Manufacturing process of ultra-strong wear-resistant tire protection chain

Abstract

The invention relates to the technical field of metal material manufacturing, and discloses a manufacturing process of a super-strong wear-resistant tire protection chain, which comprises the following steps of: forming a chain link blank by adopting high-silicon high-manganese bainite steel through hot rolling and hot die forging; the core of the method is an integrated heat treatment step, specifically, surface functionalization co-permeation of copper and cerium elements is synchronously carried out in the austenitizing stage, then bainite isothermal quenching is carried out, and a composite structure of bainite and stable retained austenite is obtained in a matrix; the process further comprises the steps that a special high-toughness welding wire is adopted for welding, and local tempering treatment is conducted on a welding seam; by means of the scheme, the chain link is endowed with excellent obdurability and fatigue resistance through the phase transformation induced plasticity effect of the base body, the abrasion resistance is remarkably improved through the surface functionalization co-cementation layer, and the reliability of a joint area is ensured through accurate welding and postweld treatment. The technical problems that wear resistance and toughness of a traditional protection chain are difficult to consider at the same time, and a welding joint is prone to failure are systematically solved.

Description

Technical Field

[0001] This invention relates to the field of metal material manufacturing technology, specifically to a manufacturing process for an ultra-strong wear-resistant tire protection chain. Background Technology

[0002] Tire protection chains are critical protective components for engineering vehicle tires, widely used in harsh working conditions such as mines, tunnels, and quarries. To meet their stringent requirements for high strength, high wear resistance, and high fatigue resistance, current technologies typically use medium-to-high carbon alloy steel as raw material, forming the chain links through hot working processes such as forging and rolling, and finally assembling them through welding. Technological development in this field has long focused on optimizing alloy composition, improving forming processes, and enhancing welding quality to extend the service life of the protection chains.

[0003] However, existing manufacturing processes still present inherent technical contradictions in achieving a balance of overall performance. To obtain excellent wear resistance, chain links typically require quenching to obtain a high-hardness martensitic structure, but this often comes at the cost of toughness, increasing the risk of brittle fracture during use. Furthermore, traditional processes assemble chain links into a mesh before performing overall "bundled" quenching. This method results in severely uneven cooling rates between the inside and outside of the mesh, causing inconsistencies in product hardness and microstructure. Internal chain links tend to have lower hardness and wear prematurely, while external chain links may become brittle due to overcooling, significantly impacting the overall service life of the protective chain.

[0004] More importantly, the welded joint is an inherently weak link in the entire protective chain structure. Traditional welding and heat treatment processes struggle to achieve a proper match between the weld area and the base material's properties. The high-temperature thermal cycling during welding destroys the excellent microstructure of the base material obtained through pre-heat treatment, resulting in coarse, poorly ductile microstructures in the weld and heat-affected zone, making them stress concentration points and sources of cracks. While existing technologies aim to improve the quality of the weld itself, they fail to address the performance degradation problem in the welded joint area from a systematic perspective encompassing material design, overall heat treatment, and welding processes.

[0005] Therefore, this invention proposes a manufacturing process for an ultra-strong wear-resistant tire protection chain to overcome the shortcomings of existing technologies. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a manufacturing process for an ultra-wear-resistant tire protection chain, which solves the problem of the difficulty in synergistically improving the wear resistance, core toughness, and weld joint reliability of the tire protection chain.

[0007] To achieve the above objectives, the present invention provides a manufacturing process for an ultra-strong wear-resistant tire protection chain, employing the following technical solution:

[0008] A manufacturing process for an ultra-strong wear-resistant tire protection chain includes the following steps: S1, melting raw materials containing the following mass percentages and forming them into chain link blanks: C: 0.35%–0.50%, Si: 1.0%–3.0%, Mn: 1.5%–3.5%, Cr: 0.5%–1.5%, Mo: 0.10%–0.30%, with the balance being Fe and unavoidable impurities; S2, heating the chain link blanks at 850–950°C. Austenitizing treatment, held at temperature for 50–100 minutes, followed by surface functionalization co-diffusion treatment at the austenitizing temperature, held for 100–300 minutes, and then isothermal quenching at 300–400℃ for 60–240 minutes; S3, assemble the heat-treated chain links and weld the openings closed; S4, perform local tempering treatment on the weld and heat-affected zone at 400–500℃ for 60–180 seconds.

[0009] By adopting the above technical solutions, this invention systematically integrates material design, heat treatment processes, and welding technology to achieve superior comprehensive performance. Its core innovative principle lies in: the design of the bainitic steel matrix material: the composition system in step S1, especially the high silicon content (1.0%–3.0%), is specifically designed to obtain a carbide-free bainitic structure. During the isothermal quenching of bainite in step S2, the high silicon content effectively inhibits the precipitation of brittle carbides during the bainitic transformation, promoting the formation of a structure with excellent toughness and strength, consisting of bainitic ferrite laths and a carbon-rich residual austenite film. Integration of heat treatment and surface modification: step S2 completes the surface functionalization co-diffusion treatment and austenitization treatment within the same temperature range, simplifying the process and saving energy. More importantly, co-diffusion in the austenitic state results in a much higher diffusion rate of elements than in the ferrite state, enabling the formation of a sufficiently deep functional subsurface layer within a limited time. Precise control of microstructure and properties: The isothermal quenching of bainite in step S2 avoids the high internal stress and brittleness risks caused by martensitic phase transformation in traditional quenching processes, directly obtaining a lower bainitic microstructure that combines high strength and high toughness. The localized post-weld tempering in step S4 precisely eliminates the adverse effects of welding thermal cycles on the weld and heat-affected zone, restores and enhances the toughness of the joint area, and ensures uniform performance of the entire chain link.

[0010] Preferably, in step S1, the mass percentage of the raw materials is: C: 0.38%~0.45%, Si: 1.5%~2.5%, Mn: 2.0%~3.0%, Cr: 0.8%~1.1%, Mo: 0.15%~0.25%; the forming process includes forming a closed-ring blank by hot rolling and forming an open main link blank by hot die forging, and then normalizing after forming.

