A high-temperature erosion-wear resistant gradient surfacing layer and its preparation method and application

Abstract

The invention discloses a gradient surfacing layer resistant to high-temperature erosion and wear, comprising a base layer and a capping layer, wherein the capping layer is arranged above the base layer, the base layer is made by surfacing welding of a base layer welding wire, and the capping layer is made by surfacing welding of a capping layer welding wire; the base layer welding wire comprises a powder A and a welding skin wrapped around the powder A, wherein the powder A comprises the following components in mass percentage: Ni 70.0-80.0%, Nb 6-8%, Ti 1.0-1.5%, CeO2 0.5-1.0%, and the remainder is Fe, and the sum of the mass percentages of the above components is 100%; the capping layer welding wire comprises a powder B and a welding skin wrapped around the powder B, wherein the powder B comprises the following components in mass percentage: Cr 40.0-50.0%, Ni 20.0-25.0%, C 2-4%, Ti 2-4%, Al 5-8%, La2O3 The gradient cladding layer of the present invention is suitable for surface protection of heating surface areas prone to erosion and wear in power plant boilers, and can effectively reduce the erosion thinning rate, thereby ensuring the service safety of the pipeline.

Description

Technical Field

[0001] The present invention belongs to the technical field of welding materials, and in particular relates to a gradient surfacing layer resistant to high-temperature erosion and wear, and a preparation method and application thereof. Background Art

[0002] Electricity has become an indispensable form of energy utilization in human production and daily life. In my country, thermal power generation is the primary method of electricity production. In 2018, my country's installed thermal power capacity reached 1.14 billion kilowatts, accounting for approximately 61% of the total installed power generation capacity. This demonstrates the crucial importance of thermal power generation in my country's electricity production. Boilers are a key energy conversion device in thermal power plants, converting the chemical energy in fuels such as coal, biomass, or household waste into thermal energy in working fluids such as boiler water or steam, which in turn drives the turbine to generate power and the generator to produce electricity. When solid fuels such as coal, biomass, and household waste are burned, in addition to the heat released by the combustible components, incombustible components and unburned materials remain as solid particles such as bottom ash or fly ash, causing erosion and wear on the boiler's heating surfaces.

[0003] Erosive wear refers to the material loss caused by small solid particles impacting a material surface at a specific speed and angle. Erosive wear damage to the heating surfaces of power plant boilers primarily occurs on the fire-facing side. Carried by the high-temperature flue gases from combustion, fly ash particles scour the heating surfaces, causing surface material loss and thinning of the heat exchange tube walls. Long-term erosion can even lead to tube damage, fluid leakage, and, in severe cases, tube bursts, compromising the safe and stable operation of the boiler. Maintenance shutdowns due to fluid leakage and tube bursts caused by erosive wear account for over 40% of all boiler outages. These outages not only disrupt electricity supply but also inflict significant economic losses on power plants, with a single outage costing hundreds of thousands or even millions of yuan.

[0004] The Chinese patent application number CN202310697983.8 discloses a Ni-Cr welding wire resistant to high temperature hydrogen sulfide corrosion and its preparation method, which relates to the field of welding material technology and is designed to solve the problem that furnace tubes are susceptible to hydrogen sulfide corrosion. The Ni-Cr welding wire resistant to high temperature hydrogen sulfide corrosion includes an outer sheath and a flux core filled in the outer sheath; the outer sheath is Cr 30 Ni 70The flux core comprises, in percentage by mass of the total flux core mass, Cr: 50.0%-60.0%, Nb: 4.0%-6.0%, Al: 2.0%-4.0%, Cu: 4.0%-6.0%, Fe: 1.0%-1.5%, and the remainder is Ni. The Ni-Cr welding wire resistant to high-temperature hydrogen sulfide corrosion provided by the invention achieves excellent high-temperature resistance through the elements Cr, Nb, Al, and Cu. In combination with the CMT welding technology, a well-formed overlay layer with low dilution rate is obtained. However, the invention only uses a single overlay layer, which may not achieve high hardness and high wear resistance, and a single overlay layer may cause large residual stresses, which may cause defects such as cracks or peeling. Therefore, there is an urgent need to design a overlay layer that can achieve high-temperature resistance, erosion resistance, and wear resistance for the harsh working conditions inside the boiler. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a gradient surfacing layer that is resistant to high-temperature erosion and wear, as well as its preparation method and application. It is suitable for surface protection of heated surface areas in power plant boilers that are prone to erosion and wear, and can effectively reduce the erosion thinning rate, thereby ensuring the service safety of the pipeline.

