Processing technology of self-fluxing alloy repairing powder

Abstract

The invention provides a processing technology of self-fluxing alloy repairing powder. The self-fluxing alloy repairing powder comprises 0.25%-0.35% of C, 0.80%-1.20% of Si, 0.20%-0.50% of Mn, 4.50%-5.50% of Cr, 1.00%-1.50% of Mo, 0.80%-1.20% of V, 0.05%-0.15% of Nb, 0.02%-0.08% of Ti, 0.05%-0.15% of Ce, smaller than or equal to 0.005% of P, smaller than or equal to 0.005% of S and the balance Fe. The processing steps comprise double refining processes of electroslag remelting and vacuum induction melting, so that deep desulfurization, dephosphorization and boron removal can be realized; waste H13 die steel is adopted as a raw material, waste is turned into wealth, through three core technical means of ultralow P and S content, no B and proper addition of Nb, Ti and Ce, the advantages of high hardness of a cladding layer, high bonding strength of the cladding layer and the H13 die steel, ultra-long thermal fatigue life, low porosity and low crack density in the subsequent repairing stage are achieved, and the performance of the repaired H13 die steel is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaics, and in particular to a processing technology of self-fluxing alloy repair powder. Background Art

[0002] Photovoltaic aluminum profiles are important materials for photovoltaic brackets and structural parts. Their manufacturing process needs to withstand harsh environments such as high temperature, high pressure and corrosion. In order to ensure the production efficiency and long-term stability of photovoltaic aluminum profiles, the wear resistance and high temperature resistance of H13 mold steel become key factors. In the manufacturing of photovoltaic aluminum profiles, H13 mold steel, as the core mold material, is subjected to high temperature, high pressure and corrosive media for a long time, and is prone to performance degradation due to thermal fatigue, oxidation wear and surface cracks. According to statistics, the direct economic losses caused by mold failure in the photovoltaic industry exceed 1 billion yuan each year.

[0003] In order to reduce production costs, this case attempts to recycle waste H13 mold steel to prepare self-fluxing alloy repair powder. However, phosphorus (P), sulfur (S), and boron (B) elements are enriched in waste H13 mold steel. Phosphorus (P) and sulfur (S) are common harmful impurities that will reduce the impact toughness of H13 mold steel, increase hot brittleness and crack sensitivity. H13 mold steel is prone to thermal fatigue cracks in high-temperature service environments, shortening the life of the mold; Boron (B) is easy to form brittle compounds with Fe and Cr at high temperatures, resulting in a sharp decrease in the thermal shock stability of the repair layer and the precipitation of brittle phases, reducing the thermal fatigue resistance of H13 mold steel. In addition, the existing technology mostly relies on a single vacuum melting steel ingot process to prepare H13 mold steel repair powder. The prepared repair powder has high phosphorus (P) and sulfur (S) content, and it is difficult to efficiently remove the boron (B) element.

[0004] In view of this, the inventor of this case conducted in-depth research on the above-mentioned issues, which led to the emergence of this case. Summary of the invention

[0005] The present invention aims to solve the shortcomings of H13 die steel repair metal powder in the prior art, and provides a processing technology for self-fluxing alloy repair powder. Waste H13 die steel is used as a raw material to turn waste into treasure, and deep desulfurization, dephosphorization and deboronization can be carried out through a double refining process of electroslag remelting and vacuum induction melting to obtain a self-fluxing alloy repair powder with low P and S content, containing Nb, Ti, Ce elements, and no B element.

[0006] The present invention is achieved as follows: a processing technology for a self-fluxing alloy repair powder, the self-fluxing alloy repair powder comprising 0.25-0.35% C, 0.80-1.20% Si, 0.20-0.50% Mn, 4.50-5.50% Cr, 1.00-1.50% Mo, 0.80-1.20% V, 0.05-0.15% Nb, 0.02-0.08% Ti, 0.05-0.15% Ce, P≤0.005%, S≤0.005%, and the balance is Fe.

