阅读说明：本技术 铝合金压铸机用高温结构陶瓷料管的生产工艺 (Production process of high-temperature structural ceramic material pipe for aluminum alloy die casting machine ) 是由 王传学 周正方 于 2021-08-17 设计创作，主要内容包括：本发明涉及铝合金压铸机用高温结构陶瓷料管的生产工艺,该工艺包括原料准备、研磨制浆、工件成型、生坯干燥、高温烧成、陶瓷内外圆加工、金属固定套安装、打码包装；所述原料准备中原料为氧化锆、氧化铝、碳化硅、氮化硅、氧化钙、氧化镁、氮化硼和氧化钇；将预混好的配合料和研磨球装入高速球磨机中；向高速球磨机中加入去离子水,研磨搅拌均匀后再加入助剂,研磨搅拌制得浆料；所述工件成型工艺为注浆法成型、注凝法成型、等静压成型工艺中的一种。该陶瓷材质大幅度地提高了料管的耐合金熔液的腐蚀性、耐磨性,满足了部分非超高压应用场景对料管的力学性能要求,该料管导热系数低,制造周期短,使用时无需额外使用冷却装置,维护成本低。(The invention relates to a production process of a high-temperature structural ceramic material pipe for an aluminum alloy die casting machine, which comprises the steps of raw material preparation, grinding and pulping, workpiece forming, green body drying, high-temperature firing, ceramic inner and outer circle processing, metal fixing sleeve mounting, coding and packaging; the raw materials in the raw material preparation are zirconium oxide, aluminum oxide, silicon carbide, silicon nitride, calcium oxide, magnesium oxide, boron nitride and yttrium oxide; loading the premixed batch and grinding balls into a high-speed ball mill; adding deionized water into a high-speed ball mill, grinding and stirring uniformly, then adding an auxiliary agent, grinding and stirring to obtain slurry; the workpiece forming process is one of slip casting, coagulation casting and isostatic pressing. The ceramic material greatly improves the corrosion resistance and the wear resistance of alloy melt of the material pipe, meets the mechanical property requirements of partial non-ultrahigh pressure application scenes on the material pipe, and has the advantages of low heat conductivity coefficient, short manufacturing period, no need of additionally using a cooling device during use and low maintenance cost.)

1. The production process of the high-temperature structure ceramic material pipe for the aluminum alloy die casting machine is characterized by comprising the following operation steps of: preparing S1 raw materials, grinding and pulping S2, forming an S3 workpiece, drying an S4 green body, sintering the S5 at a high temperature, processing the inner and outer circles of S6 ceramic, installing an S7 metal fixing sleeve, and coding and packaging S8;

the raw materials prepared in the S1 raw material preparation are zirconium oxide, aluminum oxide, silicon carbide, silicon nitride, calcium oxide, magnesium oxide, boron nitride and yttrium oxide;

in the S2 grinding and pulping process, the premixed batch and grinding balls are put into a high-speed ball mill, and the using amount of the grinding balls is 30-400% of the mass of the batch; adding deionized water accounting for 45-150% of the mass of the batch materials into a high-speed ball mill, grinding and stirring uniformly, then adding an auxiliary agent, grinding and stirring to obtain slurry;

the S3 workpiece forming process is one of slip casting method forming, slip casting method forming and isostatic pressing forming.

2. The production process of the high-temperature structural ceramic material pipe for the aluminum alloy die casting machine as recited in claim 1, wherein the production process comprises the following steps: the raw materials of zirconia, alumina, silicon carbide, silicon nitride, calcium oxide, magnesium oxide, boron nitride and yttrium oxide in the S1 raw material preparation comprise, by mass, 65-97% of stabilized zirconia and monoclinic zirconium and 3-36% of alpha-Al₂O₃1-12% of silicon carbide micro powder, 1-6% of silicon nitride micro powder, 2.7-4.6% of calcium oxide micro powder, 2-3.8% of magnesium oxide micro powder, 0.2-7.5% of boron nitride micro powder and 0.3-2.1% of yttrium oxide micro powder;

the raw materials are respectively added into a mixer and premixed for 10-45 minutes to form a batch.

3. The production process of the high-temperature structural ceramic material pipe for the aluminum alloy die casting machine as recited in claim 1, wherein the production process comprises the following steps: when the S3 workpiece is molded by adopting a slip casting method and an isostatic pressing process, the auxiliary agent in the S2 grinding and pulping process consists of polyvinyl alcohol and one of aluminum dimaleate phosphate or propyl hydroxymethyl cellulose; adding deionized water into the batch, grinding and stirring uniformly, adding 0.4-6% of polyvinyl alcohol, 0.2-2% of aluminum dihydrogen phosphate or propyl hydroxymethyl cellulose, and adding 30-400% of zirconia grinding balls; grinding and stirring at a grinding speed of 200-400 rpm for 15-40 minutes to obtain slurry;

when the S3 workpiece is molded by adopting an injection coagulation molding process, the auxiliary agent in the S2 grinding pulping comprises an acrylamide monomer, a cross-linking agent, a dispersing agent and an initiator; adding deionized water into the batch, grinding and stirring uniformly, adding an acrylamide monomer, a cross-linking agent and a dispersing agent, grinding and stirring for 15-40 minutes at a grinding speed of 200-400 rpm, then adding an initiator, and stirring for 0.5-5 minutes to obtain slurry.

