Processing technology of a self-fusing alloy repair powder

Abstract

The present invention provides a processing technology for self-fluxing alloy repair powder. 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. The processing steps include an electroslag remelting and vacuum induction melting double refining process, which can deeply desulfurize, dephosphorize, and deboronize. Using waste H13 die steel as raw material, turning waste into treasure, and through 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, extremely long thermal fatigue life, low porosity, and low crack density are realized, significantly improving the performance of the repaired H13 die steel.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaics, and particularly relates to a processing technology for self-fusing alloy repair powder. Background Art

[0002] As an important material for photovoltaic aluminum profiles and structural components, the manufacturing process of photovoltaic aluminum profiles 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 die steel become key factors. In the manufacturing of photovoltaic aluminum profiles, as the core die material, H13 die steel is under the action of high temperature, high pressure, and corrosive media for a long time, and its performance is prone to deterioration due to thermal fatigue, oxidative wear, and surface cracks. According to statistics, the direct economic loss caused by die failure in the photovoltaic industry exceeds 1 billion yuan per year.

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

[0004] In view of this, the inventor of this case conducted in-depth research on the above problems, and thus this case was born. Summary of the Invention

[0005] The present invention aims to solve the deficiencies of H13 die steel repair metal powder in the prior art, and provides a processing technology for self-fusing alloy repair powder. Using waste H13 die steel as raw material, turning waste into treasure, and through the double refining processes of electroslag remelting and vacuum induction melting, deep desulfurization, dephosphorization, and deboronization can be achieved, and a self-fusing alloy repair powder with low P and S element contents, containing Nb, Ti, Ce elements, and without B element is prepared.

[0006] The present invention is implemented as follows: A processing technology for self - fluxing alloy repair powder. 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.

[0007] Further, the self - fluxing alloy repair powder comprises the following processing steps:

[0008] Step 1: Use waste H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting.

[0009] Step 2: Electroslag remelting: Put the raw material into an electroslag remelting furnace, heat the raw material through an electric arc to melt it into a metal liquid, and refine to remove unnecessary impurities; the metal liquid cools and solidifies in the furnace to form an ingot.

[0010] Step 3: Vacuum induction melting: Perform induction melting on the ingot in a vacuum environment, use induction current to heat the ingot to a molten state, after the temperature reaches 1650 °C, add appropriate amounts of Ti, Nb, and Ce in batches to obtain an alloy liquid; atomize the alloy liquid into fine droplets, and the gas flow quickly cools the droplets to form fine metal powder particles; collect the metal powder particles to obtain uniform self - fluxing alloy repair powder.

[0011] Further, in Step 1, the cutting size of the raw material is in the form of blocks with a size of 50 - 100 mm.

[0012] Further, in Step 2, the refining temperature is controlled at 1600 - 1650 °C, and the refining duration is 2 - 2.5 h.

[0013] Further, in Step 2, the slag system ratio in the electroslag remelting furnace is 55 - 58% calcium fluoride, 20% alumina, 10% calcium oxide, and 12 - 15% magnesium oxide.

[0014] Further, in Step 2, 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 an ingot.

[0015] Further, in Step 3, use a mixed gas of argon and nitrogen to atomize the alloy liquid into fine droplets, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤ 200 ppm.

[0016] Further, in step 4, the particle size of the self - fluxing alloy repair powder is 60 - 90 μm, the median particle size D50 is 65 - 80 μm, the fluidity is > 25 s / 50 g, and the sphericity is ≥ 95%.

[0017] Further, 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.

[0018] Further, 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.

[0019] The advantages of the present invention are as follows:

[0020] 1. The particle size of the self - fluxing alloy repair powder is 60 - 90 μm, the median particle size D50 is 65 - 80 μm, the fluidity is > 25 s / 50 g, and the sphericity is ≥ 95%; the particle size of 60 - 90 μm can affect the quality of the subsequent repair cladding layer. If the particle size is too large, it will affect the melting of the powder, and if it is too small, it is easy to oxidize or scatter; the fluidity > 25 s / 50 g makes the powder have good fluidity, which helps to evenly feed the powder; the sphericity ≥ 95% helps the fluidity and melting effect of the powder.

