Oxidation-resistant high-strength stainless steel for ovens and method for manufacturing the same

Abstract

The application relates to the technical field of stainless steel surface treatment, and discloses a high-oxidation-resistance high-strength stainless steel for ovens and a preparation method thereof; the preparation method comprises the following operation steps: step 1: after iron is melted at 1550-1600 DEG C, chromium, nickel, manganese, aluminum, cobalt and titanium are added, the temperature is raised to 1650-1700 DEG C, and smelting is carried out for 1.5-2 hours, the dross is cleaned, and a steel liquid is obtained; the steel liquid is cast into a shape, and is sequentially subjected to forging, hot rolling, heat treatment, and the like, so that an oven stainless steel base plate is obtained; step 2: the oven stainless steel base plate is immersed in an electrophoresis tank liquid for 2-3 minutes, is taken out, is washed, and is dried; laser cladding and sintering treatment are further carried out, and a high-oxidation-resistance high-strength stainless steel is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel surface treatment, in particular to an oxidation-resistant high-strength stainless steel for ovens and a preparation method thereof. Background Art

[0002] Traditional stainless steel is prone to oxidation and strength loss after long-term use in high-temperature oven environments. While performance can be improved by adding elements like chromium and nickel or by using surface coatings, these can lead to drawbacks such as poor bonding and reduced workability. Existing technologies, such as physical vapor deposition (PVD), require expensive equipment, while conventional electroplating or spray coatings are prone to flaking at high temperatures, making them difficult to meet the requirements for long-term oxidation resistance and high strength. Furthermore, nanomaterials can improve oxidation resistance, but dispersibility and interfacial bonding remain challenges.

[0003] On the other hand, in the existing technology, ceramic materials are usually laser-clad on the surface of stainless steel to improve oxidation resistance. However, there is a problem of large difference in thermal expansion coefficient between the stainless steel substrate and the ceramic material, which will affect the cladding layer and result in low oxidation resistance of the stainless steel.

[0004] In summary, in order to solve the above problems, it is of great significance to prepare an oxidation-resistant and high-strength stainless steel for ovens. Summary of the Invention

[0005] The object of the present invention is to provide an oxidation-resistant high-strength stainless steel for oven use and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing oxidation-resistant high-strength oven-use stainless steel comprises the following steps:

[0008] Step 1: After melting iron at 1550-1600°C, add chromium, nickel, manganese, aluminum, cobalt, and titanium, heat it to 1650-1700°C and smelt it for 1.5-2 hours, remove the slag, and obtain molten steel; cast it into shape, and then perform forging, hot rolling, and heat treatment in sequence to obtain a stainless steel substrate for oven use;

[0009] Step 2: Immerse the stainless steel substrate for the oven in the electrophoretic tank liquid for electrophoretic deposition for 2 to 3 minutes, take it out, wash it, and dry it; then perform laser cladding and sintering to obtain oxidation-resistant high-strength stainless steel.

[0010] More optimally, the raw materials of the stainless steel substrate for the oven include the following components: 16-20wt% chromium, 8-12wt% nickel, 1-2wt% manganese, 0.1-0.3wt% aluminum, 0.5-1.5wt% cobalt, 0.32-0.45wt% titanium, and the rest is iron.

[0011] More optimally, the raw materials of the electrophoresis tank liquid include the following components: 10-20 parts of modified nano zinc oxide, 90-100 parts of ethanol aqueous solution, and 0.1-0.13 parts of KNO3, by mass; the concentration of the ethanol aqueous solution is 70-80wt%.

[0012] A more optimized preparation method of the modified nano zinc oxide is as follows: N-aminoethyl-3-aminopropyltriethoxysilane is added to an ethanol aqueous solution for 30 to 40 minutes to obtain a mixed solution; branched polysiloxane is added to a tetrahydrofuran aqueous solution containing NaOH, refluxed for 4 to 5 hours, cooled to room temperature, adjusted to a neutral pH, added to the mixed solution and mixed uniformly, adjusted to a pH of 6 to 6.5, added to a nano zinc oxide-ethanol aqueous solution, stirred for 4 to 6 hours, filtered, washed, added to anhydrous ethanol, and Soxhlet extracted for 10 to 15 hours to obtain modified nano zinc oxide.

[0013] More optimally, the mass ratio of the N-aminoethyl-3-aminopropyltriethoxysilane, branched polysiloxane, and nano-zinc oxide is (0.2-0.4):(0.5-0.7):(2-3); the N-aminoethyl-3-aminopropyltriethoxysilane accounts for 2-4wt% of the ethanol aqueous solution; the branched polysiloxane accounts for 5-8wt% of the tetrahydrofuran aqueous solution; the nano-zinc oxide accounts for 7-10wt% of the ethanol aqueous solution; the concentration of the ethanol aqueous solution is 70-80wt%; in the tetrahydrofuran aqueous solution, the NaOH concentration is 0.01-0.03M, and the mass ratio of tetrahydrofuran to deionized water is (7-8):2.

