JPH0455783B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing titanium-based metal clad steel. In particular, the present invention uses low carbon steel and pure nickel or nickel alloy as the insert material.
For example, the present invention relates to a method for manufacturing titanium-based metal clad steel by rolling using an iron-nickel-chromium alloy. (Prior art) Clad materials made by joining dissimilar materials, especially clad steel that uses steel plates as the base material, have been gaining popularity in recent years because they can take advantage of the characteristics of the materials of the composite material and the base material. The demand for clad steel, which uses titanium as a laminated material, is expanding, and the demand for it in seawater desalination plants is increasing.
The development of a reliable and inexpensive manufacturing method is of great significance in terms of its practical application and generalization. Today, clad steel made of titanium material is
Manufactured by explosion bonding method and rolling method using low carbon steel plate (containing pure iron material) as insert material. However, in the explosion bonding method, there is a limit to the size of the assembled slab, and the product size is small. Furthermore, due to poor dimensional accuracy, there are drawbacks such as lack of uniformity in the cladding layer. Furthermore, the bonding strength decreased significantly due to SR (post heat treatment), and the bonding strength was not yet fully satisfactory. On the other hand, in the rolling method using low carbon steel as the insert material, since the diffusion rate of C in Fe is high, C in the base steel plate reaches the Ti interface through the insert material, resulting in the generation of TiC. Even if the thickness of the insert material is increased, C in the base steel material will easily diffuse through the grain boundaries. In particular, when the SR treatment is applied after the thickness of the clad steel is reduced by hot rolling, the diffusion becomes easy. Since the TiC produced in this way is extremely hard and brittle, it is inevitable that the strength of the clad steel obtained in this way will deteriorate. (Problems to be Solved by the Invention) As described above, the precipitation of TiC leads to a decrease in bonding strength, so its formation must be prevented as much as possible. Therefore, as mentioned above, in order to suppress the formation of TiC, low carbon steel or pure iron is inserted at the Ti/base steel interface. However, when manufacturing clad steel sheets by heating and rolling to high temperatures, even if insert materials are used, the carbon contained in the base steel sheet will diffuse through these insert materials to the Ti interface, resulting in a decrease in joint strength. This will cause TiC to precipitate. This tendency is greater as the thickness of the insert material is thinner and the heating temperature is higher. In particular, recently, clad steel has become thinner and processed in large quantities, and rolling at high temperatures has become necessary to increase the amount of reduction in order to increase productivity. In recent years, the generation of TiC as mentioned above has become an important issue. Thus, the object of the present invention is to avoid the problem of TiC formation despite the thinning of the insert material and the high temperature of rolling. An object of the present invention is to provide a method for producing titanium-based metal clad steel. (Means for Solving the Problems) The present inventors have conducted various studies to achieve this objective, and have found that it is effective to use a combination of low carbon steel materials, including pure iron plates, and nickel materials as insert materials. Patent application 1988-38887
A patent application was filed as the No. In other words, brittle intermetallic compounds and TiC are present on the laminate side.
By using a low-carbon steel material that generates less carbon and creates a moderate interdiffusion layer, and using a Ni material as an insert material that slows carbon diffusion between the low-carbon steel material and the base steel material, it is possible to improve the rolling strength. In both cases where post-heat treatment is added, TiC precipitation can be effectively prevented and clad steel sheets with excellent bonding strength can be produced. The inventors of the present invention have further conducted various studies and found that the above-mentioned insert material is not limited to pure Ni, but is effective for nickel alloys in general, and that such pure nickel or nickel alloys and low carbon steel materials The present invention was completed based on the finding that it is also effective to use it as an insert material as an adhesion layer such as a plating layer, a vapor deposited layer, or a thermally sprayed layer. Therefore, the gist of the present invention is to provide a method for producing clad steel by laminating titanium-based metal laminates and base steel plates and hot rolling, in which carbon-containing material is added to the laminate side between the two members. A low carbon steel material with an amount of 0.01% by weight or less is further interposed with pure nickel or a nickel alloy material on the base steel plate side to form a cladding material, and the low carbon steel and/or pure nickel or nickel alloy is used as an adhesive layer. After seal welding is performed on the clad material so that oxygen is not supplied to the joint surfaces between these parts, at least the joint surfaces of the titanium-based metal composite material and the low carbon steel material are vacuum desorbed. This is a method for producing titanium-based metal clad steel, which is characterized by performing air treatment and roll rolling at a rolling start temperature of 500°C or higher and 1050°C or lower. According to one aspect of the present invention, one side of the pure nickel material or nickel alloy material has a carbon content of 0.01.
