CN120575055A

CN120575055A - A high temperature resistant aluminum alloy ingot and preparation method thereof

Info

Publication number: CN120575055A
Application number: CN202510588909.1A
Authority: CN
Inventors: 黄海峰; 邵锦豪; 王俊盛
Original assignee: Sihui Runde Aluminum Co ltd
Current assignee: Sihui Runde Aluminum Co ltd
Priority date: 2025-05-08
Filing date: 2025-05-08
Publication date: 2025-09-02

Abstract

The invention relates to the technical field of aluminum alloy ingot preparation, and discloses a high-temperature-resistant aluminum alloy ingot and a preparation method thereof. The method comprises the steps of firstly setting chemical components in a high-temperature-resistant aluminum alloy ingot according to weight percentage to obtain a preparation raw material, then placing the preparation raw material into a smelting furnace, optimizing stirring speed and heating speed of the smelting furnace by using an improved differential evolution algorithm to enable the preparation raw material to be completely melted to obtain a preparation melt, adding a refining agent into the preparation melt, standing, removing scum after gathering to obtain a refined melt, controlling casting temperature by using a thermocouple multipoint calibration method, pouring the refined melt into a preheated mold, and cooling and solidifying to obtain the high-temperature-resistant aluminum alloy ingot. According to the invention, the high-temperature-resistant aluminum alloy ingot is obtained through batching, smelting, refining and casting, so that the purpose of preparing the high-temperature-resistant aluminum alloy ingot is realized, and the method is objective and accurate.

Description

High-temperature-resistant aluminum alloy ingot and preparation method thereof

Technical Field

The invention relates to the technical field of aluminum alloy ingot preparation, in particular to a high-temperature-resistant aluminum alloy ingot and a preparation method thereof.

Background

With the rapid development of the fields of national science and technology aerospace, automobile industry and the like, the demand for aluminum alloy materials with excellent mechanical properties, oxidation resistance and corrosion resistance at high temperature is increasingly urgent, and novel aluminum alloy materials are used for replacing copper which is originally used, so that the production cost is reduced, the market demand and scale expansion of the product with light weight are achieved, however, the traditional aluminum alloy is easy to soften, oxidize and corrode in a high-temperature environment, and the use requirement of the fields is difficult to meet.

Firstly, selecting ingredients, generally Si, cu, mg, ni, sr and the like, then adding the pure aluminum ingot, the pure copper plate, the aluminum-silicon intermediate alloy and the like which are weighed by smelting into a smelting furnace, setting smelting temperature, fully stirring for a period of time to obtain a melt, adding a covering agent at a heat preservation temperature, introducing Ar gas for continuous refining, and then standing to obtain an aluminum alloy melt;

The traditional aluminum alloy ingot preparation method has the problems that when ingredients are selected, the addition amount of part of alloy elements is too high, the uneven alloy components, the processing performance and the like are possibly caused, meanwhile, the heat treatment process during smelting is complex, the generation cost is high, and finally, the obtained aluminum alloy ingot finished product has poor temperature resistance and not particularly good creep resistance.

Disclosure of Invention

Aiming at the problems in the related art, the invention provides a high-temperature-resistant aluminum alloy ingot and a preparation method thereof, so as to overcome the technical problems in the prior related art.

In order to solve the technical problems, the invention is realized by the following technical scheme:

The invention relates to a preparation method of a high-temperature-resistant aluminum alloy ingot, which comprises the following steps:

S1, smelting, namely after pretreatment of preparation raw materials, putting an aluminum ingot into a smelting furnace, heating to 750-830 ℃, sequentially adding the preparation raw materials, and optimizing the stirring speed and the heating speed of the smelting furnace by using an improved differential evolution algorithm to obtain an optimized stirring speed and an optimized heating speed of the smelting furnace, so that the preparation raw materials are completely melted, and a preparation melt is obtained;

S2, refining, namely adding a refining agent into the prepared melt, standing, and removing after scum is gathered to obtain refined melt;

and S3, casting, namely controlling the casting temperature to be 700-720 ℃ by using a thermocouple multipoint calibration method, pouring the refined melt into a preheated mold, and cooling and solidifying to obtain the high-temperature-resistant aluminum alloy ingot.

