JPS6262078A - Abrasion-resistant lining double pipe and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technique belongs to the field of manufacturing technology for a wear-resistant double pipe in which an outer pipe and a wear-resistant inner pipe made of ceramic or the like are tightly connected.

<Summary of the gist> The invention of this application is to improve the abrasion resistance of piping used for slurry transportation, pneumatic transportation, etc., in which an outer pipe and an abrasion-resistant inner pipe are relatively layered. A raw pipe such as a heavy pipe is subjected to circumferential annular heating after cooling the former stage by relatively moving a circumferential annular heating means such as high-frequency induction heating and cooling means such as water in the front and rear stages in the axial direction, and This invention relates to a wear-resistant double tube in which the inner tube is tightened by the outer tube after cooling in a subsequent stage, and the method for manufacturing the same. The inner tube is lined with segment-shaped pieces of wear-resistant material such as ceramics, etc., adjacent to each other, and when performing annular heating of the outer tube and cooling before and after it, the expansion diameter due to thermal expansion of the heated portion is adjusted to the surrounding low-temperature portion. After cooling, the diameter of the heated portion is made smaller than the initial diameter by annular heating and cooling so that the outer tube tightens the inner tube, thereby creating a strong bond. This invention relates to a wear-resistant inner-lined double pipe with sufficient fitting allowance and a method for manufacturing the same.

<Prior Art> As is well known, piping is widely used for transporting fluids in various industrial fields. In ball slurry transport pipes, or air transport pipes containing powder particles such as $9J dust and silica sand, there is a problem in that the inner surface of the pipe is easily worn out.

This kind of piping usually uses inexpensive steel pipes such as gas pipes, and when they wear out, they are replaced with new pipes or welded backing plates to the worn parts.

<Problems to be Solved by the Invention> However, in piping for applications where wear resistance is particularly required, pipes made of materials with excellent wear resistance such as high chromium cast iron are sometimes used.

By the way, in general, the +S wear resistance of steel materials has a good correlation with hardness, and materials with excellent wear resistance are uniformly extremely hard.

For example, 27Qr cast iron, which is often used as a wear-resistant material, has a hardness of 81 or higher on the Shore hardness scale.

However, on the other hand, as the hardness increases, the toughness of the steel material tends to decrease, and pipes made of wear-resistant materials such as the above-mentioned high chromium cast iron have the disadvantage of being susceptible to breakage when subjected to impact force.

In addition, since high-hardness wear-resistant materials have extremely poor weldability and workability, the first disadvantage is that it is impossible to attach the 7 langes to the main body by welding, and the second disadvantage is that it is impossible to attach the 7 langes to the main body by welding. Even when it is formed, it is difficult to finish and drill holes, and thirdly, repair welding is difficult.

In addition, it also has the disadvantage of high manufacturing costs.

For this reason, so-called clad steel pipes, which are steel pipes lined with a wear-resistant material, have come into use.

This type of clad steel pipe is usually made by centrifugal casting or overlay welding, and the lining is metallurgically joined to the pipe body.

Since the inner surface of the clad steel pipe is covered with a wear-resistant material, the wear resistance of the clad steel pipe is far superior to that of a normal single-layer steel pipe made of a material that does not take wear resistance into consideration.

Further, since the inner tube body does not need to be provided with a wear-resistant material, a material having sufficient toughness and good weldability can be used.

Therefore, unlike a pipe made only of wear-resistant material, it has sufficient impact resistance, and it is also possible to form the flange separately and attach it by welding.

However, clad steel pipes have the disadvantage that they tend to crack because tensile stress remains in the lining regardless of the manufacturing method.

Another drawback is that once a crack occurs, the crack can easily propagate to the tube body, resulting in a through crack, since the inner tube is metallurgically joined to the outer tube.

Therefore, we developed a double-layered tube consisting of an outer tube with sufficient toughness for practical use and an inner tube with excellent abrasion resistance.The two tubes are not metallurgically connected, but are in contact with each other at a certain pressure. It is desired to develop a self-containing double pipe in which the inner pipe is placed in a compressive stress state.

This is because such a self-consolidated double pipe has the same advantages as a clad steel pipe, and also eliminates the above-mentioned drawbacks of the clad steel pipe.

By the way, the conventional self-tightening double-pipe manufacturing techniques include firstly the shrink fitting method, secondly the pipe expansion method, and thirdly the heat-expanding method. Each of these methods has disadvantages.

