Aluminum alloy, forging material, preparation method of forging material, piston, compressor and engine

Abstract

The invention relates to an aluminum alloy, a forging material, a preparation method of the forging material, a piston, a compressor and an engine. The aluminum alloy comprises, by mass, 11%-13% of Si, 0.5%-1.1% of Cu, 0.8%-1.1% of Mg, 0-1.0% of Fe, 0-0.25% of Zn, 0.5%-1.3% of Ni, 0-0.1% of Cr and the balance Al and other inevitable elements. According to the aluminum alloy, the low-Cu and low-Ni alloy component design is adopted, Si, Cu, Mg, Fe, Zn, Ni, Cr and Al in a specific proportion are matched with one another to achieve synergistic interaction, and the comprehensive performance such as the mechanical strength, ductility and corrosion resistance of the material is improved.

Description

Technical Field

[0001] The present application relates to the technical field of metallurgical materials, and in particular to an aluminum alloy, a forging material and a preparation method thereof, a piston, a compressor and an engine. Background Art

[0002] Aluminum alloys are lightweight, which can reduce automobile fuel consumption, reduce carbon emissions, and improve the operating efficiency of the vehicle. At the same time, aluminum alloys also have excellent strength and corrosion resistance, and can provide sufficient structural strength and durability to meet the safety and use requirements of automobiles. Therefore, aluminum alloys are widely used in the automotive manufacturing industry. However, when aluminum alloys are used in some parts with high strength requirements, such as pistons that need to move back and forth at high speed, it is difficult to meet the strength requirements. Summary of the invention

[0003] Based on this, it is necessary to provide aluminum alloys, forging materials and preparation methods thereof, pistons, compressors and engines that can improve strength.

[0004] In one aspect of the present application, an aluminum alloy is provided, which includes the following components in mass percentage: 11%~13% Si, 0.5%~1.1% Cu, 0.8%~1.1% Mg, 0~1.0% Fe, 0~0.25% Zn, 0.5%~1.3% Ni, 0~0.1% Cr, and the rest is Al and other inevitable elements.

[0005] The above-mentioned aluminum alloy is designed with low Cu and low Ni alloy components. Through the specific proportions of Si, Cu, Mg, Fe, Zn, Ni, Cr and Al, the synergistic effects are enhanced to improve the comprehensive properties of the aluminum alloy such as hardness, tensile strength, yield strength and elongation.

[0006] In the above aluminum alloy, controlling Mg to 0.8%~1.1% is beneficial to avoid hot cracking of the material; controlling Si to 11%~13% is beneficial to improving fluidity and reducing hot cracking tendency, thereby improving the casting performance of forging materials; controlling Cu to 0.5%~1.1% is beneficial to strengthening the alloy performance. Cu atoms dissolve into the aluminum matrix to form a solid solution, which will cause lattice distortion and increase the resistance to dislocation movement, thereby significantly improving the strength, hardness and recrystallization temperature of the aluminum alloy. When used at higher temperatures, the Cu-containing aluminum alloy can better maintain the stability and mechanical properties of its organizational structure and is not prone to softening and deformation. This is of great significance for parts that need to work in higher strength and higher temperature environments, such as: some high-temperature parts of automobile engines; 0.8%~1.1% Mg has a higher solid solubility in Al. Mg atoms dissolve into the Al matrix to form a solid solution, which will cause lattice distortion and hinder dislocation movement, thereby improving the strength and hardness of the aluminum alloy, and taking into account the toughness of the aluminum alloy. The mutual cooperation of 11%~13% Si, 0.5%~1.1% Cu, 0.8%~1.1% Mg and 0.5%~1.3% Ni has synergistic effects and improves the comprehensive properties of aluminum alloy, such as mechanical, corrosion resistance and wear resistance.

[0007] In some embodiments, the aluminum alloy comprises the following components by mass percentage: 11% to 13% Si, 0.8% to 1.1% Cu, 0.9% to 1.0% Mg, 0 to 1.0% Fe, 0 to 0.25% Zn, 0.8% to 0.9% Ni, 0 to 0.1% Cr, and the rest is Al and other inevitable elements.

[0008] A second aspect of the present application provides a forging material, wherein the forging material comprises the aluminum alloy as described in the first aspect.

[0009] In some embodiments, the average grain size of the forging material is ≤20µm.

