JPH02236242A - Manufacture of aluminum alloy material - Google Patents

Abstract

PURPOSE:To manufacture the Al alloy material having good ductility by sealing Al ally powder contg. specified amounts of Si and Fe, subjecting the powder to specified vacuum deaeration and molding and subjecting the formed part to specified solution heat treatment, quenching and natural aging. CONSTITUTION:Al alloy powder contg., by weight, 15 to 35% Si and 0.3 to 9% Fe as main alloy components is sealed and is subjected to vacuum deaeration treatment at 430 to 520 deg.C for 5 to 100hr. Next, the sealed can field with the Al alloy powder is subjected to forming such as extruding. The formed part obtd. by this method are subjected to solution heat treatment at 460 to 500 deg.C usually for about 30min to 24hr. After that, the formed part are quenched by water or, for the ones having complicated shape, by using hot water. Then, the treated part are subjected to natural aging and/or artificial aging treatment at <=185 deg.C for the time shorter than that required for obtaining maximum hardness. In this way, the Al-Si-Fe series alloy material having improved elongation percentage and free from the generation of cracking, chipping, etc., in the process of working can be obtd.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to an improvement in the manufacturing method of an aluminum alloy material,
In particular, it relates to a method for improving the ductility of materials obtained from Al-Si-Fe powder alloys.

(Background Art) Cylinder blocks, cylinder liners and pistons of internal combustion engines, as well as compressor vane materials, etc., require characteristics such as excellent wear resistance, low thermal expansion characteristics, high-temperature strength, and heat resistance. Therefore, in recent years, in order to manufacture these materials from lightweight aluminum (A1) alloys, aluminum containing a large amount of silicon (Si) as an alloy component has been developed.
An e-Si powder alloy has been proposed, and the applicant of the present application has previously disclosed an Aff-St-Fe powder alloy (see Japanese Patent Publication No. 16459/1983) that satisfies such characteristics.

By the way, in such aluminum alloys containing a large amount of St, Si precipitates during solidification, so
Since it is difficult to cast, the molten alloy is usually rapidly cooled and solidified by a spraying method to obtain powder or flake alloy powder, and then the alloy material in the desired shape is formed from this alloy powder. things are being done. More specifically, since it is difficult to perform a molding operation directly from the obtained powder, the alloy powder is first classified, pre-compressed if necessary, and sealed in a designated can. The contents of the can are subjected to vacuum deaeration treatment, and then the can contents subjected to such deaeration treatment are subjected to a forming operation such as extrusion molding or hot pressing, and further molding processing such as forging. The alloy material is then processed to form the desired shape.

Therefore, the Af-Si-Fe alloy material obtained by molding according to the above-mentioned normal molding operation is usually provided as a material for connecting rods etc. after being subjected to heat treatment to increase its strength. However, while it shows the expected good strength, its elongation rate is low at around 0.3 to 0.7%. There was an inconvenience that the parts were missing.

(Problem to be solved) The present invention has been made against the background of the above circumstances, and the problem to be solved is 8! -An object of the present invention is to improve the ductility of a Si-Fe alloy material.

(Solution Means) Therefore, in the present invention, in order to solve the above problems,
After sealing the aluminum alloy powder containing 15 to 35% by weight of Si and 0.3 to 9% by weight of Fe as main alloy components, vacuum desorption was performed at a temperature of 430 to 520°C for 5 to 100 hours. The molded product was subjected to air treatment, then molded, and the resulting molded product was subjected to solution treatment at a temperature of 460°C to 500°C, followed by water or hot water quenching, and natural aging. Yes, or also
After sealing a similar aluminum alloy powder, 430~5
After carrying out vacuum degassing treatment for 5 to 100 hours at a temperature of 20°C, then molding, and solution treatment of the obtained molded article at a temperature of 460°C to 500'C, Water or hot water quenching is performed, and artificial aging treatment is performed at a temperature of 185° C. or less for a time shorter than that required to obtain maximum hardness.

(Function/Effect) In short, according to the method for producing an aluminum alloy material according to the present invention as described above, aluminum alloy powder is molded after being subjected to vacuum degassing treatment within a specific range, and furthermore, the aluminum alloy powder after the molding is completed is By subjecting the material to heat treatment under specific conditions, it was possible to advantageously improve the ductility of the Af-Si-Fe alloy material for the first time. By applying this method, it is possible to effectively prevent cracks and chips from occurring in the material when manufacturing various parts and components such as connecting rods, and as a result, a significant improvement in workability can be achieved. It has become.

On the other hand, the properties such as good wear resistance, low thermal expansion, high temperature strength, and heat resistance obtained from the alloy composition containing Si and Fe as the main alloy components are not impaired in any way by the manufacturing method according to the present invention. Therefore, the aluminum alloy material of the present invention can be used in various parts that require each of these performances, and these parts, as well as the machines and engines in which they are used, can be made lighter and faster. can be advantageously achieved.

Furthermore, the manufacturing method according to the present invention has the advantage that the above effects can be obtained without adding any new steps, in other words, without any new equipment investment.

