CN108796316B - Piston made of aluminum-based composite material for heavy-duty diesel engine and preparation method of piston - Google Patents

Piston made of aluminum-based composite material for heavy-duty diesel engine and preparation method of piston Download PDF

Info

Publication number
CN108796316B
CN108796316B CN201810606664.0A CN201810606664A CN108796316B CN 108796316 B CN108796316 B CN 108796316B CN 201810606664 A CN201810606664 A CN 201810606664A CN 108796316 B CN108796316 B CN 108796316B
Authority
CN
China
Prior art keywords
piston
aluminum
melt
composite material
tib
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201810606664.0A
Other languages
Chinese (zh)
Other versions
CN108796316A (en
Inventor
汪明亮
王建忠
王鹏举
吴浩
马乃恒
王浩伟
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anhui Xiangbang Composite Material Co ltd
Shanghai Jiaotong University
Original Assignee
Anhui Xiangbang Composite Material Co ltd
Shanghai Jiaotong University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anhui Xiangbang Composite Material Co ltd, Shanghai Jiaotong University filed Critical Anhui Xiangbang Composite Material Co ltd
Priority to CN201810606664.0A priority Critical patent/CN108796316B/en
Publication of CN108796316A publication Critical patent/CN108796316A/en
Application granted granted Critical
Publication of CN108796316B publication Critical patent/CN108796316B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
    • C22C21/04—Modified aluminium-silicon alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/06—Making non-ferrous alloys with the use of special agents for refining or deoxidising
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/10—Alloys containing non-metals
    • C22C1/1036—Alloys containing non-metals starting from a melt
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/10—Alloys containing non-metals
    • C22C1/1036—Alloys containing non-metals starting from a melt
    • C22C1/1047—Alloys containing non-metals starting from a melt by mixing and casting liquid metal matrix composites
    • C22C1/1052—Alloys containing non-metals starting from a melt by mixing and casting liquid metal matrix composites by mixing and casting metal matrix composites with reaction
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
    • C22C32/0047—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents
    • C22C32/0073—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents only borides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/0084—Pistons  the pistons being constructed from specific materials

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Composite Materials (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

The invention discloses a piston made of an aluminum-based composite material for a heavy-duty diesel engine and a preparation method thereof, wherein the piston comprises a piston body, and the piston body is made of the aluminum-based composite material by a gravity casting method; the aluminum-based composite material is prepared from the following components in percentage by mass: 13.5 to 14.5% of Si, 6.5 to 7% of Cu, 4.5 to 5% of Ni, 1.3 to 1.5% of Mg, 0.1 to 0.4% of Fe, 0.1 to 0.4% of Mn, 0.01 to 0.04% of Zr, 0.01 to 0.04% of V, TiB21-15% of particles and the balance of Al. The aluminum-based composite piston prepared by the invention can be provided with an insert ring and a salt core inner cooling oil passage, has the characteristics of good high temperature resistance and good dimensional stability, and is suitable for various heavy diesel engines.