It may be configured to provide an adhesion layer of low carbon steel of less than % by weight. According to yet another aspect of the present invention, an adhesive layer of pure nickel or nickel alloy may be provided on one side of the low carbon layer material. According to yet another aspect of the present invention, an adhesive layer of pure nickel or a nickel alloy may be provided on one side of the base steel plate. Furthermore, according to another aspect of the present invention, a first adhesion layer of pure nickel or a nickel alloy is provided on one side of the base steel plate, and a low carbon content of 0.01% by weight or less is provided on the first adhesion layer. A structure may also be provided in which an adhesion layer of carbon steel is provided. Note that these adhesion layers are one selected from the group consisting of electrolytic plating layers, electroless plating layers, vapor deposited layers, and thermal sprayed layers. Here, "titanium-based metal" includes pure titanium and titanium-based alloys, and "low carbon steel with a carbon content of 0.01% by weight or less" also includes pure iron. However, so-called stainless steel is not included. Furthermore, "nickel alloy"
Preferably, it is a nickel alloy containing 25% by weight or more of Ni, and more preferably an austenitic alloy containing Fe--Ni--Cr as its main component. In that particular example, the alloy composition, in weight percentages, is limited as follows: Cr≦18, N≧−0.78Cr+26 Cr>18, Ni≧1.13 (Cr−18)+12 Balance Fe and inevitable impurities. Furthermore, in another preferred embodiment of the present invention, the iron-nickel-chromium alloy may further contain 0.05% by weight or less of C and 5% by weight or less of other alloying elements in total. In this way, the present invention recognizes that in order to bond the laminate and the base steel plate with high bonding strength, it is important to cause mutual diffusion of Ti and Fe without precipitating TiC at the interface; This is based on the knowledge that SR treatment of materials further promotes TiC precipitation and reduces joint strength.To solve this problem, it is important not to supply C to the interface with Ti.
For this purpose, low carbon steel is used on the side of the mating material, and pure nickel or nickel alloy with a small diffusion coefficient of C is used as the insert material on the base steel plate side, and at least one of these insert materials is provided in the form of an adhesion layer, Furthermore, if an oxide layer is formed on the surfaces of the laminate, base steel plate, and insert material during heating before rolling,
Since mutual diffusion of Ti and Fe does not occur, vacuum degassing is performed prior to heating to prevent the formation of such an oxide layer. Here, the required thickness of the pure nickel or nickel alloy insert material may be conveniently varied depending on the heating temperature and time and the thickness of the low carbon steel (and pure iron) insert material. There are no particular restrictions. Prior to rolling, the clad material is heated to a predetermined temperature, and as mentioned above, during this heating, when oxygen is supplied to these bonding interfaces, a surface oxidation layer is generated, which is the basis of solid phase bonding. Interdiffusion of elements will not occur. In order to prevent this, in the present invention, it is preferable to perform seal welding on the clad material prior to heating, and perform deaeration treatment to, for example, 10 ^-1 Torr or less. Since the melting temperature of the intermetallic compound that forms at the Ti/Fe interface is 1085°C, the upper limit of the heating temperature at this time is 1050°C.
And so. In order to suppress the diffusion of C from the base steel SS41 steel plate, it is more effective to increase the thickness of the low carbon steel insert material, but if the thickness exceeds 2 mm, the strength of the insert in the shear test will decrease. This is not preferable because it indicates the shear strength of the material itself. (Operation) Next, the present invention will be described in further detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a clad material seen in the manufacturing process of a titanium-based metal clad steel sheet according to the present invention. In Fig. 1, a pure nickel layer or nickel alloy layer 2, which is an intermediate material, is provided on a base steel plate 1, and a low carbon steel (including pure iron) layer 3, which is another intermediate material, is also provided. It is being A titanium plate 4, which is a cladding material, is clad with this low carbon steel layer 3 interposed therebetween. According to the invention,
pure nickel layer or nickel alloy layer 2 and/or
Alternatively, the low carbon steel layer 3 is configured as an adhesive layer. There is no particular limit to the thickness of each plate material, but preferably,
The total thickness of the insert material as the final material is preferably about 0.1 to 10%, usually about 0.5 to 3.0%, of the total thickness of the combined steel plates. Next, a method for producing titanium-based metal clad steel according to the present invention will be explained. (1) Formation of adhesion layer: First, prepare a base steel plate, a titanium material as a mating material, a pure nickel or nickel alloy material as an insert material, and a low carbon steel material. It is preferable that each surface to be joined be made as clean as possible through a process such as degreasing. There are the following four types of insert materials configured as the adhesive layer. An adhesion layer of low carbon steel (contains pure iron, hereinafter the same) with a carbon content of 0.01% by weight or less is provided on one side of pure nickel or nickel alloy material. An adhesive layer of pure nickel or nickel alloy is provided on one side of low carbon steel. An adhesive layer of pure nickel or nickel alloy is provided on one side of the base steel plate. A first adhesion layer of pure nickel or nickel alloy is provided on one side of the base steel plate, and an adhesion layer of low carbon steel having a carbon content of 0.01% by weight or less is provided on the first adhesion layer. In addition, in the following cases, pure nickel material is
The case of electroplating Fe will be explained as an example. (2) Assembly of cladding materials: As shown in Fig. 1, the base steel plate 1, pure nickel material 2 with iron plating layer 3, and titanium plate 4 are laminated, and each insert material and By making the size of the titanium plate slightly smaller than the base steel plate, each material on the base metal is covered with a cover 5 which is another low carbon steel plate, and each seam 6 is welded and sealed. Let it be clad material 7. The insert material has an Fe adhesion layer on the laminate material (titanium or titanium alloy) side, and pure nickel material on the base steel plate side. In FIG. 1, a suction port 8 for degassing is provided in a part of the steel plate 1. (3) Degassing: After obtaining the clad material 7, the inside is degassed using a rotary pump etc. through the suction port 8, and the temperature is reduced to 10 ^-1 Torr.
The degree of vacuum shall be as follows. In the degassing process, high vacuum can be achieved more easily by degassing while heating. When a predetermined amount of degassing is completed, the suction port 8 is shut off by a convenient means such as cutting it by melting. (4) Heating/rolling: The heating temperature is below 1050℃ and above 500℃.
Preferably, a temperature of 700 to 900°C is sufficient. If rolling is finished at too low a temperature, deformation resistance will increase due to work hardening and martensitic transformation.
A finishing temperature of 0.degree. C. or higher is preferred. Thus, in the clad steel produced according to the present invention, virtually no TiC formation was observed, and no decrease in strength was observed even after post-heat treatment. After rolling, the desired titanium-based metal clad steel is obtained by peeling off the steel plate serving as the cover. Next, examples of the present invention will be shown. Example Titanium plate equivalent to JIS H4600 Class 1 (thickness 10mm)
Various tests were conducted using carbon steel (90 mm thick) equivalent to SS41. Low carbon steel or pure nickel material having the chemical composition shown in Table 1 was used as the insert material, and the relationship between the heating temperature and the adhesive layer thickness of these insert materials was determined.
It was investigated in relation to its shear strength according to JIS 601 and JIS 3603.

