (14) for connecting the top core (13) and the first chassis (11) is provided at the center of the top core (13).

5. A steel piston friction welding method, applied to the steel piston friction welding device according to any one of claims 1 to 4, characterized in that: The steel piston friction welding method comprises: Obtaining a head part to be welded (02) and a skirt part to be welded (01) having an upset support shoulder (011); The head part to be welded (02) is clamped by the head tooling (2), and the skirt part to be welded (01) is clamped by the skirt tooling (1); The skirt part to be welded (01) is driven by the skirt tooling (1) to collide with the head part to be welded (02), so that the skirt part to be welded (01) and the head part to be welded (02) maintain a preset distance; The head workpiece (02) to be welded is driven to rotate by the head tooling (2); The skirt tooling (1) drives the skirt part to be welded (01) to be friction welded with the head part to be welded (02) under a preset welding pressure; A preset forging pressure of a preset duration is applied by the skirt tooling (1).

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