Description

Piston made of aluminum-based composite material for heavy-duty diesel engine and preparation method of piston
Technical Field
The invention belongs to the field of internal combustion engine parts, and particularly relates to a piston made of an aluminum-based composite material for a heavy diesel engine and a preparation method of the piston.
Background
The explosion pressure that a diesel engine piston can bear is directly related to key indexes such as the performance and the emission of the engine. In order to deal with the environmental problems caused by the exhaust emission of increasingly severe large transportation vehicles and engineering machinery, the national fifth emission standard is implemented nationwide from 7 months in 2017 in China, and the national sixth emission standard is implemented in 2020. After the national five-emission standard is implemented, the explosion pressure of the domestic heavy-duty diesel engine piston reaches more than 18MPa, and the working temperature of the combustion chamber on the top surface of the piston reaches 300-320 ℃. After the national emission standard is implemented, the explosion pressure of the piston of the heavy-duty diesel engine reaches more than 20MPa, and the working temperature of the combustion chamber on the top surface of the piston reaches 320-350 ℃.
At present, the main parts of the piston of the internal combustion engine are an aluminum alloy piston and a steel piston. The aluminum alloy piston has the advantages of small density (the mass of the piston and the inertia force of reciprocating motion can be greatly reduced), good heat conducting performance and good casting performance, and is the most widely applied piston in the current internal combustion engine. With the improvement of the requirement of the explosion pressure index of the internal combustion engine, the defect of low high-temperature strength of the aluminum alloy is shown. Under the condition that the explosion pressure is more than 18MPa, the aluminum alloy piston cannot meet the actual requirement. Therefore, researchers improve the service performance of the aluminum alloy piston for the heavy-duty diesel engine from two aspects of piston design and aluminum-based material development, and meet the requirement of high explosion pressure.
The introduction of iron inlaid ring and salt core inner cooling oil channel improves the working capacity of aluminium piston. The introduction of the iron inlaid ring improves the high-temperature resistance and the wear resistance of the piston; the design of the cold oil duct in the salt core can improve the capability of the piston for bearing high detonation pressure by reducing the temperature of the top surface of the piston and the temperature of the annular groove part. The design of the insert ring and the salt core inner cooling oil passage is widely applied to an aluminum-based piston for a heavy-duty diesel engine, for example, an aluminum alloy piston for M174 of German Muller with the design can meet the requirement of the heavy-duty diesel engine with the explosion pressure of less than 18 MPa.
In the aspect of aluminum-based materials, aluminum-based composite materials are generally a class of aluminum-based materials prepared by reinforcing an aluminum alloy matrix with ceramic as a reinforcing phase. On the basis of inheriting the advantage of low density of an aluminum matrix, the material is also endowed with the characteristics of excellent high-temperature performance and lower linear expansion coefficient. In literature search, the application of aluminum matrix composite materials to diesel engine pistons has been reported. In the beginning of the 20 th century and the 80 th century, the Nippon Toyota automobile company firstly tried the ceramic short fiber reinforced aluminum alloy composite material for preparing the piston of the diesel engine, namely, the edge of a combustion chamber of the aluminum alloy piston is locally reinforced by using alumina fiber as a prefabricated member by adopting an extrusion casting method, so that the heat resistance of the aluminum alloy piston is improved. In China, Wushengqing et al, university in southeast, have reported similar aluminum matrix composite piston technology in the application of ceramic fiber reinforced aluminum matrix composite to engine pistons (Special casting and non-ferrous alloy, 2003, Z1, pages 18-19). However, the fiber local reinforced composite piston still has the following defects: (1) the method comprises the following steps of firstly manufacturing a ceramic prefabricated part, wherein the manufacturing of the prefabricated part comprises the technological processes of ceramic fiber pretreatment, prefabricated part forming, processing, drying, sintering and the like; thereby greatly increasing the workload and the production cost for manufacturing the piston; (2) compared with a gravity casting process, the method has the advantages that the investment cost is increased by adopting an extrusion casting method, and only the piston which is simple in structure and does not have an inner cooling oil duct can be cast; (3) the poor thermal conductivity of the aluminum matrix composite region tends to cause heat concentration, thereby causing thermal stress cracking at the interface of the composite and the piston matrix. The preparation process of the ceramic short fiber reinforced aluminum alloy composite piston is improved in the research on gravity casting ceramic fiber local reinforced aluminum alloy pistons (internal combustion engine and accessories, 2-3 years 2010 and 19-22 pages) by Sunxiao et al of Bohai sea piston GmbH, Shandong Bin, and the gravity casting method is used for replacing the original extrusion casting method, so that the piston with the ring insert and the inner cooling oil duct can be prepared. Nevertheless, there is still a need to produce preforms and the problem of thermal stress cracking due to poor thermal conductivity in the region of the aluminium matrix composite remains unsolved.
Through the analysis, the ceramic reinforcing phase of the existing aluminum matrix composite piston is combined with an aluminum matrix in an additional mode to locally reinforce the piston part, so that the reinforced part material and the piston body material are inhomogeneous in thermal performance, and the hidden trouble of thermal stress cracking is caused. Meanwhile, the ceramic reinforcing phase needs to be made into a prefabricated part, so that the workload of piston manufacturing is increased, and the production cost is increased.