[0014] The more optimized preparation method of the branched polysiloxane is as follows: (1) vinyl-terminated polydimethylsiloxane is added to toluene and mixed evenly, Karstedt catalyst is added and mixed evenly, and the mixture is heated to 50-55°C under nitrogen protection, trimethoxysilane-toluene solution is added and stirred for 8-10 hours, the mixture is heated to 60-65°C, activated carbon is added and stirred for 0.5-1 hour, the mixture is immediately cooled to room temperature, filtered, and the liquid is rotary evaporated to remove the solvent to obtain a silane monomer; (2) the silane monomer and acetic anhydride are uniformly mixed, tetrakis(trimethylsiloxy)titanium is added, the mixture is heated to 55-60°C under nitrogen atmosphere, vacuumized for 3-4 hours, acetoxypropyltrimethoxysilane is added and mixed evenly, and vacuumized for 3-4 hours to obtain a branched polysiloxane.

[0015] More optimally, the raw materials of the silane monomer include the following components: 0.18~0.3 parts of vinyl-terminated polydimethylsiloxane, 0.25~0.35 parts of trimethoxysilane, 0.08~0.12 parts of Karstedt catalyst, and 50~60 parts of toluene, by mass; the molar ratio of the acetic anhydride, silane monomer, and acetoxypropyltrimethoxysilane is 1.5:1:(0.2~0.3).

[0016] The more optimized process conditions of the electrophoretic deposition are: the pH of the electrophoretic tank liquid is 6~7, the temperature is 25~35℃, and the pulse voltage is 80~100V; the process conditions of the laser cladding are: the cladding material includes nickel powder, nano-silicon dioxide, and nano-yttrium oxide in a mass ratio of 7:3:(1~2), the overlap rate of the laser scanning is 50~60%, the laser power is 2.2~2.4kW, and the scanning speed is 6~8mm / s; the process conditions of the sintering treatment are: temperature is 700~800℃, and time is 2~3 hours.

[0017] More optimized, the forging process conditions are: initial forging temperature of 1100~1200℃, cumulative deformation of 60~70%, deformation of 30%~40% per pass, final forging temperature of 900~1000℃, air cooling; the hot rolling process conditions are: starting rolling temperature of 1050~1150℃, final rolling temperature of 800~900℃, total reduction rate of 70~80%, air cooling; the heat treatment process conditions are: keeping at 1010~1150℃ for 1~2 hours, water quenching; keeping at 850~950℃ for 8~10 hours, air cooling.

[0018] Compared with the prior art, the present invention has the following beneficial effects: the present invention optimizes the composition of the stainless steel matrix and combines electrophoretic deposition of modified nano zinc oxide and laser cladding of nano ceramic layers to form a dense and stable protective structure;

[0019] In this solution, the forging and hot rolling processes can make the steel grains finer, thereby enhancing its strength and toughness; and heat treatment is then used to adjust the steel's structure, making it more tough, able to maintain a certain strength at high temperatures, and less prone to deformation.

[0020] In order to further improve the oxidation resistance of stainless steel used in ovens, nano-silicon dioxide is laser-clad on its surface. However, nano-silicon dioxide has a high melting point and is not easy to form a molten pool on the stainless steel surface. Therefore, nickel powder is added, which has good compatibility with stainless steel and can form a molten pool on the stainless steel surface. Nano-yttrium oxide is added to inhibit the coarsening of the cladding layer grains, thereby improving the density and oxidation resistance of the coating. The flow of liquid metal on the stainless steel surface can drive the nanoparticles to migrate to the gaps. Under the negative pressure generated by solidification shrinkage, the nanoparticles are easily filled into loose or porous areas, reducing stress concentration points, thereby improving its mechanical properties and oxidation resistance.

[0021] In order to improve the adhesion of ceramic materials on the stainless steel substrate, a layer of polysiloxane-modified nano-zinc oxide is electrophoretically deposited on the surface of the stainless steel substrate, forming a continuous and dense coating with a certain flexibility after drying; the electrophoretic layer can serve as a transition layer, evenly covering the stainless steel substrate, improving the surface roughness and chemical activity, and providing better wettability and adhesion for subsequent laser cladding.