Preferably, the step S1 includes the steps of:

S11, according to weight percentage, each chemical composition in the high temperature resistant aluminum alloy ingot is composed of 0.05-0.1% of Ti, 2.1-2.3% of Ni, 2.1-2.3% of Mn, 0.7% of Cu, 0.03% of Mg, 0.2% of Zn, 0.7% of Si, 0.7% of Fe, less than or equal to 0.15% of impurity element, and the balance of Al, and the aluminum ingot and the intermediate alloy are weighed to obtain preparation raw materials, wherein the intermediate alloy comprises Al-Si intermediate alloy, al-Cu intermediate alloy, al-Mn intermediate alloy, al-Ti intermediate alloy and Al-Ni intermediate alloy;

Carrying out sand blasting treatment on the surface of an aluminum ingot, crushing the intermediate alloy into blocks of 50-80mm to obtain intermediate alloy fragments, and baking the intermediate alloy fragments in a 250 ℃ environment for 2 hours to obtain a preparation raw material;

Placing an aluminum ingot into a smelting furnace and paving the aluminum ingot on the bottom layer of the smelting furnace, placing an Al-Mn intermediate alloy and an Al-Si intermediate alloy on the middle layer of the smelting furnace, placing an Al-Ti intermediate alloy on the upper layer of the smelting furnace, and placing the rest of other preparation raw materials on the top layer of the smelting furnace and covering the rest of aluminum ingot, wherein the heating speed is less than or equal to 100 ℃ before the aluminum ingot is arranged in the smelting furnace at 400 ℃ and is less than or equal to 50 ℃ when the aluminum ingot is arranged in the smelting furnace at 400 ℃ to 750 ℃;

s12, continuously and fully stirring by using electromagnetic stirring in the smelting process, introducing a scale mechanism into a differential evolution algorithm to obtain an improved differential evolution algorithm, optimizing the stirring speed and the heating speed of the smelting furnace by using the improved differential evolution algorithm to obtain an optimized stirring speed and an optimized heating speed of the smelting furnace, and specifically comprising the following steps of:

S121, measuring the uniformity, the number and the average size of inclusions in the melting process of the raw materials in the smelting furnace in real time, taking the product of the number of the inclusions and the average size of the inclusions as an inclusion index, and establishing an objective function based on the maximum high temperature resistance, wherein the formula is as follows:

;

Wherein F represents an objective function, AndThe weight coefficient is represented by a number of weight coefficients,The index of the inclusion is indicated,Indicating uniformity;

In the melting process of the raw materials prepared in the smelting furnace, the temperature rising speed before 400 ℃ in the smelting furnace is recorded as a first temperature rising speed, the temperature rising speed in the smelting furnace at 400-750 ℃ is recorded as a second temperature rising speed, and the stirring speed, the first temperature rising speed and the second temperature rising speed are combined to form a parameter combination;

S122, taking the objective function as a fitness function, searching the best fitness function value, namely searching the best parameter combination, taking the searching process as a searching space, setting the number of vector populations as p and the dimension of the vector populations as q in the searching space, initializing the vector populations, randomly selecting three vectors in the vector populations, namely a first target vector, a second target vector and a third target vector, and setting the current iteration time as t and the ith vector in the vector populations at the time of the t iteration Wherein the scaling factorRepresenting a random number between intervals 0,1, 、 AndRespectively representing a first target vector, a second target vector and a third target vector, and combining the vectorsMarking as a target vector;

S123, performing cross operation on vector populations, and setting a cross probability factor as , Representing random numbers between intervals 0,1, whenWhen the target vector is regarded as a variance vector, whenRandomly selecting vectors from a vector population to be regarded as variant vectors to generate new vectors, introducing a scale mechanism to replace selection operation, calculating Euclidean distances of other vectors in the target vector and the vector population to obtain Euclidean distance sets, sorting the Euclidean distance sets according to ascending order, normalizing to generate ranking indexes, adding the ranking indexes into a scale set when the fitness function value of the corresponding vector of the ranking indexes is smaller than that of the target vector, calculating the difference value of the fitness function value of the corresponding vector of the ranking indexes and the fitness function value of the target vector, recording the difference value as a fitness difference value to form a fitness difference value set, calculating the weighted average value of products of the fitness difference value set and the scale set, and calculating the evolution scale indexWherein c represents a constant of 0.1,Representing a weighted average;

S124, setting a scale threshold, when the evolution scale index is smaller than or equal to the scale threshold, regarding a new vector as an ith vector in the vector population at the time of the t+1st iteration, otherwise regarding a vector corresponding to the current optimal fitness function value as the ith vector in the vector population at the time of the t+1st iteration, completing the current iteration, generating a next generation vector population, continuing iteration, setting the maximum iteration times, stopping iteration when the current iteration times reach the maximum iteration times, generating a final vector population, selecting a vector corresponding to the optimal fitness function value, and obtaining the optimized stirring speed and the optimized smelting furnace heating speed;

S13, smelting according to the optimized stirring speed and the optimized heating speed of the smelting furnace, introducing Ar with the flow of 8-10L/min and the purity of 99.99% in the process of fully stirring, at the moment, raising the temperature in the smelting furnace to 750+/-10 ℃, preserving heat for 30 minutes, raising the temperature in the smelting furnace to 800+/-5 ℃, preserving heat for 45 minutes, raising the temperature in the smelting furnace to 830+/-3 ℃, preserving heat for 15 minutes, and completely melting the preparation raw materials in the smelting furnace to form the preparation melt.

