JPS58209418A - Method of high temperature hydrostatic extrusion for metal - Google Patents

Abstract

PURPOSE:To prevent surface oxidation and the growth of crystal grain, by supplying a combustion improver used for burning a soot of hydraulic medium sticking to the outside of a die, and providing a cooling zone successively, directly after extruding a material by means of a high pressure hydrostatic extrusion. CONSTITUTION:A hot billet 2 is charged into a container 1, and a hydraulic medium 3 is filled in the outer circumference of the billet 2 by utilizing the container 1, then the billet 2 is formed into a desired extruded material 5 by means of a high pressure hydrostatic extrusion with the aid of a die 4 through an extruding stem. At the same time, by utilizing a block 6, etc. surrounding the extruded material 5 loosely, a combustion-supporter circulating area A is formed between the block 6 and the material 5. A sticking carbon is burned by feeding a combustion improver to the area A from a feeding port 7. Next, the material is cooled by feeding cooling water from a feeding port 9 to a water cooling area B formed in the same manner as that of the area A.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to high-temperature isostatic extrusion in which a billet is hydrostatically extruded from a die at high temperature using an organic pressure medium. This invention relates to a product that solves problems such as coarsening of crystal grains and surface oxidation due to delay, and makes it possible to obtain high-quality extruded products.

High-temperature isostatic extrusion involves heating a billet made of steel or nonferrous metal to a high temperature, placing it in a container, filling the area around the billet with pressure medium, and extruding it from a die through a stem or mandrel to obtain the desired extruded material. The means are
It is well known that it is widely used in various fields due to its advantages such as high extrusion ratio and high speed processing.
Such high-temperature isostatic extrusion methods commonly have the following points. In other words, the organic pressure medium 1:1 agent adheres to the surface of the extruded material to the extent of several micrometers, and during high-temperature extrusion, it turns black or grains, staining the surface of the extruded material and causing defects in the surface area. Furthermore, since materials extruded at high temperatures require time to cool down, the crystal grains of the extruded material tend to become coarser during this time.For example, in non-ferrous metal H materials, In brass, which is one type of brass, if such coarse grains are formed, the surface will become rough during drawing after extrusion, resulting in a decrease in quality.Furthermore, if the product is extruded at high temperatures and left in the atmosphere, The pressure medium and lubricant adhering to the surface of the extruded material turn black, which then burns and develops into surface oxidation, and this phenomenon is particularly noticeable in pure copper, nickel-copper alloys, and diseased steel.

The present invention has been made to solve these problems, and includes extrusion using high-temperature isostatic pressure extrusion. Immediately after, a combustion aid is supplied to the exit side of the die to combust the attached pressure medium, and then a cooling layer is provided to prevent surface oxidation and grain growth. The feature is that the billet is hydrostatically extruded from a die at high temperature using an organic pressure medium, and a combustion improver is supplied to the outer surface of the extruded material on the exit side of the die. The pressure medium adhering to the outer surface is combusted, and the extruded material is then cooled with water.The characteristic of this method is that the billet is made of copper or a copper alloy, and the combustion aid is air, and its supply IQ = K
-d"・R-v j/min (where d is the outer diameter of the extruded material, R is the extrusion ratio, V is the extrusion speed S, and wI is the constant 1.4
±0.1, K is constant 0.00067≦≦0.0018
).

The present invention will be described in detail below based on the illustrated embodiments.Heating L
When looking at the thickness of the adhering carbide (pressure medium) on the surface of the extruded material when the billet is charged into a container, filled with an organic pressure medium around the billet, and extruded, the extrusion ratio is 1. 100, billet heating temperature 80
When a copper alloy tube is extruded using a pressure medium heat-resistant pleat at 0°C, the thickness of the carbide is measured by EPMA.
The maximum carbon adhesion was 1.4 μm. Therefore, in order to burn off such adhering carbides, it is sufficient to supply a combustion improver to the room where the extruded material is at a high temperature, and to combust it through the heat of the extruded material itself.

for example! As shown in the experimental example shown in Figure $1.