[0007] Furthermore, the self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; Step 2: Electroslag remelting: The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and unnecessary impurities are refined and removed; the liquid metal is cooled and solidified in the furnace to form an ingot; Step 3: Vacuum induction melting: The steel ingot is induction melted in a vacuum environment, and an induction current is used to heat the steel ingot to a molten state. After the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain alloy liquid; the alloy liquid is atomized into fine droplets, and the air flow quickly cools the droplets to form fine metal powder particles; the metal powder particles are collected to obtain uniform self-fluxing alloy repair powder.

[0008] Furthermore, in step 1, the raw material is cut into blocks with a size of 50-100 mm.

[0009] Furthermore, in step 2, the refining temperature is controlled at 1600-1650°C, and the refining time is 2-2.5h.

[0010] Furthermore, in step 2, the slag system ratio in the electroslag remelting furnace is 55-58% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 12-15% magnesium oxide.

[0011] Furthermore, in step 2, the metal liquid is cooled in the furnace by gradient cooling, first air-cooling to 800°C, and then water-cooling to room temperature to form a steel ingot.

[0012] Furthermore, in step 3, the alloy liquid is atomized into fine droplets using an argon-nitrogen mixed gas, with the ratio of argon to nitrogen being 4:1; during atomization, the oxygen content is ≤200ppm.

[0013] Furthermore, in step 4, the self-fluxing alloy repair powder has a particle size of 60-90 μm, a D50 median particle size of 65-80 μm, a fluidity of >25s / 50g, and a sphericity of ≥95%.

[0014] Furthermore, the self-fluxing alloy repair powder includes 0.3% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.05% Ti, 0.1% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70 μm.

[0015] Furthermore, the self-fluxing alloy repair powder includes 0.25% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.05% Ti, 0.15% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70 μm.

[0016] The advantages of the present invention are: 1. The particle size of the self-fluxing alloy repair powder is 60-90μm, the D50 median particle size is 65-80μm, the fluidity>25s / 50g, and the sphericity ≥95%; the powder particle size of 60-90μm can affect the quality of the subsequent repair cladding layer. Too large a particle size will affect the melting of the powder, and too small a particle size will easily oxidize or fly away; the fluidity>25s / 50g makes the powder flow well, which is conducive to uniform powder feeding; the sphericity ≥95% is conducive to the powder flow and melting effect.

[0017] 2. The processing technology of the self-fluxing alloy repair powder of the present invention adopts discarded H13 mold steel as raw material, turning waste into treasure, and cooperates with the dual refining process of electroslag remelting (ESR) + vacuum induction melting (VIM) to achieve deep desulfurization, dephosphorization and deboronization; through the three core technical means of ultra-low P and S content, no B, and appropriate addition of Nb, Ti, and Ce, the advantages of high hardness of the cladding layer in the subsequent repair stage, high bonding strength with H13 mold steel, ultra-long thermal fatigue life, low porosity and low crack density are achieved, and the performance of the H13 mold steel after repair is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0019] Figure 1 It is a schematic structural diagram of the self-fluxing alloy repair powder obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0020] In order to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0021] See also Figure 1As shown, the present invention provides a processing technology for self-fluxing alloy repair powder, wherein the self-fluxing alloy repair powder includes 0.25-0.35% C, 0.80-1.20% Si, 0.20-0.50% Mn, 4.50-5.50% Cr, 1.00-1.50% Mo, 0.80-1.20% V, 0.05-0.15% Nb, 0.02-0.08% Ti, 0.05-0.15% Ce, P≤0.005%, S≤0.005%, and the balance is Fe. The particle size of the self-fluxing alloy repair powder is 60-90 μm, the D50 median particle size is 65-80 μm, the fluidity is>25s / 50g, and the sphericity is ≥95%. The powder particle size of 60-90μm can affect the quality of the subsequent repair cladding layer. Too large a particle size will affect the melting of the powder, while too small a particle size will easily oxidize or scatter. The fluidity>25s / 50g makes the powder flow well and helps to feed the powder evenly. The sphericity ≥95% helps the powder flow and melting effect.

