JPS6046817A - Manufacture of metallic pipe-shaped member - Google Patents

Abstract

PURPOSE:To manufacture a metallic pipe-shaped member whose dimension accuracy is good by heating as one body a pipe-shaped member and an arbor having a large coefficinet of thermal expansion, drawing out and contracting the pipe-shaped member by gravity of the arbor, and also expanding it in the horizontal direction by a thermal expansion of the arbor. CONSTITUTION:A pipe-shaped member 1 made of Al, etc. and an arbor 2 made of stainless steel, etc, having a larger coefficient of thermal expansion than siad member are formed as one boby, suspended by a suspending tool 4 of a supporting tool 3, put into an electric furnance 6 and heated, and metallic pipe-shaped member 1 is plastically deformed. Subsequently, this pipe-shaped member 1 is drawn out by the own gravity of the arbor 2 and contracted on the arbor 2. By continuing further the heating, the pipe-shaped member 1 is expanded in the horizontal direction up to a prescribed crossing dimension by a thermal expansion of the arbor 2. In that case, it is prevented by a limiter 5 to be drawn out excessively. Thereafter, the electric furnance 6 is cooled, the arbor 2 is taken out, and the metallic pipe-shaped member 1 whose dimension is adjusted with a high accuacy is obtained without damaging the inside wall.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for manufacturing a long metal tubular member with a relatively thin wall thickness, and in particular to a method for easily achieving a high degree of dimensional accuracy and stability. Regarding how it can be done.

[Background of the invention]

As a means of precisely manufacturing long cylindrical or square cylindrical tubes within narrow tolerances, a technology that thermally adjusts dimensions (th
(ermal sizing) is used. The feature of this method is that the force that adjusts the dimensions is the difference in thermal expansion between two types of materials; one of the materials is a hollow long tube, and the other material is a long tube. Six axes (
A material that can be formed into a mandrel shape and whose coefficient of thermal expansion is sufficiently larger than that of a long tube material is used.

A conventional example of such a method is shown below.

(1) J, N, 5uldan and RJ, Kra
hn ; sizingof Zircaloy 8t
ructurals, Feb, 1967゜WAPD-T
M-620 In this example, ductile cast iron (thermal expansion coefficient 13.68xlO-'/
1? ) and 5t JS304 stainless steel (18,36x1
Zircaloy-4 (approximately 6.48X
Thermal sizing of tubes or cans made of IO'''6/C) is carried out. Here, 5US304 stainless steel is thermally dimensioned at lower temperatures than required for six-shafts (mandrels) made of ductile cast iron. Used for dimension adjustment.In this example, Zircaloy-4 strips are adjusted to the specified dimensions ±0.
．． A semi-cylindrical shell with an inner diameter equal to the outer diameter of the mandrel used for mechanical grinding, welding and dimensioning of Zircaloy-4 tubes after forming into the required floating shape to a tolerance of 0.01 crn. form as. The strip is then attached to the mandrel and a T is placed along the two longitudinal seams.
IG welded and then using a mandrel to 482C to 7
Annealed in vacuum at a temperature of 88C and made of stainless steel. Dimensions are adjusted by annealing in vacuum at 11482C to 632C. After the mandrel has cooled, the tube thus formed is removed, inspected, and sized repeatedly as necessary.

(2) US Pat. No. 3,559,278 In this example, a metal sheet tubular body divided into parts is attached to a mandrel, butt welded, and then heated at a sufficiently high temperature and shaped. The dimensions of the mandrel are such that the tube has the required lateral dimensions during cooling.

