Gradient surfacing layer resistant to high-temperature erosive wear as well as preparation method and application of gradient surfacing layer

Abstract

The invention discloses a gradient surfacing layer resistant to high-temperature erosive wear, which comprises a base layer and a cover surface layer, the cover surface layer is arranged above the base layer, the base layer is prepared by surfacing a base layer welding wire, and the cover surface layer is prepared by surfacing a cover surface layer welding wire; the base layer welding wire comprises powder A and a welding skin wrapping the powder A. The powder A is composed of, by mass, 70.0%-80.0% of Ni, 6%-8% of Nb, 1.0%-1.5% of Ti, 0.5%-1.0% of CeO2 and the balance Fe, and the sum of the mass percentages of the components is 100%. The covering layer welding wire comprises powder B and a welding skin wrapping the powder B. The powder B is composed of, by mass, 40.0%-50.0% of Cr, 20.0%-25.0% of Ni, 2%-4% of C, 2%-4% of Ti, 5%-8% of Al, 3%-5% of La2O3 and the balance Fe, and the sum of the mass percentages of the components is 100%. The gradient surfacing layer is suitable for surface protection of a heating surface area which is prone to erosive wear in a power plant boiler, the erosion thinning rate of the gradient surfacing layer can be effectively reduced, and therefore the service safety of a pipeline is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of welding materials, and particularly 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 life. In my country, thermal power generation is the main mode of electricity production. In 2018, my country's thermal power generation installed capacity was 1.14 billion kilowatts, accounting for about 61% of the total installed power generation capacity. It can be seen that thermal power generation plays an extremely important role in my country's electricity production. Boiler is one of the important energy conversion equipment in thermal power plants. It can convert the chemical energy in fuels such as coal, biomass or domestic waste into thermal energy of working fluids such as boiler water or steam, and then drive the steam turbine to work and drive the generator to produce electricity. When solid fuels such as coal, biomass and domestic waste are burned, in addition to the heat released by the combustion of combustible components, non-combustible components and unburned parts will still exist in the form of solid particles such as bottom ash or fly ash, and cause erosion and wear on the heating surface of the boiler.

[0003] Erosion wear refers to the material loss phenomenon caused by small solid particles impacting the material surface at a certain speed and angle. Erosion wear damage to the heating surface of power station boilers mainly occurs on the fire-facing surface. Carried by the high-temperature flue gas generated by combustion, fly ash particles will scour the heating surface, causing surface material loss and thinning of the heat exchange tube wall. Long-term scouring may even cause tube wall damage, fluid leakage, and even tube burst in severe cases, thus affecting the safe and stable operation of the boiler. Shutdowns for maintenance due to fluid leakage and tube burst caused by erosion wear account for more than 40% of the total shutdown time. Shutdowns not only affect the power supply for people's lives, but also cause huge economic losses to the power station. A single shutdown will cause hundreds of thousands or even millions of yuan in economic losses to the power station.

[0004] The Chinese patent application number CN202310697983.8 discloses a Ni-Cr welding wire resistant to high temperature hydrogen sulfide corrosion and a preparation method thereof, which relates to the technical field of welding materials 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 comprises an outer skin and a flux core filled in the outer skin; the outer skin is Cr 30 Ni 70The flux core includes 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 rest is Ni, in terms of the mass percentage of the total mass of the flux core. The Ni-Cr welding wire resistant to high temperature hydrogen sulfide corrosion provided by the invention achieves its excellent high temperature resistance through the elements of Cr, Nb, Al, and Cu, and cooperates with the CMT welding technology to obtain a surfacing layer with low dilution rate and good forming. However, the invention only uses a single surfacing layer, which may not be able to achieve high hardness and high wear resistance, and a single surfacing layer may cause large residual stresses, which may cause defects such as cracks or peeling. Therefore, it is currently urgent to design a surfacing 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 resistant to high-temperature erosion and wear, and a preparation method and application thereof, which is suitable for surface protection of heating surface areas prone to erosion and wear in power plant boilers, and can effectively reduce the erosion and thinning rate, thereby ensuring the service safety of the pipeline.

