JPH064199B2 - Assembling method of clad steel material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a material assembling method for producing clad steel.

<Prior art and its problems> In recent years, carbon steel (C content: 0.01 to 0.30% by weight), which is stable in supply and is very advantageous in terms of formability, weldability and cost, is used as a base material. High carbon steel (C content: 0.80 ~
1.55% by weight), or the demand for clad steel materials such as high carbon steel-carbon steel, Ti-carbon steel, etc., where clad with dissimilar metals such as Ti or Ti alloys to combine the properties of these dissimilar metals. is doing. For example, members such as kitchen knives and plows for agricultural machinery that require sharpness and wear resistance along with toughness are now usually manufactured using clad steel materials in which carbon steel and high carbon steel are clad. Is.

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, but conventionally, it has been The following method has been adopted when mass-producing a clad steel material made of carbon steel and a difficult-weldable metal material such as carbon steel.

That is, as shown in FIG. 2, first, a high carbon steel laminated material is overlaid on a carbon steel base material, and the difficult-weldable high carbon steel laminated material is covered with a dummy material and a spacer made of an easily weldable metal. Weld the four edges of the mating surfaces to assemble the clad steel material, and then heat the clad steel material.
This is a method in which a carbon steel base material and a high carbon steel composite material are rolled and pressure-bonded, and then cut into desired dimensions, and the dummy material and the spacer portion are removed to produce a product. Then, in assembling the clad steel material, it was taken into consideration that both the high carbon steel laminated 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. However, if the black skin is removed because of this, the problem that the bonding of the clad bonding surface will be good but the dummy material will not come off was difficult. Of course, it is considered that the above problem can be alleviated by removing only the black skin on the surfaces to be joined and leaving the other surface as the black skin, but in order to remove the black skin on only a part of the material, It requires a great deal of work and is not a method that can be adopted industrially at all.

On the other hand, Japanese Patent Application Laid-Open No. 59-30515 discloses, "In order to facilitate separation of clad materials that do not require joining after pressure bonding, an inorganic binder such as water crow, soda glass powder, 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) it is necessary to mix release agents and separating agents at the time of application, which causes individual differences in effect.b) The prepared release agents and separating agents have a certain thickness. It is necessary to apply and dry, but there will be variations in the effect because there will be individual differences in the application thickness during application work.c) It is difficult to judge when the applied release agent or separating agent is completely dried, I could not ignore the problems such as these, and I could not say that it was a fully satisfactory means.

Therefore, an object of the present invention is to easily and surely separate the "portion not requiring joining" after the crimping operation.
Moreover, the purpose was to establish a method for assembling the clad steel material that could be stably performed without being affected by individual differences among workers.

<Means for Solving the Problems> Therefore, the inventors of the present invention have conducted a number of experiments in order to achieve the above-mentioned object, and as a result of repeating the research, “for example, carbon-containing members such as carbon steel and high carbon steel and other When the titanium foil is inserted and adhered between the metal members (which may be different kinds of metal members or the same kind of metal members) and then heated and pressure-bonded, the titanium foil contains Ti and carbon. C in the member causes a chemical reaction of Ti + C → TiC to form a very brittle tissue layer of titanium carbide (TiC) at the interface between the carbon-containing member and another metal member. Even if the metal member and the metal member are easily joined to each other, the brittle and fragile tissue layer of titanium carbide formed at the interface allows the two members to be separated (peeled) extremely easily. ” And the knowledge that Than it was.

Fig. 3 shows that there is a gap between high-carbon steel (C: 0.80 to 1.55%) perforated material and carbon steel (C: 0.01 to 0.30%) dummy material.
"Change in peel strength depending on heating temperature" when 30 mm thick titanium foil is interposed and these are heated to various temperatures and pressure bonded
FIG. 3 is also a graph showing that peeling strength changes extremely when the heating temperature exceeds 800 ° C.
It can be seen that at 850 ° C. or higher, almost no peel strength value is exhibited. This indicates that a chemical reaction of Ti + C → TiC abruptly progresses by heating at 800 ° C. or higher, and an extremely brittle TiC texture layer is formed at the interface.

The present invention has been made based on the above findings and the like. “When assembling a clad steel material in manufacturing clad steel, as shown in FIG. 1, a member that requires separation after clad bonding (first A carbon-containing member (dummy material or laminated material in the example of FIG. 1) at the contact interface of the dummy material in the example of FIG.
By associating with titanium foil and inserting titanium foil, the assembling efficiency of the clad steel difference material is remarkably improved, and "separation of separation member after clad joining work ( It is characterized in that "easiness of peeling" can be secured stably.

That is, according to the present invention, when the titanium foil is interposed between the separation-requiring members of the clad steel material, Ti which is a component of the titanium foil during heating and pressure bonding work and members such as steel (bonding material, dummy) that come into contact therewith. Chemical reaction with C in the material) (Ti + C → TiC)
Is generated and a very brittle and fragile tissue layer of titanium carbide is generated between the separation-requiring members. " For example, using a carbon steel dummy material, the four sides of the mating surface of the clad steel material assembled as shown in FIG. 1 are welded, and this is heated and rolled to crimp the base steel and the mating material. During the treatment, the titanium foil and C in the dummy material react with each other to form a titanium carbide texture layer at the interface between the laminated material and the dummy material. The obtained clad material is cut into desired dimensions. If a force for peeling off the dummy material is applied, the titanium carbide structure layer is a very brittle layer, so that it is easily broken and the dummy material is easily separated.