Under the condition of metal mold gravity casting, the piston body is made of uniform aluminum-based composite material, and the aluminum-based composite material piston which can be provided with an insert ring and a salt core inner cooling oil passage is not reported.
Disclosure of Invention
The invention provides a method for preparing an aluminum-based composite piston which is characterized in that a metal mold gravity casting technology is used, a piston body is made of uniform aluminum-based composite materials, an inlaid ring and a salt core inner cooling oil channel can be arranged in the piston, and the technical defects that the existing aluminum-based composite piston is long in technological process, and the hidden danger of thermal stress cracking at the interface between the existing aluminum-based composite piston and the piston body is high due to local reinforcement are overcome.
The purpose of the invention can be realized by the following technical scheme:
a piston made of an aluminum matrix composite material for a heavy-duty diesel engine comprises a piston body, wherein the piston body is made of the aluminum matrix composite material through a gravity casting method;
the aluminum-based composite material is prepared from the following components in percentage by mass: 13.5 to 14.5% of Si, 6.5 to 7% of Cu, 4.5 to 5% of Ni, 1.3 to 1.5% of Mg, 0.1 to 0.4% of Fe, 0.1 to 0.4% of Mn, 0.01 to 0.04% of Zr, 0.01 to 0.04% of V, TiB21-15% of particles and the balance of Al.
In a further scheme, the piston body is provided with an embedded ring and a salt core inner cooling oil duct.
Another object of the present invention is to provide a method for manufacturing the above piston, which comprises the steps of:
(1) preparation of TiB2Particle-reinforced pure aluminum composite material:
adding pure aluminum into a crucible, melting the pure aluminum into a molten state, and adding dry potassium fluoborate (KBF)4) And potassium fluotitanate (K)2TiF6) Stirring, and introducing argon into the melt; after the reaction is finished, the temperature is reduced to 760 +/-5 ℃, a refining agent is added for degassing and refining, and the surface scum is removed to obtain Al-TiB2A composite material;
(2) preparing an aluminum-based composite material melt:
adding Si, Mg, Cu, Ni, Fe, Mn, Zr and V elements into the Al-TiB prepared in the step (1) in the form of simple substance or intermediate alloy2Heating the composite material to 820-860 ℃ to completely melt the composite material, and removing floating slag on the surface of the composite material; then cooling the melt to 800-820 ℃ to obtain a uniform aluminum matrix composite melt;
(3) modification treatment of aluminum matrix composite melt: adding 0.5-1wt% of aluminum-phosphorus alterant into the aluminum-based composite material melt, and introducing argon into the melt while stirring to uniformly melt and disperse the aluminum-phosphorus alterant in the melt; then, standing the melt at 770-790 ℃ for 20-25 minutes, removing the surface scum, and then continuously preserving the temperature of the melt at 760-780 ℃;
(4) vacuum degassing and refining of aluminum matrix composite melt:
transferring the melt processed in the step (3) into a vacuum furnace, performing vacuum degassing refining for 20-25 minutes under the conditions that the temperature is 760-780 ℃ and the atmospheric pressure is-0.1 Pa, and continuously preserving heat after skimming the surface scum after refining is completed;
(5) preparing a piston:
and (4) casting the melt processed in the step (4) into a casting by using an automatic piston casting machine by adopting a gravity casting method, and then carrying out post-processing to obtain the piston.
Further scheme, potassium fluoroborate (KBF) in step (1)4) And potassium fluotitanate (K)2TiF6) The mass ratio of (1): 1.8, and drying at 210-230 ℃ for 3 hours; the stirring speed is 80-120 r/min, and the stirring time is 30 +/-5 min; and introducing argon into the melt at a flow rate of 1.2-1.8 liters/minute for 30 +/-5 minutes.
Further scheme, Al-TiB described in step (1)2TiB in composite materials2The size of the particles is 10-500nm, the shapes of the particles are mainly square, hexagonal and round, and no obvious sharp corner exists.
Further, in the step (3), the stirring speed is 60-80 r/min, and the time is 5-10 min; the flow rate of the introduced argon is 0.5-0.8 liter/minute, and the time is 5-10 minutes.
In a further scheme, in the step (5), before casting, the salt core and the insert ring are placed.
Further, the post-treatment in the step (5) is that the piston casting is taken out and naturally cooled, and a pouring gate and a dead head part are machined and removed; heating the piston casting to 510 +/-5 ℃, preserving heat for 3 hours, and cooling in warm water at 50-60 ℃; then preserving heat for 6-8 hours at the temperature of 240 +/-5 ℃ for aging treatment; and finally machining and surface treating.
In the prior art, solid chlorine salt or hexachloroethane is mainly used as a refining agent in the refining treatment of the piston aluminum alloy, a large amount of toxic gas is generated in the refining process, and the environment is greatly polluted. Meanwhile, in the refining process, a very violent slagging process is usually adopted, which can cause TiB in the composite material melt2Particle loss of the reinforcing phase. Therefore, the invention refines the composite material melt by adopting a vacuum degassing method, and the vacuum degassing method uses a vacuum furnace and does not use a refining agent, so that TiB is not caused2Particle loss of the reinforcing phase.
Due to TiB2The melting point of the titanium-based alloy reaches 2980 ℃, so that TiB in the aluminum-based composite material is generated in the preparation and use processes of the piston2The particles always keep in TiB2The particles enhance the appearance and size characteristics of the pure aluminum composite material, thereby generating pinning and other interaction effects on aluminum alloy dislocation and achieving the purposes of blocking the deformation of an alloy matrix and improving the high-temperature mechanical property of the alloy matrix.
