Liquid-liquid composite ceramic inlay high wear-resistant pendulum and preparation method thereof

Abstract

The present application belongs to the technical field of ceramic alloy flywheel, and particularly relates to a liquid-liquid composite ceramic inlaid high-wear-resistance flywheel and a preparation method thereof, which is suitable for high-strength impact environment such as mines and metallurgy. The flywheel realizes metallurgical bonding of ceramic-metal by step-by-step pouring and temperature control solidification of basalt melt and high-density W-Ni-Fe alloy melt in a specific mold structure. The ceramic core is composed of multiple inorganic oxides and low-melting-point glass powder, and has excellent interface compatibility and structural stability. During the preparation process, the initial setting state of basalt and the alloy flow path are accurately controlled to improve the interface bonding strength and overall density. The finally obtained flywheel has high hardness, high toughness and excellent wear resistance, and significantly prolongs the service life.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ceramic alloy flywheels, and particularly relates to a liquid-liquid composite ceramic inlaid high-wear-resistance flywheel and a preparation method thereof. BACKGROUND

[0002] Flywheels are key and easily damaged components in various types of crushers, pulverizers and other equipment, and are mainly used for high-speed impact and crushing of materials. In actual operation, the flywheel is long-term in harsh working conditions such as high impact, high friction and strong corrosion, and is prone to failure phenomena such as wear, fracture and peeling, which seriously affects the operation efficiency and service life of the equipment. Therefore, improving the wear resistance and comprehensive service performance of the flywheel has become an important research direction in the field of materials and equipment.

[0003] Traditional flywheels are mostly made of single metal materials such as high manganese steel and high chromium cast iron. Although they have certain toughness or hardness advantages, they are difficult to balance high impact toughness and excellent wear resistance in actual application. Some improvement schemes try to improve the comprehensive performance through composite materials, surface strengthening or heat treatment technology, such as high chromium alloy and hard alloy composite, metal ceramic cladding, surfacing or spraying enhanced layer, but there are still problems such as insufficient structural bonding strength, easy interface peeling, complex process and high cost.

[0004] In recent years, liquid-liquid composite casting technology has attracted widespread attention because it can form a good metallurgical bonding interface during casting. However, the existing liquid-liquid composite casting technology has not been widely applied in the field of flywheels, especially in the design and stable forming of ceramic inlaid structure, including the fixing method of ceramic inserts, thermal stress matching, composite interface organization regulation and other problems.

[0005] Therefore, it is urgent to provide a liquid-liquid composite ceramic inlaid flywheel preparation method with reasonable structure design, firm composite interface and excellent wear resistance, to improve the service life and stability of the flywheel under complex working conditions, and provide a more efficient and reliable wear-resistant solution for the heavy-load crushing industry. SUMMARY

[0006] To solve the above problems, the purpose of the present application is to provide a preparation method of a liquid-liquid composite ceramic inlaid high-wear-resistance flywheel, comprising the following steps:

[0007] S1, mold preparation, preheat the metal mold to 150-250 DEG C; the metal mold has an upper end conical cavity and a lower end rectangular cavity inside and a stepped platform with a width of 10-20 cm at the junction thereof;

[0008] S2, ceramic core installation, insert the ceramic core into the junction positioning groove and make the top 2.0-10.0 cm higher than the groove opening;

[0009] S3, first pouring, pouring basalt melt at 1450-1500℃ into the upper conical cavity under the condition of vacuum degree 0.06-0.09 MPa to form a primary shell with thickness 2-10 mm;

[0010] S4, second pouring, pouring W-Ni-Fe alloy melt obtained by smelting 93-95 wt% tungsten powder, 3-6 wt% nickel-iron alloy and 0.5-1.0 wt% aluminum powder at 1400-1450℃ into the lower rectangular cavity placed upside down and covering the exposed part of the ceramic core, so that the W-Ni-Fe alloy melt forms an irregular interface with the unfrozen part of the basalt melt due to gravity and flow impact force;

[0011] S5, solidification and cooling, sequentially performing controlled cooling at 5-20℃ / min to 500-700℃ and air cooling, or directly water cooling to room temperature, to obtain the ceramic-alloy metallurgical bonded flywheel product.

[0012] In a preferred technical solution, in step S2, the components of the ceramic core include: basalt powder 70-85 wt%, γ-Al2O3 powder 5-10 wt%, TiO2 powder 1-3 wt%, Fe2O3 powder 0.5-1 wt%, Li2O-SiO2 glass micro powder 3-8 wt%, and Na2O-B2O3 low melting point binder 1-2 wt%.