4. The production process of the high-temperature structural ceramic material pipe for the aluminum alloy die casting machine as recited in claim 3, wherein: when the S3 workpiece is molded by an isostatic pressing process, the slurry obtained by grinding and pulping the S2 material also comprises S2-1 spray drying granulation, the slurry is put into a storage tank of a spray granulator, the air temperature is set to be 150-300 ℃, spray drying granulation is carried out, a granulated material with the main granularity of 0.1-1.5 mm is prepared, and the water content of the qualified granulated material is 0.5-1.1%; and sealing the qualified granulated material at the temperature of 25-35 ℃, ageing the material for 24-36 hours, and then carrying out S3 workpiece forming operation.

5. The production process of the high-temperature structural ceramic material pipe for the aluminum alloy die casting machine as recited in claim 1, wherein the production process comprises the following steps:

when the S3 workpiece is formed by adopting an isostatic pressing process, an assembling die with an inner core made of quenched steel and an outer die made of hard rubber or high-elasticity polyurethane is adopted as a forming die; weighing qualified granulated materials with proper weight, injecting the qualified granulated materials into a mould, vibrating the mould for 10 to 30 seconds by using a high-frequency vertical vibration type vibration table, supplementing the granulated materials in the mould to a proper height, and sealing the mould; placing the die into a high-pressure cylinder of an isostatic press, pressurizing to 60-250 Mpa, keeping for 3-15 minutes, releasing pressure, taking out and demoulding; naturally drying the demolded blank for 20-48 hours, and then carrying out S4 green body drying operation;

when the S3 workpiece is molded by adopting an injection-coagulation method, an aluminum alloy is adopted as a molding die, the molding die made of the aluminum alloy is placed in a vacuum box, the prepared slurry is stirred for 15-60 minutes under the vacuum condition, the slurry after vacuum treatment is injected into the molding die, then the molded die after injection molding is placed in a drying box with the temperature of 80-100 ℃ for curing for 1.5-2 hours, the molded die is removed and demoulded to form a molded blank, the molded blank is naturally dried after curing, and the green blank is naturally dried for 20-48 hours and then is dried in S4;

when the S3 workpiece is molded by adopting a slip casting method, gypsum is adopted to mold a molding die, the molding die is placed in a vacuum box, the prepared slurry is stirred for 15-60 minutes under the vacuum condition, the slurry after vacuum treatment is injected into the molding die, then the molding die after injection molding is placed in a curing room with the temperature of 20-35 ℃ and the relative humidity of 65-85% for curing for 24-36 hours, and demolding is carried out to form a molding blank; and (4) naturally drying the formed blank after curing, and carrying out S4 green body drying operation after naturally drying for 20-48 hours.

6. The production process of the high-temperature structural ceramic material pipe for the aluminum alloy die casting machine as recited in claim 1, wherein the production process comprises the following steps: in the S4 green body drying process, the highest drying temperature is 240-275 ℃; wherein the heating speed of two heating intervals of heating from 75 ℃ to 125 ℃ and from 160 ℃ to 200 ℃ is not higher than 2-5 ℃/h; keeping the temperature at the maximum drying temperature of 240-275 ℃ for 4-10 hours, and drying the green body for 42-48 hours.

7. The production process of the high-temperature structural ceramic material pipe for the aluminum alloy die casting machine as recited in claim 1, wherein the production process comprises the following steps: in the S5 high-temperature sintering process, a high-temperature box furnace or a tunnel type high-temperature kiln with a high-temperature silicon-molybdenum rod as a heating element is adopted for sintering; the highest firing temperature of the high-temperature box furnace or the tunnel type high-temperature kiln is 1520-1780 ℃, the temperature rise speed is controlled to be 5-10 ℃/h, and the heat is preserved for 7-12 h at the highest temperature; step cooling is carried out after sintering, the two steps are naturally cooled from the highest temperature to 1200 ℃ and from 900 ℃ to normal temperature, and the cooling speed is not more than 10 ℃/hour when the temperature is reduced from 1200 ℃ to 900 ℃; and taking out the ceramic blank from the high-temperature box furnace or the tunnel type high-temperature kiln when the temperature of the ceramic blank is reduced to normal temperature.

8. The production process of the high-temperature structural ceramic material pipe for the aluminum alloy die casting machine as recited in claim 7, wherein the production process comprises the following steps: in the S5 high-temperature sintering process, zirconia sand with the thickness of 5-10 mm and the granularity of 0.2-1 mm is uniformly laid on a hearth for placing a ceramic blank in a high-temperature box furnace or a tunnel type high-temperature kiln, and then the ceramic blank dried by the S4 green body is horizontally and stably placed on the zirconia sand; the distance between the adjacent ceramic blanks is not less than 15 mm; the distance between the heating body and the ceramic blank is not less than 15 mm.