[0010] The third aspect of the present application provides a method for preparing the forging material as described in the second aspect, comprising the following steps:

[0011] Providing a billet, the billet comprising the aluminum alloy according to the first aspect;

[0012] Forging the blank in a die, controlling the temperature of the blank to be 410° C. to 450° C., and controlling the working temperature of the die to be 180° C. to 220° C., to obtain a forging blank of a desired shape;

[0013] The forging blank is quenched at a quenching temperature of 485° C. to 525° C. to obtain the forged material.

[0014] In some embodiments, during the forging process, the temperature of the blank is controlled to be 425° C. to 435° C.; and / or

[0015] Control the working temperature of the mold to 195℃~205℃; and / or

[0016] When performing the quenching treatment, the quenching temperature is controlled to be 500°C-510°C.

[0017] In some embodiments, the following aging treatment step is also included after the quenching treatment:

[0018] The quenched forging blank is heated to 160°C to 170°C; and / or, the holding time is 8 h to 12 h.

[0019] A fourth aspect of the present application provides a piston, which is made of the forging material described in the second aspect or the preparation method of the forging material described in the third aspect.

[0020] A fifth aspect of the present application provides a compressor comprising the piston as described in the fourth aspect.

[0021] A sixth aspect of the present application provides an engine comprising the piston as described in the fourth aspect or the compressor as described in the fifth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a heat treatment curve diagram of the process of preparing a vehicle compressor piston in Example 1.

[0023] FIG. 2 is a metallographic structure diagram of the vehicle compressor piston prepared in Example 1.

[0024] Figure 3 This is a hardness curve of the vehicle compressor piston prepared in Example 1. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0027] Aluminum alloy has good strength and corrosion resistance while being light in weight. Therefore, it is one of the preferred materials for many products with lightweight and low energy consumption requirements. However, when traditional aluminum alloy is used to produce some products with high strength requirements, such as automotive compressor pistons, the strength requirements are difficult to meet, and the production process is complicated and the yield rate is low, which is not conducive to improving production efficiency.

[0028] In one aspect of the present application, an embodiment provides an aluminum alloy, which includes the following components in mass percentage: 11%~13% Si, 0.5%~1.1% Cu, 0.8%~1.1% Mg, 0~1.0% Fe, 0~0.25% Zn, 0.5%~1.3% Ni, 0~0.1% Cr, and the rest is Al and other inevitable elements.

[0029] The above-mentioned aluminum alloy is designed with low Cu and low Ni alloy components. Through the specific proportions of Si, Cu, Mg, Fe, Zn, Ni, Cr and Al, the hardness, tensile strength, yield strength and elongation of the aluminum alloy are synergistically enhanced.

[0030] In the above aluminum alloy, controlling Mg to 0.8%~1.1% is beneficial to avoid hot cracking of the material; controlling Si to 11%~13% is beneficial to improving fluidity and reducing hot cracking tendency, thereby improving the casting performance of forging materials; controlling Cu to 0.5%~1.1% is beneficial to strengthening the alloy performance. Cu atoms dissolve into the aluminum matrix to form a solid solution, which will cause lattice distortion and increase the resistance to dislocation movement, thereby significantly improving the strength, hardness and recrystallization temperature of the aluminum alloy. When used at higher temperatures, the Cu-containing aluminum alloy can better maintain the stability and mechanical properties of its organizational structure and is not prone to softening and deformation. This is of great significance for parts that need to work in higher strength and higher temperature environments, such as: some high-temperature parts of automobile engines; 0.8%~1.1% Mg has a higher solid solubility in Al. Mg atoms dissolve into the Al matrix to form a solid solution, which will cause lattice distortion and hinder dislocation movement, thereby improving the strength and hardness of the aluminum alloy, and taking into account the toughness of the aluminum alloy. The mutual cooperation of 11%~13% Si, 0.5%~1.1% Cu, 0.8%~1.1% Mg and 0.5%~1.3% Ni has synergistic effects and improves the comprehensive properties of aluminum alloy, such as mechanical, corrosion resistance and wear resistance.

[0031] As an example, the mass percentage of Si in the aluminum alloy can be 11%, 11.1%, 11.2%, 11.3%, 11.4%, 11.5%, 11.6%, 11.7%, 11.8%, 11.9%, 12%, 12.1%, 12.2%, 12.3%, 12.4%, 12.5%, 12.6%, 12.7%, 12.8%, 12.9% and 13%, or within a range consisting of any two of the foregoing values ​​as end values.