[0006] The technical solution of the present invention is 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 a base layer welding wire, and the capping layer is made by surfacing welding with a capping layer welding wire;

[0008] The base layer welding wire comprises powder A and welding skin wrapped outside 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 is Fe, and the sum of the mass percentages of the above components is 100%;

[0009] The cover layer welding wire comprises powder B and a welding skin wrapped outside the powder B, wherein 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 sizes of the medicine powder A and the medicine powder B are both 100-200 meshes.

[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 the set ratio, heat them in a vacuum heating furnace at 200-220°C to remove crystal water in the raw materials for 1-4 hours, and place the heated raw materials in a powder mixer for 1-4 hours to obtain drug powder A;

[0017] S12: removing grease from the surface of the solder skin with alcohol, wrapping the powder A obtained in step S11 in the solder skin through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 1.0-1.2mm.

[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 the set ratio, heat them in a vacuum heating furnace at 220-230°C to remove crystal water in the powder for 2-4 hours, and place the heated raw materials in a powder mixer for 1-2 hours to obtain powder B;

[0021] S22: removing grease from the surface of the solder paste with alcohol, wrapping the powder A obtained in step S11 in the solder paste through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 cap layer welding wire finally obtained is 1.0-1.2mm.

[0023] The 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 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, surfacing is 1 layer, and the protective gas is 98%Ar+2%O2;

[0025] S32: Use a cap layer welding wire to perform overlay welding on the base layer obtained in step S31 to obtain a cap 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, 1 layer is overlay welded, and the protective gas is 98% Ar+2% O2.

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

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

[0028] 1. The present invention provides a gradient surfacing layer that is resistant to high-temperature erosion and wear. Aiming at the harsh service conditions inside the boiler, a gradient surfacing layer is designed, wherein the base layer is mainly made of Fe-Ni-Nb alloy system, which has good toughness and can ensure excellent metallurgical bonding strength and excellent plastic toughness between the heated surface tube; the cover layer is mainly made of Fe-Cr-Ni-Al alloy system, which can effectively reduce the ash flying erosion and thinning speed under high temperature and ensure high-temperature erosion resistance. The present invention adopts this gradient structure, which has better high-temperature service performance than a single surfacing layer structure.

[0029] 2. A large amount of Ni element is added to the base layer welding wire of the present invention. On the premise of ensuring that the base layer has high temperature performance, the bonding strength between the base layer and the pipeline substrate can be guaranteed, and the Nb element is added to further improve the stability of the base layer at high temperatures. A small amount of rare earth CeO2 is also added to the base layer welding wire. The rare earth oxide has the function of purifying the grain boundary and improving the grain boundary bonding strength, further improving the bonding strength 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 guarantee the high temperature performance of the cover weld, Al element can further improve the high temperature oxidation resistance of the cover weld, C and Ti elements have a solid solution strengthening effect on the one hand, and can generate TiC in situ on the other hand, which plays a role in pinning grain boundaries, refining grains, and improving the high temperature stability of the cover layer, and La2O3 plays a role in further purifying the grain boundaries.

[0031] 4. The gradient cladding 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 cladding layer of Example 2 of the present invention;

[0033] Figure 2 The metallographic structure of the capping layer of the cladding 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] The following is in conjunction with the preferred embodiment and with reference to the attached Figure 1-3 , the present invention is further described. 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 high-temperature erosion and wear-resistant gradient surfacing layer, 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 a base layer welding wire, and the capping layer is made by surfacing welding with a capping layer welding wire;

[0038] The base layer welding wire comprises powder A and welding skin wrapped outside the powder A, wherein the powder 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 comprises powder B and welding skin wrapped outside the powder B, wherein 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 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 comprises the following steps:

[0042] S11: Weigh Ni, Nb, Ti, CeO2 and Fe according to the set ratio, heat them in a vacuum heating furnace at 200°C to remove crystal water in the raw materials for 1 hour, and place the heated raw materials in a powder mixer for 1 hour to obtain drug powder A;

[0043] S12: removing grease from the surface of the solder skin with alcohol, wrapping the powder A obtained in step S11 in the solder skin through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 mm.

