Wear-resistant profile for sofa connectors and process for its production

Abstract

The application relates to the technical field of metal composite material preparation, in particular to an anti-wear profile for a sofa connecting piece and a preparation process thereof, which comprises a profile base body, the profile base body is formed by cold rolling and molding of raw materials with the following mass fractions: iron-based main material, carbon, manganese, chromium, niobium, titanium, zirconium, aluminum, and the rest is inevitable impurities. The application sets the iron-based profile surface strengthening component and integrates an ultrasonic vibration auxiliary device on a roller assembly, utilizes high-frequency mechanical vibration to break the interface oxide film, activates atomic transition, and promotes dislocation multiplication, realizes the technical effects of interface diffusion coefficient promotion, single-pass diffusion layer thickness promotion, rolling pass number reduction, and interface shear strength promotion, significantly reduces the process complexity, and improves the interface bonding strength and production efficiency.

Description

Technical Field

[0001] This invention relates to the field of metal composite material preparation technology, specifically to wear-resistant profiles for sofa connectors and their preparation process. Background Technology

[0002] Sofa connectors are critical load-bearing and moving parts in furniture structures. Their friction functional areas, such as hinge bosses, mounting slots, and limiting steps, need to withstand complex loads including reciprocating friction, insertion and extraction shearing, and periodic impacts. Traditional sofa connector profiles are usually made of a single iron-based alloy, whose surface hardness and wear resistance are insufficient for long-term use. This leads to problems such as wear failure, loosening of slots, and abnormal hinge noises during use, seriously affecting the lifespan of the sofa and the user experience.

[0003] However, the existing technology has the following technical defects:

[0004] Because the contact arc length between the roll and the profile is limited by the ratio of the roll diameter to the profile thickness, the contact time is short, the interfacial diffusion reaction time is insufficient, and the single-pass diffusion layer thickness is small. In order to achieve the required thickness of the transition layer, more cold rolling passes are required, resulting in long production cycles, high energy consumption, and high production costs. In the traditional cold rolling process, the oxide film thickness on the profile surface is 50-100nm. The presence of the oxide film seriously hinders the diffusion of interfacial atoms, resulting in poor continuity of the metallurgical bonding layer between the transition layer and the profile substrate, local delamination defects, and low interfacial shear strength. Under the action of cyclic insertion and extraction loads and impact loads, it is prone to interfacial fatigue cracking failure. In the traditional process, the transition layer fluctuates greatly between batches. When the thickness is less than 100μm, the bonding strength between the wear-resistant layer and the profile substrate drops sharply, resulting in poor product quality consistency.

[0005] Meanwhile, traditional processes require precise control of multiple parameters such as rolling temperature, reduction rate, cooling rate, and rolling speed. Deviations in these parameters can easily lead to uneven transition layer thickness, poor interface bonding, and excessive hardness in the non-friction zone. This results in poor process stability and high skill requirements for operators.

[0006] In summary, it is necessary to propose wear-resistant profiles for sofa connectors and their manufacturing processes to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide wear-resistant profiles for sofa connectors and their manufacturing process, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention proposes a wear-resistant profile for sofa connectors, comprising:

[0010] The profile matrix is ​​formed by melting and cold rolling the following raw materials in parts by weight: 96-98.5 parts iron-based main material, 0.06-0.10 parts carbon, 1.0-1.4 parts manganese, 0.4-0.6 parts chromium, 0.03-0.06 parts niobium, 0.02-0.04 parts titanium, 0.01-0.03 parts zirconium, 0.03-0.07 parts aluminum, with the balance being unavoidable impurities;

[0011] The transition layer is formed in situ on the surface of the friction functional area of ​​the profile substrate by ultrasonic vibration-assisted multi-pass gradient reduction cold rolling large deformation diffusion. It is a metallurgical bonding layer with chromium, manganese and niobium elements continuously increasing in gradient from the profile substrate to the surface. The thickness of the transition layer is 180-220μm, forming a continuous metallurgical bond with the profile substrate without interface. The oxide film thickness at the interface between the transition layer and the profile substrate is ≤20nm.

[0012] The composite layer is deposited onto the surface of the transition layer by online synchronous solid-state deposition during the final cold rolling pass. The composite layer is configured from the inside to the outside as a rolling in-situ fine-grained hardening layer and a nano-ceramic dense layer.

[0013] The friction functional area is a hinged boss, assembly slot and limiting step area formed integrally by multiple cold rolling processes on the profile substrate. The transition layer and composite layer fully cover the outer surface of the friction functional area.

[0014] The rolled in-situ fine-grained hardened layer is formed in-situ by dynamic recrystallization of the profile matrix through the last cold rolling large deformation process, with an average grain size of 0.8-1.5μm, and its raw material composition is consistent with that of the profile matrix.

[0015] The dense nano-ceramic layer is formed by online solid-state deposition of the following raw materials in the final cold rolling pass: 65-70 parts of nano-alumina, 22-27 parts of nano-zirconia, 3-6 parts of nano-titanium oxide, 2-4 parts of silane coupling agent, and 1-2 parts of fluorine-modified polysiloxane.

[0016] This invention also proposes a manufacturing process for wear-resistant profiles used in sofa connectors, comprising the following steps:

[0017] Step 1: Preparation of the base billet. Weigh out 96-98.5 parts of iron-based main material, 0.06-0.10 parts of carbon, 1.0-1.4 parts of manganese, 0.4-0.6 parts of chromium, 0.03-0.06 parts of niobium, 0.02-0.04 parts of titanium, 0.01-0.03 parts of zirconium, and 0.03-0.07 parts of aluminum by mass. Prepare the cold-rolled billet by vacuum melting, continuous casting, and hot rolling. Complete the surface descaling and straightening treatment of the billet.

[0018] Step 2: Ultrasonic vibration system integration. An ultrasonic vibration auxiliary device is integrated into the roll assembly of the rolling mill.

[0019] Step 3: Interface pretreatment, the surface of the cold-rolled billet is pretreated;

[0020] Step 4: Ultrasonic vibration-assisted differentiated cold rolling. Using the cold-rolled billet prepared in Step 1 as the processing base material, in-situ forming of the transition layer and integral forming of the profile cross-section are completed through 5-7 passes of vibration-assisted cold rolling.

[0021] Step 5: Online synchronous composite wear-resistant layer during the final cold rolling pass. Using the vibration-assisted rolling profile completed in Step 4 as a carrier, the composite of the in-situ fine-grained hardened layer and the nano-ceramic dense layer is completed simultaneously at the final cold rolling station.

[0022] Step 6: Online closed-loop straightening and length processing. Through a laser contour detection device and an online stress detection device, the straightness, cross-sectional dimensions, and internal residual stress data of the profile are collected in real time. The control system compares the collected real-time data with preset standards and dynamically adjusts the pressing amount, straightening speed, and straightening force of each roller of the 17-roll straightener to eliminate the internal residual stress and dimensional deviation of the profile. According to the preset length parameters, the servo tracking shearing system completes the length cutting of the profile and completes the collection and packaging of the finished products.

[0023] Preferably, the implementation process of step 2 includes the following steps:

[0024] Step 2.1: Install 2-4 piezoelectric ceramic ultrasonic vibration generators on the outer side of the roll bearing housing. The installation position should be ≥300mm away from the rolling area. The power of each vibration generator should be 1.5-2.5kW.

[0025] Step 2.2: Arrange 4-6 through channels evenly along the circumference inside the roll body. The diameter of each channel is 20-30mm. The inner wall of the channel is machined with a helical rifling structure. The pitch of the helical rifling is 15-20mm and the depth is 0.5-1mm.

[0026] Step 2.3: Insert the reciprocating rod made of titanium alloy into the through channel. The diameter of the reciprocating rod is 18-28mm, and the gap between the reciprocating rod and the channel wall is 0.5-1mm. Fill the gap with high-temperature silicone oil as a damping medium. The working temperature range of the high-temperature silicone oil is -40-200℃, and the viscosity at 40℃ is 50-100 centistokes.

[0027] Step 2.4: Install polytetrafluoroethylene damping blocks at both ends of the through channel for sealing, and install disc spring groups at the ends of the rolls as elastic damping components. The stiffness of the disc spring groups is 800-1200 N / mm, which are used to limit the axial displacement of the rolls within ±2 mm.

[0028] Step 2.5: Configure a cooling system that combines forced air cooling and circulating water cooling to keep the temperature of the vibration generator housing below 60°C.

[0029] Preferably, the implementation process of step 3 includes the following steps:

[0030] Step 3.1: Use 120-grit diamond sandpaper to polish the surface of the profile to remove the oxide scale, so that the surface roughness Ra value is ≤1.6μm;

[0031] Step 3.2: Immerse the sanded profile in an alkaline degreasing agent with a pH of 10-12 for 5-10 minutes to remove surface oil stains;

[0032] Step 3.3: Immerse the degreased profile in a 5%-10% hydrochloric acid solution for 2-3 minutes to remove residual oxides, then wash with water and dry.

[0033] Preferably, the implementation process of step 4 includes the following steps:

[0034] Step 4.1, Cold rolling in the roughing stage: Perform the first and second passes of roughing, with a single pass reduction of 15%-20% and a cumulative total reduction of 30%-35%; the rolling temperature is 900-950℃; the rolling speed is 0.3-0.5m / s; start the ultrasonic vibration generator, set the vibration frequency to 25kHz, the amplitude to 10μm, and the power of each vibration source to 1.8kW;

[0035] Step 4.2, Intermediate rolling stage: Perform the 3rd to 4th intermediate rolling passes, with a single-pass reduction rate of 10%-15% and a cumulative total reduction of 20%-25%; the rolling temperature is 850-900℃; the rolling speed is 0.5-0.8m / s; adjust the ultrasonic vibration parameters, increasing the vibration frequency to 30kHz, the amplitude to 12μm, and the power of each vibration source to 2.0kW; the goal of the intermediate rolling stage is to accumulate the diffusion layer thickness to 120-150μm.

[0036] Step 4.3, Finishing stage cold rolling: Perform finishing rolling for the 5th to 7th passes, with a single pass reduction rate of 5%-8% and a cumulative total reduction of 15%-20%; rolling temperature of 800-850℃; rolling speed of 0.8-1.2m / s; further adjust the ultrasonic vibration parameters, increasing the vibration frequency to 35kHz, the amplitude to 15μm, and the power of each vibration source to 2.3kW; the goal of the finishing stage is to achieve a diffusion layer thickness of 180-220μm.

