JPS6384829A - Manufacture of self-fastening cover member - Google Patents

Abstract

PURPOSE:To make it possible to manufacture a self-fastening type cover member such as a highly durable pipe or the like, by applying a difference in temperature between a pipe-like thin sheet having a certain inner peripheral length including an interference and an inner member, and by fitting the pipe-like thin sheet onto the inner member before the temperature thereof is returned to a normal temperature. CONSTITUTION:A steel pipe having, for example, an outer diameter of, for example, 1,000mmphi is used as an inner member, and a SUS304 steel plate having a thickness of 1mm is used as an outer member 3, which has a cylindrical shape having an inner diameter slightly less than the outer diameter of the inner member 1 by 0.1mm. The outer member is heated by a heater 5, and then is lifted up by a crane through the intermediary of a sling 4. Further, the outer member 3 is fitted from above onto the inner member 1 attached with a jig 2, and is cooled. An extension in the outer peripheral length of the outer member 3 at 400 deg.C due to thermal expansion is about 22mm while a radial gap thereof with respect to the inner member is about 3.4mm, and after cooling the circumferential fastening force is about 12kg/mm<2>.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a member used for corrosion-resistant steel pipe piles, steel pipe columns of subway station buildings, and others, the outer surface of which is coated with a thin plate that has self-tightening properties. Relating to a manufacturing method.

[Conventional technology]

Corrosion-resistant steel pipe piles used for piers, etc., and steel pipe columns often used for underground station buildings, are coated with paint, coated with synthetic resin film, or made of stainless steel to ensure corrosion resistance, durability, and design. It is covered with a coating, and various methods for applying the coating have been developed.

However, none of these conventional coatings are perfect, with paint and synthetic resin coatings having poor impact resistance, and stainless steel outer linings having problems such as poor adhesion to inner components. .

As a material with good adhesion, it is possible to form a clad steel plate into a tubular shape or to use overlay welded steel, but these processes are complicated and the manufacturing cost is high, and A
Depending on the type of sheathing material, such as aluminum alloy, it may be difficult to join it to the inner member.

It has been known since ancient times to fix a thick ring-shaped or cylindrical member to the outer diameter of a shaft, rim, cylinder, etc. by shrink fitting, but in this case, the inner diameter of the outer member to be shrink-fitted and the inner The outer diameter of the member must be precisely adjusted by machining, and the surfaces to be shrink-fitted are limited to circular cross-sections.

Various techniques for manufacturing double pipes have also been developed.

For example, JP-A-55-117514.55-117515
．． 55-117516, but both of these apply a temperature difference between the inner and outer tubes before and after layering the inner and outer tubes, then apply pressure to the inner tube to expand it, then eliminate the temperature difference and tightly fasten the inner and outer tubes. In this method, the inside of the tube is lined with a thin corrosion-resistant member. These require a process of applying pressure to the inner tube, which not only complicates the process but also requires high-pressure equipment if the inner tube is thick.

Furthermore, Japanese Patent Laid-Open No. 59-83870 discloses a method for lining a pressure vessel. This technique is a pressure vessel lining method in which a cylindrical lining is formed on a split jig, an outer shell whose inner surface has been previously machined is shrink-fitted to the cylindrical lining, and then the split jig is removed. This method requires machining of the inner surface of the outer shell and is limited to members with a perfectly circular cross section.

[Problems to be Solved by the Invention] Unlike the prior art described above, the present invention aims to provide a simple method for tightly covering the outer surface of an inner member with a thin plate, and achieves the first object.

■ Fit a thin plate such as a thin stainless steel plate onto the outer surface of a steel pipe, etc. while maintaining tightness.

■ Not only circular cross-sections, but also oval and polygonal cross-sections can be constructed.

■ The material of the inner member to be coated can be applied to materials other than metal, such as wood and concrete.

[Means for solving problems]

The technical means of the method of the present invention to achieve this purpose are as follows.

b) Manufacture a tubular thin plate whose dimensions are adjusted to the inner circumference length with a tightening allowance added to the outer circumference length of the cross section of the inner member.

口) Provides a temperature difference between the tubular thin plate and the inner member.

For example, uniform heating of the tubular sheet or cooling of the inner member or a combination of both may be used. The heating temperature and cooling temperature are determined by the type of material of the tubular thin plate and the inner member, the cross-sectional dimensions of the product, etc., and the temperature difference between the tubular thin plate and the inner member may be about 200 to 400°C.

c) Fitting the tubular thin plate onto the inner member. This operation is easy because the tubular thin plate and the inner member have a dimensional difference due to thermal expansion or contraction due to the temperature difference.

2) Then return to room temperature. The contraction of the tubular sheet and/or the expansion of the inner member creates a self-tightening effect between the tubular sheet and the inner member, causing the tubular sheet to fit over the outer diameter of the inner member as an outer covering.

[Effect]

The present invention precisely adjusts the inner circumferential length of the tubular thin plate to be coated with respect to the outer circumferential length of the inner member, and utilizes expansion and contraction to cover the outer surface of the inner member with a thin plate coating material such as stainless steel or aluminum alloy. This is a self-adhesive covering.