[0022] The self-fluxing alloy repair powder comprises the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and unnecessary impurities such as S, P, and B are refined and removed; the liquid metal is cooled and solidified in the furnace to form an ingot; Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain alloy liquid; the alloy liquid is atomized into fine droplets, and the airflow quickly cools the droplets to form fine metal powder particles; the metal powder particles are collected to obtain uniform self-fluxing alloy repair powder. Adding Ti first can prevent oxidation, then adding Nb, and finally adding Ce to avoid Ce reacting preferentially with oxygen.

[0023] The processing technology of the self-fluxing alloy repair powder of the present invention adopts discarded H13 die steel as raw material, turning waste into treasure, and cooperates with the dual refining process of electroslag remelting (ESR) + vacuum induction melting (VIM) to achieve deep desulfurization, dephosphorization and deboronization; through the three core technical means of ultra-low P and S content, no B, and appropriate addition of Nb, Ti, and Ce, the advantages of high hardness of the cladding layer in the subsequent repair stage, high bonding strength with H13 die steel, ultra-long thermal fatigue life, low porosity and low crack density are achieved, and the performance of the H13 die steel after repair is significantly improved.

[0024] In step 1 of the present invention, the raw material is cut into blocks of 50-100 mm in size. If the size is too small (<50 mm), oxidation may be aggravated, and if the size is too large (>100 mm), the melting efficiency and uniformity of electroslag remelting may be affected.

[0025] In step 2 of the present invention, the refining temperature is controlled at 1600-1650°C, and the refining time is 2-2.5 hours. This temperature range can effectively remove P and S impurities, 1600-1650°C is close to the volatilization temperature of boron oxide, and the refining time is extended to 2-2.5 hours, which promotes the oxidation of boron and adsorption of slag phase, and the boron content can be controlled at ≤0.001%, meeting the boron-free (B) requirement.

[0026] In step 2 of the present invention, the slag system ratio in the electroslag remelting furnace is 55-58% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 12-15% magnesium oxide. Calcium fluoride is the leading desulfurization, and the desulfurization efficiency can be improved by forming calcium sulfide into the slag phase; aluminum oxide enhances the stability of the slag system; calcium oxide is used to assist in dephosphorization, and magnesium oxide and boron oxide in the raw material generate stable magnesium borate to achieve deep deboronization. The higher the proportion of magnesium oxide, the better the deboronization effect.

[0027] In step 2 of the present invention, the metal liquid is cooled in the furnace by gradient cooling, first air-cooled to 800°C, and then water-cooled to room temperature to form a steel ingot. The gradient cooling of the steel ingot can avoid internal stress cracks.

[0028] In step 3 of the present invention, the alloy liquid is atomized into fine droplets using an argon-nitrogen mixed gas, with the ratio of argon to nitrogen being 4:1; during atomization, the oxygen content is ≤200 ppm to ensure the atomization quality.

[0029] The present invention also provides a repair process for H13 die steel, comprising the following steps: Step 1: Clean and decontaminate the surface of the H13 mold steel to be repaired, anneal at 650℃ for 2h, and preheat. The preheating temperature is 400-500℃, and an infrared thermometer is used for real-time monitoring. Preheating treatment avoids thermal cracks caused by excessive temperature difference. The melting point of H13 mold steel is about 850℃, and preheating below 300℃ is not enough to eliminate thermal stress. Annealing at 650℃ eliminates residual stress, and preheating at 400-500℃ avoids thermal stress, which is in line with the heat treatment characteristics of H13 mold steel.

[0030] Step 2: Use a fiber laser cladding system for cladding, adjust the parameters of the fiber laser cladding system, laser power is 800-1200W, spot diameter is 1.5-2.0mm, laser scanning rate is 6-8mm / s, powder feeding rate is 5-8g / min, layer thickness is 0.2-1.0mm, overlap rate is 30-50%, and focus position is 0-1mm; feed the self-fluxing alloy repair powder into the laser action area of ​​the fiber laser cladding system; during the laser scanning process, the laser beam heats the local area to a molten alloy liquid. The laser power is set at 800-1200W for fine repair; the spot diameter is set at 1.5-2.0mm for high-precision repair; the powder feeding rate is 5-8g / min. Too low a powder feeding rate affects the cladding efficiency, while too high a powder feeding rate can easily lead to powder accumulation or inclusions; the laser scanning rate is 6-8mm / s for fine cladding; the overlap rate is 30-50% to ensure that the cladding layer is uniform and has no obvious gaps; the focus position is 0-1mm to control the cladding depth.