[0011] Preferably, in step S2, the austenitizing treatment temperature is 880–920°C and the holding time is 60–90 minutes; the surface functionalization co-diffusion treatment uses vapor of a co-diffusion medium made of copper acetylacetone powder and cerium acetylacetone powder; the bainitic isothermal quenching temperature is 320–380°C and the holding time is 90–180 minutes.

[0012] Preferably, in step S2, the surface functionalization co-diffusion treatment is held for 120–240 minutes; after isothermal quenching of bainite, the volume fraction of retained austenite in the product is controlled to be 10%–15%. Through this method, the obtained retained austenite is not a structural defect, but rather the key to achieving high toughness. During the service life of the chain link, when subjected to impact loads or in high-stress areas such as crack tips, these metastable retained austenite undergo stress-induced phase transformation, transforming into high-strength martensite. This phase transformation process absorbs a large amount of energy and generates volume expansion, forming compressive stress at the crack tip, thereby effectively inhibiting crack initiation and propagation, endowing the material with excellent toughness and fatigue resistance, i.e., the TRIP effect (transformation-induced plasticity).

[0013] Preferably, in step S3, the joint area is preheated to 150–200°C by induction heating before welding; a special high-toughness welding wire composed of carbon, silicon, manganese, nickel, molybdenum, titanium, boron, and iron is used for welding, and a laser-arc hybrid welding system is employed. This method reduces the cooling rate of the welding zone, preventing the formation of hardened structures and hydrogen-induced cracks; the laser-arc hybrid welding, with its concentrated energy and low heat input, reduces the width of the heat-affected zone, thereby maximizing the protection of the excellent microstructure and properties of the base material.

[0014] Preferably, in step S4, the peak heating temperature for local tempering is 440–460°C, and the holding time is 100–140 seconds; after treatment, the impact absorption energy of the heat-affected zone is controlled to be no less than 70J at -20°C. This scheme precisely controls the tempering temperature and time, ensuring the effective elimination of welding residual stress and allowing any small amount of quenched martensite that may be generated in the heat-affected zone to be fully tempered into tough tempered sorbite, ultimately guaranteeing an extremely high level of low-temperature toughness in the welded joint in the form of performance indicators.

[0015] Preferably, a co-permeation medium for surface functionalization of tire protection chains is made from raw materials in the following mass ratio: copper acetylacetone powder: cerium acetylacetone powder = (9-11):1.

[0016] By employing the above technical solution, this invention utilizes the decomposition-deposition-diffusion mechanism of organometallic salts at high temperatures to form a functional subsurface layer on the surface of chain segments. Its innovative principle lies in:

[0017] Precursor selection: Copper acetylacetone and cerium acetylacetone were selected as precursors for co-diffusion. These two organometallic salts have low decomposition temperatures and can decompose at the temperature of austenitization treatment of chain segments, releasing highly reactive copper and cerium atoms.

[0018] Synergistic Mechanism of Elements: Step 1: Thermal Decomposition and Deposition: In a high-temperature and inert atmosphere, the co-diffusion medium vapor comes into contact with the hot chain link surface, causing copper acetylacetone and cerium acetylacetone to undergo thermal decomposition, depositing metal atoms onto the workpiece surface. Step 2: Diffusion and Solid Solution: The deposited active copper and cerium atoms rapidly diffuse into the austenitic matrix of the steel, forming a solid solution layer with a concentration gradient, i.e., a functional subsurface layer. Step 3: Functional Realization: The infiltrated copper element can act as a solid lubricant during wear, reducing the coefficient of friction; simultaneously, the rare earth element cerium can purify the surface grain boundaries and form high-melting-point dispersed particles with impurity elements in the steel, effectively pinning grain boundaries and refining the surface structure, thereby significantly improving the wear resistance and toughness of the subsurface layer.

[0019] Preferably, the preparation method of the co-permeation medium includes: placing copper acetylacetone powder and cerium acetylacetone powder in a vacuum drying oven and drying them at 50-70°C for 3-5 hours, followed by mechanical mixing under an inert atmosphere for 50-70 minutes.

[0020] Preferably, a welding wire for welding tire protection chains comprises the following components by mass percentage: carbon: 0.10%–0.14%; silicon: 0.50%–0.60%; manganese: 1.20%–1.40%; nickel: 2.10%–2.30%; molybdenum: 0.25%–0.35%; titanium: 0.07%–0.09%; boron: 0.002%–0.004%; and the balance being iron and impurities. By adopting the above technical solution, the welding wire provided by this invention achieves a precise match between the weld metal properties and the high-strength, high-toughness base material through precise alloy composition design. Its technical principle lies in:

[0021] Synergistic effect of low carbon and high toughness elements: By controlling the carbon content at a low level of 0.10% to 0.14%, the weld metal is guaranteed to have excellent welding process performance and crack resistance, while avoiding the formation of brittle structures such as high carbon martensite. On this basis, 2.10% to 2.30% nickel is added. As a key toughness-enhancing element, nickel can significantly improve the impact toughness of the weld metal at low temperatures, ensuring the reliability of the protective chain under harsh working conditions.

[0022] The strengthening and toughening effect of microalloying: Titanium and boron are added for microalloying. Titanium can effectively fix nitrogen in the weld, forming dispersed TiN particles, which can refine the grains and inhibit grain growth; trace amounts of boron can significantly improve the hardenability of steel and segregate at the grain boundaries, strengthening the grain boundaries, thereby further improving the toughness of the weld while ensuring strength.

[0023] Balance of overall performance: Silicon and manganese, as solid solution strengthening and deoxidizing elements, work together with molybdenum to ensure that the weld metal has sufficient strength and resistance to tempering softening, so that its mechanical properties match those of the base material after bainitic isothermal quenching, thus preventing the weld area from becoming the performance bottleneck of the entire chain.

[0024] Preferably, the method for preparing the welding wire includes the following steps: melting the above-mentioned raw materials in a vacuum arc melting furnace to obtain an alloy ingot; subjecting the alloy ingot to homogenization annealing treatment at 1050-1150°C for 8-16 hours; and subjecting the annealed ingot to multiple hot rolling and cold drawing processes to finally prepare a welding wire with a diameter of 1.0-1.4 mm.

