JPH0199781A - Manufacture of pipe interior build-up clad pipe - 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 present invention relates to a method for manufacturing a clad pipe with a built-in inner surface, and in particular, a method for producing a clad pipe with a small inner diameter by using a core member made of a small-diameter pipe or the like. The present invention relates to a manufacturing method useful for manufacturing.

[Prior Art] Conventionally, overlay welding on the inner surface of a tube is performed by inserting a welding torch smaller than the inner diameter of the tube along the inner surface of the tube.

[Problems to be Solved by the Invention] In the conventional manufacturing method described above, there is no particular problem in manufacturing a clad pipe using this method for large diameter pipes of 300 mm or more. However, for small-diameter pipes with an inner diameter of 80+U or less, the welding torch becomes complicated and it is difficult to miniaturize the welding torch. However, the reality is that it is not possible to manufacture clad pipes using such conventional manufacturing methods with pipes as small as 14 mm in diameter.

The present invention has been made in view of the above aspects,
It is an object of the present invention to provide a manufacturing method that enables YJ manufacturing of a cladding pipe with a small internal diameter even if a small diameter pipe or the like is used.

[Means for Solving the Problems] The method of manufacturing a clad pipe with built-up cladding on the inner surface of a pipe according to the present invention includes a first step of welding a cladding material to the outer surface of a metal core member, and The method is characterized by comprising a second step of removing the core member.

In the first step, the cladding material is overlay welded to form an overlay inner layer, and then a pipe outer surface layer forming material is overlay welded to the outer surface of the overlay inner layer to form an overlay outer layer; Thereafter, a second step can be carried out to produce a clad pipe consisting of a built-up inner surface layer and a built-up outer surface layer formed on the outer surface of the built-up inner surface layer. Meat this clad material again! & The part to be welded may be the entire outer surface of the core member, or may be a part of the outer surface.

A tube or a round rod can be used as the core member.

Among these, it is preferable to use a tube in order to reduce the amount of cutting. The inner diameter, outer diameter, length, cross-sectional shape, etc. of this core member are variously selected depending on the purpose and use. When using a tube as the core member, it is possible to use a tube with a small diameter that cannot accommodate a special small torch that is usually used, or it is also possible to use a rod-shaped body that cannot be used at all in a normal method. Further, the material of the core member used is not particularly limited, and since it will be removed by cutting or the like in the second step, it is preferable to use a material with as good workability as possible (for example, carbon steel, etc.).

As the cladding material, various materials can be used depending on the purpose and use. Usually, from the point of view of the additional i value of the pipe inner surface cladding pipe, C
O-based alloys are often used. Various welding methods can be used to perform overlay welding of the cladding material. This welding method includes powder plasma method, TI
The G method, the covered arc method, the MIG method, etc. can be used. The powder plasma method uses a tungsten electrode (-) with a good cooling effect as an electrode, and uses plasma arc heat to melt and weld powders such as stellite, colmonoy, and ceramic composite powder onto the surface of the workpiece. This is the way to do it. The TIG method is an inert gas arc welding method using a tungsten electrode. The coated arc method is an arc welding method that uses a coated arc welding rod. M
The IG method is a metal arc welding method that uses an inert gas such as argon as a shielding gas. Depending on the material used, it is desirable to select a welding method that causes as little penetration of welding from the clad material to the carbon steel as possible. This is to reduce the influence of dilution from carbon steel.

In addition, in the case of forming the built-up outer surface layer in the above-mentioned first step, various materials can be used as the tube outer surface layer forming material constituting this built-up outer surface layer depending on the purpose and use. For example, carbon steel, light alloy steel, stainless steel, etc. can be used as the tube outer surface forming material. In this case, the same material as the cladding material can be used for overlay welding up to the dimensions of the outer surface of the tube.

However, this clad material is usually expensive, so
From an economic point of view, inexpensive materials such as carbon steel or stainless steel are generally used. Further, the portion to which the material for forming the tube outer surface layer is welded may be any desired portion, and may be the entire outer surface of the inner surface layer, or a portion thereof.

