JPH0471609B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field This invention is particularly suited for use in engine cylinders, pistons, compressor vanes, etc., which require both wear resistance, heat resistance, and a low coefficient of thermal expansion. This invention relates to a method for producing Al-Si aluminum alloy extrusions. Definition In this specification, all "%" indicates weight %. BACKGROUND ART Conventionally, as wear-resistant aluminum alloys, Al-Si alloys to which Si is added as an element to improve wear resistance are well known. However, in the case of alloy materials used for applications such as pistons and cylinders for internal combustion engines, it is strongly required that they have excellent wear resistance and heat resistance as well as a low coefficient of thermal expansion. To meet these demands, as an element to improve the heat resistance of aluminum alloys,
It is well known that addition of high melting point metals such as Fe, Cr, Mn, Ni, and Ti is effective, and high melting point metals are also effectively used as elements to lower the coefficient of thermal expansion. However, aluminum alloys whose heat resistance properties have been improved by adding the above-mentioned high-melting point metal elements to Al-Si wear-resistant alloys have traditionally been mainly cast alloys (e.g. AC3A alloy,
AC8A-C alloy, etc.), and is hardly known as a wrought material. Problems to be Solved by the Invention However, as long as the above-mentioned conventional alloys are cast alloys, it is difficult to obtain a free product shape like a wrought material, and there are only limitations in terms of use. First, since the casting temperature of Al--Si alloys containing high melting point metals as described above is higher than that of general wrought materials, casting itself is difficult.
Furthermore, it is difficult to obtain a uniform and fine structure. In particular, recently, requirements for heat resistance and low coefficient of thermal expansion have become increasingly strict.
Even when using the casting method, it is becoming difficult to control intermetallic compounds due to high melting point metal elements added, making it difficult to obtain wear-resistant aluminum alloy materials with homogeneous mechanical properties and excellent high-temperature properties. The reality is that it was difficult. In view of the above-mentioned background, this invention is a wear-resistant aluminum alloy containing high-melting point metal elements and having excellent high-temperature properties, and is a manufacturing method that can efficiently produce high-quality extruded materials. This was done for the purpose of providing a method. Means for Solving the Problems Accordingly, the present invention employs a pressure solidification method in which a molten aluminum alloy is solidified under high pressure to produce a billet for extrusion. This was accomplished by discovering that even Si-based alloys can be cast uniformly and with a fine structure without any problems. That is, in the production of the wear-resistant aluminum alloy extruded material according to the present invention, the alloy structure contains Si; 4 to 40%, Fe; 0.5 to 20%, Cr; 0.5 to 20%, and Mn; 20%, Ni; 0.5 to 20%, Ti; 0.5 to 10%, Be; 1 to 20%, V; 1 to 20%, Y; 2 to 20%, Zr; 0.5 to 10% or Contains two or more types, or further contains one of Mg; 0.3 to 2%, Cu; 4 to 20%
In the manufacturing process, the above aluminum alloy is melted and the molten metal is
The method is characterized in that a billet is prepared by pressure solidification under a high pressure of 300 Kgf/cm ² or more, and then the billet is extruded. The reasons for limiting the above alloy components are as follows. As is well known, Si is an essential component for improving wear resistance. Si: By containing 4% or more, an effect commensurate with the amount added can be obtained, but it is preferably contained in a hypereutectic region of 12% or more. However 40
If the content exceeds %, extrusion becomes difficult. Therefore, in general, in order to find a balance between the requirements for wear resistance and ease of manufacturing,
It is desirable to adjust the amount within a range of about 30%. Fe, Cr, Mn, Ni, Ti, Be, V, Y, Zr are
Both have the significance of being added to improve the heat resistance of the alloy material and the high-temperature properties such as lowering the coefficient of thermal expansion, and in terms of this effect, they can be evaluated as substantially equivalent to each other in this invention. It is.
If the content of any element is less than the adjustment value specified above, the effect of improving the high temperature properties will be insufficient. On the other hand, when the content exceeds the upper limit, extrusion becomes difficult due to the formation of coarse crystallized substances. Further, Mg and Cu contribute to improving the strength of the alloy, but if Mg is less than 0.3% and Cu is less than 4%, the effect is insufficient. Also Mg; 2%,