First, the first method requires strict machining accuracy on the inner diameter of the outer tube and the outer diameter of the inner tube, but in the case of a double-walled tube with internal wear resistance,
Since the inner tube is made of a wear-resistant material with poor machinability, it is very difficult to perform the required machining.

In addition, this method generally makes it extremely difficult to fit long tubes.

In addition, in both the second and third methods, the inner tube is expanded plastically, but in this case, the strength (yield point) of the inner tube is extremely high, and the inner tube has a higher strength than a corrosion-resistant double tube. Since it becomes somewhat thick, extremely high pressure for expansion is required, which is not practical.

In particular, with the second method, in the case of double-walled pipes where the strength (yield point) of the outer pipe is higher than that of the inner pipe, even if the inner pipe is expanded plastically, the difference in elastic return causes the difference between the inner and outer pipes. A gap is created in between.

In order to deal with this problem, in the invention of Japanese Patent Application No. 122663/1986, which is the applicant's earlier invention, the outer tube and the inner tube are layered relatively to each other to form a blank tube, and an annular TJr+heating means is provided on the outside of the outer tube. Furthermore, by providing a cooling means such as a water shower before and after the cooling means and moving these means and the mother pipe relative to each other in the axial direction, the diameter of the outer pipe is expanded by the annular heating means, and the cooling before and after that is carried out. A new method that skillfully obtains a self-tensioning double tube by constraining the expansion diameter by a means to yield the outer tube, giving a large diameter reduction by cooling contraction, and tightening the outer tube against the inner tube. We have developed a new double tube manufacturing technology.

On the other hand, recent material development research has led to the emergence of new materials such as ceramics, which have high strength and excellent wear resistance, and are now available for mass production. Techniques have been developed to attach them using adhesives.

However, this type of technology has the problem of peeling of the ceramic pieces inside the piping used, and even if the inner pipe made of ceramics is relatively heavily mounted on the outer pipe, it is extremely difficult both technically and cost-wise. There is the inconvenience of being strange.

As described above, although there is a strong need for wear-resistant double pipes, the conventional technology has not been able to provide wear-resistant double pipes that meet the practical requirements.

The purpose of the invention of this application is to solve the nine problems of double tube manufacturing based on the above-mentioned prior art as a technical problem, and to solve the above-mentioned technical problem of manufacturing double tubes by using a wear-resistant material such as ceramics for the outer tube in a large number of segment-shaped or arch-shaped pieces. The inner tube is placed adjacent to the inner tube, and this is inserted relatively loosely into the outer tube.The outer tube of the layered blank tube is heated in the circumferential direction and the front and rear peripheral areas are cooled simultaneously and continuously in the axial direction, for example. By applying heating and cooling while moving relative to each other in the axial direction, the diameter of the outer tube is reduced and the inner tube is tightened by the outer tube. It is an object of the present invention to provide a stretched double pipe and a method for manufacturing the same.

In order to solve the above-mentioned problems, the structure of the invention of this application, which is based on the above-mentioned claims, is to solve the above-mentioned problems by providing a large number of segments of the outer tube and the wear-resistant material. Inner tubes consisting of shaped, arched, etc. pieces are layered relative to each other to form a blank tube, and when reducing the diameter of the outer tube of the blank tube, annular heating is applied to the outer tube, and circumferential annular heating means and cooling are applied. The means and the raw pipe are moved relative to each other in the axial direction over time, and at this time, the front of the annular heating means and
By providing a cooling means at the rear, the presser bending moment in the radial direction toward the center acts continuously in the longitudinal direction at the front and rear of the heated portion when viewed from the axial length, The expanding diameter of the heated part of the outer tube is constrained by the peripheral cooling part to yield, and then the inner tube is tightened so that the diameter is reduced from the initial diameter by cooling contraction, and each piece of wear-resistant material is mechanically bonded to each other. A technical measure has been taken to firmly abut and fix the two parts to each other.

<Embodiments - Configuration> Next, embodiments of the invention of this application will be described as follows based on the drawings.