[0021] 2. The processing technology of the self - fluxing alloy repair powder of the present invention uses waste H13 die steel as raw material, turning waste into treasure, and through the coordinated cooperation of the double refining processes of electroslag remelting (ESR) + vacuum induction melting (VIM), deep desulfurization, dephosphorization and deboronization can be achieved; 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, long thermal fatigue life, low porosity and low crack density are realized, significantly improving the performance of the repaired H13 die steel. Description of the Drawings

[0022] The present invention will be further described below with reference to the drawings in conjunction with embodiments.

[0023] Figure 1 It is a schematic structural diagram of the self - fluxing alloy repair powder prepared in Example 1 of the present invention. Detailed Embodiments

[0024] 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 of the specification and specific embodiments.

[0025] Please refer to Figure 1 As shown, the present invention provides a processing technology for self-fluxing alloy repair powder. 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 - 90μm, the D50 median particle size is 65 - 80μm, the fluidity > 25s / 50g, and the sphericity ≥ 95%. The particle size of 60 - 90μm can affect the quality of the subsequent repaired cladding layer. If the particle size is too large, it will affect the melting of the powder; if it is too small, it is easy to oxidize or scatter. The fluidity > 25s / 50g makes the powder have good fluidity, which helps to evenly feed the powder. The sphericity ≥ 95% helps the fluidity and melting effect of the powder.

[0026] The self-fluxing alloy repair powder includes the following processing steps:

[0027] Step 1: Use the discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting.

[0028] Step 2: Electroslag remelting (ESR): Put the raw material into the electroslag remelting furnace, heat the raw material through an electric arc to melt it into a metal liquid, refine and remove unnecessary impurities such as S, P, and B; the metal liquid cools and solidifies in the furnace to form an ingot.

[0029] Step 3: Vacuum induction melting (VIM): Induction melt the ingot in a vacuum environment, use the induction current to heat the ingot to the melting state. After the temperature reaches 1650°C, add appropriate amounts of Ti, Nb, and Ce in batches to obtain an alloy liquid; atomize the alloy liquid into fine droplets, and the gas flow quickly cools the droplets to form fine metal powder particles; collect the metal powder particles to obtain uniform self-fluxing alloy repair powder. Adding Ti first can prevent oxidation, then adding Nb, and finally adding Ce to avoid the preferential reaction of Ce with oxygen.

[0030] The processing technology of the self-fluxing alloy repair powder of the present invention uses waste H13 die steel as raw material, turning waste into treasure, and through the coordinated cooperation of the double refining processes of electroslag remelting (ESR) + vacuum induction melting (VIM), it can deeply desulfurize, dephosphorize and deboronize; 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, extremely long thermal fatigue life, low porosity and low crack density are realized, significantly improving the performance of the repaired H13 die steel.

[0031] In step 1 of the present invention, the cutting size of the raw material is in the form of blocks of 50 - 100 mm. Being too small (<50 mm) may lead to intensified oxidation, and being too large (>100 mm) will affect the melting efficiency and uniformity of electroslag remelting.

[0032] In step 2 of the present invention, the refining temperature is controlled at 1600 - 1650 °C, and the refining duration is 2 - 2.5 h. This temperature range can effectively remove P and S impurities. 1600 - 1650 °C is close to the volatilization temperature of boron oxide. Extending the refining time to 2 - 2.5 hours promotes the oxidation of boron and its adsorption by the slag phase, and the boron content can be controlled at ≤0.001%, meeting the requirement of no boron (B).

[0033] In step 2 of the present invention, the slag system ratio in the electroslag remelting furnace is 55 - 58% calcium fluoride, 20% alumina, 10% calcium oxide, and 12 - 15% magnesium oxide. Calcium fluoride dominates desulfurization, and the desulfurization efficiency can be improved by forming calcium sulfide and entering the slag phase; alumina enhances the stability of the slag system; calcium oxide is used to assist in dephosphorization, and magnesium oxide forms stable magnesium borate with boron oxide in the raw material to achieve deep deboronization. The higher the proportion of magnesium oxide, the better the deboronization effect.

[0034] In step 2 of the present invention, the molten metal is cooled in the furnace by gradient cooling. First, it is air-cooled to 800 °C, and then water-cooled to room temperature to form an ingot. Gradient cooling of the ingot can avoid internal stress cracks.

[0035] In step 3 of the present invention, the alloy liquid is atomized into fine droplets using a mixed gas of argon and nitrogen, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content is ≤200 ppm to ensure the atomization quality.

[0036] The present invention also provides a repair process for H13 die steel, including the following steps:

[0037] Step 1: Clean and decontaminate the surface of the H13 die steel to be repaired, anneal it at 650°C for 2 hours, and preheat. The preheating temperature is 400 - 500°C, and an infrared thermometer is used for real-time monitoring. Preheating can avoid thermal cracks caused by excessive temperature difference. The melting point of H13 die steel is about 850°C, and preheating below 300°C is not sufficient to eliminate thermal stress. Annealing at 650°C eliminates residual stress, and preheating at 400 - 500°C avoids thermal stress, which is in line with the heat treatment characteristics of H13 die steel.

[0038] Step 2: Use a fiber laser cladding system for cladding. Adjust the parameters of the fiber laser cladding system. The laser power is 800 - 1200W, the spot diameter is 1.5 - 2.0mm, the laser scanning speed is 6 - 8mm / s, the powder feeding rate is 5 - 8g / min, the layer thickness is 0.2 - 1.0mm, the overlap rate is 30 - 50%, and the 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 alloy liquid in a local area to the melting state. Setting the laser power at 800 - 1200W is suitable for fine repair; setting the spot diameter at 1.5 - 2.0mm is suitable for high-precision repair; the powder feeding rate is 5 - 8g / min. If the powder feeding rate is too low, it will affect the cladding efficiency, and if it is too high, it is easy to cause powder accumulation or inclusion; the laser scanning speed of 6 - 8mm / s is suitable for fine cladding; the overlap rate of 30 - 50% ensures a uniform cladding layer without obvious gaps; the focus position of 0 - 1mm is used to control the cladding depth.

[0039] Step 3: The alloy liquid is sent to the surface of the H13 die steel to be repaired, and the laser beam interacts with the alloy liquid to form a solid cladding layer. The cladding is carried out by the method of layer-by-layer stacking. The thickness of each cladding layer is controlled within 0.2 - 1.0mm to ensure good cladding bonding and surface flatness. During this process, a protective gas is introduced to help the self-fluxing alloy repair powder flow and also avoid oxidation.

[0040] Step 4: After stress relief annealing the cladding layer at 550°C for 2 hours, perform cryogenic treatment, and then use a high-precision CNC grinding machine for trimming and polishing; the repair is completed.

[0041] For the H13 die steel of photovoltaic aluminum profiles obtained by this repair method, the hardness of the cladding layer is controlled at 720 ± 20HV, the porosity is <1%, there are basically no cracks, and the service life is extended by 150 - 200%.

[0042] The following shows the beneficial technical effects of a processing technology of a self-fluxing alloy repair powder of the present invention through several experimental groups and control groups.

[0043] Experimental Group 1

[0044] A self-fluxing alloy repair powder includes the following processing steps:

[0045] Step 1: Use the discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100 mm blocks.

[0046] Step 2: Electroslag remelting (ESR): Put the raw material into the electroslag remelting furnace, heat the raw material by an electric arc to melt it into a metal liquid, refine to remove unnecessary impurities; 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 an ingot; the refining temperature is controlled at 1600 - 1650 °C, and the refining duration is 2.5 h. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% aluminum oxide, 10% calcium oxide, and 15% magnesium oxide.