The piston body is made of an aluminum-based composite material through a gravity casting method, wherein the aluminum-based composite material contains TiB2Nanoparticles, which have the following benefits: first, TiB2As a ceramic phase, the melting point of the TiB ceramic phase is as high as 2980 ℃, and the TiB ceramic phase has a temperature of 200 ℃ and 400 ℃ in the main working temperature range of the piston2The morphology and size of the particles do not change. Secondly, the matrix deformation of the aluminum alloy is mainly achieved by means of dislocation motion, while TiB2The particles have a nano scale, have a scale similar to that of dislocation, and can generate pinning and other interaction effects on the dislocation, so that the deformation of an alloy matrix is hindered, and the high-temperature mechanical property of the alloy matrix is improved. Due to the fact thatHerein, TiB2The particles are beneficial to improving the mechanical property of the piston made of the aluminum-based composite material under the high-temperature condition, and the mechanical property is higher than the high-temperature tensile strength of the German Muller M174 aluminum alloy piston.
In addition, since TiB2The average linear expansion coefficient of the particles in the range of 20-400 ℃ is-7.8 multiplied by 10-6 ℃-1Far below the average linear expansion coefficient (22.5 multiplied by 10) of the aluminum alloy piston-6 ℃-1). Therefore, the piston made of the aluminum matrix composite material has a smaller thermal expansion coefficient in the working temperature range of the piston so as to keep the dimensional stability and the air leakage prevention performance of the piston.
The aluminum-based composite material is prepared from Si, Cu, Ni, Mg, Fe, Mn, Zr, V and TiB2The particles and Al improve the high temperature resistance and the processing performance of the material, and compared with the existing aluminum-based composite material (CN 201410118155.5) which is prepared by silicon, copper, nickel, titanium bromide, magnesium, boron oxide, titanium, chromium and aluminum by a centrifugal casting method, the material has higher temperature resistance, high-temperature tensile strength and lower average linear expansion coefficient.
In addition, Si, Mg, Cu, Ni, Fe, Mn, Zr and V are added into TiB together in the preparation process2The particle reinforced pure aluminum composite material is mixed and melted, which is beneficial to accurately controlling the content of alloy elements. At the same time, the solute atoms in the melt and TiB are promoted2Uniform dispersion of the particles. In the later modification process, solute atoms, particularly Si atoms are uniformly dispersed, so that the aluminum and the phosphorus can be promoted to better exert modification effect. Finally, the composite material melt is refined by using a vacuum furnace without a refining agent, so that TiB is not caused2Particle loss of the reinforcing phase.
In conclusion, the piston made of the aluminum matrix composite material has better high-temperature performance and dimensional stability, and can meet the use requirements of heavy-duty diesel engines.
Drawings
FIG. 1 shows TiB in the aluminum matrix composite of the present invention2The morphology and the size of the particles,
FIG. 2 shows an aluminum-based composite material of the present inventionTiB in the stock2The size distribution profile of the particles is such that,
FIG. 3 shows TiB in the aluminum matrix composite of the present invention2The particles are pinned at the dislocations and,
FIG. 4 shows TiB in a piston according to the invention2The relationship between the particle content and the 350 ℃ high-temperature tensile strength of the combustion chamber at the top of the piston,
FIG. 5 shows TiB in a piston according to the invention2The relationship between the particle content and the mean linear expansion coefficient of the combustion chamber at the top of the piston in the range of 20-400 ℃.
Detailed Description
The present invention will be described in detail with reference to specific examples.
Example 1
The piston made of the aluminum matrix composite material for the heavy-duty diesel engine comprises a piston body, wherein the piston body is made of the aluminum matrix composite material by a gravity casting method; and the piston body is provided with an embedded ring and a salt core inner cooling oil duct.
The aluminum-based composite material in the embodiment is prepared from the following components in percentage by mass: 13.5% of Si, 6.6% of Cu, 4.7% of Ni, 1.3% of Mg, 0.1% of Fe, 0.2% of Mn, 0.01% of Zr, 0.01% of V, and TiB21% of particles and the balance of Al.
The preparation method comprises the following steps:
（A）TiB2preparing a master batch of the particle reinforced pure aluminum composite material:
(1) preparing a dry crucible, adding weighed pure aluminum into the crucible to melt an aluminum ingot, and heating to 925 ℃ to melt the aluminum ingot;
(2) weighing the inorganic salt potassium fluoborate (KBF)4) And potassium fluotitanate (K)2TiF6) Uniformly mixing the components according to the mass ratio of 1:1.8, and drying the mixture for 3 hours at 210 ℃ for later use;
(3) after the pure aluminum is completely melted, adding the dried inorganic salt for later use into the aluminum melt, mechanically stirring (the stirring speed is 90 revolutions per minute, and the time lasts for 30 +/-5 minutes), and simultaneously introducing argon (the gas flow rate is 1.3 liters per minute, and the time lasts for 30 +/-5 minutes) into the melt so that the reaction is smoothly carried out;
(4) after the reaction is finished, cooling the melt to 760 +/-5 ℃, adding a refining agent for degassing and refining, removing surface scum, pouring the melt into a long-strip metal mold to obtain Al-TiB2The composite material of (1).
Wherein, TiB2The particle shapes are mainly square, hexagonal and round, and have no sharp corners (as shown in figure 1). TiB2The size of the particles is in the range of 10-500nm (as shown in FIGS. 1 and 2).
(B) Preparing an aluminum-based composite material melt: preparing a dry crucible, weighing the Al-TiB2The composite material is put into the molten alloy, Si, Mg, Cu, Ni, Fe, Mn, Zr and V elements are added into the molten alloy in a simple substance or intermediate alloy mode, the temperature is raised to 820 +/-5 ℃ to be completely molten, and then surface scum is removed; and then cooling the melt to obtain a uniform melt at 800 ℃.
