JPH01215427A - Manufacture of bottomed metallic pipe - Google Patents

Abstract

PURPOSE:To manufacture a bottomed metallic pipe at a low cost by forming a recess on one end face of a columnar metallic blank, filling this surface with lubricant, then, carrying out cold extrusion with a punch having a specified shape. CONSTITUTION:After all the surface of a columnar metallic blank 1 is treated with lubricant, the recess 5 is preformed. Then, powdery lubricant 6 is mounted fully on this surface and then cold extrusion is performed by a punch 7. In this case, it is preferred that the tip of the part of a diameter D of the punch 7 has a flat surface 9 having a diameter over 0.3XD, the shoulder part 10 of the punch 7 has a corner radius over 0.1XD and the punch has tip angles alpha160-180 deg.. In this way, the bottomed metallic pipe free from seizure can be manufactured at a low cost.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides AQ, AQ alloy, Ti, Ti alloy, which has no seizure on the inner surface of the tube, has small thickness deviation, and has excellent dimensional accuracy.
This invention relates to a method for manufacturing a metal tube with a bottom by cold backward extrusion of C11% Cu alloy, steel, etc.

(Prior technology) When manufacturing bottomed metal tubes for use in gas cylinders, etc., the entire surface of a cylindrical metal blank is first lubricated with a lubricant, and cold backward extrusion is performed. L (hole depth) / D” (
The hole diameter) ratio (hereinafter referred to as L/D' ratio) was up to 4.0. When manufacturing a bottomed metal tube with a depth greater than this value, ironing or cutting had to be performed as a separate process. Also, the tip shape of the punch at this time has a tip angle α of approximately 170° and a corner radius of 0.
10 (D is the diameter of the tip) or less, and there was no flat surface.

For example, Fig. 3 shows the case of ironing. First, the cylindrical metal blank 1 shown in Fig. 3 (a) is first heated, and the raw metal tube 2 with /D' of 4.0 or less is cold-rolled. Manufactured by extrusion. See Figure 13 (b), then annealing.
After applying lubrication treatment, L/D'4 is achieved by ironing.
．． The metal tube 3 with a bottom of 0 or more is used. See Figure 3 (c).
In addition, Fig. 4 shows the case of cutting processing, but Fig. 4 (
The cylindrical metal blank 1 shown in a) is subjected to hot backward extrusion, and as shown in FIG.
After the raw metal tube 2 with the above-described deep holes is prepared, it is finished by cutting to manufacture the metal tube 4 with a bottom. Figure 4 (c)
Refer to this method, which requires post-processing such as the short life of the punch due to the high heat, and the poor surface roughness of the base metal tube with a bottom, as well as poor dimensional accuracy, which requires finishing by cutting.

As described above, both the former and the latter have been high in cost.

(Problems to be Solved by the Invention) As described above, in the conventional method, when manufacturing a metal tube with a bottom, after performing a lubrication treatment on the entire surface of the blank material (material for the metal tube with a bottom), hot drilling is carried out. (hot backward extrusion) or cold backward extrusion.

However, when hot backward extrusion is used, cutting is required to adjust dimensional accuracy and surface condition as a post-process, which requires extra man-hours.

In addition, when cold backward extrusion is used, seizure spots occur on the inner surface, and only products with a small L/D' ratio can be manufactured. After that, annealing, lubrication, and cold processing are performed, which requires a lot of man-hours (and high costs).Also, with conventional punches, the bottomed tube cannot be The unevenness of meat was large.

Thus, an object of the present invention is to provide a highly efficient manufacturing method for producing a bottomed metal tube with a deep hole, excellent dimensional accuracy, and a large L/D' ratio, without causing inner surface seizure. That's true.

(Means for Solving the Problems) In order to achieve the above object, the inventors of the present invention have conducted various studies focusing on a cold backward extrusion method which has excellent dimensional accuracy and does not have uneven thickness, instead of a hot backward extrusion processing method. layered. Although the cold backward extrusion method is possible even with conventional technology, for example, a metal tube with a bottom for a cylinder has a L (hole depth)/D' (hole diameter) ratio of 4.
Because of the above requirements, if an attempt is made to manufacture the blank by one cold backward extrusion with only the entire surface of the blank lubricated, the inner surface of the tube will run out of lubrication and seize up, making it impossible to manufacture the blank.

Therefore, as a preliminary processing of a cylindrical metal blank, inventor 2 first made a recess on one end surface, filled it with lubricant, and received the tip of the punch, thereby making it possible to perform stable molding from the beginning. The present invention has been completed based on the finding that by making the pipe as follows, it is possible to prevent seizure of the inner surface of the tube, to prevent uneven thickness, and to improve dimensional accuracy.