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

[0046] S21: Weigh Cr, Ni, C, Ti, Al, La2O3 and Fe according to the set ratio, heat them in a vacuum heating furnace at 220°C to remove crystal water in the powder for 2 hours, and place the heated raw materials in a powder mixer for 1 hour to obtain powder B;

[0047] S22: removing grease from the surface of the solder paste with alcohol, wrapping the powder A obtained in step S11 in the solder paste through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 cap layer welding wire finally obtained 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 to perform cladding welding on the surface of 12Cr1MoV to obtain a base layer, wherein the cladding current is 140A, the cladding layer thickness is 1.5mm, the swing width is 10mm, the overlap amount is 2mm, cladding is 1 layer, and the shielding gas is 98%Ar+2%O2;

[0051] S32: Use the cap layer welding wire to perform overlay welding on the base layer obtained in step S31 to obtain a cap 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 high-temperature erosion and wear-resistant gradient surfacing layer, 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 a base layer welding wire, and the capping layer is made by surfacing welding with a capping layer welding wire;

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

[0055] The cover layer welding wire comprises powder B and welding skin wrapped outside the powder B, wherein the powder B is composed of the following components in mass percentage: Cr 50.0%, Ni 25.0%, C 4%, Ti 4%, Al 8%, La2O3 5%, and the rest is 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 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 comprises the following steps:

[0058] S11: Weigh Ni, Nb, Ti, CeO2 and Fe according to the set ratio, heat them in a vacuum heating furnace at 220°C to remove crystal water in the raw materials for 4 hours, and place the heated raw materials in a powder mixer for 4 hours to obtain powder A;

[0059] S12: removing grease from the surface of the solder skin with alcohol, wrapping the powder A obtained in step S11 in the solder skin through a flux-cored wire drawing device, and performing a first drawing process, wherein 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, 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 1.2 mm.

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

[0062] S21: Weigh Cr, Ni, C, Ti, Al, La2O3 and Fe according to the set ratio, heat them in a vacuum heating furnace at 230°C to remove crystal water in the powder for 4 hours, and place the heated raw materials in a powder mixer for 2 hours to obtain powder B;

[0063] S22: removing grease from the surface of the solder paste with alcohol, wrapping the powder A obtained in step S11 in the solder paste through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 cap layer welding wire finally obtained 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 to perform cladding welding on the surface of 12Cr1MoV to obtain a base layer, wherein the cladding current is 160A, the cladding layer thickness is 2.0mm, the swing width is 15mm, the overlap amount is 3mm, cladding is 1 layer, and the shielding gas is 98%Ar+2%O2;

[0067] S32: Use the cap layer welding wire to perform overlay welding on the base layer obtained in step S31 to obtain a cap 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 overlay welded, and the shielding gas is 98% Ar+2% O2.

[0068] Example 3

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

[0070] The base layer welding wire comprises powder A and welding skin wrapped outside the powder A, wherein the powder 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 comprises powder B and welding skin wrapped outside the powder B, wherein 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 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 comprises the following steps:

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

[0075] S12: removing grease from the surface of the solder skin with alcohol, wrapping the powder A obtained in step S11 in the solder skin through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 1.1 mm.