A heated billet (2) charged in a container (1) is filled with a pressure medium (3) around the outside of the billet using a container fil, and this billet (2) is passed through a die (not shown) through an extrusion stem (not shown). 4), the desired extruded material (5) is obtained by high temperature isostatic extrusion, and the die (4) is
On the exit side of the extruded material i5), use the block +61* that loosely surrounds the same block (6) and the extruded material i5).
6) A combustion improver distribution channel 11A (A) is formed in a space between the extruded material and the extruded material into which, for example, air or other combustion improver is extruded through the supply port ()) into this area (A). :11) so that it can flow. At this time, the supply port (7
) may be directly supplied into the factory (A), or 1.
It may also be supplied through a partition wall (8) made of a perforated plate as shown in the figure.

However, when supplying a combustion improver to burn the adhering carbide, care must be taken to ensure that the combustion is not insufficient and the adhering carbide does not remain, and that the combustion is not sufficient and oxidizes too much. It is necessary. This study examined the necessary or minimum conditions for obtaining an extruded material with a beautiful surface by variously changing the supply time and supply of the uninvented combustion improver. -C1 surface oxidation (with no significant difference in appearance) was used as the supply material, and the extrusion conditions were as follows:
Heating temperature 6900℃, extrusion stem extrusion method Pi 50 t
x4/s a c, extrusion ratio 51, 12 (as a result of repeating each base experiment under the condition of using air as a 1% combustion improver,
The following things became clear.

In other words, the air supply lid is proportional to the amount that the extruded material surface passes through the combustion zone per unit time, so the air supply M°quQ
=x-df''・Re v 7/min is found. In the above equation, K and m are constants, d is the outer diameter of the extruded material (m), R is the extrusion ratio, and V is the extrusion speed. (
wIy'S) of the stem, and the internal constant m of the above constant is a constant determined by the die angle, extrusion speed, and viscosity of the pressure medium, and was found by experiment to be ff1 = 1.4 ± 0.1. did.

According to the experimental results obtained in this way, the relationship between the surface quality of the extruded material made of cupola nickel material and the extrusion conditions is as shown in the graph of Figure 2, where the vertical axis is the air supply amount Q, and the horizontal axis is The axis is the outer diameter of the extruded material d, but in the same figure, the boundary to prevent surface oxidation is % (Q
= 150 l/rnin, d - = 6.2 x),
(Q ” 118 //min, d = 9.5
m'), and the constant at this time is represented by the constant m
The value of i, i KO60018%ff11.44,
Similarly, in order for no unburned carbide to remain on the surface, the value of the constant is 0.0006'/, and the value of the constant m is Vi1.14. In this case, the constant m should originally be m = 1, but since the thickness of carbide attached to the surface of the extruded material changes depending on the extrusion ratio, in reality m = O, and in general, Vm) h It is.

When the results of the above experiments are organized in terms of the relationship between the air supply area passage time and the air supply amount, the graph shown in FIG. 3 is obtained. In other words, the figure is a graph showing the influence of air supply conditions on the external surface quality of extruded materials.The vertical axis is the combustion time, and the horizontal axis is the air supply amount, which indicates the passing time to obtain a beautiful surface. Although it varies depending on the air supply area, for example, when the air supply m is 140 l/min, it is 0.13 seconds, and when the air supply m is 70 jl/min, it is 0.35 seconds or less. At this time, if the amount of air supplied is small, the passage time can be increased, but in this case there is a disadvantage that the temperature of the extruded material decreases less and coarse grains grow.

After extrusion using cuboronickel material of the above-mentioned test material.

Even when left to cool in the air, extremely coarse crystals do not occur, so crystal grains grow quickly, and this causes problems with rough skin during drawing. As a result of conducting repeated experiments and examining the length of the region, the following conclusion was reached regarding the length of the air supply region that can prevent coarsening of crystal grains.

That is, as the extrusion conditions, a billet made of aluminum brass material (68, wx-x200, l) was used, and the heating temperature a was
o.

°C, extrusion speed I! t1. '7 W/S, extrusion ratio 40. The extruded material size is 22.0, -DDX 1.5 mt, and air is 2017m i :+ as a combustion improver.The extrusion device is as illustrated in Fig. 4, in which fl+li container, (2) is a billet, 13H- as pressure medium, (4)
is a die, and these structures are the same as those described above in Fig. 1, but a distribution area (A) with air supply similar to that in Fig. 1 is provided on the exit side of the tono die (4). The length of is 0.7 m, and the supply is made from [-] (9) surrounding the outer surface of the area shown in FIG. In the apparatus shown in FIG. 4, the water cooling area (B) to which cooling water is supplied has a length of 1.2 m and 1°.