[0006] The technical solutions of the present invention are as follows:

[0007] One of the purposes of the present invention is to provide a gradient surfacing layer resistant to high temperature erosion and wear, comprising a base layer and a capping layer, wherein the capping layer is arranged above the base layer, the base layer is made by surfacing welding with base layer welding wire, and the capping layer is made by surfacing welding with capping layer welding wire;

[0008] The base layer welding wire includes powder A and a welding skin wrapped around the powder A, wherein the powder A is composed of the following components in mass percentage: Ni 70.0-80.0%, Nb 6-8%, Ti 1.0-1.5%, CeO2 0.5-1.0%, and the balance Fe, and the sum of the mass percentages of the above components is 100%;

[0009] The cover layer welding wire includes powder B and a welding skin wrapped around the powder B. The powder B is composed of the following components in mass percentage: Cr 40.0-50.0%, Ni 20.0-25.0%, C 2-4%, Ti 2-4%, Al 5-8%, La2O3 3-5%, and the rest is Fe, and the sum of the mass percentages of the above components is 100%.

[0010] Furthermore, the particle size of the medicine powder A and the medicine powder B are both 100-200 mesh.

[0011] Furthermore, the material of the weld skin in the base layer welding wire and the cover layer welding wire is 430 steel strip.

[0012] Furthermore, the thickness of the weld skin in the base layer welding wire and the cover layer welding wire is 0.4 mm, and the width is 7 mm.

[0013] Furthermore, the filling rate of the powder A in the base layer welding wire is 20-22%.

[0014] Furthermore, the filling rate of the powder B in the cover layer welding wire is 18-20%.

[0015] Furthermore, the preparation method of the base layer welding wire comprises the following steps:

[0016] S11: Weigh Ni, Nb, Ti, CeO2, and Fe according to a set ratio, heat them in a vacuum heating furnace at 200-220°C for 1-4 hours to remove crystal water in the raw materials, and mix the heated raw materials in a powder mixer for 1-4 hours to obtain drug powder A;

[0017] S12: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0018] S13: After the first drawing process is completed, several drawing processes are set in sequence, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the base layer welding wire finally obtained is 1.0-1.2 mm.

[0019] Furthermore, the method for preparing the cover layer welding wire comprises the following steps:

[0020] S21: Weigh Cr, Ni, C, Ti, Al, La2O3, and Fe according to a set ratio, heat them in a vacuum heating furnace at 220-230°C for 2-4 hours to remove crystal water in the powder, and place the heated raw materials in a powder mixer for 1-2 hours to obtain powder B;

[0021] S22: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0022] S23: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the final cover layer welding wire is 1.0-1.2 mm.

[0023] A second object of the present invention is to provide a method for preparing a gradient surfacing layer resistant to high temperature erosion and wear, comprising the following steps:

[0024] S31: Using a base layer welding wire to perform overlay welding on the substrate to obtain a base layer, wherein the overlay welding current is 140-160A, the overlay layer thickness is 1.5-2.0mm, the swing width is 10-15mm, the overlap is 2-3mm, one overlay layer is welded, and the shielding gas is 98% Ar + 2% O2;

[0025] S32: Use a cover layer welding wire to perform overlay welding on the base layer prepared in step S31 to obtain a cover layer, wherein the overlay welding current is 160-180A, the overlay welding layer thickness is 1.5-2.0mm, the swing width is 15-20mm, the overlap amount is 3-4mm, one layer is overlayed, and the shielding gas is 98% Ar + 2% O2.