(C) Modification treatment of aluminum matrix composite melt: mainly uses a phosphorus-containing refiner to refine primary silicon. The method comprises the following steps: adding 0.5wt% of aluminum-phosphorus alterant into the melt at 800 ℃, mechanically stirring the melt after adding the alterant (the stirring speed is 60 revolutions per minute, the time lasts for 5 minutes), and simultaneously introducing argon gas into the melt (the gas flow rate is 0.5 liters per minute, the time lasts for 5 minutes) so that the aluminum-phosphorus alterant is uniformly melted and dispersed in the melt. Then, the mechanical stirring and the argon stirring were removed, and the melt was kept at 770 ℃ for 20 minutes to promote the exertion of the deterioration effect. After the melt is deteriorated, removing the floating slag on the surface; the melt was then held at 760 ℃.
(D) Vacuum degassing and refining of aluminum matrix composite melt: transferring the melt into a vacuum furnace, keeping the temperature at 760 ℃ and the atmospheric pressure at-0.1 Pa, performing vacuum degassing refining for 20 minutes, removing surface scum after refining is completed, and keeping the temperature of the melt at 770 ℃. At this point, the melt processing is complete and the casting of the piston can begin.
(E) Preparing an aluminum-based composite material piston casting and carrying out heat treatment: an automatic piston casting machine is used for manually or automatically placing the salt core and the inlaid ring, and a metal lower core-pulling gravity casting process is adopted. The thick part of the top of the piston faces upwards, and the core is drawn downwards. The casting pouring temperature is 770 +/-5 ℃,
and taking out the casting, naturally cooling, and then machining to remove the sprue and the riser part. And finally, heating the piston casting to 510 ℃, preserving heat for 3 hours, cooling the piston casting in warm water at 50-60 ℃, and then carrying out aging treatment at 245 ℃ for preserving heat for 6 hours.
(F) Machining and surface treatment of the aluminum-based composite material piston casting: and (3) machining and surface treating the piston casting after heat treatment to obtain an aluminum-based composite material piston finished product, which can meet the use requirement of a heavy-duty diesel engine with the explosion pressure of 19 MPa.
In the aluminum matrix composite material prepared by the embodiment, TiB2 particles generate obvious pinning effect on dislocation, so that the effect of reinforcing a matrix is achieved, and the purpose of preventing the deformation of the alloy matrix and improving the high-temperature mechanical property of the alloy matrix is achieved, as shown in FIG. 3.
Example 2
The aluminum-based composite material in the embodiment is prepared from the following components in percentage by mass: 14% of Si, 6.7% of Cu, 4.9% of Ni, 1.4% of Mg, 0.25% of Fe, 0.15% of Mn, 0.02% of Zr, 0.02% of V and TiB 26% of particles and the balance of Al.
The preparation method comprises the following steps:
（A）TiB2preparation of master batch of particle reinforced pure aluminum composite material
(1) Preparing a dry crucible, adding weighed pure aluminum into the crucible to melt an aluminum ingot, and heating to 925 ℃ to melt the aluminum ingot;
(2) weighing the inorganic salt potassium fluoborate (KBF)4) And potassium fluotitanate (K)2TiF6) Uniformly mixing the components according to the mass ratio of 1:1.8, and drying the mixture for 3 hours at 210 ℃ for later use;
(3) after the pure aluminum is completely melted, adding the dried inorganic salt for later use into the aluminum melt, mechanically stirring (the stirring speed is 100 revolutions per minute, the time lasts for 30 minutes), and simultaneously introducing argon (the gas flow rate is 1.5 liters per minute, the time lasts for 30 minutes) into the melt so that the reaction is smoothly carried out;
(4) when the reaction is completed, the melt is cooled to 760 ℃, and the essence is addedDegassing and refining the refining agent, removing the surface scum, pouring the melt into a long-strip metal mold to obtain Al-TiB2The composite material of (1).
Wherein, TiB2The particle shapes are mainly square, hexagonal and round, and have no sharp corners (as shown in figure 1). TiB2The size of the particles ranged from 10 to 500nm (as shown in FIGS. 1 and 2).
(B) Preparing an aluminum-based composite material melt: preparing a dry crucible, weighing the Al-TiB2The composite material is put into the molten alloy, Si, Mg, Cu, Ni, Fe, Mn, Zr and V elements are added into the molten alloy in a simple substance or intermediate alloy mode, the temperature is raised to 840 ℃ to be completely melted, and then surface scum is removed; then the melt is cooled to 810 ℃ to obtain a uniform melt.
(C) Modification treatment of aluminum matrix composite melt: mainly uses a phosphorus-containing refiner to refine primary silicon. The method comprises the following steps: adding 0.75wt% of aluminum-phosphorus alterant into a melt at 810 ℃, mechanically stirring the melt after adding the alterant (the stirring speed is 70 r/min, the time lasts for 8 min), and simultaneously introducing argon gas into the melt (the gas flow rate is 0.6 l/min, the time lasts for 8 min) to ensure that the aluminum-phosphorus alterant is uniformly melted and dispersed in the melt. Then, the mechanical stirring and the argon stirring were removed, and the melt was kept at 780 ℃ for 23 minutes to promote the exertion of the deterioration effect. After the melt is deteriorated, removing the floating slag on the surface; the melt was then held at 770 ℃.
(D) Vacuum degassing and refining of aluminum matrix composite melt: transferring the melt into a vacuum furnace, keeping the temperature at 770 ℃ and the atmospheric pressure at-0.1 Pa, performing vacuum degassing refining for 23 minutes, removing surface scum after refining is finished, and keeping the temperature of the melt at 785 ℃. At this point, the melt processing is complete and the casting of the piston can begin.
(E) Preparing an aluminum-based composite material piston casting and carrying out heat treatment: an automatic piston casting machine is used for manually or automatically placing the salt core and the inlaid ring, and a metal lower core-pulling gravity casting process is adopted. The thick part of the top of the piston faces upwards, and the core is drawn downwards. The casting pouring temperature is 785 +/-5 ℃,
and taking out the casting, naturally cooling, and then machining to remove the sprue and the riser part. And finally, heating the piston casting to 510 ℃, preserving heat for 3 hours, cooling the piston casting in warm water at 50-60 ℃, and then carrying out aging treatment at 245 ℃ for preserving heat for 6 hours.
