A method of controlling inorganic sand cores

Abstract

This invention relates to a method for controlling the strength of inorganic sand cores. Specifically, it relates to the field of inorganic sand core technology. After the inorganic sand cores are produced, their strength gradually increases before returning to room temperature, reaching its highest value after 20 minutes. After 30 minutes, the strength gradually decreases. Therefore, the optimal time for transferring inorganic sand cores from the box to the core storage facility is 20-30 minutes. Storing them on-site for 0.5-1 hour, followed by 1-3 days in the core storage facility, can improve their strength. Sand cores stored for more than 2 hours will not show any further strength improvement or recovery after being placed in the core storage facility. Sand cores placed in the core storage facility should be used within 3 days to prevent damage. If inorganic sand cores are stored in the core storage facility for 4 days, their tensile strength will decrease to below 0.6 MPa. During storage or use, core breakage may occur, and the moisture content will significantly increase.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inorganic sand core preparation, and is a control method of inorganic sand core. BACKGROUND

[0002] In order to realize green manufacturing in the foundry industry, it is necessary to realize green materials from the source of casting. The casting source materials include raw materials and auxiliary materials. The casting raw materials such as pig iron, scrap steel, aluminum liquid, etc. form the main part of the casting. These materials will not pollute the environment in the smelting or refining process, except that the energy consumption is large. The casting auxiliary materials such as raw sand, resin binder and coating materials will not enter the main part of the casting, but are essential production materials in the production process of the casting. Although most of these essential molding materials are refractory materials and will not produce toxic and harmful gases in the high-temperature liquid pouring process, one of the resin materials, as a molding binder material, forms a sand mold, and a large amount of VOCs (volatile organic compounds) will be produced when the high-temperature liquid enters the sand mold, polluting the environment. Therefore, inorganic sand cores have gradually been favored by the foundry industry as the main material for green casting.

[0003] Patent document 1 (CN114535499A) discloses a kind of casting anti-hygroscopic type inorganic binder powder and activation liquid and use method, the inorganic binder powder includes sodium silicate powder 0.5-3.0%, sulfonate 0.01-1.0%, aluminosilicate 0.01-1.0%, microsilica 0.1-3.0%, borax 0.01-1.0%, sodium polymetaphosphate 0.01-1.0%, malt dextrin 0.1-2.0%, barium sulfate 0.1-2.0%, lithium hydroxide 0.1-2.0%, hydrophobic nano-silicon dioxide 0.1-2.0%. The activation liquid includes deionized water 1.0-5.0%, amino silane coupling agent 0.01-1.0%, organic acid 0.01-1.0%. And the corresponding use method includes the steps of preparing composition A, composition B, activation liquid, sand mixing, and inorganic sand core preparation. The inorganic binder powder and the activation liquid are convenient to store, transport and use, and can improve the strength and moisture resistance of the sand core.

[0004] Patent document 2 (CN110724861A) relates to a multifunctional sand core storage bin, comprising: a storage rack for storing sand cores, a crane for conveying sand cores to the storage rack or taking them out; wherein a plurality of vertical columns perpendicular to the ground are provided on the storage rack, a plurality of layers of cross beams are vertically and respectively transversely connected between the plurality of columns; and a plurality of support columns are respectively installed on the plurality of cross beams; the storage rack is also provided with: a sand core inlet and a sand core outlet, and a blocker is provided at the sand core outlet to prevent the sand core from sliding out; the crane is located at both sides of the storage rack. The utility model not only can store appropriate sand cores in the storage bin before production, avoiding the problem of waiting for sand cores in the pouring area when the core making equipment changes the mold; moreover, different types of sand cores can be stored in multiple independent areas, greatly improving the production efficiency; at the same time, the pouring area can also selectively pour, which is more flexible in adjusting the production rhythm.

[0005] Patent document 3 (CN209502899U) discloses a drying sand core device, which comprises an oven, a combustion machine arranged on the oven, an oven door arranged on one side of the oven, a tray arranged in the oven, and a sand core arranged on the tray. The parameters of the combustion machine are set according to the different process requirements of the sand core drying. The utility model has the advantages of simple structure, convenient manufacturing, improved product qualification rate, reduced labor intensity, and improved enterprise production efficiency.