[0026] A third object of the present invention is to provide an application of any of the above-mentioned gradient surfacing layers or the gradient surfacing layers prepared according to the above-mentioned preparation method in the heating surface of a power plant boiler.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. This invention provides a gradient weld overlay layer that resists high-temperature erosion and wear. Designed for the harsh service conditions within boilers, the gradient weld overlay layer comprises a base layer primarily composed of an Fe-Ni-Nb alloy, offering excellent toughness and ensuring excellent metallurgical bonding strength and ductility with the heated surface tubes. The cap layer, primarily composed of an Fe-Cr-Ni-Al alloy, effectively reduces the rate of ash fly erosion and thinning at high temperatures, ensuring high-temperature erosion resistance. This gradient structure, employed in this invention, offers superior high-temperature service performance compared to a single weld overlay structure.

[0029] 2. The base layer welding wire of this invention incorporates a large amount of Ni, ensuring high-temperature performance while also ensuring strong bonding between the base layer and the pipe substrate. The addition of Nb further enhances the base layer's stability at high temperatures. A small amount of rare earth element CeO2 is also added to the base layer welding wire. This rare earth oxide purifies grain boundaries and enhances grain boundary bonding strength, further strengthening the bonding between the base layer and the substrate.

[0030] 3. In the cover layer welding wire of the present invention, a large amount of Cr element can fully ensure the high-temperature performance of the cover weld, the Al element can further improve the high-temperature oxidation resistance of the cover weld, and the C and Ti elements have a solid solution strengthening effect on the one hand, and on the other hand can generate TiC in situ, which plays a role in pinning grain boundaries, refining grains, and improving the high-temperature stability of the cover layer. La2O3 plays a role in further purifying the grain boundaries.

[0031] 4. The gradient surfacing layer of the present invention is suitable for surface protection of heating surface areas in power plant boilers that are prone to erosion and wear, and can effectively reduce the erosion thinning rate, thereby ensuring the service safety of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The metallographic structure of the base layer of the surfacing layer of Example 2 of the present invention;

[0033] Figure 2 The metallographic structure of the capping layer of the surfacing layer of Example 2 of the present invention;

[0034] Figure 3 This is the scanning electron microscope observation result of the morphology of the surfacing layer of Example 2 after high-temperature erosion in the present invention. DETAILED DESCRIPTION

[0035] Below in conjunction with preferred embodiment, and referring to attached Figure 1-3 , to further illustrate the present invention, the endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values; for numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein; the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels; the experimental methods in the following examples, unless otherwise specified, are all conventional methods.

[0036] Example 1

[0037] This embodiment provides a gradient surfacing layer resistant to high temperature erosion and wear, comprising a base layer and a capping layer, wherein the capping layer is disposed above the base layer, the base layer is made by surfacing welding with base layer welding wire, and the capping layer is made by surfacing welding with capping layer welding wire;

[0038] The base layer welding wire includes a flux A and a welding skin wrapped around the flux A, wherein the flux A is composed of the following components in mass percentage: Ni 70.0%, Nb 6%, Ti 1.0%, CeO2 0.5%, and the balance Fe, and the sum of the mass percentages of the above components is 100%;

[0039] The cover layer welding wire includes powder B and a welding skin wrapped around the powder B. The powder B is composed of the following components in mass percentage: Cr 40.0%, Ni 20.0%, C 2%, Ti 2%, Al 5%, La2O3 3%, and the rest is Fe, and the sum of the mass percentages of the above components is 100%.

[0040] In this embodiment, the particle size of the powder A and the powder B are both 100 mesh, the material of the weld skin in the base layer welding wire and the cover layer welding wire is 430 steel strip, the thickness of the weld skin in the base layer welding wire and the cover layer welding wire is both 0.4 mm, and the width is 7 mm. The filling rate of the powder A in the base layer welding wire is 20%, and the filling rate of the powder B in the cover layer welding wire is 18%.

[0041] In this embodiment, the preparation method of the base layer welding wire includes the following steps:

[0042] S11: Ni, Nb, Ti, CeO2, and Fe were weighed in a set ratio, placed in a vacuum heating furnace at 200°C and heated for 1 hour to remove crystal water in the raw materials. The heated raw materials were then placed in a powder mixer and mixed for 1 hour to obtain drug powder A;

[0043] S12: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0044] S13: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the base layer welding wire finally obtained is 1.0 mm.

