JPH07113121A - Method for hardening thin-walled long tube whose one end is closed - Google Patents

Abstract

PURPOSE:To execute the hardening without causing the deformation to a thin- walled long tube by realizing the shrinkage fitting to a holding member to the outer circumferential side of the closed end of the thin-walled long tube whose one end is closed, and dipping the tube in the hardening liquid in the upright condition with the closed end downside. CONSTITUTION:A plurality of beams 22 made of steel are fixed to the bottom part of a harder basket 21 made of steel, and the respective holding members 23 are welded between two beams 22. The holding members 23 are formed of the metal whose coefficient of linear thermal expansion is smaller than that of a thin-walled long tube 1. The closed end 1a of the thin-walled long tube 1 (e.g. made of Al alloy) whose one end is closed is inserted into the holding members 23 to make the thin-walled long tube 1 in the upright condition, and the shrinkage fitting is executed by heating the tube using an air furnace, etc. When this hardening cage 21 is placed in the hardening liquid to be quenched, generation of the deformation of bending, crushing, etc. of the thin- walled long tube 1 is suppressed by the bouyancy to enable the hardening.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quenching a thin long tube whose one end is closed.

[0002]

2. Description of the Related Art A thin long tube made of, for example, an aluminum alloy and closed at one end is used as a pressure vessel (cylinder). Since the thin long tube used for such an application is required to have excellent mechanical properties, the thin tube is subjected to quenching treatment during its manufacture.

Conventionally, when quenching a thin long tube made of aluminum alloy and having one end closed, the heated thin long tube is put into a quenching solution and rapidly cooled as follows. The method has been adopted.

One of them is to arrange a thin long tube 1 having one end closed horizontally in a basket 11 as shown in FIG.
This is a method in which the thin long tube 1 is held from the upper side and the lower side by the horizontal rods 12 provided in the basket 11, and the basket 11 is lowered and immersed in the quenching liquid as shown by the solid line arrow in the figure.

As another method, as shown in FIG. 4 (b), a thin long tube 1 having one end closed is placed upright in a basket 11, and a thin rod 13 provided in the basket 11 is used for thin thin tube. This is a method of holding the tube 1 and lowering the basket 11 as shown by the solid arrow in the figure to immerse it in the quenching liquid.

[0006]

However, in the former method, when the basket 11 is placed in the quenching liquid and lowered as shown by the phantom line in FIG. The thin tube 1 may bend upward with the rod 12 as a fulcrum due to the resistance of the quenching liquid applied to the tube 1 and the buoyancy acting on the thin tube 1.

In the latter method, when the basket 11 is put into the quenching liquid as shown by the phantom line in FIG. 4 (b) and descends, the quenching liquid is added to the thin long tube 1 as shown by the broken line arrow. As a result of the added resistance due to the buoyancy and the buoyancy acting on the thin long tube 1, the thin long tube 1 floats and its upper end is in the basket 1.
1, the thin long tube 1 may be bent toward the side due to being pressed against the net 14 provided on the first thin pipe 1, and the upper end of the thin long tube 1 may be crushed.

There is a problem that the thin long tube 1 which is deformed such as bent or crushed cannot be shipped as a product.

The present invention has been made in view of the above circumstances, and one end of which can suppress the occurrence of deformation such as bending and crushing of a thin long tube when the thin long tube having one end blocked is put into a quenching solution and rapidly cooled. An object of the present invention is to provide a method for quenching a thin long tube having a closed tube.

[0010]

In order to achieve the above object, a quenching method of a thin long tube having one end closed according to the present invention is to heat a thin long tube made of metal and having one end closed. Together with the first step of shrink-fitting a holding member made of a metal having a thermal expansion coefficient smaller than that of the metal forming the thin long tube on the outer peripheral side of the closed end of the thin long tube; Then, the thin long tube is erected upright, a downward force is applied to the holding member to immerse the thin long tube in the quenching liquid and descend to rapidly cool the thin long tube. And a process.

[0011]

In the second step, when the thin long tube is pulled upright by the holding member in the upright state and descends in the quenching liquid, the lower end of the thin long tube is closed. On the other hand, buoyancy acts from the quenching liquid.

