Composite material for grate plate of chain grate machine and preparation method of composite material

Abstract

The invention discloses a chain grate plate composite material and a preparation method thereof, and relates to the technical field of high-temperature corrosion-resistant materials, the chain grate plate composite material comprises a heat-resistant stainless steel component and a coating component, the heat-resistant stainless steel component comprises austenitic steel containing nitrogen and niobium, the coating component is an iron-aluminum alloy, and the iron-aluminum alloy contains niobium carbide particles. According to the chain grate plate composite material, a Fe3Al alloy coating is generated on high-carbon austenitic steel containing nitrogen and niobium, the surface hardness is greatly improved, and meanwhile the volume wear rate, the high-temperature oxidation corrosion rate and the high-temperature salt corrosion rate are greatly reduced; after the composite material is subjected to 100 times of cyclic thermal shock, cracks and spalling in any form do not occur on the coating, and the bonding interface of the coating and a matrix is good.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature corrosion-resistant materials, and in particular to a chain grate grate plate composite material and a preparation method thereof. Background Art

[0002] The grate is a core component of the chain grate in the pelletizing chain-return-loop system. Hot air from the rotary kiln and ring cooler reaches temperatures of up to approximately 1000°C when reaching the grate. Since the grate supports the pellets, a thick layer of pellet material weakens heat transfer, resulting in a surface temperature of around 800°C. Therefore, grate material must withstand long-term service at temperatures around 800°C, making oxidation resistance a primary requirement. Furthermore, some pellets contain high sulfur (~0.5%). During prolonged high-temperature operation, sulfur reacts with elements such as sodium, potassium, and chloride in the pellets or the auxiliary bentonite, forming sulfates and chlorides that adhere to the grate surface, causing salt corrosion and shortening the grate's service life. Therefore, in addition to high-temperature oxidation resistance, grate material also requires excellent resistance to salt corrosion, particularly sulfur and chlorine corrosion. Austenitic stainless steel with high Cr and high Ni content has excellent oxidation resistance and is mostly used for high-temperature heat-resistant parts. However, its ability to resist high-temperature sulfur and chlorine corrosion is weak, and it also has disadvantages such as low hardness and poor wear resistance.

[0003] Fe3Al is an intermetallic compound with high hardness. During daily service, an Al2O3 oxide layer forms on its surface to protect it. Without the addition of scarce metals such as Cr, Ni, and Co, it maintains excellent resistance to high-temperature oxidation and corrosion, making it ideal for use as a working component in corrosive environments. These two properties are particularly significant when the operating temperature is below 1000°C. However, Fe3Al bulk material has poor casting properties, making it difficult to mass-produce grate plate parts with certain dimensional accuracy requirements. Furthermore, due to the intrinsic properties of its intermetallic compound, the bulk material is prone to cracking and failure under external forces.

[0004] Therefore, it is difficult for current grate plate materials to have both high-temperature oxidation resistance and high-temperature corrosion resistance, and there is also the problem of being difficult to produce in large quantities. Summary of the Invention

[0005] Based on the problem that current grate plate materials are difficult to achieve both high-temperature oxidation resistance and high-temperature corrosion resistance and are difficult to prepare in large quantities, the purpose of the present invention is to provide a chain grate plate composite material and a preparation method thereof, and an in-situ laser cladding technology is used to generate an Fe3Al alloy coating on high-carbon austenitic steel containing nitrogen and niobium. While the surface hardness is greatly improved, the volume wear rate, high-temperature oxidation corrosion rate and high-temperature salt corrosion rate are greatly reduced.

[0006] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a chain grate plate composite material, comprising a heat-resistant stainless steel component and a coating component, wherein the heat-resistant stainless steel component comprises austenitic steel containing nitrogen and niobium elements, and the coating component is an iron-aluminum alloy containing niobium carbide particles.