[0031] Step 3: The alloy liquid is sent to the surface of the H13 mold steel to be repaired, and the laser beam and the alloy liquid interact to form a solid cladding layer; the cladding is carried out by layer-by-layer stacking method, and the thickness of each cladding layer is controlled at 0.2-1.0mm to ensure good cladding bonding and surface flatness; during this period, protective gas is introduced to help the self-fluxing alloy repair powder flow and avoid oxidation.

[0032] Step 4: After stress relief annealing at 550℃ for 2h, the cladding layer is cryogenically treated, and trimmed and polished using a high-precision CNC grinder; the repair is completed.

[0033] The photovoltaic aluminum profile H13 mold steel obtained by this repair method has a cladding layer with a hardness of 720±20HV, a porosity of <1%, basically no cracks, and a service life extended by 150-200%.

[0034] Several experimental groups and comparative groups are used below to illustrate the beneficial technical effects of the processing technology of the self-fluxing alloy repair powder of the present invention.

[0035] Experimental Group 1 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0036] Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and then refined to remove unnecessary impurities; the liquid metal is cooled by gradient cooling in the furnace, first air-cooled to 800°C, and then water-cooled to room temperature to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining time is 2.5 hours. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 15% magnesium oxide.

[0037] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain alloy liquid; the alloy liquid is atomized into fine droplets, and the airflow quickly cools the droplets to form fine metal powder particles; the metal powder particles are collected to obtain uniform self-fluxing alloy repair powder. The alloy liquid is atomized into fine droplets using an argon-nitrogen mixed gas with a ratio of 4:1; during atomization, the oxygen content is ≤200ppm.

[0038] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.3% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.05% Ti, 0.1% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70μm, the D50 median particle size is 70μm, the fluidity is>25s / 50g, and the sphericity is ≥95%.

[0039] Experimental Group 2 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0040] Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and then refined to remove unnecessary impurities; the liquid metal is cooled by gradient cooling in the furnace, first air-cooled to 800°C, and then water-cooled to room temperature to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining time is 2.5 hours. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 15% magnesium oxide.

[0041] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain alloy liquid; the alloy liquid is atomized into fine droplets, and the airflow quickly cools the droplets to form fine metal powder particles; the metal powder particles are collected to obtain uniform self-fluxing alloy repair powder. The alloy liquid is atomized into fine droplets using an argon-nitrogen mixed gas with a ratio of 4:1; during atomization, the oxygen content is ≤200ppm.

[0042] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.25% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.05% Ti, 0.15% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70μm, the D50 median particle size is 70μm, the fluidity is>25s / 50g, and the sphericity is ≥95%.

[0043] Experimental Group 3 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0044] Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and then refined to remove unnecessary impurities; the liquid metal is cooled by gradient cooling in the furnace, first air-cooled to 800°C, and then water-cooled to room temperature to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining time is 2.5 hours. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 15% magnesium oxide.

[0045] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain alloy liquid; the alloy liquid is atomized into fine droplets, and the airflow quickly cools the droplets to form fine metal powder particles; the metal powder particles are collected to obtain uniform self-fluxing alloy repair powder. The alloy liquid is atomized into fine droplets using an argon-nitrogen mixed gas with a ratio of 4:1; during atomization, the oxygen content is ≤200ppm.

[0046] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.35% C, 0.8% Si, 0.5% Mn, 4.5% Cr, 1.50% Mo, 0.8% V, 0.05% Nb, 0.08% Ti, 0.05% Ce, P≤0.005%, S≤0.005%, and the balance is Fe. The particle size of the self-fluxing alloy repair powder is 70 μm, the D50 median particle size is 70 μm, the fluidity is >25s / 50g, and the sphericity is ≥95%.