The second step is a step of removing the rod-shaped core portion.

Cutting or the like can be used as a method for this removal.

Usually, in this second step, after the build-up welding in the first step, it is preferable to remove sufficient stress by a method such as stress annealing, and then remove the core member. This is to prevent scraping etc. due to residual stress. In this removal, processing is performed so that the cladding overlay welding layer is exposed on the inner surface of the tube.

Furthermore, if necessary, the outer surface of the tube is finished to a predetermined dimension to produce a clad tube with overlays on the inner surface of the tube.

[Example] The present invention will be explained below using specific examples.

(Example 1) First, in this example, a welding method with a small penetration rate from the core member was investigated. This is done in order to reduce the effect of dilution from the carbon steel to be used in this example.
This is because it is desirable to select a welding method that causes as little penetration as possible.

Here, a tubular body (inner diameter 20I) made of carbon steel is used as a core member.
III11 Outer diameter 38Ill11 Length 120001+11
).

As shown in Table 1, welding methods include powder plasma method, TIG (rod) method, covered arc method, TIG
(wire) method and IVlrG (wire) method were each used. Each welding condition was as follows. In this powder plasma method, the voltage was 150A and 128V. In the TIG (rod) method, the voltage was 25OA and 13V. In the covered arc method, 14. OA was set at 15 ■. In the TIG (wire) method, 20OA.

It was set to 11V. MIG ('fit'-) method, 2°O
A. It was set to 30V. Naori rad build-up thickness is 3++ each
v, and each was treated as one skin. Table 1 shows the results of the penetration rate from the cladding material to the carbon steel.

This penetration rate was calculated from the cross-sectional shape. Table 1 shows the hardness of the built-up part in each method.

According to the results in Table 1, the TIG method, MIG method, and shielded arc method have relatively large weld penetration rates compared to the powder plasma method, so at least two layers of overlay welding are required. Become. On the other hand, the powder plasma method has a significantly low melt penetration rate. Therefore, if this powder plasma method is used, predetermined properties can be sufficiently maintained even with one layer of overlay welding. From the above, the powder plasma method is the most suitable method for overlaying the cladding material onto the carbon steel core member.

(Example 2) As discussed in Example 1 above, since the powder plasma method is the most suitable overlay welding method for cladding materials, this example uses this powder plasma welding method to weld the cladding material. This is made by overlay welding of materials. The wJ manufacturing method of this embodiment is shown in FIGS. 1 to 8.

1a Table 2 (medium: m) First, the tubular core member 1 shown in FIGS. 1 and 2 is prepared. The material of this core member 1 is carbon steel, and the inner diameter is 20 m.
m, and an outer diameter of 38 cm. Furthermore, the length of the tube was set to 1200+m due to the internal cutting process.

Using this core member 1, as shown in Table 2, No.

Tests shown in Nos. 1 to 4 were conducted.

Then, overlay welding was performed on the middle part of the outer surface of the rod-shaped core member excluding both ends using the cladding material shown in Table 2,
As shown in FIGS. 3 and 4, a tube was manufactured in which a built-up inner layer 2 was formed on the outer surface of a core member 1. "Stellite 12" or rHXJ was used as this cladding material. This "Stellite 12" is a CO-based alloy,
is a chromium-nickel alloy. The welding method in this case was the powder plasma method as described above. In all cases, the welding conditions were 150Δ, voltage 26V, and 100% argon as the shielding gas.

The build-up layer of the cladding material is one layer, the thickness of which is 3.3 to 3.4 mm as shown in Table 2, and its quality is 1000!11-.