[0007] The niobium element in the austenitic steel of the present invention can preferentially generate NbC carbides, thereby inhibiting Cr from carburizing chromium (Cr 23 Niobium carbide precipitates in the form of chromium (C6), preventing the chromium content of the austenite near the grain boundaries from falling below the minimum level for stainless steel corrosion resistance, thereby concentrating corrosion in the chromium-depleted regions of the grain boundaries. Nitrogen increases the stability of austenitic steel and reduces nickel content, thereby reducing costs. Niobium acts as an interstitial element in the austenite lattice, thereby increasing the hardness and strength of the material and improving its wear resistance. Niobium carbide exhibits high hardness and a high melting point. Niobium is a strong carbide former and precipitation hardener, providing excellent strength, impact resistance, corrosion resistance, and weldability at high temperatures. An iron-aluminum alloy coating containing niobium carbide particles was fabricated on austenitic steel containing nitrogen and niobium. The hardness of the composite material was significantly increased while the volume wear rate, high-temperature oxidative corrosion rate, and high-temperature salt corrosion rate were significantly reduced. Experimental results confirmed that the composite material exhibited no cracking or flaking after 100 cycles of thermal shock, demonstrating a good interface between the coating and the substrate.

[0008] Furthermore, the heat-resistant stainless steel composition also includes chromium, nickel, niobium, molybdenum, silicon, manganese, carbon, nitrogen, phosphorus and sulfur.

[0009] Furthermore, the mass percentages of the elements in the heat-resistant stainless steel component are: 23% to 25% chromium, 9% to 10% nickel, 0.3% to 0.5% niobium, 2% to 3% molybdenum, 1% to 2% silicon, 1% to 2% manganese, 0.3% to 0.4% carbon, 0.4% to 0.6% nitrogen, phosphorus <0.03%, sulfur <0.03%, and the balance is iron.

[0010] Furthermore, the mass percentage of aluminum element in the iron-aluminum alloy is 13% to 20%, and the balance is iron.

[0011] In a second aspect, the present application provides a method for preparing a chain grate plate composite material, wherein iron-aluminum pre-alloyed powder is clad on austenitic steel containing nitrogen and niobium elements by laser cladding to form a coating on the austenitic steel to form a composite material.

[0012] In-situ laser cladding technology is used to generate Fe3Al alloy coating on high-carbon austenitic steel containing nitrogen and niobium elements. The surface hardness is greatly improved while the volume wear rate, high-temperature oxidation corrosion rate and high-temperature salt corrosion rate are greatly reduced.

[0013] Furthermore, the particle size of the iron-aluminum pre-alloyed powder is 80 μm to 150 μm.

[0014] If the powder particle size is too small, it will be easily blown away by the cladding airflow, resulting in loss; if the particle size is too large, it will be detrimental to the densification of the coating and its close bonding with the substrate.

[0015] Furthermore, the thickness of the coating is 0.5 mm to 1.5 mm.

[0016] Furthermore, when the coating is prepared by laser cladding, the laser power is controlled at 700W~1500W, the laser scanning speed is controlled at 3mm / s~10mm / s, the laser spot diameter is 2mm~3mm, and the defocus amount is +2mm~+10mm.

[0017] Furthermore, laser cladding is performed under an inert gas, wherein the inert gas is argon.

[0018] Furthermore, the flow rate of the protective argon gas is controlled at 10 L / min~15 L / min; the flow rate of the powder feeding argon gas is controlled at 5 L / min~9 L / min, and the powder feeding rate is 8 g / min~20 g / min.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The chain grate plate composite material of the present invention forms an Fe3Al alloy coating on high-carbon austenitic steel containing nitrogen and niobium elements, significantly improving the surface hardness while significantly reducing the volume wear rate, high-temperature oxidation corrosion rate, and high-temperature salt corrosion rate. After 100 cycles of thermal shock, the coating of the composite material did not crack or peel off in any form, and the bonding interface between the coating and the substrate was good.