(F) Machining and surface treatment of the aluminum-based composite material piston casting: and (3) machining and surface treating the piston casting after heat treatment to obtain the aluminum-based composite material piston finished product, which can meet the use requirement of a heavy-duty diesel engine with the explosion pressure of 21 MPa.
Example 3
The aluminum-based composite material in the embodiment is prepared from the following components in percentage by mass: 14.5% of Si, 7% of Cu, 4.5% of Ni, 1.5% of Mg, 0.1% of Fe, 0.2% of Mn, 0.04% of Zr, 0.04% of V, and TiB 212% of particles and the balance of Al.
The preparation method comprises the following steps:
（A）TiB2preparing a master batch of the particle reinforced pure aluminum composite material:
(1) preparing a dry crucible, adding weighed pure aluminum into the crucible to melt an aluminum ingot, and heating to 925 ℃ to melt the aluminum ingot;
(2) weighing the inorganic salt potassium fluoborate (KBF)4) And potassium fluotitanate (K)2TiF6) Uniformly mixing the components according to the mass ratio of 1:1.8, and drying the mixture for 3 hours at 210 ℃ for later use;
(3) after the pure aluminum is completely melted, adding the dried inorganic salt for later use into the aluminum melt, mechanically stirring (the stirring speed is 100 revolutions per minute, the time lasts for 30 minutes), and simultaneously introducing argon (the gas flow rate is 1.5 liters per minute, the time lasts for 30 minutes) into the melt so that the reaction is smoothly carried out;
(4) after the reaction is finished, cooling the melt to 760 ℃, adding a refining agent for degassing and refining, removing surface scum, pouring the melt into a long-strip metal mold to obtain Al-TiB2The composite material of (1).
Wherein, TiB2The particle shapes are mainly square, hexagonal and round, and have no sharp corners (as shown in figure 1). TiB2The size of the particles is in the range of 10-500nm (As shown in fig. 1 and 2).
(B) Preparing an aluminum-based composite material melt: preparing a dry crucible, weighing the Al-TiB2The composite material is put into the molten alloy, Si, Mg, Cu, Ni, Fe, Mn, Zr and V elements are added into the molten alloy in a simple substance or intermediate alloy mode, the temperature is raised to 860 ℃ to be completely melted, and then surface scum is removed; then the melt is cooled to 820 ℃ to obtain a uniform melt.
(C) Modification treatment of aluminum matrix composite melt: mainly uses a phosphorus-containing refiner to refine primary silicon. The method comprises the following steps: adding 1wt% of aluminum-phosphorus alterant into 820 ℃ melt, mechanically stirring the melt after adding the alterant (the stirring speed is 80 r/min, the time lasts 10 min), and simultaneously introducing argon (the gas flow rate is 0.7 l/min, the time lasts 10 min) into the melt so that the aluminum-phosphorus alterant is uniformly melted and dispersed in the melt. Then, the mechanical stirring and the argon stirring were removed, and the melt was kept at 790 ℃ for 25 minutes to promote the exertion of the deterioration effect. After the melt is deteriorated, removing the floating slag on the surface; the melt was then held at 780 ℃.
(D) Vacuum degassing and refining of aluminum matrix composite melt: transferring the melt into a vacuum furnace, keeping the temperature at 780 ℃ and the atmospheric pressure at-0.1 Pa, performing vacuum degassing refining for 25 minutes, removing surface scum after refining is finished, and keeping the temperature of the melt at 800 ℃. At this point, the melt processing is complete and the casting of the piston can begin.
(E) Preparing an aluminum-based composite material piston casting and carrying out heat treatment: an automatic piston casting machine is used for manually or automatically placing the salt core and the inlaid ring, and a metal lower core-pulling gravity casting process is adopted. The thick part of the top of the piston faces upwards, and the core is drawn downwards. The casting pouring temperature is 800 +/-5 ℃,
and taking out the casting, naturally cooling, and then machining to remove the sprue and the riser part. And finally, heating the piston casting to 510 ℃, preserving heat for 3 hours, cooling the piston casting in warm water at 50-60 ℃, and then carrying out aging treatment at 245 ℃ for preserving heat for 6 hours.
(F) Machining and surface treatment of the aluminum-based composite material piston casting: and (3) machining and surface treating the piston casting after heat treatment to obtain the aluminum-based composite material piston finished product, which can meet the use requirement of a heavy-duty diesel engine with the explosion pressure of 23 MPa.
Example 4
The piston cast by the aluminum-based composite material prepared by the invention is compared with the M174 piston which is common in the market at present. FIG. 4 shows the relationship between the TiB2 particle content in the piston of the present invention and the 350 deg.C tensile strength of the combustion chamber at the top of the piston. With the increase of the content of TiB2 particles, the tensile strength of the piston at the top combustion chamber at the high temperature of 350 ℃ is gradually improved and is higher than that of the M174 piston which is common in the market at the same position, so that better high-temperature resistance is shown.
Fig. 5 shows the relationship between the content of TiB2 particles in the piston according to the invention and the mean linear expansion coefficient in the piston crown combustion chamber in the range of 20-400 c. As can be seen from the figure, with the increase of the content of TiB2 particles, the average linear expansion coefficient of the combustion chamber at the top of the piston in the range of 20-400 ℃ is gradually reduced and is higher than that of the M174 piston which is common in the market at the same position, thereby showing better dimensional stability.
The embodiments described above are intended to facilitate one of ordinary skill in the art in understanding and using the present invention. It will be readily apparent to those skilled in the art that various modifications can be made to the embodiments and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the embodiments described herein, and those skilled in the art should make modifications and alterations without departing from the scope of the present invention.