Preferably, the step S2 includes the steps of:

S21, after a prepared melt is formed, the temperature in a smelting furnace is reduced to 730 ℃, a refining agent is added, standing treatment is carried out, the temperature in the smelting furnace is maintained at 730 ℃ for 25 minutes, primary standing is completed, the temperature in the smelting furnace is reduced to 720 ℃ and maintained for 15 minutes, secondary standing is completed, and surface scum is obtained;

S22, selecting a titanium alloy scraping plate, preheating to 300 ℃, and removing surface scum to obtain refined melt.

Preferably, the step S3 includes the steps of:

s31, controlling the casting temperature to 700-720 ℃ by using a thermocouple multipoint calibration method, wherein the method comprises the following specific steps:

S311, selecting a plurality of thermocouples and standard thermocouples to be placed in the same incubator, adjusting the temperature, recording the readings of the plurality of thermocouples and the standard thermocouples at different temperatures, and obtaining standard thermocouple data and a plurality of thermocouple data;

S312, placing a plurality of new thermocouples at the bottom layer, the middle layer and the upper layer of the smelting furnace, numbering, recording the readings of the plurality of new thermocouples, calculating the average value of the readings of the plurality of new thermocouples to obtain casting temperature, and keeping the casting temperature at 710+/-10 ℃;

S32, selecting a casting mold, heating the casting mold to 250-300 ℃ to obtain a preheated mold, pouring refined melt into the preheated mold, controlling the pouring speed, setting the pouring speed to be 5-8kg/S in the previous u-second time period, and setting the pouring speed to be 3-5kg/S in the u-second time period;

S33, in the casting process, a water cooling system with the cooling water flow rate of 2.5m3/h and the water temperature of 25+/-1 ℃ is used for cooling, the cooling temperature is controlled to be 50 ℃ per minute within the casting temperature of 700 ℃ to 550 ℃, the cooling temperature is controlled to be 20 ℃ per minute within the casting temperature of 550 ℃ to 400 ℃, the cooling temperature is controlled to be 10 ℃ per minute within the casting temperature of 400 ℃ to 200 ℃, and the high-temperature-resistant aluminum alloy ingot is obtained after cooling solidification.

The invention has the following beneficial effects:

1. According to the invention, the removal rate of the surface oxide layer is greatly increased through aluminum ingot sand blasting, the slag inclusion risk in the subsequent smelting is reduced, the total amount of ultralow impurities is controlled, the generation of a grain boundary brittle phase (such as Fe-Si phase) is reduced, high-temperature brittleness is avoided, and the creep resistance of the aluminum alloy ingot at high temperature is improved.

2. According to the method, gradient smelting is introduced, an improved differential evolution algorithm is used for optimizing the stirring speed and the heating speed of the smelting furnace, a scale mechanism is used for effectively quantifying the evolution scale of the current vector, global searching capacity and local optimal solution jumping-out capacity are greatly improved, parameters are few, robustness is good, high efficiency and universality are shown in the complex optimization problem, the inclusion content of a high-temperature-resistant aluminum alloy ingot is remarkably reduced, high-temperature performance is improved, meanwhile, the melting rate of intermediate alloy is greatly increased by combining a three-stage temperature control method, grain size is refined, and component uniformity is improved.

3. The method improves slag phase aggregation efficiency by using two-stage standing, increases melt cleanliness after slag skimming, and ensures that a multipoint thermocouple provides accurate temperature data in the directional solidification casting process by using a thermocouple multipoint calibration method, thereby optimizing process parameters and improving structural uniformity and mechanical properties of the aluminum alloy ingot.

4. The invention effectively inhibits the generation of coarse phases (such as Al ₃ Ni) by controlling the pouring speed and the cooling flow, simultaneously controls the casting porosity, obviously improves the yield, reduces the generation cost, forms closed-loop control by a process system, and realizes the simplification of the heat treatment process and the improvement of the processing performance of the high-temperature-resistant aluminum alloy.

Of course, it is not necessary for any one product to practice the invention to achieve all of the advantages set forth above at the same time.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the invention, the drawings that are needed for the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the invention, and that it is also possible for a person skilled in the art to obtain the drawings from these drawings without inventive effort.