9. The production process of the high-temperature structural ceramic material pipe for the aluminum alloy die casting machine as recited in claim 1, wherein the production process comprises the following steps: in the process of processing the inner circle and the outer circle of the ceramic material pipe of S6, a diamond cutting machine or a lathe is adopted to cut the end of a fired ceramic blank according to the set length of the ceramic material pipe, and the end face is vertical to the central axis of the ceramic blank during cutting; carrying out rough machining on the inner circle and the outer circle of the ceramic by adopting a diamond turning tool, and controlling the machining allowance of a workpiece to be 0.1-0.2 mm; continuously grinding and finely processing the inner surface and the outer surface of the workpiece by using a high-precision inner and outer circular grinder, wherein the grinding size precision does not exceed +/-2 threads;

in the S7 metal fixing sleeve mounting process, a fixing sleeve manufactured by processing high-strength die steel is sleeved on a specified position of a ceramic material pipe according to the material pipe mounting size specified by a user;

in the S8 code printing and packaging process, the production management number of the product is printed on the product by adopting laser code printing or other reliable modes, and then the product is packaged.

10. The production process of the high-temperature structural ceramic material pipe for the aluminum alloy die casting machine as recited in claim 1, wherein the production process comprises the following steps: the thickness of the ceramic material pipe is 25-60 mm.

Technical Field

The invention belongs to the technical field of aluminum alloy casting industry, and particularly relates to a production process of a high-temperature structure ceramic material pipe for an aluminum alloy die casting machine.

Background

The aluminum alloy die casting machine is a molding device which quickly pressurizes and injects molten high-temperature aluminum alloy after melting and refining into a die and forms an aluminum alloy casting after cooling. At present, 70% of aluminum alloy castings are produced by a high-pressure cold chamber die casting mode, a soup ladle is adopted in the production process to pour smelted aluminum alloy melt into a material pipe from a material pipe pouring gate, an injection head at the tail end of the material pipe is pushed by an injection rod, the melt in the material pipe is pushed into a die through three process steps of slow injection, fast injection and pressurization, aluminum liquid is rapidly cooled and formed in the die, and the injection head returns to the tail end of the material pipe to restart the operation of the next period. The material pipe is a key consumable part used on an aluminum alloy high-pressure cold chamber die casting machine, service performance indexes such as service life, performance stability and the like of the material pipe influence the operating efficiency of the die casting machine and the production qualification rate of die castings decisively.

At present, a material pipe for an aluminum alloy die casting machine is mostly processed and manufactured by adopting a hot-work die steel H13 bar, and the production process comprises bar cutting, electric spark punching, lathe roughing, quenching, tempering, and nitriding treatment after internal and external processing; wherein, because the hot die steel H13 bar is a solid bar in the bar cutting, the strength is high, the processing is difficult, the time and the labor are wasted, and the utilization rate of raw materials is only 45% -60%; after internal stress of the quenched and tempered material is eliminated, the hardness of the quenched and tempered material can only reach HRC 42-48; in order to ensure the requirements of the size precision and the surface smoothness of the inner diameter of the material pipe, a rough machining workpiece which deforms in the quenching and tempering processes needs to be ground, the grinding time is long, and the processing cost is high; the nitriding process of the hot-work die steel H13 takes 3-5 days, and the equipment investment and the manufacturing cost of a production plant are greatly increased. The surface hardness of the material pipe after the nitriding treatment is improved, and the service life is prolonged. However, after long-term use, the surface hardness will gradually age and fatigue fail, and the gate part length time is affected by chemical corrosion and abrasion of the alloy melt and deformation caused by uneven heating of the inner surface, which results in damage to the material pipe.

Compared with high-temperature ceramics, the H13 metal material tube has the defects of poor corrosion resistance, high heat conductivity coefficient, large reduction of thermal-state mechanical property in a high-temperature state and the like, so that the problems that die castings produced by an aluminum alloy high-pressure cold chamber die casting machine are common in slag inclusion, the backflow probability of alloy melt during injection is high, the material tube is frequently replaced, the rejection rate of initial-replacement castings is high, the casting manufacturing cost is high and the like cannot be effectively solved. Along with but the aluminum alloy spare application of die-casting is more and more extensive, commercial die casting machine tonnage is bigger and bigger, and material pipe life is shorter and shorter, and present biggest die casting machine tonnage has reached 8000 tons, corresponds the life of material pipe and only has several thousand moulds, needs frequently to change the material pipe.

In order to prolong the service life of the material pipe on a large-tonnage die casting machine, people try to adopt heat-resistant alloy steel imported from Germany and having better corrosion resistance and better thermodynamic property to manufacture the material pipe, and practical tests prove that the service life of the material pipe reaches 2-3 times of that of the H13 material pipe, but the manufacturing cost of the material pipe reaches nearly 20 times of that of the H13 material pipe, so that the material pipe has no practical application value.