[0013] In a preferred technical solution, the ceramic core is prepared according to the following steps:

[0014] S21, wet ball milling the raw materials under the condition of ball-to-material ratio 3:1-5:1 for 6-10 h to form a slurry;

[0015] S22, adding 1-2 wt% polyvinyl alcohol to the slurry and then spray granulating, inlet temperature 200-230℃, outlet temperature 80-95℃, to obtain granulated powder with average particle size 50-80 μm;

[0016] S23, cold isostatic pressing the granulated powder, pressure 150-250 MPa, time 60-120 s;

[0017] S24, pre-oxidizing the green body by heating to 600-700℃ and holding for 1-2 h;

[0018] S25, sintering the ceramic core by heating to 1350-1400℃ and holding for 2-4 h, and then heating to 1450-1480℃ and holding for 0.5-1 h.

[0019] In a preferred technical solution, the basalt melt composition satisfies SiO245-52wt%, Al2O312-18wt%, Fe2O36-10wt%, MgO4-7wt%, CaO5-9wt%, Na2O+K2O3-6wt%, and the balance is TiO2 and trace elements.

[0020] In a preferred technical solution, the tungsten powder in the W-Ni-Fe alloy melt has a particle size of 1-5µm, the mass ratio of Ni:Fe in the nickel-iron alloy is 2-3:1, and 0.01-0.05wt% boron is added during smelting to improve the interface wettability.

[0021] In a preferred technical solution, the time interval between step S3 and step S4 is controlled to be 30-120s to ensure that the basalt initial solidification shell is in a semi-solid semi-liquid state.

[0022] In a preferred technical solution, an axial pressure of 0.3-0.6MPa is applied to the mold for 60-180s after step S4 to reduce pores and improve density.

[0023] The application also provides a liquid-liquid composite ceramic-inlaid high-wear-resistance pendulum hammer, which is prepared according to the method and is composed of 30-60vol% basalt ceramic body and the balance of W-Ni-Fe alloy matrix metallurgically bonded together, and the density of the alloy matrix is not less than 17.0g / cm 3 .

[0024] In a preferred technical solution, the ceramic-alloy interface transition zone has a thickness of 5-50µm and contains continuously gradient-distributed (W,Fe)6SiB2 and (Zr,Ti)O x phases to release thermal stress.

[0025] In a preferred technical solution, the overall Rockwell hardness HRC of the pendulum hammer reaches 56-63, and the impact toughness a k (ISO) is greater than 18J / cm 2 .

[0026] The application also provides a pendulum hammer breaking device, which is equipped with the pendulum hammer and is suitable for high-load operation in the mining and metallurgical industries with single hammer impact energy ≥300J.

[0027] Beneficial effects:

[0028] The application adopts a split type double-cavity mold structure, wherein the upper end is a conical cavity, the lower end is a rectangular cavity, a stepped platform is arranged at the junction for embedding a ceramic core, and through preheating, vacuum pouring and two-step melt pouring, a composite structure of basalt initial solidification shell and high-density W-Ni-Fe alloy melt covering the exposed part of the ceramic core is formed, which is beneficial to form a continuous and dense transition interface and avoid the problems of interlayer gap and interface discontinuity.

[0029] In the preparation process of the ceramic core, basalt is used as the main body and multi-component oxides and glass phases are introduced, and through wet ball milling, spray granulation, cold isostatic pressing, pre-oxidation and two-stage temperature rising sintering process, a structural unit with a matching thermal expansion coefficient with the metal matrix, high sintering density and controllable surface state is obtained; boron element and specific Ni / Fe ratio are introduced in the alloy melt composition control, which further optimizes the alloy fluidity and interface wetting behavior.

[0030] The flywheel prepared by the method has ceramic parts uniformly arranged on the striking end face and forming structural protrusions, the alloy matrix is dense and complete, the interface bonding area has a continuous transition composite phase structure, the overall structure of the flywheel is stable, the mechanical properties are balanced, and the flywheel can be applied to various high-impact and high-load industrial environments, and meet the long-period and high-frequency operation requirements of mining and metallurgical industry equipment. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a schematic diagram of the flywheel structure of the application;

[0032] Figure 2 It is an SEM photo of the sample of the embodiment of the application; wherein (a) for the sample of the first embodiment, (b) for the sample of the second embodiment, (c) for the sample of the third embodiment;

[0033] Figure 3 It is a schematic diagram of the comparative experiment results (density) of the application;

[0034] Figure 4 It is a schematic diagram of the comparative experiment results (Rockwell hardness) of the application;

[0035] Figure 5 It is a schematic diagram of the comparative experiment results (impact toughness) of the application;

[0036] Figure 6 It is a schematic diagram of the comparative experiment results (wear weight loss) of the application;

[0037] Figure 7 It is a schematic diagram of the comparative experiment results (shear strength) of the application. DETAILED DESCRIPTION

[0038] In order to deepen the understanding of the present application, the present application will be further described below in conjunction with examples, which are only used to explain the present application and do not constitute a limitation to the protection scope of the present application.

