JP2530331B2 - Aluminum profile high speed extrusion die - Google Patents

Description

TECHNICAL FIELD The present invention relates to an aluminum profile extrusion die, and more specifically to a die capable of high speed extrusion.

(Prior Art) Extrusion of aluminum profiles for building materials such as buildings and homes, which has been conventionally performed industrially, has been made as 6063 as a raw material.
An alloy billet and a JIS-SKD61 equivalent material were used for the die, and the extrusion speed was in the range of about 40 to 50 m / min.

For improving the die for improving the extrusion speed of aluminum profile, special surface hardening treatment (nitriding, boriding, etc.) on the bearing surface of the die, improvement of machining accuracy of the die, or super hard material of the entire die material Have been proposed. For example, according to Japanese Patent Publication No. 56-21843,
As a method capable of increasing the processing speed of aluminum screws, a method of forming a diffusion layer of nitride or boride on the work surface of a mold (in particular, an extrusion die) and then adhering a metal or lubricant layer thereon (Problems to be solved by the invention) Conventional die improvement proposals for high-speed extrusion include a curing method for curing a die in contact with aluminum, devising a material, or a die for passing a shape. Although it was based on the improvement of the accuracy of the holes, when the former proposal was carried out, there was a problem that continuous extrusion was impossible due to frequent occurrence of surface defects such as skin roughness and die lines on the surface of the profile in high-speed extrusion, The cost of the dies increases, and if the latter proposal is implemented, the dies must be replaced frequently and extrusion must always be performed with new dies with high precision. There was a problem. The inventor has found that the conditions such as the billet heating temperature and the number of times of die change are almost the same as those in the conventional method, and the extrusion speed is 50% of
Research was conducted to propose a high-speed extrusion die that can achieve the above increase.

(Means for Solving Problems) According to the present invention, a front surface of a die body made of die steel for extruding an aluminum profile is provided with a die front surface made of a sintered material containing carbide and / or nitride as a main component at a high temperature. The present invention relates to a high-speed extrusion die, which is closely contacted by pressing.

The die of the present invention has a structure in which a high-hardness sintered material is brought into close contact with the front surface of a main body made of usual die steel for extruding an aluminum profile. That is, since a die that uses a high-hardness sintered material as a whole has a high risk of damage and is expensive, it is assumed that the structure of the die that uses ordinary die steel is improved. By examining various parts of the die made of sintered material, it was found that the conventional method of using the entire die as a sintered material inevitably suffers from the problem of breakage, and the die front side is compounded. Was adopted as the basic structure of the die of the present invention. Therefore, the die of the present invention is a composite die composed of a front surface portion and a main body portion (rear surface portion), and holes are formed in the respective portions to allow the shape member to pass therethrough.

Furthermore, the die of the present invention is characterized by using, as a sintered material, one containing carbide and / or nitride as a main component. A boride or an oxide may be considered as a compound for improving the extrusion rate of the profile, but it is not as practically effective as a carbide or a nitride. As the nitride, titanium carbide, vanadium carbide, niobium carbide, chromium carbide or the like can be used. On the other hand, as the nitride, titanium nitride, niobium nitride, chromium nitride, or the like can be used. In addition to these nitrides and / or nitrides, die steel,
Alternatively, even if a small amount of iron, nickel, or the like is contained in the sintered body as a binder for joining them, the effect of the carbide or the like is not impaired. In the present invention, the sintered material used for the front surface of the die is a material which is separately sintered and has an appropriate shape such as a plate. That is, the surface of the die steel is treated with carbide and / or nitride (carburizing, nitriding, etc.)
The method of forming by means has many problems as a means for improving the extrusion rate, and a separately sintered material is effective. The reason for this is probably due to the stability of the tissue.