[0047] Experimental Group 4 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0048] Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and then refined to remove unnecessary impurities; the liquid metal is cooled by gradient cooling in the furnace, first air-cooled to 800°C, and then water-cooled to room temperature to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining time is 2.5 hours. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 15% magnesium oxide.

[0049] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain alloy liquid; the alloy liquid is atomized into fine droplets, and the airflow quickly cools the droplets to form fine metal powder particles; the metal powder particles are collected to obtain uniform self-fluxing alloy repair powder. The alloy liquid is atomized into fine droplets using an argon-nitrogen mixed gas with a ratio of 4:1; during atomization, the oxygen content is ≤200ppm.

[0050] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.3% C, 1.0% Si, 0.2% Mn, 5.0% Cr, 1.0% Mo, 1.2% V, 0.15% Nb, 0.05% Ti, 0.1% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 65μm, the D50 median particle size is 65μm, the fluidity is>25s / 50g, and the sphericity is ≥95%.

[0051] Comparison group 1 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0052] Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and then refined to remove unnecessary impurities; the liquid metal is cooled by gradient cooling in the furnace, first air-cooled to 800°C, and then water-cooled to room temperature to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining time is 2.5 hours. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 15% magnesium oxide.

[0053] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, adding an appropriate amount of Ce to obtain alloy liquid; atomizing the alloy liquid into fine droplets, the airflow quickly cools the droplets to form fine metal powder particles; collecting the metal powder particles to obtain uniform self-fluxing alloy repair powder. Use argon-nitrogen mixed gas to atomize the alloy liquid into fine droplets, with an argon-nitrogen ratio of 4:1; during atomization, the oxygen content is ≤200ppm.

[0054] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.3% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70μm, the D50 median particle size is 70μm, the fluidity is>25s / 50g, and the sphericity is ≥95%.

[0055] Comparison group 2 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0056] Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and then refined to remove unnecessary impurities; the liquid metal is cooled by gradient cooling in the furnace, first air-cooled to 800°C, and then water-cooled to room temperature to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining time is 2.5 hours. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 15% magnesium oxide.

[0057] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, adding appropriate amounts of Ti and Nb in batches to obtain alloy liquid; atomizing the alloy liquid into fine droplets, the airflow rapidly cools the droplets to form fine metal powder particles; collecting the metal powder particles to obtain uniform self-fluxing alloy repair powder. Use argon-nitrogen mixed gas to atomize the alloy liquid into fine droplets, with an argon-nitrogen ratio of 4:1; during atomization, the oxygen content is ≤200ppm.

[0058] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.3% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.05% Ti, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70μm, the D50 median particle size is 70μm, the fluidity is>25s / 50g, and the sphericity is ≥95%.

[0059] Comparison group 3 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0060] Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and then refined to remove unnecessary impurities; the liquid metal is cooled by gradient cooling in the furnace, first air-cooled to 800°C, and then water-cooled to room temperature to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining time is 2.5 hours. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 15% magnesium oxide.

[0061] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, adding appropriate amounts of Ti, excess Nb, and appropriate amounts of Ce in batches to obtain alloy liquid; atomizing the alloy liquid into fine droplets, and rapidly cooling the droplets with airflow to form fine metal powder particles; collecting the metal powder particles to obtain uniform self-fluxing alloy repair powder. Using argon-nitrogen mixed gas to atomize the alloy liquid into fine droplets, the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content is ≤200ppm.

[0062] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.3% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.25% Nb, 0.08% Ti, 0.1% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70μm, the D50 median particle size is 70μm, the fluidity is>25s / 50g, and the sphericity is ≥95%.

[0063] Comparison group 4 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0064] Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and then refined to remove unnecessary impurities; the liquid metal is cooled by gradient cooling in the furnace, first air-cooled to 800°C, and then water-cooled to room temperature to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining time is 2.5 hours. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 15% magnesium oxide.

[0065] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, adding excess Ti, appropriate amount of Nb, and appropriate amount of Ce in batches to obtain alloy liquid; atomizing the alloy liquid into fine droplets, the airflow quickly cools the droplets to form fine metal powder particles; collecting the metal powder particles to obtain uniform self-fluxing alloy repair powder. Use argon-nitrogen mixed gas to atomize the alloy liquid into fine droplets, with an argon-nitrogen ratio of 4:1; during atomization, the oxygen content is ≤200ppm.

[0066] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.3% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.15% Ti, 0.1% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70μm, the D50 median particle size is 70μm, the fluidity is>25s / 50g, and the sphericity is ≥95%.

[0067] Comparison group 5 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0068] Step 2: The raw materials are put into the furnace to melt into liquid metal; the liquid metal is cooled in the furnace by gradient cooling, first air-cooled to 800°C, and then water-cooled to room temperature to form a steel ingot.

[0069] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain alloy liquid; the alloy liquid is atomized into fine droplets, and the airflow quickly cools the droplets to form fine metal powder particles; the metal powder particles are collected to obtain uniform self-fluxing alloy repair powder. The alloy liquid is atomized into fine droplets using an argon-nitrogen mixed gas with a ratio of 4:1; during atomization, the oxygen content is ≤200ppm.

[0070] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.3% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.05% Ti, 0.02% P, 0.02% S, 0.1% B, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70 μm, the D50 median particle size is 70 μm, the fluidity is >25s / 50g, and the sphericity is ≥95%.

[0071] Comparison group 6 A self-fluxing alloy repair powder includes the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; the raw material cutting size is 100mm block.

[0072] Step 2: Electroslag remelting (ESR): The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into metal liquid, and unnecessary impurities are refined; the metal liquid is cooled by gradient cooling in the furnace, first air-cooled to 800°C, and then water-cooled to room temperature to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining time is 2.5h. The slag system ratio in the electroslag remelting furnace is 70% calcium fluoride, 20% aluminum oxide, and 10% calcium oxide.

[0073] Step 3: Vacuum Induction Melting (VIM): Induction melting of steel ingots in a vacuum environment, using induction current to heat the steel ingots to a molten state, after the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain alloy liquid; the alloy liquid is atomized into fine droplets, and the airflow quickly cools the droplets to form fine metal powder particles; the metal powder particles are collected to obtain uniform self-fluxing alloy repair powder. The alloy liquid is atomized into fine droplets using an argon-nitrogen mixed gas with a ratio of 4:1; during atomization, the oxygen content is ≤200ppm.

[0074] The self-fluxing alloy repair powder is quality tested to check its composition, particle size distribution, fluidity and other indicators. The self-fluxing alloy repair powder includes 0.3% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.05% Ti, 0.1% Ce, P≤0.005%, S≤0.005%, 0.1% B, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70μm, the D50 median particle size is 70μm, the fluidity is>25s / 50g, and the sphericity is ≥95%.

[0075] The self-fluxing alloy repair powders prepared in the experimental groups 1-4 and the comparative groups 1-6 were applied to the repair process of the H13 die steel of the present invention, and various performance indicators of the repaired H13 die steel were tested.

[0076]

[0077] in conclusion: 1. The self-fluxing alloy repair powder prepared by the implementation groups 1-4 controls the contents of Nb (0.05-0.15%), Ti (0.02-0.08%), and Ce (0.05-0.15%), and strictly limits P and S to ≤ 0.005%, and does not contain B, thereby achieving the advantages of high hardness, high bonding strength, ultra-long thermal fatigue life, low porosity, and low crack density of the H13 die steel cladding layer, and significantly improving the performance of the repaired H13 die steel.

[0078] 2. The slag system ratio of the electroslag remelting process (ESR) of the implementation group 1-4 combined with the refining temperature of 1650°C and the refining time of 2.5h achieved deep desulfurization (S≤0.005%), dephosphorization (P≤0.005%) and deboronization (B≤0.001%). The B residue (0.1%) of the comparison group 5 (ESR without electroslag remelting) and the comparison group 6 (slag system without magnesium oxide) resulted in a thermal fatigue life of only 1 / 3 of that of the experimental group.

[0079] 3. The vacuum induction melting (VIM) process of groups 1-4 was implemented, combined with the batch addition of Ti, Nb, and Ce to ensure the uniform distribution of micro-alloy elements; the hardness, bonding strength, and crack density of comparison group 1 (without Nb and Ti) and comparison group 2 (without Ce) were significantly reduced; brittle phases were generated in comparison group 3 (Nb excess to 0.25%) and comparison group 4 (Ti excess to 0.15%), and the performance was significantly reduced.

[0080] 4. The P and S contents of implementation groups 1-4 ≤ 0.005% significantly reduced brittleness, and the complete removal of B (≤ 0.001%) avoided thermal fatigue cracks. The crack density (8.7 / mm²) and porosity (2.1%) of comparison group 5 (P, S, B residues) far exceeded those of the experimental group.

[0081] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A processing technology for self-fluxing alloy repair powder, characterized in that: The self-fluxing alloy repair powder comprises 0.25-0.35% C, 0.80-1.20% Si, 0.20-0.50% Mn, 4.50-5.50% Cr, 1.00-1.50% Mo, 0.80-1.20% V, 0.05-0.15% Nb, 0.02-0.08% Ti, 0.05-0.15% Ce, P≤0.005%, S≤0.005%, and the balance is Fe.

2. The processing technology of the self-fluxing alloy repair powder according to claim 1, characterized in that: The self-fluxing alloy repair powder comprises the following processing steps: Step 1: Use discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing and cut the raw material into a size suitable for smelting; Step 2: Electroslag remelting: The raw materials are put into the electroslag remelting furnace, and the raw materials are heated by electric arc to melt into liquid metal, and unnecessary impurities are refined and removed; the liquid metal is cooled and solidified in the furnace to form an ingot; Step 3: Vacuum induction melting: The steel ingot is induction melted in a vacuum environment, and an induction current is used to heat the steel ingot to a molten state. After the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain alloy liquid; the alloy liquid is atomized into fine droplets, and the air flow quickly cools the droplets to form fine metal powder particles; the metal powder particles are collected to obtain uniform self-fluxing alloy repair powder.

3. The processing technology of the self-fluxing alloy repair powder according to claim 2, characterized in that: In step 1, the raw material is cut into blocks with a size of 50-100 mm.

4. The processing technology of the self-fluxing alloy repair powder according to claim 2, characterized in that: In step 2, the refining temperature is controlled at 1600-1650°C, and the refining time is 2-2.5h.

5. The processing technology of the self-fluxing alloy repair powder according to claim 2, characterized in that: In step 2, the slag system ratio in the electroslag remelting furnace is 55-58% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 12-15% magnesium oxide.

6. The processing technology of the self-fluxing alloy repair powder according to claim 2, characterized in that: In step 2, the molten metal is cooled in the furnace by gradient cooling, first by air cooling to 800°C, and then by water cooling to room temperature to form a steel ingot.

7. The processing technology of the self-fluxing alloy repair powder according to claim 2, characterized in that: In step 3, the alloy liquid is atomized into fine droplets using an argon-nitrogen mixed gas, with the ratio of argon to nitrogen being 4:1; during atomization, the oxygen content is ≤200ppm.

8. The processing technology of the self-fluxing alloy repair powder according to claim 3, characterized in that: In step 4, the self-fluxing alloy repair powder has a particle size of 60-90 μm, a D50 median particle size of 65-80 μm, a fluidity of >25s / 50g, and a sphericity of ≥95%.

9. The processing technology of the self-fluxing alloy repair powder according to claim 1, characterized in that: The self-fluxing alloy repair powder comprises 0.3% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.05% Ti, 0.1% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70 μm.

10. The processing technology of the self-fluxing alloy repair powder according to claim 1, characterized in that: The self-fluxing alloy repair powder comprises 0.25% C, 1.0% Si, 0.35% Mn, 5.0% Cr, 1.25% Mo, 1.0% V, 0.1% Nb, 0.05% Ti, 0.15% Ce, P≤0.005%, S≤0.005%, and the balance is Fe; the particle size of the self-fluxing alloy repair powder is 70 μm.

Images