The inner circumferential length of the tubular thin plate serving as the outer covering is determined by adding a tightening allowance to the outer circumferential length of the inner member. This interference should be as small as possible and below the elongation rate within the elastic limit range of the material of the outer tubular thin plate (0.20% in the case of steel), which remains in the thin tubular plate when it undergoes self-tensioning contraction. This is to minimize residual stress, which can be a problem.

However, depending on the purpose of use which does not require such consideration, there is no problem as long as the interference is within the range of uniform elongation of the material of the thin plate.

The following will explain the case of heating a tubular thin plate as an example. The tubular thin plate is uniformly heated to 200 to 400°C to thermally expand it,
Fits onto the inner member. During this external fitting, there is a loose fitting state with a gap between the inner member and the inner member. Thereafter, the outer member (tubular thin plate) is allowed to cool naturally, so that the outer member (tubular thin plate) contracts and is crimped onto the inner member surface. The thickness of the outer covering material is determined depending on the dimensions of the product member, the intended use, etc. (for example, 0.5 to 2 mm).

In the method of the present invention, of course, when the inner member has a circular cross section,
If the roundness is not good, elliptical cross section, polygonal cross section, or other irregular cross sections have no recesses, construction can be performed even if the cross section is irregular.Since the outer member is a thin plate and is naturally cooled, the outer surface of the inner member It blends well and adheres well.

The material of the inner member may be a material other than metal, such as wood, concrete, or plastic, and is not limited as long as it is heat resistant within the heating temperature range of the outer member.

Next, the case of cooling the inner member will be explained. If it is not desirable to heat the tubular thin plate from a design or other point of view, if a cold source is easily available such as in a liquefied gas handling facility, or if the inner member is made of a material with a large amount of heat shrinkage, the inner member may not be heated. By cooling, the tubular thin plate can be tightly fitted onto the inner member. Moreover, it is of course possible to use heating and cooling in combination depending on the case.

〔Example〕

FIG. 1 shows a schematic diagram showing an embodiment of the present invention, and FIG.
1(a) is a longitudinal cross-sectional view showing the heating process of the outer member (tubular thin plate) 3, FIG. 1(b) is a cross-sectional view thereof, and FIG. 1(e) is a side view of the inner member standing up.

A steel pipe with an outer diameter of 1000 mmφ is used as the inner member 1, and 5US304. Using stainless steel with a thickness of inn, the inner diameter of the outer member 3 is formed into a cylindrical shape whose inner diameter is Inm (0.1%) smaller than the outer diameter of the inner member l, as shown in Fig. 1(a). The temperature was raised to 400°C by heater 5,
Next, it was lifted up by a crane via the hanging tool 4, fitted from above onto the inner member 1 equipped with the insertion jig 2, and left to cool.

The circumferential extension of the outer member 3 at 400° C. due to thermal expansion is approximately 22 mm, and the radial gap with the inner member is 3.4 mm.
mm, and the circumferential tightening force of the outer member after cooling was 12 kg/mrrr'.

FIG. 2 shows another embodiment, in which an insertion flange 6 is attached to the outer member (thin tubular plate) 3, heated uniformly by a heater 5, and the inner member 1 is pushed and inserted in a horizontal position. Suitable for manufacturing long parts. The flange 6 will be cut off later.

〔Effect of the invention〕

The present invention has the following effects.

(1) It is possible to easily manufacture self-tightening covering members such as piles, pipes, columns, etc., which have an outer covering tightly attached to the outer surface of the inner member and are highly corrosion resistant and durable.

(2) It is cheaper than clad steel plates or tactile welding. In addition, with clad steel plates, it is not possible to cover only a portion, but with the method of the present invention, it is possible to cover only the most necessary portions. The splash zone can be provided with an outer lining according to the invention, which has the advantages of corrosion resistance, stability, high reliability and low cost.

(3) Conventional polyethylene coatings had problems with damage and tearing due to collisions and other causes, but since the method of the present invention uses stainless steel etc., there is no risk of damage or tearing, and it can be used, for example, in places with drift ice. It can also be used for piles, etc., and has high reliability and long life.

(4) In the method of the present invention, the inner member is not limited to a circular cross section, but can be oval if it has a convex cross section.

It can be applied to various cross sections such as oval, polygonal, etc.

(5) The inner member can also be made of materials other than metal.

(6) It can be constructed easily and inexpensively without requiring special equipment or complicated processes.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the method of the present invention, and FIG. 2 is a schematic diagram of another embodiment. l... Inner member 2... Insertion jig 3... Outer member (tubular thin plate) 4... Hanging tool 5... Heater 6... Flange

Claims (1)

[Claims] 1. Manufacture a tubular thin plate having an inner circumferential length that is equal to the outer circumferential length of the cross section of the inner member, apply a temperature difference between the tubular thin plate and the inner member, and attach the tubular thin plate to the inner member. A method for producing a self-adhesive covering member, characterized by fitting the member and returning it to room temperature.