Therefore, the gist of the present invention is that when manufacturing a metal tube with a bottom, a recess is formed on one end surface of a cylindrical metal blank, and after the recess is filled with a lubricant, cold backward extrusion is performed. This is a method for manufacturing a metal tube with a bottom.

In cold backward extrusion molding as described above, the shape of the tip of the punch for forming may greatly affect the forming performance, and according to a preferred embodiment of the present invention, the flat rate of the punch tip is 0. The punch has a flat surface of 3 or more, and the corner radius of the shoulder at the tip of the punch is 0. It is preferable to perform the cold backward extrusion process using a punch having a diameter of I×D or more. Here, the ratio of the diameter d of the flat surface to the diameter of the punch tip is called the flat ratio, and the diameter of the punch tip is The diameter is approximately equal to the hole diameter D° of the extruded tube.

(Operation) Next, the present invention will be described in further detail with reference to the accompanying drawings.

The steps shown in FIGS. 1(A) to 1(E) are explanatory diagrams schematically showing the steps according to the present invention that make it possible to manufacture a bottomed metal tube with an L/D' ratio of, for example, 5 or more.

First, according to the present invention, after the entire surface of the cylindrical metal blank l shown in FIG. 1(a) is lubricated, one end surface (upper surface ) is preformed with a press punch, for example, to form a concave portion 5, and after placing and adding powder lubricant 6 so as to fill the concave portion 5, extrusion processing is performed, for example, using a punch 7 having the shape used in the present invention as shown in FIG. By carrying out this process, it is possible to manufacture a metal tube 8 with a deep hole and a bottom with excellent dimensional accuracy and no uneven thickness.

That is, in the present invention, for example, the entire surface of the metal blank 1 of a predetermined size, which is the material of the bottomed metal tube 8, is coated with Alpond,
After lubricating with Bonderite (trade name manufactured by Nippon Barikisha) or Bondarube (metal soap), the material is first formed by preliminary backward extrusion processing as shown in Figure 1 (b).
As shown in the figure, a shallow recess 5 is formed on one end surface of the metal blank 2, this recess 5 is filled with a powder lubricant 6 (for example, Ca stearate), and cold backward extrusion is performed using a punch 7 to form a metal tube with a bottom. You get 8.

In addition to the above methods, machining,
Any method such as hot pressing or warm pressing may be used.

The shape of the recess is located at the center of the blank, preferably in the shape of a disk, and its volume is sufficient to accommodate the lubricant required during cold backward extrusion pipe manufacturing.

If the volume of the recess is smaller than the amount of lubricant, the loss of lubricant will be large even if a solid lubricant is used, so preferably the volume of the recess is larger.

As shown in FIG. 2, the preferred shape of the punch 7 during cold backward extrusion pipe manufacturing is to have a flat surface 9 with a flat ratio of 0.3 or more at the punch tip, and a flat surface 9 with a flat ratio of 0.10 or more at the tip shoulder 10. It has curved corners as shown above. Reference numeral 11 indicates a land.
Note that the tip angle (α) of the punch is preferably 160 to 180°, and this affects the drilling force.

As shown in FIG. 1(D), when carrying out cold backward extrusion pipe making in this process with the lubricant 4 held at the tip of the punch 7, as the extrusion progresses, the lubricant 4 is held at the tip of the punch 7. The retained lubricant 6 gradually flows to the wall surface and lands 11.
The ratio of bottomed metal pipe L (hole depth)/D' (hole diameter) is 4 or more, generally 5.
The above items can also be easily manufactured. The lubricant placed in the recess may be liquid, powder, or solid when the extrusion is vertical, but it needs to be solid when the extrusion is horizontal.

Next, each step in the present invention and the reasons for limiting the preferred punch shape will be described below.

In the present invention, for example, a powder lubricant 6 is further added on the top surface of the metal blank 1, which has been completely lubricated, in order to prevent the inner surface of the metal tube from seizing when drilling a deep hole, and only the entire surface is lubricated. This is because lubricant is insufficient and seizure occurs.

A preferable amount of lubricant added to the upper surface of the metal blank 1 is expressed by the following formula.

Addition amount g/rrr-60x2'''·°-4) ±40% Note that this addition amount is the amount per unit cross-sectional area of the punch.

Moreover, solid soap of Ca stearate is preferable as this lubricant.

The reason why a concave preform is applied to one end (top surface) of the metal blank 1 is to prevent the lubricant placed on the top surface from easily escaping from the punch tip when the punch makes a hole, and to fix the punch tip. This is to have the effect of improving buckling stress and preventing eccentricity. The concave shape preferably has a shape corresponding to the tip shape of the preferred punch described above.