[0039] Example one (T1)

[0040] The present embodiment provides a liquid-liquid composite ceramic inlay high-wear-resistance pendulum, which has a shape structure as shown in Figure 1 The preparation method comprises the following steps:

[0041] S1, mold preparation: a steel mold is selected, an upper end conical cavity and a lower end rectangular cavity are arranged inside, and a stepped platform with a width of 10 cm is formed at the junction of the two. The whole mold is preheated to 180℃ for standby.

[0042] S2, ceramic core installation: basalt-based ceramic cores are installed into the positioning grooves at the junction positions of the mold, the upper end of the ceramic cores is 10 cm higher than the stepped platform, and the embedding depth is maintained at 10 cm.

[0043] The raw material ratio of the ceramic core is: basalt powder 78wt%, γ-Al2O3 powder 8wt%, TiO2 powder 2wt%, Fe2O3 powder 1wt%, Li2O-SiO2 glass micro powder 8wt%, and Na2O-B2O3 low-melting-point binder 1wt%. Each raw material is wet ball milled for 8 hours under the condition of a ball-to-material ratio of 4:1 to obtain a stable slurry. After adding 1.5wt% polyvinyl alcohol, spray drying is carried out, the inlet temperature is 220℃, and the outlet temperature is 90℃, to obtain a granulated powder with an average particle size of 65μm.

[0044] The granulated powder is pressed in an isostatic pressing equipment for 90s under a pressure of 200MPa to obtain a green body with good density. Then, pre-oxidation treatment is carried out by heating to 650℃ for 1.5h, sintering is carried out by continuing to heat to 1380℃ for 3h and then heating to 1460℃ for 1h, to obtain a dense ceramic core, which has a thermal expansion coefficient compatible with the thermal expansion behavior of W-Ni-Fe alloy.

[0045] S3, first pouring: basalt block material with a chemical composition of SiO248wt%, Al2O316wt%, Fe2O37wt%, MgO6wt%, CaO7wt%, Na2O+K2O5wt%, and the rest being TiO2 and trace elements, is heated to 1480℃ in a quartz crucible to completely melt, and is injected into the upper end conical cavity under a vacuum condition of 0.08MPa to form a primary condensed basalt melt shell with a thickness of 6mm.

[0046] S4, Second Pouring: Within 80s after the first pouring is completed, a W-Ni-Fe alloy melt is prepared, with a ratio of 94wt% tungsten powder, 5wt% nickel-iron alloy (wherein Ni:Fe = 2.5:1), and 1wt% aluminum powder, wherein the tungsten powder has a particle size controlled at 3μm, and the smelting temperature is controlled at 1430℃. The melt is poured from the upside end of the mold to be placed upside down, so that the alloy melt flows and covers the exposed area of the ceramic core. Since the basalt initial solidification layer is in a semi-solid and semi-liquid state, the alloy melt forms a natural disturbance interface with the non-solidified part thereof.

[0047] S5, Solidification and Cooling: After the alloy melt is poured, an axial pressure of 0.5MPa is applied to the mold for 120s. Subsequently, it is cooled at a rate of 10℃ / min to 650℃, and naturally kept at this temperature for 40min, and finally naturally air-cooled to room temperature to obtain a ceramic-metal metallurgical bond.

[0048] Example Two (T2)

[0049] The embodiment provides a liquid-liquid composite ceramic-inlaid high-wear-resistance pendulum bob, and a preparation method thereof.

[0050] S1, Mold Preparation: A composite steel mold is used, which comprises a tapered cavity at the upper end and a rectangular cavity at the lower end, and a stepped platform with a width of 10cm is formed at the junction of the cavities. The mold is preheated to 210℃ in a constant temperature furnace.

[0051] S2, Ceramic Core Installation: The ceramic core is installed into the positioning groove, so that the top of the ceramic core is about 10.0cm higher than the opening of the mold, and the embedding depth is about 10.0cm.