[0032] As an example, the mass percentage of Cu in the aluminum alloy can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0% and 1.1%, or a range consisting of any two of the above values ​​as end values. The mass percentage of Cu in the aluminum alloy is preferably 0.8% to 1.1%.

[0033] As an example, the mass percentage of Mg in the aluminum alloy can be 0.8%, 0.9%, 1.0% and 1.1%, or a range consisting of any two of the above values ​​as end values. The mass percentage of Mg in the aluminum alloy is preferably 0.9% to 1.0%.

[0034] As an example, the mass percentage of Fe in the aluminum alloy can be 0, 0.1%, 0.18%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% and 1.0%, or a range consisting of any two of the above values ​​as end values. The mass percentage of Fe in the aluminum alloy is preferably 0-0.18%.

[0035] As an example, the mass percentage of Zn in the aluminum alloy can be 0, 0.01%, 0.02%, 0.1%, 0.2% and 0.25%, or a range consisting of any two of the aforementioned values ​​as end values. The mass percentage of Zn in the aluminum alloy is preferably 0-0.02%.

[0036] As an example, the mass percentage of Ni in the aluminum alloy can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2% and 1.3%, or a range consisting of any two of the above values ​​as end values. The mass percentage of Ni in the aluminum alloy is preferably 0.8% to 0.9%.

[0037] As an example, the mass percentage of Cr in the aluminum alloy can be 0, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% and 0.1%, or a range consisting of any two of the above values ​​as end values. The mass percentage of Cr in the aluminum alloy is preferably 0-0.05%.

[0038] In some embodiments, the aluminum alloy comprises the following components by mass percentage: 11% to 13% Si, 0.8% to 1.1% Cu, 0.9% to 1.0% Mg, 0 to 1.0% Fe, 0 to 0.25% Zn, 0.8% to 0.9% Ni, 0 to 0.1% Cr, and the rest is Al and other inevitable elements.

[0039] In some embodiments, the total mass percentage of the inevitable other elements is ≤0.15%, and the mass percentage of a single element of the inevitable other elements is ≤0.05%.

[0040] Furthermore, Mn, Ti, and Sr element tracking is performed according to the following conditions: among other unavoidable elements, the mass percentage of a single element is ≤0.05%, and the total mass percentage of all elements is ≤0.15%.

[0041] A second aspect of the present application provides a forging material, wherein the forging material comprises the aluminum alloy as described in the first aspect.

[0042] In the forging material, the metallographic structure of the forging material is optimized by controlling the composition and content of the billet, so that the average grain size of the grain is ≤20µm, there is no segregation or overburning phenomenon, the grains are refined, and the metallographic structure of the grains is uniform and fine. The forging material adopts the alloy composition design of low Cu and low Ni to obtain higher strength and heat resistance of the forging material; in the forging material, controlling Mg to 0.8%~1.1% can avoid thermal cracking of the material; the specific proportion of Si, Cu, Mg, Fe, Zn, Ni, Cr and Al in the forging material cooperates with each other, synergistically enhances the effect, refines the grains, and improves the hardness, tensile strength, yield strength, elongation, corrosion resistance and wear resistance of the forging material.

[0043] In the above-mentioned forging materials, the blank composition is precisely controlled. 11%~13% Si can improve fluidity and reduce the tendency of hot cracking, thereby improving the casting performance of the forging material; 0.5%~1.1% Cu can strengthen the alloy performance. During the forging process of aluminum alloy, Cu atoms dissolve into the aluminum matrix to form a solid solution, which will cause lattice distortion and increase the resistance of dislocation movement, thereby significantly improving the strength, hardness and recrystallization temperature of the aluminum alloy. When used at higher temperatures, Cu-containing aluminum alloys can better maintain the stability and mechanical properties of their organizational structure and are not prone to softening and deformation. This is of great significance for aluminum alloy forging parts that need to work in a high temperature environment, such as some high-temperature parts of automobile engines; 0.8%~1.1% Mg has a higher solid solubility in Al. During the forging of aluminum alloy, Mg atoms dissolve into the Al matrix to form a solid solution, which will cause lattice distortion and hinder dislocation movement, thereby improving the strength and hardness of the aluminum alloy, and taking into account the toughness of the aluminum alloy. When the aluminum alloy contains 0.8%~1.1% Mg and undergoes appropriate heat treatment, Mg It will form compounds with Al and other elements and precipitate as fine dispersed second phase particles. These particles can effectively hinder dislocation movement and further improve the strength and hardness of the alloy. In addition, 0.8%~1.1% Mg is beneficial to reducing the density of aluminum alloy and achieving lightweight material.