[0037] Step 4.4, Online Monitoring and Adaptive Control: A laser profile detection device is used to collect profile cross-sectional dimension data in real time; an ultrasonic thickness gauge is used to estimate the diffusion layer thickness in real time. When the detected diffusion layer thickness is less than 180μm, the control system automatically increases the amplitude by 5μm based on the current value, or extends the single-pass rolling time by 10%-15%; when the cumulative diffusion layer thickness of the current 5 passes is less than 150μm, the control system automatically adds the 6th to 7th passes, with each pass supplementing the diffusion layer thickness by 30-40μm.

[0038] Preferably, the implementation process of step 5 includes the following steps:

[0039] Step 5.1: Rolling out the in-situ fine-grained hardened layer:

[0040] The single-pass reduction rate for the friction functional zone is set at 30%-35%;

[0041] The rolling temperature is 750-800℃;

[0042] Dynamic recrystallization is achieved on the transition layer surface of the friction functional zone through large deformation cold rolling, and an in-situ rolled in-situ fine-grained hardened layer with an average grain size of 0.8-1.5μm is formed.

[0043] The hardness data of the hardened layer is collected in real time by an online hardness testing device. When the hardness is lower than 240HB, the control system adjusts the final rolling temperature or reduction rate in the opposite direction to ensure that the hardness of the hardened layer is ≥240HB.

[0044] Step 5.2: Online solid-state deposition of nano-ceramic dense layer:

[0045] Weigh out 65-70 parts by weight of nano alumina, 22-27 parts by weight of nano zirconium oxide, 3-6 parts by weight of nano titanium oxide, and 2-4 parts by weight of silane coupling agent. Mix with anhydrous ethanol and prepare a uniform ceramic slurry by high-speed dispersion and ultrasonic treatment.

[0046] An ultrasonic atomizing spraying station is set at the entrance of the last rolling mill to uniformly deposit ceramic slurry onto the surface of the in-situ fine-grained hardened layer through an ultrasonic atomizing spraying device.

[0047] By utilizing the rolling pressure and residual heat of the last rolling mill, a solid-state sintering bond is achieved between the dense nano-ceramic layer and the in-situ rolled fine-grained hardened layer.

[0048] The coating consists of 1-2 parts by weight of fluorinated modified polysiloxane emulsion, which is then cured online with hot air to complete the sealing process.

[0049] Preferably, in step 4.1, during the rough rolling stage, an online acoustic emission sensor monitors the interface breakage signal in real time. When a signal with a frequency greater than 18kHz and an amplitude greater than 60dB is detected, it is determined to be effective breakage. The goal of the rough rolling stage is to reduce the thickness of the interface oxide film from the initial 50-100nm to 10-20nm, thereby initiating the interface element diffusion process.

[0050] Preferably, the formula for estimating the diffusion layer thickness in step 4.4 is:

[0051] ;

[0052] In the formula, The diffusion layer thickness refers to the thickness of the metallurgical bonding layer formed by the diffusion of alloying elements at the interface between the transition layer and the profile matrix after a single rolling pass, expressed in μm. This is a correction factor, with a value ranging from 1.2 to 1.5. This is the diffusion coefficient, with units of m² / s. The diffusion time refers to the time during which the high temperature is maintained within the contact arc area between the profile and the roll. The current vibration frequency, in kHz. The reference vibration frequency is expressed in kHz. This is the current amplitude, in μm. The reference amplitude is expressed in μm.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention sets up a surface strengthening component for iron-based profiles and integrates an ultrasonic vibration auxiliary device on the roll assembly. It utilizes high-frequency mechanical vibration to break the interface oxide film, activate atomic transitions, and promote dislocation proliferation, thereby achieving the technical effects of increasing the interface diffusion coefficient, increasing the thickness of the diffusion layer per pass, reducing the number of rolling passes, and increasing the interface shear strength. This significantly reduces process complexity and improves interface bonding strength and production efficiency. Detailed Implementation

[0054] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] Example 1: This example provides a method for preparing an ultrasonic vibration-assisted wear-resistant profile for sofa connectors, which is carried out according to the following steps:

[0056] Step 1: Preparation of the matrix blank:

[0057] Weigh out 97 parts by weight of iron-based main material, 0.08 parts of carbon, 1.2 parts of manganese, 0.5 parts of chromium, 0.04 parts of niobium, 0.03 parts of titanium, 0.02 parts of zirconium, and 0.05 parts of aluminum, with the balance being unavoidable impurities. Heat the above raw materials to 1580℃ in a vacuum melting furnace with a vacuum degree of less than 10 Pa, and hold for 30 minutes to ensure complete melting and uniform mixing. Cast the molten metal into billets with a cross-sectional dimension of 150mm x 200mm using continuous casting equipment. After heating the billets to 1150℃ and holding for 2 hours, hot-roll them with a total reduction rate of 80%, resulting in a final hot-rolled plate thickness of 30mm. After surface descaling and straightening, the hot-rolled plate is then subjected to high-pressure water jet to remove surface oxide scale, and finally, a seven-roll straightener is used to eliminate warping deformation to obtain cold-rolled billets.

[0058] Step 2, Ultrasonic Vibration System Integration:

[0059] An ultrasonic vibration auxiliary device is integrated into the roll assembly of the rolling mill. The specific operation is as follows:

[0060] Four piezoelectric ceramic ultrasonic vibration generators are installed 350 mm away from the rolling zone on the outside of the roll bearing housing, using a flange connection. Each vibration generator has a power of 2.0 kW. The piezoelectric ceramic transducers of the vibration generators use PZT-8 type piezoelectric ceramic material, and the operating frequency range is 20-40 kHz.

[0061] Four through channels are evenly arranged circumferentially at 90-degree intervals inside the roll body. Each channel has a diameter of 25mm and a length equal to the length of the roll body. Right-hand helical rifling is machined on the inner wall of the channel using a CNC machining center. The pitch of the helical rifling is 18mm, the depth is 0.8mm, and the helix angle is 15 degrees.

[0062] A 23mm diameter titanium alloy reciprocating rod is inserted into the through-channel, forming a 1mm annular gap between the rod and the channel wall. High-temperature silicone oil (PMX-200 methyl silicone oil) is injected into this gap; its viscosity is 75 centistokes at 40℃, and its operating temperature range is -40℃ to 200℃. The injection volume is 800ml per channel. A 12mm thick PTFE damping block is installed at each end of the through-channel, secured by press-fitting to ensure no leakage of the high-temperature silicone oil.

[0063] One set of disc springs is installed at each end of the roll as an elastic damping component. Each set of disc springs contains 6 disc springs with a single stiffness of 180 N / mm. The combined stiffness is 1000 N / mm through series and parallel connection, which is used to limit the axial displacement of the roll within ±2 mm during vibration.

[0064] The system is equipped with a combination of forced air cooling and circulating water cooling: the forced air cooling uses a centrifugal fan with a flow rate of 500 cubic meters per hour to cool the vibration generator housing; the circulating water cooling system includes a water pump with a flow rate of 50 liters per minute, a cooling water tank with a volume of 200 liters, and a heat exchanger with a heat exchange capacity of 8 kW. The cooling water temperature is 15-25℃, and heat is removed through cooling water channels embedded in the vibration generator housing. The temperature of the vibration generator housing is monitored in real time by a temperature sensor to ensure that the temperature is always below 60℃.

[0065] Step 3, Interface Preprocessing:

[0066] The surface of the cold-rolled billet undergoes pretreatment, and the specific procedures are as follows:

[0067] The cold-rolled billet is fixed on the grinding table, and the surface of the profile is mechanically ground using an angle grinder with 120-grit silicon carbide sandpaper. The grinding direction is reciprocating along the length of the profile, the grinding pressure is 20-30 Newtons, and the grinding speed is 0.5 m / s. After grinding, the surface roughness Ra value is measured with a surface roughness meter to ensure that the Ra value is ≤1.6 μm.

[0068] After polishing, immerse the profile in an alkaline degreasing agent solution at 60℃ and pH 11. The degreasing agent formula is: 30 g / L sodium hydroxide, 20 g / L sodium carbonate, 15 g / L trisodium phosphate, and 10 g / L surfactant. Immerse for 8 minutes. During immersion, gently brush the profile surface with a brush every 2 minutes to promote oil removal. After degreasing, rinse the profile surface with running water for 3 minutes to remove residual alkaline solution.

[0069] After degreasing, the profiles are immersed in an 8% hydrochloric acid solution at 25°C for 2.5 minutes. Immediately after pickling, the profile surface is rinsed with running water for 2 minutes, and then dried with compressed air at a pressure of 0.4 MPa and a temperature of 40°C.

[0070] Step 4: Ultrasonic vibration-assisted differentiated cold rolling:

[0071] Using the cold-rolled billet prepared in step 1 as the processing base material, the in-situ forming of the transition layer and the integral forming of the profile cross-section are completed through 6 passes of vibration-assisted cold rolling. The specific operation is as follows:

[0072] Rough rolling passes 1 to 2:

[0073] Pass 1: Before entering the rolling mill, the profile is heated to 920℃ by an induction heating device with a heating power of 80 kW and a heating time of 120 seconds. An ultrasonic vibration generator is activated, with the vibration frequency set to 25 kHz, amplitude to 10 μm, and power to 1.8 kW per vibration source. The rolling speed is set to 0.4 m / s, and the single-pass reduction rate is 18%, meaning the profile thickness is rolled from 30 mm to 24.6 mm. An online acoustic emission sensor (AE-900 model) monitors the interface breakage signal in real time, with a frequency response range of 10-100 kHz and a sensitivity of 80 dB. Recorded data shows that when the profile passes through the rolling zone, a continuous signal with a frequency of 20-30 kHz and an amplitude of 65-75 dB is detected, indicating effective breakage of the interface oxide film.

[0074] Second pass: The profile is naturally cooled to 880℃ between passes for approximately 30 seconds before re-entering the rolling mill. The rolling speed is set to 0.4 m / s, with a single-pass reduction of 16%, meaning the profile thickness is rolled from 24.6 mm to 20.7 mm. Vibration parameters remain constant: frequency 25 kHz, amplitude 10 μm, and power 1.8 kW per vibration source. After the rough rolling stage, an ultrasonic thickness gauge indicates a diffusion layer thickness of 55-65 μm.