Fig. 1 is a schematic flow chart of a method for preparing a high-temperature-resistant aluminum alloy ingot.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments that can be obtained by a person of ordinary skill in the art without making any inventive effort are within the scope of the present invention.

Example 1

Further, in order to better introduce the technical scheme of the embodiment of the invention, as shown in fig. 1, the embodiment of the invention provides a high-temperature resistant aluminum alloy ingot and a preparation method thereof, and the method specifically comprises the following steps:

S1, smelting, namely putting an aluminum ingot into a smelting furnace, heating to 750-830 ℃, sequentially adding preparation raw materials, and optimizing the stirring speed and the heating speed of the smelting furnace by using an improved differential evolution algorithm to obtain an optimized stirring speed and an optimized heating speed of the smelting furnace, so that the preparation raw materials are completely melted, and a preparation melt is obtained;

the step S1 comprises the following steps:

;

S13, smelting according to the optimized stirring speed and the optimized heating speed of the smelting furnace, introducing Ar with the flow of 8-10L/min and the purity of 99.99% in the process of fully stirring, wherein the temperature in the smelting furnace is increased to 750+/-10 ℃, the temperature is kept for 30 minutes, the temperature in the smelting furnace is increased to 800+/-5 ℃, the temperature is kept for 45 minutes, the temperature in the smelting furnace is increased to 830+/-3 ℃ and the temperature is kept for 15 minutes, and the preparation raw materials in the smelting furnace are completely melted to form a preparation melt;

In the embodiment, the removal rate of the surface oxide layer is greatly increased by the sand blasting treatment of the aluminum ingot, the slag inclusion risk in the subsequent smelting is reduced, simultaneously, the total amount of ultra-low impurities is controlled, the generation of a crystal boundary brittle phase (such as Fe-Si phase) is reduced, high-temperature brittleness is avoided, the creep resistance of the aluminum alloy ingot at high temperature is improved, 1000kg of preparation raw materials are selected, 2.5kg of Al-Si master alloy, 10.5kg of Al-Cu master alloy, 2.2kg of Al-Mn master alloy, 1.5kg of Al-Ti master alloy and 2.2kg of Al-Ni master alloy, 981.1kg (including the total amount of impurities) of the Al (allowance) is controlled, the master alloy is crushed into 60mm blocks, and the blocks are placed in a 250 ℃ oven for baking for 2 hours, so that the surface moisture and volatile impurities are removed, and the dried preparation raw materials are obtained;

Introducing gradient smelting, optimizing the stirring speed and the heating speed of a smelting furnace by using an improved differential evolution algorithm, wherein the algorithm uses a scale mechanism to effectively quantify the evolution scale of a current vector, greatly increases global searching capacity and jumping-out local optimal solution capacity, has few parameters and good robustness, shows high efficiency and universality in complex optimization problems, remarkably reduces the inclusion content of a high-temperature-resistant aluminum alloy ingot and improves high-temperature performance, simultaneously greatly increases the melting rate of an intermediate alloy by combining a three-section temperature control method, refines grain size, improves component uniformity, remarkably improves the quality and process efficiency of an aluminum alloy melt by adopting the synergistic effect of gradient smelting, algorithm optimization and dynamic temperature control, is suitable for industrial production of the high-temperature-resistant alloy, and is particularly suitable for iteration, for example, a first heating section is set to be 100 ℃ in initial heating speed, a second heating section is set to be 50 ℃ in initial heating speed, the stirring speed is set to be 200r/min, the number of 15/mm 2 is obtained by measurement, the average population size is 0.1mm, the average population size is set to be 3mm, the maximum number of the two-dimensional values is set to be equal to 5 ℃ and the maximum value of the maximum current vector is set to be 0.45 ℃ in a random variation speed, and the maximum value is set to be equal to 0.45 ℃ in iteration speed, and the maximum ratio is set to be equal to 0.15 m, the maximum value is equal to 0.45 m, and the maximum value is equal to the maximum value of the iteration coefficient is calculated to the maximum value of the current vector is calculated, and the maximum value is calculated to be the maximum value of the current vector, and the current vector is the maximum value between the temperature and the temperature-phase is calculated is equal to the maximum value, the number of the inclusions is 12 per mm <2 >, the average size is 0.05mm, the uniformity is 85%, the front-back heating speed is optimized, the aluminum ingot can be prevented from being rapidly expanded and cracked, the intermediate alloy is ensured to be fully diffused, unmelted particles are reduced, the uniformity and the high temperature resistance are improved, the fixed stirring speed is optimized, and impurities in the prepared melt are reduced;

the step S2 comprises the following steps:

s22, selecting a titanium alloy scraping plate, preheating to 300 ℃, and removing surface scum to obtain refined melt;