[0020] (2) The present invention uses high carbon austenitic steel containing niobium elements, which can preferentially generate NbC carbides, thereby inhibiting Cr from carburizing chromium (Cr 23 C6) to prevent the chromium content of austenite near the grain boundary from dropping below the minimum corrosion resistance of stainless steel, thereby concentrating the corrosion in the chromium-poor area at the grain boundary; nitrogen can increase the stability of austenite and reduce the nickel content, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in this application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a scanning electron microscope (SEM) image of the coating sample interface after 10 thermal shocks in Example 1 of the present invention; Figure 2 This is a scanning electron microscope (SEM) image of the coating sample interface after 50 thermal shocks in Example 1 of the present invention; Figure 3 This is a scanning electron microscope (SEM) image of the interface of the coating sample of Example 1 of the present invention after 100 thermal shocks; Figure 4 This is a high-temperature oxidation morphology diagram of the base stainless steel of Example 1 of the present invention; Figure 5 This is a graph showing the high-temperature oxidation corrosion rate per unit area of ​​the base stainless steel of Example 1 of the present invention; Figure 6 This is a high temperature oxidation morphology of Fe3Al according to Example 1 of the present invention; Figure 7 This is a graph showing the high-temperature oxidation corrosion rate per unit area of ​​Fe3Al in Example 1 of the present invention; Figure 8 This is a high-temperature salt corrosion morphology of the base stainless steel of Example 1 of the present invention; Figure 9 This is a graph showing the high-temperature salt corrosion rate per unit area of ​​the base stainless steel of Example 1 of the present invention; Figure 10 This is a high-temperature salt corrosion morphology of Fe3Al according to Example 1 of the present invention; Figure 11 This is the curve of high temperature salt corrosion rate per unit area of ​​Fe3Al; Figure 12 This is a high-temperature oxidation morphology of 310S stainless steel of Comparative Example 12; Figure 13 This is a graph showing the high-temperature oxidation corrosion rate per unit area of ​​310S stainless steel in Comparative Example 12; Figure 14 This is a high temperature salt corrosion morphology of 310S stainless steel in comparative example 12; Figure 15 This is a curve of the high-temperature salt corrosion rate per unit area of ​​310S stainless steel in comparative example 12. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples. The illustrative embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0024] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that these specific details are not necessarily employed to practice the present invention. In other embodiments, well-known materials or methods are not specifically described to avoid obscuring the present invention.

[0025] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment," "an embodiment," "an example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combinations and / or subcombinations. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, one skilled in the art will be able to combine and combine different embodiments or examples, and features of different embodiments or examples, described in this specification, without mutual inconsistency.

[0026] The "ranges" disclosed herein are defined in terms of lower and upper limits, where a given range is defined by selecting a lower limit and an upper limit, and the selected lower and upper limits define the boundaries of the particular range. Ranges defined in this manner can be inclusive or exclusive of the end values ​​and can be combined arbitrarily, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise indicated, the numerical range "a to b" is a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0027] Example 1 This embodiment provides a method for preparing a chain grate plate composite material, specifically: iron-aluminum pre-alloyed powder is clad on high-carbon austenitic steel containing nitrogen and niobium by laser cladding, forming a Fe3Al coating with a thickness of 0.5 mm on the austenitic steel to form a composite material.

[0028] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0029] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0030] Example 2 This embodiment provides a method for preparing a composite material for a chain grate plate. Unlike Example 1, the Fe3Al coating in this embodiment is 1.0 mm thick. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 1.0 mm thick Fe3Al coating on the austenitic steel, thereby forming a composite material.

[0031] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0032] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 12L / min, powder feeding argon gas flow rate 7L / min, powder feeding rate 12g / min, laser power 1400W, scanning speed 8mm / s, spot diameter 2.5mm, and defocus amount +3mm.

[0033] Example 3 This embodiment provides a method for preparing a composite material for a chain grate plate. Unlike Example 1, the Fe3Al coating in this embodiment is 1.5 mm thick. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 1.5 mm thick Fe3Al coating on the austenitic steel, thereby forming a composite material.