Since the lower end of the thin long tube is held by the holding member and pulled downward, the buoyancy acts on the thin long tube as a force to extend straight in the vertical direction. Therefore, the thin long tube is rapidly cooled without causing deformation such as bending and crushing.

Further, since the holding member for holding the closed end of the thin long tube is shrink-fitted into the thin long tube when the thin long tube is heated in the first step, the first step is performed. The thin long tube can be easily and surely held by utilizing it.

[0014]

EXAMPLE FIG. 1 shows an example of the quenching method of the present invention.
The description will be made with reference to FIG.

First, a thin long tube 1 made of metal and having one end 1a closed is prepared.

Examples of the metal which the thin long tube 1 is made of include aluminum alloys. The wall thickness of the thin long tube 1 is, for example, in the range of 0.1 to 10 mm. If it is less than 0.1 mm, it is not a heat treatment alloy, and if it exceeds 10 mm, it does not bend. The length is 300 m or more, and less than 300 m does not bend much. The closed end of the thin long tube 1 is the thin long tube 1
When used as a bottom or knot.

The first step will be described.

First, a quenching basket 21 shown in FIG. 2 is prepared. This quenching basket 21 has a frame made of steel, and the bottom of the quenching basket 21 is made of steel.
2, a plurality of holding members 23 are attached side by side.

Two beams 22 are arranged in parallel as one set and are hung on the lower portion of the quenching basket 21 and fixed by welding. A plurality of holding members 23 are arranged side by side with an interval between the two beams 22, and the two beams 22 are welded to each other.
It is fixed to.

The holding member 23 holds the closed end of the thin long tube 1 by shrink fitting, and is made of a metal having a smaller linear thermal expansion coefficient than the thin long tube 1, for example, soft iron.
The holding member 23 is a cylindrical body having a flange 23a formed at one end and an open other end, and is arranged with one end where the flange 23a is formed facing downward.

The inner diameter DB of the holding member 23 is larger than the outer diameter DA of the thin long tube 1, and the holding member 23
Also, the thin long tube 1 is heated to form a gap that can be securely shrink-fitted.

This gap has a size that satisfies the following formula. Outer diameter DA of thin long tube 1, inner diameter DB of holding member 23, linear thermal expansion coefficient CA of thin long tube 1, holding member 23
If the linear thermal expansion coefficient of CB is CB and the holding temperature T before cooling is D,
A * CA * T> DB * CB * T.

Two beams 22 and a plurality of holding members 23 are provided.
A plurality of combinations are provided in parallel in the lower part of the basket 21 with the combination of and as one set.

Then, as shown in FIG. 1, a quenching basket 21
Inside, each thin long tube 1 prepared is arranged vertically with its closed end 1a facing downward, and each closed end 1a is divided into two pieces.
It is inserted into a holding member 23 which is attached side by side to the beam 22 of the book. The closed end 1a of each thin long tube 1 contacts the collar 23a of the holding member 23. As a result, each thin long tube 1 is supported by each holding member 23 in an upright state.

Then, each thin long tube 1 is entirely heated to a predetermined temperature by using an air furnace, a salt bath furnace, an atmosphere adjusting furnace or the like.

Here, each holding member 23 holding each thin long tube 1 is also heated at the same time. The holding member 23 is shrink-fitted to the closed end of the thin long tube 1 due to the difference in expansion coefficient between the thin long tube 1 and the holding member 23. Thereby, the thin long tube 1 is held and fixed to the holding member 23.

In the first step, the holding member 23 for holding the closed end of the thin long tube 1 shrink-fits the thin long tube 1 when the thin long tube 1 is heated. The thin long tube 1 can be easily and surely held by utilizing the steps.

Next, the second step will be described.

The quenching basket 21 is lowered by an elevating device (not shown) as shown by the solid line arrow in FIG. 1, and is put into the quenching liquid stored in a liquid tank (not shown), and the quenching basket 21 is further lowered. As the quenching liquid, water, hot water, oil, an aqueous solution containing a polymer compound such as polyalkyl glycol, or the like is used.

As the quenching basket 21 descends, each holding member 23
, And each thin long tube 1 held and fixed to each holding member 23 descends in the quenching liquid.