Disclosure of Invention

The technical problem solved by the invention is as follows: aiming at the defects, the invention provides the production process of the high-temperature structure ceramic material pipe for the aluminum alloy die casting machine, which greatly improves the corrosion resistance and the wear resistance of the alloy melt of the material pipe, meets the mechanical property requirements of the material pipe in non-ultrahigh pressure application scenes, and has the advantages of small heat conductivity coefficient, low manufacturing cost, short production period, no need of an additional cooling device during use and low maintenance cost.

The technical scheme adopted by the invention for solving the technical problems is as follows: the production process of the high-temperature structure ceramic material pipe for the aluminum alloy die casting machine comprises the following operation steps: preparing S1 raw materials, grinding and pulping S2, forming an S3 workpiece, drying an S4 green body, sintering the S5 at a high temperature, processing the inner and outer circles of S6 ceramic, installing an S7 metal fixing sleeve, and coding and packaging S8;

the raw materials prepared in the S1 raw material preparation are zirconium oxide, aluminum oxide, silicon carbide, silicon nitride, calcium oxide, magnesium oxide, boron nitride and yttrium oxide;

in the S2 grinding and pulping process, the premixed batch and grinding balls are put into a high-speed ball mill, and the using amount of the grinding balls is 30-400% of the mass of the batch; adding deionized water accounting for 45-150% of the mass of the batch materials into a high-speed ball mill, grinding and stirring uniformly, then adding an auxiliary agent, grinding and stirring to obtain slurry;

the S3 workpiece forming process is one of slip casting method forming, slip casting method forming and isostatic pressing forming.

Further, zirconia, alumina, silicon carbide, silicon nitride, calcium oxide, magnesium oxide, boron nitride, and yttrium oxide in the S1 raw material preparation; the raw material components comprise, by mass, 65-97% of stabilized zirconia and monoclinic zirconium and 3-36% of alpha-Al₂O₃1-12% of silicon carbide micro powder, 1-6% of silicon nitride micro powder, 2.7-4.6% of calcium oxide micro powder, 2-3.8% of magnesium oxide micro powder, 0.2-7.5% of boron nitride micro powder and 0.3-2.1% of yttrium oxide micro powder;

the raw materials are respectively added into a mixer and premixed for 10-45 minutes to form a batch.

Further, when the S3 workpiece is molded by adopting a slip casting method or an isostatic pressing process, the auxiliary agent in the S2 grinding pulping is composed of polyvinyl alcohol and one of aluminum dimalephosphate or propylhydroxymethylcellulose; adding deionized water into the batch, grinding and stirring uniformly, adding 0.4-6% of polyvinyl alcohol, 0.2-2% of aluminum dihydrogen phosphate or propyl hydroxymethyl cellulose, and adding 30-400% of zirconia grinding balls; grinding and stirring at a grinding speed of 200-400 rpm for 15-40 minutes to obtain slurry;

when the S3 workpiece is molded by adopting an injection coagulation molding process, the auxiliary agent in the S2 grinding pulping comprises an acrylamide monomer, a cross-linking agent, a dispersing agent and an initiator; adding deionized water into the batch, grinding and stirring uniformly, adding an acrylamide monomer, a cross-linking agent and a dispersing agent, grinding and stirring for 15-40 minutes at a grinding speed of 200-400 rpm, then adding an initiator, and stirring for 0.5-5 minutes to obtain slurry.

Furthermore, when the S3 workpiece is molded by an isostatic pressing process, the slurry obtained by grinding and pulping the S2 material also comprises S2-1 spray drying granulation, the slurry is put into a storage tank of a spray granulator, the air temperature is set to be 150-300 ℃, and spray drying granulation is carried out to obtain a granulated material with the main granularity of 0.1-1.5 mm, and the water content of the qualified granulated material is 0.5-1.1%; and sealing the qualified granulated material at the temperature of 25-35 ℃ for ageing for 24-36 hours, and then carrying out S3 workpiece forming operation.

Furthermore, when the S3 workpiece is formed by adopting an isostatic pressing process, a combined die with an inner core made of quenched steel and an outer die made of hard rubber or high-elasticity polyurethane is used as a forming die; weighing qualified granulated materials with proper weight, injecting the qualified granulated materials into a mould, vibrating the mould for 10 to 30 seconds by using a high-frequency vertical vibration type vibration table, supplementing the granulated materials in the mould to a proper height, and sealing the mould; placing the die into a high-pressure cylinder of an isostatic press, pressurizing to 60-250 Mpa, keeping for 3-15 minutes, releasing pressure, taking out and demoulding; naturally drying the demolded blank for 20-48 hours, and then carrying out S4 green body drying operation;

when the S3 workpiece is molded by adopting an injection-coagulation method, an aluminum alloy is adopted as a molding die, the molding die made of the aluminum alloy is placed in a vacuum box, the prepared slurry is stirred for 15-60 minutes under the vacuum condition, the slurry after vacuum treatment is injected into the molding die, then the molded die after injection molding is placed in a drying box with the temperature of 80-100 ℃ for curing for 1.5-2 hours, the molded die is removed and demoulded to form a molded blank, the molded blank is naturally dried after curing, and the green blank is naturally dried for 20-48 hours and then is dried in S4;