Claims (1)

1. A preparation method of a piston made of an aluminum matrix composite material for a heavy-duty diesel engine is characterized by comprising the following steps: the method comprises the following steps:
(1) preparation of TiB2Particle-reinforced pure aluminum composite material:
adding pure aluminum into a crucible to be melted into a molten state, and then adding dried potassium fluoborate and potassium fluotitanate into the crucibleStirring, and introducing argon into the melt; after the reaction is finished, the temperature is reduced to 760 ℃, a refining agent is added for degassing and refining, and the surface scum is removed to obtain Al-TiB2A composite material;
(2) preparing an aluminum-based composite material melt:
adding Si, Mg, Cu, Ni, Fe, Mn, Zr and V elements into the Al-TiB prepared in the step (1) in the form of simple substance or intermediate alloy2In the composite material, after the composite material is heated to 860 ℃ to be completely melted, the scum on the surface is removed; then cooling the melt to 820 ℃ to obtain a uniform aluminum matrix composite melt;
(3) modification treatment of aluminum matrix composite melt:
adding 1wt% of aluminum-phosphorus alterant into the aluminum-based composite material melt, and introducing argon into the melt while stirring to uniformly melt and disperse the aluminum-phosphorus alterant in the melt; then, standing the melt at 790 ℃ for 25 minutes, removing the surface scum, and keeping the temperature of the melt at 780 ℃;
(4) vacuum degassing and refining of aluminum matrix composite melt:
transferring the melt processed in the step (3) into a vacuum furnace, performing vacuum degassing refining for 25 minutes under the conditions that the temperature is 780 ℃ and the atmospheric pressure is-0.1 Pa, and continuously preserving heat after skimming the surface scum after the refining is finished;
(5) preparing a piston:
casting the melt processed in the step (4) into a casting by adopting a gravity casting method by using an automatic piston casting machine, and then carrying out post-processing to obtain a piston;
the piston comprises a piston body, and the piston body is made of an aluminum-based composite material by a gravity casting method; the piston body is provided with an embedded ring and a salt core inner cooling oil duct;
the aluminum-based composite material is prepared from the following components in percentage by mass: 14.5% of Si, 7% of Cu, 4.5% of Ni, 1.5% of Mg, 0.1% of Fe, 0.2% of Mn, 0.04% of Zr, 0.04% of V, and TiB212% of particles and the balance of Al;
in the step (1), the mass ratio of the potassium fluoborate to the potassium fluotitanate is 1:1.8, and drying at 210 ℃ for 3 hours; the stirring speed is 100 revolutions per minute, and the stirring time is 30 minutes; introducing argon into the melt at a flow rate of 1.5 liters/minute for 30 minutes;
the Al-TiB2TiB in composite materials2The size of the particles is 10-500nm, the particle shapes are mainly square, hexagonal and round, and no obvious sharp corner exists;
the stirring speed in the step (3) is 80 revolutions per minute and the time is 10 minutes; the flow rate of the introduced argon is 0.7 liter/minute, and the time is 10 minutes;
placing a salt core and an inlaid ring before casting in the step (5); the post-treatment is that the piston casting is taken out and naturally cooled, and a pouring gate and a dead head part are machined and removed; heating the piston casting to 510 ℃, preserving heat for 3 hours, and cooling in warm water at 50-60 ℃; then preserving heat for 6 hours at the temperature of 245 ℃; and finally, machining and surface treatment are carried out to obtain the finished product of the aluminum-based composite piston, so that the use requirement of a heavy-duty diesel engine with the explosion pressure of 23MPa is met.
CN201810606664.0A 2018-06-12 2018-06-12 Piston made of aluminum-based composite material for heavy-duty diesel engine and preparation method of piston Active CN108796316B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810606664.0A CN108796316B (en) 2018-06-12 2018-06-12 Piston made of aluminum-based composite material for heavy-duty diesel engine and preparation method of piston