Furthermore, the die of the present invention is characterized in that the sintered material and the die steel are adhered to each other via a joining layer formed by high temperature pressure welding. Generally, when joining carbides, nitrides, etc. to steel, when these are heated to, for example, a melting temperature or a temperature close to the melting temperature, carbon and / or nitrogen is melted in the steel, which coarsely precipitates during cooling or hardening occurs. There is a cause that hinders the joining. The brazing method, which is a method for joining the carbide and the nitride to the die steel, is considered to be a good method because it does not have the above-mentioned causes of inhibiting the joining. Therefore, as a method of adhering both of these,
When the brazing method used for joining tips of cemented carbide tools was tried, strong joining was certainly obtained, but die damage was likely to occur at the joining surface during extrusion, and favorable results were not obtained. It was It is considered that this is because the joining surface becomes extremely hot during extrusion and the brazing material hardens. Therefore, as a result of further research, it was possible to obtain the result that high-temperature pressure welding enables strong joining of carbide and / or nitride and die steel, and that die damage does not occur at the joining surface during extrusion. did it. As shown in FIG. 2, the die formed by such high-temperature pressure welding has a joining layer 3 in which a portion of the sintered material (die front portion) 1 and a die steel (die body) 2 are mixed together as shown in FIG. It is a composite. A detailed microscopic examination of the structure of this bonding layer 3 reveals that in the steel matrix, the chromium carbide of the die steel,
An extremely complex structure in which carbide or nitride of the sintered material, a compound phase whose origin cannot be specified in both the sintered material and the die steel, and the like, and a part of the solidified structure during joining are observed. A directionality in which a secondary phase or the like is oriented in the pressure direction during joining is recognized in these structures. Judging from the characteristic structures such as these, (a) the sintered material (die front portion) 1 and the die steel (die body) 2 are joined together in a joining layer 3
By virtue of (b) the formation of coarse structure and the occurrence of cracks, which are factors that hinder the joining in the case of normal welding, are suppressed by the pressure during joining, and (c) even against the temperature rise during extrusion. It is considered that the structure, in which secondary phases such as carbides and nitrides are complicatedly intricately endured effectively, and the actions which are essential prerequisites for high-speed extrusion such as maintaining the bonding strength are obtained. Approximately 80 m / min to investigate the effects that directly cause high speed extrusion
Extrusion was performed using a normal die steel die and the die of the present invention at an extrusion speed of, and the interface between the aluminum and the die front surface was examined under a microscope. It was found to be burned into the die and aluminum was plastically flowing over the hard particles of the sintered material on the front side of the die of the present invention. Therefore, it is considered that the hard particles in the sintered material prevent seizure and accelerate the extrusion.
The action due to such plastic flow becomes remarkable in the die hole where aluminum is strongly reduced and its peripheral region.

Hereinafter, the present invention will be specifically described with reference to examples.

(Example) In FIG. 1, 1 is a front surface of a die made of a sintered material,
2 is a die body made of die steel. Reference numeral 4 is a baffle, 5 is a die case, and 6 is a backer, and these are normal extrusion device members used by being attached to the dies 1 and 2. For the die body 2, SKD61 is the most readily available and has a proven track record, so this is normally used. However, the same effect can be achieved by using a steel material suitable for extruding aluminum profiles. You can If the thickness ratio of the die front surface portion 1 and the die body 2 deviates too much to one side,
The effect of the composite die disappears, and only the same performance as the die of the die steel alone or the sintered material alone can be obtained. This ratio is preferably such that the thickness of the die body 2 is 1 and the thickness of the front surface of the die is 0.6 to 0.7. If it exceeds this ratio, the cost of the die increases, while if it is less than this ratio, there is a risk of damage to the die, and it becomes difficult to increase the extrusion speed. The heating temperature for joining the die front face 1 and the die body 2 is preferably in the range of 1100 to 1300 ° C. Below this temperature, the integration of the structure necessary for joining is not active, while above this temperature, the deformation of the die occurs, which causes an undesired effect on the structure of the die steel, so It is a preferable bonding heating temperature. It is desirable that the bonding be completed in the shortest possible time from the viewpoint of oxidation. After the composite die is manufactured as described above, the hole portion 7 (FIG. 3) through which the profile passes is formed in the die front surface 1 and the die body 2.

The extrusion method using the die of the present invention is a high-speed extrusion method higher than the normal extrusion speed, and even if continuous extrusion is performed at an extrusion speed of about 80 m / min, there is no problem in terms of profile quality and die life. .

Using a 6-inch billet, extrusion with an extrusion ratio of about 100 was performed using sintered material (thickness 16 mm, TiC50%, balance SKD61) and SKD6.
In an operation experiment conducted with a composite die consisting of 1 (thickness: 24 mm), 10 billets were extruded at an average speed of about 70 m / min to obtain all products.

(Effect of the Invention) According to the present invention, it is possible to increase the speed of extrusion of aluminum profile by compounding the dies. Therefore, there are many industrial advantages such as no need for additional equipment to increase production.

[Brief description of drawings]

1 and 3 are drawings showing an embodiment of an extrusion die of the present invention, and FIG. 2 is a conceptual diagram showing a joined state of a sintered material and a die steel. 1 ... Sintered material (die front part), 2 ... Die steel (die body), 3 ... Bonding layer, 4 ... Baffle, 5 ... Die case, 6 ... Backer

Claims (1)

(57) [Claims] 1. A front surface of a die body made of die steel for extruding an aluminum profile, and a die front portion made of a sintered material containing carbide and / or nitride as a main component are brought into close contact with each other by high-temperature pressure welding. High-speed extrusion die for aluminum profile.