[0044] In the above-mentioned forging materials, 11%~13% Si, 0.5%~1.1% Cu, 0.8%~1.1% Mg and 0.5%~1.3% Ni cooperate with each other to form a dense oxide film on the surface of the aluminum alloy. The specific elements work together under specific ratios to help form a denser and more protective oxide film on the surface of the aluminum alloy. This oxide film can effectively isolate the contact between the external corrosive medium and the aluminum alloy matrix, thereby significantly improving the corrosion resistance and wear resistance of the aluminum alloy. Moreover, the interaction between Ni and Si, Cu and Mg can form some hard phases on the surface of the aluminum alloy, which can increase the surface hardness of the aluminum alloy, thereby enhancing its wear resistance.

[0045] In the above-mentioned forging materials, 0.5%~1.3% Ni can serve as a heterogeneous nucleation core to promote grain refinement. The fine grain structure can improve the comprehensive mechanical properties of aluminum alloys, such as strength, toughness and fatigue resistance. At the same time, it can also improve its processing performance, make the forging process smoother, and reduce the occurrence of forging defects.

[0046] In some embodiments, the average grain size of the forging material is ≤20µm.

[0047] The average grain size of the forged material is ≤20µm. When the grains are small, dislocation movement needs to bypass more grain boundaries during stress, which increases the resistance to dislocation movement, thereby improving the yield strength and tensile strength of the forged material. In addition, the fine grains make the surface of the forged material denser, reduce the pores and defects on the surface, and reduce the probability of adhesion and intrusion of corrosive media on the surface. At the same time, the uniform microstructure also helps to form a more stable and continuous passivation film, thereby improving the corrosion resistance of the forged material.

[0048] Furthermore, the average grain size of the forging material is 0.1µm~20µm.

[0049] As an example, the average grain size of the forging material is 0.1µm, 0.5µm, 1µm, 2µm, 3µm, 4µm, 5µm, 6µm, 7µm, 8µm, 9µm, 10µm, 11µm, 12µm, 13µm, 14µm, 15µm, 16µm, 17µm, 18µm, 19µm and 20µm, or a range consisting of any two of the above values ​​as end values. The average grain size of the forging material is preferably 4µm to 6µm. The forging material under this average grain size has extremely strong strength, wear resistance, corrosion resistance and dimensional stability.

[0050] The third aspect of the present application provides a method for preparing the forging material as described in the second aspect, comprising the following steps:

[0051] Providing a billet, the billet comprising the aluminum alloy according to the first aspect;

[0052] Forging the blank in a die, controlling the temperature of the blank to be 410° C. to 450° C., and controlling the working temperature of the die to be 180° C. to 220° C., to obtain a forging blank of a desired shape;

[0053] The forging blank is quenched at a quenching temperature of 485° C. to 525° C. to obtain the forged material.

[0054] During the forging stage, the temperature of the billet is controlled at 410℃~450℃, and the working temperature of the die is controlled at 180℃~220℃, which can maintain a suitable temperature difference between the die and the billet, which can not only ensure that the billet can be in a good plastic deformation state throughout the forging process, but also improve the corrosion resistance of the forging material. On this basis, the quenching temperature of 485℃~525℃ is further combined to obtain a uniformly organized forging material, which not only avoids the risk of deformation and cracking of the forging material, but also makes the forging material have excellent mechanical properties and corrosion resistance.

[0055] As an example, the temperature of the blank can be 410°C, 411°C, 412°C, 413°C, 414°C, 415°C, 416°C, 417°C, 418°C, 419°C, 420°C, 421°C, 422°C, 423°C, 424°C, 425°C, 426°C, 427°C, 428°C, 429°C, 430°C, 431°C, 432°C, 433°C, 434°C, 435°C, 436°C, 437°C, 438°C, 439°C, 440°C, 441°C, 442°C, 443°C, 444°C, 445°C, 446°C, 447°C, 448°C, 449°C and 450°C, or any two of the above values ​​as end values. The temperature of the blank is preferably 425°C to 435°C.