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810606664.0A CN108796316B (en) 2018-06-12 2018-06-12 Piston made of aluminum-based composite material for heavy-duty diesel engine and preparation method of piston

Publications (2)

Publication Number Publication Date
CN108796316A CN108796316A (en) 2018-11-13
CN108796316B true CN108796316B (en) 2020-11-20

Family

ID=64085358

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810606664.0A Active CN108796316B (en) 2018-06-12 2018-06-12 Piston made of aluminum-based composite material for heavy-duty diesel engine and preparation method of piston

Country Status (1)

Country Link
CN (1) CN108796316B (en)

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1257299C (en) * 2002-12-11 2006-05-24 山东大学 Aluminium-based composite material for piston and preparation method thereof
US7666353B2 (en) * 2003-05-02 2010-02-23 Brunswick Corp Aluminum-silicon alloy having reduced microporosity
US20080029186A1 (en) * 2006-02-14 2008-02-07 Stanley Abkowitz Homogeneous titanium tungsten alloys produced by powder metal technology
CN101463440B (en) * 2009-01-15 2010-06-09 山东大学 Aluminum based composite material for piston and preparation thereof
CN104264001B (en) * 2014-09-16 2016-08-17 广东新劲刚新材料科技股份有限公司 In-situ synthesized particle reinforced aluminum matrix composite material and preparation method thereof
CN104907534B (en) * 2015-05-11 2017-01-18 中国兵器科学研究院宁波分院 Counter-pressure casting mold and method for aluminum alloy piston workblank
CN104911416B (en) * 2015-06-19 2016-09-07 华中科技大学 A kind of in-situ particle hybrid reinforced aluminum-matrix composite material and preparation method thereof
CN105483451A (en) * 2015-12-09 2016-04-13 上海交通大学 Nano ceramic particle reinforcing aluminum alloy for piston and manufacturing method of nano ceramic particle reinforcing aluminum alloy
CN105908024A (en) * 2016-06-21 2016-08-31 上海交通大学 High-temperature-resistant nano ceramic particle reinforced cocrystallized Al-Si alloy and casting method thereof
CN107254612A (en) * 2017-06-09 2017-10-17 山东滨州渤海活塞股份有限公司 A kind of confusion enhancing novel wear resistant aluminum matrix composite and preparation method thereof

Also Published As

Publication number Publication date
CN108796316A (en) 2018-11-13

Similar Documents

Publication Publication Date Title
CN103042195B (en) Extrusion casting manufacture method of piston with reinforced pseudo-alloy circular groove
CN102764957B (en) Method for manufacturing hypereutectic aluminum-silicon alloy engine cylinder sleeve
CN111690849A (en) Refining method of iron-rich phase in Al-Si series die-casting aluminum alloy and alloy
CN110724861B (en) High-performance aluminum alloy engine cylinder cover and casting method thereof
CN103846409B (en) A kind of preparation method of the fibre reinforced composites piston peculiar to vessel with cooling oil chamber
CN101693972B (en) Method for preparing heat resistant rare earth-magnesium alloy engine pistons through squeezing and casting
CN110983120A (en) 300 MPa-grade high-strength plastic non-heat-treatment self-strengthening die-casting aluminum alloy and manufacturing method thereof
CN103243236B (en) High-toughness wear-resistant zinc alloy containing fine crystalline grains and preparation process for same
CN108048703B (en) High-strength wear-resistant die-casting aluminum alloy and die-casting method thereof
CN106636787A (en) High-toughness die-casting aluminum alloy and preparation method thereof
CN114411031B (en) Micron titanium particle reinforced magnesium rare earth based composite material
CN110042281B (en) Cast aluminum alloy and preparation method thereof
CN101446243B (en) Piston made of Al/Si-Mg*Si composite material and preparation method thereof
CN1904084A (en) Production method of high strength synthetic cast iron electric machine main shaft disk
CN117026003B (en) Aluminum-based composite material stirring casting preparation method based on composite modification refinement
CN107779696B (en) A kind of multi-element alloyed aluminum alloy materials, cylinder jacket and preparation method thereof
CN108796316B (en) Piston made of aluminum-based composite material for heavy-duty diesel engine and preparation method of piston
CN105950929B (en) Hypereutectic Al Si alloys and magnesium alloy hybrid engine cylinder body and its casting method
CN111074109B (en) Biphase ceramic particle reinforced aluminum-based composite material, brake drum and preparation method thereof
CN111545726A (en) Directional Ti3SiC2Reinforced magnesium-based composite material cylinder block and preparation method thereof
CN1122726C (en) Aluminium-silicon alloy without, solidification shrinking and its casting technology
CN114959378A (en) Preparation method of aluminum-silicon alloy and casting of aluminum-silicon alloy
CN100557054C (en) Contain creep resistance Dow metal of Si and C and preparation method thereof
CN113231791A (en) Magnesium-based composite material cylinder sleeve for motorcycle engine and preparation method thereof
CN115652159B (en) High-strength and high-toughness die-casting magnesium alloy and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant