JPH0653320B2 - Assembling method of clad steel material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a material assembling method for producing a clad steel containing a Cu-based metal (pure Cu and Cu alloy) as a composite material.

<Prior art and its problems> In recent years, for example, in the fields of seawater desalination equipment and other seawater equipment, chemical industry acid-corrosion-resistant equipment, petroleum refining equipment, etc.
Carbon steel is a base material that is stable in supply and is very advantageous in terms of formability, weldability, cost, etc., and pure Cu or Cu alloy with excellent corrosion resistance (hereinafter collectively referred to as Cu-based metal) The number of cases in which Cu-based metal clad steel with clad steel is applied is increasing remarkably.

By the way, since rolling compression bonding method is advantageous for mass production of clad material from the viewpoint of workability and cost, various rolling compression bonding methods have been devised according to the metal material to be combined. The following method has been adopted when mass-producing such a clad steel material made of a hardly weldable metal material and carbon steel.

That is, as shown in FIG. 2, first, a Cu-based metal-bonding material is superposed on a carbon steel base material, and the Cu-based metal-bonding material having poor weldability is formed from an easily weldable metal (generally carbon steel). After assembling a clad steel material by covering the dummy material and a spacer formed by welding the four sides of their mating surfaces, and then heating and rolling this clad steel material and crimping the carbon steel base material and the Cu-based metal mating material. This is a method of cutting into a desired size and removing the dummy material and the spacer to produce a product. Then, in assembling the clad steel material, it was taken into consideration that both the Cu-based metal-bonding material and the dummy material are used in the same black skin in order to improve the peelability of the dummy material after the rolling and pressure bonding step.

However, with this method, the peelability of the dummy material is relatively good, but the problem is that sufficient bonding of the surface to be originally bonded (clad bonding surface) is likely to be impaired by the black skin oxide layer. was there.

On the other hand, Japanese Patent Application Laid-Open No. 59-30515 discloses, "In order to facilitate separation of the clad materials which do not require joining after the pressure bonding treatment, an inorganic binder such as water glass, soda glass powder or chromite is used as a separating agent. "It is good to use", and Japanese Patent Application Laid-Open No. 62-97781 discloses that "alumina, silica, a black scale of mild steel, between a clad material and a dummy material (encapsulated metal), during annealing. It is easy to remove the dummy material after the pressure-bonding treatment by interposing a release agent such as the annealing separation material. However, when trying to apply these methods, a) preparation of a release agent or a separating agent is necessary at the time of application,
As a result, the effect will vary from person to person. B) It is necessary to apply the formulated release agent or separating agent to a certain thickness and dry it, but there is always an individual difference in the application thickness during application work. The effects vary, and c) it is difficult to judge the applied release agent and the separating agent when the drying is completed, and other problems cannot be ignored, and it cannot be said to be a fully satisfactory method.

In view of the above, an object of the present invention is to provide a clad that can easily and reliably separate "a portion that does not require bonding" after crimping work, and that is stable without being affected by individual differences of workers. It was to establish a method of assembling steel materials.

<Means for Solving the Problems> The present inventor first confirmed the following facts in the course of conducting research while repeating many experiments to achieve the above object.

That is, for example, a titanium foil is inserted between a carbon-containing member such as carbon steel and another metal member (which may be a different metal member or the same kind of metal member), and then heat / pressure bonding treatment is performed on them. When applied, Ti in the titanium foil and C in the carbon-containing member cause a chemical reaction of “Ti + C → TiC”, and titanium carbide (Ti) is formed on the boundary surface between the carbon-containing member and another metal member.
The extremely brittle texture layer of C) is formed. Therefore, even if the carbon-containing member and the other metal member are materials that are easily bonded to each other, the titanium carbide is fragile and fragile in the tissue layer formed at the boundary surface thereof, so that both members can be separated very easily ( Can be peeled off).

Therefore, the present inventor focused on the above fact said that the titanium foil would be an effective release material even in the production of "a Cu-based metal clad steel material in which carbon steel is a base material and Cu-based metal is a combined material". Based on this idea, we conducted an experiment of heating and rolling by inserting a titanium foil between the Cu-based metal and the carbon steel dummy material.In the case of this combination, the Cu-based metal and Ti were It was found that the reaction occurred promptly and the brittle layer made of titanium carbide was insufficiently formed, so that the remarkable effect as expected for the exfoliation of the dummy material was not observed.