Further, compared to a horizontal press, it is preferable to use a vertical press because the punch does not bend, so there is less eccentricity, and the lubricant placed on the top surface does not fall off.

The reason why the punch tip flat surface diameter (d) is set to 0.3D or more (flat ratio is 0.3 or more) is to improve the eccentricity accuracy of the bottomed metal tube, and the flat surface diameter is 0.30D or more.
If the diameter is less than 0.3D, it will be difficult to prevent eccentricity, so the diameter of the flat surface is set to 0.3D or more. Further, although the upper limit thereof is not particularly necessary, it is preferably 0.95×D or less. The reason why the tip shoulder R is set to be 0.10 or more is because if it is smaller than this value, lubrication is likely to run out and the metal flow cannot be smooth, resulting in an increase in drilling force.

As described above, according to the present invention, a bottomed metal tube with a deep hole L/D ratio of 4 or more, generally 5 or more can be manufactured efficiently at low cost by using a cold backward extrusion method that does not cause seizure and has excellent dimensional accuracy. Can be manufactured well.

In this way, the method of the present invention eliminates the need for ironing or cutting, which was conventionally required, and enables L/D'
A bottomed metal tube with a large ratio can be manufactured efficiently at low cost.

The metal material used to form the bottomed metal tube according to the present invention is not particularly limited, but examples include AQ, AQ alloy, Tis Ti alloy, Cu, Cu alloy, and steel.

Next, the present invention will be explained in more detail with reference to Examples.

(Example) When manufacturing an aluminum wind pipe with a bottom specified in the dimensions of total length 220s, outer diameter 50an, inner diameter 43++n, and bottom thickness 12-, a diameter of 50mm + a was made from 6061 aluminum material.
+, cut out a 70m-long blank, and heat it at 400℃ for 1
After heating for a period of time, it was air cooled and annealed. Then, after lubrication using Alpond 3299 and Bonda Lube (both registered trademarks of Nippon Barcalizing), the tip flatness ratio is 0.6 and the shoulder radius is 0.2 using a vertical hydraulic press.
Preliminary backward extrusion was performed using a 0 punch to form a recess.Next, a powder lubricant (Ca stearate) was added to the recess.
) was met. The amount added was 100 g/d. The cylindrical metal blank thus prepared was subjected to cold backward extrusion using the same punch and a vertical press. By this backward extrusion, it was possible to manufacture a deep-hole bottomed tube of L/D'-5.3 with excellent surface roughness and almost no eccentricity.

There was no burn-in on the inside.

In addition, if lubricant is not added or if it is too little, seizure will occur, and conversely, if too much lubricant is added (for example, 500 g
/rrr) had horizontal cracks on its inner surface. Furthermore, even if a lubricant was added to the top surface without preforming, seizure could not be prevented.

The results are summarized in Table 1.

As can be seen from Table 1, according to the present invention, it is possible to manufacture a bottomed metal tube with a deep hole (large L/D' ratio) that does not cause seizure on the inner surface and has excellent dimensional accuracy. Effects) As described above, according to the method of manufacturing a metal tube with a deep hole bottom according to the present invention, the ratio of hole depth)/D'' (hole diameter) is 4.
A metal tube with a bottom of 0 or more can be manufactured by cold backward extrusion processing without causing internal seizure, with excellent dimensional accuracy, and making it possible to simplify the manufacturing process,
Therefore, the present invention is highly effective in reducing the manufacturing cost of bottomed metal tubes, and has great practical significance.

[Brief explanation of the drawing]

1(a) to 1(e) are schematic diagrams explaining the manufacturing process of the present invention; FIG. 2 is a schematic side view showing the shape of an extrusion press punch for carrying out the present invention; and Figures (A) to 3 (C) and Figures 4 (A) to 4 (C) are schematic explanatory diagrams showing the manufacturing process of a metal tube with a bottom according to the conventional method. l: Metal blank 2: Raw metal tube 5: Recess 6: Powder lubricant 7: Punch 9: Flat surface 10: Shoulder corner 11: Laundro: Punch tip diameter d: Flat surface diameter α: Punch tip angle

Claims (2)

[Claims] (1) When manufacturing a metal tube with a bottom, a recess is formed on one end surface of a cylindrical metal blank, and after the recess is filled with a lubricant, cold backward extrusion processing is performed. Method of manufacturing tubes. (2) If the diameter of the punch tip is D, the punch tip has a flat surface with a diameter of 0.3 x D or more, and the corner radius of the shoulder of the punch tip is 0.1 x D. The method according to claim 1, wherein the cold backward extrusion process is performed using the punch described above.