[0025] This invention provides a manufacturing process for an ultra-strong wear-resistant tire protection chain. It has the following beneficial effects:

[0026] 1. This invention employs a high-silicon, high-manganese bainitic steel composition system and combines it with an isothermal quenching process in the bainitic transformation zone after austenitization to obtain a composite microstructure of carbide-free bainite and stable retained austenite in the matrix. This microstructure endows the chain links with extremely high matrix strength and fracture toughness, solving the problems of insufficient toughness and easy brittle fracture in traditional quenched martensitic steel chain links, and significantly improving the load-bearing capacity and reliability of the protective chain under complex impact loads.

[0027] 2. This invention achieves a functional sub-surface layer on the chain link surface by simultaneously performing surface functionalization co-diffusion treatment with copper and cerium elements during the austenitization process. This layer possesses high hardness, high wear resistance, and self-lubricating properties. This solution resolves the contradiction between core toughness and surface wear resistance that cannot be simultaneously achieved through single heat treatment. By constructing a performance gradient, it significantly improves the wear resistance of the protective chain and extends its service life under harsh abrasive conditions.

[0028] 3. This invention employs a specially designed low-carbon, high-toughness welding wire, combined with laser-arc hybrid welding with precise heat input control and post-weld local tempering, to accurately regulate the microstructure and properties of the welded joint and heat-affected zone. This solution solves the problem that traditional welding methods easily lead to performance degradation in the joint area, making it a weak link in the entire chain. It ensures that the weld area has excellent low-temperature toughness matching the base material, thereby guaranteeing the structural integrity and final service safety of the entire tire protection chain. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the wear of the chain link cross section according to the present invention;

[0030] Figure 2 This is a schematic diagram of the fatigue crack propagation rate curve of the present invention;

[0031] Figure 3 This is a schematic diagram comparing the macroscopic mechanical properties of the present invention;

[0032] Figure 4 This is a schematic diagram comparing the wear resistance of the present invention;

[0033] Figure 5 This is a schematic diagram comparing the high-cycle fatigue performance of the present invention;

[0034] Figure 6 This is a schematic diagram comparing the overall performance of the welded joints of the present invention. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0036] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0037] Industrial pure iron, grade DT4, conforms to GB / T-6983-2008 standard, in lumps or ingots, with the chemical formula Fe and CAS number 7439-89-6; electrolytic manganese, conforms to GB / T-2774-2016 standard, in flakes, with a manganese content of not less than 99.7%, with the chemical formula Mn and CAS number 7439-96-5; metallic silicon, conforms to GB / T-2881-2014 standard, in lumps, with a silicon content of not less than 99.5%, with the chemical formula Si. CAS No. 7440-21-3; Metallic chromium, conforming to GB / T-3213-2008 standard, in block form, with a chromium content of not less than 99.5%, its chemical formula is Cr, CAS No. 7440-47-3; Metallic molybdenum, conforming to GB / T-3461-2007 standard, in strip or block form, with a molybdenum content of not less than 99.5%, its chemical formula is Mo, CAS No. 7439-98-7; Graphite powder, high purity grade, with a carbon content of not less than 99.9%, its chemical formula is C, C AS number 7782-42-5; electrolytic nickel, conforming to GB / T-6516-2010 standard, in plate form, with a nickel content of not less than 99.9%, its chemical formula is Ni, CAS number 7440-02-0; sponge titanium, conforming to GB / T-2524-2019 standard, with a titanium content of not less than 99.5%, its chemical formula is Ti, CAS number 7440-32-6; ferroborone alloy, conforming to GB / T-5682-2017 standard, wherein the boron content is 15%-20%. %; Copper acetylacetone, a blue crystalline powder with the chemical formula Cu(C5H7O2)2 and CAS number 13395-16-9; Cerium acetylacetone, usually in its hydrated form, is a pale yellow powder with the chemical formula Ce(C5H7O2)3·xH2O and CAS number 15653-01-7; High-purity argon, conforming to GB / T-10624-2019 standard, with a purity of not less than 99.99%, has the chemical formula Ar and CAS number 7440-37-1.

[0038] Preparation Examples 1-2:

[0039] Preparation Example 1: Preparation of Surface-Functionalized Co-diffusion Media

[0040] Take copper acetylacetone powder with CAS number 13395-16-9 and cerium acetylacetone powder with CAS number 15653-01-7, place them in a vacuum drying oven and dry at 60°C for 4 hours; after drying, weigh them accurately at a mass ratio of 10:1, transfer them to a ball mill, and mechanically mix them for 60 minutes under an argon atmosphere to obtain a uniform light green mixed powder; store the mixed powder in a sealed container filled with dry nitrogen, label it as co-permeation agent A, and keep it for later use.

[0041] Preparation Example 2: Preparation of Special High-Toughness Welding Wire

[0042] The raw materials were prepared according to the chemical composition (mass fraction) listed in the table below, and all raw materials were the aforementioned industrial raw materials. The prepared materials were melted in a vacuum arc melting furnace using a water-cooled copper crucible. To ensure uniform composition, the melting was repeated more than three times to obtain an alloy ingot. Subsequently, the ingot was subjected to homogenization annealing at 1100℃ for 12 hours. After annealing, the ingot underwent multiple hot rolling and cold drawing processes, followed by intermediate annealing, and was finally prepared into a smooth solid welding wire with a diameter of 1.2 mm. This welding wire was marked as HZ-1 and kept for later use.

[0043] Table 1: Chemical composition (wt%) of HZ-1 welding wire

[0044]

[0045] Examples 1-3:

[0046] Example 1:

[0047] This embodiment provides a manufacturing process for an ultra-strong wear-resistant tire protection chain, including the following steps:

[0048] Melting and forming: According to the mass fraction, C: 0.42%, Si: 2.0%, Mn: 2.5%, Cr: 1.0%, Mo: 0.2%, with the balance being Fe and unavoidable impurities, the raw materials are batched and melted in a vacuum induction melting furnace, and then cast into steel ingots; after heating the steel ingots to 1200℃, they are respectively made into closed-ring blanks by hot rolling process and into open main chain section blanks by hot die forging process. After forming, the blanks are normalized.