[0034] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0035] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 15L / min, powder feeding argon gas flow rate 9L / min, laser power 1500W, scanning speed 5mm / s, spot diameter 3mm, and defocus amount +8mm.

[0036] Example 4 This embodiment provides a method for preparing a composite material for a chain grate plate. Unlike Example 1, the mass percentage of niobium in this embodiment is 0.4%. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming the composite material.

[0037] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.4% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0038] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0039] Example 5 This embodiment provides a method for preparing a composite material for a chain grate plate. Unlike Example 1, the mass percentage of niobium in this embodiment is 0.5%. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming the composite material.

[0040] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.5% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0041] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0042] Example 6 This embodiment provides a method for preparing a composite material for a chain grate plate. Unlike Example 1, the mass percentage of nitrogen in this embodiment is 0.5%. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming the composite material.

[0043] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.5% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0044] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0045] Example 7 This embodiment provides a method for preparing a composite material for a chain grate plate. Unlike Example 1, the mass percentage of nitrogen in this embodiment is 0.6%. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming the composite material.

[0046] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.6% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0047] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0048] Example 8 This example provides a method for preparing a composite material for a chain grate. Unlike Example 1, the mass percentage of aluminum in the iron-aluminum alloy in this example is 15%. Specifically, the composite material is formed by laser cladding an iron-aluminum pre-alloyed powder onto high-carbon austenitic steel containing nitrogen and niobium, forming a 0.5 mm thick Fe3Al coating on the austenitic steel.

[0049] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 15% Al and the balance is iron, with a particle size of 80 μm.

[0050] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0051] Example 9 This example provides a method for preparing a composite material for a chain grate. Unlike Example 1, the mass percentage of aluminum in the iron-aluminum alloy in this example is 20%. Specifically, the method comprises laser cladding an iron-aluminum pre-alloyed powder onto high-carbon austenitic steel containing nitrogen and niobium, forming a 0.5 mm thick Fe3Al coating on the austenitic steel to form the composite material.

[0052] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 20% Al and the balance is iron, with a particle size of 80 μm.

[0053] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0054] Example 10 This embodiment provides a method for preparing a composite material for a chain grate. Unlike Example 1, the particle size of the iron-aluminum pre-alloyed powder in this embodiment is 100 μm. Specifically, the iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium, forming a 0.5 mm thick Fe3Al coating on the austenitic steel to form the composite material.

[0055] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 100 μm.

[0056] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0057] Example 11 This embodiment provides a method for preparing a chain grate plate composite material. Unlike Example 1, the particle size of the iron-aluminum pre-alloyed powder in this embodiment is 150 μm. Specifically, the iron-aluminum pre-alloyed powder is laser clad onto high-carbon austenitic steel containing nitrogen and niobium, forming a 0.5 mm thick Fe3Al coating on the austenitic steel to form the composite material.

[0058] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 150 μm.

[0059] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0060] Comparative Example 1 This comparative example provides a method for preparing a composite material for a chain grate. Unlike Example 1, this comparative example uses high-chromium, high-nickel 310S stainless steel as the substrate (chemical composition: 24.6% Cr, 19.5% Ni, 1.28% Mn, 0.42% Si, 0.08% C, 0.02% P, 0.02% S, balance Fe). Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto the high-chromium, high-nickel 310S stainless steel to form a 0.5 mm thick Fe3Al coating on the high-chromium, high-nickel 310S stainless steel, thereby forming the composite material.

[0061] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0062] Comparative Example 2 This comparative example provides a method for preparing a composite material for a chain grate. Unlike Example 1, the iron-aluminum alloy coating in this comparative example does not contain niobium carbide particles. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming a composite material.

[0063] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0064] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0065] Comparative Example 3 This comparative example provides a method for preparing a composite material for a chain grate plate. Unlike Example 1, the niobium content of the austenitic steel matrix in this comparative example is 0.2%. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming the composite material.