Looking at the relationship between the thin long tube 1 and the holding member 23, the holding member 23 receives the downward force and pulls the thin long tube 1 downward. Therefore, the thin long tube 1 is pulled upright by the holding member 23 and descends in the quenching liquid. At this time, since the closed end of the thin long tube 1 is located on the lower side, buoyancy acts on the thin long tube 1 by the quenching liquid as shown by the broken line arrow in FIG.

The thin long tube 1 is provided vertically,
Furthermore, since the thin long tube 1 is held at the lower end by the holding member 23 and pulled downward, the buoyancy is reduced.
It acts as a force to extend straight in the vertical direction.

Therefore, the thin long tube 1 is rapidly cooled by the quenching liquid and cooled while the deformation such as bending and crushing is suppressed.

After cooling, the gap between the thin long tube 1 and the holding member 23 returns to the original gap, so that the thin long tube 1 can be easily removed.

As shown in FIG. 2, the holding members 23 are arranged in a staggered manner on the quenching basket 21 and the thin long tubes 1 are arranged in a staggered manner. It is possible to suppress the deformation of the thin long tube 1 by the flow of the strong quenching liquid without hindering the flow of the strong quenching liquid.

When the outer diameter of the thin long tube 1 is large and the holding member 23 does not hold it sufficiently, the holding member 23 is provided with a clamp mechanism 24 as shown in FIG. The thin long tube 1 is surely held by pressing.

Next, a specific example will be described.

First, the material is aluminum alloy A707.
It consists of 5 and has dimensions of 70 mm outer diameter x 2 mm wall thickness x 100 length
A thin long tube of 0 mm was targeted. The thin long tube was quenched by the conventional quenching method and the quenching method of the present invention using the holding member made of SS41.

As a result, in the conventional quenching method, the thin long tube is deformed by bending 1.0 mm and crushing 0.5 mm. On the other hand, in the quenching method of the present invention, only a very small deformation of 0.1 mm in bending and 0.03 mm in crushing occurred in the thin long tube.

Next, the material is aluminum alloy A2014
Consists of an outer diameter of 120 mm x wall thickness of 2 mm x length of 120
A thin long tube of 0 mm was targeted. The thin long tube was quenched by the conventional quenching method and the quenching method of the present invention using the holding member made of SS41.

As a result, in the conventional quenching method, the thin long tube is deformed by bending 1.2 mm and crushing 0.6 mm. On the other hand, in the quenching method of the present invention, only a very small deformation of 0.3 mm in bending and 0.05 mm in collapse occurred in the thin long tube.

The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways.

[0043]

As described above, according to the quenching method for a thin long tube having one end closed according to the present invention, when the thin long tube having one end closed is put into a quenching solution and rapidly cooled, It is possible to suppress the occurrence of deformation such as bending of the pipe, and therefore it is possible to perform good quenching.

Since the holding member for holding the closed end of the thin long tube is shrink-fitted to the thin long tube when the thin long tube is heated in the first step, it is easy to use the first step. In addition, the thin long tube can be reliably held.

[Brief description of drawings]

FIG. 1 is a view showing a state in which a thin long tube is inserted into a holding member in an embodiment of a quenching method of the present invention.

FIG. 2 is a view showing a quenching basket used in the embodiment.

FIG. 3 is a view showing a modified example of the holding member in the same embodiment.

FIG. 4 is a diagram illustrating a conventional quenching method.

[Explanation of symbols]

1 ... Thin long tube, 21 ... Quenching basket, 23 ... Holding member.

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[Procedure amendment]

[Submission date] December 22, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016] As the metal for forming the thin walled elongated tube 1 include, for example, an aluminum alloy. The wall thickness of the thin thin tube 1 is, for example, in the range of 0.1 to 10 mm.
Heat treatment type alloys are less than 0.1 mm, and less than 10 mm do not bend. Length is 300 mm or more, 300 mm
If it is less than, it does not bend much. The closed end of the thin long tube 1 is used as a bottom or a knot when using the thin long tube 1.

Claims (1)

[Claims] 1. A thin long tube made of metal and having one end closed is heated, and a coefficient of thermal expansion smaller than that of the metal forming the thin long tube is provided on the outer peripheral side of the closed end of the thin long tube. A first step of shrink-fitting a holding member made of a metal having the thin-walled long tube upright with the holding member facing downward, and applying a downward force to the holding member; A second step of immersing the thin long tube in a quenching liquid and descending to rapidly cool the thin long tube.