JPH0129621B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a clad plate, particularly a clad plate suitable as a material for manufacturing electric resistance welded pipes. For example, the use of clad steel pipes that have a cladding layer of wear-resistant material on the inner surface as steel pipes for pipelines that transport abrasive substances such as slurry can be said to be extremely advantageous in terms of durability. . The most common manufacturing method for clad steel pipes is to weld clad plates into ERW pipes, but in order to apply this method, at least the side end faces of the clad plates must be suitable for welding. It is necessary to Normally, both the base metal and the cladding material appear on the side edge surface of a clad plate. Therefore, in order to ensure weldability on the side edge surface, both the base metal and the cladding material must be relatively easily welded. It has to be the material. As is well known, weldability is generally contradictory to wear resistance, etc. Therefore, as shown in the example of the slurry transport pipe mentioned above, the purpose of the cladding may be to provide wear resistance. In such cases, the fact that weldability is required for the clad material means that the wear resistance that can be ensured is limited, and in the end, the original meaning of clad material is diminished. . In other words, when the above-mentioned welding pipe manufacturing method is applied, it is not always possible to fully utilize the inherent characteristic of cladding, which is to ensure contradictory properties at the same time. As a countermeasure for this, the clad steel plate used as the material is made into a clad plate in which the clad material 1 on both end faces is covered with the base metal 5, as shown in the case of a single-sided clad steel plate in Fig. 1, and the base metal is welded. It is conceivable to ensure weldability of the cladding plate side end face by adjusting the strength. In general, there are two methods for manufacturing single-sided clad steel sheets: rolling and explosion bonding, which involve bonding two sheets of different steel types together; and 2 methods, such as rolling and explosion bonding, in which two sheets of different steel types are bonded together. A typical example is the so-called cast-splitting method, in which the two are joined by rolling and then divided.
By any of these methods, it is impossible to obtain a single-sided clad steel plate with a special structure as shown in FIG. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for efficiently and easily manufacturing a single-sided clad steel plate whose both end faces are covered with a base material. That is, the method of the present invention involves fixing two clad layer materials made of clad metal by sandwiching a steel release plate wider than the clad plates, casting this into a base material, and then blooming and rolling. The base material and the cladding layer material are bonded together, and then an edge cut is made at a position in the width direction that only covers the steel peeling plate, and the peeling plate is removed. The feature is that a single-sided clad plate is obtained. Hereinafter, the method of the present invention will be explained in detail with reference to the drawings. FIGS. 2A and 2B are a plan view and a longitudinal sectional side view showing the casting process in the method of the present invention. In the method of the present invention, the following steps are first taken prior to casting. Two cladding layer materials 1 made of the metal to be clad are prepared, and these two cladding layer materials 1, 1 are fixed by sandwiching a steel peeling plate 2 between them. At this time, as the steel release plate 2,
A material wider than the clad layer material 1 must be used, and the surface of the release plate 2 should be
It is necessary to apply a refractory oxide such as SiO ₂ , Al ₂ O ₃ or ZrO ₂ as a release material. The purpose of applying the release material is to facilitate the release of the release plate 2 after rolling, which will be described later. The two cladding materials 2, 2 with the release plate 2 sandwiched therebetween are then set in the mold 3. At this time, the outer surfaces of the cladding layer materials 1, 1 are used to prevent oxidation of the cladding layer materials and to prevent slag generated on the top surface of the molten metal during casting from being caught between the interface between the cladding layer materials and the molten metal. Apply slag repellent material for this purpose. As the slag repellent material, any volatile paint can be used. When setting into the mold 3, the upper edges 1' of the cladding layers 1, 1 are placed at least below the casting height position (A) of the mold 3. The clad layer material may be supported by means such as suspending it within the mold 3 by means of a support frame 4 which is secured to the upper edge 3' of the mold as shown. After preparing as described above, the molten metal 5 selected as the base material is cast. The pouring is performed through the injection port 6 at the bottom of the mold by the bottom pouring method, and the molten metal is poured to a height (A) exceeding the upper edge of the clad layer material 1 set in the mold. The casting step in the method of the present invention is completed above, and the clad ingot obtained in this step is then sent to a bloomer. In the blooming process, reduction is of course performed in the thickness direction, but it is also necessary to perform reduction not only in that direction but also in the width direction. This is to achieve a bond between the side surface 1'' of the clad layer material and the base material 5 as shown in Fig. 3A.The thickness reduction amount is 3 or more and the width reduction amount is 1.1 or more. This is necessary to completely join the base metal 5. After blooming, the lugs are rolled to a predetermined thickness, and then the steel peeling plate 2 is removed to form two single-sided clad steel plates. Cutting is performed. That is, as shown in FIG. 3B, an edge cut is made at a position (B) in the width direction that covers the release plate 2 but does not cover the cladding layer material 1, and the release plate 2 is removed. Since a release material is applied to the surface of the release plate, the release plate 2 can be easily separated from the clad layer material 1 and the base material 5 after cutting. By going through the cutting process, two single-sided clad plates with both side edges 7 covered with the base metal 5 are manufactured at the same time, as shown in Figure C. Such clad plates can be easily welded as the base metal. If a material of high quality, such as low carbon steel, is selected, the weldability of the side edges will be ensured, regardless of the material of the cladding layer. This provides a material suitable for manufacturing clad steel pipes to be welded.Next, examples of the present invention will be described.A clad ingot was cast according to the method of the present invention under the conditions shown in Table 1. .Next, the obtained ingot was
Blooming and rolling were carried out under the conditions shown in Table 2, and then edge cutting was performed to obtain a plate thickness of 24 mm (base material layer:
A clad steel plate as shown in Fig. 1 with a width of 11 mm (11 mm, clad layer: 13 mm) and a width of 2000 mm was obtained.