In the embodiment, the slag phase gathering efficiency is improved by using two-stage standing, the cleanliness of a melt after slag skimming is improved, specifically, for example, the primary standing is that the temperature of 730 ℃ is kept constant for 25 minutes, a refining agent reacts with the melt to generate AlF ₃ gas to drive oxide inclusion to float upwards, the secondary standing is that the furnace temperature is regulated to 720 ℃, the heat preservation is continued for 15 minutes, smaller scum is further gathered to form a continuous slag layer, a titanium alloy scraping plate is selected, the titanium alloy scraping plate is heated to 300 ℃ in a special preheating furnace and is kept for 10 minutes (the phenomenon that a cold tool contacts the melt to cause local solidification) before the use, the preheating scraping plate is slowly inserted into the surface of the melt at an inclined angle of 45 ℃, the furnace wall is pushed clockwise, off-white scum is continuously removed, the two-stage standing improves the slag phase gathering efficiency, and the cleanliness of the melt after slag skimming is improved;

s3, casting, namely controlling the casting temperature to be 700-720 ℃ by using a thermocouple multipoint calibration method, pouring the refined melt into a preheated die, and cooling and solidifying to obtain a high-temperature-resistant aluminum alloy ingot;

the step S3 comprises the following steps:

S33, in the casting process, a water cooling system with the cooling water flow rate of 2.5m3/h and the water temperature of 25+/-1 ℃ is used for cooling, the cooling temperature is controlled to be 50 ℃ per minute within the casting temperature of 700-550 ℃, the cooling temperature is controlled to be 20 ℃ per minute within the casting temperature of 550-400 ℃, the cooling temperature is controlled to be 10 ℃ per minute within the casting temperature of 400-200 ℃, and the high-temperature-resistant aluminum alloy ingot is obtained after cooling solidification;

In the embodiment, a thermocouple multipoint calibration method is used for ensuring that a multipoint thermocouple provides accurate temperature data in the directional solidification casting process, so that the process parameters are optimized, and the structural uniformity and mechanical properties of the aluminum alloy ingot are improved; the method comprises the steps of controlling casting speed and cooling flow, effectively inhibiting generation of coarse phases, controlling casting porosity, obviously improving ingot yield, reducing production cost, forming closed loop control by a process system, simplifying a heat treatment process and improving processing performance of high-temperature resistant aluminum alloy, specifically, for example, selecting 5K-type thermocouples and standard S-type thermocouples to perform calibration test within a range of 600-750 ℃, setting a threshold value to be +/-5 ℃, replacing thermocouples with a deviation of 8 ℃, adopting 4 thermocouples which are qualified in calibration, arranging the thermocouples at the bottom layer, the middle layer and the upper layer of a smelting furnace, recording readings 715 ℃, 708 ℃, 712 and 710 ℃, calculating average temperature 711 ℃, preheating a die to 280 ℃, adopting a casting speed of 6.5kg/S (u=30 is acquired in the first u seconds), adjusting to be 4.2kg/S in the subsequent stage, controlling cooling water Wen Duwen in the whole process to be within a range of 24.5-25.8 ℃, obtaining sample aluminum alloy ingots after cooling, calculating the surface components of the sample aluminum alloy ingots by using X-ray, recording the surface components of the sample aluminum alloy to be less than 1 percent of standard, analyzing the sample aluminum alloy ingots, and obtaining the sample aluminum alloy ingots with a low-grade alloy temperature of 1 percent of standard, if the surface components are not qualified, and the sample aluminum alloy is not subjected to the sample is subjected to the standard analysis, and the sample has a low-grade temperature is less than 1 percent of standard, and the sample is not qualified, and the sample is obtained, calculating the ratio of the number of qualified finished products to the number of sample aluminum alloy ingots to obtain the yield of 92%;

Example 2

On the basis of the embodiment 1, the temperature rising speed of the fixed smelting furnace is optimized, and the stirring speed is different from the embodiment 1, specifically, the first temperature rising section is set to be 100 ℃ per hour, the second temperature rising section is set to be 50 ℃ per hour, the stirring speed is initially set to be 200r/min, the number of inclusions is measured to be 15 per mm & lt 2 & gt, the average size is 0.1mm, the uniformity is 85%, the population quantity p=50 is set, the dimension q=1 (stirring speed) is 0.8, the maximum iteration number is 100, the objective function weight is 0.7 and 0.3 respectively, a variation vector is generated by randomly selecting three parameter combinations, the characteristic of the variation vector is reserved according to the probability of 0.8, the ranking index of the Euclidean distance is calculated, the new vector is reserved when the ranking index of the evolutionary distance is smaller than 0.15, the stirring speed is 320r/min when the maximum iteration number is calculated, the number of inclusions is measured to be 25 per mm & lt 2 & gt, the average size is 0.1mm, the uniformity is 86%, the maximum temperature is kept at the fixed smelting furnace, the temperature rising speed is maintained, the local uniformity is kept to be 0.7, the aluminum alloy sample segregation coefficient is calculated to be higher than the 0.1%, and the sample segregation rate is calculated to be higher than the 0.1.1 percent, and the sample segregation rate of the high temperature of the alloy is calculated.