The illustrated embodiment is a wear-resistant lined double pipe such as a slurry transport pipe having an inner pipe made of ceramics, and its manufacturing mode. In addition, as the inner tube 2, short cylindrical segment-shaped pieces 2', 2', made of alumina ceramics, which have high wear resistance and high hardness, are used. Then, the outer tube 1 and the inner tube 2 are appropriately loosely inserted relative to each other in a state in which they are axially adjacent to each other to a set length and are completely cooled to form a double-pipe blank tube 3.

First, an embodiment of the method for manufacturing a wear-resistant lined double pipe according to the invention of this application will be explained with reference to FIGS. It is set to move at a predetermined speed in the axial direction as shown by the arrow, and furthermore, as shown in FIG.
For example, a high-frequency induction heating device @ 4 (hereinafter referred to as heating device) is set, and a cooling device for an annular shower device, such as a water passage, is placed near the heating device 4 at a predetermined distance in the front and back of the axis. Set 5.5 and make 1 unit ()
By moving the double tube blank tube 3 in the direction of the arrow, one unit of the heating device 4 and the cooling device 51.5 is moved relative to the double tube blank tube 3.

Therefore, when the double tube material tube 3 is relatively moved at a predetermined speed,
The heating device 4 applies an expansion effect due to heating to the cooling of the outer tube 1 by the cooling devices 5.5 before and after it, but in this process, as schematically shown in FIG. is in the cooling part.

On the other hand, if it is a free end, it will freely expand in diameter and protrude in the circumferential direction, as shown in Fig. 3, but in reality, the heating part has its expansion diameter restricted by the cooling part at both ends. As a result, a ring-shaped curved plastically deformed portion is formed. This process is carried out independently of the ring-shaped pieces 2' of each segment that constitute the inner tube 2.

Then, as the double tube blank tube 3 moves relatively in the direction of the arrow, the outer tube 1 is heated by the heating device 4 and plastically deformed.
When the part passes through the heating part and is cooled by the cooling means, it contracts as shown in Fig. 6 and conversely becomes smaller in diameter to a greater extent than the initial diameter, so that a large fitting allowance is obtained and the outer tube 1 is tube 2
(The ring-shaped piece 2' of each segment) is tightened by a tightening action.

Since the action of this one unit acts on all circumferential portions of the outer tube 1, by continuously moving the base tube 3 relative to each other in the axial direction, all portions of the outer tube 1 are reduced in diameter, A binding state is created over the entire length of the inner tube 2 over the entire length of the tube 3, and as a result, a wear-resistant inner-lined double tube 6 of a self-stressing double tube as shown in FIG. 1 is formed. Ru.

The above-mentioned tightening process is performed regardless of the wall thickness of the inner tube 2, that is, the ring-shaped piece 2' of each ceramic cement, and regardless of the axial length of the metal heavy pipe material tube 3.
Furthermore, since the process is performed in a manner that has almost no relation to the accuracy of the joint surfaces between the outer tube 1 and the inner tube 2, the wall thickness of the inner tube 2 (piece 2' of each segment) is large. Moreover, it is extremely effective in manufacturing the wear-resistant lined double pipe 6 which is a long pipe.

In the embodiment described above, the inner tube 2 made of ceramic has a large number of ring-shaped pieces 2', 2', etc. of segments arranged in the axial direction, but as shown in FIG. The arch-shaped so-called Yatsuhashi-shaped piece 2', 2
An embodiment in which a large number of ``...'' are adjacent to each other in the circumferential direction and the axial direction is also possible, and in any case, the inner tube 2 is mechanically restrained by the tightening action of the outer tube 1 and the inner tube has a circular cross section. 2
can be configured.

Therefore, the compressive stress in the circumferential direction and the axial direction of the inner tube 2 acts strongly, and the mutual sealing between the pieces 2', 2', . . . works strongly, and no leakage of the working fluid occurs.

According to experiments, when one unit is moved relative to the blank tube 3 in the above embodiment, when the blank tube 3 is a long tube, as described above, in one pass by one unit, the outer tube 1 When the diameter is 100φ and the wall thickness is 4t, the diameter is reduced by about 0.5M in one pass.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments, and the inner tube may be made of a double-walled tube lined with a special Teflon-processable wear-resistant material other than ceramics, or the manufacture thereof. Various embodiments can be adopted, such as a double pipe using a corrosion-resistant material for the inner pipe and a method for manufacturing the same.

Moreover, it is applicable not only to straight pipes but also to curved pipes such as bent pipes.