Therefore, in order to prevent the direct contact between the Cu-based metal and the titanium foil to prevent the reaction between them, the carbon steel foil and the titanium foil are superposed and the carbon steel foil side is in a positional relationship so as to contact the Cu-based metal-bonding material. An experiment was carried out in which a Cu-based metal and a carbon steel dummy material were inserted between them and heated and rolled. As a result, in this case, the reaction between the Cu-based metal and the titanium foil did not occur, and the brittle layer formed at the “interface between the titanium foil and the carbon steel foil” or at the “interface between the titanium foil and the carbon steel dummy material” It has been revealed that the (TiC layer) makes it extremely easy to peel the Cu-based metal from the carbon steel dummy material thereafter.

However, through a lot of practical work after that, when the above method is used, titanium foil is sometimes left on the Cu-based metal bonding material surface together with the carbon steel foil after the dummy material is peeled off, and this is removed. I knew that a very time-consuming situation would occur. In other words, after separating the dummy material, if only the carbon steel foil is bonded to the Cu-based metal bonding material surface, this can be easily removed by simple maintenance (usually grinding means). If the foil also adheres to the Cu-based metal-bonding material side, it takes a lot of time and effort to remove it because titanium has poor machinability.

The present inventor has continued research by searching for a solution to the above newly found problem. As a result, "The above-mentioned problem is that a carbon steel foil used with a titanium foil as a release material has a carbon content higher than that of a dummy material. It is possible to obtain a new finding that "If it is composed of high steel, it will be solved sufficiently."

The present invention has been made on the basis of the above-mentioned findings and the like. “When assembling a clad steel material in manufacturing a clad steel material using carbon steel as a base material and Cu-based metal as a composite material, FIG. As shown in Fig. 2, the Cu-based metal composite material is covered with a dummy material made of an easily weldable metal (for example, steel), and the Cu-based metal composite material and the dummy material are separated from each other by the "dummy material". In addition, carbon steel foil with high carbon content "titanium foil" is inserted so that the carbon steel foil is on the side of the mating material, and then welding and assembling are performed, thereby significantly improving the assembling efficiency of the clad steel material. The feature is that the dummy material can be separated (peeled) after the clad bonding work easily and stably without being affected by individual differences between workers. ”

<Operation> In other words, the present invention provides “Ti, which is a component of the titanium foil, when the titanium foil is inserted between the“ dummy material which is a separation-requiring member of the clad steel material ”and the laminated material and the heating and pressure bonding is performed. The chemical reaction (Ti +
C → TiC), and a very brittle and fragile texture layer of titanium carbide is generated between the dummy material and the dummy material. ” In the case where is a Cu-based metal, the reduction of the peeling facilitating effect is prevented by the combined use of carbon steel foil, and at the same time, the following points are important requirements. That is, the carbon steel foil to be applied is "carbon steel foil having a carbon content higher than that of the dummy material", so that "the formation of the titanium carbide fragile layer between the carbon steel foil and the titanium foil" is changed to "composite material-titanium". It is prioritized over that between foils so that the separation will occur between the carbon steel foil and the titanium foil during the subsequent peeling of the dummy material, and the titanium foil will adhere to the dummy material and be separated / removed. .

For example, using carbon steel dummy material, weld the four edges of the clad steel material assembled as shown in Fig. 1, heat and roll it, and crimp the base material steel and the Cu-based metal material. Then, during this treatment, the formation of the titanium carbide texture layer proceeds more quickly between the carbon steel foil having a higher carbon content than the dummy material and the titanium foil. Therefore, a sufficient brittle layer is intervened in the interface between the carbon steel foil and the titanium foil in preference to the interface between the dummy material and the titanium foil, and after cutting the obtained clad material to the desired position. If a force to peel off the dummy material is applied, the titanium carbide weak layer formed on the boundary surface between the carbon steel foil and the titanium foil will break more easily, and the dummy material will peel off easily with the titanium foil attached. It will be done.

In addition, FIG. 3 shows "difference in carbon content between the applied carbon steel foil and the dummy material [(C value of the carbon steel foil)-(C of the dummy material.
Value)] ”and“ adhesiveness of titanium foil to dummy material side (ratio of adhered area) ”.
From the figure, it can be seen that when the carbon content of the carbon steel foil is higher than the carbon content of the dummy material, the rate of separation / removal of the titanium foil integrally with the dummy material is significantly increased.

As described above, the carbon steel foil attached to the surface of the Cu-based metal bonding material can be easily removed without any particular trouble by simply taking care of the surface of the Cu-based metal bonding material.

Here, the steel type of the base material steel is not particularly limited, and as for the composite material, pure Cu or various Cu alloys such as cupro-nickel, naval brass, aluminum brass, etc. can be sufficiently effective. It goes without saying that it will be done. Carbon steel (about 0.10 to 0.35 wt% C) is generally applied as the material of the dummy material and the spacer, but the kind is not limited as long as the material is easy to weld. The carbon steel foil to be used is not limited as long as it has a higher carbon content than these, and the higher the carbon content is, the more advantageous it is for peeling (preferably with the carbon content of the dummy material or the spacer. The difference is 0.05% by weight or more, more preferably 0.15% by weight
From the viewpoint of foil production, it is preferable to appropriately select from the carbon content: about 0.25 to 1.00% by weight.

In addition, the thickness of the titanium foil or carbon steel foil to be used is 0.10 to 1.00 mm in consideration of securing peelability and the foil manufacturing cost.
More preferably, it is 0.30 to 1.00 mm.

Next, the effects of the present invention will be described more specifically by way of examples.

<Example> First, the following carbon steel base material, pure Cu laminated material, carbon steel dummy material, carbon steel spacer, titanium foil and carbon steel foil were prepared.

Carbon steel base material C content: 0.03% by weight, dimensions: 100 mm thickness x 2200 mm width x 4000 mm length.

Pure Cu laminated material Dimensions: 30mm thickness x 2160mm width x 3960mm length.

Carbon steel dummy material C content: 0.10% by weight, dimensions: 30mm thickness x 2200mm width x 4000mm length.

Carbon steel spacer C content: 0.10% by weight, dimensions: 30mm thickness x 2200mm width x 4000mm length.

Titanium foil material: JIS Class 1 equivalent, thickness: 0.10 mm and 0.80 mm.

Carbon steel foil used for comparative examples ... C content: 0.10% by weight, thickness: 0.30 mm.

Used in the examples of the present invention ... C content: 0.28% by weight, thickness: 0.30 mm.

Next, after assembling these as shown in FIG. 4, four circumferences of the combined material were hermetically welded to produce a Cu clad steel material.

The clad rolling is carried out at a rolling ratio of 5 after soaking the clad steel material assembled as described above at 980 ° C. for 5 hours,
For the obtained Cu-clad steel materials, "joint state of product", "separability of dummy material", "degree of indentation flaw after separation of dummy material" and "removability of titanium foil from Cu-clad steel material" were investigated. .

These results are also shown in FIG. 4 together with “Comprehensive evaluation”.

As is clear from the results shown in Fig. 4, in the conventional method, the clad product has a poor bonding state (strength) and the dummy material does not have good peeling (separation) properties, and indentation flaws occur on the entire surface of the product. On the other hand, according to the method of the present invention and the comparative method, it is found that the dummy material can be peeled off very easily, indentation defects on the surface do not occur, and a clad product with a good bonding state can be obtained. Further, according to the method of the present invention, the removability of the titanium foil is remarkably excellent as compared with the comparative method, and it can be confirmed that the manufacturability of the clad product is remarkably improved.

<Summary of Effects> As described above, according to the present invention, a high-quality Cu-based metal-clad steel product with a good joining state and no surface indentation is subject to individual differences and skill levels of workers. It is possible to obtain a stable manufacturing process without using any of the above, and it is possible to obtain a very industrially useful effect such that the process after separating the dummy material can be performed very easily.

[Brief description of drawings]

FIG. 1 is a conceptual diagram illustrating an example of an assembling method of a Cu-based metal clad steel material according to the present invention. FIG. 2 is a conceptual diagram illustrating an example of a conventional method of assembling a Cu-based metal clad steel material. FIG. 3 is a graph showing the relationship between the difference in carbon content between the carbon steel foil and the dummy material and the adhesiveness (ratio of the adhered area) of the titanium foil to the dummy material side. FIG. 4 is an explanatory diagram showing an embodiment of the present invention in comparison with a conventional example and a comparative example.

Claims (1)

[Claims] 1. When assembling a crat steel material having carbon steel as a base material and a Cu-based metal as a bonding material, the bonding material is covered with a dummy material made of an easily weldable metal, and the bonding material and the dummy material are also included. Welding and assembling after inserting "carbon steel foil having a higher carbon content than the dummy material" and titanium foil as the release material so that the carbon steel foil is on the mating material side A characteristic method of assembling Cu-based metal clad steel material.