Example 3

On the basis of the embodiment 1, the temperature rising speed of the smelting furnace is optimized by fixing the stirring speed, which is different from the embodiment 1; the method comprises the steps of setting an initial heating speed to be 100 ℃ per hour, setting an initial heating speed to be 50 ℃ per hour, setting a fixed stirring speed to be 200r per minute, measuring 15 inclusions per mm < 2 >, an average size of 0.1mm, setting uniformity to be 85%, setting population quantity p=50, setting dimension q=2 (2 heating speeds), setting crossover probability to be 0.8, setting maximum iteration times to be 100, setting objective function weights to be 0.7 and 0.3 respectively, randomly selecting three parameter combinations to generate a variation vector, reserving variation vector characteristics according to the probability of 0.8, calculating Euclidean distance ranking index, reserving a new vector when an evolution scale index is smaller than 0.15, obtaining the first heating speed to be 98 ℃ per hour, measuring the second heating speed to be 48 ℃ per hour, measuring 13 inclusions per mm < 2 >, setting average size to be 0.05mm, setting uniformity to be 82%, optimizing front and back heating speeds, avoiding rapid expansion cracking of aluminum ingots, guaranteeing full diffusion of intermediate alloy, reducing the diffusion of the alloy, and obtaining high-temperature alloy sample phase alloy particles with the sample temperature drop coefficient of being 1.88%, and obtaining the high-temperature alloy sample phase alloy with the sample segregation coefficient of being calculated to be 1.88%.

Example 4

On the basis of the embodiment 1, the method is different from the embodiment 1 in that the stirring speed and the heating speed of a smelting furnace are fixed, specifically, the first heating section is set to be 100 ℃ per hour, the second heating section is set to be 50 ℃ per hour, the fixed stirring speed is 200r/min, the number of inclusions is measured to be 15 per mm < 2 >, the average size is 0.1mm, the uniformity is 85%, the sample aluminum alloy ingot is obtained through refining and casting, the local segregation is caused in the smelting process due to the heating speed of the fixed smelting furnace, the stirring speed is fixed, the raw materials cannot be completely melted, the component segregation degree of the sample aluminum alloy ingot is measured to be 3.5%, the yield is calculated to be 82%, and compared with the embodiment 1, the high temperature resistance is reduced.

Example 5

On the basis of example 1, different from example 1, the stirring speed and the heating speed of the smelting furnace are optimized, but 4 thermocouples which are not subjected to calibration test are adopted and are arranged at the bottom layer, the middle layer and the upper layer of the smelting furnace, the readings of 705 ℃, 710 ℃, 672 ℃ and 670 ℃ are recorded, the average temperature 689.25 ℃ is calculated, and is lower than the casting temperature by 710+/-10 ℃, so that accurate temperature data cannot be provided, the melt fluidity is poor due to insufficient temperature, the melt state is uneven, cold separation defects are formed, the structural uniformity and the mechanical property of an aluminum alloy ingot are greatly reduced, the sample aluminum alloy ingot is obtained, the component segregation degree of the sample aluminum alloy ingot is measured to be 3.0%, and the yield is calculated to be 75% lower than the high temperature resistance of example 1.

Example 6

On the basis of the embodiment 1, the stirring speed and the heating speed of a smelting furnace are optimized, a thermocouple multipoint calibration method is used for controlling the casting temperature, but the casting speed is adopted in the whole process, the high-speed impact causes the back pressure of a cavity to be increased rapidly, a large-area surface cold partition is formed, a honeycomb-shaped air hole group is generated, the density of detected air holes reaches 22/cm < 2 >, the density of the detected air holes is far higher than the rated air hole density, shrinkage cavities are generated during cooling solidification, the maximum aperture is measured to be 3.8mm, the safety standard is exceeded by 4.7 times, a sample aluminum alloy ingot is obtained, the component segregation degree of the sample aluminum alloy ingot is measured to be 2.8%, and the calculated yield is 70% and is lower than the high temperature resistance of the embodiment 1.