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

[0078] S21: Cr, Ni, C, Ti, Al, La2O3 and Fe are weighed according to the set ratio, placed in a vacuum heating furnace at 210°C for heating to remove crystal water in the powder, the heating time is 3 hours, and the heated raw materials are placed in a powder mixer for mixing for 1.5 hours to obtain powder B;

[0079] S22: removing grease from the surface of the solder paste with alcohol, wrapping the powder A obtained in step S11 in the solder paste through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 cap layer welding wire finally obtained 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 to perform cladding welding on the surface of 12Cr1MoV to obtain a base layer, wherein the cladding current is 150A, the cladding layer thickness is 1.7mm, the swing width is 13mm, the overlap is 2.5mm, cladding is 1 layer, and the protective gas is 98%Ar+2%O2;

[0083] S32: Use the cap layer welding wire to perform overlay welding on the base layer obtained in step S31 to obtain a cap 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 high-temperature erosion and wear-resistant gradient surfacing layer, 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 a base layer welding wire, and the capping layer is made by surfacing welding with a capping layer welding wire;

[0086] The base layer welding wire comprises powder A and welding skin wrapped outside the powder A, wherein the powder 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 is Fe, and the sum of the mass percentages of the above components is 100%;

[0087] The cover layer welding wire comprises powder B and welding skin wrapped outside the powder B, wherein 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, and 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 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 comprises the following steps:

[0090] S11: Weigh Ni, Nb, Ti, CeO2 and Fe according to the set ratio, heat them in a vacuum heating furnace at 215°C to remove crystal water in the raw materials for 1.4 hours, and mix the heated raw materials in a powder mixer for 1.4 hours to obtain drug powder A;

[0091] S12: removing grease from the surface of the solder skin with alcohol, wrapping the powder A obtained in step S11 in the solder skin through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 1.1 mm.

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

[0094] S21: Cr, Ni, C, Ti, Al, La2O3 and Fe are weighed respectively according to the set ratio, and placed in a vacuum heating furnace at 222°C for heating to remove the crystal water in the powder. The heating time is 2.4 hours, and the heated raw materials are placed in a powder mixer for mixing for 1.2 hours to obtain powder B;

[0095] S22: removing grease from the surface of the solder paste with alcohol, wrapping the powder A obtained in step S11 in the solder paste through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 cap layer welding wire finally obtained 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 to perform cladding welding on the surface of 12Cr1MoV to obtain a base layer, wherein the cladding current is 150A, the cladding layer thickness is 1.8mm, the swing width is 12mm, the overlap amount is 2.3mm, cladding is 1 layer, and the protective gas is 98%Ar+2%O2;

[0099] S32: Use the cap layer welding wire to perform overlay welding on the base layer obtained in step S31 to obtain a cap 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 high-temperature erosion and wear-resistant gradient surfacing layer, 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 a base layer welding wire, and the capping layer is made by surfacing welding with a capping layer welding wire;

[0102] The base layer welding wire comprises powder A and welding skin wrapped outside the powder A, wherein the powder 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 comprises powder B and a welding skin wrapped outside the powder B, wherein 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, and 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 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 comprises the following steps:

[0106] S11: Weigh Ni, Nb, Ti, CeO2 and Fe according to the set ratio, heat them in a vacuum heating furnace at 218°C to remove crystal water in the raw materials for 3 hours, and place the heated raw materials in a powder mixer for 3 hours to obtain powder A;

[0107] S12: removing grease from the surface of the solder skin with alcohol, wrapping the powder A obtained in step S11 in the solder skin through a flux-cored wire drawing device, and performing a first drawing process, wherein 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, 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 1.2 mm.

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

[0110] S21: Cr, Ni, C, Ti, Al, La2O3 and Fe were weighed according to the set ratio, and placed in a vacuum heating furnace at 229°C for heating to remove crystal water in the powder. The heating time was 3.8 hours, and the heated raw materials were placed in a powder mixer for mixing for 1.1 hours to obtain powder B;

[0111] S22: removing grease from the surface of the solder paste with alcohol, wrapping the powder A obtained in step S11 in the solder paste through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 cap layer welding wire finally obtained 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 to perform cladding welding on the surface of 12Cr1MoV to obtain a base layer, wherein the cladding current is 150A, the cladding layer thickness is 1.9mm, the swing width is 14mm, the overlap amount is 2.6mm, cladding is 1 layer, and the shielding gas is 98%Ar+2%O2;

[0115] S32: Use the cap layer welding wire to perform overlay welding on the base layer obtained in step S31 to obtain a cap 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 cladding layer of this comparative example does not include a base layer, and the cap layer welding wire of this comparative example is directly clad 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 of ERNiCrMo-3 welding wire, which is composed of the following components in mass percentage: Cr 22.18%, Nb 3.76%, Mo 9.27%, Fe 0.1%, 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 of ERNiCrCoMo-1 welding wire, which is composed of the following components in mass percentage: Cr 22.92%, Co 12.08%, Mo 9.12%, Fe 0.43%, and the balance Ni.

