JPH07801B2 - Manufacturing method of powder aluminum alloy extruded material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to the production of powdered aluminum alloy extruded materials, and more particularly to a method for producing extruded materials from aluminum alloy powder in good yield.

(Prior art and problems to be solved) Generally, in order to produce an extruded material from aluminum alloy powder, first, a relatively low density ratio (eg, 90%) is obtained by using an appropriate molding machine such as a cold isostatic press. % Aluminum alloy powder compact (billet).

Next, since this billet contains gas components such as H ₂ and H ₂ O, the billet is heated and degassed, then charged into an extruder and extruded. As a result, sintering and molding are performed to obtain an extruded material having high true density.

By the way, when the billet is extruded, in the case of so-called continuous pushing in which a plurality of billets are continuously charged into an extruder and extruded, if the billet end surface comes into contact with air when the billet is taken out of the furnace after degassing, Since the mechanical properties in the longitudinal direction of the extruded material corresponding to the end face are not continuous, it is necessary to cut and remove this part. Therefore,
To increase the yield of extruded material, it is advisable to use a long billet. However, increasing the length of the billet requires expensive and large molding equipment, which in turn increases the cost. Further, since the billet unit weight increases, there arises a problem that handling becomes difficult.

The present invention solves the above-mentioned drawbacks of the prior art and is a method capable of producing a powder aluminum alloy extruded material having a high quality and a low quality over its entire length without causing problems of quality such as mechanical properties, even without lengthening the billet. It is intended to provide.

(Means for Solving Problems) In order to achieve the above-mentioned object, the present inventor has made various studies on the production of an extruded material by a conventional splicing, and before extruding a billet produced from an aluminum alloy powder. Although the billet is heated and degassed, the billet end face reabsorbs H ₂ O contained in the air once the billet is taken out into the air outside the furnace. Even if extrusion is performed by pushing the end faces against each other and pushing them into the extruder container body, after extrusion, the amount of H ₂ is high in the part corresponding to the billet joint interface, the mechanical properties are worse than in other parts, and the state is discontinuous. It turned out to be.

Therefore, in order to solve this problem, the present inventor recommends that the contact interfaces of a plurality of billets before being continuously pushed are loaded into an extruder in a clean state obtained by heating and degassing. For example, the effect of degassing can be maintained, the billet contact interface can be effectively connected by the incineration reaction during extrusion, and the structure and mechanical properties will be similar to those of other parts, and can be made uniform over the entire length. The present invention has been made based on the knowledge that

That is, the method for producing a powdered aluminum alloy extruded material according to the present invention, a plurality of aluminum alloy powder compacts are placed in the same container, heated in a vacuum or an inert gas stream, and degassed, and then the compacts are molded. It is characterized in that the end faces are brought into close contact with each other, taken out of the furnace, directly inserted into an extruder and extruded.

The present invention will be described in detail below.

Molded billet of the powder aluminum alloy that is the subject of the method of the present invention is molded by a conventional method so as to have a relatively low density ratio such as 80% or less, but before heating it for extrusion, when degassing, First, it is desirable to grind the outer surface of the forming billet by 1 mm or more to expose a clean surface. As a result, lubricant, thread waste,
Oils and fats and other harmful foreign substances are removed.

Next, a plurality of billets are set in the same container so that the end faces thereof are in close contact with each other in the longitudinal direction and are continuously in contact with each other. The container for this purpose may be the same as the conventional one, for example, a container made of an aluminum alloy and having a shape such as a tubular shape with at least one end opened.

The above container is placed in a heating and degassing furnace and subjected to degassing treatment. As a result, gas components such as H ₂ and H ₂ O on the billet surface and inside are removed or reduced, resulting in a clean state. The conditions of heating and degassing may be the same as conventional ones and are not particularly limited, but it is necessary to heat at least for a required time in a vacuum or an inert gas stream such as Ar gas.

After heating and degassing, the end faces are in contact with each other, leave them in the container, take them out of the furnace, and set them on the billet supply table of the extruder. The billet of the book is pushed into the extruder container body and extruded. During this extrusion, the contact interface between the billets is free from lubricant, thread scraps, oils and fats and other harmful foreign substances during billet molding, and the heating and degassing conditions are maintained. , So H ₂ ,
Since there is no concentration of gas components such as H ₂ O, no trace of the billet joint interface is observed in the extruded material after extrusion, which is no different from the extruded material obtained by extruding a single long billet. Therefore, the structure, mechanical properties, etc. are uniformly distributed over the entire length, and an extruded material having no quality problem can be obtained.

In the present invention, it goes without saying that the aluminum alloy powder used as the starting material does not have to be a special material, and heating, degassing conditions, extrusion conditions and the like may be normal conditions.

Next, examples of the present invention will be described.

(Example) Two billets of 200φ x 300 lmm size were molded from an aluminum alloy powder consisting of Al-20% Si-3.5% Cu-1.5% Mg-5% Fe in weight%, and end faces of these billets contact each other. Then, it was loaded into an aluminum alloy container.

Then, the container was heated and charged into a degassing furnace, heated and held at 480 ° C for 1 hr in an argon stream, and then cooled to 430 ° C in the furnace, and then two billets were brought into close contact with each other in the container. In this state, the product was taken out of the furnace, sequentially pushed into the container body of the extruder, and extruded with a 54φ-hole die.

On the other hand, for comparison, two billets of the same material and size are heated and separated separately in the degassing furnace, heated and degassed, taken out of the furnace, and then extruded with the billet end faces contacting each other. It was pushed into the machine and extruded.

The H ₂ gas distribution in the longitudinal direction was measured for each of the obtained extruded materials. The results are shown in FIGS. 1 and 2. In the case of the extruded material by the conventional method, while showing the H ₂ gas distribution in the peak state in which a large amount of H ₂ is contained in the joining interface between the trailing end of the leading billet and the leading end of the trailing billet,
Extruded materials according to the inventive examples exhibit such a peak-free H ₂ gas distribution, exhibiting the same low level of H ₂ content over the entire length.

Further, for each extruded material, a test piece was cut out from the joint interface portion and other portions, and a tensile test was performed. In the case of the extruded material according to the present invention example, the same tensile strength (53 kgf / mm ² ) was shown, whereas in the case of the extruded material by the conventional method, the tensile strength of the joint interface was The value is much smaller than that of the part (45 kgf / mm ² ), indicating that the billet joint interface has different mechanical properties.

(Effects of the Invention) As described in detail above, according to the present invention, a plurality of powder aluminum alloy molding billets are heated and degassed in a state where their end faces are in close contact with each other, and extrusion is performed in that state. The billet contact interface is joined with the same structure and mechanical properties as other parts. Therefore, it is not necessary to cut and remove the contact interface portion as in the conventional case, and the yield of the extruded material can be remarkably improved. Moreover, since a short billet can be used, the molding equipment can be compact and economical. The billet is also easy to handle.

[Brief description of drawings]

Figure 1 is a diagram showing a longitudinal H ₂ gas distribution of the extruded material after and billets Tsugi押by the conventional method, FIG. 2 longitudinal of H ₂ extruded material after and billet Tsugi押according to an embodiment of the present invention It is a figure which shows gas distribution.

Claims (1)

[Claims] 1. A plurality of aluminum alloy powder compacts are placed in the same container, heated and degassed in a vacuum or an inert gas stream, and then the compacts are taken out of the furnace in a state where their end faces are in close contact with each other. A method for producing a powder aluminum alloy extruded material, which comprises directly charging the extruder and extruding.