(3) Japanese Patent Publication No. 57-56408 1'-Method for manufacturing a metal tubular member" This example uses a long metal tubular member, which has a considerably larger coefficient of thermal expansion than the member, and has a diameter smaller than that of the metal tubular member. In the method of manufacturing a metal tubular member, the metal tubular member and the six shafts are plastically deformed by heating both the metal tubular member and the six shafts. The two shafts are attached so that they can contract independently of each other, and while the metal tubular member and the six shafts are being heated, the metal tubular member is first stretched in the longitudinal direction by the expansion of the six shafts, causing it to contract into a centrifugal shape, and then The metal tubular member and the 6-shaft continue to be heated, and the stretched metal tubular member is expanded in the diametrical direction until it reaches a predetermined cross-sectional dimension due to the expansion of the 6-shaft, and then the 6-shaft and the metal tubular member are expanded. This method of manufacturing a metal tubular member is characterized by cooling the member and removing a number of metal tubular members from six axes. The purpose of this example is to
It is said that this can be achieved by improving the accuracy of one dimension adjustment while avoiding damage to the inner surface of the tube to be dimensioned, which may occur in the example of IX2), and this can be achieved by the method described above.

However, in the conventional example described above, the deformability is limited to the amount of plastic deformation due to the difference in thermal expansion between the metal tubular member and the six axes.

[Purpose of the invention]

An object of the present invention is to provide a method for accurately adjusting the dimensions of a metal tubular member, even in combinations where the dimensions cannot be adjusted due to the force due to the difference in thermal expansion between the tubular member and the six axes.

[Summary of the invention]

The present invention utilizes a thermal expansion difference between two types of materials.
alsiZing Niite improves the problem that there is a limit to the amount of plastic deformation depending on the combination of materials and the available temperature. By continuing to pull the other end of the tubular member, the dimensions of the tubular member are reliably adjusted. In this case, since the amount by which the tubular member is stretched is known in advance,
The desired purpose can be achieved by providing a limiter to prevent excessive stretching.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, 1 is an aluminum tubular member, 21
1 - 6 shafts (mandrel) made of SUS304 stainless steel, 3 is a support for hanging the combination of tubular member 1 and 6 shaft 2, 4 is a hanging tool, 5 is a limiter, and 56 is an electric furnace. It is.

The tubular member 1 is made by bending two aluminum strips into a U-shape and welding them together, and smoothing the weld bead using a planicher. Furthermore, an aluminum plate is welded to one end. The inner diameter of the tubular member is expanded by the thermal expansion of the 6-axis, and adjusted so as not to damage the inner surface of the tubular member at the stage of inserting the 6-axis' into the tubular member. The thickness of the aluminum plate used in this example was 0.8 ttrm. 6
The shaft 2 has a length of about 2 m and a rectangular cross section of 134 m+ on a side.

The six shafts and tubular member thus combined are inserted into a vertical electric furnace and heated in a vacuum. The heating temperature can be appropriately determined depending on the desired dimensions, the strength of the material, etc. In this example, the electric furnace was heated to 500C and held for about 3 hours, and then cooled down.

The material of the aluminum plate is A1050P tempering code 0 specified in JIS H4000, and has a yield strength of about 2.0 kg/mm2 at room temperature. At high temperatures, the yield strength decreases, the mandrel easily deforms due to its own gravity, and the thermal expansion of the mandrel allows for accurate dimensional adjustment.

In addition to the method described in this embodiment, the method of continuing to pull the tubular member while heating it can also be performed mechanically from outside the electric furnace.

〔Effect of the invention〕

According to the present invention, when adjusting the size of a metal tubular member, even in combinations where the size cannot be adjusted due to the force due to the difference in thermal expansion between the tubular member and the six axes, the tubular member can be stretched in the axial direction. Shaping can be done with precision.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention. 1... Tubular member 42... 6 shafts, 3... Support, 4
...Hanging tool, 5...Limiter-16...Electric furnace. Agent Patent Attorney Akio Takahashi

Claims (1)

[Claims] 1. Heat the tubular member and the 6 shafts having a higher coefficient of thermal expansion as one body, stretch the tubular member and contract it into a thin shape, and at the same time expand it laterally to a predetermined transverse dimension by the 6 shafts, A method for manufacturing a metal tubular member that obtains a predetermined finished dimension, the method comprising using six axes of gravity as a means for stretching the tubular member.