JPS5847551A - Production of composite structural pipe - Google Patents

Abstract

PURPOSE:To decrease the porosities of a ceramic layer formed on a composite structural pipe and to improve the strength to the same level as that of a base pipe made of metal in a producing method for said pipe wherein a thermit agent in the base pipe is ignited in a centrifugal force field by adding the SiO2 to the thermit agent. CONSTITUTION:A thermit agent consisting of a mixture of Al and iron oxide is loaded in a base pipe 1 made of metal, and said agent is ignited in the centrifugal force field generated by high speed revolutions, whereby thermit reaction is caused. The molten iron and molten Al2O3 formed by said reaction are separated by gravity, and an intended ceramic layer 4 is coated and formed via a metallic layer 3 on the inside surface of the pipe. Here, powder or particles of SiO2 are further added at 5-15wt% as an additive to the thermit agent. Then SiO2 is melted as well by the heat of reaction and forms alumina-silicate ceramics by melting and mixing with Al2O3, whereby the m.p. and viscosity are decreased, the escaping of bubble from the layer 4 is accelerated and porosities are decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION 4. The present invention is directed to improvements in the manufacturing method of composite structural pipes in which a ceramic layer is coated on the inner surface of a main pipe made of iron or iron alloy by utilizing thermite reaction, and in particular, That cellar ζtsuku layer 0*
? The present invention relates to a method for reducing the L rate.

Composite structure pipes, which are made by coating the inner surface of the pipe with a ceramic layer, are used as industrial piping members for transporting various fluids because the ceramic layer exhibits good TK characteristics such as heat resistance, abrasion resistance, and corrosion resistance. It has a wide range of applications.
- Various methods have been used in the past to produce this type of tube with a suspended structure, but recently, the so-called centrifugal tilmit method, which uses centrifugal force and thermite reaction at 8'M, has recently become the preferred tSU* method. In other words, Al2 is applied to the inner surface of an iron or iron alloy mother pipe such as a steel pipe using the most typical aluminum-iron oxide-based chill reaction. To explain the case of applying ceramic coating on steel, as shown in Figure 1, K, iron-based main pipe (
1) A thermite agent (!l) consisting of a mixture of powders or particles of aluminum (mul) and iron oxide (r・■Os or r-O4) at a certain ratio is loaded into the chamber and rotated at high speed. is ignited in the centrifugal field of
) and the main pipe (1) as shown in Figure 2.
The desired lamic layer (4) is placed on the inner surface of the metal layer (3) through the metal layer (3).
).

1st + 1mt-4AIso@ + 2Fm + 1
99 guns m17 AI, O @ war 3F @ 104 + 8 ml
-+ 4A/srs + 9F* + 194Ko*l
/Al,Os%lk According to this method, it is generally possible to use not only the above-mentioned mul-iron oxide system but also various oxidation systems, and the loading amount can be adjusted. For any metal header tube, a desired thickness can be applied to its inner surface, and the coating has an fII# that is bonded in high adhesion to the header tube through a simultaneously produced metal layer. .

By the way, when applying the muz-r/oxide-based chill 2t reaction to the aforementioned iron-based main tube, which is the most useful and representative type in this centrifugal chill ζ-t method, there are some problems. Further consideration shows that the ramic layer formed in the wK-dominated form in this tube-metal iron-based main tube is composed of α-mu 120s (5 random), as is clear from the reaction formula. However, a problem with the centrifugal thermite agent in this case is that the porosity of the electrostatic layer produced is high.

In other words, from the viewpoint of improving the mechanical properties, especially the strength, of the ceramic layer, it is necessary to reduce the porosity of the two layers in the centrifugal tiling method in general, but in particular, When dealing with double brass tubes that have a high main tube strength, there is a need to increase the strength of the twisted electric ivy layer to the same level K as the main tube strength, so there is a noticeable reduction in the porosity that needs to be improved. 6 The present development fl was made in view of this point, and is based on the iron-based main tube i (A#-F, which utilizes the oxide-based chilzashite reaction) with high 4IK strength. It was created for the purpose of reducing the porosity of the ceramic layer that is produced when applying a seven-layer coating, and its characteristic feature is that a mixture of aluminum and iron oxide is added to the iron or iron alloy main tube. Loaded with Yuruu Thermite agent.

In the method of coating the inner surface of the main tube with a metal and ceramic layer generated by the Chillmit reaction by igniting a chill electric agent in a centrifugal force field and causing a chill reaction, In addition, the thermite agent loaded with silicic acid (stow) powder is added as an additive%/-h
The weight ratio of particles is 6~. It is preferable to add 16 capsules, and it is more preferable to set the loading weight ratio of the thermite agent to the mother tube to 0. ! It is in the range of 5 to 0.66.

The present invention will be explained in detail below. The reason why the high porosity appears in the warping electric layer produced by the Narmitsuna reaction of the M/-F oxide system that is the object of the present invention is as follows.
The melting point of aluminum is as high as about goso'e, and although it is temporarily melted by the intense reaction heat of the chill reaction, it is sufficient to separate the layers of the melt and the molten metal and to allow air bubbles to escape. This is thought to be due to the fact that the melting time was not maintained.

In the present invention, the porosity of the produced ceramic layer is reduced by adding a third substance to the chilling agent and adding an appropriate additive to the chilling agent, and modifying the properties of the warping electric current. This is the basic solution. But 1
The present inventors conducted various experiments on additives to be added to thermite agents.

The target is a reaction system of im/-y oxide Kk%4.

It has been found that the addition of an appropriate amount of silicic acid (810 m2) powder or particles as an additive is significantly effective in lowering the porosity of the atomic layer formed.

In other words, when using a silicic acid additive, the silicic acid is also melted due to the heat of reaction and it is produced. Although it is intimidating.

This melting and mixing of silicic acid promotes the escape of air bubbles from the two layers whose melting point melts, reducing the porosity of the layer, and at the same time, the action of silicic acid causes vitrification. This results in the formation of a dense ceramic layer.

In the present invention, the basic means for solving the problem is to use a chilling agent to which silicic acid is added as an additive, as described above.

In addition to this, it has been found that if the loading weight ratio of thermite agent to the mother tube is properly controlled, it becomes even more effective in reducing the porosity of the ceramic layer10. 100-800
The tube diameter of φ cod is generally manufactured in the range of KTo or 10 to 081 vertical centrifugal force field. t
Ta. The loading weight ratio of thermite agent to the iron-based main tube (thermite agent weight/main tube weight) which is effective for manufacturing and which provides the necessary thickness of the ceramic ivy layer is in the range of o,i to 0.9.

However, according to the research conducted by the present inventors, it has been found that there is a relationship between the loading weight ratio of the thermite agent to the mother tube and the amount of thermite produced after the reaction. Therefore, in the present invention, as will be described in more detail below, in order to reduce the porosity of the Ceracic layer, a suitable amount (6 to 16% by weight) of silicic acid is used as an additive to the thermite agent. At the same time, the centrifugal thermite method is preferably carried out by adjusting the loading weight ratio of the thermite agent to the iron-based main tube to an appropriate range (0.5 to 0.65). It is the ton that will be given.

Tests and test results supporting the porosity reduction effect of the present invention will be listed below, and appropriate manufacturing conditions will be further discussed based on them. Figures 5 and 4 show the porosity and Si
Figure 4 shows the relationship between the amount added and the thermite loading weight ratio.
10. The amount of addition is rough (the porosity is constant according to XXm-R11110BK). As is clear from this result, silicic acid was added as an additive to the thermite agent (with the theoretical blending ratio).

As the amount added increases, the ceramic porosity shows a large influence on the decrease, and at the same time, the decrease in porosity peaks around the chill two agent weight ratio ops and reaches a remarkable minimum value. I can confirm it. The test results shown are r.gos.
- When using A/ series thermite agent,
1@@'o4- In the case of AZ-based thermite agents, it is sufficient to multiply the amount of sio added by a ratio of 0-94, and there is almost no difference. - So, based on this test result, what is the appropriate range for the amount of silicic acid added and the weight ratio of the agent to obtain a composite tube with low porosity? tiK I'll take a look and consider it. In order to determine this appropriate range, it is first necessary to determine to what extent the porosity of the target composite pipe can achieve the desired properties. The 5th wJ shows the relationship between ceramic porosity and ceramic, which is the criterion for this judgment, and was determined by subjecting the target tubes with various porosity to the flat crushing test. It is something that According to Jin's test results, when coating an iron-based main pipe with main pipe strength of 2,500V or more, the ceramic layer must have the same level of strength as the main pipe, and this condition must be met. Therefore, the porosity of K must be suppressed to below a certain level. Therefore, when manufacturing this type of composite tube by the centrifugal chill method, each of the above appropriate ranges may be determined so as to satisfy the condition that the porosity is equal to or less than F.

In order to satisfy the condition that the porosity is less than 1 cm,
From the results shown in Figs. 1 and 4, the amount of silicic acid added to the chilling agent is 6 or more, and in this case, preferably, the loading weight ratio of the chilling agent to the mother tube is in the range of 0.5 to 0.66. , it turns out that there is something. By the way, it can be seen that as the amount of silicic acid added increases, the KIIl porosity tends to decrease, but the amount added is determined from a different perspective, that is, from the viewpoint of stability of the chilled reaction. The upper limit is regulated. Figure 6 shows that samples of chilled double agents to which silicic acid has been added in various ratios are reacted in closed crucibles, and the heat of reaction is kept constant.
This figure shows the relationship between the amount of 810fi added and the calorific value of the thermite reaction, and the results are shown below.

Sin, when it exceeds 1$1, the reaction is H, and even more lb
If it exceeds the rumors, some unresponsive parts will not be suitable for i-use.

Therefore, in order to obtain the desired dense ceramic layer with low porosity, the amount of silicic acid added to the thermite agent should be in the range of 6 to 15 weight, more preferably 1 to 12 weight. It has been found that a more effective means is to adjust the loading weight ratio of the chill double agent to the main tube to a range of o,s to 0.65, more preferably 0.4 to 0.6.

For comparison, we will also explain the case where silicic acid is not added. In this case, the porosity can be reduced to some extent by increasing the amount of chill building agent loaded, but is this possible? However, a sufficient reduction in porosity cannot be expected, and on the other hand, increasing the amount of thermite agent loaded leads to an increase in the thickness of the produced ceramic layer, which poses a serious problem in practical use of the 111 product. When the powder method is applied to a 100φ cod main tube with a cap ratio of about 0.5, the thickness of the rank layer produced is about s, asw.

Next, examples of the present invention will be described.

<Example> F@lOB powder 1 dried at 150°C for 24 hours
909I and mulch powder 6481 were weighed out at the theoretical mixing ratio.

In addition to this chillitizing agent, add silicic acid (810m) powder.
! 55.4f was added to obtain a product containing 10 parts by weight of silicic acid. This was set inside the centrifugation opportunity frame.
14. ! S cod can be evenly distributed on the inner surface of a steel pipe with a wall thickness of 611 m + and a pipe length of 300 m (loaded weight ratio 0.53). Thermite agent to which acid has been added is adhered and filled in the steel pipe by centrifugal force. After that, the number of revolutions of the metal frame was gradually increased, and the thermite agent was ignited. Then, one reaction occurred and immediately ended, and the red-hot state continued for a while.

Next, the centrifugal chill ζ but method was carried out under the same conditions as above using a thermite agent without the addition of silicic acid.

According to the above preparation test results, the thickness of the produced ceramic layer and metal layer was 4M and swi, which was uniform in all cases. However, the porosity of the ceramic porosity is 3 in the former example, while it is 16.5 in the strawberry example.
I had vomit.

Next, the amount of silicic acid added is 6 weight (F@03., 1G10
9 f.

The centrifugal thermite method was applied under the same conditions as above using a thermite agent containing 645 f, 81G theory 12 f), and the results in this case showed that thermite
The porosity was 6. Also, as a result of the crushing and flattening test of this composite pipe ring, the compressive strength of the ceramic two was 660-z. Furthermore, the ceramic hardness is 11 on the micro Vickers scale.
00-1rs00 was obtained.

As described above, the present invention is a technology for the centrifugal chill method in which a ceramic layer is coated on the inner surface of an iron-based main tube by utilizing the Fluoride reaction of Mul-F and oxides. By adding an appropriate amount of silicic acid to the thermite agent, we were able to easily and reliably solve the problem of reducing the porosity of ceramic caps by L1%.
This has significant technical significance as it further enhances the utility value of the ξt method.

[Brief explanation of drawings]

Fig. 1 and 2 WJ are cross-sectional views showing a manufacturing process using the centrifugal TEM method. Figure 1 shows the structure of the ρ-covering layer. Figure 1 and Figure 4 are both covered with iron main pipe! FIG. 3 is a diagram showing the relationship between the OgK porosity of the formed seven-layer laminate, the amount of silicic acid added to the chill blocking agent, and the loading weight ratio of the chill blocking agent to the main tube. Figure 5 is a diagram showing the relationship between the ceramic porosity 4 and the partial compressive strength. This is a diagram showing ゛, , (1) =--iron main tube, (!l-... thermite agent,
[11...Metal! , (41-" Ceramic layer. Patent applicant: Makoto Ishiita - Continued from page 1 0 Inventor: Jiro Tsuchida 1-2-1 Nakamiya Oike, Hirakata City, Kubota Iron Works Co., Ltd. Hirakata Casting Factory ■ Applicant Kubota Iron Works Co., Ltd. No. 2-47 Shikitsu Higashi-chome, Naniwa-ku, Osaka City Procedural amendment (voluntary) 1981 Patent Application No. 144376shij2, Title of invention: Process for manufacturing composite structural pipes 3, Amendments made Related patent applicant (114) Director of the Agency of Industrial Science and Technology Ishizaka Nori (1 other person)
1 Agent Ken Tsuguha 2 7. Contents of the amendment jll l In the 3rd page, line 15 and line $16 of the JI detailed document, "A1, 0.4" was replaced with "Al10s".
1 mole”.・
and correct it.

Claims (1)

[Claims] 1. A tertiary agent made of a mixture of aluminum and iron oxide is loaded into a mother tube made of iron or iron alloy. A method of igniting the thermite agent in a centrifugal force field to cause a thermite reaction, and coating the inner surface of the mother tube with a metal and ceramic layer generated by the chirkit reaction, wherein the material is loaded into the mother tube. 1. A method for manufacturing a monolithic structure pipe, which comprises adding silicic acid (810,) powder or particles in a weight ratio of 6 to 15 times as an additive to the teritizing agent. The manufacturing method according to claim m, wherein the loading weight ratio of the chill building agent to the main tube (chill building agent weight/main tube weight) is in the range of 0.3 to 0.65. The manufacturing method according to claim 1 or 3, wherein the amount of the powder or particles added is 18% by weight. Claim 1 in which the weight/main pipe weight 2) is in the range 11 of 0.4 to 0.6.
i*Production method described in item 1 or 3. −