[0006] Due to its own characteristics, inorganic sand cores have many problems in use, which limit their development and hinder the progress of green casting. The following points can be summarized:

[0007] ① The initial strength of inorganic sand cores is low, and the sand cores will be transported to the core store immediately after production is completed. During transportation, the sand cores will be broken. How long can the sand cores be transported?

[0008] ② Inorganic sand cores have poor moisture resistance. If the sand cores are not sent to the constant temperature and humidity store in time after production is completed, the strength of the sand cores will decrease due to moisture absorption. How long can the sand cores be sent to the core store after production is completed?

[0009] ③ The usable time of inorganic sand cores is greatly affected by environmental humidity and temperature. If the storage time is too long, the sand cores are easy to break; if the storage time is too short, the production rhythm cannot be guaranteed. At present, the storage time of sand cores in the core store is controlled by experience. How long is the best storage time?

[0010] ④ Due to the moisture absorption of inorganic sand cores, the water content increases. Can the sand cores be used after drying? What is the most appropriate drying temperature and time?

[0011] The above problems often trouble foundry workers during the use of inorganic sand cores. Once not properly controlled, they can cause quality problems, increase the waste core rate or the casting scrap rate. The patent is to help solve the above problems. According to a series of experimental data, the "inorganic sand core use process" is determined. SUMMARY

[0012] The present application overcomes the deficiencies of the prior art. The following data are determined: the strength change of the inorganic sand core during the placing process in the production site after the production is completed. The best storage time in the core warehouse and the storage time in the production site after the production is completed. The moisture and strength change of the inorganic sand core at different times in the core warehouse. The drying process of the inorganic sand core. According to the present application, the waste core rate of the inorganic sand core can be reduced, and the casting scrap rate can be reduced.

[0013] It should be noted that, in the present document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0014] Therefore, the present application provides a control method of inorganic sand core, and the present application provides the following technical solutions:

[0015] A control method of inorganic sand core, the method comprises the following steps:

[0016] Step 1: preparation before preparation, preparation of materials and machine equipment;

[0017] Step 2: sand mixing according to the prepared materials, preparation of sand core;

[0018] Step 3: after the preparation of the sand core is completed, the sand core is detected by experiment, and the tensile strength change of the sample stored in the core warehouse for 24 hours is detected by comparing the samples at different time periods within 6 hours after the sample is placed in the production site; the humidity and temperature of the production site are recorded; "0.5 minute" sample: 6 inorganic sand core samples are prepared, and 3 samples are detected for tensile strength after being placed in the production site for 0.5 hour, and the remaining three samples are stored in the core warehouse according to the standards "I", "II" and "III";

[0019] "1h-6h" sample: each group of samples is prepared for 6 pieces, and placed in the production site for 1 hour, 2 hours...6 hours different time; each group of samples extracts 3 pieces to detect tensile strength, the rest of the sample surface is marked "1-1" "1-2" "1-3" "2-1"...."6-3", placed in the core library.

[0020] Preferably, the step 1 is specifically: material preparation adopts 50 / 100 model of quartz sand, inorganic liquid binder, inorganic powder accelerator;

[0021] Test equipment uses sand mixer, inorganic sample preparation machine, strength tester, infrared temperature measuring gun, infrared oven and one-thousandth balance equipment.

[0022] Preferably, the step 2 is specifically:

[0023] Sand mixing process uses process ratio: each time quartz sand addition amount is 2000g, inorganic binder addition amount is 40g, inorganic accelerator addition amount is 18g;

[0024] Sand mixing sequence: inorganic accelerator is added to quartz sand, and is mixed and rolled for 30 seconds, inorganic binder is added and continues to be mixed and rolled for 60 seconds, and the sand is unloaded;

[0025] Sample preparation process: the core box temperature of inorganic sample preparation machine is 200℃, the blowing temperature is 180℃, the sand shooting time is 3 seconds, and the "8" tensile light sample meets the size requirements.