[0045] In this embodiment, the method for preparing the cover layer welding wire includes the following steps:

[0046] S21: Cr, Ni, C, Ti, Al, La2O3, and Fe were weighed in a set ratio and heated in a vacuum heating furnace at 220°C for 2 hours to remove crystal water in the powder. The heated raw materials were then mixed in a powder mixer for 1 hour to obtain powder B.

[0047] S22: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0048] S23: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the final cover layer welding wire is 1.0 mm.

[0049] This embodiment also provides a method for preparing a gradient surfacing layer resistant to high-temperature erosion and wear, comprising the following steps:

[0050] S31: Using a base layer welding wire, surfacing welding is performed on the surface of 12Cr1MoV to obtain a base layer, wherein the surfacing current is 140A, the surfacing layer thickness is 1.5mm, the swing width is 10mm, the overlap is 2mm, and one surfacing layer is welded. The shielding gas is 98% Ar + 2% O2;

[0051] S32: Use a cover layer welding wire to perform overlay welding on the base layer prepared in step S31 to obtain a cover layer, wherein the overlay welding current is 160A, the overlay welding layer thickness is 1.5mm, the swing width is 15mm, the overlap amount is 3mm, 1 layer is overlay welded, and the shielding gas is 98% Ar + 2% O2.

[0052] Example 2

[0053] This embodiment provides a gradient surfacing layer resistant to high temperature erosion and wear, comprising a base layer and a capping layer, wherein the capping layer is disposed above the base layer, the base layer is made by surfacing welding with base layer welding wire, and the capping layer is made by surfacing welding with capping layer welding wire;

[0054] The base layer welding wire includes a flux A and a welding skin wrapped around the flux A, wherein the flux A is composed of the following components in mass percentage: Ni 80.0%, Nb 8%, Ti 1.5%, CeO2 1.0%, and the balance Fe, and the sum of the mass percentages of the above components is 100%;

[0055] The cover layer welding wire includes powder B and a welding skin wrapped around the powder B. The powder B is composed of the following components in mass percentage: 50.0% Cr, 25.0% Ni, 4% C, 4% Ti, 8% Al, 5% La2O3, and the rest Fe, and the sum of the mass percentages of the above components is 100%.

[0056] In this embodiment, the particle size of the powder A and the powder B are both 200 mesh, the material of the weld skin in the base layer welding wire and the cover layer welding wire is 430 steel strip, the thickness of the weld skin in the base layer welding wire and the cover layer welding wire is both 0.4 mm, and the width is 7 mm. The filling rate of the powder A in the base layer welding wire is 22%, and the filling rate of the powder B in the cover layer welding wire is 20%.

[0057] In this embodiment, the preparation method of the base layer welding wire includes the following steps:

[0058] S11: Ni, Nb, Ti, CeO2, and Fe were weighed according to a set ratio, and heated in a vacuum heating furnace at 220°C for 4 hours to remove crystal water in the raw materials. The heated raw materials were then mixed in a powder mixer for 4 hours to obtain drug powder A;

[0059] S12: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0060] S13: After the first drawing process is completed, several drawing processes are set in sequence. The aperture of the drawing die corresponding to each drawing process is reduced in sequence, and the diameter of the base layer welding wire finally obtained is 1.2 mm.

[0061] In this embodiment, the method for preparing the cover layer welding wire includes the following steps:

[0062] S21: Cr, Ni, C, Ti, Al, La2O3, and Fe were weighed in a set ratio and heated in a vacuum furnace at 230°C for 4 hours to remove crystal water in the powder. The heated raw materials were then mixed in a powder mixer for 2 hours to obtain powder B.

[0063] S22: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0064] S23: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the final cover layer welding wire is 1.2 mm.