[0047] Step 3: Vacuum induction melting (VIM): Perform induction melting on the ingot in a vacuum environment, use the induction current to heat the ingot to the melting state, after the temperature reaches 1650 °C, add appropriate amounts of Ti, Nb, and Ce in batches to obtain an alloy liquid; atomize the alloy liquid into fine droplets, and the air flow quickly cools the droplets to form fine metal powder particles; collect the metal powder particles to obtain uniform self-fusing alloy repair powder. Use a mixed gas of argon and nitrogen to atomize the alloy liquid into fine droplets, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤ 200 ppm.

[0048] Perform quality inspection on the self-fusing alloy repair powder to check its composition, particle size distribution, fluidity and other indicators. The self-fusing 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-fusing alloy repair powder is 70 μm, the D50 median particle size is 70 μm, the fluidity > 25 s / 50 g, and the sphericity ≥ 95%.

[0049] Experimental group 2

[0050] A kind of self-fusing alloy repair powder includes the following processing steps:

[0051] Step 1: Use the discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100 mm blocks.

[0052] Step 2: Electroslag Remelting (ESR): The raw materials are put into an electroslag remelting furnace, and the raw materials are heated by an electric arc to melt them into molten metal, and unnecessary impurities are removed by refining; the molten metal is cooled in the furnace by gradient cooling, 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 duration is 2.5 h. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% alumina, 10% calcium oxide, and 15% magnesium oxide.

[0053] Step 3: Vacuum Induction Melting (VIM): The ingot is subjected to induction melting in a vacuum environment, and the ingot is heated to a molten state using induction current. After the temperature reaches 1650 °C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain an alloy liquid; the alloy liquid is atomized into fine droplets, and the droplets are rapidly cooled by an air stream to form fine metal powder particles; the metal powder particles are collected to obtain a uniform self-fluxing alloy repair powder. The alloy liquid is atomized into fine droplets using a mixed gas of argon and nitrogen, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤ 200 ppm.

[0054] Quality inspection is carried out on the self-fluxing alloy repair powder 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 70 μm, the D50 median particle size is 70 μm, the fluidity > 25 s / 50 g, and the sphericity ≥ 95%.

[0055] Experimental Group 3

[0056] A self-fluxing alloy repair powder includes the following processing steps:

[0057] Step 1: Use waste H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100 mm in block.

[0058] Step 2: Electroslag Remelting (ESR): The raw materials are put into an electroslag remelting furnace, and the raw materials are heated by an electric arc to melt them into molten metal, and unnecessary impurities are removed by refining; the molten metal is cooled in the furnace by gradient cooling, 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 duration is 2.5 h. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% alumina, 10% calcium oxide, and 15% magnesium oxide.

[0059] Step 3: Vacuum Induction Melting (VIM): The ingot is subjected to induction melting in a vacuum environment. The ingot is heated to a molten state using induction current. After the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain an 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 a mixed gas of argon and nitrogen, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤ 200 ppm.

[0060] Quality inspection is carried out on the self-fluxing alloy repair powder 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 > 25 s / 50 g, and the sphericity ≥ 95%.

[0061] Experimental Group 4

[0062] A self-fluxing alloy repair powder includes the following processing steps:

[0063] Step 1: Use waste H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100 mm in block shape.

[0064] Step 2: Electroslag Remelting (ESR): The raw material is put into an electroslag remelting furnace, and the raw material is melted into a metal liquid by arc heating, and unnecessary impurities are removed by refining; the metal liquid is cooled in the furnace using gradient cooling. First, it is 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 duration is 2.5 h. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% alumina, 10% calcium oxide, and 15% magnesium oxide.

[0065] Step 3: Vacuum Induction Melting (VIM): The ingot is subjected to induction melting in a vacuum environment. The ingot is heated to a molten state using induction current. After the temperature reaches 1650°C, appropriate amounts of Ti, Nb, and Ce are added in batches to obtain an 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 a mixed gas of argon and nitrogen, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤ 200 ppm.

[0066] Perform quality inspection on the self-fluxing alloy repair powder 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 > 25s / 50g, and the sphericity ≥ 95%.