[0026] Preferably, the step 3 is specifically:

[0027] After the sand core production is completed, the sand core temperature, moisture and strength change every 10 minutes are recorded after the sand core is placed on site for about two hours:

[0028] Record the humidity and temperature at this time;

[0029] "0 minute" sample: after the inorganic sand core sample is taken out, the infrared temperature measuring gun is used to detect the temperature of the sample, and the strength tester is used to detect the tensile strength of the sample, and the average value of the group data is taken as the test data;

[0030] "10 minute" sample: after the inorganic sand core sample is taken out, three samples are weighed by one-thousandth balance, and the last three decimal places are kept, and the sample surface is marked "10-1" "10-2" "10-3", according to the mark, the temperature, tensile strength and weight change of the sample are detected after 10 minutes, and the average value of the group data is taken as the experimental data;

[0031] "20 minute"-"130 minute" sample: according to the detection recording method of "10 minute" sample, and so on.

[0032] Preferably, after the sand core production is completed, it is placed in the field for 30 minutes, and then placed in the core library, and the moisture and strength of the sand core are changed every 1-2 days:

[0033] The temperature of the constant temperature and humidity library is set to 30°C, and the relative humidity is 30%;

[0034] "0 day" sample: after the inorganic sand core sample is taken out, it is placed in the production field for 30 minutes, and the tensile strength at this time is detected;

[0035] "1 day" sample: after the inorganic sand core sample is taken out, it is placed in the production field for 30 minutes, three samples are weighed using a thousandth balance, the decimal point is retained to three places, and "1-1", "1-2", and "1-3" are marked on the surface of the samples and placed in the core library; after being placed in the core library for 1 day, the weight and tensile strength of the data of this group are weighed;

[0036] "2 day" to "15 day" sample: according to the detection recording method of the "1 day" sample, after being placed in the production field for 30 minutes, the weight is weighed and placed in the core library; according to the mark, take out according to the different placement time requirements in the core library, weigh the weight value and tensile strength of each group of data, and detect one group of data every day for 1-7 days, and detect once every 2 days for 8-15 days.

[0037] Preferably, the moisture and strength change of the sample is dried in an oven at 120±10°C for 1h;

[0038] The sample is placed in a constant temperature and humidity library for 24 hours, taken out, and the tensile strength of the sample at this time is detected;

[0039] The weight of the sample is detected before being placed in the oven;

[0040] After the sample is dried in an oven at 120±10°C for 1h, it is taken out, and the weight and tensile strength of the sample are detected;

[0041] The difference between the weight before and after drying is the moisture removed by drying.

[0042] An inorganic sand core control device, wherein a kind of inorganic sand core control method is run on the device.

[0043] An inorganic sand core control system, comprising:

[0044] A preparation preparation module, which performs preparation preparation, prepares materials and machine equipment;

[0045] A sand mixing module, which mixes sand according to the prepared materials to prepare sand cores;

[0046] An experimental module, which detects the sand core after the sand core preparation is completed.

[0047] A computer readable storage medium having stored thereon a computer program, wherein the program is executed by a processor to implement a control method of an inorganic sand core.

[0048] A computer device comprising a memory and a processor, wherein the memory stores a computer program, and wherein the processor implements a control method of an inorganic sand core when executing the computer program.

[0049] The present application has the following beneficial effects:

[0050] After the inorganic sand core is produced, the strength of the sand core gradually increases before the room temperature is restored, and the strength value is the highest when the room temperature is reached at 20 minutes; the sand core strength gradually decreases at 30 minutes. Therefore, the best time for the inorganic sand core to be transported to the core library after being taken out of the box is 20-30 minutes. The sand core is stored on site for 0.5-1 hours, and then is put into the core library for 1-3 days, so that the strength of the sand core can be improved. The sand core is put into the core library for more than 2 hours, and the strength cannot be improved or even restored. The sand core put into the core library is guaranteed to be used up within 3 days, and the sand core will not be damaged. The tensile strength of the inorganic sand core placed in the core library is reduced to below 0.6 MPa on the fourth day, and the sand core will be broken during storage or use, and the moisture content will increase significantly. On the fifth day, the tensile strength is maintained at 0.50-0.55 MPa; the moisture content reaches about 0.06% on the ninth day and does not change. The inorganic sand core placed in an environment with a temperature of 35 DEG C and a relative humidity of 90% for 1 hour can improve the tensile strength and reduce the moisture content after being dried at 100-200 DEG C for 5 minutes. The tensile strength decreases when the drying temperature is 120 DEG C ± 20 DEG C and the drying time is 1 hour.