In the above embodiments 1-6, the method for detecting the composition segregation degree of the sample aluminum alloy ingot uses the X-ray fluorescence spectrum to perform composition analysis on the surface of the sample aluminum alloy ingot, then calculates the relative standard deviation, and measures to obtain the composition segregation degree, the method for detecting the yield of the sample aluminum alloy ingot uses the 600 ℃ electric furnace temperature resistance test, after 2 hours, the surface of the sample aluminum alloy ingot is marked as a qualified finished product, otherwise marked as a disqualified finished product, and the ratio of the number of qualified finished products to the number of sample aluminum alloy ingots is calculated to obtain the yield.

In the description of the present specification, the descriptions of the terms "one embodiment," "example," "specific example," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above disclosed preferred embodiments of the invention are merely intended to help illustrate the invention. The preferred embodiments are not exhaustive or to limit the invention to the precise form disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best understand and utilize the invention.

Claims

1. A high-temperature resistant aluminum alloy ingot, characterized in that the chemical composition of the high-temperature resistant aluminum alloy ingot is: Ti: 0.05-0.1%, Ni: 2.1-2.3%, Mn: 2.1-2.3%, Cu < 0.7%, Mg < 0.03%, Zn < 0.2%, Si < 0.7%, Fe < 0.7%, the total amount of impurity elements ≤ 0.15%, and the balance is Al.

2. The high-temperature resistant aluminum alloy ingot according to claim 1 is characterized in that the raw materials for preparing the high-temperature resistant aluminum alloy ingot include aluminum ingots and master alloys, and the master alloys include Al-Si master alloys, Al-Cu master alloys, Al-Mn master alloys, Al-Ti master alloys and Al-Ni master alloys.

3. A method for preparing a high-temperature resistant aluminum alloy ingot, characterized in that it comprises the following steps:

S1. Melting: After the raw materials are pretreated, the aluminum ingot is placed in a melting furnace and heated to 750-830°C. The raw materials are then added in sequence. The stirring speed and the melting furnace heating rate are optimized to obtain the optimized stirring speed and the optimized melting furnace heating rate so that the raw materials are completely melted to obtain a prepared melt.

S2, refining: adding a refining agent to the prepared melt, allowing it to stand and then scraping off the scum after it has accumulated to obtain a refined melt;

S3. Casting: The casting temperature is controlled at 700-720°C using a thermocouple multi-point calibration method. The refined melt is poured into a preheated mold and cooled and solidified to obtain a high-temperature resistant aluminum alloy ingot.

4. The method for preparing a high-temperature resistant aluminum alloy ingot according to claim 3, wherein the raw material pretreatment comprises the following steps:

The surface of the aluminum ingot is sandblasted, and the intermediate alloy is crushed into 50-80 mm blocks to obtain intermediate alloy fragments, which are then baked at 250° C. for 2 hours to obtain the preparation raw material.

5. The method for preparing a high temperature resistant aluminum alloy ingot according to claim 4, wherein said S1 comprises the following steps:

S11. Using gradient smelting, place the aluminum ingot into the melting furnace and lay it on the bottom layer of the melting furnace, place the Al-Mn master alloy and the Al-Si master alloy in the middle layer of the melting furnace, and then place the Al-Ti master alloy on the upper layer of the melting furnace. Place the remaining other prepared raw materials on the top layer of the melting furnace and cover the remaining aluminum ingot; set the heating rate before 400°C in the melting furnace to be less than or equal to 100°C, and the heating rate between 400°C and 750°C in the melting furnace to be less than or equal to 50°C;

S12. During the smelting process, electromagnetic stirring is used to continuously and fully stir the mixture. A scaling mechanism is introduced into the differential evolution algorithm to obtain an improved differential evolution algorithm. The improved differential evolution algorithm is used to optimize the stirring speed and the heating rate of the smelting furnace to obtain an optimized stirring speed and an optimized heating rate of the smelting furnace.

S13. Smelting is performed according to the optimized stirring speed and the optimized melting furnace heating rate. Ar with a flow rate of 8-10 L/min and a purity of 99.99% is introduced during the sufficient stirring process; at this time, the temperature in the melting furnace is raised to 750±10° C. and kept warm for 30 minutes, then the temperature in the melting furnace is raised to 800±5° C. and kept warm for 45 minutes, then the temperature in the melting furnace is raised to 830±3° C. and kept warm for 15 minutes, and the prepared raw materials in the melting furnace are completely melted to form a prepared melt.