[0065] This embodiment also provides a method for preparing a gradient surfacing layer resistant to high-temperature erosion and wear, comprising the following steps:

[0066] S31: Using a base layer welding wire, surfacing welding is performed on the surface of 12Cr1MoV to obtain a base layer, wherein the surfacing current is 160A, the surfacing layer thickness is 2.0mm, the swing width is 15mm, the overlap is 3mm, and one surfacing layer is welded. The shielding gas is 98% Ar + 2% O2;

[0067] S32: Use a cover layer welding wire to perform overlay welding on the base layer prepared in step S31 to obtain a cover layer, wherein the overlay welding current is 180A, the overlay welding layer thickness is 2.0mm, the swing width is 20mm, the overlap amount is 4mm, 1 layer is overlayed, and the shielding gas is 98% Ar+2% O2.

[0068] Example 3

[0069] This embodiment provides a gradient surfacing layer resistant to high temperature erosion and wear, comprising a base layer and a capping layer, wherein the capping layer is disposed above the base layer, the base layer is made by surfacing welding with base layer welding wire, and the capping layer is made by surfacing welding with capping layer welding wire;

[0070] The base layer welding wire includes a flux A and a welding skin wrapped around the flux A, wherein the flux A is composed of the following components in mass percentage: Ni 75.0%, Nb 7%, Ti 1.3%, CeO2 0.7%, and the balance Fe, and the sum of the mass percentages of the above components is 100%;

[0071] The cover layer welding wire includes powder B and a welding skin wrapped around the powder B. The powder B is composed of the following components in mass percentage: Cr 45.0%, Ni 23.0%, C 3.0%, Ti 3.0%, Al 7.5%, La2O34%, and the rest is Fe, and the sum of the mass percentages of the above components is 100%.

[0072] In this embodiment, the particle size of the powder A and the powder B are both 150 mesh, the material of the weld skin in the base layer welding wire and the cover layer welding wire is 430 steel strip, the thickness of the weld skin in the base layer welding wire and the cover layer welding wire is both 0.4 mm, and the width is 7 mm. The filling rate of the powder A in the base layer welding wire is 21%, and the filling rate of the powder B in the cover layer welding wire is 19%.

[0073] In this embodiment, the preparation method of the base layer welding wire includes the following steps:

[0074] S11: Ni, Nb, Ti, CeO2, and Fe were weighed in a set ratio, placed in a vacuum heating furnace at 210°C and heated for 2.5 hours to remove crystal water in the raw materials. The heated raw materials were then placed in a powder mixer and mixed for 2.5 hours to obtain drug powder A;

[0075] S12: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0076] S13: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the base layer welding wire finally obtained is 1.1 mm.

[0077] In this embodiment, the method for preparing the cover layer welding wire includes the following steps:

[0078] S21: Cr, Ni, C, Ti, Al, La2O3, and Fe were weighed in a predetermined ratio and heated in a vacuum furnace at 210°C for 3 hours to remove crystal water from the powder. The heated raw materials were then mixed in a powder mixer for 1.5 hours to obtain powder B.

[0079] S22: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0080] S23: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the final cover layer welding wire is 1.1 mm.

[0081] This embodiment also provides a method for preparing a gradient surfacing layer resistant to high-temperature erosion and wear, comprising the following steps:

[0082] S31: Using a base layer welding wire, surfacing welding is performed on the surface of 12Cr1MoV to obtain a base layer, wherein the surfacing current is 150A, the surfacing layer thickness is 1.7mm, the swing width is 13mm, the overlap is 2.5mm, and one surfacing layer is welded. The shielding gas is 98% Ar + 2% O2;

[0083] S32: Use a cover layer welding wire to perform overlay welding on the base layer prepared in step S31 to obtain a cover layer, wherein the overlay welding current is 170A, the overlay welding layer thickness is 1.7mm, the swing width is 17mm, the overlap amount is 3.5mm, 1 layer is overlay welded, and the shielding gas is 98% Ar + 2% O2.

[0084] Example 4

[0085] This embodiment provides a gradient surfacing layer resistant to high temperature erosion and wear, comprising a base layer and a capping layer, wherein the capping layer is disposed above the base layer, the base layer is made by surfacing welding with base layer welding wire, and the capping layer is made by surfacing welding with capping layer welding wire;

[0086] The base layer welding wire includes a flux A and a welding skin wrapped around the flux A, wherein the flux A is composed of the following components in mass percentage: Ni 78.0%, Nb 6.8%, Ti 1.2%, CeO2 0.6%, and the balance Fe, and the sum of the mass percentages of the above components is 100%;

[0087] The cover layer welding wire includes powder B and a welding skin wrapped around the powder B. The powder B is composed of the following components in mass percentage: Cr 43.0%, Ni 22.0%, C 2.4%, Ti 2.4%, Al 5.8%, La2O33.5%, and the rest is Fe. The sum of the mass percentages of the above components is 100%.