[0066] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.2% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0067] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0068] Comparative Example 4 This comparative example provides a method for preparing a composite material for a chain grate plate. Unlike Example 1, the niobium content of the austenitic steel matrix in this comparative example is 0.6%. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming the composite material.

[0069] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.6% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0070] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0071] Comparative Example 5 This comparative example provides a method for preparing a composite material for a chain grate. Unlike Example 1, the carbon content of the austenitic steel matrix in this comparative example is 0.2%. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel to form the composite material.

[0072] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.2% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0073] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0074] Comparative Example 6 This comparative example provides a method for preparing a composite material for a chain grate plate. Unlike Example 1, the carbon content of the austenitic steel matrix in this comparative example is 0.5%. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming the composite material.

[0075] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.5% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0076] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0077] Comparative Example 7 This comparative example provides a method for preparing a composite material for a chain grate. Unlike Example 1, the Fe3Al pre-alloyed powder in this comparative example contains 12% Al. Specifically, the Fe3Al pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium, forming a 0.5 mm thick Fe3Al coating on the austenitic steel to form the composite material.

[0078] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 12% Al and the balance is iron, with a particle size of 80 μm.

[0079] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0080] Comparative Example 8 This comparative example provides a method for preparing a composite material for a chain grate. Unlike Example 1, the Fe3Al pre-alloyed powder in this comparative example contains 21% Al. Specifically, the Fe3Al pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium, forming a 0.5 mm thick Fe3Al coating on the austenitic steel to form the composite material.

[0081] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 21% Al and the balance is iron, with a particle size of 80 μm.

[0082] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0083] Comparative Example 9 This comparative example provides a method for preparing a composite material for a chain grate. Unlike Example 1, the austenitic steel in this comparative example does not contain niobium. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming the composite material.

[0084] The austenitic steel matrix is ​​nitrogen-containing high-carbon austenitic stainless steel (chemical composition: 23.05% Cr, 9.15% Ni, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0085] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0086] Comparative Example 10 This comparative example provides a method for preparing a composite material for a chain grate. Unlike Example 1, the austenitic steel used in this comparative example does not contain carbon. Specifically, an iron-aluminum pre-alloyed powder is laser-clad onto high-carbon austenitic steel containing nitrogen and niobium to form a 0.5 mm thick Fe3Al coating on the austenitic steel, thereby forming the composite material.

[0087] The austenitic steel matrix is ​​a high-carbon austenitic stainless steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe). The Fe3Al pre-alloyed powder contains 13% Al and the balance is iron, with a particle size of 80 μm.

[0088] Specifically, the parameter information of laser cladding is: protective argon gas flow rate 10L / min, powder feeding argon gas flow rate 5L / min, powder feeding rate 8g / min, laser power 1200W, scanning speed 10mm / s, spot diameter 2mm, and defocus amount +2mm.

[0089] Comparative Example 11 This comparative example uses high carbon austenitic steel containing nitrogen and niobium (chemical composition: 23.05% Cr, 9.15% Ni, 0.3% Nb, 2% Mo, 1.2% Si, 1.3% Mn, 0.31% C, 0.4% N, 0.02% P, 0.02% S, and the balance is Fe), but no Fe3Al coating is applied on the high carbon austenitic steel containing nitrogen and niobium.

[0090] Comparative Example 12 This comparative example does not use high-carbon austenitic steel containing nitrogen and niobium as the substrate, nor does it use laser cladding Fe3Al coating. Instead, high-chromium and high-nickel 310S stainless steel is used as the grate plate material (chemical composition: 24.6% Cr, 19.5% Ni, 1.28% Mn, 0.42% Si, 0.08% C, 0.02% P, 0.02% S, and the balance is Fe).

[0091] The surface hardness of the samples in Examples 1 to 11 and Comparative Examples 1 to 12 was tested, and the test results are shown in Table 1 below.