Cu: Containing more than 20% of each does not significantly increase the above effects, but rather produces coarse crystallized substances and deteriorates mechanical properties. Next, to explain the reason for the limitations on the manufacturing process, aluminum alloys to which high-melting point metal elements are added to improve high-temperature properties cannot be cast using the conventional casting method used to manufacture conventional billets. It is difficult to manufacture billets due to the high casting temperature, and even if billets can be manufactured, it is not possible to obtain a uniform and fine structure, which not only makes extrusion processing difficult, but also makes it difficult to extrude the product. good mechanical properties cannot be obtained. The present invention overcomes these problems by employing a pressure coagulation method for billet production. That is. By melting the above aluminum alloy, pouring the molten metal into a pressurized solidification mold, and pressurizing and solidifying it to a predetermined degree of aggravation, a billet with fine grains and no defects can be produced. be. The pressurized solidification mold may utilize a container of an extruder. That is, the molten aluminum alloy may be directly injected into the outer container and solidified while being pressurized by the stem. Of course, in this case, it is necessary to close the entire surface of the container with a blind die to prevent the molten metal from spouting out during pressurized solidification. In addition, when pouring the metal, prepare the mold in advance.
It is desirable to heat it to about 300 to 350°C. This makes it possible to obtain a finer texture in the billet. That is, if the temperature is less than about 300°C, solidification of the aluminum starts immediately after pouring, making it difficult to fully achieve the effect of pressure solidification. On the other hand, if the material is heated to a high temperature exceeding 350° C., the cooling rate slows down, and crystallized substances tend to grow, making it difficult to sufficiently achieve the above-mentioned refinement effect. Immediately after pouring, the molten metal in the mold is pressurized by a pressurizing piston to advance solidification, thereby producing a billet. That is, a billet is produced by a pressure coagulation method. The pressurizing force at this time must be at least
It is necessary to set it to 300Kgf/cm2 or ^more ,
Preferably, it is about 500 to 1000 Kgf/cm ² . In this way, by solidifying the aluminum alloy under a predetermined pressurized state, a small billet of crystallized material can be produced without causing casting cracks. Therefore, when billets are produced by conventional casting methods, it is possible to omit the subsequent heating homogenization treatment required to homogenize and refine the structure, and the thermal energy and treatment required for this purpose can be omitted. Time savings can be achieved. The magnitude of the above-mentioned pressing force does not have a great effect on the quality of the billet. However, 300Kg
If it is less than f/cm ² , the effect of preventing casting cracks and refining crystal grains by the pressure solidification method is insufficient, but on the other hand, even if a high pressure exceeding, for example, 1500 kg/cm ² is applied, the energy required increases. Rather, it is useless because it does not show a proportional improvement in effectiveness commensurate with that. One of the reasons why the crystallized material can be made finer by pressurized solidification is that the air space between the mold and the molten metal and within the molten metal disappears due to pressurization, and the cooling rate increases. It is assumed that The billet made by the above pressure coagulation method is
Next, this is extruded to produce the desired wear-resistant aluminum alloy material with excellent heat resistance. Here, the billet may be used in a solid state that has been cooled once, but preferably, as the pressure solidification progresses, the temperature of the billet becomes a temperature suitable for extrusion processing, for example, about 1/1 of the liquidus temperature. It is recommended that the pressure solidification process be completed when the temperature has decreased to about 2,000 ml and it is in a semi-molten state, and that extrusion be started by filling the container of the extruder as is without reheating. Ru. By adopting such a procedure, it is possible to omit the heating step of the billet during extrusion processing, saving energy and time required for heating, preventing coarsening of crystals due to reheating, and improving extrudability. It is possible to enjoy the benefits of improved manufacturing efficiency and reduced manufacturing costs of alloy extruded materials by preventing a decrease in Effects of the Invention As described above, the present invention contains Si as an element for improving wear resistance in a predetermined range in terms of composition, and Fe, Cr, Mn, Ni, Ti, Be, V, Y,
Since it contains a specified amount of one or more of Zr, it has excellent wear resistance and high temperature properties, and is suitable for wear-resistant parts used under high temperature conditions. It is possible to obtain an aluminum alloy material that can be used favorably. Moreover, in the manufacturing process, a billet is first prepared from the molten aluminum alloy by a high-pressure solidification method of 300 Kgf/cm ² or more, and then extrusion processing is performed, so that it is possible to produce billets with the above-mentioned composition. Although it is a wear-resistant aluminum alloy with excellent high-temperature properties, it is possible to obtain an aluminum alloy material with a uniform microstructure and excellent mechanical properties that cannot be obtained by casting methods. Therefore, forging and cutting as secondary processing can be easily performed, and the cost of wear-resistant parts can be reduced and the manufacturing yield can be improved. Examples Example 1 Next, examples of the present invention will be shown together with comparative examples.