[0088] In this embodiment, the particle size of the powder A and the powder B are both 200 mesh, the material of the weld skin in the base layer welding wire and the cover layer welding wire is 430 steel strip, the thickness of the weld skin in the base layer welding wire and the cover layer welding wire is both 0.4 mm, and the width is 7 mm. The filling rate of the powder A in the base layer welding wire is 20%, and the filling rate of the powder B in the cover layer welding wire is 20%.

[0089] In this embodiment, the preparation method of the base layer welding wire includes the following steps:

[0090] S11: Ni, Nb, Ti, CeO2, and Fe were weighed in a set ratio and heated in a vacuum furnace at 215°C for 1.4 hours to remove crystal water from the raw materials. The heated raw materials were then mixed in a powder mixer for 1.4 hours to obtain drug powder A.

[0091] S12: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0092] S13: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the base layer welding wire finally obtained is 1.1 mm.

[0093] In this embodiment, the method for preparing the cover layer welding wire includes the following steps:

[0094] S21: Cr, Ni, C, Ti, Al, La2O3, and Fe were weighed in a predetermined ratio and heated in a vacuum furnace at 222°C for 2.4 hours to remove crystal water from the powder. The heated raw materials were then mixed in a powder mixer for 1.2 hours to obtain powder B.

[0095] S22: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0096] S23: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the final cover layer welding wire is 1.1 mm.

[0097] This embodiment also provides a method for preparing a gradient surfacing layer resistant to high-temperature erosion and wear, comprising the following steps:

[0098] S31: Using a base layer welding wire, surfacing welding is performed on the surface of 12Cr1MoV to obtain a base layer, wherein the surfacing current is 150A, the surfacing layer thickness is 1.8mm, the swing width is 12mm, the overlap is 2.3mm, and one surfacing layer is welded. The shielding gas is 98% Ar + 2% O2;

[0099] S32: Use a cover layer welding wire to perform overlay welding on the base layer prepared in step S31 to obtain a cover layer, wherein the overlay welding current is 170A, the overlay welding layer thickness is 1.8mm, the swing width is 16mm, the overlap amount is 3.4mm, 1 layer is overlay welded, and the shielding gas is 98% Ar + 2% O2.

[0100] Example 5

[0101] This embodiment provides a gradient surfacing layer resistant to high temperature erosion and wear, comprising a base layer and a capping layer, wherein the capping layer is disposed above the base layer, the base layer is made by surfacing welding with base layer welding wire, and the capping layer is made by surfacing welding with capping layer welding wire;

[0102] The base layer welding wire includes a flux A and a welding skin wrapped around the flux A, wherein the flux A is composed of the following components in mass percentage: Ni 71.0%, Nb 6.9%, Ti 1.4%, CeO2 0.9%, and the balance Fe, and the sum of the mass percentages of the above components is 100%;

[0103] The cover layer welding wire includes powder B and a welding skin wrapped around the powder B. The powder B is composed of the following components in mass percentage: Cr 41.0%, Ni 24.0%, C 3.5%, Ti 3.8%, Al 7.8%, La2O33.1%, and the rest is Fe. The sum of the mass percentages of the above components is 100%.

[0104] In this embodiment, the particle size of the powder A and the powder B are both 150 mesh, the material of the weld skin in the base layer welding wire and the cover layer welding wire is 430 steel strip, the thickness of the weld skin in the base layer welding wire and the cover layer welding wire is both 0.4 mm, and the width is 7 mm. The filling rate of the powder A in the base layer welding wire is 21%, and the filling rate of the powder B in the cover layer welding wire is 19%.

