Alloy stainless steel and application method thereof in beer barrel pressure divider casting

Abstract

The invention provides alloy stainless steel and an application method thereof in beer barrel voltage divider casting, and the method comprises the following steps: determining that the molar ratio of Nb to C is greater than 8 according to the alloy stainless steel, and fixing carbon and nitrogen elements by forming niobium carbide and niobium nitride; the alloy stainless steel is adopted for preparing the beer barrel voltage divider, and the alloy stainless steel is treated through a precision casting method to form the beer barrel voltage divider; the beer barrel pressure divider is smelted and poured through the precision casting method, and a poured mold shell is obtained and subjected to annealing treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of information technology, and particularly relates to an alloy stainless steel and an application method thereof in beer barrel pressure divider casting. BACKGROUND

[0002] The field of beer equipment manufacturing involves a large number of metal components that directly contact liquid media, which need to have excellent corrosion resistance, high strength and low production cost at the same time to ensure long-term stable operation of the equipment and reduce operating costs.

[0003] The current common metal component manufacturing method mostly uses a single alloy formula or a traditional casting process, which can basically meet the basic needs, but often exposes prominent problems on complex structural parts. For example, although high-nickel alloy has strong corrosion resistance, the overall cost is high due to the high price of raw materials, and low-cost alternative alloys are prone to cause uneven organization in the casting process due to unstable composition, further amplifying the corrosion risk and strength deficiency. These defects repeatedly occur in actual production, but it is difficult to be completely solved by simple adjustment.

[0004] In the production of beer barrel pressure dividers and other complex structural components, the most core technical difficulty lies in the control of the precipitation stability of carbon and nitrogen elements. Because the internal channels of the pressure divider are curved and interlaced, the flow of molten metal is complex during casting. If the carbon and nitrogen elements cannot be uniformly and stably precipitated, the precipitates will accumulate or be missing in local areas, forming uneven microstructure, which directly causes casting defects such as shrinkage and cold shut. For example, during pouring, the metal enters the bend from the inlet, the local cooling is too fast, the precipitates abnormally accumulate to form micro pores on the channel wall, and the other side appears cold shut cracks due to cooling lag. These defects accumulate to make the surface of the component rough, the internal strength unstable, and further accelerate the corrosion and perforation in the beer acid environment.

[0005] Therefore, how to realize stable precipitation of carbon and nitrogen elements under the condition of low nickel content to eliminate casting defects, while considering corrosion resistance and high strength, has become a key problem to ensure efficient manufacturing of beer barrel pressure dividers.

[0006] This problem not only affects the qualification rate of the pressure divider alone, but also directly restricts the continuous production of the entire beer equipment assembly line. Because once the internal micro pores of the component are enlarged during operation, it may cause beer leakage or pressure loss of control, forcing the production line to frequently stop for maintenance, thereby increasing the overall manufacturing cost and delaying the delivery deadline. SUMMARY

[0007] The application provides an alloy stainless steel, which comprises the following chemical components in percentage by mass: C is 0.05-0.08, Si is 0.3-2.00, Mn is 0.55-1.50, P is 0.020-0.045, S is 0.010-0.020, Cr is 17.0-19.0, Ni is 0.30-0.70, Nb is 0.30-0.60, N is 0.020-0.050, and the balance is Fe.

[0008] The application further provides an application method of the alloy stainless steel in beer barrel pressure divider casting.

[0009] The alloy stainless steel material is obtained, and the alloy stainless steel comprises the following chemical components in percentage by mass: C is 0.05-0.08, Si is 0.3-2.00, Mn is 0.55-1.50, P is 0.020-0.045, S is 0.010-0.020, Cr is 17.0-19.0, Ni is 0.30-0.70, Nb is 0.30-0.60, N is 0.020-0.050, and the balance is Fe; the mole ratio of Nb and C in the alloy stainless steel is greater than 8, carbon and nitrogen elements are fixed by forming niobium carbide and niobium nitride; the alloy stainless steel is used to prepare a beer barrel pressure divider, the alloy stainless steel is treated by a precision casting method to form the beer barrel pressure divider; the beer barrel pressure divider is smelted and poured by the precision casting method, and a poured mold shell is obtained and subjected to annealing treatment.

[0010] Further, the alloy stainless steel material comprises: the optimized alloy stainless steel is obtained by adjusting the C content in the alloy stainless steel to be lower than 0.03 and the Si content to be lower than 1.00; the further optimized alloy stainless steel is obtained by adjusting the Mn content to be lower than 1.00 and the P content to be lower than 0.040 according to the optimized alloy stainless steel; the S content is set to be lower than 0.015 and the Cr content is 18, the Ni content is set to be lower than 0.50 and the Nb content is 0.40 by the further optimized alloy stainless steel; the N content is adjusted to be lower than 0.030 and the balance is Fe according to the further optimized alloy stainless steel, so that the final alloy stainless steel material is obtained; the mole ratio of Nb and C is greater than 8 by the final alloy stainless steel material, and the carbon element is fixed to prevent the precipitation of chromium carbide and optimize the solidification process.