[0022] In the scheme, acetic anhydride reacts with the methoxy group (-OCH3) of the silane monomer to generate acetoxysilane (-OCOCH3), thereby improving the reaction activity. Tetrakis(trimethylsilyl)titanium acts as a Lewis acid catalyst to promote the condensation of siloxane (Si-O-Si) to form a branched structure. Acetoxypropyltrimethoxysilane provides additional cross-linking sites to enhance the degree of branching. The branched polysiloxane is refluxed in a NaOH / ethanol solution to hydrolyze the acetoxy and methoxy groups into silanols (Si-OH), thereby improving the hydrophilicity. The condensation of silanols (Si-OH) with the hydroxyl groups (Zn-OH) on the surface of nano-zinc oxide is enhanced to form Zn-O-Si covalent bonds. N-aminoethyl-3-aminopropyltriethoxysilane (AEAPTES) provides -NH2 groups, and KNO3 provides conductive ions. The charge regulation effect of AEAPTES makes the Zeta potential of ZnO particles more stable, prevents sedimentation, avoids uneven coating due to agglomeration during electrophoresis, and optimizes electrophoresis efficiency.

[0023] In the scheme, branched polysiloxane will decompose into SiO2 and CO2 under high laser temperature (>1000℃); in order to reduce the carbon content of polysiloxane during the cladding process, the side chains in branched polysiloxane are mainly methyl, rather than phenyl or long-chain alkyl polysiloxanes. Because the aromatic ring structure of phenyl is stable, it may not be completely decomposed at high temperature to produce carbon slag, which hinders the oxidation of silicon; through branching modification, the proportion of Si and O in the molecule is increased, the relative content of carbon element is reduced, the thermal stability of the molecule is improved, and the residual organic components caused by premature decomposition at low temperature are avoided.

[0024] During the laser cladding process, branched polysiloxane and N-aminoethyl-3-aminopropyltriethoxysilane decompose into a high-temperature resistant Si-O network that is compatible with the SiO2 in the cladding layer, reducing peeling caused by thermal stress and thus improving oxidation resistance. At the same time, its organic chain segments can buffer the thermal expansion difference between the stainless steel substrate and the laser cladding layer, thereby inhibiting the generation of cracks during the laser cladding process.

[0025] As an inorganic phase, nano zinc oxide can diffuse or slightly react with the stainless steel matrix (iron, chromium and other elements) and the nickel powder in the cladding layer to improve the overall bonding strength; the high-temperature stability of nano zinc oxide can stabilize the flow of the molten pool and reduce spatter; and through high-temperature sintering treatment, the internal stress of the laser cladding layer can be eliminated, the ceramic transformation of the electrophoretic layer can be further improved, and the generation of pores in the organic chain segments during the cladding process can be reduced, thereby further enhancing the oxidation resistance. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] In the scheme, the preparation method of branched polysiloxane is as follows: (1) adding 0.18 parts of vinyl-terminated polydimethylsiloxane to 10 parts of toluene and mixing uniformly, adding 0.08 parts of Karstedt catalyst and mixing uniformly, heating to 50°C under nitrogen protection, adding trimethoxysilane-toluene solution (0.3 parts of trimethoxysilane, 10 parts of toluene), stirring for 8 hours, heating to 60°C, adding activated carbon and continuing stirring for 0.5 hours, immediately cooling to room temperature, filtering, and rotary evaporating the liquid to remove the solvent to obtain silane monomer; (2) weighing acetic anhydride, silane monomer, and acetoxypropyltrimethoxysilane in a molar ratio of 1.5:1:0.2; uniformly mixing the silane monomer and acetic anhydride, adding 0.15 parts of tetrakis(trimethylsiloxy)titanium, heating to 60°C under nitrogen atmosphere, vacuuming for 3 hours, adding acetoxypropyltrimethoxysilane and mixing uniformly, and continuing vacuuming for 3 hours to obtain branched polysiloxane.

[0028] In the following specific embodiments, parts are by mass. In this embodiment, it should be noted that the purchase manufacturers of all raw materials involved in the present invention are not subject to any special restrictions. Examples include: vinyl-terminated polydimethylsiloxane with a CAS number of 68083-18-1; Karstedt catalyst with a CAS number of 81032-58-8; trimethoxysilane with a CAS number of 2487-90-3; acetic anhydride with a CAS number of 108-24-7; acetoxypropyltrimethoxysilane with a CAS number of 108-24-7; The CAS number of methoxysilane is 59004-18-1; the CAS number of tetrakis(trimethylsilyl)titanium is 15990-66-6; the CAS number of N-aminoethyl-3-aminopropyltriethoxysilane is 5089-72-5; the product number of nano-zinc oxide is YM-ZnO, with an average particle size of 50nm; the product number of nano-silicon dioxide is XH-SiO2, with an average particle size of 50nm; the product number of nano-yttrium oxide is XH-Y2O3, with an average particle size of 50nm.

[0029] Example 1, a method for preparing oxidation-resistant high-strength oven stainless steel, comprising the following steps:

[0030] Step 1: After melting iron at 1550°C, chromium, nickel, boron, manganese, aluminum, cobalt, and titanium are added, and the temperature is raised to 1650°C and smelted for 2 hours. The slag is removed to obtain molten steel, which is cast into shape. The steel is then forged (initial forging at 1150°C, cumulative deformation of 60%, deformation of each pass of 30%, final forging temperature of 900°C, and air cooling), hot rolled (start rolling temperature of 1050°C, final rolling temperature of 850°C, total reduction rate of 70%, and air cooling), and heat treated (holding at 1010°C for 2 hours, water quenching; holding at 900°C for 8 hours, and air cooling) to obtain an oven-safe stainless steel substrate.

[0031] The raw materials of the stainless steel substrate for ovens include the following components: 18wt% chromium, 10wt% nickel, 1.5wt% manganese, 0.2wt% aluminum, 0.7wt% cobalt, 0.32wt% titanium, and the rest is iron;

[0032] Step 2: Immerse the oven stainless steel substrate in the electrophoretic tank for electrophoretic deposition for 2 minutes, remove it, wash it, and dry it; then perform laser cladding and sinter it at 800°C for 3 hours to obtain oxidation-resistant high-strength stainless steel;

[0033] The raw materials of the electrophoresis tank liquid include the following components: 10 parts of modified nano zinc oxide, 100 parts of ethanol aqueous solution (the concentration of the ethanol aqueous solution is 80wt%), and 0.12 parts of KNO3;

[0034] The preparation method of modified nano zinc oxide comprises: adding N-aminoethyl-3-aminopropyltriethoxysilane to a 70wt% ethanol aqueous solution for 30 minutes to obtain a mixed solution; adding branched polysiloxane to a tetrahydrofuran aqueous solution containing NaOH (NaOH concentration is 0.02M, and the mass ratio of tetrahydrofuran to deionized water is 8:2), refluxing for 4 hours, cooling to room temperature, adjusting the pH to neutral, adding the mixed solution to uniformly mix, adjusting the pH to 6.5, adding nano zinc oxide-ethanol aqueous solution, stirring for 5 hours, filtering, washing, adding the solution to anhydrous ethanol, and Soxhlet extraction for 12 hours to obtain modified nano zinc oxide;

[0035] The mass ratio of N-aminoethyl-3-aminopropyltriethoxysilane, branched polysiloxane and nano zinc oxide is 0.3:0.6:2.5; N-aminoethyl-3-aminopropyltriethoxysilane accounts for 3wt% of the ethanol aqueous solution; the branched polysiloxane accounts for 5wt% of the tetrahydrofuran aqueous solution; and the nano zinc oxide accounts for 10wt% of the ethanol aqueous solution.

[0036] The process conditions of laser cladding are as follows: the cladding material includes nickel powder, nano-silicon dioxide, and nano-yttrium oxide in a mass ratio of 7:3:1, the overlap rate of laser scanning is 60%, the laser power is 2.2kW, and the scanning speed is 8mm / s.

[0037] Example 2, a method for preparing oxidation-resistant high-strength oven-use stainless steel, comprising the following steps:

[0038] Step 1: After melting iron at 1550°C, chromium, nickel, boron, manganese, aluminum, cobalt, and titanium are added, and the temperature is raised to 1650°C and smelted for 2 hours. The slag is removed to obtain molten steel, which is then cast into shape. The steel is then forged (initial forging at 1150°C, cumulative deformation of 60%, deformation of 30% per pass, final forging temperature of 900°C, and air cooling), hot rolled (start rolling temperature of 1050°C, final rolling temperature of 850°C, total reduction rate of 70%, and air cooling), and heat treated (holding at 1010°C for 2 hours, water quenching; holding at 900°C for 8 hours, and air cooling) to obtain an oven-safe stainless steel substrate.

[0039] The raw materials of the stainless steel substrate for ovens include the following components: 20wt% chromium, 10wt% nickel, 1.5wt% manganese, 0.2wt% aluminum, 0.7wt% cobalt, 0.32wt% titanium, and the rest is iron;

[0040] Step 2: Immerse the oven stainless steel substrate in the electrophoretic tank for electrophoretic deposition for 2 minutes, remove it, wash it, and dry it; then perform laser cladding and sinter it at 800°C for 3 hours to obtain oxidation-resistant high-strength stainless steel;

[0041] The raw materials of the electrophoresis tank liquid include the following components: 15 parts of modified nano zinc oxide, 100 parts of ethanol aqueous solution (the concentration of the ethanol aqueous solution is 80wt%), and 0.12 parts of KNO3;

[0042] The preparation method of modified nano zinc oxide comprises: adding N-aminoethyl-3-aminopropyltriethoxysilane to a 70wt% ethanol aqueous solution for 30 minutes to obtain a mixed solution; adding branched polysiloxane to a tetrahydrofuran aqueous solution containing NaOH (NaOH concentration is 0.02M, and the mass ratio of tetrahydrofuran to deionized water is 8:2), refluxing for 4 hours, cooling to room temperature, adjusting the pH to neutral, adding the mixed solution to uniformly mix, adjusting the pH to 6.5, adding nano zinc oxide-ethanol aqueous solution, stirring for 5 hours, filtering, washing, adding the solution to anhydrous ethanol, and Soxhlet extraction for 12 hours to obtain modified nano zinc oxide;

[0043] The mass ratio of N-aminoethyl-3-aminopropyltriethoxysilane, branched polysiloxane and nano zinc oxide is 0.3:0.6:2.5; N-aminoethyl-3-aminopropyltriethoxysilane accounts for 3wt% of the ethanol aqueous solution; the branched polysiloxane accounts for 5wt% of the tetrahydrofuran aqueous solution; and the nano zinc oxide accounts for 10wt% of the ethanol aqueous solution.

[0044] The process conditions of laser cladding are as follows: the cladding material includes nickel powder, nano-silicon dioxide, and nano-yttrium oxide in a mass ratio of 7:3:1, the overlap rate of laser scanning is 60%, the laser power is 2.2kW, and the scanning speed is 8mm / s.

[0045] Example 3, a method for preparing oxidation-resistant high-strength oven-use stainless steel, comprising the following steps:

[0046] Step 1: After melting iron at 1550°C, chromium, nickel, boron, manganese, aluminum, cobalt, and titanium are added, and the temperature is raised to 1650°C and smelted for 2 hours. The slag is removed to obtain molten steel, which is cast into shape. The steel is then forged (initial forging at 1150°C, cumulative deformation of 60%, deformation of each pass of 30%, final forging temperature of 900°C, and air cooling), hot rolled (start rolling temperature of 1050°C, final rolling temperature of 850°C, total reduction rate of 70%, and air cooling), and heat treated (holding at 1010°C for 2 hours, water quenching; holding at 900°C for 8 hours, and air cooling) to obtain an oven-safe stainless steel substrate.

[0047] The raw materials of the stainless steel substrate for ovens include the following components: 20wt% chromium, 12wt% nickel, 1.5wt% manganese, 0.2wt% aluminum, 0.7wt% cobalt, 0.32wt% titanium, and the rest is iron;

[0048] Step 2: Immerse the oven stainless steel substrate in the electrophoretic tank for electrophoretic deposition for 2 minutes, remove it, wash it, and dry it; then perform laser cladding and sinter it at 800°C for 3 hours to obtain oxidation-resistant high-strength stainless steel;

[0049] The raw materials of the electrophoresis tank liquid include the following components: 20 parts of modified nano zinc oxide, 100 parts of ethanol aqueous solution (the concentration of the ethanol aqueous solution is 80wt%), and 0.12 parts of KNO3, calculated by mass.

[0050] The preparation method of modified nano zinc oxide comprises: adding N-aminoethyl-3-aminopropyltriethoxysilane to a 70wt% ethanol aqueous solution for 30 minutes to obtain a mixed solution; adding branched polysiloxane to a tetrahydrofuran aqueous solution containing NaOH (NaOH concentration is 0.02M, and the mass ratio of tetrahydrofuran to deionized water is 8:2), refluxing for 4 hours, cooling to room temperature, adjusting the pH to neutral, adding the mixed solution to uniformly mix, adjusting the pH to 6.5, adding nano zinc oxide-ethanol aqueous solution, stirring for 5 hours, filtering, washing, adding the solution to anhydrous ethanol, and Soxhlet extraction for 12 hours to obtain modified nano zinc oxide;

[0051] The mass ratio of N-aminoethyl-3-aminopropyltriethoxysilane, branched polysiloxane and nano zinc oxide is 0.3:0.6:2.5; N-aminoethyl-3-aminopropyltriethoxysilane accounts for 3wt% of the ethanol aqueous solution; the branched polysiloxane accounts for 5wt% of the tetrahydrofuran aqueous solution; and the nano zinc oxide accounts for 10wt% of the ethanol aqueous solution.

[0052] The process conditions of laser cladding are as follows: the cladding materials include nickel powder, nano-silicon dioxide, and nano-yttrium oxide in a mass ratio of 7:3:2, the overlap rate of laser scanning is 60%, the laser power is 2.2 kW, and the scanning speed is 8 mm / s.

[0053] Comparative Example 1 is based on Example 3, using micron-sized silicon dioxide and yttrium oxide;

[0054] Step 1: After melting iron at 1550°C, chromium, nickel, boron, manganese, aluminum, cobalt, and titanium are added, and the temperature is raised to 1650°C and smelted for 2 hours. The slag is removed to obtain molten steel, which is cast into shape. The steel is then forged (initial forging at 1150°C, cumulative deformation of 60%, deformation of each pass of 30%, final forging temperature of 900°C, and air cooling), hot rolled (start rolling temperature of 1050°C, final rolling temperature of 850°C, total reduction rate of 70%, and air cooling), and heat treated (holding at 1010°C for 2 hours, water quenching; holding at 900°C for 8 hours, and air cooling) to obtain an oven-safe stainless steel substrate.

[0055] The raw materials of the stainless steel substrate for ovens include the following components: 20wt% chromium, 12wt% nickel, 1.5wt% manganese, 0.2wt% aluminum, 0.7wt% cobalt, 0.32wt% titanium, and the rest is iron;

[0056] Step 2: Immerse the oven stainless steel substrate in the electrophoretic tank for electrophoretic deposition for 2 minutes, remove it, wash it, and dry it; then perform laser cladding and sinter it at 800°C for 3 hours to obtain oxidation-resistant high-strength stainless steel;

[0057] The process conditions of laser cladding are as follows: the cladding materials include nickel powder, silicon dioxide (average particle size 3 μm), and yttrium oxide (average particle size 3 μm) in a mass ratio of 7:3:2, the overlap rate of laser scanning is 60%, the laser power is 2.2 kW, and the scanning speed is 8 mm / s.

[0058] Comparative Example 2 is based on Example 3, but without sintering treatment; the remaining steps are the same;

[0059] Step 1: After melting iron at 1550°C, chromium, nickel, boron, manganese, aluminum, cobalt, and titanium are added, and the temperature is raised to 1650°C and smelted for 2 hours. The slag is removed to obtain molten steel, which is cast into shape. The steel is then forged (initial forging at 1150°C, cumulative deformation of 60%, deformation of each pass of 30%, final forging temperature of 900°C, and air cooling), hot rolled (start rolling temperature of 1050°C, final rolling temperature of 850°C, total reduction rate of 70%, and air cooling), and heat treated (holding at 1010°C for 2 hours, water quenching; holding at 900°C for 8 hours, and air cooling) to obtain an oven-safe stainless steel substrate.

[0060] The raw materials of the stainless steel substrate for ovens include the following components: 20wt% chromium, 12wt% nickel, 1.5wt% manganese, 0.2wt% aluminum, 0.7wt% cobalt, 0.32wt% titanium, and the rest is iron;

[0061] Step 2: Immerse the oven stainless steel substrate in the electrophoretic tank liquid for electrophoretic deposition for 2 minutes, take it out, wash it, and dry it; then perform laser cladding to obtain oxidation-resistant high-strength stainless steel.

[0062] Comparative Example 3 was based on Example 3, except that electrophoretic deposition was not performed; the remaining steps were the same;

[0063] Step 1: After melting iron at 1550°C, chromium, nickel, boron, manganese, aluminum, cobalt, and titanium are added, and the temperature is raised to 1650°C and smelted for 2 hours. The slag is removed to obtain molten steel, which is cast into shape. The steel is then forged (initial forging at 1150°C, cumulative deformation of 60%, deformation of each pass of 30%, final forging temperature of 900°C, and air cooling), hot rolled (start rolling temperature of 1050°C, final rolling temperature of 850°C, total reduction rate of 70%, and air cooling), and heat treated (holding at 1010°C for 2 hours, water quenching; holding at 900°C for 8 hours, and air cooling) to obtain an oven-safe stainless steel substrate.

[0064] The raw materials of the stainless steel substrate for ovens include the following components: 20wt% chromium, 12wt% nickel, 1.5wt% manganese, 0.2wt% aluminum, 0.7wt% cobalt, 0.32wt% titanium, and the rest is iron;

[0065] Step 2: Laser cladding the oven stainless steel substrate and sintering it at 800°C for 3 hours to obtain oxidation-resistant high-strength stainless steel;

[0066] The process conditions of laser cladding are as follows: the cladding materials include nickel powder, nano-silicon dioxide, and nano-yttrium oxide in a mass ratio of 7:3:2, the overlap rate of laser scanning is 60%, the laser power is 2.2 kW, and the scanning speed is 8 mm / s.

[0067] Comparative Example 4 is based on Example 3, except that a phenyl group is introduced into the branched polysiloxane; the remaining steps are the same;

[0068] Step 1: After melting iron at 1550°C, chromium, nickel, boron, manganese, aluminum, cobalt, and titanium are added, and the temperature is raised to 1650°C and smelted for 2 hours. The slag is removed to obtain molten steel, which is cast into shape. The steel is then forged (initial forging at 1150°C, cumulative deformation of 60%, deformation of each pass of 30%, final forging temperature of 900°C, and air cooling), hot rolled (start rolling temperature of 1050°C, final rolling temperature of 850°C, total reduction rate of 70%, and air cooling), and heat treated (holding at 1010°C for 2 hours, water quenching; holding at 900°C for 8 hours, and air cooling) to obtain an oven-safe stainless steel substrate.

[0069] Step 2: Immerse the oven stainless steel substrate in the electrophoretic tank for electrophoretic deposition for 2 minutes, remove it, wash it, and dry it; then perform laser cladding and sinter it at 800°C for 3 hours to obtain oxidation-resistant high-strength stainless steel;

[0070] The preparation method of branched polysiloxane is as follows: (1) adding 0.18 parts of vinyl-terminated polydimethylsiloxane to 10 parts of toluene and mixing uniformly, adding 0.08 parts of Karstedt catalyst and mixing uniformly, heating to 50°C under nitrogen protection, adding trimethoxysilane-toluene solution (0.3 parts of trimethoxysilane, 10 parts of toluene), stirring for 8 hours, heating to 60°C, adding activated carbon and continuing stirring for 0.5 hours, immediately cooling to room temperature, filtering, and rotary evaporating the liquid to remove the solvent to obtain silane monomer; (2) weighing acetic anhydride, silane monomer, and phenyltrimethoxysilane in a molar ratio of 1.5:1:0.2; uniformly mixing the silane monomer and acetic anhydride, adding 0.15 parts of tetrakis(trimethylsiloxy)titanium, heating to 60°C under nitrogen atmosphere, vacuuming for 3 hours, adding acetoxypropyltrimethoxysilane and mixing uniformly, and continuing vacuuming for 3 hours to obtain branched polysiloxane.

[0071] Testing experiment: (1) The oxidation-resistant high-strength stainless steel obtained in Examples 1 to 3 was tested for tensile strength on a WDW-300E tensile testing machine at room temperature;

[0072] (2) The oxidation-resistant high-strength stainless steel obtained in Example 2 and Comparative Examples 1 to 4 was placed in a resistance furnace, oxidized continuously at 800°C for 150 hours, and then air-cooled; the oxidation weight gain data (mg / cm 2 );

[0073] Table 1

[0074] ;

[0075] Table 2

[0076]

[0077] Conclusion: Comparative Example 1 is based on Example 3, using micron-sized silica and yttrium oxide; as a result, during the laser cladding process, micron-sized silica and yttrium oxide affect the filling of the pores, resulting in a decrease in density and high-temperature stability, thereby reducing the performance of Comparative Example 1; Comparative Example 2 is based on Example 3, without sintering treatment; as a result, the pores in the laser cladding process are not eliminated, thereby reducing the performance of Comparative Example 2; Comparative Example 3 is based on Example 3, without electrophoretic deposition; as a result, the interface bonding is reduced, and cracks appear during the laser cladding process, thereby reducing the performance of Comparative Example 3; Comparative Example 4 is based on Example 3, introducing phenyl groups into the branched polysiloxane; the remaining steps are the same; due to the stability of the benzene ring, the conversion of the branched polysiloxane into silica is affected during the laser cladding process, thereby reducing the performance of Comparative Example 4.

[0078] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for preparing oxidation-resistant high-strength oven stainless steel, characterized by: The following steps are included: Step 1: After melting iron at 1550-1600°C, add chromium, nickel, manganese, aluminum, cobalt, and titanium, heat it to 1650-1700°C and smelt it for 1.5-2 hours, remove the slag, and obtain molten steel; cast it into shape, and then perform forging, hot rolling, and heat treatment in sequence to obtain a stainless steel substrate for oven use; Step 2: Immerse the stainless steel substrate for the oven in the electrophoresis tank for electrophoretic deposition for 2 to 3 minutes, remove it, wash it, and dry it; Then laser cladding and sintering are performed to obtain oxidation-resistant high-strength stainless steel; The raw materials of the electrophoresis tank liquid include the following components: 10-20 parts of modified nano zinc oxide, 90-100 parts of ethanol aqueous solution, and 0.1-0.13 parts of KNO3, by weight; the concentration of the ethanol aqueous solution is 70-80wt%; The preparation method of the modified nano zinc oxide comprises: adding N-aminoethyl-3-aminopropyltriethoxysilane to an ethanol aqueous solution for 30 to 40 minutes to obtain a mixed solution; adding branched polysiloxane to a tetrahydrofuran aqueous solution containing NaOH, refluxing for 4 to 5 hours, cooling to room temperature, adjusting the pH to neutral, adding the mixed solution and uniformly mixing, adjusting the pH to 6 to 6.5, adding the nano zinc oxide-ethanol aqueous solution, stirring for 4 to 6 hours, filtering, washing, adding the solution to anhydrous ethanol, and performing Soxhlet extraction for 10 to 15 hours to obtain the modified nano zinc oxide; The mass ratio of the N-aminoethyl-3-aminopropyltriethoxysilane, the branched polysiloxane, and the nano-zinc oxide is (0.2-0.4):(0.5-0.7):(2-3); the N-aminoethyl-3-aminopropyltriethoxysilane accounts for 2-4wt% of the ethanol aqueous solution; the branched polysiloxane accounts for 5-8wt% of the tetrahydrofuran aqueous solution; the nano-zinc oxide accounts for 7-10wt% of the ethanol aqueous solution; the concentration of the ethanol aqueous solution is 70-80wt%; in the tetrahydrofuran aqueous solution, the NaOH concentration is 0.01-0.03M, and the mass ratio of tetrahydrofuran to deionized water is (7-8):2; The preparation method of the branched polysiloxane is as follows: (1) vinyl-terminated polydimethylsiloxane is added to toluene and mixed uniformly, Karstedt catalyst is added and mixed uniformly, the temperature is raised to 50-55°C under nitrogen protection, trimethoxysilane-toluene solution is added, stirring is performed for 8-10 hours, the temperature is raised to 60-65°C, activated carbon is added and stirring is continued for 0.5-1 hour, the temperature is immediately cooled to room temperature, filtered, and the liquid is rotary evaporated to remove the solvent to obtain a silane monomer; (2) the silane monomer and acetic anhydride are uniformly mixed, tetrakis(trimethylsiloxy)titanium is added, the temperature is raised to 55-60°C under nitrogen atmosphere, vacuum is applied for 3-4 hours, acetoxypropyltrimethoxysilane is added and mixed uniformly, and vacuum is applied for 3-4 hours to obtain a branched polysiloxane.

2. The method for preparing oxidation-resistant high-strength stainless steel for oven use according to claim 1, characterized in that: The raw materials of the stainless steel substrate for the oven include the following components: 16-20 wt% chromium, 8-12 wt% nickel, 1-2 wt% manganese, 0.1-0.3 wt% aluminum, 0.5-1.5 wt% cobalt, 0.32-0.45 wt% titanium, and the rest is iron.

3. The method for preparing oxidation-resistant high-strength stainless steel for oven use according to claim 1, characterized in that: The raw materials of the silane monomer include the following components: 0.18-0.3 parts of vinyl-terminated polydimethylsiloxane, 0.25-0.35 parts of trimethoxyhydrosilane, 0.08-0.12 parts of Karstedt catalyst, and 50-60 parts of toluene, calculated by mass; the molar ratio of the acetic anhydride, silane monomer, and acetoxypropyltrimethoxysilane is 1.5:1:(0.2-0.3).

4. The method for preparing oxidation-resistant high-strength stainless steel for oven use according to claim 1, characterized in that: The process conditions for electrophoretic deposition are as follows: the pH of the electrophoretic bath liquid is 6-7, the temperature is 25-35°C, and the pulse voltage is 80-100V; the process conditions for laser cladding are as follows: the cladding material includes nickel powder, nano-silicon dioxide, and nano-yttrium oxide in a mass ratio of 7:3:(1-2), the overlap rate of laser scanning is 50-60%, the laser power is 2.2-2.4kW, and the scanning speed is 6-8mm / s; the process conditions for sintering treatment are as follows: the temperature is 700-800°C and the time is 2-3 hours.

5. The method for preparing oxidation-resistant high-strength oven stainless steel according to claim 1, characterized in that: The forging process conditions are as follows: initial forging temperature of 1100-1200° C., cumulative deformation of 60-70%, deformation of 30%-40% per pass, final forging temperature of 900-1000° C., and air cooling; the hot rolling process conditions are as follows: starting rolling temperature of 1050-1150° C., final rolling temperature of 800-900° C., total reduction rate of 70-80%, and air cooling; and the heat treatment process conditions are as follows: holding at 1010-1150° C. for 1-2 hours, water quenching; holding at 850-950° C. for 8-10 hours, and air cooling.

6. The method for preparing oxidation-resistant high-strength stainless steel for oven use according to any one of claims 1 to 5 is used to prepare oxidation-resistant high-strength stainless steel.

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