[0105] In this embodiment, the preparation method of the base layer welding wire includes the following steps:

[0106] S11: Ni, Nb, Ti, CeO2, and Fe were weighed in a set ratio, placed in a vacuum heating furnace at 218°C and heated for 3 hours to remove crystal water in the raw materials. The heated raw materials were then placed in a powder mixer and mixed for 3 hours to obtain drug powder A;

[0107] S12: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0108] S13: After the first drawing process is completed, several drawing processes are set in sequence. The aperture of the drawing die corresponding to each drawing process is reduced in sequence, and the diameter of the base layer welding wire finally obtained is 1.2 mm.

[0109] In this embodiment, the method for preparing the cover layer welding wire includes the following steps:

[0110] S21: Cr, Ni, C, Ti, Al, La2O3, and Fe were weighed in a predetermined ratio and heated in a vacuum furnace at 229°C for 3.8 hours to remove crystal water from the powder. The heated raw materials were then mixed in a powder mixer for 1.1 hours to obtain powder B.

[0111] S22: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm;

[0112] S23: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the final cover layer welding wire is 1.2 mm.

[0113] This embodiment also provides a method for preparing a gradient surfacing layer resistant to high-temperature erosion and wear, comprising the following steps:

[0114] S31: Using a base layer welding wire, surfacing welding is performed on the surface of 12Cr1MoV to obtain a base layer, wherein the surfacing current is 150A, the surfacing layer thickness is 1.9mm, the swing width is 14mm, the overlap is 2.6mm, and one surfacing layer is welded. The shielding gas is 98% Ar + 2% O2;

[0115] S32: Use a cover layer welding wire to perform overlay welding on the base layer prepared in step S31 to obtain a cover layer, wherein the overlay welding current is 170A, the overlay welding layer thickness is 1.9mm, the swing width is 19mm, the overlap amount is 3.7mm, 1 layer is overlay welded, and the shielding gas is 98% Ar + 2% O2.

[0116] Comparative Example 1

[0117] The difference from Example 2 is that the surfacing layer of this comparative example does not include a capping layer.

[0118] Comparative Example 2

[0119] The difference from Example 2 is that the surfacing layer of this comparative example does not include a base layer, and the cover layer welding wire of this comparative example is directly surfacing-welded on the surface of 12Cr1MoV.

[0120] Comparative Example 3

[0121] The difference from Example 2 is that the base layer of this comparative example is made by surfacing welding with ERNiCrMo-3 welding wire, which is composed of the following components by mass percentage: 22.18% Cr, 3.76% Nb, 9.27% ​​Mo, 0.1% Fe, and the balance Ni.

[0122] Comparative Example 4

[0123] The difference from Example 2 is that the cover layer of this comparative example is made by surfacing welding with ERNiCrCoMo-1 welding wire, which is composed of the following components by mass percentage: 22.92% Cr, 12.08% Co, 9.12% Mo, 0.43% Fe, and the balance Ni.

[0124] Implementation effect evaluation

[0125] The excellent effects achieved by the present invention are further illustrated below by conducting specific tests on the surfacing layers of Examples 1-5 and Comparative Examples 1-4.

[0126] The test results are shown in the table below:

[0127] Table 1 Statistics of weld overlay performance test results

[0128]

[0129]

[0130] As can be seen from the above table, the gradient surfacing layer provided by the present invention has very high hardness and bonding strength, can effectively reduce the dust flying erosion thinning rate under high temperature, and ensure high temperature erosion resistance.

[0131] Figure 1 This is the metallographic structure of the base layer of the cladding layer in Example 2. Figure 1 It can be seen that the base layer presents a columnar dendrite morphology. Judging from the element content, its organizational composition is mainly austenite + martensite.

[0132] Figure 2 This is the metallographic structure of the cap layer of the cladding layer in Example 2. Figure 2 It can be seen from the figure that the cover layer structure is mainly composed of ferrite, austenite structure is distributed at the ferrite grain boundary, and there are precipitated phases in the grains.

[0133] Figure 3The scanning electron microscope observation results of the high-temperature erosion morphology of the cladding layer in Example 2 are shown. As can be seen from the figure, the erosion morphology is relatively uniform, indicating that the cladding layer has a strong ability to resist erosion at high temperatures.