[0092] Table 1

[0093] As can be seen from the table above, generally speaking, the hardness changes greatly before and after coating, and the substrate generally has a microhardness of 130HV 0.5 The coating hardness is generally about 500HV 0.5 . The high Ni content in Comparative Example 1 is not conducive to cost control. The reduction in coating hardness in Comparative Examples 2, 3, 9, and 10 is due to the fact that the coating does not contain niobium carbide particles or the amount of niobium carbide is small. The reduction in hardness in Comparative Examples 7 and 8 is due to the fact that the aluminum content in the cladding powder is not within the range, resulting in the coating phase not being a Fe3Al intermetallic compound, which leads to a decrease in hardness and a reduction in the wear resistance of the coating. The niobium content in Comparative Example 4 is as high as 0.6%. Although it is conducive to the formation of niobium carbide, the increase in Nb is not conducive to the close adhesion of the oxide film, which can easily cause the oxide film to fall off and reduce high-temperature oxidation resistance. The too low carbon content in Comparative Example 5 is not conducive to the full precipitation of niobium carbide; the excessively high carbon content in Comparative Example 6 will cause a large amount of chromium carbide to precipitate along the intergranular space, reducing the high-temperature durability mechanical properties of the base material. Comparative Examples 11 and 12 are uncoated, and their wear resistance is significantly lower than that of the coated samples.

[0094] The coating sample of Example 1 was subjected to a thermal shock test. The specific test method was as follows: the coating sample of Example 1 was placed in a ceramic crucible and then placed in a muffle furnace for heating at 800°C for 20 minutes. The sample was then taken out and air-cooled for 5 minutes. The sample was then placed in the muffle furnace again for heating for 20 minutes. This cycle was repeated for 10, 50, and 100 times of thermal shock simulation. The experimental results are shown in Figure 2. Figure 1-3 As shown, Figure 1 This is a SEM image of the interface of the coating sample of Example 1 after 10 cycles of thermal shock. Figure 2 This is the interface after 50 cycles of thermal shock. Figure 3 The interface after 100 cycles of thermal shock; Figure 1-3The test shows that the composite material prepared by the preparation method of the present invention has good impact resistance. After 100 cycles of thermal shock, the coating did not crack or peel off in any form, and the bonding interface between the coating and the substrate was good.

[0095] The substrate and coating materials of Example 1 were subjected to a high-temperature oxidation comparative test. The specific test method was as follows: first, a 15×10×3mm sample was cut from the material. Before the experiment, the six sides of the sample were polished on 80#, 240#, 400#, 800#, and 1000# sandpaper, respectively. After cleaning with alcohol, the sample was blotted dry with filter paper and placed in a vacuum drying oven for future use. The oxidation method adopted a cyclic oxidation method, and the metal oxidation rate was determined by mass method, and the weight was weighed by discontinuous weighing method. In this experiment, the sample was subjected to constant temperature oxidation at a temperature of 800°C under normal atmospheric composition and atmospheric pressure. The oxidation time was 10h-120h, and the cycle period was 10h. After the experiment was completed, the oxidation weight gain and oxidation rate were calculated. A 20ml alumina crucible with a volume matched to each sample was used. After cleaning and drying, the crucible was placed in a box-type resistance furnace and heated at 1000°C for 2h. The sample was dried and unstable impurities were removed to ensure that its mass remained constant during the high-temperature oxidation experiment. The experimental results are as follows Figure 4-7 As shown, Figure 4 This is the high temperature oxidation morphology of the base stainless steel. Figure 5 is the oxidation corrosion rate curve per unit area of ​​base stainless steel, Figure 6 This is the high temperature oxidation morphology of Fe3Al. Figure 7 This is the Fe3Al unit area oxidation corrosion rate curve. The test shows that the average oxidation rate of the base stainless steel material is 1.71 g / m 2 *h, the average oxidation rate of Fe3Al is 0.787 g / m 2 *h, it can be seen that the oxidation resistance of Fe3Al is better than that of the base stainless steel material. The high-temperature oxidation corrosion rate of Fe3Al is about 46.02% of that of the grate material, that is, the high-temperature oxidation service life of the former is 2.17 times that of the latter.