(Specific structure) By the way, the aluminum alloy material in the present invention has silicon (St) and iron (Fe) as main alloy components, each of which is contained in an amount of 15 to 35% (by weight, the same applies hereinafter), It is contained in a proportion of 0.3 to 9%.

Among these main alloy components, the addition of St significantly improves the wear resistance and seizure resistance of the target alloy material, and also lowers the coefficient of thermal expansion, and the amount of St added is less than 15%. However, on the other hand,
When it exceeds 35%, the machinability of the alloy material is reduced, the life of the cutting tool is adversely affected, and the surface roughness of the cutting surface becomes rough. Furthermore, Fe has the effect of improving the heat resistance and high-temperature strength of the alloy material, and an amount of less than 0.3% can exhibit a sufficient effect, but an amount of more than 9% If it is added, the effect will be saturated and the ductility of the alloy material will be significantly reduced.

In addition to these alloy components, depending on the performance required for the target alloy material, copper (Cu), magnesium (Mg), manganese (Mn), nickel (Ni), etc.
It goes without saying that it is possible to contain it as appropriate. In addition, Cu coexists with Mg and has the effect of imparting age hardenability to the alloy material, improving room temperature strength and wear resistance, and further improves the high temperature strength of the alloy material by solid solution hardening. It has the characteristics of 0. 5-10
%. Moreover, Mg is C
Together with u, it imparts age hardenability to the alloy material, and also provides room temperature strength,
It improves wear resistance, and like Cu, it has the effect of improving the high temperature strength of alloy materials by being solid solution hardened. It will be contained in a proportion of 3 to 6%. Furthermore, Mn improves the heat resistance of the alloy material and increases its high-temperature strength. It is contained in a proportion of 3 to 4%. Furthermore, Ni cooperates with Fe, which is the main alloy component, to improve the heat resistance of the alloy material and to increase the high-temperature strength.
It will be contained in a proportion of 3 to 9%.

When forming aluminum alloy powder from a molten alloy containing such alloy components, it is desirable to rapidly solidify the molten alloy as in the past. This is because the faster the cooling rate, the more the precipitation of Si can be suppressed, the size of the Si particles in the final product becomes finer, and the machinability and wear resistance can be improved. As for the rapid cooling rate, a cooling rate of 100° C./second or more is preferably employed, and specifically, an atomization method, a rapid solidification method (sprunt cooling), etc. are applied. In particular, in the former case, aluminum alloy powder with an average particle size of 200 μm or less can be obtained by atomizing the molten alloy.

In the method for producing an aluminum alloy material according to the present invention, first, the aluminum alloy powder thus obtained (including those in flake form) is classified into sealed cans or Through the process of classification and preliminary compression and sealing, the sealed can is filled with a predetermined aluminum alloy powder, and the sealed can is subjected to a specific range of degassing treatment.

That is, the alloy powder-filled enclosure is held at a temperature of 430 to 520° C. for 5 to 1000 hours while being evacuated. This step constitutes one of the requirements for the method of manufacturing an aluminum alloy material according to the present invention,
Even if only this step is introduced into conventional manufacturing methods, it is possible to improve the ductility of the resulting alloy material to a certain degree. In addition, in this degassing treatment, if the temperature is lower than 430°C, the elongation of the alloy material will be insufficient, and if the temperature is lower than 430°C,
When the elongation of the alloy material exceeds the
The strength will also be reduced. In addition, if the degassing treatment time is shorter than 5 hours, the elongation of the alloy material will be insufficient, and 1
When the time is longer than 00 hours, the effect of improving the elongation of the alloy material comes to be saturated. More specific temperature and time will be determined as appropriate depending on the alloy composition and powder shape of the aluminum alloy, the degree of preliminary compression, etc. In addition, the degree of vacuum for degassing will be determined appropriately.
It is generally 10 Torr or less, preferably 1 Torr or less.

Next, various molding operations such as extrusion molding and hot pressing are performed on the degassed aluminum alloy powder-filled can as usual.

For example, in the case of extrusion molding, the degassing can is heated to a temperature of 400 to 480°C and hot extrusion is performed at an extrusion ratio of 4 or more to obtain an aluminum alloy material in the desired shape. The extrudate can be further processed, such as forging, if necessary.

In this way, it is possible to obtain an alloy material (material) in the desired shape, but if the manufacturing method of the present invention is followed,
Such an alloy material is successively subjected to a series of heat treatment operations such as solution treatment, first quenching, and temporary treatment under specific conditions, as described below.

In other words, like the degassing process described above, this heat treatment process is one of the requirements of the present invention, and even if only this process is introduced into the conventional manufacturing method, the resulting alloy material will have a certain level of It is capable of imparting the effect of improving ductility.

The specific method is to first heat the alloy material, which has been subjected to extrusion molding, hot pressing, etc., at 460°C to
The alloy material is maintained at a temperature of 500° C. to undergo solution treatment. The holding time is set to be enough time for the alloy components to be sufficiently dissolved in the solid solution, and is generally 30
It is selected within the range of minutes to 24 hours, but the more specific solution treatment temperature and holding time are determined as appropriate depending on the alloy composition, the shape and cross-sectional area of the alloy material, etc. By the way. Note that if the solution treatment temperature is less than 460°C, the alloy material cannot have sufficient strength, while if it exceeds 500°C, the elongation of the alloy material will decrease.