[0134] The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the creative concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A gradient surfacing layer resistant to high temperature erosion and wear, characterized in that: It comprises a base layer and a cover layer, wherein the cover layer is arranged above the base layer, the base layer is made by surfacing welding with base layer welding wire, and the cover layer is made by surfacing welding with cover layer welding wire; The base layer welding wire includes powder A and a welding skin wrapped around the powder A, wherein the powder A is composed of the following components in mass percentage: Ni 70.0-80.0%, Nb 6-8%, Ti 1.0-1.5%, CeO2 0.5-1.0%, and the balance Fe, and the sum of the mass percentages of the above components is 100%; The cover layer welding wire includes a flux B and a welding skin wrapped around the flux B, wherein the flux B is composed of the following components in mass percentage: Cr 40.0-50.0%, Ni 20.0-25.0%, C 2-4%, Ti 2-4%, Al 5-8%, La2O3 3-5%, and the remainder is Fe, and the sum of the mass percentages of the above components is 100%; The material of the welding skin of the base layer welding wire and the cover layer welding wire is 430 steel strip; The thickness of the welding wire in the bottom layer and the cover layer is 0.4 mm, and the width is 7 mm. The filling rate of the powder A in the base welding wire is 20-22%; The filling rate of the powder B in the cover layer welding wire is 18-20%.

2. The high-temperature erosion and wear-resistant gradient surfacing layer according to claim 1, characterized in that: The particle sizes of the medicinal powder A and the medicinal powder B are both 100-200 meshes.

3. A high temperature erosion wear resistant gradient surfacing layer according to claim 1 or 2, characterized in that: The preparation method of the base layer welding wire comprises the following steps: S11: Weigh Ni, Nb, Ti, CeO2, and Fe according to a set ratio, heat them in a vacuum heating furnace at 200-220°C for 1-4 hours to remove crystal water in the raw materials, and mix the heated raw materials in a powder mixer for 1-4 hours to obtain drug powder A; S12: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm; S13: After the first drawing process is completed, several drawing processes are set in sequence, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the base layer welding wire finally obtained is 1.0-1.2 mm.

4. A high temperature erosion wear resistant gradient surfacing layer according to claim 1 or 2, characterized in that: The preparation method of the cover layer welding wire comprises the following steps: S21: Weigh Cr, Ni, C, Ti, Al, La2O3, and Fe according to a set ratio, heat them in a vacuum heating furnace at 220-230°C for 2-4 hours to remove crystal water in the powder, and place the heated raw materials in a powder mixer for 1-2 hours to obtain powder B; S22: using alcohol to remove grease from the surface of the weld skin, wrapping the powder A obtained in step S11 in the weld skin through a flux-cored wire drawing device, and performing a first drawing process. The die aperture used in the first drawing process is 2.6 mm; S23: After the first drawing process is completed, several drawing processes are sequentially set, and the aperture of the drawing die corresponding to each drawing process is reduced in sequence, so that the diameter of the final cover layer welding wire is 1.0-1.2 mm.

5. The method for preparing a high-temperature erosion and wear-resistant gradient surfacing layer according to any one of claims 1 to 4, characterized in that: The following steps are involved: S31: Using a base layer welding wire to perform surfacing welding on the substrate to obtain a base layer, wherein the surfacing current is 140-160A, the surfacing layer thickness is 1.5-2.0mm, the swing width is 10-15mm, the overlap is 2-3mm, one layer is surfacing, and the shielding gas is 98%Ar+2%O2; S32: Use a cover layer welding wire to perform overlay welding on the base layer prepared in step S31 to obtain a cover layer, wherein the overlay welding current is 160-180A, the overlay welding layer thickness is 1.5-2.0mm, the swing width is 15-20mm, the overlap amount is 3-4mm, one layer is overlayed, and the shielding gas is 98%Ar+2%O2.

6. Use of the high-temperature erosion and wear-resistant gradient surfacing layer according to any one of claims 1 to 4 or the gradient surfacing layer prepared according to the preparation method of claim 5 in the heating surface of a power plant boiler.

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