【table】

[Table] Using this cast plate as a material, 200
Clad steel pipes with an outer diameter of mmφ were manufactured, and during the pipe manufacturing process, no peeling was observed at the boundary between the base metal layer and the clad metal layer, and there were no UST defects. Also, welding is extremely easy to perform under normal conditions, and there is no cracking in the weld.
No defects such as peeling were observed. Furthermore, when the obtained clad steel pipe was subjected to a flattening test, it showed a good flattening height of 0.1 to 0.3D.
The presence or absence of micro-inclusions was also investigated at the boundary between the base material layer and the cladding material layer in the cross-section of the steel pipe, and the presence of inclusions was clearly seen in the cross-sectional micrograph of the boundary shown in Figure 5. was not recognized at all. In addition, the shear strength is 4.1Kg/
A good result of mm ² was shown. As is clear from the above explanation, the method for manufacturing the clad plate of the present invention can be applied to any type of clad metal, as long as the base metal used is easily weldable. It is possible to manufacture a single-sided clad plate suitable as a material,
Moreover, it is highly efficient and easy to implement, and therefore, the present invention makes it possible to fully utilize the characteristics of clad steel in electric resistance welded pipes.

[Brief explanation of drawings]

Fig. 1 is a front view showing a clad plate suitable as a material for manufacturing electric resistance welded pipes; Figs.
Figures 3A, 3B and 3C are diagrams showing the steps of blooming, rolling and cutting of a clad steel ingot based on the method of the present invention;
Fig. 4 is a front view showing an electric resistance welded pipe using a clad plate manufactured by the method of the present invention, and Fig. 5 shows the boundary between the base material and the clad material of the clad plate manufactured by the method of the present invention. 2 is a cross-sectional microphotograph showing the metal structure of . In the figure, 1: Clad layer material, 2: Steel release plate,
3: Mold, 4: Support frame, 5: Molten metal, 6: Molten metal inlet.

Claims (1)

[Claims] 1 Prepare two clad layer materials made of clad metal, and fix the two clad layer materials by sandwiching a steel release plate wider than the clad layer material, the entire surface of which is coated with a refractory oxide as a release material. A volatile slag repellent material is applied to both sides of the mold, the mold is set in a mold, and molten base metal is poured into the mold to a predetermined height above the cladding layer material. The ingot is bloomed and rolled to join the base material and the cladding layer material, and then an edge cut is performed at a position in the width direction that covers the wide steel peeling plate but does not cover the cladding layer material to form the peeling plate. A method for producing a clad board, which comprises removing the clad plate to obtain two single-sided clad plates having both end faces covered with a base metal.