[0051] 2) Alternative:

[0052] The production site environment and the constant temperature and humidity library of the experiment can be replaced by a constant temperature and humidity box of a laboratory.

[0053] The 50 / 100 quartz sand used in the experiment can be replaced by other types of quartz sand or foundry sand for testing.

[0054] The inorganic binder used in the experiment can be mixed with 10% or less of organic components as a substitute, or a silicate water glass binder can be used as a substitute.

[0055] The strength comparison of the experiment can be replaced by the compressive strength or the bending strength.

[0056] The infrared oven used in the experiment can be replaced by a microwave oven for production. BRIEF DESCRIPTION OF DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the accompanying drawings needed to be used in the specific embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0058] Figure 1 The figure is a schematic diagram of the change curve of moisture, strength, and temperature with time in the production site.

[0059] Figure 2 The figure is a schematic diagram of the change curve of moisture and tensile strength with time in the constant temperature and humidity warehouse.

[0060] Figure 3 The figure is a schematic diagram of the comparison of tensile strength in the site and the core warehouse.

[0061] Figure 4 The figure is a schematic diagram of the comparison of strength after drying for 1 hour.

[0062] Figure 5 The figure is a curve diagram of the optimal drying temperature. DETAILED DESCRIPTION

[0063] The technical solutions of the present application will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the scope of protection of the present application.

[0064] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0065] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. Embodiment one:

[0067] According to Figures 1 to 5 The specific optimization technical scheme adopted by the present application to solve the above technical problems is: the present application relates to a control method of inorganic sand core.

[0068] A control method of inorganic sand core, the method comprising the following steps:

[0069] Step 1: preparation before preparation, preparation of materials and machine equipment;

[0070] Step 2: mixing sand according to the prepared materials, preparing sand core;

[0071] Step 3: after the preparation of the sand core is completed, the sand core is detected by experiment, and after the production of the sand core is completed, the samples in different time periods within 6 hours are placed in the core library for 24 hours, and the change of the tensile strength of the samples is detected: the humidity and temperature of the production site are recorded; "0.5 minute" sample: 6 inorganic sand core samples are prepared, and 3 samples are detected for tensile strength after being placed in the production site for 0.5 hours, and the remaining three samples are stored in the core library according to the standards "I", "II" and "III";

[0072] "1h-6h" sample: 6 samples are prepared in each group, and are placed in the production site for 1 hour, 2 hours...6 hours at different times; 3 samples are detected for tensile strength in each group, and the remaining samples are marked "1-1", "1-2", "1-3", "2-1"...."6-3" on the surface and placed in the core library. Embodiment two:

[0074] The difference between the embodiment two and the embodiment one of the present application is only:

[0075] The step 1 is specifically: the materials are prepared by using 50 / 100 type quartz sand, inorganic liquid binder and inorganic powder accelerator;

[0076] The test equipment adopts sand mixer, inorganic sample preparation machine, strength tester, infrared temperature measuring gun, infrared oven and one-thousandth balance equipment. Embodiment three:

[0078] The difference between the embodiment three and the embodiment two is only that:

[0079] The step 2 is specifically:

[0080] The mixing sand process adopts the process ratio: the quartz sand adding amount is 2000g, the inorganic binder adding amount is 40g, and the inorganic accelerator adding amount is 18g;

[0081] The mixing sand sequence is that the inorganic accelerator is added into the quartz sand, the mixing and grinding is performed for 30 seconds, the inorganic binder is added to continue the mixing and grinding for 60 seconds, and the sand is unloaded;

[0082] The sample preparation process is that the core box temperature of the inorganic sample preparation machine is 200℃, the blowing temperature is 180℃, the sand shooting time is 3 seconds, and the "8" anti-tensile light sample meets the size requirement. The embodiment four is specifically:

[0084] The difference between the embodiment four and the embodiment three is only that:

[0085] The step 3 is specifically:

[0086] After the sand core production is completed, the sand core is placed on site for about two hours, and the sand core temperature, moisture and strength change every 10 minutes:

[0087] The site humidity and temperature at this time are recorded;

[0088] The "0 minute" sample: after the inorganic sand core sample is taken out, the temperature of the sample is detected by using the infrared temperature gun, the anti-tensile strength of the sample is detected by using the strength tester, and the average value of the data of the group is taken as the experimental data;

[0089] The "10 minute" sample: after the inorganic sand core sample is taken out, three samples are weighed by using the one-thousandth balance, the three decimal places are reserved, and the surface of the sample is marked "10-1", "10-2" and "10-3". According to the marking, the temperature, the anti-tensile strength and the weight change of the sample are detected after 10 minutes, and the average value of the data of the group is taken as the experimental data;

[0090] The "20 minute" to "130 minute" sample: according to the detection recording method of the "10 minute" sample, the same is used. The embodiment five is specifically:

[0092] The difference between the embodiment five and the embodiment four is only that:

[0093] After the sand core production is completed, the sand core is placed on site for 30 minutes and is put into the core library, and the sand core moisture and strength change every 1-2 days:

[0094] The temperature of the constant temperature and humidity library is set to 30℃, and the relative humidity is 30%;

[0095] "0 day" sample: after the inorganic sand core sample is taken out, it is placed in the production site for 30 minutes, and the tensile strength at this time is detected;

[0096] "1 day" sample: after the inorganic sand core sample is taken out, it is placed in the production site for 30 minutes, and three samples are weighed using a thousandth balance, the decimal point is retained to three places, and is marked "1-1", "1-2", "1-3" on the surface of the sample, and is placed in the core library; after being placed in the core library for 1 day, the weight and tensile strength of the group are weighed;

[0097] "2 day" to "15 day" sample: according to the detection record method of the "1 day" sample, after being placed in the production site for 30 minutes, the weight is weighed, and is placed in the core library; according to the mark, it is taken out from the core library according to different placement time requirements, and the weight value and tensile strength of each group of data are weighed, wherein 1-7 days detect one group of data every day, and 8-15 days, detect once every 2 days. Specific embodiment six:

[0099] The difference between the embodiment six and the embodiment five is only that:

[0100] The moisture and strength change of the sample is dried in the oven at 120±10℃ for 1h;

[0101] The sample is placed in a constant temperature and humidity library for 24 hours, taken out, and the tensile strength of the sample at this time is detected;

[0102] The weight of the sample is detected before being placed in the oven;

[0103] After the sample is dried in the oven at 120±10℃ for 1h, it is taken out, and the weight and tensile strength of the sample are detected;

[0104] The difference between the weight before and after drying is the moisture removed by drying. Specific embodiment seven:

[0106] The difference between the embodiment seven and the embodiment six is only that:

[0107] The present application provides a kind of control equipment of inorganic sand core, the equipment runs a kind of control method of inorganic sand core. Specific embodiment eight:

[0109] The difference between the embodiment eight and the embodiment seven is only that:

[0110] The present application provides a kind of control system of inorganic sand core, the system includes:

[0111] Preparation preparation module, preparation preparation module carries out preparation, prepares material and machine equipment;

[0112] Sand mixing module, sand mixing module mixes sand according to prepared material, and prepares sand core;

[0113] An experiment module is configured to perform experiment detection on the sand core after the sand core is prepared. Specific embodiment nine:

[0115] The difference between the embodiment nine and the embodiment eight is only that:

[0116] The application provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to implement a control method of inorganic sand cores.

[0117] The method comprises:

[0118] Step 1: preparation before preparation, preparation of materials and machine equipment;

[0119] Step 2: sand mixing according to the prepared materials, and preparation of the sand core;

[0120] Step 3: experiment detection on the sand core after the sand core is prepared, and comparison of the tensile strength changes of the samples placed in the core warehouse for 24 hours within different time periods within 6 hours after the sand core production is completed; the humidity and temperature of the production site are recorded; 0.5-minute samples: six inorganic sand core samples are prepared, and three samples are extracted for tensile strength detection after being placed in the production site for 0.5 hours, and the remaining three samples are stored in the core warehouse according to standards I, II and III.

[0121] 1h-6h samples: six samples are prepared in each group, and are placed in the production site for different time periods of 1 hour, 2 hours, 6 hours and the like; three samples are extracted from each group for tensile strength detection, and the remaining samples are marked as 1-1, 1-2, 1-3, 2-1,..., and 6-3 on the surface, and are placed in the core warehouse. Specific embodiment ten:

[0123] The difference between the embodiment ten and the embodiment nine is only that:

[0124] A computer device comprises a memory and a processor, the memory stores a computer program, and the processor implements a control method of inorganic sand cores when the computer program is executed.

[0125] The method comprises:

[0126] Step 1: preparation before preparation, preparation of materials and machine equipment;

[0127] Step 2: sand mixing according to the prepared materials, and preparation of the sand core;

[0128] Step 3: After the sand core is prepared, the sand core is tested, and the tensile strength of the sample is tested after being placed in the core library for 24 hours. The humidity and temperature of the production site are recorded; "0.5 minute" sample: 6 inorganic sand core samples are prepared, and 3 samples are taken for tensile strength testing after being placed in the production site for 0.5 hours, and the remaining three samples are stored in the core library according to the standards "I", "II", and "III";

[0129] "1h-6h" sample: 6 samples are prepared for each group, and are placed in the production site for 1 hour, 2 hours, and 6 hours respectively; 3 samples are taken for tensile strength testing, and the remaining samples are marked "1-1", "1-2", "1-3", "2-1",..., "6-3" on the surface and placed in the core library.

[0130] Determine the use process of inorganic core - the temperature, moisture, and strength change of the sand core placed in the production site for different times after the core is prepared Figure 1 , wherein the ambient temperature is 30±2℃ and the humidity is 70±3%.

[0131] ① The test data is shown in Figure 1 :

[0132] ② Test conclusion:

[0133] As can be seen from the comparison of the curves, the strength of the core sand reaches the highest value 20 minutes after the core is prepared; the temperature of the sand sample returns to normal after 30 minutes, and the moisture begins to gradually increase.

[0134] Because the moisture of the sand core increases, it will cause porosity defects in the casting; the decrease in strength will cause the sand core to be damaged. Therefore, the sand core should be transported to the core library before the moisture increases and the strength decreases to the critical point of sand core damage. (The critical point of sand core damage is different depending on the structure of the sand core, and is generally 0.5-0.7MPa according to experience).

[0135] Determine the use process of inorganic core - the moisture and strength change of the sand core placed in the core library for different times Figure 2 , wherein the core library temperature is 30℃ and the relative humidity is 30%.

[0136] ① The test data is shown in Figure 2 :

[0137] ② Test conclusion:

[0138] As can be seen from the comparison of the curves, the strength almost does not change within 1 day after being placed in the core library for half a month, the strength begins to decrease rapidly on the second day, the decrease slows down to 0.50-0.55MPa on the fifth day; the moisture significantly increases on the third day, and remains at about 0.06% on the ninth day and does not increase any more.

[0139] The air in the constant temperature and humidity core storage still contains moisture. Therefore, during storage, the sand core absorbs moisture, causing the moisture content to decrease. Once the moisture content reaches the relative humidity equilibrium point and becomes saturated, the strength tends to stabilize.

[0140] Experience shows that as tensile strength decreases below 0.65 MPa, the waste rate of sand cores gradually increases. Furthermore, increased moisture content leads to increased porosity in the casting. Therefore, inorganic sand cores should be used within 3 days of storage in the core storage facility.

[0141] Determining the application process of inorganic sand cores - the effect of different on-site placement times followed by 24 hours in a core silo on sand core performance (core silo temperature 30℃, relative humidity 30%). Figure 3 The ambient temperature was 30±2℃ and the humidity was 70±3%.

[0142] ① Experimental data as follows Figure 3 As shown:

[0143] ② Experimental conclusions:

[0144] Inorganic cores left on-site for 1 hour showed increased strength when placed in the core storage chamber; however, sand cores left for more than 2 hours could not recover their strength when placed in the core storage chamber, and their strength continued to decrease as the on-site placement time increased.

[0145] Due to the high humidity at the site, the surface of the sand core quickly absorbed moisture. After being placed in the core storage, the moisture on the surface of the sand core can be removed by dehumidification. The sand core placed at the site for 1 hour did not affect the bonding bridge due to the moisture absorbed by the sand core.

[0146] If the bonding bridge is damaged after more than 1 hour, the strength cannot be restored. Moisture gradually migrates into the sand core, damaging the bonding bridge and causing a decrease in strength. It cannot be restored even if placed in the core casket.

[0147] Determine the application process of inorganic sand cores - performance changes after drying (drying temperature 120±20℃, drying time 1h), wherein the sand cores are placed in a constant temperature and humidity chamber at 30℃ and 30% relative humidity before drying.

[0148] ① Experimental data as follows Figure 4 As shown:

[0149] ② Experimental conclusions:

[0150] After being stored on-site for different periods and dried at 120±20℃ for 1 hour, the strength of the sand core decreased by 37.3% compared to before drying.

[0151] Because the raw sand used for core making contains moisture, after drying, the moisture is discharged from the surface of the sand grains, which destroys the bonding bridges between the sand grains, resulting in a decrease in the strength of the sand core.

[0152] Further verification was conducted through the experimental conclusions of (3) and (4) to determine whether the strength of the sample could be partially restored and the moisture reduced after it was placed in an oven and quickly dried and removed from the oven after being placed in a high humidity environment for 1 hour. The test was conducted in a constant temperature and humidity chamber with the temperature set at 35℃ and the relative humidity at 90%.

[0153] ② Experimental conclusions:

[0154] The curves from the supplementary experiments show that, after being stored on-site for different periods and dried at 150±50℃ for 5 minutes, the sand core strength increased by 23.2% compared to before drying, and the moisture reduction rate exceeded the moisture absorption rate of the sample after 1 hour.

[0155] The drying temperature and time settings are as follows: Since the maximum temperature of the infrared oven is 200℃, and the temperature fluctuates by at least 50℃ during the drying process (from opening the oven door to inserting the sample to closing it), the intermediate temperature is set at 150℃, and the minimum temperature exceeds 100℃. The minimum operating time is 5 minutes – the shortest possible time to insert the sand core into the oven and immediately remove it after closing the oven door.

[0156] Therefore, when inorganic sand cores are exposed to high temperature and high humidity, the surface absorbs moisture. Rapid drying can reduce the amount of moisture absorbed by the sand core surface and improve the strength of the sand core.

[0157] The above description is merely a preferred embodiment of a method for controlling inorganic sand cores. The scope of protection for a method for controlling inorganic sand cores is not limited to the above embodiments. All technical solutions falling within this conceptual framework are within the scope of protection of this invention. It should be noted that for those skilled in the art, any improvements and variations made without departing from the principles of this invention should also be considered within the scope of protection of this invention.

Claims

1. A method for controlling inorganic sand cores, characterized by: The method includes the following steps: Step 1: Preparation before preparation, including materials and equipment; Step 2: Mix the prepared materials to make sand cores; Step 3: After the sand core is prepared, the sand core is tested. After the sand core is produced, the samples placed on site for 6 hours at different time periods are placed in the core warehouse for 24 hours to test the change in tensile strength of the samples. Record the humidity and temperature of the production site. "0.5 minute" sample: 6 inorganic sand core samples are prepared, placed on the production site for 0.5 hours, 3 samples are taken to test the tensile strength, and the remaining 3 samples are stored in the core warehouse according to the standards "I", "II", and "IIII". "1h-6h" samples: Six samples were prepared for each group and placed at the production site for different times, such as 1 hour, 2 hours...6 hours; Three samples from each group were randomly selected to test tensile strength, and the remaining samples were marked with "1-1", "1-2", "1-3", "2-1", ... "6-3" and placed in the core storage. After the sand cores are produced, they are left on-site for 30 minutes and then placed in the core storage. The moisture content and strength changes of the sand cores are recorded every 1-2 days: The temperature and relative humidity of the constant temperature and humidity chamber were set at 30℃ and 30%; "0-day" sample: After the inorganic sand core sample is taken out, it is placed at the production site for 30 minutes and the tensile strength at this time is tested. "1-day" test: After the inorganic sand core test samples are taken out, they are placed on the production site for 30 minutes. Three test samples are weighed using a 0.1% balance, and three decimal places are retained. The test samples are marked with "1-1", "1-2", and "1-3" and placed in the core storage. After the test samples are placed for 1 day, they are taken out and the weight and tensile strength of the test samples are measured. "2-day" to "15-day" samples: According to the testing and recording method of "1-day" samples, after placing them on the production site for 30 minutes, weigh them and put them into the core storage; according to the markings, take them out of the core storage according to different placement time requirements, weigh the weight value and tensile strength of each set of data, among which one set of data is tested every day from 1 to 7 days, and tested once every 2 days from 8 to 15 days. Changes in moisture content and strength of the sample after drying in an oven at 120±10℃ for 1 hour; The sample was placed in a constant temperature and humidity chamber for 24 hours, then removed and the tensile strength of the sample was tested. The sample is placed in front of the drying oven, and its weight is measured at this time; After drying the sample in an oven at 120±10℃ for 1 hour, remove it and test the weight and tensile strength of the sample. The difference in weight before and after drying is the amount of moisture removed during drying.

2. The method for controlling inorganic sand cores according to claim 1, characterized in that: Step 1 specifically involves: material preparation using 50 / 100 grade quartz sand, inorganic liquid binder, and inorganic powder accelerator; The testing equipment included a sand mixer, a non-mechanical prototype, a strength tester, an infrared thermometer, an infrared oven, and a 0.1 g balance.

3. The method for controlling inorganic sand cores according to claim 2, characterized in that: Step 2 specifically involves: The mixing process uses the following proportions: 2000g of quartz sand, 40g of inorganic binder, and 18g of inorganic accelerator are added each time. Sand mixing sequence: Add inorganic accelerator to quartz sand, mix and grind for 30 seconds, add inorganic binder and continue mixing and grinding for 60 seconds, then unload the sand; The sample preparation process is as follows: the core box temperature of the non-mechanical sampler is 200℃, the air blowing temperature is 180℃, the sand injection time is 3 seconds, and the tensile strength of the figure-eight sample meets the dimensional requirements.

4. The method for controlling inorganic sand cores according to claim 3, characterized in that: Step 3 specifically involves: After the sand cores are produced, they are left on-site for about two hours. The changes in temperature, moisture content, and strength of the sand cores are recorded every 10 minutes: Record the humidity and temperature at this time; "0-minute" test specimen: After the inorganic sand core specimen is taken out, the temperature of the specimen is immediately detected by an infrared thermometer and the tensile strength of the specimen is detected by a strength tester. The average value of this set of data is taken as the test data. "10-minute" test: After the inorganic sand core test specimens are taken out, three test specimens are weighed using a balance with a weight of 1 / 1000, and three decimal places are retained. "10-1", "10-2", and "10-3" are marked on the test specimen surface. According to the markings, the temperature, tensile strength, and weight change of the test specimens are detected after 10 minutes, and the average value of the set of data is taken as the experimental data. "20-minute" to "130-minute" samples: follow the testing and recording method for "10-minute" samples, and so on.

5. A control device for inorganic sand cores, characterized in that, The control device operates the method as described in any one of claims 1-4.

6. A control system for inorganic sand cores, said control system operating based on the control method for inorganic sand cores according to claim 1, characterized in that: The control system includes: The preparation module performs pre-preparation preparation, including preparing materials and machinery / equipment. A sand mixing module, which mixes sand according to the prepared materials to prepare a sand core; The experimental module performs experimental testing on the sand cores after the sand cores are prepared.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method as described in any one of claims 1-4.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the method according to any one of claims 1-4.

Images