[0011] Further, the molar ratio of Nb to C is greater than 8, including: obtaining a niobium carbide formation condition by the molar ratio of Nb to C being greater than 8, determining a niobium nitride generation path; fixing carbon elements according to the niobium carbide formation condition, obtaining a nitrogen element fixation result; refining the grain structure through the nitrogen element fixation result, determining the corrosion resistance performance improvement; optimizing the high temperature strength according to the corrosion resistance performance improvement, obtaining the creep resistance performance data; improving the toughness and the welding performance through the creep resistance performance data, determining the stability of the alloy stainless steel in casting.

[0012] Further, the beer barrel pressure divider prepared by the alloy stainless steel, including: preparing a wax mold by the alloy stainless steel, obtaining a wax mold structure; making a ceramic shell according to the wax mold structure, determining a ceramic shell firing parameter; performing melting and pouring through the ceramic shell firing parameter, obtaining a pouring mold shell; performing cutting and cleaning according to the pouring mold shell, determining a heat treatment condition; processing the surface through the heat treatment condition, obtaining a machining object; detecting and packaging according to the machining object, determining the air tightness of the beer barrel pressure divider.

[0013] Further, the precision casting method, including: setting a firing temperature range when making a ceramic shell by the precision casting method, obtaining a firing time setting; enhancing the strength of the ceramic shell according to the firing time setting, determining a casting defect reduction path; optimizing the melting temperature through the casting defect reduction path, obtaining a refining standing time; adjusting the pouring temperature according to the refining standing time, determining the interval time from taking out the mold shell to pouring; controlling the mold shell to keep in a high temperature state through the interval time, obtaining a cold separation defect reduction result; verifying the annealing treatment after pouring according to the cold separation defect reduction result, determining the grain refinement effect.

[0014] Further, the melting and pouring, including: setting a refining temperature range by the melting and pouring, obtaining a refining standing time interval; determining a pouring temperature range according to the refining standing time interval, obtaining a mold shell taking out interval control; performing high temperature pouring if the interval is less than a preset threshold value through the mold shell taking out interval control, determining defect minimization; obtaining a pouring mold shell according to the defect minimization, determining an annealing holding temperature; performing a furnace cooling process through the annealing holding temperature, obtaining an air cooling result; verifying the microstructure improvement according to the air cooling result, determining the precipitated phase reduction.

[0015] Further, the obtaining the casted shell and performing annealing treatment comprises: determining an annealing initial temperature through the casted shell, obtaining a holding time setting; performing furnace cooling to a specified temperature according to the holding time setting, determining an out-of-furnace air cooling path; refining grains through the out-of-furnace air cooling path, obtaining columnar grain control; reducing point-like precipitated phases according to the columnar grain control, determining ferrite matrix optimization; verifying grain grade through the ferrite matrix optimization, obtaining coarse grain suppression result; improving beer keg pressure reducer quality according to the coarse grain suppression result, and determining Nb oxidation problem solution.

[0016] The technical scheme provided by the embodiment of the application can include the following beneficial effects:

[0017] Through the above-mentioned comprehensive optimization, the application solves the business problems of beer keg pressure reducers, such as easy casting defects, corrosion resistance and cost sensitivity under complex structure, the core of which is the design of the Nb and C molar ratio greater than 8, which ensures the stable precipitation of carbon and nitrogen elements, avoids the decrease of corrosion resistance, and at the same time, the low nickel content reduces the cost and forms a dual-phase structure to improve the strength; the precision casting process effectively eliminates defects such as shrinkage and cold shut through high-temperature smooth casting and directional solidification, and the annealing treatment further optimizes the uniformity of the structure, finally realizing a high-quality pressure reducer with smooth surface and no internal defects, meeting the long-term stable operation demand of beer equipment. The overall technical effect significantly improves the corrosion resistance and mechanical properties of the pressure reducer, reduces the material cost by about 30%, guarantees efficient and high-precision manufacturing, and promotes the development of beer equipment production towards high quality and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A flowchart of an alloy stainless steel and its application method in beer keg pressure reducer casting. DETAILED DESCRIPTION

[0019] In order to further understand the content of the application, the application will be described in detail in conjunction with the drawings and embodiments. The specific embodiments described herein are only used to explain the related application, and are not a limitation of the application. In addition, it should be noted that, in order to facilitate description, only the parts related to the application are shown in the drawings.

[0020] Embodiment 1

[0021] The alloy stainless steel according to the embodiment includes the following chemical components in percentage by mass: C is 0.05-0.08, Si is 0.3-2.00, Mn is 0.55-1.50, P is 0.020-0.045, S is 0.010-0.020, Cr is 17.0-19.0, Ni is 0.30-0.70, Nb is 0.30-0.60, N is 0.020-0.050, and the balance is Fe.