when the S3 workpiece is molded by adopting a slip casting method, gypsum is adopted to mold a molding die, the molding die is placed in a vacuum box, the prepared slurry is stirred for 15-60 minutes under the vacuum condition, the slurry after vacuum treatment is injected into the molding die, then the molding die after injection molding is placed in a curing room with the temperature of 20-35 ℃ and the relative humidity of 65-85% for curing for 24-36 hours, and demolding is carried out to form a molding blank; and (4) naturally drying the formed blank after curing, and carrying out S4 green body drying operation after naturally drying for 20-48 hours.

Furthermore, in the drying process of the S4 green body, the maximum drying temperature is 240-275 ℃; wherein the heating speed of two heating intervals of heating from 75 ℃ to 125 ℃ and from 160 ℃ to 200 ℃ is not higher than 2-5 ℃/h; keeping the temperature at the maximum drying temperature of 240-275 ℃ for 4-10 hours, and drying the green body for 42-48 hours.

Further, in the S5 high-temperature firing process, a high-temperature box furnace or a tunnel type high-temperature kiln using a high-temperature silicon-molybdenum rod as a heating element is used for firing; the highest firing temperature of the high-temperature box furnace or the tunnel type high-temperature kiln is 1520-1780 ℃, the temperature rise speed is controlled to be 5-10 ℃/h, and the heat is preserved for 7-12 h at the highest temperature; step cooling is carried out after sintering, the two steps are naturally cooled from the highest temperature to 1200 ℃ and from 900 ℃ to normal temperature, and the cooling speed is not more than 10 ℃/hour when the temperature is reduced from 1200 ℃ to 900 ℃; and taking out the ceramic blank from the high-temperature box furnace or the tunnel type high-temperature kiln when the temperature of the ceramic blank is reduced to normal temperature.

Furthermore, in the S5 high-temperature firing process, zirconia sand with the thickness of 5-10 mm and the granularity of 0.2-1 mm is uniformly laid on a hearth for placing a ceramic blank in a high-temperature box furnace or a tunnel type high-temperature kiln, and then the ceramic blank dried by the S4 green body is horizontally and stably placed on the zirconia sand; the distance between the adjacent ceramic blanks is not less than 15 mm; the distance between the heating body and the ceramic blank is not less than 15 mm.

Further, in the process of processing the inner circle and the outer circle of the ceramic material pipe of S6, cutting the end of the ceramic blank fired by a diamond cutting machine or a lathe according to the set length of the ceramic material pipe, wherein the end surface is perpendicular to the central axis of the ceramic blank during cutting; carrying out rough machining on the inner circle and the outer circle of the ceramic by adopting a diamond turning tool, and controlling the machining allowance of a workpiece to be 0.1-0.2 mm; continuously grinding and finely processing the inner surface and the outer surface of the workpiece by using a high-precision inner and outer circular grinder, wherein the grinding size precision does not exceed +/-2 threads;

in the S7 metal fixing sleeve mounting process, a fixing sleeve manufactured by processing high-strength die steel is sleeved on a specified position of a ceramic material pipe according to the material pipe mounting size specified by a user;

in the S8 code printing and packaging process, the production management number of the product is printed on the product by adopting laser code printing or other reliable modes, and then the product is packaged.

Further, the thickness of the ceramic material pipe is 25-60 mm.

The invention has the beneficial effects that:

1. the ceramic material pipe prepared by the application has the advantages that the corrosivity and the wear resistance of alloy melt of the material pipe are greatly improved, the mechanical property requirement of part of non-ultrahigh pressure application scenes on the material pipe is met, and the service life of the material pipe is prolonged. The material pipe has the advantages of low heat conductivity coefficient, good high-temperature mechanical property, no need of additionally arranging a cooling device during use, low use cost and short production period of the material pipe.

2. The ceramic material pipe is a structural ceramic material made of zirconia, alumina, silicon carbide, magnesia, yttria, silicon nitride and the like, has high temperature resistance, corrosion resistance and wear resistance and low heat conductivity coefficient, the heat conductivity coefficient of the ceramic material pipe is 1/9-1/10 of the metal material of the existing H13 material, the temperature of alloy melt can be reduced by about 30-50 ℃, energy is saved, the quality of castings is improved, the service life of a die-casting die is prolonged, and the cold shut rejection rate of castings at the initial stage of pipe replacement is reduced; the heat loss of the alloy melt in the material pipe is reduced, energy can be saved, semi-solid die casting is realized, the density and the strength of die castings are improved, the quality of the die castings is improved, and the die casting efficiency is improved by about 25-40%.

3. The high-temperature structure ceramic material pipe has high chemical corrosion resistance of aluminum alloy, hardly generates chemical reaction with alloy melt at the use temperature, can greatly prolong the service life of the material pipe, and avoids the pollution of the material pipe material to the alloy melt.