Next, as shown in FIGS. 5 and 6, an overlay outer layer 3 is overlay-welded to the entire outer surface of the overlay inner layer 2 formed as described above, and a part of the outer surface of the core member 1 is overlaid. A pipe was manufactured in which a built-up inner surface layer 2 was formed with a built-up outer surface layer 3 on the entire outer surface of the built-up inner surface layer 2. In this case, Sudenreth I (rER3091, 2J) was used as the tube outer surface layer forming material. This welding method is the MIG (wire) method. This welding condition is a current of 2
0OA, voltage 30V and shielding gas argon 98
% and 2% oxygen were used. The total number of overlays and their thickness are 4 to 6, respectively, as shown in Table 2.
M, and the thickness was 12.8 to 18.4 m1N.

Next, the tubular core member 1 of the tube shown in FIGS. 5 and 6
is removed to expose the inner surface of the built-up inner layer, and as shown in FIGS. 7 and 8, the built-up inner layer 2 and the built-up outer layer 3 formed on the entire outer surface of A clad pipe made of The finished pipe 4FA of this clad pipe is shown in Table 2.

According to this, the inner diameter of the pipe is 40111. The inner surface build-up layer has a thickness of 2.3 to 2.4 mm, an outer diameter of 5 Q mm or 80 mm, and a length of 11000 I1.

By the above manufacturing method, it was possible to easily manufacture a small rad tube with an inner diameter of 4Qlim. In addition, all clad materials have excellent corrosion resistance, heat resistance, and abrasion resistance, so this clad pipe has good durability against corrosion, etc. Also, since carbon steel is used as the tubular core member, it has good machinability and is easy to work with. In addition, since the powder plasma method was used to remove the cladding material TtF1 welding, there was less weld penetration.
・) It was possible to maintain the specified properties even during overlay welding. Furthermore, since the MrG welding method was used to form the overlay outer layer, welding efficiency was high and workability was good.

[Effect of re-lighting] The method for producing a clad pipe with built-up cladding on the inner surface of a tube according to the present invention is characterized in that a cladding material is welded overlay on the outer surface of a metal core member, and then this core member is removed. Therefore, according to this manufacturing method, the core member can be used whether it is a small diameter pipe or a rod-shaped material, and therefore even a clad pipe with a small inner diameter can be easily manufactured.

Further, according to the present manufacturing method, clad pipes of various diameters can be easily manufactured and covered by processes such as welding and cutting without using a welding torch for small diameter pipes and without using complicated means.

[Brief explanation of the drawing]

FIG. 1 is a left side view of the tubular core member used in the example. FIG. 2 is a front view of the core member shown in FIG. 1. FIG. 3 is a left side view of the pipe after overlay welding of the clad material on the surface of the core member in the example. FIG. 4 is a front view of the straw shown in FIG. 3. FIG. 5 is a left side view of the tube after forming the built-up outer surface layer in the example. FIG. 6 is a front view of the tube shown in FIG. 5. FIG. 7 is a left side view of a clad pipe manufactured by removing the core member in the example. FIG. 8 is a front view of the clad pipe shown in FIG. 7. 1... Core member 2... Inner overlay layer 3...
Overlay outer layer patent applicant Toyota Motor Corporation

Claims (4)

[Claims] (1) Welding on the inner surface of a tube, comprising a first step of welding a cladding material to the outer surface of a metal core member, and a second step of removing the core member after the first step. Method for manufacturing clad pipes. (2) In the first step, the cladding material is overlay welded to form an overlay inner layer, and then a pipe outer surface layer forming material is overlay welded to the outer surface of the overlay inner layer to form an overlay outer layer. A method for manufacturing a clad pipe with built-up cladding on the inner surface of a pipe according to claim 1. (3) The core member is made of carbon steel, the cladding material is made of Co-based alloy or Cr-Ni alloy, and the tube outer surface layer forming material is made of carbon steel or stainless steel. A method for manufacturing a clad pipe with overlay on the inner surface of the pipe. (4) The welding method for the inner build-up layer is powder plasma welding, and the welding method for the outer build-up layer is MIG (Metal in
3. The method for manufacturing a clad pipe with a built-up inner surface of the pipe according to claim 2, which is a welding method (e.g. ert gas welding).