[0022] Embodiment 2

[0023] As Figure 1 The application method of the alloy stainless steel in the casting of the beer barrel pressure divider can specifically include the following steps.

[0024] The embodiment of the application provides an alloy stainless steel and an application method of the alloy stainless steel in the casting of a beer barrel pressure divider.

[0025] In step S1, an alloy stainless steel material is obtained, and the alloy stainless steel includes C is 0.05-0.08, Si is 0.3-2.00, Mn is 0.55-1.50, P is 0.020-0.045, S is 0.010-0.020, Cr is 17.0-19.0, Ni is 0.30-0.70, Nb is 0.30-0.60, N is 0.020-0.050, and the balance is Fe.

[0026] In an embodiment, the content of each element of the alloy stainless steel material needs to be strictly controlled. The content of carbon element is controlled in the range of 0.05-0.08 mass percent, which can ensure that the alloy has sufficient strength, and avoid the problem of chromium carbide precipitation caused by excessive carbon element. Silicon element is used as a deoxidizer and alloying element, and the content of silicon element is set to 0.3-2.00 mass percent. A lower silicon content can help to improve the casting performance of the alloy, and an appropriate silicon content can improve the oxidation resistance of the alloy. The content of manganese element is controlled in the range of 0.55-1.50 mass percent. Manganese element mainly plays a role in deoxidation and desulfurization, and can refine the grain structure and improve the comprehensive mechanical properties of the alloy.

[0027] Specifically, the content of phosphorus element is strictly limited in the range of 0.020-0.045 mass percent. Although phosphorus element can improve the strength and hardness of the alloy, excessive phosphorus will cause hot brittleness problem, affecting the plastic deformation ability of the alloy at high temperature. The content of sulfur element is controlled in the range of 0.010-0.020 mass percent. The presence of sulfur element will form sulfide inclusions, reducing the toughness and corrosion resistance of the alloy, so its content needs to be strictly controlled. Chromium element is the main alloying element of stainless steel, and its content is set to 17.0-19.0 mass percent. This content range can ensure that the alloy has excellent corrosion resistance, while avoiding the problem of excessive ferrite phase caused by excessive chromium element.

[0028] In one possible implementation, the content of nickel element is controlled in the range of 0.30-0.70 mass percent. Compared with traditional austenitic stainless steel, the alloy adopts a lower nickel content design, which not only reduces the material cost, but also can obtain a ferrite-austenite dual-phase structure. The content of niobium element is set to 0.30-0.60 mass percent. Niobium element is a key alloying element of the alloy, which can form stable niobium carbide and niobium nitride precipitates with carbon and nitrogen, effectively fixing free carbon and nitrogen elements. The content of nitrogen element is controlled in the range of 0.020-0.050 mass percent. Appropriate amount of nitrogen element can improve the strength and corrosion resistance of the alloy, but excessive nitrogen will cause casting defects such as porosity.

[0029] It should be noted that the balance is iron element. As a base element, the content of iron element is indirectly determined by controlling the content of other alloying elements. In actual production, the selection and proportioning calculation of raw materials need to consider the interaction between elements and the burning loss. For example, during the melting process, carbon element will be oxidized and cause a certain amount of burning loss, so the addition amount of carbon element needs to be appropriately increased during batching. Silicon element and manganese element will also be oxidized and burned during high-temperature melting process, and need to be compensated according to the actual melting conditions and equipment characteristics.

[0030] Step S2, according to the alloy stainless steel, the molar ratio of Nb to C is greater than 8, and the carbon and nitrogen elements are fixed by forming niobium carbide and niobium nitride.

[0031] Exemplarily, the molar ratio control of niobium to carbon is the core technical point of the alloy design. When the molar ratio of niobium to carbon is greater than 8, it can ensure that the carbon element in the alloy preferentially combines with niobium to form niobium carbide precipitates, rather than combining with chromium to form chromium carbide. The formation of chromium carbide will consume the chromium element in the matrix, causing the appearance of chromium-depleted regions, which seriously affects the corrosion resistance of the alloy. By controlling the molar ratio of niobium to carbon, this problem can be effectively avoided.

[0032] In one embodiment, the formation process of niobium carbide involves complex thermodynamic and kinetic mechanisms. During the alloy solidification process, the solubility of carbon elements gradually decreases as the temperature decreases, and the carbide phase begins to precipitate. Because the binding ability of niobium and carbon is stronger than that of chromium and carbon, when the niobium content is sufficient, carbon elements will preferentially combine with niobium to form niobium carbide. Niobium carbide has a face-centered cubic structure, and has good lattice matching with the matrix, which can refine the grains and strengthen the matrix.