[Table] These materials were assembled as shown in Figure 1, and evacuated using a rotary pump through a deaeration hole provided at the end.
After reducing the pressure to below 10 ^-1 Torr, the deaeration hole was plugged by welding and heated to 850°C for 5 hours. Then, the shear strength of the rolled material and the plate subjected to post-heat treatment was measured. The investigation was conducted under the conditions that the rolling reduction ratio was 5 and the post heat treatment conditions were constant at 850° C. for 5 hours. The results are summarized in FIGS. 2 to 6. Figure 2 shows that 250 g of FeSO ₄ 7H ₂ O was added to one side of pure nickel material as an insert material.
Bath composition of _PH2.3 containing 120g/( _NH4 ) _2SO4 ,
Fe was electrolytically plated at a bath temperature of 45°C, and the plating layer thickness was varied up to 2000 μm. The graph shows the change in shear strength of a clad steel plate rolled with this Fe adhesion layer on the Ti composite material side and the Ni material on the base material perforated plate (SS41) side. The thickness of the Ni material in this case was kept constant at 300 μm. From the results shown in Figure 2, the thickness of the Fe plating layer is
The bonding strength decreases when the thickness is less than 250 μm, and the reason for this is thought to be that Ni diffuses into Ti through the Fe plating layer and forms a brittle Ti-Ni intermetallic compound layer. In addition, this rolled clad steel sheet was heated at 600°C in the atmosphere.
Even after one hour of heat treatment, the shear strength properties hardly changed. Furthermore, even when Fe was layered by electroless plating, almost the same bonding strength was obtained. Figure 3 shows PH6.0 containing 150 g of nickel sulfate, 15 g of ammonium chloride, and 15 g of boric acid on one side of a low carbon steel material used as an insert material.
Ni was electrolytically plated under a bath composition of 25°C and a bath temperature of 25°C, and the thickness of the resulting Ni adhesion layer was varied up to 1000 μm. This Ni adhesion layer is applied to the base steel plate (SS41).
The figure shows the change in shear strength of a clad steel plate rolled using a combination of low-carbon steel and Ti-laminated steel. In this case, the plate thickness of the low carbon steel material was varied up to a maximum of 500 μm. Here, when the original thickness of the low carbon steel material is 300μm or more, the reason why it shows high joint strength even without the Ni plating layer is because the low carbon steel material itself has carbon from SS41.
This is because it acts as a barrier to prevent Ti from reaching the interface. Furthermore, when the low carbon steel material is relatively thin and the Ni plating adhesion layer is also thin, the bonding strength decreases due to the formation of an embrittled layer of Ti-Ni metal compounds and TiC. The rolled clad steel sheet thus obtained was exposed to air.
Heat treatment was performed at 600°C for 1 hour, and the shear strength measurement results at that time are shown in Figure 4. As can be seen from the results in Figure 4, the thickness of the low carbon steel and Ni plating adhesion layer decreases due to rolling.
Moreover, because the diffusion of C into Fe at this temperature was rapid, the bonding strength decreased in the region where the Ni plating layer was thin. However, as the thickness of the Ni plating layer increases, the strength increases, and similarly to when Ni material is used as an insert material, the Ni plating adhesion layer
It has become clear that it acts as a barrier to the diffusion of C from the atmosphere. Note that even if this Ni adhesion layer is formed by electroless plating, vapor deposition, or thermal spraying, the third
The figure also shows the same results as in Figure 4. In the case of Fig. 5, one side of the base steel plate (SS41) was tested in the same manner as in the test shown in Fig. 3.
Ni was electrolytically plated, and a low carbon steel material was layered on top of this Ni adhesion layer, and then a titanium plate as a laminate material was layered on top of that and then rolled. The results of a shear strength test of the clad steel plate obtained at this time are summarized in FIG. In this case, the thickness of the Ni plating layer was varied up to 100 μm. The thickness of low carbon steel plate is
It was kept constant at 100 μm. The figure shows a rolled clad steel plate heated to 600°C in the atmosphere.
The measurement results of shear strength after heat treatment for ×1 hour are also shown. As is clear from this, the same tendency as in the case of Ni plating on a low carbon steel sheet was observed in this case, and the bonding strength increased as the plating layer thickness increased. Note that almost the same values were obtained even when this Ni adhesion layer was formed by electroless plating, vapor deposition, and thermal spraying. Figure 6 shows that one mating surface of a base steel plate (SS41) is first electrolytically plated with Ni in the same manner as shown in Figures 3 and 5, and then Ni is plated on top of that as shown in Figure 2. This figure shows the progress of a joint strength test of a clad steel plate that was electrolytically plated with Fe using the same method as described above, and a titanium plate as a cladding material was laminated and rolled. In this case, the original thickness of the Ni plating adhesion layer was changed to a maximum of 1000 μm, and the original thickness of the Fe plating adhesion layer was varied in two ways: 100 μm and 500 μm. In this case as well, the results showed almost the same bonding strength as when a plate was used for either Ni or Fe. The shear strength after heating this in the atmosphere at 600°C for 1 hour showed almost the same tendency as shown in Figure 4. Furthermore, this Ni, Fe adhesion layer is electroless plated,
The effects on bonding strength were investigated by changing the layering methods, such as vapor deposition or thermal spraying, and by changing the combinations thereof, but the results in both cases were almost the same as those shown in FIG. 6. (Effects of the Invention) As described in detail above, according to the present invention, when low carbon steel and pure nickel or nickel alloy are used as insert materials, titanium-based materials have excellent bonding strength even when at least one of them is provided as an adhesive layer. Metal clad steel can be easily produced, and titanium-based metal clad steel with high bonding strength after rolling, which hardly changes even after post-heat treatment, can be obtained, making it a reliable and inexpensive rolling method that can replace the conventional explosion bonding method. As a manufacturing method of titanium-based metal clad steel,
The benefits are great.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a partially destroyed cladding material; FIGS. 2 to 6 are graphs collectively showing the bonding strengths of various titanium-based metal cladding steels in Examples of the present invention. 1: Base steel plate, 2: Ni plate, 3: Low carbon steel plate,
4: Titanium plate, 5: Cover, 6: Seam, 7: Clad material, 8: Suction port.

Claims (1)

[Scope of Claims] 1. In a method of manufacturing clad steel by laminating a titanium-based metal laminate and a base steel plate and hot rolling, the carbon content on the laminate side between the two members is 0.01.
% by weight or less of low carbon steel material, further interposing pure nickel or nickel alloy material on the base steel plate side to form a clad material, and configuring the low carbon steel material and/or pure nickel or nickel alloy material as an adhesive layer, After performing seal welding on the clad material so that oxygen is not supplied to the joint surfaces between these parts, at least the joint surfaces of the titanium-based metal composite material and the low carbon steel material are subjected to vacuum degassing treatment. A method for producing titanium-based metal clad steel, which is characterized by rolling the rolled steel at a rolling start temperature of 500°C or higher and 1050°C or lower. 2. The manufacturing method according to claim 1, wherein an adhesive layer of low carbon steel having a carbon content of 0.01% by weight or less is provided on one side of the pure nickel or nickel alloy material. 3. The manufacturing method according to claim 1, wherein an adhesive layer of pure nickel or nickel alloy is provided on one side of the low carbon steel material. 4. The manufacturing method according to claim 1, wherein an adhesive layer of pure nickel or a nickel alloy is provided on one side of the base steel plate. 5 A patent in which a first adhesion layer of pure nickel or nickel alloy is provided on one side of the base steel plate, and a second adhesion layer of low carbon steel with a carbon content of 0.01% by weight or less is provided on the first adhesion layer. The manufacturing method according to claim 1. 6. The manufacturing method according to any one of claims 1 to 5, wherein the adhesion layer is one selected from the group consisting of an electrolytic plating layer, an electroless plating layer, a vapor deposited layer, and a thermally sprayed layer.