[0075] Third and fourth rolling passes:

[0076] Third pass: The profile is naturally cooled to 870℃ between passes and then enters the rolling mill. Ultrasonic vibration parameters are adjusted: vibration frequency increased to 30kHz, amplitude increased to 12μm, and power increased to 2.0kW per vibration source. The rolling speed is set to 0.6m / s, and the single-pass reduction rate is 12%, meaning the profile thickness is rolled from 20.7mm to 18.2mm.

[0077] Pass 4: The profile is naturally cooled to 830℃ between passes and then enters the rolling mill. Vibration parameters remain constant: frequency 30kHz, amplitude 12μm, and power 2.0kW per vibration source. The rolling speed is set to 0.7m / s, and the single-pass reduction rate is 10%, meaning the profile thickness is rolled from 18.2mm to 16.4mm. After the intermediate rolling stage, ultrasonic thickness gauge readings show a cumulative diffusion layer thickness of 135-145μm.

[0078] Finishing rolling passes 5 to 6:

[0079] Pass 5: The profile is naturally cooled to 820℃ between passes and then enters the rolling mill. The ultrasonic vibration parameters are further adjusted: the vibration frequency is increased to 35kHz, the amplitude to 15μm, and the power to 2.3kW per vibration source. The rolling speed is set to 1.0m / s, and the single-pass reduction rate is 7%, meaning the profile thickness is rolled from 16.4mm to 15.3mm.

[0080] Pass 6: The profile is naturally cooled to 810℃ between passes and then enters the rolling mill. Vibration parameters remain constant: frequency 35kHz, amplitude 15μm, and power 2.3kW per vibration source. The rolling speed is set to 1.1m / s, with a single-pass reduction rate of 6%, meaning the profile thickness is rolled from 15.3mm to 14.4mm. After the finish rolling stage, ultrasonic thickness gauge readings show the final diffusion layer thickness to be 195-205μm.

[0081] Throughout the rolling process, the online monitoring system continuously collects diffusion layer thickness data. Based on the real-time data, the parameter values ​​for the diffusion layer thickness estimation formula are:

[0082] Correction factor k = 1.35; reference diffusion coefficient at 850℃ = 5 * 10 -12 m / s; reference frequency f0 = 25 kHz; reference amplitude A0 = 10 μm;

[0083] After the 5th pass, online monitoring showed that the diffusion layer thickness in a certain local area was 175μm, which was lower than the 180μm threshold. The control system automatically triggered the amplitude compensation program, increasing the amplitude of the 6th pass from 15μm to 18μm, an increase of 3μm. The rolling speed of the 6th pass was also reduced from 1.1m / s to 0.95m / s, extending the rolling time by about 15%. Finally, the diffusion layer thickness in that area reached 192μm, meeting the design requirements.

[0084] Step 5: Final cold rolling online synchronous composite wear-resistant layer:

[0085] Using the 6-pass vibration-assisted rolling profile completed in step 4 as a carrier, the in-situ composite of the fine-grained hardened layer and the nano-ceramic dense layer is simultaneously completed at the 7th cold rolling station. The specific operation is as follows:

[0086] In-situ rolling of fine-grained hardened layer:

[0087] Before the profile enters the final rolling mill, the profile temperature is precisely adjusted to 770℃ using an induction heating device. For the hinge bosses, assembly slots, and limiting steps in the friction functional area, a single-pass reduction rate of 32% is set, meaning the thickness of the friction functional area is rolled from 14.4mm to 9.8mm; for the non-friction functional area, a single-pass reduction rate of 8% is set, meaning the thickness of the non-friction functional area is rolled from 14.4mm to 13.2mm. This differentiated reduction rate achieves the forming of irregular cross-sections in the friction and non-friction functional areas.

[0088] Under the action of a large deformation of 32%, the surface of the transition layer in the friction functional zone undergoes severe plastic deformation, and the grains are significantly elongated and broken. At the same time, at the rolling temperature of 770℃, a dynamic recrystallization process occurs in the deformation zone, and the original coarse grains with a grain size of 10-20μm are transformed into fine grains with an average grain size of 1.2μm, forming a rolling in-situ fine grain hardening layer with a thickness of about 50μm.

[0089] The online hardness testing device uses a portable Leeb hardness tester with a measurement accuracy of ±3HB to perform real-time hardness testing on the surface of the friction functional area.

[0090] The test results show that the hardness needs to meet the design requirement of ≥240HB.

[0091] The hardness test results of the non-friction functional area must meet the design requirement of ≤180HB.

[0092] Online solid-state deposition of nano-ceramic dense layers:

[0093] Weigh out the following proportions by weight: 68 parts of nano-alumina with a particle size of 50 nm and a purity of 99.9%; 25 parts of nano-zirconia with a particle size of 80 nm and a purity of 99.5%; 4 parts of nano-titanium oxide with a particle size of 60 nm and a purity of 99.0%; and 3 parts of silane coupling agent (model KH-550). Mix the above powder raw materials with 300 ml of anhydrous ethanol, place them in a high-speed disperser, disperse at 3000 rpm for 30 minutes, and then transfer them to an ultrasonic cleaner for ultrasonic treatment at a power of 500 watts, a frequency of 40 kHz, and a treatment time of 20 minutes to obtain a uniform and stable ceramic slurry with a solid content of 35%.

[0094] An ultrasonic atomization spraying station is installed 200mm in front of the last rolling mill inlet. The ultrasonic atomization spraying device includes an ultrasonic atomizer with a frequency of 1.65MHz and a power of 100W and six fan-shaped nozzles with a spray angle of 60 degrees and a spray distance of 150mm. When the profile passes through the spraying station, the ceramic slurry is ultrasonically atomized into droplets with an average particle size of 5-10μm. The droplets are sprayed onto the profile surface using compressed air at a pressure of 0.3MPa as a carrier, forming a ceramic slurry wet film with a thickness of approximately 20μm on the surface of the in-situ rolled fine-grained hardened layer.

[0095] The profile, carrying a wet film of ceramic slurry, immediately enters the final rolling mill. Under a rolling pressure of approximately 800 kN, the nanoparticles in the ceramic slurry are compacted, eliminating the porosity between particles. Simultaneously, the profile surface temperature remains at 650-700℃. At this temperature, the ethanol solvent rapidly evaporates, and the silane coupling agent undergoes a hydrolysis-condensation reaction to form a siloxane network structure. The nano-ceramic particles form chemical bonds with the surface of the in-situ fine-grained hardened layer through siloxane bridging bonds, achieving solid-state sintering. The thickness of the dense ceramic layer after rolling is 8-12 μm.

[0096] After leaving the final rolling mill, the profiles are immediately coated with a fluorinated polysiloxane emulsion using a high-pressure airless spraying device at a pressure of 15 MPa. The emulsion has a solid content of 25% and a coating amount of 100 grams per square meter. Immediately after spraying, the profiles enter an online hot air curing device. The hot air temperature is 180℃, the air velocity is 15 m / s, and the curing time is 60 seconds. The fluorinated polysiloxane cross-links and cures at high temperature, forming a tightly sealed layer approximately 3 μm thick on the surface of the nano-ceramic dense layer, further improving the surface's hydrophobicity and corrosion resistance.

[0097] Step 6: Online closed-loop straightening and length-cutting:

[0098] After the final rolling and wear-resistant layer lamination, the profile undergoes full parameter acquisition via an online detection system. A laser profile detection device with a measurement accuracy of 0.02mm, using line laser scanning, acquires the profile's cross-sectional dimensions in real time. The results show that the thickness of the friction functional area is 9.8mm and the thickness of the non-friction functional area is 13.2mm, with dimensional deviations within ±0.05mm. An online stress detection device measures the residual stress within the profile, showing a surface residual stress of 80-120MPa.

[0099] The profiles are straightened using a 17-roll straightener. The straightener employs a closed-loop control system, dynamically adjusting the pressure of each roll based on online monitoring data: the pressure of rolls 1 to 5 gradually increases from 0.1mm to 0.5mm; the pressure of rolls 6 to 12 remains constant at 0.5mm; and the pressure of rolls 13 to 17 gradually decreases from 0.5mm to 0.1mm. The straightening speed is set to 1.5m / s, and the straightening force is automatically adjusted based on the real-time deformation of the profile, with an adjustment range of 150-300kN. After straightening, the straightness of the profile is ≤0.5mm per meter, and the internal residual stress is reduced to 30-50MPa.

[0100] According to preset length parameters, the profile is cut to length using a servo-guided shearing system. The servo-guided shearing system includes a servo motor-driven flying shear device that moves synchronously with the profile, matching the shearing speed to the profile's movement speed, with a shearing accuracy of ±1mm. The cut profiles are then automatically collected and bundled in bundles of 50. The bundles are then double-packaged with moisture-proof paper and plastic film to complete the finished product packaging.

[0101] Example 2, the difference between this example and Example 1 is:

[0102] In step 4, five passes of vibration-assisted cold rolling are used. The specific pass allocation is as follows: two passes in the roughing stage, with single-pass reduction rates of 20% and 18% respectively; two passes in the intermediate rolling stage, with single-pass reduction rates of 14% and 12% respectively; and one pass in the finishing rolling stage, with a single-pass reduction rate of 8%.

[0103] The vibration parameters for each pass were adjusted accordingly: 25kHz vibration frequency and 12μm amplitude for the roughing stage; 32kHz vibration frequency and 14μm amplitude for the intermediate rolling stage; and 38kHz vibration frequency and 15μm amplitude for the finishing rolling stage. This was achieved by increasing the vibration...

[0104] The frequency and amplitude of the vibration compensate for the diffusion time loss caused by the reduction in the number of channels.

[0105] Example 3, the difference between this example and Example 1 is:

[0106] Step 4 employs 7 passes of vibration-assisted cold rolling, specifically allocated as follows: 2 passes in the roughing stage, 3 passes in the intermediate rolling stage, and 2 passes in the finishing stage.

[0107] The vibration parameters for each pass were adjusted accordingly: the vibration frequency was 25 kHz and the amplitude was 8 μm in the roughing stage; the vibration frequency was 28 kHz and the amplitude was 10 μm in the intermediate rolling stage; and the vibration frequency was 32 kHz and the amplitude was 12 μm in the finishing rolling stage. By appropriately reducing the vibration frequency and amplitude, the load on the vibration system was reduced, and the service life of the equipment was extended.

[0108] Example 4, the difference between this example and Example 1 is:

[0109] In step 2, only two ultrasonic vibration generators are installed, with the power of each generator increased to 2.5 kW, and the total power maintained at 5.0 kW.

[0110] The inside of the roll body has only two through channels, the diameter of which is increased to 30mm, and the diameter of the reciprocating rod is correspondingly increased to 28mm.

[0111] Example 5, the difference between this example and Example 1 is:

[0112] The raw material formula of the profile matrix is ​​adjusted to: 96.5 parts iron-based main material, 0.06 parts carbon, 1.0 part manganese, 0.4 parts chromium, 0.03 parts niobium, 0.02 parts titanium, 0.01 parts zirconium, and 0.03 parts aluminum.

[0113] In step 4, the rolling temperature of each pass is increased by 20-30℃: the temperature of the roughing stage is increased to 930-970℃, the temperature of the intermediate rolling stage is increased to 870-920℃, and the temperature of the finishing stage is increased to 820-870℃, in order to compensate for the decrease in diffusion coefficient caused by the reduction in alloy element content.

[0114] Example 6, the difference between this example and Example 1 is:

[0115] The raw material formula of the profile matrix has been adjusted to: 98.5 parts iron-based main material, 0.10 parts carbon, 1.4 parts manganese, 0.6 parts chromium, 0.06 parts niobium, 0.04 parts titanium, 0.03 parts zirconium, and 0.07 parts aluminum.

[0116] In step 4, the rolling temperature of each pass is reduced by 20-30℃: the temperature of the roughing stage is reduced to 880-920℃, the temperature of the intermediate rolling stage is reduced to 820-870℃, and the temperature of the finishing stage is reduced to 770-820℃, so as to avoid excessively high temperatures from causing grain coarsening.

[0117] Example 7, the difference between this example and Example 1 is:

[0118] In step 5, the raw material formula for the dense nano-ceramic layer is adjusted to: 65 parts nano-alumina, 22 parts nano-zirconia, 6 parts nano-titanium oxide, 4 parts silane coupling agent, and 2 parts fluorine-modified polysiloxane.

[0119] Increasing the content of nano-titanium oxide and silane coupling agent further improves the hardness of the ceramic dense layer and the bonding strength with the rolled in-situ fine-grained hardened layer.

[0120] Example 8, the difference between this example and Example 1 is:

[0121] Step 4 simulates the failure of the vibration system: During the third rolling pass, one of the four vibration generators is manually shut down to simulate the failure of a single vibration source and trigger the multi-vibration source redundancy protection mechanism.

[0122] The control system automatically detected a 25% drop in total vibration energy and immediately activated the redundancy protection program: increasing the output power of the remaining three normally operating vibration generators from 2.0 kW to 2.4 kW, bringing the total vibration energy down to 7.2 kW.

[0123] Simultaneously, an amplitude grading compensation mechanism is triggered: at the beginning of the 4th pass, the amplitude is increased from the original 12μm to 15μm, and the rolling time of the 4th pass is extended from the original 8 seconds to 9.2 seconds.

[0124] Example 9, the difference between this example and Example 1 is:

[0125] In step 4, the simulation of insufficient diffusion layer thickness necessitates additional passes: After the 5th pass, the online detection system found that the cumulative diffusion layer thickness was 142 μm, triggering the dynamic adjustment mechanism for the number of passes.

[0126] The control system automatically determined that additional passes were needed, expanding the original 6-pass rolling to 7 passes. The process parameters for the 6th and 7th passes were adjusted as follows: rolling temperature 810℃, rolling speed 1.0m / s, single-pass reduction rate 6%, vibration frequency 35kHz, and amplitude 15μm. The diffusion layer thickness was increased by 35μm and 32μm respectively in the two additional passes.

[0127] Example 10: This example follows the process and parameters of Example 1, applying the wear-resistant profile prepared by this invention to the manufacture of sofa connectors. Specific application areas include the hinge boss, the mounting slot, and the limiting step.

[0128] Comparative Example 1: This comparative example does not use ultrasonic vibration-assisted technology, but uses the traditional cold rolling process to prepare the sofa connector profiles. The specific process parameters are as follows:

[0129] The same raw material formulation and matrix preparation method as in Example 1 were used.

[0130] The conventional 9-pass cold rolling process was adopted without the installation of an ultrasonic vibration generator. The rolling temperature, reduction rate, rolling speed and other parameters were basically the same as those in each pass of Example 1. However, due to the lack of the auxiliary strengthening effect of ultrasonic vibration, the thickness of the diffusion layer in a single pass was only 50-60 μm.

[0131] Comparative Example 2 uses the traditional cold rolling process, but increases the number of rolling passes to 12, which is 3 more than the 9 passes in Comparative Example 1. This is an attempt to increase the thickness of the transition layer by increasing the number of passes. The specific process parameters are as follows:

[0132] The same raw material formulation and matrix preparation method as in Example 1 were used.

[0133] The conventional 12-pass cold rolling process is adopted without the installation of an ultrasonic vibration generator, and the single-pass reduction rate is reduced to 8%-12% to accommodate more passes.

[0134] Comparative Example 3 uses laser surface hardening technology to prepare sofa connector profiles, but does not use the ultrasonic vibration-assisted cold rolling technology of this invention. The specific process parameters are as follows:

[0135] The same raw material formulation and matrix preparation method as in Example 1 were used.

[0136] The profile matrix is ​​prepared using a conventional 6-pass cold rolling process, without the installation of an ultrasonic vibration generator.

[0137] Laser surface hardening treatment is performed on the profile surface: a 3kW fiber laser with a spot diameter of 5mm and a scanning speed of 8mm / s is used to perform laser hardening treatment on the surface of the friction functional area to form a hardened layer with a depth of about 1-2mm.

[0138] Performance testing:

[0139] A1. Transition layer thickness test standard:

[0140] Test standard: GB / T6462-2005 "Microscopic Method for Measuring the Thickness of Metallic and Oxide Coatings";

[0141] Test Method: Samples with dimensions of 20 mm length x 15 mm width x full thickness were cut from the cross-section of the profile using wire cutting to avoid mechanical damage. The samples were then inlaid with epoxy resin and subjected to coarse grinding (180 grit, 320 grit, 600 grit) and fine grinding (1000 grit, 1500 grit, 2000 grit) sequentially using wet sandpaper. Each grinding time was no less than 3 minutes. Finally, the samples were polished for 10 minutes using alumina polishing liquid (0.5 micrometer particle size) on a polishing machine to achieve a mirror finish. Volumetric analysis was then performed. The sample surface was corroded with a 4% nitric acid alcohol solution for 5 to 10 seconds, rinsed with water and dried. The sample was then placed under a metallographic microscope at a magnification of 500x. The thickness of the transition layer was measured using image analysis software along the direction from the interface between the transition layer and the profile substrate to the interface between the transition layer and the composite layer. On the cross-section of the profile, a measurement point was taken every 30 degrees along the circumference, with the center of the friction functional area as the reference, for a total of 12 measurement points. On the longitudinal direction of the profile, a test section was taken every 200 mm, with at least 5 sections tested for each profile.

[0142] Data processing: Calculate the average value, standard deviation, maximum value, and minimum value of all measurement points. The pass / fail criteria are that the average value is within the range of 180 to 220 micrometers and the thickness of all measurement points is greater than or equal to 170 micrometers.

[0143] Judgment criteria:

[0144] Acceptable: Average thickness 180 to 220 micrometers, and single-point thickness greater than or equal to 170 micrometers.

[0145] Non-compliant: Average thickness less than 180 micrometers or greater than 220 micrometers, or a single point with a thickness less than 170 micrometers.

[0146] A2. Interfacial oxide film thickness test standard:

[0147] Test standard: GB / T16594-2008 "General Rules for Measurement Methods of Micrometer-scale Lengths by Scanning Electron Microscopy";

[0148] Test method: Focused ion beam (FIB) technology was used to prepare an ultrathin slice sample with a thickness of approximately 100 nm at the interface between the transition layer and the profile substrate. The ultrathin slice sample was placed on the transmission electron microscope (TEM) stage with an operating voltage of 200 kV and a magnification of 100,000 to 300,000 times. In the TEM bright field image, the oxide film appeared as a gray or dark gray layered structure, which contrasted sharply with the bright white of the metal substrate. The oxide film thickness was measured at 10 random locations in the interface area using the measurement software provided with the TEM, and the average value was taken.

[0149] Judgment criteria: An average oxide film thickness of less than or equal to 20 nanometers is considered qualified, while a thickness greater than 20 nanometers is considered unqualified.

[0150] A3. Interfacial Shear Strength Test Standard:

[0151] Test standard: GB / T6396-2008 "Test Methods for Mechanical Properties of Composite Steel Plates";

[0152] Test method: Prepare shear specimens according to standard requirements. The specimen dimensions are 50 mm in length, 20 mm in width, and thickness, which equals the actual thickness of the profile. The shear surface is located at the interface between the transition layer and the profile substrate. The shear area is 20 mm x 20 mm, which equals 400 square millimeters. Install the specimen in the shear fixture of the universal testing machine, ensuring that the shear surface is parallel to the loading direction. The clamping length is 15 mm. Use displacement control mode and a loading speed of 1 mm per minute. Continuously load until the specimen breaks in shear. The testing machine automatically records the load-displacement curve and records the maximum load value Fmax (in Newtons).

[0153] Number of samples: Five parallel samples were prepared for each group of tests. After removing the maximum and minimum values, the average value of the remaining three samples was taken as the final result.

[0154] Fracture surface observation: After the test, the morphology of the shear fracture surface was observed using a scanning electron microscope (SEM) to determine the fracture mode (interfacial fracture or matrix fracture).

[0155] Judgment criteria:

[0156] Excellent: Shear strength greater than or equal to 160 MPa;

[0157] Acceptable: Shear strength greater than or equal to 150 MPa and less than 160 MPa

[0158] Unacceptable: Shear strength less than 150 MPa

[0159] A4. Surface Hardness Test Standard:

[0160] Test standard: GB / T231.1-2018 "Metallic materials - Brinell hardness test - Part 1: Test method";

[0161] Test method: Clean the surface of the profile to remove oil and oxide scale, and ensure that the test surface is flat and smooth. Use a Brinell hardness tester with a 2.5 mm diameter cemented carbide ball as the indenter.

[0162] Test parameters: test force is 1839 Newtons (corresponding symbol is HB2.5 / 187.5), loading time is 15 seconds, and holding time is 15 seconds.

[0163] Test location:

[0164] Friction functional area: Take 3 test points in each of the friction functional areas such as hinge boss, assembly slot, and limit step, and the distance between each test point is greater than or equal to 4 times the indentation diameter.

[0165] Non-friction functional area: Three test points are randomly selected in the non-friction functional area of ​​the profile.

[0166] Indentation measurement: After loading, the indentation diameters d1 and d2 (diameters in two mutually perpendicular directions) are measured using a reading microscope, and the average value d is equal to (d1 plus d2) divided by 2.

[0167] Hardness calculation: According to the hardness value table in the appendix of GB / T231.1 standard, the Brinell hardness value HB is obtained by looking up the table through the indentation diameter d.

[0168] Data processing: The average value of 3 test points in each area is taken as the hardness value of that area.

[0169] Judgment criteria:

[0170] Friction functional area qualified: hardness greater than or equal to 240HB;

[0171] Non-friction functional area qualification: hardness less than or equal to 180HB;

[0172] Unacceptable: Hardness of friction functional area is less than 240HB or hardness of non-friction functional area is greater than 180HB;

[0173] A5. Abrasion resistance test standard:

[0174] Test standard: GB / T12444.1-2006 "Metallic materials wear test methods - Part 1: Pin test";

[0175] Test method: Cut a square sample with dimensions of 30 mm in length, 30 mm in width, and 5 mm in thickness from the friction functional area of ​​the profile. Grind the surface flat to a roughness Ra of less than or equal to 0.8 micrometers. Use a pin-disc friction and wear tester. The friction pair is a quenched steel ball with a diameter of 6 mm (material GCr15, hardness HRC60 to 63).

[0176] Test parameters:

[0177] Loading force: 50 Newtons;

[0178] Rotational speed: 300 revolutions per minute (corresponding to a linear velocity of approximately 0.094 meters per second);

[0179] Wear time: 60 minutes;

[0180] Test environment: room temperature (20 to 25 degrees Celsius), relative humidity 45% to 55%, dry friction conditions (without lubricant).

[0181] Wear measurement:

[0182] Before the test, the sample was cleaned with acetone and dried, and its mass m1 was weighed using an analytical balance with an accuracy of 0.1 mg.

[0183] After the test, the sample was cleaned with acetone to remove the abrasive and dried, and its mass m2 was weighed again.

[0184] The wear amount Δm is equal to m1 minus m2, and the unit is milligrams.

[0185] Wear rate calculation: Wear rate W equals wear amount Δm divided by applied force F divided by wear time t, with units of milligrams per Newton per hour.

[0186] Wear track observation: After the test, the depth and width of the wear track were measured using a three-dimensional profilometer, and the morphology of the worn surface was observed using a scanning electron microscope to determine the wear mechanism (abrasive wear, adhesive wear, or fatigue wear).

[0187] Judgment criteria:

[0188] Excellent: Wear amount less than or equal to 15 mg, wear rate less than or equal to 0.005 mg / Newton-hour

[0189] Acceptable: Wear amount less than or equal to 20 mg, wear rate less than or equal to 0.007 mg / Newton-hour

[0190] Unacceptable: Wear amount greater than 20 mg, wear rate greater than 0.007 mg / Newton-hour

[0191] A6. Fatigue life test standard:

[0192] Test standard: GB / T3075-2008 "Methods for controlling axial force in fatigue testing of metallic materials";

[0193] Test method:

[0194] Sample preparation: Prepare standard fatigue samples according to standard requirements. The sample type is round bar sample with a gauge length diameter of 6 mm, a gauge length of 30 mm, a transition fillet radius of 10 mm, and a threaded clamping section diameter of 10 mm at both ends.

[0195] Test equipment: An electro-hydraulic servo fatigue testing machine was used, with a frequency range of 0 to 50 Hz and a load accuracy of ±1%.

[0196] Test parameters:

[0197] Loading method: Axial tension-compression symmetrical cyclic loading;

[0198] Loading frequency: 50 Hz;

[0199] Test environment: room temperature (20 to 25 degrees Celsius), relative humidity 45% to 55%, air environment;

[0200] Test termination conditions:

[0201] The specimen completely breaks, or the number of cycles reaches 1 x 10^7 cycles (defined as infinite life).

[0202] Fatigue life record: Record the number of cycles Nf from the start of loading to complete fracture of the specimen, in units of cycles.

[0203] Fracture surface analysis: After the test, the fatigue fracture morphology was observed using a scanning electron microscope to identify the fatigue source, crack propagation zone and instantaneous fracture zone, and to determine the fatigue fracture mode.

[0204] Number of samples: At least 3 parallel samples should be prepared for each group of tests, and the average value should be taken as the final result.

[0205] Judgment criteria:

[0206] Excellent: Fatigue life greater than or equal to 5 x 10^6 cycles;

[0207] Qualified: Fatigue life is greater than or equal to 3 x 10^6 cycles;

[0208] Unacceptable: Fatigue life less than 3 x 10^6 cycles;

[0209] A7. Interface integration continuity test standard:

[0210] Test standard: GB / T13298-2015 "Methods for Examination of Metallic Microstructure";

[0211] Test method: Metallographic specimens were prepared according to the A1 transition layer thickness test standard. The specimens were placed under a metallographic microscope with a magnification of 200 to 500 times, and continuous observation was carried out along the entire interface between the transition layer and the profile substrate.

[0212] Defect identification and statistics:

[0213] Macroscopic layered defects: defined as interfacial cracks or holes with a length greater than or equal to 50 micrometers and a width greater than or equal to 2 micrometers.

[0214] Microscopic discontinuities are defined as interfacial microcracks or micropores with a length of 10 to 50 micrometers and a width of 0.5 to 2 micrometers.

[0215] Continuity rating:

[0216] Observation length: The total length of continuous observation along the interface shall not be less than 10 mm.

[0217] Defect statistics: Record the number of macroscopic stratified defects and the number of microscopic discontinuities within the observation area.

[0218] Continuity calculation: The continuity percentage equals (total observed length minus the sum of all defect lengths) divided by the total observed length multiplied by 100%.

[0219] Judgment criteria:

[0220] Excellent: Continuity greater than or equal to 95%, no macroscopic stratification defects;

[0221] Acceptable: Continuity greater than or equal to 90%, number of macroscopic layering defects less than or equal to 2 per 10 mm;

[0222] Unacceptable: Continuity less than 90%, or more than 2 macroscopic layering defects per 10 mm;

[0223] A8. Dimensional accuracy testing standards:

[0224] Test basis: GB / T4883-2008 "General provisions for acceptance, packaging, marking and quality certificate of structural steel";

[0225] Test method: Using a vernier caliper or micrometer with an accuracy of 0.01 mm, measure every 500 mm along the longitudinal direction of the profile. For each measurement section, measure 3 points (both ends and the center) in the width direction, and measure at least 5 sections for each profile. For irregularly shaped sections such as hinge bosses, assembly slots, and limiting steps, measure their key dimensions (such as boss diameter, slot width, step height, etc.), and measure each part 3 times.

[0226] Data processing: Calculate the average, standard deviation, maximum deviation, and minimum deviation for all measurement points.

[0227] Judgment criteria:

[0228] Acceptable: Dimensional deviation within ±0.1 mm;

[0229] Non-conforming: Dimensional deviation exceeds ±0.1 mm;

[0230] A9. Application Performance Testing Standards:

[0231] A9.1 Reciprocating Friction Fatigue Test of Hinged Boss:

[0232] Test standard: QB / T1952.1-2012 "Upholstered Furniture Sofas"

[0233] Test method: Sample preparation: The profile is processed into a hinge boss structure for practical application, installed in a standard hinge device, and a reciprocating friction fatigue testing machine is used to simulate the hinge movement between the sofa seat and the backrest.

[0234] Test parameters:

[0235] Loading force: 150 Newtons (simulating the force of a human body weight of approximately 75 kg acting on the hinge point);

[0236] Reciprocating frequency: 1 Hz (simulating normal usage frequency);

[0237] Reciprocating angle: 0 to 90 degrees (simulating the adjustment angle of a sofa backrest from upright to tilted);

[0238] Total number of cycles: 100,000 (simulating approximately 10 years of normal use);

[0239] Performance evaluation: The surface wear depth of the hinge boss is checked every 10,000 cycles (measured using a 3D profilometer), and the hinge torque is checked every 10,000 cycles (measured using a torque sensor). After the test, the surface of the hinge boss is checked for cracks, peeling, or other failure phenomena.

[0240] Judgment criteria:

[0241] Excellent: After 100,000 cycles, the wear depth is less than or equal to 0.08 mm, the torque increase is less than or equal to 10%, and there is no failure phenomenon;

[0242] Qualified: After 100,000 cycles, the wear depth is less than or equal to 0.10 mm, the increase in torque is less than or equal to 15%, and there is no failure phenomenon;

[0243] Unacceptable: Wear depth greater than 0.10 mm after 100,000 cycles, or torque increase greater than 15%, or failure phenomenon.

[0244] A9.2 Assembly slot insertion and removal fatigue test:

[0245] Test standard: QB / T1952.1-2012 "Upholstered Furniture Sofas";

[0246] Test method:

[0247] Sample preparation: The profile is processed into an assembly slot structure for practical application, and matched with standard plug-in parts (material is No. 45 steel, surface is galvanized).

[0248] Testing equipment: An electro-hydraulic servo fatigue testing machine equipped with insertion and removal fixtures is used.

[0249] Test parameters:

[0250] Insertion and extraction force: 200 Newtons (simulating the force required for a worker to manually insert and extract an assembly piece).

[0251] Insertion / removal speed: 50 mm / s (simulating normal assembly speed);

[0252] Insertion / removal travel: Approximately 100 mm from full insertion to full removal;

[0253] Total number of plug-in / plug-out cycles: 5000 (simulating the number of plug-in / plug-out cycles during transportation, installation, disassembly, maintenance, etc.);

[0254] Performance evaluation:

[0255] The wear depth of the inner wall of the card slot is measured every 500 insertions and removals (using a three-dimensional profilometer).

[0256] The change in insertion and removal force is detected every 500 insertions and removals (measured using a force sensor).

[0257] After the test, check the card slot for cracks, deformation or other failures.

[0258] Judgment criteria:

[0259] Excellent: After 5000 insertion and extraction cycles, the wear depth is less than or equal to 0.05 mm, the insertion and extraction force attenuation rate is less than or equal to 8%, and there is no failure phenomenon.

[0260] Qualified: After 5000 insertions and removals, the wear depth is less than or equal to 0.08 mm, the insertion and removal force attenuation rate is less than or equal to 12%, and there is no failure phenomenon;

[0261] Unacceptable if: wear depth exceeds 0.08 mm after 5000 insertions and removals, or insertion / removal force attenuation rate exceeds 12%, or failure occurs.

[0262] A9.3 Limiting Step Impact Fatigue Test:

[0263] Test standard: QB / T1952.1-2012 "Upholstered Furniture Sofas";

[0264] Test method:

[0265] Sample preparation: The profile is processed into a limiting step structure for practical application and installed in a standard limiting device.

[0266] Testing equipment: A drop hammer impact tester was used to simulate the limiting impact of the sofa adjustment mechanism.

[0267] Test parameters:

[0268] Impact energy: 15 joules (simulating the impact energy generated by a human body weighing approximately 75 kg falling from a height of approximately 200 mm);

[0269] Impact frequency: 0.5 Hz (simulating the adjustment frequency during normal use);

[0270] Impact method: Vertical impact on the surface of the limiting step

[0271] Total number of impacts: 20,000 (simulating approximately 10 years of normal use);

[0272] Performance evaluation:

[0273] The plastic deformation depth of the limiting step surface is measured every 2000 impacts (using a depth measuring instrument).

[0274] For every 2000 impacts, the surface is inspected for cracks using penetrant testing or magnetic particle testing.

[0275] After the experiment, the microstructure changes on the surface and subsurface of the step were observed using a metallographic microscope.

[0276] Judgment criteria:

[0277] Excellent: After 20,000 impacts, the plastic deformation depth is less than or equal to 0.05 mm, with no cracks and no structural deterioration.

[0278] Acceptable: After 20,000 impacts, the plastic deformation depth is less than or equal to 0.08 mm, with no cracks and slight structural deterioration (deterioration zone depth less than 0.2 mm).

[0279] Unacceptable if: after 20,000 impacts, the depth of plastic deformation is greater than 0.08 mm, or cracks appear, or there is severe structural deterioration.

[0280] A10. Environmental adaptability testing standards:

[0281] A10.1 High Temperature Performance Test:

[0282] Test standard: GB / T2423.2-2008 "Environmental testing of electrical and electronic products - Part 2: Test methods - Test B: High temperature";

[0283] Test method: Prepare three specimens with dimensions of 50 mm in length, 20 mm in width, and thickness equal to the actual thickness of the profile. Place the specimens in a high-temperature test chamber, set the temperature to 80 degrees Celsius, and maintain the temperature for 168 hours (7 days).

[0284] Performance evaluation: After high-temperature exposure, the samples were cooled to room temperature, and the following tests were performed:

[0285] Visual inspection: Check the surface for defects such as oxidation, discoloration, blistering, and cracking.

[0286] Hardness test: Surface hardness was tested according to the A4 standard, and the hardness change before and after high temperature exposure was compared.

[0287] Shear strength test: The interface shear strength was tested according to the A3 standard, and the strength change before and after high temperature exposure was compared.

[0288] Judgment criteria:

[0289] Acceptable: No defects in appearance, hardness variation less than or equal to 5%, shear strength variation less than or equal to 10%.

[0290] Unacceptable if: there are defects in appearance, or the hardness change is greater than 5%, or the shear strength change is greater than 10%.

[0291] A10.2 Low Temperature Performance Test:

[0292] Test standard: GB / T2423.1-2008 "Environmental testing of electrical and electronic products - Part 2: Test methods - Test A: Low temperature";

[0293] Test method: Prepare three specimens with dimensions of 50 mm in length, 20 mm in width, and thickness equal to the actual thickness of the profile. Place the specimens in a low-temperature test chamber with the temperature set to -20 degrees Celsius and the holding time to 168 hours (7 days).

[0294] Performance evaluation: After low-temperature exposure, the samples were heated to room temperature, and the following tests were performed:

[0295] Visual inspection: Check the surface for defects such as cracks and peeling.

[0296] Impact toughness test: Charpy V-notch impact test (GB / T229-2020) was used to test the tendency for low-temperature embrittlement.

[0297] Shear strength test: The interface shear strength was tested according to the A3 standard, and the strength change before and after low temperature exposure was compared.

[0298] Judgment criteria:

[0299] Acceptable: No defects in appearance, impact energy change less than or equal to 15%, shear strength change less than or equal to 10%;

[0300] Unacceptable if: there are defects in appearance, or the impact energy changes by more than 15%, or the shear strength changes by more than 10%;

[0301] A10.3 Damp heat performance test:

[0302] Test standard: GB / T2423.3-2016 "Environmental testing - Part 2: Test methods - Test Cab: Constant damp heat test";

[0303] Test method: Prepare three specimens with dimensions of 50 mm in length, 20 mm in width, and thickness equal to the actual thickness of the profile. Place the specimens in a constant temperature and humidity test chamber with the temperature set at 40 degrees Celsius and the relative humidity set at 90% for 240 hours (10 days).

[0304] Performance evaluation: After exposure to damp heat, the samples were placed under standard atmospheric conditions (temperature 23 degrees Celsius, relative humidity 50%) for 24 hours, and the following tests were performed:

[0305] Visual inspection: Check the surface for defects such as rust, blistering, and peeling.

[0306] Hardness test: Surface hardness was tested according to the A4 standard, and the hardness change before and after humid heat exposure was compared.

[0307] Shear strength test: The interface shear strength was tested according to the A3 standard, and the strength change before and after exposure to damp heat was compared.

[0308] Corrosion resistance evaluation: The corrosion resistance performance was further evaluated by salt spray test (GB / T10125-2012).

[0309] Judgment criteria:

[0310] Acceptable: No obvious rust on the surface (rust area less than 1%), hardness change less than or equal to 5%, and shear strength change less than or equal to 10%;

[0311] Unacceptable: Obvious rust on the surface (rust area greater than or equal to 1%), or hardness change greater than 5%, or shear strength change greater than 10%;

[0312] Record the performance test data, see Tables B1 to B4:

[0313] Table 1: Performance Comparison Test Table of Examples Number of rolling passes path - 6 5 7 6 6 6 6 7 7 6 9 12 6 Less is better Average thickness of transition layer μm A1 198 185 212 190 188 208 198 182 209 198 148 185 - 180 to 220 Standard deviation of transition layer thickness μm A1 4.2 5.8 3.5 6.2 6.8 4.0 4.2 7.5 5.0 4.2 12.5 9.8 - Smaller is better Minimum thickness of transition layer μm A1 192 177 205 181 175 201 192 170 198 192 128 172 - ≥170 Interfacial oxide film thickness nm A2 15 to 18 16 to 20 12 to 16 17 to 21 18 to 22 10 to 14 15 to 18 18 to 24 14 to 18 15 to 18 60 to 85 55 to 80 - ≤20 Interfacial shear strength MPa A3 158 152 165 155 150 167 158 148 161 158 102 108 65 ≥150 Hardness of friction functional area HB A4 252 to 258 245 to 252 255 to 262 248 to 255 242 to 248 258 to 265 256 to 263 243 to 250 253 to 260 252 to 258 235 to 242 238 to 245 420 to 480 (HRC) ≥240 Hardness of non-friction functional area HB A4 165 to 175 168 to 178 162 to 172 166 to 176 170 to 180 160 to 170 165 to 175 167 to 177 163 to 173 165 to 175 172 to 182 168 to 178 165 to 175 ≤180 Abrasion resistance (wear rate) mg A5 18 20 16 19 21 14 15 22 17 18 29 26 35 ≤20 Wear rate mg / N·h A5 0.006 0.007 0.005 0.006 0.007 0.005 0.005 0.007 0.006 0.006 0.010 0.009 0.012 ≤0.007 Fatigue life ×10 6 circulating A6 5.8 5.2 6.5 5.5 5.0 7.2 5.8 4.8 6.0 5.8 3.2 3.8 2.5 ≥3.0 Interface continuity % A7 95 93 97 94 92 98 95 90 96 95 75 82 58 ≥90 Production cycle h - 3.5 3.0 4.0 3.5 3.5 3.5 3.5 4.2 4.2 3.5 5.5 7.0 3.8 Shorter is better Energy consumption kWh / kg - 2.2 2.0 2.4 2.2 2.2 2.2 2.2 2.5 2.4 2.2 3.4 4.2 2.8 The lower the better Production costs Yuan / kg - 18.5 17.8 19.2 18.5 18.2 19.0 18.8 19.5 19.4 18.5 22.0 25.5 24.0 The lower the better Overall evaluation - - excellent qualified excellent qualified qualified excellent excellent qualified excellent excellent Unqualified Qualified but costly Unqualified -

[0314] Please refer to Table 1. Examples 1 to 10 are different combinations of process parameters of the present invention. Comparative Examples 1 to 3 are traditional processes or other technical routes. The hardness of the friction functional area and the hardness of the non-friction functional area are taken as the average value range of the test area. Comparative Example 3 uses laser quenching technology, which has extremely high surface hardness but extremely low interface bonding strength.

[0315] Table 2: Application Performance Test Table

[0316] Please refer to Table 2. The application performance test simulates or tests the actual application conditions of the profile in the sofa connector. Example 10 is an application case of the present invention in an actual sofa product. The data comes from a 2-year follow-up survey. Comparative Example 1 did not fail in the reciprocating friction test of the hinge boss, but the wear depth exceeded the standard. In the assembly slot insertion and removal test, Comparative Example 1 showed slight deformation of the slot after 5000 insertions and removals (the deformation amount was about 0.15 mm).

[0317] Table 3: Environmental Adaptability Test Table High temperature performance test 80℃ 168h Appearance changes - - No oxidation, discoloration, bubbling, or cracking. Slight oxidation and discoloration No defects Example Qualified Hardness change rate % - 2.5 4.8 ≤5 All qualified shear strength change rate % - 5.2 9.5 ≤10 All qualified Low temperature performance test -20℃ 168h Appearance changes - - No cracks or peeling No obvious defects No defects All qualified Rate of change of impact energy % - 8.5 14.2 ≤15 All qualified shear strength change rate % - 6.8 9.2 ≤10 All qualified Damp heat performance test 40℃ / 90%RH 240h Surface rust area % - <0.5 1.2 <1 Example Qualified Hardness change rate % - 3.2 5.8 ≤5 Example Qualified shear strength change rate % - 7.5 11.2 ≤10 Example Qualified Comprehensive environmental adaptability rating - - excellent qualified - The embodiments are superior to the comparative examples.

[0318] Please refer to Table 3. The environmental adaptability test simulates the performance stability of the profile under different climatic conditions. Comparative Example 1 showed slight oxidation and discoloration after the high temperature test, but it did not affect the performance. After the damp heat test, the rust area of ​​Comparative Example 1 was 1.2%, which exceeded the qualified standard (<1%) and was judged as unqualified. Example 1 performed excellently in all environmental adaptability tests.

[0319] Table 4: Vibration System Redundancy Protection Test Table Normal operating conditions No fault No trigger Normal parameters 198μm 158MPa excellent Single vibration source failure Turn off one vibration source (out of a total of four). Multiple vibration source redundancy The power of the remaining three modules has been increased to 120%. 182μm 148MPa qualified Amplitude attenuation The amplitude decreased from 15 μm to 12 μm Amplitude graded compensation Amplitude increased to 15μm 190μm 152MPa qualified Insufficient diffusion layer thickness After the 5th pass, the thickness is only 142μm. The number of times can be dynamically adjusted. Add 6th and 7th courses 209μm 161MPa excellent Multiple faults Two vibration sources failed + amplitude attenuation All redundancy mechanisms triggered The remaining two power levels have been increased to 150%+, with additional stages added. 175μm 145MPa Barely qualified Extreme failure All vibration sources failed Unable to trigger Degenerated into traditional crafts 148μm (9 passes) 102MPa Unqualified

[0320] Please refer to Table 4. The vibration system redundancy protection test verifies the fault tolerance capability and system reliability of the present invention under abnormal working conditions. The single vibration source failure scenario corresponds to the test results of Example 8, the insufficient diffusion layer thickness scenario corresponds to the test results of Example 9, and the multiple failure scenario is an extreme simulation test with an extremely low probability of occurrence in actual production (<0.1%). In the extreme failure scenario, the system automatically switches to the traditional cold rolling mode. Although the number of passes increases to 9, production continuity can still be guaranteed.

[0321] Conclusion Analysis:

[0322] The average number of rolling passes in the examples was 6.2 passes, a reduction of 31.1% compared to the 9 passes in Comparative Example 1. Example 2 showed the best performance, while Examples 3, 8, and 9 had 7 passes. Regarding production cycle time, the examples averaged 3.62 hours, a reduction of 34.2% compared to the 5.5 hours in Comparative Example 1. Examples 1, 2, 4, 5, 6, 7, and 10 all had cycles of 3.0 to 3.5 hours, demonstrating stable and high efficiency. In terms of energy consumption, the examples averaged 2.23 kWh / kg, a reduction of 34.4% compared to the 3.4 kWh / kg in Comparative Example 1, with Example 2 showing the best performance. Regarding production cost, the examples averaged 18.74 yuan / kg, a reduction of 14.8% compared to the 22.0 yuan / kg in Comparative Example 1, with Example 2 showing the best performance. Comparative Examples 2 and 3, due to complex processes or expensive equipment, had costs as high as 24.0 to 25.5 yuan / kg. Example 1 achieves the best balance between process efficiency and economy with 6 passes, 3.5 hours, 2.2 kWh / kg, and 18.5 yuan / kg. The cost is only 3.9% higher than the optimal solution in Example 2, but the performance indicators are significantly better than those in Example 2.

[0323] Transition layer quality analysis: The average transition layer thickness of the examples is 196.8 micrometers, a 33.0% improvement compared to 148 micrometers in Comparative Example 1. Examples 1, 7, and 10, with a thickness of 198 micrometers, are in the middle of the design range, providing sufficient safety margin. Regarding thickness uniformity, the average standard deviation of the examples is 5.14 micrometers, a 69% improvement compared to 12.5 micrometers in Comparative Example 1. Examples 1, 7, and 10 have a standard deviation of 4.2 micrometers, representing the optimal uniformity level. In terms of minimum thickness, the examples average 188.3 micrometers, exceeding the critical value of 170 micrometers by 10.8%. Examples 1, 7, and 10 have a minimum thickness of 192 micrometers, providing a safety margin of 12.9%, while Comparative Example 1 has a minimum thickness of 128 micrometers, below the critical value by 24.7%, posing a risk of failure. Although Example 3 has the highest thickness and best uniformity, the number of passes increases to 7, extending the production cycle to 4.0 hours. Example 6 reaches a thickness of 208 micrometers, but raw material costs increase by approximately 5%. Examples 2, 5, and 8 have thicknesses close to the lower limit, resulting in smaller safety margins. Example 1 achieves optimal stability and reliability of transition layer quality with an average thickness of 198 micrometers, a standard deviation of 4.2 micrometers, and a minimum thickness of 192 micrometers.

[0324] Interface bonding performance analysis: The average interface oxide film thickness of the examples was 15.5 nm, which is 75% to 82% lower than that of Comparative Example 1 (60 to 85 nm). The oxide film thickness of Examples 1, 7, and 10 was 15 to 18 nm, which is at an excellent level. Regarding shear strength, the examples averaged 157.2 MPa, which is 54.1% higher than that of Comparative Example 1 (102 MPa). The shear strength of Examples 1, 7, and 10 was 158 MPa, exceeding the design lower limit by 5.3%. In contrast, the laser-quenched shear strength of Comparative Example 3 was only 65 MPa, which is 56.7% lower than the design lower limit. Regarding interface continuity, the examples averaged 94.5%, which is 26.0% higher than that of Comparative Example 1 (75%). The interface continuity of Examples 1, 7, and 10 was 95%, which is at an excellent level. The interface continuity of Comparative Example 3 was 58%, far below the design lower limit, indicating a serious risk of delamination. Although Example 6 achieved the thinnest oxide film, highest shear strength, and best interfacial continuity, it increased raw material costs. Example 8, with an oxide film thickness of 18 to 24 nanometers and a shear strength of 148 MPa, was close to the design lower limit but still met the requirements. Example 1, with an oxide film of 15 to 18 nanometers, a shear strength of 158 MPa, and 95% interfacial continuity, achieved stable compliance with interfacial bonding quality standards.

[0325] Surface performance analysis: The average hardness of the friction functional area in the examples was 250.4 HB, exceeding the design lower limit by 4.3%. The hardness of Example 1 was 252 to 258 HB, exceeding the design lower limit by 5.0% to 7.5%. The hardness of Comparative Example 1 was 235 to 242 HB, which did not meet the standard. Although the hardness of Comparative Example 3, which was laser-quenched to 420 to 480 HB, was extremely high, poor interfacial bonding led to failure. Regarding wear resistance, the average wear amount in the examples was 18.0 mg, a 38.0% reduction compared to 29 mg in Comparative Example 1. The wear amount in Example 1 was 18 mg, meeting the design requirements with a 10% margin. The wear amount in Example 7 was 15 mg, and in Example 6 it was 14 mg. Regarding fatigue life, the average fatigue life of the examples was 5.76 × 10⁻⁶. 6 The cycle, compared to 3.2 × 10 in Comparative Example 1. 6 Improved by 80.0%, fatigue life in Example 1 was 5.8 × 10⁻⁶. 6 Cycles exceeded the design lower limit by 93.3%, Example 6 fatigue life 7.2 × 10⁻⁶. 6 Cycles exceeded the design lower limit by 140%, and the fatigue life of Comparative Example 3 was 2.5 × 10⁻⁶. 6 Cyclic, below the design lower limit. Example 1 with a hardness of 252 to 258 HB, 18 mg wear amount, 5.8 × 10⁻⁶ 6 Cyclic fatigue life is achieved, ensuring that all surface properties meet the required standards.

[0326] Process stability analysis: Examples 1, 7, and 10 used the same process parameters, and the data were highly consistent, fully demonstrating excellent process repeatability and minimal batch-to-batch fluctuations. Regarding fault tolerance under abnormal operating conditions, Example 8 simulated a single vibration source failure condition; although performance decreased, all indicators still reached the design lower limit, verifying the effectiveness of the multi-vibration source redundancy protection mechanism. Example 9 simulated an automatic compensation condition for insufficient thickness; by triggering a dynamic adjustment mechanism for the number of passes, the 6th and 7th passes were added, ultimately achieving a thickness of 209 micrometers, verifying the adaptive adjustment capability. Regarding process parameter adaptability, Example 2 achieved the target even with reduced pass counts; Example 3 showed a significant performance improvement with increased pass counts; Example 5 achieved the target even with reduced raw material costs; and Example 6 showed a substantial performance improvement with increased raw material costs, fully demonstrating strong process flexibility. Example 1 used standard process parameters, with sufficient repeatability verification and optimal stability.

[0327] In summary, based on performance testing and analysis, Example 1 is the preferred embodiment of the present invention.

[0328] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. Abrasion-resistant profile for sofa connectors, characterized in that, include: The profile matrix is ​​formed by melting and cold rolling the following raw materials in parts by weight: 96-98.5 parts iron-based main material, 0.06-0.10 parts carbon, 1.0-1.4 parts manganese, 0.4-0.6 parts chromium, 0.03-0.06 parts niobium, 0.02-0.04 parts titanium, 0.01-0.03 parts zirconium, 0.03-0.07 parts aluminum, with the balance being unavoidable impurities; The transition layer is formed in situ on the surface of the friction functional area of ​​the profile substrate by ultrasonic vibration-assisted multi-pass gradient reduction cold rolling large deformation diffusion. It is a metallurgical bonding layer with chromium, manganese and niobium elements continuously increasing in gradient from the profile substrate to the surface. The thickness of the transition layer is 180-220μm, forming a continuous metallurgical bond with the profile substrate without interface. The oxide film thickness at the interface between the transition layer and the profile substrate is ≤20nm. The composite layer is deposited onto the surface of the transition layer by online synchronous solid-state deposition during the final cold rolling pass. The composite layer is configured from the inside to the outside as a rolling in-situ fine-grained hardening layer and a nano-ceramic dense layer. The friction functional area is a hinged boss, assembly slot and limiting step area formed integrally by multiple cold rolling processes on the profile substrate. The transition layer and composite layer fully cover the outer surface of the friction functional area. The rolled in-situ fine-grained hardened layer is formed in-situ by dynamic recrystallization of the profile matrix through the last cold rolling large deformation process, with an average grain size of 0.8-1.5μm, and its raw material composition is consistent with that of the profile matrix. The dense nano-ceramic layer is formed by online solid-state deposition of the following raw materials in the final cold rolling pass: 65-70 parts of nano-alumina, 22-27 parts of nano-zirconia, 3-6 parts of nano-titanium oxide, 2-4 parts of silane coupling agent, and 1-2 parts of fluorine-modified polysiloxane.

2. The manufacturing process of the wear-resistant profile for sofa connectors as described in claim 1, characterized in that, Includes the following steps: Step 1: Preparation of the base billet. Weigh out 96-98.5 parts of iron-based main material, 0.06-0.10 parts of carbon, 1.0-1.4 parts of manganese, 0.4-0.6 parts of chromium, 0.03-0.06 parts of niobium, 0.02-0.04 parts of titanium, 0.01-0.03 parts of zirconium, and 0.03-0.07 parts of aluminum by mass. Prepare the cold-rolled billet by vacuum melting, continuous casting, and hot rolling. Complete the surface descaling and straightening treatment of the billet. Step 2: Ultrasonic vibration system integration. An ultrasonic vibration auxiliary device is integrated into the roll assembly of the rolling mill. Step 3: Interface pretreatment, the surface of the cold-rolled billet is pretreated; Step 4: Ultrasonic vibration-assisted differentiated cold rolling. Using the cold-rolled billet prepared in Step 1 as the processing base material, in-situ forming of the transition layer and integral forming of the profile cross-section are completed through 5-7 passes of vibration-assisted cold rolling. Step 5: Online synchronous composite wear-resistant layer during the final cold rolling pass. Using the vibration-assisted rolling profile completed in Step 4 as a carrier, the composite of the in-situ fine-grained hardened layer and the nano-ceramic dense layer is completed simultaneously at the final cold rolling station. Step 6: Online closed-loop straightening and length processing. Through a laser contour detection device and an online stress detection device, the straightness, cross-sectional dimensions, and internal residual stress data of the profile are collected in real time. The control system compares the collected real-time data with preset standards and dynamically adjusts the pressing amount, straightening speed, and straightening force of each roller of the 17-roll straightener to eliminate the internal residual stress and dimensional deviation of the profile. According to the preset length parameters, the servo tracking shearing system completes the length cutting of the profile and completes the collection and packaging of the finished products.

3. The manufacturing process of the wear-resistant profile for sofa connectors according to claim 2, characterized in that, The implementation process of step 2 includes the following steps: Step 2.1: Install 2-4 piezoelectric ceramic ultrasonic vibration generators on the outer side of the roll bearing housing. The installation position should be ≥300mm away from the rolling area. The power of each vibration generator should be 1.5-2.5kW. Step 2.2: Arrange 4-6 through channels evenly along the circumference inside the roll body. The diameter of each channel is 20-30mm. The inner wall of the channel is machined with a helical rifling structure. The pitch of the helical rifling is 15-20mm and the depth is 0.5-1mm. Step 2.3: Insert the reciprocating rod made of titanium alloy into the through channel. The diameter of the reciprocating rod is 18-28mm, and the gap between the reciprocating rod and the channel wall is 0.5-1mm. Fill the gap with high-temperature silicone oil as a damping medium. The working temperature range of the high-temperature silicone oil is -40-200℃, and the viscosity at 40℃ is 50-100 centistokes. Step 2.4: Install polytetrafluoroethylene damping blocks at both ends of the through channel for sealing, and install disc spring groups at the ends of the rolls as elastic damping components. The stiffness of the disc spring groups is 800-1200 N / mm, which are used to limit the axial displacement of the rolls within ±2 mm. Step 2.5: Configure a cooling system that combines forced air cooling and circulating water cooling to keep the temperature of the vibration generator housing below 60°C.

4. The manufacturing process of the wear-resistant profile for sofa connectors according to claim 3, characterized in that, The implementation process of step 3 includes the following steps: Step 3.1: Use 120-grit diamond sandpaper to polish the surface of the profile to remove the oxide scale, so that the surface roughness Ra value is ≤1.6μm; Step 3.2: Immerse the sanded profile in an alkaline degreasing agent with a pH of 10-12 for 5-10 minutes to remove surface oil stains; Step 3.3: Immerse the degreased profile in a 5%-10% hydrochloric acid solution for 2-3 minutes to remove residual oxides, then wash with water and dry.

5. The manufacturing process of the wear-resistant profile for sofa connectors according to claim 4, characterized in that, The implementation process of step 4 includes the following steps: Step 4.1, Cold rolling in the roughing stage: Perform the first and second passes of roughing, with a single pass reduction of 15%-20% and a cumulative total reduction of 30%-35%; the rolling temperature is 900-950℃; the rolling speed is 0.3-0.5m / s; start the ultrasonic vibration generator, set the vibration frequency to 25kHz, the amplitude to 10μm, and the power of each vibration source to 1.8kW; Step 4.2, Intermediate rolling stage: Perform the 3rd to 4th intermediate rolling passes, with a single-pass reduction rate of 10%-15% and a cumulative total reduction of 20%-25%; the rolling temperature is 850-900℃; the rolling speed is 0.5-0.8m / s; adjust the ultrasonic vibration parameters, increasing the vibration frequency to 30kHz, the amplitude to 12μm, and the power of each vibration source to 2.0kW; the goal of the intermediate rolling stage is to accumulate the diffusion layer thickness to 120-150μm. Step 4.3, Finishing stage cold rolling: Perform finishing rolling for the 5th to 7th passes, with a single pass reduction rate of 5%-8% and a cumulative total reduction of 15%-20%; rolling temperature of 800-850℃; rolling speed of 0.8-1.2m / s; further adjust the ultrasonic vibration parameters, increasing the vibration frequency to 35kHz, the amplitude to 15μm, and the power of each vibration source to 2.3kW; the goal of the finishing stage is to achieve a diffusion layer thickness of 180-220μm. Step 4.4, Online Monitoring and Adaptive Control: A laser profile detection device is used to collect profile cross-sectional dimension data in real time; an ultrasonic thickness gauge is used to estimate the diffusion layer thickness in real time. When the detected diffusion layer thickness is less than 180μm, the control system automatically increases the amplitude by 5μm based on the current value, or extends the single-pass rolling time by 10%-15%; when the cumulative diffusion layer thickness of the current 5 passes is less than 150μm, the control system automatically adds the 6th to 7th passes, with each pass supplementing the diffusion layer thickness by 30-40μm.

6. The manufacturing process of the wear-resistant profile for sofa connectors according to claim 5, characterized in that, The implementation process of step 5 includes the following steps: Step 5.1: Rolling out the in-situ fine-grained hardened layer: The single-pass reduction rate for the friction functional zone is set at 30%-35%; The rolling temperature is 750-800℃; Dynamic recrystallization is achieved on the transition layer surface of the friction functional zone through large deformation cold rolling, and an in-situ rolled in-situ fine-grained hardened layer with an average grain size of 0.8-1.5μm is formed. The hardness data of the hardened layer is collected in real time by an online hardness testing device. When the hardness is lower than 240HB, the control system adjusts the final rolling temperature or reduction rate in the opposite direction to ensure that the hardness of the hardened layer is ≥240HB. Step 5.2: Online solid-state deposition of nano-ceramic dense layer: Weigh out 65-70 parts by weight of nano alumina, 22-27 parts by weight of nano zirconium oxide, 3-6 parts by weight of nano titanium oxide, and 2-4 parts by weight of silane coupling agent. Mix with anhydrous ethanol and prepare a uniform ceramic slurry by high-speed dispersion and ultrasonic treatment. An ultrasonic atomizing spraying station is set at the entrance of the last rolling mill to uniformly deposit ceramic slurry onto the surface of the in-situ fine-grained hardened layer through an ultrasonic atomizing spraying device. By utilizing the rolling pressure and residual heat of the last rolling mill, a solid-state sintering bond is achieved between the dense nano-ceramic layer and the in-situ rolled fine-grained hardened layer. The coating consists of 1-2 parts by weight of fluorinated modified polysiloxane emulsion, which is then cured online with hot air to complete the sealing process.

7. The manufacturing process of the wear-resistant profile for sofa connectors according to claim 6, characterized in that, In step 4.1, during the rough rolling stage, the online acoustic emission sensor monitors the interface breakage signal in real time. When a signal with a frequency greater than 18kHz and an amplitude greater than 60dB is detected, it is determined to be effective breakage. The goal of the rough rolling stage is to reduce the thickness of the interface oxide film from the initial 50-100nm to 10-20nm and initiate the interface element diffusion process.

8. The manufacturing process of the wear-resistant profile for sofa connectors according to claim 7, characterized in that, The estimation formula for estimating the diffusion layer thickness in step 4.4 is as follows: ； In the formula, The diffusion layer thickness refers to the thickness of the metallurgical bonding layer formed by the diffusion of alloying elements at the interface between the transition layer and the profile matrix after a single rolling pass, expressed in μm. This is a correction factor, with a value ranging from 1.2 to 1.

5. This is the diffusion coefficient, with units of m² / s. The diffusion time refers to the time the high temperature is maintained within the contact arc area between the profile and the roll. The current vibration frequency, in kHz. The reference vibration frequency is expressed in kHz. This is the current amplitude, in μm. The reference amplitude is expressed in μm.

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