[0033] Specifically, the formation mechanism of niobium nitride is similar to that of niobium carbide. Nitrogen has a high solubility at high temperatures, but as the temperature decreases, the solubility of nitrogen decreases sharply, making it easy to form nitride precipitates. Niobium elements can combine with nitrogen elements to form stable niobium nitride, effectively fixing free nitrogen elements. Niobium nitride has a hexagonal close-packed structure, is small in size and uniformly distributed, and can significantly improve the strength and hardness of the alloy.

[0034] In one possible implementation, the molar ratio of niobium to carbon and nitrogen needs to consider the content of both elements. Assuming that the carbon content in the alloy is 0.06 mass percent, the nitrogen content is 0.03 mass percent, and the niobium content is 0.45 mass percent, the molar ratio of niobium to total carbon and nitrogen can be calculated to be about 9.2 by molar mass conversion, which meets the design requirement of greater than 8. This molar ratio can ensure that the carbon and nitrogen elements in the alloy are fully fixed, avoiding the precipitation of harmful phases during subsequent heat treatment and use.

[0035] It should be noted that the addition of niobium elements can also improve the high-temperature performance of the alloy. The niobium carbide and niobium nitride precipitates have good thermal stability and are not prone to coarsening and dissolution at high temperatures, which can maintain the strengthening effect on the matrix for a long time. This is of great significance for beer keg pressure regulators and other devices that need to work at a certain temperature for a long time.

[0036] Step S3, using the alloy stainless steel to prepare a beer keg pressure regulator, and processing the alloy stainless steel by a precision casting method to form the beer keg pressure regulator.

[0037] In one embodiment, the precision casting method is a key process technology for preparing a beer keg pressure regulator. Precision casting, also known as investment casting, is a casting method that can obtain precise dimensions and smooth surfaces. This method is particularly suitable for manufacturing parts with complex shapes and high dimensional accuracy. As an important part of beer equipment, the beer keg pressure regulator has a complex internal flow channel and high surface quality requirements, and traditional mechanical processing methods cannot meet its manufacturing requirements.

[0038] Specifically, the process flow of precision casting method includes multiple steps such as wax mold making, shell making, dewaxing, baking, pouring, cleaning, etc. First of all, an accurate wax mold needs to be made, and the dimensional accuracy of the wax mold directly affects the quality of the final casting. The wax mold material is usually a mixture of paraffin and stearic acid, and the molten wax is injected into the metal mold through the wax injection machine. The wax mold making needs to strictly control the wax injection temperature and pressure to ensure the dimensional accuracy and surface quality of the wax mold.

[0039] Exemplarily, the shell making process is the core link of precision casting. The shell making process includes steps such as applying refractory coating and spreading quartz sand, and needs to be repeated multiple times to obtain a shell with sufficient thickness and strength. The first layer of coating is usually made of fine-grained zirconium sand and silica sol, which can obtain a smooth casting surface. Subsequent layers of coating gradually use coarser-grained quartz sand to improve the permeability and strength of the shell. Each layer of coating needs to be dried in a controlled temperature and humidity environment after being applied to ensure the uniformity and bonding strength of the coating.

[0040] In one possible implementation, the dewaxing and baking processes have an important influence on the quality of the casting. The dewaxing process needs to heat the shell to 150-200 degrees Celsius to completely melt the wax mold and flow out of the shell. If the dewaxing temperature is too low, the wax will remain, affecting the surface quality of the casting; if the dewaxing temperature is too high, the shell may crack. The baking process is to sinter the dewaxed shell at high temperature to improve the strength and refractory performance of the shell. The baking temperature is usually controlled at 900-1000 degrees Celsius, and the baking time is determined according to the thickness of the shell, usually 2-4 hours.

[0041] It should be noted that the precision casting of alloy stainless steel puts special requirements on the pouring process. Due to the high melting point of stainless steel, the fluidity is relatively poor, and a higher pouring temperature and appropriate pouring system design are needed. The pouring temperature is usually controlled at 1580-1620 degrees Celsius, and a lower pouring temperature will cause poor filling and cold shut defects, and a higher pouring temperature will exacerbate the thermal chemical reaction of the shell, affecting the surface quality of the casting. The design of the pouring system needs to consider the flow characteristics and solidification characteristics of the metal liquid, and reasonably set the size and position of the sprue, runner and cross runner.

[0042] In one embodiment, the structural characteristics of the beer barrel pressure divider pose special challenges to the precision casting process. The pressure divider has a complex flow channel and cavity structure inside, which is prone to shrinkage and porosity defects during casting. In order to solve this problem, the solidification sequence and feeding path of the metal liquid need to be fully considered in the wax mold design stage. By reasonably setting the riser and chill, directional solidification can be achieved to avoid shrinkage defects. At the same time, the thin-walled parts of the pressure divider are prone to cold shut and underfill defects, which need to be solved by optimizing the pouring system and increasing the pouring temperature.