[0056] As an example, the working temperature of the mold can be 180°C, 181°C, 182°C, 183°C, 184°C, 185°C, 186°C, 187°C, 188°C, 189°C, 190°C, 191°C, 192°C, 193°C, 194°C, 195°C, 196°C, 197°C, 198°C, 199°C, 200°C, 201°C, 202°C, 203°C, 204°C, 205°C, 206°C, 207°C, 208°C, 209°C, 210°C, 211°C, 212°C, 213°C, 214°C, 215°C, 216°C, 217°C, 218°C, 219°C and 220°C, or in the range formed by any two of the above values ​​as end values. The working temperature of the mold is preferably 195°C to 205°C.

[0057] As an example, the quenching temperature can be 485°C, 486°C, 487°C, 488°C, 489°C, 490°C, 491°C, 492°C, 493°C, 494°C, 495°C, 496°C, 497°C, 498°C, 499°C, 500°C, 501°C, 502°C, 503°C, 504°C, 505°C, 506°C, 507°C, 508°C, 509°C, 510°C, 511°C, 512°C, 513°C, 514°C, 515°C, 516°C, 517°C, 518°C, 519°C, 520°C, 521°C, 522°C, 523°C, 524°C and 525°C, or in the range formed by any two of the foregoing values ​​as end values. The quenching temperature is preferably 500°C to 510°C.

[0058] In some embodiments, during the forging process, the temperature of the blank is controlled to be 425°C to 435°C. Controlling the temperature of the blank at 425°C to 435°C is conducive to refining the grain structure and reducing internal defects. At this temperature, the grains inside the blank will undergo dynamic recrystallization during the deformation process, and the newly formed grains will be finer and more uniform; in addition, the deformation resistance of the forging material can be significantly reduced, the requirements and losses on the forging equipment can be reduced, and the forging operation can be facilitated to proceed more smoothly.

[0059] In some embodiments, when the forging is performed, the working temperature of the mold is controlled to be 195° C. to 205° C. Controlling the working temperature of the mold to be 195° C. to 205° C. can improve the fluidity of the metal, which is conducive to better filling the mold cavity with aluminum alloy, ensuring that the shape of the forging is more complete and the size is more accurate, and reducing defects such as lack of meat and flash caused by poor metal flow; at this temperature, it is also conducive to refining the grain structure and reducing residual stress.

[0060] In some embodiments, when the quenching treatment is performed, the quenching temperature is controlled to be 500° C. to 510° C. At this quenching temperature, the solute atoms in the aluminum alloy can form a supersaturated solid solution in the matrix, increasing the resistance to dislocation movement, thereby ultimately improving the strength of the forged material; at this temperature, it is not only conducive to forming a denser and more stable oxide film on the surface of the forged material, effectively preventing the external medium from corroding the inside of the forged material, but also at this temperature, the composition and distribution of the internal phase of the aluminum alloy can be optimized, further improving the corrosion resistance of the aluminum alloy.

[0061] Furthermore, during the forging stage, the temperature of the billet is controlled at 425℃~435℃, and the working temperature of the mold is controlled at 195℃~205℃, so that a more appropriate temperature difference can be maintained between the mold and the billet, which can not only ensure that the billet can be in a good plastic deformation state throughout the forging process, but also improve the corrosion resistance of the forging material.

[0062] Furthermore, during the forging stage, the temperature of the billet is controlled at 425℃~435℃, the working temperature of the mold is 195℃~205℃, and the quenching temperature is 500℃~510℃, so that a forging material with a more uniform structure is obtained, which further improves the strength and corrosion resistance of the forging material.

[0063] In some embodiments, during the forging stage, the temperature of the blank is 190° C. to 270° C. higher than the working temperature of the die. Under this temperature difference, the forged material has good plasticity and is not prone to deformation and cracking.

[0064] Furthermore, during the forging stage, the temperature of the blank is 220°C to 240°C higher than the die working temperature. Under this temperature difference, the forged material has better plasticity, is not easy to deform and crack, and has excellent dimensional stability.

[0065] In some of the embodiments, a receiving inspection step is further included before forging: the length of the cast rod used is 5±0.05m.

[0066] In some of the embodiments, before forging, a blanking step is further included: cutting the cast rod into rods with a length of 97 (+1,0) mm.

[0067] In some of the embodiments, a forging machine may be used to perform vertical forging and simultaneous vertical forging on both sides of the cast rod, so that the forging blank is piston-shaped.

[0068] In some embodiments, the quenching treatment is carried out for a holding time of 4 to 6 hours. A quenching holding time of 4 to 6 hours can make the Mg and Si elements evenly distributed in the aluminum lattice, reduce component segregation, and thus make the metallographic structure of the entire forging material more uniform after quenching.

[0069] As an example, the holding time of the quenching treatment can be 4h, 4.5h, 5.0h, 5.5h and 6.0h, or within a range consisting of any two of the aforementioned values ​​as end values.

[0070] In some embodiments, the cooling medium of the quenching treatment is water at 35° C. to 40° C.; and / or the cooling time of the quenching treatment is 2 min to 3 min.

[0071] In some embodiments, the following aging treatment step is also included after the quenching treatment:

[0072] The quenched forging blank is heated to 160℃~170℃; and / or, the holding time is 8 h~12 h. The aging treatment at this temperature or holding time will make the forging material show better fracture resistance and surface hardness.

[0073] In some embodiments, the billet is a cast rod.

[0074] In some embodiments, the quenching or aging treatment is performed using thermocouple heating.

[0075] In some embodiments, the aging treatment is followed by natural cooling.

[0076] In some embodiments, the following shock-polishing treatment step is also included after the aging treatment:

[0077] The forging blank after aging treatment is subjected to vibration polishing treatment, wherein the vibration polishing time is 60min-70min; and / or, the abrasive for the vibration polishing treatment is brown corundum oblique triangular abrasive.

[0078] The above-mentioned shock-polishing treatment can improve the surface finish of the forged material, enhance the corrosion resistance and wear resistance, and can also eliminate the internal stress of the forged material, stabilize the dimensional accuracy of the forging, improve the fatigue resistance of the forged material, make it less likely to crack when subjected to cyclic loads, and extend the service life. The forged material has no burrs or aluminum chips on the surface and has a uniform surface color.

[0079] In some embodiments, a machining step is further included after the shock-polishing treatment: the heat-treated forged material is subjected to machining such as turning the overall length, chamfering, drilling, etc. to obtain a semi-finished product.

[0080] In some embodiments, a cleaning step is further included after the machining step: the machined semi-finished product is subjected to spray cleaning, ultrasonic cleaning, ultrasonic rinsing, pure water rinsing and then drying to obtain a finished product.

[0081] In some embodiments, the following demolding step is further included after the forging and before the quenching treatment:

[0082] Demolding is performed using a release agent, wherein the release agent includes N-780 forging release agent, DM-5 graphite emulsion and water; and / or, the mass ratio of the N-780 forging release agent, DM-5 graphite emulsion and water is 1:1~3:14~16.

[0083] Furthermore, the mass ratio of the N-780 forging release agent, DM-5 graphite emulsion and water is 1:2:15. Demolding with the release agent can make the surface of the forging material denser and reduce the pores and defects on the surface.

[0084] A fourth aspect of the present application provides a piston, which is made of the forging material described in the second aspect or the preparation method of the forging material described in the third aspect.

[0085] The above piston is not limited to automotive compressor pistons and engine pistons. The automotive compressor piston has excellent tensile strength and yield strength, and high elongation performance, which can meet the performance of automotive compressors and the reliability and commerciality requirements of the whole vehicle, especially the piston strength can be increased by more than 30% compared with the traditional piston strength.

[0086] A fifth aspect of the present application provides a compressor comprising the piston as described in the fourth aspect.

[0087] A sixth aspect of the present application provides an engine comprising the piston as described in the fourth aspect or the compressor as described in the fifth aspect.

[0088] The following are specific embodiments.

[0089] Example 1

[0090] A method for preparing a vehicle compressor piston comprises the following steps:

[0091] (1) Billet composition design

[0092] The billet is a cast rod, and the composition of the cast rod is designed to contain the following components in mass percentage in addition to Al and inevitable impurities with a total amount of ≤0.15%: 11% Si, 1.1% Cu, 1.0% Mg, 0.18% Fe, 0.02% Zn, 0.9% Ni, and 0.01% Cr.

[0093] (2) Inspection of the acceptance of cast bars

[0094] The casting rods used in production have a length of 5 mm ± 0.05m, a height of 38.5 mm ± 0.2mm, and a width of 12.4 mm ± 0.1mm;

[0095] (3) Cutting

[0096] Cut the cast rod into bars with a length of 97 (+1,0) mm. The saw blade specifications for cutting are Ø380×40×1.75×2.0×60T. The saw blade life processing needs to be controlled within 8000 pieces.

[0097] (4) Forging

[0098] A T-type forging press is used. The pressure forging press uses graphite mixed oil, with a tonnage of 400 T in the vertical direction and 315 T in the lateral direction. The bar is forged vertically and vertically on both sides at the same time, so that the forging blank is piston-shaped;

[0099] During forging, the die working temperature is maintained at 200°C, the bar temperature is maintained at 430°C, the main cylinder pressure holding time is 2S, the ejection pressure is 8MPa, the return pressure is 5MPa, the die life shall not exceed 80,000 pieces, and the release agent concentration ratio is: water, DM-5 graphite emulsion, N-780 forging release agent (15:2:1);

[0100] (5) Heat treatment

[0101] Please refer to Figure 1. The heat treatment quenching temperature is 505℃, the quenching holding time is 5h, and then it is completely immersed in water within 10s. After cooling in water, the water pump is stirred for 3min, and the water temperature is controlled at 38℃; the time interval between quenching and aging in the furnace is 2h, that is: natural cooling for 2h and then aging treatment, aging treatment is 165℃ insulation for 10h, and natural cooling is carried out after leaving the furnace;

[0102] The heat treatment furnace is placed layer by layer, with 170 to 175 pieces on each layer. There are 2550 to 2625 pieces evenly placed on 15 layers. At the same time, in order to ensure that the temperature uniformity is within 5°C, a multi-channel temperature controller is used for monitoring;

[0103] (6) Shock throw

[0104] In order to ensure that the piston blank has no burrs, aluminum chips, and the surface color is uniform, brown corundum oblique triangular abrasive is used, and 160±20 pieces are weighed and loaded into the furnace each time, and the material is unloaded after vibrating and polishing for 60min~70min;

[0105] During the process, use a measuring cup to add 15L of water and 1.5L of cleaning agent (LQ-104), and add 25kg (3*3) and 15kg (8*8) for every 100,000 pieces of polishing.

[0106] (7) Machining

[0107] The forged blank after vibration polishing is machined by turning the overall length, turning the chamfer, drilling and other processes to obtain a semi-finished piston;

[0108] (8) Cleaning

[0109] In order to ensure the reliability of the later assembly to the automotive compressor, the machined semi-finished piston is spray cleaned, ultrasonic cleaned, ultrasonic rinsed, rinsed with pure water and then dried. The cleaning speed is 600r / min ~700r / min to obtain the finished piston.

[0110] Aluminum alloy cleaning agent (HX-840) should be used for spray cleaning. The amount added to the slot is 8-10L, the pH value is 2-4, and 5-7L is added every day. The tank liquid should be replaced once every 3 shifts.

[0111] Ultrasonic cleaning requires the use of aluminum alloy cleaning agent (HX-840) with a slot addition amount of 20~25L, a pH value of 2~4, a temperature of 55℃±5℃, and the tank liquid is replaced once per shift;

[0112] Ultrasonic rinsing requires pure water temperature: 60℃~70℃, and the bath liquid is changed twice per shift (8 hours);

[0113] Pure water rinsing requires pure water temperature: 70℃~80℃, and the bath liquid is changed twice per shift (8 hours);

[0114] Finally, it was dried at 130°C with an oven speed of 1500 r / min.

[0115] Example 2

[0116] Example 2 is basically the same as Example 1, except that the composition of the cast rod is designed to contain the following components in mass percentage in addition to Al and inevitable impurities with a total amount of ≤0.15%: 12% Si, 0.8% Cu, 0.9% Mg, 0.5% Fe, 0.1% Zn, 0.8% Ni, and 0.05% Cr.

[0117] Example 3

[0118] Example 3 is basically the same as Example 1, except that the composition of the cast rod is designed to contain the following components in mass percentage in addition to Al and inevitable impurities with a total amount of ≤0.15%: 13% Si, 0.5% Cu, 0.8% Mg, 1.0% Fe, 0.25% Zn, 1.3% Ni, and 0.1% Cr.

[0119] Example 4

[0120] Example 4 is basically the same as Example 1, except that the quenching temperature is 525°C.

[0121] Example 5

[0122] Example 5 is basically the same as Example 1, except that the working temperature of the die during forging is 220°C.

[0123] Example 6

[0124] Example 6 is basically the same as Example 1, except that the temperature of the blank is controlled to be 450°C during forging.

[0125] Comparative Example 1

[0126] Comparative Example 1 is substantially the same as Example 1, except that the mass percentage of Cu element in the blank of the forging material is 3%.

[0127] Comparative Example 2

[0128] Comparative Example 2 is substantially the same as Example 1, except that the mass percentage of Ni element in the blank of the forging material is 4%.

[0129] The hardness, tensile strength, yield strength and elongation of the automotive compressor pistons prepared in Examples 1 to 6 and Comparative Examples 1 to 2 were tested (test standard: GB / T 228.1-2021). The test results are shown in Table 1 below.

[0130] Table 1

[0131]

[0132] From Table 1 above, it can be seen that the automotive compressor pistons prepared in Examples 1 to 6 have high mechanical strength and good toughness. From Figure 2, it can be seen that the automotive compressor piston prepared in Example 1 has a metallographic structure with uniform and fine grains. Figure 3 It can be seen that the hardness of the vehicle compressor pistons prepared in Example 1 reaches about 75.

[0133] It can be seen from Comparative Examples 1 and 2 that the strength, ductility and microstructure of forgings not within the alloy composition range of the present application cannot achieve the effects of the present application.

[0134] By comparing the embodiments, it can be seen that during forging, the temperature of the blank is controlled to be 425°C~435°C, the working temperature of the mold is controlled to be 195°C~205°C, or the quenching temperature is controlled to be 500°C~510°C during quenching treatment, so that a vehicle compressor piston with better comprehensive performance can be obtained.

[0135] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An aluminum alloy, characterized in that: The aluminum alloy includes the following components by mass percentage: 11% to 13% Si, 0.5% to 1.1% Cu, 0.8% to 1.1% Mg, 0 to 1.0% Fe, 0 to 0.25% Zn, 0.5% to 1.3% Ni, 0 to 0.1% Cr, and the rest is Al and other inevitable elements.

2. The aluminum alloy according to claim 1, characterized in that The aluminum alloy includes the following components by mass percentage: 11% to 13% Si, 0.8% to 1.1% Cu, 0.9% to 1.0% Mg, 0 to 1.0% Fe, 0 to 0.25% Zn, 0.8% to 0.9% Ni, 0 to 0.1% Cr, and the rest is Al and other inevitable elements.

3. A forging material, characterized in that: The forging material includes the aluminum alloy as claimed in any one of claims 1 to 2.

4. The forging material according to claim 3, characterized in that The average grain size of the forging material is ≤20µm.

5. A method for preparing a forging material according to any one of claims 3 to 4, characterized in that: The following steps are involved: Providing a blank, wherein the blank comprises the aluminum alloy according to any one of claims 1 to 2; Forging the blank in a die, controlling the temperature of the blank to be 410° C. to 450° C., and controlling the working temperature of the die to be 180° C. to 220° C., to obtain a forging blank of a desired shape; The forging blank is quenched at a quenching temperature of 485° C. to 525° C. to obtain the forged material.

6. The method for preparing a forging material according to claim 5, characterized in that: During the forging process, the temperature of the blank is controlled to be 425° C. to 435° C.; and / or Control the working temperature of the mold to 195℃~205℃; and / or When performing the quenching treatment, the quenching temperature is controlled to be 500°C-510°C.

7. The method for preparing a forging material according to any one of claims 5 to 6, characterized in that: After the quenching treatment, the following aging treatment steps are also included: The quenched forging blank is heated to 160°C to 170°C; and / or, the holding time is 8 h to 12 h.

8. A piston, characterized in that: The forging material is made by the forging material described in any one of claims 3 to 4 or by the preparation method of the forging material described in any one of claims 5 to 7.

9. A compressor, characterized in that: Comprising a piston as claimed in claim 8.

10. An engine, characterized in that: Comprising a piston as claimed in claim 8 or a compressor as claimed in claim 9.

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