[0067] Control Group 1

[0068] A self-fluxing alloy repair powder includes the following processing steps:

[0069] Step 1: Use the discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100mm blocks.

[0070] Step 2: Electro-slag remelting (ESR): Put the raw material into the electro-slag remelting furnace, heat the raw material by arc to melt it into a metal liquid, and refine to remove unnecessary impurities; the metal liquid is cooled by gradient 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 duration is 2.5h. The slag system ratio in the electro-slag remelting furnace is 55% calcium fluoride, 20% alumina, 10% calcium oxide, and 15% magnesium oxide.

[0071] Step 3: Vacuum induction melting (VIM): Perform induction melting on the ingot in a vacuum environment, use the induction current to heat the ingot to the melting state, and after the temperature reaches 1650°C, add an appropriate amount of Ce to obtain an alloy liquid; atomize the alloy liquid into fine droplets, and the gas flow quickly cools the droplets to form fine metal powder particles; collect the metal powder particles to obtain a uniform self-fluxing alloy repair powder. Use a mixed argon-nitrogen gas to atomize the alloy liquid into fine droplets, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤ 200ppm.

[0072] Perform quality inspection on the self-fluxing alloy repair powder 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 > 25s / 50g, and the sphericity ≥ 95%.

[0073] Control Group 2

[0074] A self - fluxing alloy repair powder includes the following processing steps:

[0075] Step 1: Use waste H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse with clean water; conduct crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100 - mm blocks.

[0076] Step 2: Electroslag remelting (ESR): Put the raw material into an electroslag remelting furnace, heat the raw material through an electric arc to melt it into a metal liquid, refine to remove unnecessary impurities; the metal liquid is cooled in the furnace using gradient cooling, 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 duration is 2.5 h. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% alumina, 10% calcium oxide, and 15% magnesia.

[0077] Step 3: Vacuum induction melting (VIM): Conduct induction melting on the ingot in a vacuum environment, use induction current to heat the ingot to a molten state, after the temperature reaches 1650 °C, add appropriate amounts of Ti and Nb in batches to obtain an alloy liquid; atomize the alloy liquid into fine droplets, and the gas flow quickly cools the droplets to form fine metal powder particles; collect the metal powder particles to obtain a uniform self - fluxing alloy repair powder. Use a mixed argon - nitrogen gas to atomize the alloy liquid into fine droplets, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤ 200 ppm.

[0078] Conduct quality inspection on the self - fluxing alloy repair powder 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 70 μm, the D50 median particle size is 70 μm, the fluidity > 25 s / 50 g, and the sphericity ≥ 95%.

[0079] Comparison group 3

[0080] A self - fluxing alloy repair powder includes the following processing steps:

[0081] Step 1: Use waste H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse with clean water; conduct crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100 - mm blocks.

[0082] Step 2: Electroslag Remelting (ESR): The raw materials are put into an electroslag remelting furnace, and the raw materials are melted into molten metal by arc heating to refine and remove unnecessary impurities; the molten metal is cooled in the furnace by gradient cooling, 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 duration is 2.5 h. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% alumina, 10% calcium oxide, and 15% magnesium oxide.

[0083] Step 3: Vacuum Induction Melting (VIM): The ingot is subjected to induction melting in a vacuum environment, and the ingot is heated to a molten state using induction current. After the temperature reaches 1650 °C, appropriate amounts of Ti, excessive Nb, and appropriate amounts of Ce are added in batches to obtain an alloy liquid; the alloy liquid is atomized into fine droplets, and the droplets are rapidly cooled by an air flow 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 a mixed gas of argon and nitrogen, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤ 200 ppm.

[0084] Quality inspection is carried out on the self-fluxing alloy repair powder 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 70 μm, the D50 median particle size is 70 μm, the fluidity > 25 s / 50 g, and the sphericity ≥ 95%.

[0085] Control Group 4

[0086] A self-fluxing alloy repair powder includes the following processing steps:

[0087] Step 1: Use waste H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100 mm in block.

[0088] Step 2: Electroslag Remelting (ESR): The raw materials are put into an electroslag remelting furnace, and the raw materials are melted into molten metal by arc heating to refine and remove unnecessary impurities; the molten metal is cooled in the furnace by gradient cooling, 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 duration is 2.5 h. The slag system ratio in the electroslag remelting furnace is 55% calcium fluoride, 20% alumina, 10% calcium oxide, and 15% magnesium oxide.

[0089] Step 3: Vacuum Induction Melting (VIM): The steel ingot is subjected to induction melting in a vacuum environment. The steel ingot is heated to the molten state using induced current. After the temperature reaches 1650 °C, an excessive amount of Ti, an appropriate amount of Nb, and an appropriate amount of Ce are added in batches to obtain an alloy liquid. The alloy liquid is atomized into fine droplets, and the airflow rapidly 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 a mixed gas of argon and nitrogen, and the ratio of argon to nitrogen is 4:1. During atomization, the oxygen content ≤ 200 ppm.

[0090] Quality inspection is carried out on the self-fluxing alloy repair powder 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 70 μm, the D50 median particle size is 70 μm, the fluidity > 25 s / 50 g, and the sphericity ≥ 95%.

[0091] Control Group 5

[0092] A self-fluxing alloy repair powder includes the following processing steps:

[0093] Step 1: Use waste H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100 mm in block shape.

[0094] Step 2: The raw material is put into the furnace and melted into a metal liquid; 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 a steel ingot.

[0095] Step 3: Vacuum Induction Melting (VIM): The steel ingot is subjected to induction melting in a vacuum environment. The steel ingot is heated to the molten state using induced current. After the temperature reaches 1650 °C, an appropriate amount of Ti, Nb, and Ce are added in batches to obtain an alloy liquid. The alloy liquid is atomized into fine droplets, and the airflow rapidly 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 a mixed gas of argon and nitrogen, and the ratio of argon to nitrogen is 4:1. During atomization, the oxygen content ≤ 200 ppm.

[0096] Perform quality inspection on the self-fluxing alloy repair powder 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 70μm, the D50 median particle size is 70μm, the fluidity > 25s / 50g, and the sphericity ≥ 95%.

[0097] Control Group 6

[0098] A self-fluxing alloy repair powder includes the following processing steps:

[0099] Step 1: Use the waste H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 100mm blocks.

[0100] Step 2: Electroslag remelting (ESR): Put the raw material into the electroslag remelting furnace, heat the raw material by arc to melt it into a metal liquid, and refine to remove unnecessary impurities; 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 an ingot; the refining temperature is controlled at 1600 - 1650°C, and the refining duration is 2.5h. The slag system ratio in the electroslag remelting furnace is 70% calcium fluoride, 20% alumina, and 10% calcium oxide.

[0101] Step 3: Vacuum induction melting (VIM): Perform induction melting on the ingot in a vacuum environment, use the induction current to heat the ingot to the melting state, after the temperature reaches 1650°C, add appropriate amounts of Ti, Nb, and Ce in batches to obtain an alloy liquid; atomize the alloy liquid into fine droplets, and the air flow quickly cools the droplets to form fine metal powder particles; collect the metal powder particles to obtain a uniform self-fluxing alloy repair powder. Use a mixed argon-nitrogen gas to atomize the alloy liquid into fine droplets, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤ 200ppm.

[0102] Perform quality inspection on the self-fluxing alloy repair powder 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 > 25s / 50g, and the sphericity ≥ 95%.

[0103] The self - fluxing alloy repair powders prepared from experimental groups 1 - 4 and control groups 1 - 6 were applied to the repair process of the H13 die steel of the present invention, and various performance indexes of the repaired H13 die steel were tested.

[0104]

[0105] Conclusion:

[0106] 1. For the self - fluxing alloy repair powders prepared from experimental groups 1 - 4, by controlling the contents of Nb (0.05 - 0.15%), Ti (0.02 - 0.08%), and Ce (0.05 - 0.15%), strictly limiting P and S ≤ 0.005%, and not containing B, the advantages of high hardness, high bonding strength, ultra - long thermal fatigue life, low porosity, and low crack density of the cladding layer of H13 die steel are achieved, significantly improving the performance of the repaired H13 die steel.

[0107] 2. The slag system ratio of the electroslag remelting (ESR) process in experimental groups 1 - 4, combined with a refining temperature of 1650 °C and a refining time of 2.5 h, realizes deep desulfurization (S ≤ 0.005%), dephosphorization (P ≤ 0.005%), and deboronation (B ≤ 0.001%). The B residue (0.1%) in control group 5 (without electroslag remelting ESR) and control group 6 (slag system without magnesium oxide) results in a thermal fatigue life that is only 1 / 3 of that of the experimental group.

[0108] 3. The vacuum induction melting (VIM) process of experimental groups 1 - 4, combined with adding Ti, Nb, and Ce in batches, ensures the uniform distribution of micro - alloying elements; the hardness, bonding strength, and crack density of control group 1 (without adding Nb and Ti) and control group 2 (without adding Ce) are significantly reduced; brittle phases are generated in control group 3 (Nb excessive to 0.25%) and control group 4 (Ti excessive to 0.15%), and the performance drops significantly.

[0109] 4. The content of P and S ≤ 0.005% in experimental groups 1 - 4 significantly reduces brittleness, and the complete removal of B (≤ 0.001%) avoids thermal fatigue cracks. The crack density (8.7 cracks / mm²) and porosity (2.1%) of control group 5 (with P, S, and B residues) far exceed those of the experimental group.

[0110] Although the specific implementation manners of the present invention are described above, those skilled in the art should understand that the specific embodiments we described are illustrative rather than used to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered by the scope protected by the claims of the present invention.

Claims

1. A processing technology for self-fluxing alloy repair powder, characterized in that: The self-fusing 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 self-fusing alloy repair powder includes the following processing steps: Step 1: Use the discarded H13 die steel as raw material, scrub it with dilute hydrochloric acid and then rinse it with clean water; perform crushing treatment to cut the raw material into a size suitable for smelting; the cutting size of the raw material is 50-100mm in block shape; Step 2: Electroslag remelting: Put the raw material into the electroslag remelting furnace, heat the raw material by electric arc to melt it into metal liquid, and refine to remove unnecessary impurities; the metal liquid cools and solidifies in the furnace to form an ingot; the refining temperature is controlled at 1600-1650°C, and the refining duration is 2-2.5h; the slag system ratio in the electroslag remelting furnace is 55-58% calcium fluoride, 20% alumina, 10% calcium oxide, 12-15% magnesium oxide; Step 3: Vacuum induction melting: Induction melt the ingot in a vacuum environment, use induction current to heat the ingot to the melting state, after the temperature reaches 1650°C, add appropriate amounts of Ti, Nb, and Ce in batches to obtain alloy liquid; atomize the alloy liquid into fine droplets, and the air flow quickly cools the droplets to form fine metal powder particles; collect the metal powder particles to obtain uniform self-fusing alloy repair powder.

2. The processing technology of the self-fusing alloy repair powder according to claim 1, characterized in that: In Step 2, 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.

3. The processing technology of the self-fusing alloy repair powder according to claim 1, characterized in that: In Step 3, use a mixed gas of argon and nitrogen to atomize the alloy liquid into fine droplets, and the ratio of argon to nitrogen is 4:1; during atomization, the oxygen content ≤200ppm.

4. The processing technology of the self-fusing alloy repair powder according to claim 1, characterized in that: In Step 4, the particle size of the self-fusing alloy repair powder is 60-90μm, the D50 median particle size is 65-80μm, the fluidity >25s / 50g, and the sphericity ≥95%.

5. The processing technology of the self-fusing alloy repair powder according to claim 1, characterized in that: The self-fusing 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-fusing alloy repair powder is 70μm.

6. The processing technology of the self-fusing alloy repair powder according to claim 1, characterized in that: The self-fusing 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-fusing alloy repair powder is 70μm.

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