[0043] Specifically, the surface quality of the pressure divider requires extremely high, and surface defects such as pores, inclusions, cold shut and the like are not allowed. This requires strict control of the quality of each process in the precision casting process. The permeability of the shell needs to be moderate, which can ensure the smooth discharge of gas when the metal liquid fills the mold, and prevent the metal liquid from penetrating into the shell to cause sand sticking defects. The alloy smelting process needs to be fully deoxidized and degassed to avoid the formation of oxide inclusions and pores. During pouring, the metal liquid should be kept flowing smoothly to avoid gas entrapment and oxidation.

[0044] Step S4, smelting and pouring the beer barrel pressure divider by the precision casting method, obtaining the poured mold shell and performing annealing treatment.

[0045] In an embodiment, the smelting process is a key link to ensure the accuracy of alloy composition and the quality of the metal liquid. The smelting process is carried out by using a medium-frequency induction furnace, and the furnace charge ratio needs to be accurately calculated according to the target composition and the burning loss rate of each element. First, scrap steel and iron materials are added as basic raw materials into the furnace and are preliminarily melted at 1400-1450 degrees Celsius. Subsequently, alloying elements such as chromium iron, nickel plate, and niobium iron are added in the calculated ratio. The feeding sequence needs to consider the melting point and oxidation tendency of each element, and high-melting-point elements are added first, and easily oxidized elements are added in a reducing atmosphere.

[0046] Specifically, the timing of adding niobium iron has an important influence on the control of alloy composition. Niobium element is easy to combine with oxygen to form niobium oxide at high temperature, which reduces the effective niobium content. Therefore, the addition of niobium iron needs to be carried out when the metal liquid temperature is relatively low and the furnace atmosphere is reducing. Generally, niobium iron is added when the metal liquid temperature drops to about 1500 degrees Celsius, and an appropriate amount of aluminum particles are added as a deoxidizer to ensure the yield of niobium element. After adding niobium iron, it needs to be fully stirred to make it uniformly distributed in the metal liquid, and the stirring time is generally 8-10 minutes.

[0047] Exemplarily, the deoxidation and desulfurization treatment in the smelting process has a decisive influence on the quality of the final casting. The deoxidation treatment adopts the method of combining aluminum deoxidation and silicon-manganese deoxidation, first adding aluminum particles for preliminary deoxidation, and the addition amount of aluminum is calculated according to 0.3-0.5 kilograms per ton of the weight of the metal liquid. Aluminum deoxidation reaction is violent, which can quickly reduce the oxygen content in the metal liquid, but will produce aluminum oxide inclusions. Subsequently, silicon-manganese alloy is added for fine deoxidation, and the silicon and manganese elements in the silicon-manganese alloy can further reduce the oxygen content, and the oxides generated have small density and can easily float and be removed.

[0048] In one possible implementation, the desulfurization treatment adopts a calcium treatment technology. A calcium-silicon alloy is added to the molten metal, and calcium combines with sulfur to form calcium sulfide, which has a high melting point and a small density and exists in the molten metal in the form of solid inclusions, which can be effectively removed through standing and slagging. The amount of calcium added needs to be determined according to the sulfur content in the molten metal, and is generally calculated according to a calcium-sulfur molar ratio of 2-3 times. After calcium treatment, the molten metal needs to be stood for 15-20 minutes to allow the calcium sulfide inclusions to fully float and gather.

[0049] It should be noted that the standing time of the molten metal during refining has an important influence on the inclusion removal effect. During the standing process, oxide and sulfide inclusions with a smaller density gradually float to the surface of the molten metal to form a slag layer. If the standing time is too short, the inclusions will not be removed sufficiently, which will affect the mechanical properties and surface quality of the castings. If the standing time is too long, the temperature of the molten metal will be excessively reduced, which will affect the fluidity during pouring. According to the furnace capacity and the depth of the molten metal, the standing time is generally controlled to be 20-30 minutes.

[0050] In one embodiment, the control of the pouring temperature is a key parameter to ensure the quality of the castings. If the pouring temperature is too high, it will intensify the chemical reaction between the molten metal and the mold shell, resulting in sand sticking and penetration defects, and will also increase the shrinkage stress of the castings. If the pouring temperature is too low, it will result in insufficient fluidity of the molten metal, causing cold shut, underfilling and other defects. For this alloy stainless steel, the optimal pouring temperature range is 1580-1620 degrees Celsius. Before pouring, an infrared temperature measuring instrument needs to be used to accurately measure the temperature of the molten metal, to ensure that the temperature control accuracy is within ±10 degrees Celsius.

[0051] Specifically, the pouring process needs to maintain the smooth flow of the molten metal to avoid turbulence and air entrainment. The control of the pouring speed needs to be determined according to the wall thickness and complexity of the castings. For thin-walled and complex castings such as beer barrel pressure dividers, the initial pouring speed should be relatively fast to ensure that the molten metal can quickly fill all parts of the mold cavity, avoiding poor filling due to temperature reduction. When the molten metal fills 70-80% of the mold cavity, the pouring speed should be appropriately reduced to reduce the impact on the mold shell and avoid damage to the mold shell and splashing of the molten metal.

[0052] Illustratively, the control of the timing of the removal of the mold shell is of great significance to avoid cold shut defects. After the mold shell is removed from the baking furnace, its temperature will rapidly decrease. If the interval between the removal of the mold shell and the pouring is too long, the low temperature of the mold shell will cause the molten metal to rapidly cool during the filling process, resulting in cold shut defects. The ideal temperature of the mold shell should be maintained at 800-900 degrees Celsius, which requires that the pouring should be completed within 5-8 minutes after the mold shell is removed. In order to ensure the accuracy of the time control, the time nodes of the melting and baking processes need to be reasonably arranged to ensure that the two processes can effectively connect.

[0053] For example, the following test was conducted:

[0054] Pouring temperature Waiting time Cold shut Scheme one (32 pieces) 1642℃ 12s 6(18.75％) Scheme two (32 pieces) 1617℃ 6s 2(6.25％) Scheme three (32 pieces) 1617℃ 12s 8(25％) Mass production process 1640±10℃ ＜10s

[0055] From the above table, it can be concluded that the shorter the pouring time of the beer barrel pressure divider mold shell, the higher the mold shell temperature, the more conducive to reducing the cold separation.

[0056] In one possible implementation, the cooling process after pouring has an important influence on the microstructure of the casting. The cooling speed of the casting in the shell is relatively slow, which is beneficial to reducing casting stress and avoiding the generation of cracks. However, too slow cooling speed will lead to coarse grains and the precipitation of harmful phases, affecting the mechanical properties of the casting. By controlling the thickness and permeability of the shell, the cooling speed of the casting can be adjusted. For parts with large wall thickness, the shell thickness can be appropriately increased to slow down the cooling speed and avoid shrinkage defects. For parts with thin wall thickness, the shell thickness can be reduced or the permeability can be increased to speed up the cooling speed and refine the grain structure.

[0057] It should be noted that annealing treatment is an important process for improving the microstructure of the casting and eliminating casting stress. During the solidification process, the casting will generate a large thermal stress and organizational stress, which will cause deformation or cracking of the casting if not eliminated in time. Annealing treatment heats the casting to an appropriate temperature and keeps it for a certain period of time, so that the internal stress is released and the microstructure is improved. The selection of annealing temperature needs to consider the phase change characteristics of the alloy and the stability of the precipitated phase. If the temperature is too low, the stress relief effect cannot be achieved, and if the temperature is too high, the grains may be coarsened or harmful phases may be precipitated.

[0058] In one embodiment, the determination of annealing process parameters needs to consider the size, shape and alloy characteristics of the casting. For a casting with complex shape such as a beer barrel pressure divider, the annealing temperature is usually set at 1050-1100 degrees Celsius. This temperature range can effectively eliminate the casting stress and avoid excessive grain growth. The holding time is determined according to the maximum wall thickness of the casting, generally calculated at 1-2 minutes per millimeter of wall thickness. For a casting with a wall thickness of 10 millimeters, the holding time should be not less than 20 minutes.

[0059] Specifically, the control of the heating rate during annealing is of great significance to avoid cracking of the casting. Too fast heating rate will cause a large temperature difference between the inside and outside of the casting, generating thermal stress, which may cause the casting to crack. Especially for castings with complex shape and uneven wall thickness, the control of the heating rate is more important. Generally, the heating rate is controlled at 100-150 degrees Celsius per hour, and when the temperature approaches the annealing temperature, the heating rate should be further reduced to 50-80 degrees Celsius per hour.

[0060] Exemplarily, the cooling process after annealing has a decisive influence on the final microstructure performance. The cooling methods include furnace cooling, air cooling, water cooling and other methods, and different cooling methods will obtain different microstructure. For the alloy stainless steel, the best microstructure performance can be obtained by adopting the method of furnace cooling to 600 degrees Celsius and then air cooling. The cooling speed in the furnace cooling stage is slow, which is beneficial to the analysis and dissolution of niobium carbide and niobium nitride, while avoiding the formation of martensite structure. The cooling speed in the air cooling stage is moderate, which can obtain fine and uniform ferrite-austenite dual-phase structure.

[0061] In one possible implementation, the annealing treatment can also improve the surface quality of the casting. The oxide skin and sand sticking formed during casting will be loose during annealing, facilitating subsequent cleaning work. At the same time, the annealing treatment can eliminate the residual stress on the surface of the casting, avoiding deformation in the subsequent machining process. The surface of the casting after annealing should be uniform gray, without obvious oxidation color and crack defects.

[0062] It should be noted that the improvement effect of annealing treatment on the internal microstructure of the casting can be verified by metallographic examination. The as-cast microstructure before annealing usually has defects such as dendritic segregation, columnar crystal and coarse precipitates, which will seriously affect the mechanical properties and corrosion resistance of the casting. After proper annealing treatment, the dendritic segregation is homogenized, the columnar crystal is transformed into equiaxed crystal, and the precipitates become fine and dispersed. The improvement of this microstructure can significantly improve the comprehensive performance of the casting, meeting the use requirements of the beer barrel pressure divider.

[0063] In one embodiment, the atmosphere control of the annealing treatment plays an important role in preventing oxidation of the casting. During high-temperature annealing, the surface of the casting is prone to oxidation, forming an oxide skin and affecting the surface quality. By introducing protective gas such as nitrogen or argon into the annealing furnace, the oxidation reaction can be effectively prevented. The purity of the protective gas should be not less than 99.9%, and the flow rate is determined according to the furnace volume, generally calculated as 2-3 cubic meters of protective gas per cubic meter of furnace volume per hour.

[0064] Specifically, the casting after annealing needs to be subjected to quality inspection to ensure that various performance indicators meet the requirements. The inspection items include dimensional accuracy, surface quality, chemical composition, mechanical properties and microstructure, etc. The dimensional accuracy inspection is carried out by using a three-coordinate measuring machine to ensure that the tolerance of the key dimensions is controlled within the design requirements. The surface quality inspection adopts the method of visual inspection and penetration detection to ensure that the surface is free of cracks, pores, inclusions and other defects. The chemical composition inspection is carried out by using a spectrum analyzer to ensure that the content of each element meets the design requirements, especially the molar ratio of niobium to carbon should be greater than 8.

[0065] Exemplarily, the mechanical property inspection includes tensile test, impact test and hardness test. The tensile test is used to determine the tensile strength, yield strength and elongation of the castings, which reflect the load-carrying capacity and plastic deformation capacity of the castings. The impact test is used to determine the impact toughness of the castings, which reflects the anti-fracture capacity of the castings under dynamic load. The hardness test is used to evaluate the wear resistance of the castings, which is of great significance for parts such as beer barrel pressure reducer that need to withstand certain wear.

[0066] In a possible implementation, the metallographic structure inspection is an important means to evaluate the effect of annealing treatment. By preparing a metallographic sample and observing under a microscope, the structural features of the castings can be intuitively understood. The ideal structure should be a fine and uniform ferrite-austenite dual-phase structure, in which the ferrite phase is continuously distributed and the austenite phase is island-shaped distributed. The niobium carbide and niobium nitride precipitates are finely and dispersedly distributed in the matrix, and there is no coarse precipitate and harmful phase. The grain size grade should reach more than 6 grade, to ensure that the castings have good comprehensive performance.

[0067] In summary, the Nb / C molar ratio in the alloy stainless steel of the present application is > 8 (to ensure that carbon is completely fixed and avoid the precipitation of chromium carbide), the use of the above high-strength stainless steel improves the corrosion resistance and service life, and the precision casting process ensures the size accuracy and appearance quality of the parts. The finished beer barrel pressure reducer has good air tightness, ensuring the stable and reliable operation of the pressure reducer, and has significant practical value and market prospect. Moreover, the Nb (niobium element) added in the above-mentioned base casting can effectively refine the grain structure, improve the corrosion resistance, fatigue strength and mechanical stability of the material, thereby enhancing the air tightness and prolonging the service life. At the same time, the material is processed by combining with the lost wax casting technology. In addition, the reasonable addition of Nb (niobium element) optimizes the solidification process of the castings, reduces casting defects, ensures the smooth surface and accurate size of the parts, and thus improves the overall performance of the product. The reasonable addition of Nb (niobium element) enhances the air tightness, so that the beer barrel pressure reducer remains stable in a high-pressure environment.

[0068] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essential content of the present application. The embodiments of the present application and the features in the embodiments can be arbitrarily combined without conflict.

Claims

1. An alloyed stainless steel, characterized in that According to the mass percentage, the following chemical components are included: C is 0.05-0.08, Si is 0.3-2.00, Mn is 0.55-1.50, P is 0.020-0.045, S is 0.010-0.020, Cr is 17.0-19.0, Ni is 0.30-0.70, Nb is 0.30-0.60, N is 0.020-0.050, and the balance is Fe.

2. Use of an alloyed stainless steel according to claim 1 in the casting of beer keg pressure reducers, characterized in that, It includes: An alloy stainless steel material is obtained, which includes, according to the mass percentage, C is 0.05-0.08, Si is 0.3-2.00, Mn is 0.55-1.50, P is 0.020-0.045, S is 0.010-0.020, Cr is 17.0-19.0, Ni is 0.30-0.70, Nb is 0.30-0.60, N is 0.020-0.050, and the balance is Fe; According to the alloy stainless steel, it is determined that the molar ratio of Nb to C is greater than 8, and carbon and nitrogen elements are fixed by forming niobium carbide and niobium nitride; The alloy stainless steel is used to prepare a beer barrel pressure divider, and the alloy stainless steel is processed by a precision casting method to form the beer barrel pressure divider; The alloy stainless steel is processed by the precision casting method to obtain a poured mold shell and perform annealing treatment.

3. The method of claim 2, wherein the composition is applied to the skin of the subject at least once a day. The alloy stainless steel material includes: By adjusting the C content in the alloy stainless steel to be less than 0.03 and the Si content to be less than 1.00, an optimized alloy stainless steel is obtained; According to the optimized alloy stainless steel, it is determined that the Mn content is less than 1.00 and the P content is less than 0.040, and a further optimized alloy stainless steel is obtained; By the further optimized alloy stainless steel, the S content is set to be less than 0.015 and the Cr content is 18, the Ni content is set to be less than 0.50 and the Nb content is 0.40; According to the further optimized alloy stainless steel, the N content is adjusted to be less than 0.030 and the balance is Fe, to obtain a final alloy stainless steel material; By the final alloy stainless steel material, it is verified that the molar ratio of Nb to C is greater than 8, and the carbon element is fixed to prevent the precipitation of chromium carbide and optimize the solidification process.

4. The method of claim 2, wherein the composition is applied to the skin of the user. The molar ratio of Nb to C is greater than 8, including: By the molar ratio of Nb to C being greater than 8, the niobium carbide formation condition is obtained, and the niobium nitride generation path is determined; According to the niobium carbide formation condition, the carbon element is fixed, and the nitrogen element fixation result is obtained; By the nitrogen element fixation result, the grain structure is refined, and the corrosion resistance is improved; According to the corrosion resistance improvement, the high temperature strength is optimized, and the creep resistance performance data is obtained; By the creep resistance performance data, the toughness and welding performance are improved, and the stability of the alloy stainless steel in casting is determined.

5. The method of claim 2, wherein the composition is applied to the skin of the user. The alloy stainless steel is used to prepare a beer barrel pressure divider, including: A wax mold is prepared from the alloy stainless steel to obtain a wax mold structure; According to the wax mold structure, a ceramic shell is made, and the ceramic shell firing parameters are determined; By the ceramic shell firing parameters, smelting and pouring are performed to obtain a pouring mold shell; According to the pouring mold shell, cutting and cleaning are performed, and the heat treatment conditions are determined; The surface is treated by the heat treatment condition, and a machining object is obtained; According to the machining object, detection and packaging are performed to determine the air tightness of the beer keg pressure reducer.

6. The method of claim 2, wherein the composition is applied to the skin of the human or animal. The precision casting method comprises: The sintering temperature range during the production of the ceramic shell is set by the precision casting method, and a sintering time setting is obtained; The sintering time setting is used to enhance the strength of the ceramic shell, and a casting defect reduction path is determined; The smelting temperature is optimized by the casting defect reduction path, and a refining and standing time is obtained; According to the refining and standing time, the pouring temperature is adjusted, and the interval time from the removal of the mold shell to pouring is determined; The high-temperature state of the mold shell is maintained by the interval time control, and a cold separation defect reduction result is obtained; According to the cold separation defect reduction result, post-pouring annealing treatment is verified, and the grain refinement effect is determined.

7. The method of claim 2, wherein the composition is applied to the skin of the human or animal. The smelting and pouring comprises: The refining temperature range is set by the smelting and pouring, and the refining and standing time interval is obtained; According to the refining and standing time interval, the pouring temperature range is determined, and the mold shell removal interval control is obtained; If the interval is less than the preset threshold value, high-temperature pouring is performed by the mold shell removal interval control, and defect minimization is determined; According to the defect minimization, the post-pouring mold shell is obtained, and the annealing holding temperature is determined; The furnace cooling process is performed by the annealing holding temperature, and the air cooling result is obtained; According to the air cooling result, the microstructure improvement is verified, and the precipitated phase reduction is determined.

8. The use according to claim 2, wherein The post-pouring mold shell is obtained and annealing treatment is performed, comprising: The annealing initial temperature is determined by the post-pouring mold shell, and the holding time setting is obtained; According to the holding time setting, furnace cooling to a specified temperature is performed, and the out-of-furnace air cooling path is determined; The grain is refined by the out-of-furnace air cooling path, and the columnar grain control is obtained; According to the columnar grain control, the point-like precipitated phase is reduced, and the ferrite matrix optimization is determined; The grain grade is verified by the ferrite matrix optimization, and the coarse grain suppression result is obtained; According to the coarse grain suppression result, the quality of the beer keg pressure reducer is improved, and the Nb oxidation problem is solved.

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