In addition, in the experiment using the apparatus shown in Fig. 4, in order to see the effect of water volume, the water volume was varied from 0 to 36 l/min.
This is a comparison of the implementation and the case of using an aquarium. Regarding the experimental results, firstly, the relationship between the amount of cooling water and the grain size is as shown in Figure 5, which shows the effect of the amount of cooling water on the grain size of the extruded material (extruded raw tube obtained in Figure 4). In the graph that shows the graph, does the vertical axis show the grain size and the horizontal axis show the amount of cooling water?

As is clear from the figure, when the cooling water is ii Ol/min, the average grain size is 0.07 m. It can be seen that the crystal grain size is less than .04t).

That is, a billet made of aluminum brass material is extruded to make a raw pipe,
When extrusion plate drawing is performed on this material, the smaller the crystal grain size, the more beautiful the surface texture will be.

Considering that the graph of the relationship between cold working rate and grain size shown in Figure 6 shows that the grain size is 0.04 tm or less, the surface texture can be sufficiently settled even in one or two passes of drawing. You can get something good.

Therefore, when an air circulation area (A) of 0.7 m is provided on the exit side of the die, the extrusion speed is 1.7 m/s, so the passage time ij of this air supply area is 0.41 seconds, and as shown above, the extrusion speed is 1.7 m/s. From the results shown in FIG. 3, it can be seen that the time is sufficient to completely burn out the adhering carbide (organic pressure medium) on the surface of the extruded material.

The present invention has been comprehensively obtained from the above experimental results, and is based on the method of supplying a combustion improver (air or other) to the surface of the extruded material immediately after extrusion on the exit side of the die to release the pressure medium that is the admixture thereof. Let it burn completely, and furthermore, this j! ! ! Water cooling is performed following burning removal. First, by burning off the adhering carbides, the extrusion surface p1 is cleansed and made beautiful. This means that it is possible to prevent the grain from becoming coarse and also to prevent surface oxidation, thereby eliminating the problems of the prior art. At this time, crystal grain growth of copper-based metals progresses when the temperature exceeds 500°C, so it is preferable to rapidly cool the metal in the shortest possible time. As in the present invention, the adhering carbide can be burned off by cooling it with water after the combustion zone has been conducted in advance. This makes it possible to easily obtain an extruded material with a beautiful surface texture while preventing the extrusion from occurring, and this is highly effective as it also prevents the roughness that tends to occur during drawing processing after extrusion. ) Also, the problem of surface oxidation caused by extruded material extruded at high temperature being left in the atmosphere is reliably prevented by the combustion removal of adhering carbide immediately after extrusion and subsequent water cooling of the present invention. It is particularly effective for metal materials, and the surface of extruded materials produced by high-temperature isostatic extrusion is
209418 (4) Accurately prevent deterioration of and improve its quality.
This is what was modeled in 7.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an embodiment of the method of the present invention, Fig. 2 is a graph showing the relationship between the surface quality of the extruded material and extrusion conditions, Fig. 3 is a graph showing the relationship between the same surface quality and air supply conditions, and Fig. FIG. 4 is an explanatory diagram of an embodiment of the method of the present invention, FIG. 5 is a graph showing the relationship between crystal grain size and cooling water storage, and FIG. 6 is a graph showing the relationship between cold working rate and crystal grain size. (1) Container, (2) Billet, (3)
...Pressure medium, (4)...Dice, (A)...Combustion improver distribution area, (B)...Water cooling area.

Claims (1)

[Scope of Claims] 1. A method of isostatically extruding a billet from a die at high temperature using an organic pressure medium, in which a combustion improver is supplied to the outer surface of the extruded material on the exit side of the die to improve the quality of the extruded material. A method for high-temperature isostatic extrusion of metals, characterized in that the pressure medium adhering to the outer surface is combusted, followed by water cooling of the extruded material. 2 A method of isostatically extruding a billet from a die at high temperature using an organic pressure medium, in which a combustion improver is supplied to the outer surface of the extruded material on the exit side of the die, and the pressure is applied to the outer surface of the extruded material. The medium is combusted, and then the extruded material is water-cooled, the billet is made of copper or a copper alloy, the combustion improver is air, and the supply ikQ is Q=, d″′
・R・v l/win (where d is the outer diameter of the extruded material, R is the extrusion ratio, ■ is the extrusion speed, and m is the constant 1.4
±0.1. J constant 0.0006'7≦≦0.001
8) A high-temperature isostatic extrusion method for metals based on the method described above.