[0049] Integrated heat treatment: Surface functionalization co-diffusion treatment was performed using an embedding method. The chain link blank was placed in a sealed diffusion agent box, and co-diffusion agent A prepared in Preparation Example 1 was used as the main diffusion agent, with inert alumina powder as the filler. The two were mixed evenly at a mass ratio of 1:3, and the chain link blank was completely embedded in the mixed powder. Subsequently, the sealed diffusion agent box was placed in a box-type resistance furnace preheated to 900°C and held for 180 minutes. During this process, co-diffusion agent A inside the box decomposed / sublimated upon heating, forming a high concentration of active vapor in the sealed space, which directly contacted the surface of the chain link blank for co-diffusion treatment. After treatment, the workpiece was quickly removed from the diffusion agent box and transferred to a nitrate bath furnace at 350°C for isothermal holding for 150 minutes to complete the bainitic phase transformation. Afterward, it was removed and air-cooled to room temperature.

[0050] Assembly and welding: The heat-treated closed ring is inlaid into the opening of the open main link; the joint area is preheated to 180°C by induction heating; the opening is welded closed using a laser-arc hybrid welding system and the HZ-1 welding wire prepared in Preparation Example 2.

[0051] Post-weld local heat treatment: After welding, the weld and heat-affected zone are immediately tempered using a mobile induction heating device. The peak heating temperature is 450℃, and the temperature is held for 120 seconds, followed by natural cooling in the air.

[0052] Example 2:

[0053] This embodiment provides a manufacturing process for an ultra-strong wear-resistant tire protection chain, including the following steps:

[0054] Melting and forming: According to the mass fraction, C: 0.45%, Si: 2.5%, Mn: 3.0%, Cr: 1.1%, Mo: 0.25%, with the balance being Fe and unavoidable impurities, the ingredients were batched and melted. The subsequent forming process was the same as in Example 1.

[0055] Integrated heat treatment: The workpiece was austenitized in an argon atmosphere at 920°C and held for 90 minutes; then, vapor of co-diffusion agent A prepared in Preparation Example 1 was introduced and the workpiece was held at this temperature for another 240 minutes; after the treatment, the workpiece was quickly transferred into a nitrate bath furnace at 320°C and held isothermally for 180 minutes, and then removed and air-cooled.

[0056] Assembly and welding: Same as step 3 in Example 1;

[0057] Post-weld local heat treatment: Same as step 4 in Example 1.

[0058] Example 3:

[0059] This embodiment provides a manufacturing process for an ultra-strong wear-resistant tire protection chain, including the following steps:

[0060] Melting and forming: According to the mass fraction, C: 0.38%, Si: 1.5%, Mn: 2.0%, Cr: 0.8%, Mo: 0.15%, with the balance being Fe and unavoidable impurities, the ingredients were batched and melted. The subsequent forming process was the same as in Example 1.

[0061] Integrated heat treatment: The workpiece was austenitized in an argon atmosphere at 880°C and held for 60 minutes; then, vapor of co-diffusion agent A prepared in Preparation Example 1 was introduced and the workpiece was held at this temperature for another 120 minutes; after the treatment, the workpiece was quickly transferred into a nitrate bath furnace at 380°C and held isothermally for 90 minutes, and then removed and air-cooled.

[0062] Assembly and welding: Same as step 3 in Example 1;

[0063] Post-weld local heat treatment: Same as step 4 in Example 1.

[0064] Comparative Examples 1-4:

[0065] Comparative Example 1:

[0066] This comparative example provides a tire protection chain manufactured using conventional processes. Compared with Example 1, the difference is that the base material is commercially available 42CrMo steel; the heat treatment process is conventional quenching at 860℃ followed by tempering at 580℃, without any surface co-diffusion step; ordinary J507 welding rods are used for welding, and there is no post-weld local heat treatment.

[0067] Comparative Example 2:

[0068] Compared with Example 1, the difference is that the co-diffusion step of introducing co-diffusion agent A vapor is omitted in the integrated heat treatment steps. Only austenitization (900°C, holding for 260 minutes) and subsequent bainitic isothermal quenching (350°C, holding for 150 minutes) are performed. The rest are the same.

[0069] Comparative Example 3:

[0070] Compared with Example 1, the differences are as follows: the base material is commercially available 42CrMo steel; the integrated heat treatment steps are replaced by: first performing the same co-diffusion treatment as in Example 1, but then not performing bainitic isothermal quenching, but performing traditional quenching and tempering treatment of oil quenching at 860°C and high-temperature tempering at 580°C; ordinary J507 welding rods are used for welding, and there is no post-weld local heat treatment.

[0071] Comparative Example 4:

[0072] Compared with Example 1, the difference is that: in the assembly and welding steps, ordinary J507 welding rods are used instead of HZ-1 welding wire prepared in Preparation Example 2; and the post-weld local heat treatment step is omitted.

[0073] Test Examples 1-6:

[0074] Test Example 1: Wear Visualization Warning Function Trigger Test

[0075] This test example is used to verify whether the tire protection chain component prepared by the process of the present invention can produce a visually identifiable color change on its surface after reaching a preset wear depth, so as to confirm the feasibility of the wear indication function.

[0076] The testing steps are as follows:

[0077] Sample preparation: Three links prepared in Example 1 were selected and labeled as 1-1, 1-2, and 1-3; one link prepared in Comparative Example 2 (which used the steel and isothermal quenching process of this invention, but did not undergo surface functionalization co-diffusion treatment) was selected and labeled as D-2.

[0078] Testing equipment: The M-2000 abrasive wear tester was used. The grinding wheel was a neoprene rubber wheel, and the abrasive was quartz sand with a particle size between 0.1-0.3 mm. A laser displacement sensor was also used to monitor the wear depth in real time.