[Table] Alloys with various chemical compositions shown in Table 1 above are melted to a liquidus temperature of +100°C, and the molten metal is poured into a pressurized solidification mold that has been preheated to approximately 280°C. It was pressurized to 1000 Kgf/cm ² and solidified under the applied pressure. Then, when the temperature has cooled to approximately 1/2 of the liquidus temperature, the pressure solidification process is completed,
The resulting semi-molten billet (diameter 75 mm, length
100mm) into the extruder container,
It was extruded into a round bar with a diameter of 12 mm. Here, the extrusion could be carried out without any problem with any alloy. Therefore, this extruded material was then solution-treated at 490°C, and then aged at 180°C for 7 hours, and each sample obtained was subjected to a heat resistance test.
In addition to examining the tensile strength and coefficient of thermal expansion at 300°C, we also conducted an abrasion resistance test. The results are shown in Table 2 below. The wear resistance test was conducted using an Okoshi type wear resistance tester (dry type), mating material: FC30, friction speed: 2.
The test was carried out under the conditions of m/sec.

【table】

[Table] As shown in Table 2 above, the aluminum alloy extrusions manufactured according to the present invention were manufactured using the same manufacturing process compared to the extrusions manufactured using comparative alloys with different compositions. However, it had better heat resistance, a lower coefficient of thermal expansion, and better wear resistance. Example 2 In order to confirm the effect of improving the mechanical properties of the extruded material by producing billets using the pressure solidification method, Al-10% si-10 having the alloy composition shown in Table 3 below was used.
Two types of aluminum alloy extruded materials, a sample of the present invention and a comparative sample, described below, were manufactured using an Al alloy consisting of %Ni.

[Table] (Sample of the present invention) A round bar shape of 12 mm in diameter was extruded in the same manner as in Example 1, except that the Al-Si-Ni alloy shown in Table 3 was used and the pressurizing force during billet casting was 1300 Kgf/cm ² . A sample consisting of wood was obtained. (Comparative sample) The molten Al-Si-Ni alloy shown in Table 3 was solidified using a die casting method without applying pressure to produce a billet, which was then extruded into a round bar shape of 12 mm in diameter according to Example 1. A sample was made of wood. The metal structures of the above-mentioned inventive samples and comparative samples were examined using an electron microscope in the as-cast billet state and in the extruded material state after extrusion processing, and the results are shown in Figures 1 and 2. It was as shown in. Figure 1a shows the metallographic structure of the billet obtained from the sample of the present invention, and compared to the metallographic structure of the billet of the comparative sample shown in Figure 2a, intermetallic compounds, especially Al ₃ Ni and primary Si, are sufficient. It can be seen that it has become very minute. Furthermore, in the case of extruded materials, the metal structure of the sample of the present invention shown in FIG. 1b has a relatively significantly finer microstructure than that of the comparative sample shown in FIG. 2b. I was able to confirm it. Therefore, further regarding the present invention sample and the comparative sample,
When their mechanical properties were investigated, they were as shown in Table 4 below.

[Table] As can be seen from the results in Table 4 above, the samples of the present invention are based on the fact that the billets are cast by the high-pressure solidification method, whereas the extrusion of the comparative samples whose billets are made by non-pressure die casting is It was confirmed that the mechanical properties were significantly superior to those of other materials.

[Brief explanation of the drawing]

Figures 1a and 1b are micrographs showing the metallographic structure of an Al-10%Si-10%Ni alloy billet produced by the pressure solidification method according to the present invention and an extruded material produced therefrom (sample of the present invention). (Magnification: 300x). Figures 2a and b show the metallographic structure of a billet made by the pressureless die casting method using the same alloy as above, and an extruded material (comparative sample) made from the billet. This is a micrograph (300x magnification).

[Claims]

1 Equipped with a nozzle driving pipe for driving material into the polling reel and a nozzle front guide for guiding the material to the nozzle driving pipe, the material after rolling is sequentially driven into the polling reel from the nozzle driving pipe. In a rolling equipment that performs winding, a first driving means for circularly moving the nozzle driving tube around a predetermined point on the extension of the nozzle driving tube in the exit direction as a virtual center;
and a second driving means for swinging the nozzle front guide using the inlet side of the nozzle front guide as a fulcrum, and the first driving means initializes the driving angle of the nozzle driving tube as winding progresses. The second driving means drives the nozzle driving tube so as to gradually change the angle from the horizontal direction, and the second driving means drives the nozzle driving tube at the same speed while the axes of the inlet end of the nozzle driving tube and the outlet end of the nozzle front guide are aligned. A nozzle control device for rolling equipment, characterized in that the nozzle front guide is driven so as to change in the direction of the nozzle.

Claims (1)

Fe; 0.5-20%, Cr; 0.5-20%, Mn; 1-20%, Ni; 0.5-20%, Ti; 0.5-10%, Be; 1-20%, V; 1-20%, Y 2 to 20%, Zr; 0.5 to 10%, an aluminum alloy containing one or more of the following, the balance consisting of aluminum and unavoidable impurities is melted, and the molten metal is subjected to high pressure of 300 kgf/cm ² or more. 1. A method for producing a wear-resistant aluminum alloy extruded material, which comprises producing a billet by solidifying under pressure, and then extruding the billet.