4. The high-temperature structural ceramic material tube has the advantages of good high-temperature mechanical property, no deformation in a thermal state, high hardness and good wear resistance, the mechanical property of the high-temperature structural ceramic material tube is about 1.6-2.7 times that of the existing H13 material, and the hardness and the wear resistance are basically not thermally attenuated, so that the die-casting operation stability is good, and the molten alloy does not flow back when the injection head is pressurized and ejected.

5. When the ceramic material pipe is used, a cooling facility is not required to be configured, so that the use and maintenance cost is reduced; the whole structure of the material pipe is simple, and the manufacturing cost is low and is only 70-85% of the metal material of the existing H13 material.

6. The production cycle of the ceramic material pipe is short, the production cycle of the ceramic material pipe is about 5-8 days, and is reduced by about two thirds compared with the production cycle of 19-23 days of a traditional metal material pipe, so that the emergency requirement of a customer can be better met, and the stock of spare parts of the customer can be reduced.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The production process of the high-temperature structure ceramic material pipe for the aluminum alloy die casting machine comprises the following operation steps of S1 raw material preparation, S2 grinding and pulping, S3 workpiece forming, S4 green body drying, S5 high-temperature firing, S6 ceramic inner and outer circle processing, S7 metal fixing sleeve mounting, and S8 code printing and packaging;

preparing S1 raw material:

the raw materials prepared in the S1 raw material preparation are zirconium oxide, aluminum oxide, silicon carbide, silicon nitride, calcium oxide, magnesium oxide, boron nitride and yttrium oxide; the raw material components comprise, by mass, 65-97% of stabilized zirconia and monoclinic zirconium and 3-36% of alpha-Al₂O₃1-12% of silicon carbide micro powder, 1-6% of silicon nitride micro powder, 2.7-4.6% of calcium oxide micro powder, 2-3.8% of magnesium oxide micro powder, 0.2-7.5% of boron nitride micro powder and 0.3-2.1% of yttrium oxide micro powder; the stability of the stabilized zirconia is 60-80%; adding the raw materials into a mixing machine respectively, and premixing for 10-45 minutes to form a batch; preferably, 67% stabilized zirconia and monoclinic zirconium and 13.8% alpha-Al are selected₂O₃The raw materials of the fine powder, 8.0% of silicon carbide fine powder, 5.2% of silicon nitride fine powder, 2.7% of calcium oxide fine powder, 2.1% of magnesium oxide fine powder, 0.8% of boron nitride fine powder and 0.4% of yttrium oxide fine powder were mixed by a mixer for 30 minutes.

S2 grinding and pulping:

the premixed batch and grinding balls are put into a high-speed ball mill, and the using amount of the grinding balls is 30-400% of the mass of the batch; the high-speed ball mill adopts a zirconia working lining; adding deionized water accounting for 45-150% of the mass of the batch materials into a high-speed ball mill, grinding and stirring uniformly, then adding an auxiliary agent, grinding and stirring at a grinding speed of 200-400 rpm, and preparing slurry; the S3 workpiece forming process is one of slip casting method forming, slip casting method forming and isostatic pressing forming;

(1) when the S3 workpiece is molded by adopting a slip casting method or an isostatic pressing process, the auxiliary agent in the S2 grinding pulping is composed of polyvinyl alcohol and one of aluminum dimalephosphate or propyl hydroxymethyl cellulose; adding deionized water into the batch, grinding and stirring uniformly, adding 0.4-6% of polyvinyl alcohol, 0.2-2% of aluminum dihydrogen phosphate or propyl hydroxymethyl cellulose, and adding 30-400% of zirconia grinding balls; grinding and stirring for 15-40 minutes at a grinding speed of 200-400 r/min, preferably 2.5 Wt% of polyvinyl alcohol and 0.7 Wt% of aluminum dihydrogen phosphate or propylhydroxymethyl cellulose, and grinding and stirring for 30 minutes to obtain slurry;

(2) when the S3 workpiece is molded by adopting a casting and condensing method molding process, the auxiliary agent in the S2 grinding and pulping process comprises an acrylamide monomer, a methylene bisacrylamide crosslinking agent, a JS281 dispersing agent and an ammonium persulfate initiator; the method comprises the steps of adding deionized water into a batch, grinding and stirring uniformly, then adding an acrylamide monomer, a methylene bisacrylamide cross-linking agent and a JS281 dispersing agent, grinding and stirring for 15-40 minutes at a grinding speed of 200-400 rpm, preferably stirring for 30 minutes, then adding an ammonium persulfate initiator, stirring for 0.5-5 minutes, preferably stirring for 3 minutes, and thus obtaining slurry.