Then, after the solution treatment, quenching is performed using water or hot water as a medium. At that time, in order to give the alloy material sufficient strength, it is best to cool it as quickly as possible.
In cases where the alloy material has a complicated cross-sectional shape, it is also effective to use hot water to suppress the generation of residual stress. Further, as a hardening method, it goes without saying that any known method can be used, such as putting the alloy material into a medium or spraying the medium onto the alloy material. In short, the quenching rate is appropriately determined depending on the alloy composition, shape, etc. of the alloy material, and the medium temperature and quenching method may be determined as necessary.

Furthermore, the alloy material that has been subjected to such solution treatment and quenching is subsequently subjected to natural aging treatment or artificial aging treatment (hereinafter referred to as A series of heat treatments are completed by performing sub-aging treatment. Furthermore, if the sub-aging treatment temperature exceeds 185°C, the alloy material will reach its maximum hardness during the temperature rise or in a very short time after the temperature rise, and then it will begin to soften, which will affect the strength of the alloy material, especially fatigue. In addition to reducing the strength, such softening does not improve the elongation of the alloy material, resulting in a lower elongation rate than that of the naturally aged alloy material and the sub-aged alloy material. In addition, the more specific treatment temperature in sub-aging treatment is appropriately determined depending on the alloy composition and material shape of the alloy material, and similarly, the treatment time in natural aging treatment and sub-aging treatment also depends on the alloy composition and material shape of the alloy material. It will be determined appropriately depending on the shape and the aging treatment temperature.

The alloy material that has gone through all the processes described above will be used as a material for cooking stoves, etc., but the aluminum alloy material manufactured according to the method of the present invention is subjected to deaeration treatment within a specific range. The elongation rate is significantly improved by being molded and heat-treated under specific conditions after molding, so the material may crack during cutting or machining, or the edges of the material may be chipped. There was no longer anything to do.

(Examples) Below, some examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited in any way by the description of such examples. Needless to say, it is not something that can be accepted.

In addition to the following examples and the above-mentioned specific description, the present invention includes various changes, modifications, and changes based on the knowledge of those skilled in the art, as long as they do not depart from the spirit of the present invention. It should be understood that improvements and the like may be made.

First, Si: 17% by weight, Fe: 6% by weight, Cu: 4.
5% by weight, Mg: 0.5% by weight, Mn: 0.4% by weight, and the remainder consists of 82 and inevitable impurities. -St-Fe alloy? aluminum alloy powder was produced by an atomization method. Next, the obtained alloy powder was filled into an Al can and sealed, followed by various degassing treatments, followed by a molding temperature of 450°C,
Extrusion molding was carried out at an extrusion ratio of 15 to form a bar with a diameter of 18 plates.

The bars thus obtained were subjected to various heat treatments, and then their tensile properties and fatigue strength were examined. The test results are summarized in Table 1 below, along with the degassing treatment conditions and heat treatment conditions for each test material. The solution treatment in each example was carried out over a period of 2 hours.

As is clear from Table 1, Nα2 and No. In the case of alloy material No. 4, its elongation was significantly improved, and both tensile strength and fatigue strength were found to be good.

On the other hand, although the degassing conditions were met, No. 1 was subjected to solution treatment at a temperature lower than 460°C. The alloy material No. 3 has insufficient tensile strength and elongation of Na. 2,
It can be seen that the fatigue strength is lower than that of alloy material No. 4, leaving room for improvement, and that the fatigue strength is the lowest among the four examples. In addition, although the heat treatment conditions match, the Nα1 alloy material whose degassing treatment time is less than 5 hours has slightly improved tensile strength and elongation, but compared to the Nα2 and 4 alloy materials, the tensile strength and elongation are slightly improved. It is clear that there is room for improvement.

Performer: Sumitomo Light Metal Industries, Ltd.

Claims (2)

[Claims] (1) After sealing an aluminum alloy powder containing Si: 15 to 35% by weight and Fe: 0.3 to 9% by weight as main alloy components, 5 to 1
Perform vacuum degassing treatment for 00 hours, then mold,
A method for producing an aluminum alloy material, which comprises subjecting the obtained molded product to solution treatment at a temperature of 460° C. to 500° C., followed by water or hot water quenching and natural aging. (2) After sealing an aluminum alloy powder containing 15 to 35% by weight of Si and 0.3 to 9% by weight of Fe as main alloy components, 5 to 1
Perform vacuum degassing treatment for 00 hours, then mold,
The obtained molded product is subjected to solution treatment at a temperature of 460°C to 500°C, then water or hot water quenching, and further 1
A method for producing an aluminum alloy material, characterized by performing an artificial aging treatment at a temperature of 85° C. or lower for a time shorter than that required to obtain maximum hardness.