[0079] Test execution: Fix the sample on the test machine fixture, set the normal load of the grinding wheel to 50N and the rotation speed to 200r / min; start the test machine to grind the surface of each sample; during the grinding process, continuously monitor the depth change of the wear area through a laser displacement sensor;

[0080] Results observation: When the laser displacement sensor reading shows that the wear depth of any sample reaches 1.50 mm for the first time, the test of that sample is stopped immediately; the sample is taken out, cleaned with deionized water and dried, and the surface color and condition of the wear area are visually inspected and recorded under natural light conditions using a D65 standard light source.

[0081] Test data is shown in Table 2:

[0082] Table 2: Test Results of Wear Visualization Early Warning Function

[0083]

[0084] Conclusion: Refer to Appendix Figure 1 The test results showed that the samples prepared by the process of Example 1 all produced a clear and uniform blue-green layer on their surface after the wear depth reached the preset threshold; in contrast, the sample of Comparative Example 2, which did not undergo surface functionalization co-diffusion treatment, did not show any color change on its surface after reaching the same wear depth.

[0085] The mechanism behind this phenomenon is as follows: the austenitization and multi-element co-diffusion steps in the process form a functional layer rich in copper (Cu) and cerium (Ce) in the subsurface layer (1.0-2.0 mm depth) of the workpiece. During normal service life, this functional layer is covered by the external steel substrate and is stable in nature. When wear reaches and exceeds this depth, this functional layer is exposed to the external environment. The intermetallic compounds of copper and cerium in the layer undergo oxidation-hydration reactions with oxygen and moisture in the air to generate a brightly colored complex mainly composed of copper salts / oxides, which macroscopically appears as a blue-green visual indicator.

[0086] The test results confirm that the technical solution of this invention, which constructs a functional subsurface layer inside the material matrix to achieve visual early warning of wear status, is feasible. It provides an objective means to determine the remaining life of a component without the need for external instruments, and solves the technical problem in the prior art that the wear status of tire protection chains is unknown and relies on subjective experience.

[0087] Test Example 2: Verification Test of Dynamic Crack Arrest Effect

[0088] This test case aims to verify, by quantitatively evaluating the crack propagation resistance of the material under cyclic loading, whether the tire protection chain matrix material prepared by the process of this invention has the ability to arrest dynamic cracks due to the phase transformation induced plasticity (TRIP) effect.

[0089] The testing steps are as follows:

[0090] Sample preparation: Compact tensile (CT) specimens conforming to ASTM-E647 were machined from finished chain links of Example 1 and Comparative Example 3 (which used conventional 42CrMo steel and underwent surface functionalization co-diffusion treatment, and the matrix did not have the TRIP effect) by wire EDM. All specimens were finely ground and polished to ensure dimensional accuracy and surface finish.

[0091] Testing equipment: The MTS-Landmark-370.10 electro-hydraulic servo fatigue testing machine was used, equipped with a high-precision dynamic extensometer for measuring crack opening displacement, and a high-magnification reading microscope for in-situ observation of crack length.

[0092] Pre-crack initiation: Fatigue pre-cracks were initiated at the root of the V-notch of all CT specimens by applying high-frequency, low-amplitude cyclic loading, with the length of the pre-crack controlled between 2.0 and 2.5 mm.

[0093] Test execution: The pre-cracked specimen is mounted on a fatigue testing machine and a sinusoidal alternating load with a constant stress ratio (R=0.1) is applied; the test is conducted using the ΔK value decreasing method, starting from a higher stress intensity factor range, and the load amplitude is gradually reduced according to the standard after each crack propagation of a certain length; throughout the test, the load, number of cycles (N) and crack length (a) are recorded simultaneously.

[0094] Data processing: Based on the recorded raw data of aN, the fatigue crack propagation rate (da / dN) under different crack lengths is calculated using the seven-point incremental polynomial method; at the same time, the corresponding stress intensity factor range (ΔK) is calculated based on the corresponding load and crack length.

[0095] Test data are shown in Table 3:

[0096] Table 3: Comparison of fatigue crack propagation rates test data

[0097]

[0098] Conclusion: Refer to Appendix Figure 2The test results show that, under the same stress intensity factor range (ΔK), the sample prepared by the process of Example 1 has a significantly lower fatigue crack propagation rate (da / dN) than the sample prepared by the process of Comparative Example 3; especially in the low ΔK value range near the threshold region, the sample of Example 1 exhibits higher crack propagation resistance.

[0099] The underlying mechanism of this phenomenon lies in the fact that the matrix material of Example 1, through specific chemical composition design and bainitic isothermal quenching process, retains 10%-15% metastable retained austenite in its microstructure. When fatigue cracks initiate and propagate under cyclic loading, a high stress concentration occurs in the crack tip region. This stress field induces a martensitic phase transformation in the metastable retained austenite near the crack tip. Since the specific volume of martensite is greater than that of austenite, this phase transformation process is accompanied by significant volume expansion. This volume expansion generates a strong local compressive stress field in the crack tip region. This compressive stress field can effectively offset part of the external tensile stress, producing a crack tip closure effect, thereby blunting the crack tip and increasing the energy required for the crack to continue propagating.

[0100] The test results confirm that the technical solution of this invention, which achieves dynamic crack arrest by constructing a TRIP effect microstructure inside the material, is feasible; it endows the material with an intrinsic passive defense capability against damage, and solves the technical problem that traditional high-hardness wear-resistant materials are prone to brittle fracture due to insufficient toughness when bearing impact and cyclic loads.

[0101] Test Example 3: Macroscopic Mechanical Property Testing

[0102] This test case aims to quantitatively evaluate the comprehensive performance level of tire protection chain matrix materials prepared by the process of the present invention (Examples 1-3) and different control processes (Comparative Examples 1-4) in terms of hardness, strength, plasticity and toughness by systematically testing the basic mechanical properties of the materials.

[0103] The testing steps are as follows:

[0104] Sample preparation: Samples were taken from the non-welded areas of the finished chain links of Examples 1-3 and Comparative Examples 1-4 and processed into standard specimens for various tests; the sampling location and processing technology of all specimens were kept consistent to eliminate the influence of irrelevant variables;

[0105] Hardness test: According to GB / T-230.1-2018 standard, the hardness of the original surface of the sample was measured using an HR-150A Rockwell hardness tester; five different locations were selected for testing each sample, and the arithmetic mean of the results was taken.

[0106] Tensile property testing: According to GB / T-228.1-2021 standard, the samples were processed into standard tensile specimens with a circular cross-section; using a WDW-300 electronic universal testing machine, the test was conducted at a constant tensile rate of 2 mm / min at room temperature, and the tensile strength was recorded. ) and elongation at break (δ);

[0107] Impact toughness test: According to GB / T-229-2020 standard, the sample is processed into a standard V-notch Charpy impact test specimen of 10mm×10mm×55mm; the specimen is cooled in a low temperature constant temperature bath and kept at -20±1℃, and then quickly transferred to a JB-300B pendulum impact testing machine for impact test, and its impact absorption energy (Akv) is recorded.

[0108] The test data is shown in Table 4.

[0109] Table 4: Results of Macroscopic Mechanical Properties Test

[0110]

[0111] Conclusion: Refer to Appendix Figure 3 The test data also showed that the samples in Examples 1-3 maintained high surface hardness (49.8-54.2HRC) and high tensile strength (1710-1860MPa), while exhibiting excellent low-temperature impact toughness (74-89J) and good elongation after fracture (13.5%-15.1%).

[0112] The underlying mechanism of this performance is that the bainitic / retained austenitic composite structure formed by the integrated heat treatment process adopted in this invention has both high strength and high toughness. Among them, the carbide-free bainitic ferrite laths provide the material with high strength and hardness, while the metastable retained austenite dispersed therein absorbs a large amount of energy through the phase transformation induced plasticity (TRIP) effect when the material is subjected to stress and deformation, thereby improving the plasticity and toughness of the material, especially the ability to suppress brittle fracture at low temperature.

[0113] In contrast, Comparative Examples 1 and 3 used traditional quenched and tempered steel. Although their tempered martensitic structure had good comprehensive properties, their low-temperature impact toughness was significantly lower than that of the embodiments of the present invention at the same hardness level. The matrix properties of Comparative Examples 2 and 4 were basically the same as those of Example 1, which indicates that the surface co-diffusion treatment and subsequent welding process did not have a deteriorating effect on the macroscopic mechanical properties of the matrix material.

[0114] The test results confirm that the manufacturing process of this invention can give the tire protection chain a combination of strength and toughness that surpasses traditional quenched and tempered steel. This solves the technical problem that traditional wear-resistant materials often sacrifice toughness while pursuing high hardness and high strength, leading to early failure under complex impact conditions.

[0115] Test Example 4: Comparison Test of Wear Resistance

[0116] This test case aims to quantitatively compare the performance differences in resistance to abrasive wear between samples prepared by the process of this invention and those prepared by various comparative processes by simulating abrasive wear conditions.

[0117] The testing steps are as follows:

[0118] Sample preparation: Cut block-shaped samples with dimensions of 30mm×15mm×10mm from the finished chain links of Examples 1-3 and Comparative Examples 1-4; ensure that the test surface of the sample is the original surface after heat treatment.

[0119] Pre-test treatment: All samples were ultrasonically cleaned in acetone solution for 15 minutes to remove surface oil, and then dried in a drying oven at 80°C for 2 hours; after cooling to room temperature, the initial mass of each sample was weighed using an analytical balance with an accuracy of 0.1 mg and recorded. ).

[0120] Testing equipment: ML-10 wet rubber wheel abrasive wear tester; test parameters were set as follows: rubber wheel speed 240 r / min, normal load 70 N, abrasive was quartz sand with a particle size of 150-250 μm, and abrasive slurry mass concentration was 30%.

[0121] Test execution: The specimen is clamped on the testing machine, the equipment is started and the abrasive slurry is dripped; the wear test duration for each specimen is 30 minutes;

[0122] Post-test processing: After the test, the sample was removed and ultrasonically cleaned again to thoroughly remove the abrasive adhering to the surface. It was then dried and cooled to room temperature. The final mass was weighed using the same analytical balance and recorded. ); mass loss per sample ( )pass The calculation yielded the result.

[0123] Test data is shown in Table 5:

[0124] Table 5: Comparison Test Results of Wear Resistance Performance

[0125]

[0126] Conclusion: Refer to Appendix Figure 4The test results show that the wear mass loss of the samples in Examples 1-3 is significantly reduced compared with that of Comparative Examples 1 and 3; this result verifies the effectiveness of the process of the present invention in improving the wear resistance of materials.

[0127] Its underlying mechanism is mainly attributed to the following aspects: the matrix material prepared by the process has high surface hardness, which is the primary factor in resisting abrasive cutting and ploughing; the high-hardness matrix without carbide bainite provides an excellent anti-wear foundation for the material; the metastable retained austenite in the material microstructure undergoes a phase transformation to martensite under the stress-strain action generated by the extrusion and cutting of abrasive particles; this dynamic, in-situ surface strengthening process can continuously compensate for material loss caused by wear and further improve the surface hardness and wear resistance; the cerium (Ce) element introduced in the surface functionalization co-diffusion step exists in the subsurface as a dispersed rare earth compound, and these particles can pin grain boundaries and hinder dislocation movement, thereby improving the toughness of the surface material, inhibiting the initiation and propagation of microcracks during the wear process, and thus reducing material spalling;

[0128] The wear of Comparative Example 2 (without co-diffusion treatment) was slightly higher than that of Example 1, which confirms the auxiliary effect of the surface functionalized layer on wear resistance. Comparative Examples 1 and 3 used conventional quenched and tempered steel, whose hardness level and microstructure were insufficient to resist high-intensity abrasive wear, thus exhibiting a large mass loss.

[0129] The test results confirm that the process of the present invention, through the synergistic effect of tissue regulation and surface modification, can endow the tire protection chain with superior wear resistance and solve the technical problem of its failure due to rapid wear under harsh working conditions.

[0130] Test Example 5: High-cycle fatigue performance comparison test

[0131] This test case aims to quantitatively compare the differences in high-cycle fatigue performance between samples prepared by the process of the present invention (Examples 1-3) and different control processes (Comparative Examples 1-4) by evaluating the fatigue failure resistance of materials under repeated cyclic loading.

[0132] The testing steps are as follows:

[0133] Sample preparation: Rotational bending fatigue specimens conforming to GB / T-4337-2015 standard were prepared from the non-welded areas of the finished chain links of Examples 1-3 and Comparative Examples 1-4 by wire cutting and machining; all specimens were machined into smooth circular cross sections, and the test areas were finely ground and polished to eliminate the influence of surface defects on fatigue performance.

[0134] Testing equipment: PQ-6 type rotary bending fatigue testing machine; this equipment can apply uniform bending stress to the specimen, and the stress ratio R is set to -1 (completely symmetrical cycle).

[0135] Test execution: The specimens are precisely mounted on the fatigue testing machine; constant stress loads of different amplitudes are applied, and the number of cycles at which each specimen reaches failure (fracture) is recorded; for specimens reaching 10 cycles... 7 Samples that do not fail after one test are defined as "run-out"; the staircase method is used to test each group of samples to efficiently determine their performance at 10°C. 7 Fatigue limit under the next cycle ( ).

[0136] Data recording: Record the stress amplitude and corresponding failure cycle number or failure result of each specimen.

[0137] Test data is shown in Table 6:

[0138] Table 6: Comparative Test Results of High-Cycle Fatigue Performance

[0139]

[0140] Conclusion: Refer to Appendix Figure 5 And the test results show that the samples of Examples 1-3 are at 10 7 Fatigue limit under the next cycle ( The pressure (approximately 640-720 MPa) was significantly higher than that of comparative examples 1 and 3. The fatigue limits of Comparative Example 2 (without co-diffusion) and Comparative Example 4 (different welding processes, but the matrix material was tested here) are close to those of Examples 1-3, which indicates that the co-diffusion treatment itself and the subsequent welding operation (if the impact on the matrix region is limited) have no significant negative impact on the high-cycle fatigue performance of the matrix material.

[0141] The underlying mechanism of this performance advantage lies in the unique bainite / retained austenite composite microstructure of the matrix material prepared by the process. Under cyclic loading, during the microscopic plastic deformation stage of crack initiation and the short crack propagation stage, the metastable retained austenite in the material can transform into martensite through stress-induced phase transformation. This phase transformation generates local volume expansion and compressive stress at the crack tip, effectively inhibiting crack initiation and propagation. On the other hand, the martensitic phase transformation itself is also an energy-consuming process, which can absorb the energy accumulated during cyclic loading, thereby improving the material's resistance to fatigue damage. In addition, the fine lath structure of the bainite microstructure also provides favorable conditions for improving fatigue strength.

[0142] The traditional quenching and tempering process used in Comparative Examples 1 and 3 typically produces tempered martensite microstructure, which, although possessing high strength, exhibits inferior toughness and resistance to crack initiation and propagation under cyclic loading compared to bainite / retained austenite microstructure with the TRIP effect.

[0143] The test results confirm that the manufacturing process of the present invention can significantly improve the high-cycle fatigue performance of tire protection chain materials, solve the technical problem of early failure caused by fatigue accumulation damage under long-term complex loads of traditional materials, and thus extend the service life of the components.

[0144] Test Example 6: Comprehensive Performance Test of Welded Joints

[0145] This test case aims to verify the effectiveness of the special welding wire and post-weld local heat treatment process used in this invention in ensuring the mechanical properties of the welded joint match the base material by quantitatively evaluating the tensile strength and impact toughness of the heat-affected zone (HAZ) of the welded joint.

[0146] The testing steps are as follows:

[0147] Sample preparation: Wire cutting was performed on welded chain links prepared in Example 1 and Comparative Example 4 (which used the same substrate and heat treatment process as Example 1, but used ordinary welding rods and did not undergo post-weld local tempering) to obtain the following two types of samples:

[0148] Tensile test specimens for welded joints: The specimens are processed into flat tensile test specimens conforming to GB / T-2651-2008, ensuring that the weld is located in the center of the gauge length of the specimen and perpendicular to the tensile direction; 3 specimens are selected for each group.

[0149] Heat-affected zone impact test specimens: processed into V-notch Charpy impact test specimens conforming to GB / T-2650-2008 standard; by precisely controlling the cutting position, ensure that the V-notch is located in the center of the heat-affected zone (HAZ) on both sides of the weld; 3 specimens are selected for each group.

[0150] Tensile test of welded joint: The tensile test specimens of welded joint were tested at room temperature using a WDW-300 electronic universal testing machine in accordance with the GB / T-2651-2008 standard. The specimens were loaded at a constant tensile rate of 2 mm / min until fracture. The fracture load of each specimen was recorded, the tensile strength of the welded joint was calculated, and the fracture location was observed.

[0151] Heat-affected zone impact test: The JB-300B pendulum impact testing machine was used to test the HAZ impact specimens according to the GB / T-2650-2008 standard. The specimens were kept in a low temperature constant temperature bath at -20±1℃ for at least 15 minutes, and then quickly transferred to the impact testing machine for impact test. The impact absorption energy (Akv) of each specimen was recorded.

[0152] Test data is shown in Table 7:

[0153] Table 7: Test Results of Comprehensive Performance of Welded Joints

[0154]

[0155] Conclusion: Refer to Appendix Figure 6 The test results show that the welded chain links prepared by the process of the present invention (Example 1) have a tensile strength of welded joints that is close to that of the base material (approximately 1710-1785 MPa, see Table 4), and the fracture locations mostly occur in the base material or heat-affected zone, indicating that the strength of the weld itself is higher than or matches that of the HAZ and the base material; at the same time, the impact absorption energy (72-78 J) of its heat-affected zone at -20℃ remains at a high level.

[0156] In contrast, the welded chain links of Comparative Example 4 have significantly lower tensile strength at the welded joints than those of Example 1, and the fracture locations are all located in the weld. The impact absorption energy of the heat-affected zone of Comparative Example 4 is also greatly reduced, only 28-35J.

[0157] The underlying mechanism of this performance difference lies in the compatibility of the special welding wire: The HZ-1 special welding wire used in Example 1 and Preparation Example 2 has an optimized chemical composition that matches the melting point, phase transformation behavior, and mechanical properties of the steel of the present invention; this welding wire can effectively suppress the formation of harmful phases during the welding process and form a good metallurgical bond with the base material, ensuring the strength and toughness of the weld; while the ordinary welding rod used in Comparative Example 4 has a composition that does not match the base material, which easily leads to weld embrittlement or insufficient strength. The optimizing effect of post-weld local heat treatment: In Example 1, the post-weld local tempering treatment precisely controlled the heating temperature and holding time of the weld and HAZ region. This process can effectively refine the weld microstructure, eliminate residual welding stress, and promote the phase transformation of coarse or brittle microstructures in the HAZ caused by welding thermal cycling, forming a finer and more uniform bainite / austenite microstructure, thereby significantly improving the impact toughness and comprehensive mechanical properties of the HAZ. Comparative Example 4 lacked this key step, resulting in the failure to effectively optimize the coarse grains or martensite microstructure formed in the HAZ due to welding thermal cycling, thus exhibiting lower toughness.

[0158] The test results confirm that the special welding process (including special welding wire and post-weld local heat treatment) used in this invention is effective and can ensure that the welded joint has mechanical properties that match the base material. It solves the technical problem that traditional welding methods often cause embrittlement of the weld or heat-affected zone when welding high-strength and tough steel, leading to joint performance deterioration and early failure.

[0159] 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. A manufacturing process for an ultra-strong wear-resistant tire protection chain, characterized in that, Includes the following steps: S1. Melt the raw materials containing the following mass percentages and shape them into chain link blanks: C: 0.35%~0.50%, Si: 1.0%~3.0%, Mn: 1.5%~3.5%, Cr: 0.5%~1.5%, Mo: 0.10%~0.30%, with the balance being Fe and unavoidable impurities; S2. The chain link blank is subjected to austenitization treatment at 850-950℃ and held for 50-100 minutes. Then, surface functionalization co-diffusion treatment is performed at the austenitization temperature and held for 100-300 minutes. After the treatment, bainitic isothermal quenching is performed at 300-400℃ and held for 60-240 minutes. S3. Assemble the heat-treated chain links and weld the opening closed. S4. Perform local tempering treatment on the weld and heat-affected zone at 400-500℃ and hold for 60-180 seconds.

2. The manufacturing process of an ultra-strong wear-resistant tire protection chain according to claim 1, characterized in that, In step S1, the mass percentage of the raw materials is: C: 0.38%~0.45%, Si: 1.5%~2.5%, Mn: 2.0%~3.0%, Cr: 0.8%~1.1%, Mo: 0.15%~0.25%; the forming process includes forming a closed-ring blank by hot rolling and forming an open main link blank by hot die forging, and then normalizing after forming.

3. The manufacturing process of an ultra-strong wear-resistant tire protection chain according to claim 1, characterized in that, In step S2, the austenitizing treatment temperature is 880-920℃ and the holding time is 60-90 minutes; the surface functionalization co-diffusion treatment uses vapor of a co-diffusion medium made of copper acetylacetone powder and cerium acetylacetone powder; the bainitic isothermal quenching temperature is 320-380℃ and the holding time is 90-180 minutes.

4. The manufacturing process of an ultra-strong wear-resistant tire protection chain according to claim 3, characterized in that, The co-permeation medium is made from raw materials in the following mass ratio: copper acetylacetone powder: cerium acetylacetone powder = (9-11):

1.

5. The manufacturing process of an ultra-strong wear-resistant tire protection chain according to claim 4, characterized in that, The preparation method of the co-permeation medium includes: Copper acetylacetone powder and cerium acetylacetone powder were placed in a vacuum drying oven and dried at 50-70°C for 3-5 hours, followed by mechanical mixing under an inert atmosphere for 50-70 minutes.

6. The manufacturing process of an ultra-strong wear-resistant tire protection chain according to claim 1, characterized in that, The surface functionalization co-diffusion treatment in step S2 is held for 120 to 240 minutes; after the bainite isothermal quenching, the volume fraction of the residual austenite in the product is controlled to be 10% to 15%.

7. The manufacturing process of an ultra-strong wear-resistant tire protection chain according to claim 1, characterized in that, In step S3, the joint area is preheated to 150-200°C by induction heating before welding; a special high-toughness welding wire is used for welding, and a laser-arc hybrid welding system is used.

8. The manufacturing process of an ultra-strong wear-resistant tire protection chain according to claim 7, characterized in that, The special high-toughness welding wire is composed of the following components by weight percentage: Carbon: 0.10%–0.14%; Silicon: 0.50%–0.60%; Manganese: 1.20%~1.40%; Nickel: 2.10%–2.30%; Molybdenum: 0.25%–0.35%; Titanium: 0.07%~0.09%; Boron: 0.002%–0.004%; And the remaining iron and impurities.

9. The manufacturing process of an ultra-strong wear-resistant tire protection chain according to claim 8, characterized in that, The method for preparing the welding wire includes the following steps: The alloy ingot is obtained by melting carbon, silicon, manganese, nickel, molybdenum, titanium, boron and the balance of iron in a vacuum electric arc melting furnace. The alloy ingot is subjected to homogenization annealing at 1050–1150°C for 8–16 hours; The annealed ingots are subjected to multiple hot rolling and cold drawing processes to finally produce welding wires with a diameter of 1.0 to 1.4 mm.

10. The manufacturing process of an ultra-strong wear-resistant tire protection chain according to claim 1, characterized in that, In step S4, the local tempering treatment involves a peak heating temperature of 440–460°C and a holding time of 100–140 seconds; after the treatment, the impact absorption energy of the heat-affected zone is controlled to be no less than 70J at -20°C.

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