[0052] The ceramic core comprises basalt powder 82wt%, γ-Al2O3 powder 6wt%, TiO2 powder 1wt%, Fe2O3 powder 0.8wt%, Li2O-SiO2 glass micropowder 8wt%, and Na2O-B2O3 binder 2wt%. The raw materials are ball milled in a ball-to-material ratio of 4:1 for 10h to form a stable dispersion slurry. After 1wt% polyvinyl alcohol is added, spray drying is performed at an inlet temperature of 210℃ and an outlet temperature of 85℃ to obtain granulated powder with an average particle size of about 72μm.

[0053] The powder is formed by cold isostatic pressing at a pressure of 180MPa for 90s. The green body is heated to 620℃ for 2h for pre-oxidation, then heated to 1350℃ at a rate of 5℃ / min for 3h, and then heated to 1450℃ for 0.5h for sintering.

[0054] S3, First pouring: basalt material with the mass composition of SiO2 50wt%, Al2O3 15wt%, Fe2O3 6wt%, MgO 5wt%, CaO 8wt%, Na2O+K2O 4wt%, and the rest of TiO2 and impurities, is melted and degassed at 1450℃. The melt is poured into the upper end cavity under the vacuum condition of 0.07 MPa to form a primary solidified basalt shell layer.

[0055] S4, Second pouring: within about 50s after the first pouring is completed, W-Ni-Fe alloy melt is poured into the lower end rectangular cavity. The alloy ratio is: tungsten powder 95wt%, nickel-iron alloy 4wt% (wherein Ni:Fe=3:1), aluminum powder 1wt%, the particle size of tungsten powder is 1μm, and the smelting temperature is 1405℃. After the melt covers the exposed surface of the ceramic core, it flows naturally to form an embedded interface with the basalt primary solidified layer which is still in a viscous plastic state.

[0056] S5, Solidification and cooling: an axial pressure of 0.4 MPa is applied to the mold for 90s, and then cooled to 600℃ at a rate of 15℃ / min, and kept at this temperature for 30min, and finally cooled to room temperature by water.

[0057] Example Three (T3)

[0058] The embodiment provides a liquid-liquid composite ceramic inlay high-wear-resistance pendulum bob, and a preparation method thereof.

[0059] S1, Mould preparation: an alloy steel mould is used, which contains an upper end conical cavity and a lower end rectangular cavity, and a stepped platform with a width of 10cm is processed at the junction. The mould is placed in a hot air circulation furnace and preheated to 195℃.

[0060] S2, Ceramic core installation: a prefabricated ceramic core is embedded in the positioning groove, and the top of the ceramic core is 10cm higher than the opening of the mould, and the embedding depth is 10cm.

[0061] The ceramic core formula (mass percentage) is: basalt powder 80%, γ-Al2O3 7%, TiO2 2%, Fe2O3 0.8%, Li2O-SiO2 glass powder 8%, and Na2O-B2O3 binder 1.2%.

[0062] Wet ball milling conditions: ball-to-material ratio 4:1, time 8h;

[0063] Spray granulation: 1.5wt% PVA is added, the inlet temperature is 215℃, the outlet temperature is 88℃, and the average particle size is about 65μm;

[0064] Cold isostatic pressing: 200MPa x 90s;

[0065] Pre-oxidation: 650℃ x 1.5h;

[0066] Sintering: 1370 °C x 3 h, then up to 1470 °C x 0.7 h.

[0067] S3, First pouring: basalt melt with components of SiO2 49 wt%, Al2O3 15 wt%, Fe2O3 7 wt%, MgO 5 wt%, CaO 7 wt%, Na2O+K2O 4 wt%, and the balance of TiO2 was prepared, and after complete melting at 1475 °C, it was poured into the upper cavity under a vacuum condition of 0.075 MPa to form a 6 mm thick initial solidification shell.

[0068] S4, Second pouring: 75 s after the first pouring was completed, a W-Ni-Fe alloy melt was prepared: tungsten powder 94 wt% (particle size ≈ 3 µm), nickel-iron alloy 5 wt% (Ni:Fe = 2.5:1), aluminum powder 1 wt%, and 0.03 wt% boron element was added; the smelting temperature was 1420 °C. The melt was poured from the lower end and covered the exposed surface of the ceramic core, forming a corrugated transition interface with the basalt layer in a viscous plastic state.

[0069] S5, Solidification and cooling: an axial pressure of 0.45 MPa was applied to the mold for 120 s. Then it was cooled at a rate of 12 °C / min to 630 °C and held for 35 min, and finally naturally air-cooled to room temperature.

[0070] Comparative Example One (C1)

[0071] This comparative example changed the composition of the ceramic core based on the same mold structure and pouring process, and no longer used the multi-phase synergistic optimization design to verify the changes in interface matching and overall product performance.

[0072] S1, Mold preparation: a metal mold with the same structure as Example One was used, and the width of the stepped platform at the junction was 10 cm. The entire mold was preheated to 180 °C.

[0073] S2, Ceramic core installation: a single component ceramic core material was used, which was embedded into the positioning groove and made the upper end 10 cm higher than the mold. The ceramic core composition (mass percentage): basalt powder 98%, polyvinyl alcohol 2%; no γ-Al2O3, TiO2, Fe2O3, glass phase, etc. regulating components were added.

[0074] Wet ball milling for 6 h, after spray drying the particle size distribution was uneven, and the average particle size was close to 90 µm;

[0075] The molding pressure was 180 MPa, the sintering temperature was 1300 °C, and the holding time was 2 h, and the final density was significantly lower than that of the example.

[0076] The measured value of the coefficient of thermal expansion was much higher than that of the W-Ni-Fe alloy, and the interface thermal stress was difficult to relieve.

[0077] S3, First pouring: Basalt melt composition is the same as the example, poured at 1480 °C under vacuum, forming a 6 mm as-cast shell.

[0078] S4, Second pouring: W-Ni-Fe alloy melt (94 wt% W, 5 wt% NiFe, 1 wt% Al) is prepared at a temperature of 1430 °C and poured into the mold 70 s after the first pouring, forming a metal clad structure.

[0079] S5, Solidification and cooling: The mold cooling process uses the same process conditions as the example, with an axial pressure of 0.5 MPa and a controlled cooling rate of 10 °C / min to 620 °C, followed by air cooling.

[0080] Comparative Example Two (C2)

[0081] This comparative example is based on Example Three (T3), with only key changes in the pouring sequence and subsequent solidification parameters, to verify the influence of the "first and second pouring time interval" and "compaction treatment" on the interface quality.

[0082] S1, Mold preparation: The mold used is the same size and material as T3, with a stepped platform width of 20 cm and a height difference of 7 mm. The mold is preheated to 195 °C.

[0083] S2, Ceramic core installation: The ceramic core formulation remains consistent with T3 (basalt 80 wt%, γ-Al2O3 7 wt%, TiO2 2 wt%, Fe2O3 0.8 wt%, Li2O-SiO2 8 wt%, Na2O-B2O3 1.2 wt%). The preparation and installation process is the same as T3.

[0084] S3, First pouring: Basalt melt composition, melting temperature (1475 °C), and vacuum conditions (0.075 MPa) are the same as T3, forming a 6 mm as-cast shell.

[0085] S4, Second pouring: Time interval: extended to 180 s (T3 is 75 s), allowing the basalt shell to almost completely solidify.

[0086] Alloy melt: Maintaining the T3 ratio (94 wt% W / 5 wt% NiFe / 1 wt% Al, containing 0.03 wt% B), temperature 1420 °C. No axial pressure is applied, only natural solidification.

[0087] S5, Solidification and cooling: Cooling rate, holding temperature, and air cooling process are the same as T3.

[0088] Comparative Example Three (C3)

[0089] The comparative example adopts a common integral type flywheel preparation process in the prior art, the material is wear-resistant high chromium cast iron, the flywheel is prepared by single melt pouring, there is no ceramic insert and no two-phase interface design, and the specific steps are as follows:

[0090] S1, mold preparation: an integral sand mold is used, the size is similar to that of the mold of the application, the inside is a standard rectangular cavity structure, the mold is not provided with a stepped platform structure, and the preheating temperature is controlled at 120℃.

[0091] S2, material preparation: high chromium cast iron alloy is selected, the main components of which are: Cr 26wt%, C 2.5wt%, Si 0.6wt%, Mn 0.5wt%, Mo 1.2wt%, Ni 0.5wt%, and the rest is Fe. All alloying elements are melted in a medium-frequency induction furnace, and the melting temperature is 1450℃.

[0092] S3, pouring forming: the high chromium cast iron melt after melting is directly injected into the mold cavity, a gravity pouring mode is adopted, and no multi-step or multi-zone temperature control is set; after pouring, it is naturally cooled to room temperature under room temperature conditions, and the cooling time is about 6 hours.

[0093] S4, post-processing procedure: after the cooling of the casting is completed, polishing, edge cutting, and removal of the gating system are performed, and the integral flywheel is quenched (980℃, 3h) and tempered (250℃, 2h) to improve the performance of the matrix structure.

[0094] Comparative example four (C4)

[0095] The comparative example adopts a double-metal composite flywheel preparation method commonly used in traditional industry, and a composite structure is formed by inner and outer cladding type metal casting, and the specific steps are as follows:

[0096] S1, mold preparation: a composite sand mold with an insert structure is used, and the outer size is consistent with that of example three. The mold cavity is divided into an upper composite area and a lower support area, the mold is not provided with a ceramic slot, only a metal core support positioning structure is provided, and the mold preheating temperature is controlled at 130℃.

[0097] S2, core preparation: a low alloy steel piece is selected as a force-bearing core block, and the composition is: C 0.35wt%, Mn 0.8wt%, Si 0.5wt%, Cr 0.5wt%, Ni 0.3wt%, and the rest is Fe; the core block is machined to have a surface roughness of Ra12μm, and is embedded into the lower part of the mold as a base.

[0098] S3, alloy melting and pouring: high chromium cast iron alloy is melted, and the composition is: Cr 24wt%, C 2.3wt%, Mo 1.0wt%, Mn 0.6wt%, Si 0.7wt%, and the rest is Fe. The melting temperature is 1430℃.

[0099] The molten high-chromium iron alloy is directly injected into the upper cavity of the mold, the alloy melt is wrapped on the surface of the low alloy steel core to form an integral flywheel; the pouring mode is gravity pouring, and the flywheel is cooled in air for 8 hours after pouring.

[0100] S4, heat treatment process: after casting, the integral flywheel is subjected to quenching and tempering treatment: quenching temperature 960 DEG C, holding for 2h, oil cooling; tempering temperature 280 DEG C, holding for 1.5h, air cooling to room temperature.

[0101] Comparative experiment

[0102] The purpose of the experiment is to compare the effects of different structures, materials and processes on the performance of the flywheel by uniformly testing the physical properties, interface morphology and service life simulation of the flywheel samples prepared in examples T1, T2 and T3 and comparative examples C1, C2, C3 and C4, and verifying the technical advantages of the liquid-liquid composite ceramic inlay structure in wear resistance, impact toughness and interface stability, as shown in Table 1:

[0103] Table 1: Grouping of comparative experiment

[0104]

[0105] Test items and methods

[0106] 1. Scanning electron microscope (SEM) observation:

[0107] The ceramic-alloy interface region is selected and cut into a cross-section sample of about 10mmx10mmx5mm, and then ground to a mirror effect by metallographic sandpaper and polishing agent in turn. The sample surface is cleaned by ultrasonic wave and then sprayed with conductive gold. The scanning electron microscope is used to observe under the conditions of acceleration voltage 15kV and working distance about 10mm.

[0108] Technical target: observe the bonding between basalt ceramic component and W-Ni-Fe alloy.

[0109] 2. Density test (Archimedes method):

[0110] Equipment: electronic density analysis balance (accuracy 0.001g);

[0111] Test method: use deionized water as the immersion liquid, and weigh the dry weight and the weight in the immersion liquid respectively; test 3 samples in each group, and calculate the average density (g / cm 3 );

[0112] Technical target: judge the density and material uniformity of the finished product, and indirectly reflect the forming and sintering effect.

[0113] 3. Hardness test (Rockwell hardness HRC):

[0114] Instrument: Rockwell hardness tester;

[0115] Test method: Test the ceramic part and metal substrate of the hammer striking surface separately; take 5 different points for testing in each area and record the average value;

[0116] Technical goal: To compare the surface hardness differences under different materials and process conditions.

[0117] 4. Impact toughness test (Charpy U-notch):

[0118] Specimen size: 10mm×10mm×55mm, center U-shaped notch 2mm deep;

[0119] Instrument: Impact testing machine (300J class, equipped with photoelectric reading system);

[0120] Quantity: Each group of tests should be no less than 3 pieces, and the average absorbed energy should be recorded. Value (J / cm 2 );

[0121] Technical goal: To reflect the fracture resistance of materials under impact loads and evaluate interface strength matching.

[0122] 5. Wear performance test:

[0123] Test conditions: Loading pressure: 5 kg; Contact speed: 200 r / min; Total revolutions: 1000 rpm; Sand particle size: 300-500 μm; Measurement data: Weigh before and after the test, and record weight loss (mg); Repeatability: 3 specimens per group, average value taken.

[0124] Technical goal: Wear rate (mg / min) reflects wear resistance.

[0125] 6. Interface shear strength test:

[0126] Sample preparation: Cubic specimens with dimensions of 10 mm × 10 mm × 10 mm were cut along the ceramic-alloy interface. Testing equipment: Universal electronic tensile testing machine (Instron 3365); Loading speed: 1 mm / min.

[0127] Measurement indicators: record shear failure load (N); calculate shear strength: σ=F / A (MPa);

[0128] Technical goal: To evaluate the binding ability under different interface structures.

[0129] The experimental data are shown in Table 2:

[0130] Table 2 Comparative experimental data

[0131]

[0132] Data analysis:

[0133] The experiment compared and analyzed the differences in a number of key performance indicators between examples T1, T2, T3 and comparative examples C1, C2, C3 and C4, and the test contents included SEM observation, density, hardness, impact toughness, wear performance and interface shear strength.

[0134] In Figure 2 , (a) represents the SEM photo of the example one sample, (b) represents the SEM photo of the example two sample, and (c) represents the SEM photo of the example three sample, it can be seen that there is sufficient fusion between the basalt melt and the W-Ni-Fe alloy, forming an irregular interface with good occlusion effect, and there are ceramic particles (black arrow) precipitated in the basalt melt, which are integrated into the W-Ni-Fe alloy, which can further improve the wear resistance of the impact tester product.

[0135] In the density test, as shown in Figure 3 , the average densities of examples T1, T2 and T3 are 13.1 g / cm 3 , 12.8 g / cm 3 and 12.9 g / cm 3 , respectively, which are significantly higher than those of comparative examples C1 (11.4 g / cm 3 ) and C2 (11.0 g / cm 3 ). This shows that under the conditions of alloy melt fluidity, ceramic core size matching and optimized controlled cooling system, the density of the composite can be effectively improved. The densities of C3 and C4, which represent the prior art solutions, are 9.2 g / cm 3 and 11.9 g / cm 3 , respectively, which have obvious deficiencies, reflecting the limitations of single material or split casting structure in overall forming.

[0136] In terms of hardness, as shown in Figure 4 , the HRC value of the ceramic part of T1 is 78.6, and the alloy substrate is 61.3, T2 and T3 also show a close level, while the hardness of the ceramic part of C1 and C2 is reduced to 72.4 and 70.1 respectively, and the substrate hardness is also lower than 60HRC, which shows that the adjustment of ceramic formula and alloy composition can effectively improve the organization density and microstructure stability. The overall hardness distribution of C3 and C4 is relatively uneven, and the local value is low.

[0137] In the impact toughness test, as shown in Figure 5 , the absorbed energy of T1 and T2 is 19.6 J / cm 2 and 18.2 J / cm 2 , respectively, which is much higher than that of C1 (13.5 J / cm 2) and C2 (12.0 J / cm 2 ). T3 is slightly lower (17.9 J / cm 2 ), but remains in a good range. It can be seen that the ceramic core height control, melt interaction time and interface processing method directly affect the stability of the composite zone under dynamic load. C3 and C4 are significantly deteriorated due to single material composition or lack of interface structure, with a toughness of only 10.6 J / cm 2 and 11.4 J / cm 2 , respectively.

[0138] In terms of wear performance, as shown in Figure 6 , the average weight loss of T1 group is 6.4 mg, and T2 and T3 are 7.0 mg and 6.7 mg, respectively, which are significantly better than C1 (10.3 mg) and C2 (11.6 mg). This trend shows that the good synergistic matching between the ceramic part and the alloy substrate and the structure of the metallurgical transition zone have a positive effect on the wear resistance under abrasive erosion. While C3 and C4 have higher wear values due to defects in the material body or interface, reaching 13.9 mg and 9.8 mg, respectively, which is difficult to meet the needs of continuous heavy load working conditions.

[0139] In terms of interface shear strength, as shown in Figure 7 , the T1 group sample shows the best performance, with an average shear strength of 42.3 MPa, T2 and T3 are 39.7 MPa and 40.1 MPa, respectively, C1 and C2 are significantly lower, only 28.6 MPa and 26.2 MPa, reflecting that they failed to form effective physical engagement and chemical wetting in the alloy impact pouring and ceramic initial setting state. C3 and C4 have different process paths, with interface shear strengths of 19.4 MPa and 23.6 MPa, respectively, showing typical weak interface characteristics of non-metallurgical bonding.

[0140] In summary, examples T1-T3 are superior to the comparative examples and prior art in multiple performance indicators, verifying the effectiveness of the liquid-liquid composite pouring path, ceramic core compound system and interface process parameters proposed by the present application in improving overall performance. Especially in achieving the comprehensive performance goals of high density, strong interface bonding and high wear resistance, it shows strong technical advantages and application prospects.

[0141] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a liquid-liquid composite ceramic inlaid high wear-resistant hammer, characterized in that: The following steps are involved: S1. Mold preparation: preheating a metal mold to 150-250°C; the metal mold has an upper conical cavity and a lower rectangular cavity, and a stepped surface with a width of 10-20 cm at the junction of the upper conical cavity and the lower rectangular cavity; S2. Install the ceramic core: insert the ceramic core into the junction and make the top 2.0-10.0 cm higher than the notch. The ceramic core comprises: 70-85 wt % basalt powder, 5-10 wt % γ-Al2O3 powder, 1-3 wt % TiO2 powder, 0.5-1 wt % Fe2O3 powder, 3-8 wt % Li2O-SiO2 glass powder, and 1-2 wt % Na2O-B2O3 low-melting-point binder. The composition of basalt melt meets the following requirements: SiO2 45-52 wt%, Al2O3 12-18 wt%, Fe2O3 6-10 wt%, MgO 4-7wt%, CaO 5-9 wt%, Na2O+K2O 3-6 wt%, and the balance is TiO2 and trace elements; Prepared by following the steps below: S21, wet-milling the raw materials at a ball-to-material ratio of 3:1-5:1 for 6-10 h to form a slurry; S22, adding 1-2 wt% polyvinyl alcohol to the slurry and spray granulating it at an inlet temperature of 200-230°C and an outlet temperature of 80-95°C to obtain granulated powder with an average particle size of 50-80 μm; S23, cold isostatic pressing the granulated powder at a pressure of 150-250 MPa for 60-120 s; S24, heating the green body to 600-700°C and keeping the temperature for 1-2 hours for pre-oxidation; S25, maintaining the temperature at 1350-1400 °C for 2-4 h, then increasing the temperature to 1450-1480 °C and maintaining the temperature for 0.5-1 h to obtain a ceramic core; S3, first pouring, pouring 1450-1500 °C basalt melt into the inverted upper conical cavity under a vacuum degree of 0.06-0.09 MPa until a primary solidified shell with a thickness of 2-10 mm is formed; S4, a second pouring, wherein the time interval between step S3 and step S4 is controlled to be 30-120 s to ensure that the primary basalt shell is in a semi-solid and semi-liquid state, and a W-Ni-Fe alloy melt obtained by smelting 93-95 wt% tungsten powder, 3-6 wt% nickel-iron alloy, and 0.5-1.0 wt% aluminum powder at 1400-1450° C. is poured into the inverted lower rectangular cavity and covers the exposed portion of the ceramic core, so that the W-Ni-Fe alloy melt forms an irregular interface with the unsolidified portion of the basalt melt due to gravity and flow impact; S5, solidification cooling, sequentially performing controlled cooling at 5-20°C / min to 500°C and air cooling to room temperature to obtain a ceramic-alloy metallurgical bonded hammer product.

2. The method for preparing a liquid-liquid composite ceramic inlaid high wear-resistant hammer according to claim 1, characterized in that: The particle size of tungsten powder in the W-Ni-Fe alloy melt is 1-5 µm, the mass ratio of Ni:Fe in the nickel-iron alloy is 2-3:1, and 0.01-0.05 wt% boron is added during the smelting process to improve the interface wettability.

3. The method for preparing a liquid-liquid composite ceramic inlaid high wear-resistant hammer according to claim 2, characterized in that: After step S4, an axial pressure of 0.3-0.6 MPa is applied to the mold and maintained for 60-180 seconds.

4. A liquid-liquid composite ceramic inlaid high wear-resistant hammer, prepared by the method according to any one of claims 1 to 3, characterized in that: The hammer is metallurgically bonded by a 30-60 vol% basalt ceramic body and a W-Ni-Fe alloy matrix with a density of not less than 17.0 g / cm³.

5. The swing hammer according to claim 4, characterized in that: The thickness of the ceramic-alloy interface transition zone is 5-50 μm and contains a continuous gradient distribution of (W,Fe)6SiB2 and (Zr,Ti)O x phase to relieve thermal stress.

6. The swing hammer according to claim 5, characterized in that: The overall Rockwell hardness of the hammer reaches HRC 56-63, and the impact toughness is a k (ISO) greater than 18 J / cm².

7. A swing hammer crushing device, characterized in that: The equipment is equipped with the swing hammer described in any one of claims 4 to 6 and is suitable for high-load operations in the mining and metallurgical industries where the single hammer impact energy is ≥300 J.

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