Note that the invention of this application differs from the conventional circumferential diameter increasing/reducing means by means of applying linear heating or cooling means in the direction of movement. The diameter is reduced by being restrained by the adjacent cooling part, and the diameter of the heating part is reduced after cooling. For example, when manufacturing a double pipe, the outer pipe is tightly connected to the inner pipe. The mechanism is completely different.

<Effects of the Invention> As described above, the invention of this application basically provides a wear-resistant lined pipe that is welded and tightly connected to the inner surface of the outer pipe in a pure lined double pipe such as a slurry transport pipe. Because the pipes are mechanically connected and abutted to each other by short tubular segments or many arch-shaped pieces, it is difficult to manufacture long pipes, so it is possible to form a pipe lined with ceramics or other material into a considerably long length. Moreover, it has the excellent effect of being able to easily carry out the initial loading of relatively overlapping inner and outer tubes.

In addition, since each piece is fastened together by tightening the outer tube, it is mechanically stable and has the excellent effect that peeling does not occur during operation.

In addition, since each piece receives compressive stress due to tightening due to the outer tube, corrosion resistance is improved, and the sealing performance between each piece is improved, preventing leakage of working fluid and improving durability. be done.

Therefore, when manufacturing wear-resistant inner-lined double pipes, etc., the diameter of the outer pipe can be reduced, and the elastic return difference based on the difference in yield point between the outer pipe and the inner pipe can be used, as in the case of hydraulic pipe expansion. There is no risk of gaps occurring, and the excellent effect of obtaining piping with extremely high accuracy as a self-contained double pipe is also achieved.In addition, there is no need for the enormous pressure required for pipe expansion, and the power cost during production is reduced. It has the effect of being cheap and can be manufactured at low cost.

In addition, unlike conventional shrink fitting, etc., the accuracy of the joint surface between the outer tube and the inner tube is not required to be so high, and therefore, as mentioned above, it has the excellent effect of being able to freely manufacture long tubes, etc. Ru.

In addition, the inner tube is highly wear resistant like ceramics,
Even if the outer tube has high toughness, the diameter can be reduced without any restrictions on the degree of freedom in design, and therefore the material selection for the outer tube and the inner tube can be freely selected.

Furthermore, an excellent effect is achieved in that a uniform fitting margin can be obtained not only in the circumferential direction but also in the longitudinal direction, and a highly accurate double pipe can be obtained.

Therefore, the degree of freedom in design is increased without being restricted by the length of the double pipe, and it is possible to manufacture the double pipe as desired.

[Brief explanation of drawings]

The drawings are schematic explanatory diagrams of embodiments of the invention of this application, and FIG. 1 is a partially cutaway schematic explanatory diagram of one embodiment, FIG. 2 is a perspective view corresponding to FIG. 1 of another embodiment, and FIG. The figure is a partial cross-sectional side view of the outer tube and the inner tube when they are stacked relative to each other, Figure 4 is a partial cross-sectional view of the mechanism for applying presser bending moment due to heating, and Figure 5 is a partial cross-sectional view of the mechanism for applying presser bending moment due to cooling. The perspective view and FIG. 6 are cross-sectional views of a double-walled pipe that has been reduced in diameter and self-tightened. 1... Outer tube, 2... Inner tube, 2', 2' piece, 3... Base tube, 4... Heating device, 5... Cooling device 6.6'... Wear resistance Diagram 1 of double lining pipe

Claims (2)

[Claims] (1) In a double pipe with wear-resistant material lined on the inner surface of the outer pipe,
A wear-resistant inner-lined double pipe characterized in that a large number of pieces of wear-resistant material are in contact with each other on the inner surface of the outer pipe and are tightened to form a lined pipe. (2) The outer tube is lined with a large number of pieces of wear-resistant materials to form an inner tube, and the outer tube is made into a blank tube by relatively layering, and the outer tube is heated annularly in the circumferential direction and cooled around it at the same time. The thermal expansion of the heated part is restrained by the low temperature parts on both the front and back sides of the heated part to suppress the expansion diameter, and then the heated part is contracted by cooling so that the diameter of that part becomes smaller than the initial diameter. Manufacture of a wear-resistant inner-lined double pipe characterized in that the pipe and the heating/cooling means are moved relative to each other in the axial direction so that the diameter of the outer pipe after cooling is smaller than the initial diameter over the entire length of the heating section. Method.