6. The method for preparing a high temperature resistant aluminum alloy ingot according to claim 5, wherein said S12 comprises the following steps:

The S121 measures the uniformity, number, and average size of inclusions during the melting process of the raw materials prepared in the smelting furnace in real time. The product of the number of inclusions and the average size of inclusions is used as the inclusion index. The objective function is established based on the maximum high-temperature resistance. The formula is as follows:

;

Where F represents the objective function, and represents the weight coefficient, represents the inclusion index, Indicates uniformity;

During the melting process of the raw materials prepared in the smelting furnace, the heating rate before 400°C in the smelting furnace is recorded as the first heating rate, and the heating rate between 400°C and 750°C in the smelting furnace is recorded as the second heating rate. The stirring rate, the first heating rate, and the second heating rate are combined to form a parameter combination.

S222: Using the objective function as a fitness function, the process of searching for the optimal fitness function value is the process of searching for the optimal parameter combination. The search process is regarded as a search space, wherein a vector population exists in the search space, and vectors in the vector population represent parameter combinations. After initializing the vector population, the vector population is mutated. The current number of iterations is set to t, and the i-th vector in the vector population at the t-th iteration is calculated to obtain the target vector.

S223, performing a crossover operation on the vector population to generate a new vector; at this time, introducing a scale mechanism replacement selection operation, calculating the Euclidean distance between the target vector and other vectors in the vector population, obtaining a Euclidean distance set, sorting the Euclidean distance set in ascending order, and performing normalization processing to generate a ranking index; when the fitness function value of the vector corresponding to the ranking index is less than the fitness function value of the target vector, adding the ranking index to the scale set; calculating the difference between the fitness function value of the vector corresponding to the ranking index and the fitness function value of the target vector, recording it as the fitness difference, and forming a fitness difference set; calculating the weighted average of the product of the fitness difference set and the scale set, and then calculating the evolutionary scale index;

S224. Set a scale threshold. When the evolution scale index is less than or equal to the scale threshold, regard the new vector as the i-th vector in the vector population at the t+1th iteration; otherwise, regard the vector corresponding to the current best fitness function value as the i-th vector in the vector population at the t+1th iteration. Complete the current iteration, generate the next generation of vector population, and continue iterating. Set the maximum number of iterations. When the current number of iterations reaches the maximum number of iterations, stop the iteration, generate the final vector population, select the vector corresponding to the best fitness function value, and obtain the optimized stirring speed and the optimized heating rate of the smelting furnace.

7. The method for preparing a high temperature resistant aluminum alloy ingot according to claim 6, wherein said S2 comprises the following steps:

S21. After the prepared melt is formed, the temperature in the smelting furnace is lowered to 730° C., a refining agent is added, and the smelting furnace is allowed to stand for 25 minutes at 730° C. to complete the first standing period. The temperature in the smelting furnace is lowered to 720° C. to complete the second standing period for 15 minutes to obtain surface slag.

S22. Select a titanium alloy scraper, preheat it to 300°C, remove surface scum, and obtain a refined melt.

8. The method for preparing a high temperature resistant aluminum alloy ingot according to claim 7, wherein said S3 comprises the following steps:

S31, using thermocouple multi-point calibration method to control the casting temperature at 700-720℃;

S32. Select a casting mold, raise the temperature of the casting mold to 250° C.-300° C. to obtain a preheated mold, pour the refined melt into the preheated mold, and control the pouring speed to set the pouring speed in the first u second period to 5-8 kg/s and the pouring speed after the u second period to 3-5 kg/s;

S33. During the casting process, a water cooling system is used for cooling. When the casting temperature is within the range of 700°C-550°C, the cooling temperature is controlled at 50°C/min; when the casting temperature is within the range of 550°C-400°C, the cooling temperature is controlled at 20°C/min; when the casting temperature is within the range of 400°C-200°C, the cooling temperature is controlled at 10°C/min. After cooling and solidification, a high-temperature resistant aluminum alloy ingot is obtained.

9. The method for preparing a high-temperature resistant aluminum alloy ingot according to claim 8, characterized in that a water cooling system with a cooling water flow rate of 2.5 m³/h and a water temperature of 25±1°C is used for cooling.

10. The method for preparing a high temperature resistant aluminum alloy ingot according to claim 9, wherein said S31 comprises the following steps:

S311. Selecting a plurality of thermocouples and a standard thermocouple and placing them in the same constant temperature box, adjusting the temperature, recording the readings of the plurality of thermocouples and the standard thermocouple at different temperatures, and obtaining standard thermocouple data and a plurality of thermocouple data; comparing the difference between the standard thermocouple data and the plurality of thermocouple data, generating an error curve, setting a deviation threshold, and replacing the thermocouples corresponding to the difference greater than the deviation threshold in the error curve to obtain a plurality of new thermocouples;

S312. Place several new thermocouples on the bottom, middle and upper layers of the smelting furnace and number them. Record the readings of the several new thermocouples. Calculate the average value of the readings of the several new thermocouples to obtain the casting temperature. Maintain the casting temperature at 710±10°C.