[0124] Implementation effect evaluation

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

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

[0127] Table 1 Statistical table of weld overlay performance test results

[0128]

[0129]

[0130] It can be seen from the above table that the gradient surfacing layer provided by the present invention has very high hardness and bonding strength, can effectively reduce the ash flying erosion thinning rate under high temperature, and ensures 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 capping layer of the cladding layer in Example 2. Figure 2 It can be seen that the cover layer structure is mainly 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 result of the high temperature erosion morphology of the cladding layer in Example 2. 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 temperature.

[0134] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all belong to the protection scope 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 capping layer, wherein the capping layer is arranged above the base layer, the base layer is made by surfacing welding of the base layer welding wire, and the capping layer is made by surfacing welding of the capping layer welding wire; The base layer welding wire comprises powder A and welding skin wrapped outside 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 is Fe, and the sum of the mass percentages of the above components is 100%; The cover layer welding wire comprises powder B and a welding skin wrapped outside the powder B, wherein 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%.

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

3. The high temperature erosion and wear resistant gradient surfacing layer according to claim 1, characterized in that: The material of the welding skin in the base layer welding wire and the cover layer welding wire is 430 steel strip.

4. The high temperature erosion and wear resistant gradient surfacing layer according to claim 1, characterized in that: 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.

5. The high temperature erosion and wear resistant gradient surfacing layer according to claim 1, characterized in that: The filling rate of the powder A in the base layer welding wire is 20-22%.

6. The high temperature erosion and wear resistant gradient surfacing layer according to claim 1, characterized in that: The filling rate of the powder B in the cover layer welding wire is 18-20%.

7. A high temperature erosion and wear resistant gradient surfacing layer according to any one of claims 1 to 6, 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 the set ratio, heat them in a vacuum heating furnace at 200-220°C to remove crystal water in the raw materials for 1-4 hours, and place the heated raw materials in a powder mixer for 1-4 hours to obtain drug powder A; S12: removing grease from the surface of the solder skin with alcohol, wrapping the powder A obtained in step S11 in the solder skin through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 1.0-1.2mm.

8. A high temperature erosion and wear resistant gradient surfacing layer according to any one of claims 1 to 6, characterized in that: The method for preparing the cap layer welding wire comprises the following steps: S21: Weigh Cr, Ni, C, Ti, Al, La2O3 and Fe according to the set ratio, heat them in a vacuum heating furnace at 220-230°C to remove crystal water in the powder for 2-4 hours, and place the heated raw materials in a powder mixer for 1-2 hours to obtain powder B; S22: removing grease from the surface of the solder paste with alcohol, wrapping the powder A obtained in step S11 in the solder paste through a flux-cored wire drawing device, and performing a first drawing process, wherein 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 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 cap layer welding wire finally obtained is 1.0-1.2mm.

9. The method for preparing a high temperature erosion and wear resistant gradient cladding layer according to any one of claims 1 to 8, 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, surfacing is 1 layer, and the protective gas is 98%Ar+2%O2; S32: Use a cap layer welding wire to perform overlay welding on the base layer obtained in step S31 to obtain a cap 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, 1 layer is overlay welded, and the protective gas is 98% Ar+2% O2.

10. Use of a high-temperature erosion and wear resistant gradient cladding layer according to any one of claims 1 to 8 or a gradient cladding layer prepared by the preparation method according to claim 9 in the heating surface of a boiler in a power plant.

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