S2-1 spray drying and granulating:

when the S3 workpiece is molded by an isostatic pressing process, the slurry obtained by grinding and pulping the S2 material also comprises S2-1 spray drying granulation, the slurry is put into a storage tank of a spray granulator, the air temperature is set to be 150-300 ℃, spray drying granulation is carried out, and the granulated material with the main granularity of 0.1-1.5 mm is prepared, wherein the water content of the qualified granulated material is 0.5-1.1%; and sealing the qualified granulated material at the temperature of 25-35 ℃ for ageing for 24-36 hours, and then carrying out S3 workpiece forming operation, wherein the ageing temperature is preferably 30 +/-2 ℃.

S3 workpiece forming:

the S3 workpiece forming process is one of slip casting method forming, slip casting method forming and isostatic pressing forming; wherein the molding by the grouting method and the casting coagulation method is pressureless casting molding, the volume density ratio of the produced product, and the likeThe static pressure forming is about 0.16 to 0.21g/cm lower³And air holes are easily formed in the molding process.

(1) When the S3 workpiece is formed by adopting an isostatic pressing process, a combined die with an inner core of 20Gr and a No. 45 quenched steel and an outer die made of hard rubber or high-elastic polyurethane is used as a forming die; weighing qualified granulated materials with proper weight, injecting the qualified granulated materials into a mould, vibrating the mould for 10 to 30 seconds by using a high-frequency vertical vibration type vibration table, supplementing the granulated materials in the mould to a proper height, and sealing the mould; placing the die into a high-pressure cylinder of an isostatic press, pressurizing to 60-250 Mpa, keeping for 3-15 minutes, releasing pressure, taking out and demoulding; naturally drying the demolded blank for 20-48 hours, and then carrying out S4 green body drying operation;

(2) when the injection-solidification molding process is adopted for molding the S3 workpiece, aluminum alloy is used as a molding die, and the sintering shrinkage expansion length of the molding die is set to be 5-10%; placing a forming die made of aluminum alloy in a vacuum box, stirring the prepared slurry for 15-60 minutes, preferably for 20 minutes under the condition that the vacuum degree is not more than-90 KPa, injecting the slurry subjected to vacuum treatment into the forming die, then placing the forming die subjected to injection molding in a drying box at the temperature of 80-100 ℃ for curing for 1.5-2 hours, removing and demolding to form a formed blank, naturally drying the formed blank after curing, and naturally drying for 20-48 hours and then performing S4 green body drying operation; specifically, the formed blank can be naturally dried after being maintained for more than 8 hours under the condition of keeping the relative humidity of 80-70%, and forced drying of green blank drying of S4 can be carried out after being naturally dried for 24 hours;

(3) when the S3 workpiece is molded by adopting a slip casting method, a molding die is molded by adopting gypsum, and the sintering shrinkage expansion rule of the molding die is set to be 5-7%; placing a forming die in a vacuum box, stirring the prepared slurry for 15-60 minutes, preferably for 30 minutes under the condition that the vacuum degree is not more than-90 KPa, injecting the vacuum-treated slurry into the forming die, then placing the forming die after injection molding in a curing room with the temperature of 20-35 ℃ and the relative humidity of 65-85% for curing for 24-36 hours, and demolding to form a forming blank; the molded blank is naturally dried after being maintained, and the green blank is dried by S4 after being naturally dried for 20 to 48 hours; specifically, the green body is continuously maintained for 24-36 hours under the condition of keeping 80-70% of relative humidity, so that the green body can be naturally dried, and after the green body is naturally dried for 24 hours, forced drying of drying the green body S4 can be carried out.

S4 green drying:

in the S4 green body drying operation, an electrothermal blowing drying box (kiln) is used for forced drying; the highest drying temperature is 240-275 ℃, and the optimal highest drying temperature is 260 ℃; wherein the temperature rise speed of two temperature rise intervals of raising the temperature from 75 ℃ to 125 ℃ and raising the temperature from 160 ℃ to 200 ℃ is not higher than 2-5 ℃/h, and the preferable temperature rise speed is not higher than 3 ℃/h; keeping the temperature at the drying temperature of 240-275 ℃ for 4-10 hours, wherein the total drying time of the green body is 42-48 hours, and the water content of the dried ceramic green body is less than 0.1 percent.

S5, high-temperature sintering:

in the S5 high-temperature sintering process, a high-temperature box furnace or a tunnel type high-temperature kiln with a high-temperature silicon-molybdenum rod as a heating element is adopted for sintering; uniformly paving zirconia sand with the thickness of 5-10 mm and the granularity of 0.2-1 mm on a platform for placing a ceramic blank in a high-temperature box furnace or a tunnel type high-temperature kiln, and then horizontally and stably placing the ceramic blank dried by the S4 green body on the zirconia sand; the distance between the adjacent ceramic blanks is not less than 15 mm; the distance between the heating body and the ceramic blank is not less than 15 mm; preferably, the distance between the adjacent ceramic blanks is not less than 30 mm; the distance between the heating body and the ceramic blank is not less than 30 mm; the highest firing temperature of the high-temperature box furnace or the tunnel type high-temperature kiln is 1520-1780 ℃, and the temperature is different according to different ceramic material pipes; controlling the temperature rise speed at 5-10 ℃/h, preferably 8 ℃/h, keeping the temperature at the highest temperature for not less than 7 hours, and preferably keeping the temperature for not less than 8 hours; step cooling is carried out after sintering, the two steps are naturally cooled from the highest temperature to 1200 ℃ and from 900 ℃ to normal temperature, and the cooling speed is not more than 10 ℃/hour when the temperature is reduced from 1200 ℃ to 900 ℃; and taking out the ceramic blank from the high-temperature box furnace or the tunnel type high-temperature kiln when the temperature of the ceramic blank is reduced to normal temperature.

S6 processing the inner circle and the outer circle of the ceramic:

in the process of processing the inner circle and the outer circle of the ceramic material pipe of S6, a diamond cutting machine or a lathe is adopted to cut the end of a fired ceramic blank according to the set length of the ceramic material pipe, and the end face is vertical to the central axis of the ceramic blank during cutting; the method comprises the following steps of performing rough machining on the inner circle and the outer circle of the ceramic by adopting a diamond turning tool, controlling smaller feed amount and feed speed during machining by using the diamond turning tool so as to improve machining precision, and controlling the machining allowance of a workpiece to be 0.1-0.2 mm; and (3) continuously grinding and finely processing the inner surface and the outer surface of the workpiece by using a high-precision inner and outer circular grinder, wherein the grinding tool is made of diamond, the grinding size precision does not exceed +/-2 wires, and the thickness of the processed ceramic material pipe is 25-60 mm.

S7 installation of a metal fixing sleeve:

in order to install the ceramic material pipe on the fixed large plate of the die casting machine safely and reliably, a metal fixing sleeve with a mounting flange needs to be installed on the ceramic material pipe. And designing and processing the metal fixing sleeve according to the installation size requirement of the material pipe of a user. The metal fixing sleeve is processed by using high-strength die steel, an inner hole of the fixing sleeve is subjected to finish machining grinding, and the matching size precision of the fixing sleeve and the ceramic material pipe is smaller than 0.05 mm. The ceramic material pipe and the metal fixing sleeve are installed together in a tight fit mode.

S8 coding and packaging:

printing the production management number of the ceramic material pipe on the specified position of the ceramic material pipe by adopting laser coding or other reliable modes, and then packaging the ceramic material pipe

Through detection, the performance indexes of the ceramic material pipe obtained by the production process of the ceramic material pipe are as follows: bending strength not less than 600MPa, and fracture toughness greater than 7Mpa M^1/2Hardness not less than HRC80, thermal shock stability (no crack at 700 deg.C), and bulk density not less than 4.8g/cm³The apparent porosity is not more than 12%. The listed product performance indexes are standard values detected by sampling for multiple times, and when the related performance indexes of the product are lower than the index values, the physical use requirements of some users can be met.

The product is commonly called as a 'pressure chamber, a melting cup' in the academic world and the equipment manufacturing industry, aluminum alloy die-casting production and operation enterprises are commonly called as a 'material pipe, a material cylinder, a material groove' and the like, and the product is called as the 'material pipe' in the invention, and the fundamental property and the characteristic of the product cannot be changed no matter which name is used.

The use of the high-temperature structural ceramic material greatly improves the corrosion resistance and the wear resistance of the alloy melt of the material pipe, thereby prolonging the service life of the material pipe. On the occasion that the set pressurizing pressure of the die casting machine is not particularly high, the tensile strength of the die casting machine can completely meet the mechanical requirement under the use working condition; the heat conductivity coefficient of the ceramic material pipe is 2.2-3.1W/m.k, and is only about 10% of the heat conductivity coefficient of H13 of 28.8W/m.k, so that the feeding temperature of alloy melt can be greatly reduced, energy is saved, the quality of castings is improved, the service life of die casting molds is prolonged, and the cold insulation rejection rate of castings at the initial stage of pipe replacement is reduced; the manufacturing period of the ceramic material pipe is short, the spare goods quantity of a user can be reduced, and the emergency requirement of the user can be met; when in use, a cooling device is not needed, and the use and maintenance cost of a user is reduced.

In addition, the ceramic material tube can be made of structural ceramics such as recrystallized silicon carbide, silicon nitride combined silicon carbide and the like, and has good high temperature resistance, corrosion resistance and wear resistance, but has the defect of high heat conductivity coefficient; the material can also be made of zirconia toughened alumina ceramics, the heat conductivity coefficient is about 1.5-2 times of that of the material, and the main defect is poor corrosion resistance. In the grinding and pulping process, a wheel-grinding type mixer or a variable-frequency high-speed mixing granulator can be used for semi-dry mixing, but the uniformity of pug used for forming is relatively poor, so that the quality uniformity and the service life of a ceramic material pipe are poor and unstable. The high-temperature firing process can also use a gas high-temperature furnace (kiln) for firing, and has the defect of slightly poor temperature uniformity in the furnace. The material can also be sintered by adopting a vacuum or atmosphere (filled with inert gas) furnace, and the sintering requirement can be met, but the configuration cost and the use cost of the sintering equipment are much higher.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.