[0096] A high-temperature oxidation comparative test was conducted on the base material and coating material of the above-mentioned embodiment 1. The specific test method is as follows: as in the high-temperature oxidation test, first cut a 15×10×3mm sample from the material. Before the experiment, polish the six sides of the sample on 80#, 240#, 400#, 800#, and 1000# sandpaper respectively. After cleaning with alcohol, dry it with filter paper and store it in a vacuum drying oven for later use. At room temperature, a saturated mixed salt solution was prepared using pure KCl, NaCl, K2SO4, and Na2SO4 reagents. The ratio was: 10% KCl + 10% NaCl + 40% K2SO4 + 40% Na2SO4. The solvent was deionized water. The weighed mixed salt was placed in a beaker filled with deionized water. If there was any residual salt after dissolution, it meant that the solution was saturated. The upper layer of solution was taken for use. The amount of mixed salt applied to the sample surface was 3mg / cm 2 Before applying the mixed salt on the sample surface, it is necessary to measure the length, width and height of the sample three times, take the average value, and then calculate the surface area of ​​the sample, which is recorded as S (unit: cm 2 ), measure the sample weight on a precision electronic balance, record it as m1 (in mg). The sample weight after mixed salt coating is 3S + m1 (in mg): Place the sample on an asbestos mesh, then apply a saturated mixed salt solution. Evaporate the water, cool it, and weigh it on a precision electronic balance, record it as m2 (in mg). After salt coating, ensure that m2 ≈ 3S + m1. The high-temperature mixed salt corrosion test is conducted in a box-type resistance furnace: First, raise the box-type resistance furnace to the test temperature, which is 800°C. Place the mixed salt film sample in a crucible that has been dried to a constant weight. Measure the total weight on a precision electronic balance, record it as M1 (in mg). Place it in the box-type resistance furnace to maintain heat. After the test time is reached (corrosion time ranges from 10h to 120h, with a 10h cycle), remove the crucible, cover it, and place it in a desiccating dish to cool to room temperature. Then weigh the total weight of the crucible and sample on a precision electronic balance, record it as M2 (in mg). Corrosion weight gain rate of the sample △M (unit: mg • cm -2 ) is calculated using the following formula: △M =(M2-M1) / S.

[0097] The experimental results are as follows Figure 8-11 As shown, Figure 8 This is the high temperature salt corrosion morphology of the base stainless steel. Figure 9 is the high temperature salt corrosion rate curve per unit area of ​​base stainless steel, Figure 10 This is the high temperature salt corrosion morphology of Fe3Al. Figure 11This is the high-temperature salt corrosion rate curve per unit area of ​​Fe3Al. The test shows that in the presence of salt, both materials exhibit more intense corrosion behavior, and the average corrosion rate of the base stainless steel material reaches 4.67 g / m 2 *h, the average corrosion rate of Fe3Al reached 1.89g / m 2 The high-temperature salt corrosion rate of Fe3Al is approximately 40.47% of that of the grate material, meaning that the high-temperature salt corrosion resistance service life of the former is 2.47 times that of the latter.

[0098] Friction and wear tests were conducted on the composite material surface of Example 1 using a reciprocating friction and wear tester at room temperature. The test pair consisted of 5-mm-diameter Si3N4 ceramic balls, with a load of 25 N, a reciprocating frequency of 3 Hz, a wear track length of 5 mm, and a friction time of 60 minutes. Wear volume was measured using a 3D digital microscope, and the volume wear rate was calculated using the formula.

[0099] Gr=ΔV / FL.

[0100] Gr is the volume wear rate, in mm 3 / (m•N); ΔV is the wear volume, unit is mm 3 ; F is the load, unit is N; L is the total friction and wear stroke, unit is m. The volume wear rate of the sample after cladding treatment is 3.4mm 3 ×10 - 5 mm 3 / N·m, which is much lower than the wear rate of the substrate sample before cladding treatment (7.7 mm 3 ×10 -5 mm 3 / N·m, a decrease of 55.8%. After cladding treatment, the surface hardness of the sample is approximately 500 HV, much higher than the substrate hardness of ~130 HV before cladding. This makes it more capable of resisting external loads during friction and wear, and its plastic deformation is smaller and more uniform, resulting in more stable wear behavior.

[0101] The samples in Comparative Example 12 were subjected to the same high temperature oxidation and high temperature salt corrosion tests, and the test results are shown in Table 1. Figure 12-15 . Figure 12 This is the high temperature oxidation morphology of 310S stainless steel. Figure 13 This is the oxidation corrosion rate curve per unit area of ​​310S stainless steel. Figure 14 This is the high temperature oxidation morphology of 310S. Figure 15 The 310S unit area oxidation corrosion rate curve is shown in Figure 2. The average oxidation rate of 310S is 1.891 g / m 2*h, the average salt corrosion rate reached 5.89 g / m 2 *h, which are higher than the corresponding rates of high carbon austenitic steel containing nitrogen and niobium and Fe3Al.

[0102] Finally, it should be noted that the specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention. For those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or basic features of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present application is limited by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present application.

Claims

1. A chain grate plate composite material, characterized in that: The invention comprises a heat-resistant stainless steel component and a coating component. The heat-resistant stainless steel component comprises austenitic steel containing nitrogen and niobium elements. The coating component is an iron-aluminum alloy containing niobium carbide particles.

2. A chain grate plate composite material according to claim 1, characterized in that: The heat-resistant stainless steel composition also includes chromium, nickel, niobium, molybdenum, silicon, manganese, carbon, nitrogen, phosphorus and sulfur.

3. A chain grate plate composite material according to claim 2, characterized in that: The mass percentages of the elements in the heat-resistant stainless steel component are: 23% to 25% chromium, 9% to 10% nickel, 0.3% to 0.5% niobium, 2% to 3% molybdenum, 1% to 2% silicon, 1% to 2% manganese, 0.3% to 0.4% carbon, 0.4% to 0.6% nitrogen, <0.03% phosphorus, <0.03% sulfur, and the balance iron.

4. The chain grate plate composite material according to claim 1, characterized in that: The mass percentage of aluminum element in the iron-aluminum alloy is 13% to 20%, and the balance is iron.

5. A method for preparing a chain grate plate composite material, characterized in that: Iron-aluminum pre-alloyed powder is clad on austenitic steel containing nitrogen and niobium elements by laser cladding method to form a coating on the austenitic steel to form a composite material.

6. The method for preparing a composite material for a chain grate according to claim 5, characterized in that: The particle size of the iron-aluminum pre-alloyed powder is 80 μm to 150 μm.

7. The method for preparing a composite material for a chain grate according to claim 5, characterized in that: The thickness of the coating is 0.5 mm to 1.5 mm.

8. The method for preparing a composite material for a chain grate according to claim 5, wherein: When using the laser cladding method to prepare the coating, the laser power is controlled at 700W~1500W, the laser scanning speed is controlled at 3mm / s~10mm / s, the spot diameter is 2mm~3mm, and the defocus amount is +2mm~+10mm.

9. The method for preparing a composite material for a chain grate according to claim 5, wherein: The laser cladding is performed under an inert gas, which is argon.

10. The method for preparing a composite material for a chain grate according to claim 9, characterized in that: The flow rate of protective argon gas is controlled at 10L / min~15 L / min; the flow rate of powder feeding argon gas is controlled at 5L / min~9 L / min, and the powder feeding rate is 8g / min~20g / min.

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