Here, the steel type of the base material steel is not particularly limited, and the composite material may be any of various steels, Ti and Ti alloys. That is, the present invention is not limited to the case of producing a high carbon-carbon steel clad steel material, but can be applied to an assembly method in which a laminated material and a base material cannot be directly obtained, such as a combination of Ti-carbon steel, and similar effects can be obtained. You can And
Carbon steel is generally applied as the material of the dummy material and the spacer, but the kind is not limited as long as it is a material that can be easily welded.

Further, the thickness of the titanium foil to be used is preferably 0.10 to 1.00 mm, more preferably 0.30 to 1.00 mm, from the viewpoints of ensuring releasability and manufacturing cost of titanium foil.

Figure 4 shows a titanium foil inserted between high carbon steel and carbon steel,
It is a graph showing the relationship between the intervening titanium foil thickness and the high carbon steel-peeling strength of the carbon steel in the joining member obtained by heating and pressurizing this to 1000 ° C. It can be confirmed that a practical peeling effect can be secured if the titanium foil is 0.10 mm or more. Further, since the titanium foil is coiled in each thickness size, there is no change in thickness, so there is no concern that the effect of peelability will change depending on the site or work unit. Moreover, when assembling the clad steel material, it can be freely cut into a desired size and used, so that the work is simple, and there is almost no difference in the effect due to individual differences of operators or skill levels.

FIG. 5 shows an example of assembling the clad steel material according to the present invention, and FIG. 5 (a) is for facilitating the separation of the dummy material and the product part, and FIG. 5 (b). Is one embodiment of the present invention for facilitating the separation of the products when a plurality of clad steel materials are simultaneously produced, but it is not particularly limited to this, and titanium is appropriately placed in an appropriate place according to the work mode and the like. It is sufficient to insert a foil to facilitate the separation of the desired member.

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

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

Carbon steel base material C content: 0.03% by weight, dimensions: 150 mm thickness x 2000 mm width x 4000 mm length.

High carbon steel composite C content: 0.95% by weight Dimensions: 20mm thickness x 1960mm width x 3960mm length.

Carbon steel dummy material C content: 0.13% by weight Dimensions: 30mm thickness x 2000mm width x 4000mm length.

Carbon steel spacer C content: 0.13% by weight Dimensions: 20mm thickness x 2000mm width x 4000mm length.

Titanium foil material: JIS Class 1 equivalent, thickness: 0.30 mm.

Next, after assembling these as shown in FIG. 6, four circumferences of the combined material were hermetically welded to produce a clad steel material.

The clad rolling was performed by heating the clad steel material assembled as described above at 1200 ° C. for 5 hours and then at a rolling ratio of 1: 2. The obtained clad steel materials were “joined state of product” and “separation of dummy material”. The "deterioration" and "the degree of indentation flaw after the dummy material separation" were investigated.

These results are also shown in FIG. 6 together with “Comprehensive evaluation”.

As is clear from the results shown in FIG. 6, in the conventional method, the joining state (strength) of the clad product is poor, and the peeling (separation) of the dummy material is not good, and indentation flaws occur on the entire surface of the product. On the other hand, according to the method of the present invention, it can be confirmed that the dummy material can be peeled off very easily, the indentation on the surface does not occur, and a clad product having a good joined state can be stably obtained.

<Overall Control of Effects> As described above, according to the present invention, a clad steel material capable of obtaining a high-quality clad steel product having a good joining state and no indentation or the like on the surface can be provided to individual workers. Very useful effects in industry can be obtained, such as highly efficient and easy assembly under stable work that is not affected by skill level.

[Brief description of drawings]

FIG. 1 is a conceptual diagram illustrating an example of an assembling method of a clad steel material according to the present invention. FIG. 2 is a conceptual diagram illustrating an example of a conventional method for assembling a clad steel material. Fig. 3 shows the "heating" when a 0.30 mm thick titanium foil is interposed between a high carbon steel perforated material and a carbon steel dummy material and these are heated to various temperatures and crimped. 5 is a graph showing "change in peel strength with temperature". Figure 4 shows a titanium foil inserted between high carbon steel and carbon steel,
It is the graph which showed the relationship between the insertion titanium foil thickness and the peeling strength of high carbon steel-carbon steel in the joining member obtained by heating and pressurizing this to 1000 degreeC. FIG. 5 shows one mode of assembling the clad steel material according to the present invention, and FIGS. 5 (a) and 5 (b) are different modes. FIG. 6 shows an embodiment of the present invention in comparison with a conventional example.

Claims (1)

[Claims] 1. A method for assembling a clad steel material, characterized in that, when assembling a clad steel material, a titanium foil is inserted in contact with a carbon-containing member at an abutting interface of a member that needs to be separated after clad joining.