JPS5832543A - Manufacture and device for clad ingot - Google Patents

Abstract

PURPOSE:To obtain a clad ingot wherein the gradient of the concn. at the boundaries of dissimilar metals is continous and the dissimilar metals are surely joined by casting one kind of metal onto the bottom part of a mold in a nonoxidative atmosphere, allowing the same to solidify upward in one way and casting the next kind of metal thereon before the top surface of the former metal solidifies. CONSTITUTION:While the inside of a mold 10 is held in a nonoxidative atmosphere by blowing gaseous Ar, one molten metal A out of two kinds of metal is charged through a lower inlet 141 for charging of molten metal. The metal A is cast up to a prescribed height and unidirectional solificiation is progressed upward from the bottom part. When the unsolidified part is only the top layer, the other kins of the molten metal B to be clad is cast through an upper inlet 142 for charging onto the molten metal A up to the prescribed height. As a result, the oxidation and interposition of foreign matter at the joining boundaries between the dissimilar metals, that is, A and B are completely prevented, and the surely joined surfaces at both surfaces are obtained. A layer of the components mixed with both metals is created at the above-described two boundaries, and the clad ingot wherein the gradient of the concn. of said components is continuous is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for producing a clad slab in which the bond between different types of older layers is extremely good and there is no concern about delamination due to rolling.

The most common methods for manufacturing clad plates are the casting method and the roll rolling method. In other words, in the former case, one of the two cast slabs (, 2j) to be clad is set in the normal drawing mold (7) shown in Fig. 1 (a), and the other is placed in the state of . Molten metal (3) is injected and the slab (2) is cast into a square ingot (1ll), which is rolled to form a plate (3) as shown in the figure (b), and the two metals are joined together. However, in this method, the hot molten metal comes into direct contact with the slab (2) set in advance, so the surface of the slab (2) is likely to be oxidized and a complete bond cannot be achieved. Even if an antioxidant such as paint is applied to the surface of the H piece (:1) in advance to prevent oxidation, it is difficult to obtain this condition. In the end, it is difficult to expect a very good bond as described above, and although there are no countermeasures, it is difficult to avoid foreign matter from getting caught in either case.

On the other hand, as for the latter roll rolling method, as shown in Fig. 2 (a), the slab (7) (εj) made of each of the plural metals to be clad is overlapped and the surrounding area is completely rolled as shown in (9). Seat welding and soaking as shown in the same figure (b).
There is a method of rolling and crimping the two flanges (71 (#+). In this roll rolling method, when the two flanges are hermetically welded, it is unavoidable that air remains between the two flanges, and this There is a concern that residual air may cause oxidation during soaking or weld peeling due to air expansion, and the residual air itself directly leads to poor crimping between slabs.

Furthermore, in any of the above methods, it is inevitable that the metal component, the so-called concentration gradient, at the bonding interface between different metal layers becomes discontinuous as shown in Figure 2 (b), and the difference in deformation resistance between the metal layers during rolling occurs. As a result, rolling strain tends to concentrate at the interface, and as mentioned above, it is difficult to ensure a perfect interface bonding state, and there is a high risk of flaking occurring there. I felt regretful about being restricted.

In view of the above, the present invention aims to provide a method for manufacturing a clad flange piece that can securely bond the interface between dissimilar metal layers regardless of the type of cladding metal, and also realize a continuous concentration gradient at the interface. This is the first purpose.

The method of the present invention involves first placing one metal among a plurality of metals to be clad in a mold maintained in a non-oxidizing atmosphere and solidifying it in one direction upward from the bottom, so that the upper surface of the metal is in an unsolidified state. The next type of metal is cast on top of the metal while it is still in place, and in this way, the required type of metal is poured so that the concentration gradient at the joint interface between each metal is continuous. In other words, the method of the present invention replaces the joining method of the interface between dissimilar metal layers in the conventional method of slab-molten metal joining (casting method) or slab-molten metal joining (roll rolling method) with semi-molten slab joining. - By switching to molten metal bonding, the bonding state at the interface of dissimilar metal layers is reliable, and the concentration gradient at the interface is continuous, so a clad ingot can be created with no fear of peeling at the interface during rolling. That's what you get.

Furthermore, another object of the present invention is to provide a casting apparatus suitable for carrying out the method as described above. That is, the casting apparatus of the present invention is equipped with a cooling means at the bottom, a closed mold having a heat-insulating lid, and has molten metal injection holes for each of the dissimilar metals to be clad at two or more different required height positions on the side wall of the closed mold, and the inside of the mold. The casting method is characterized in that the cast metal from the injection hole is solidified in one direction from the bottom upward while maintaining the metal in a non-oxidizing atmosphere.

Hereinafter, the present invention will be explained in detail based on the drawings.

Figures 1 and 10 are a perspective view and a longitudinal side view showing an embodiment of the casting apparatus of the present invention, (/4 is a flat mold having a heat-retaining lid Q, and V2 is a flat mold on which the mold is placed. In the base plate, the inner door is provided with a large number of cooling gas passages V3 as means for cooling the molten metal in the armor mold.The side wall (3) of the armor mold (tO,) is provided with a plurality of cooling gas passages V3 at different height positions. Two molten metal injection holes (71
/-, ) (lp2) is provided. The same number of molten metal injection holes are required depending on the number of metals to be cladded, and the opening height position (h/)Q'lJ
) is determined according to the casting height of the molten metal to be injected from there, and in particular, when the molten metal of No. 11 is being poured, it must be made to be above the armored height. For example, the mold (/4) is a pair of long side walls (lOJ) (lOJ) installed in parallel as shown in the plan view of Figure 5.
) It is advantageous to provide the short side wall (toi') (10cm) fitted between the molds so that the position can be changed in the left-right direction or can be attached and removed, in order to make it convenient to remove the 5mm. A blow hole is provided in the mold, and an inert gas, such as an Ar gas supply system, is connected to this hole so that the inside of the mold can be maintained in a non-oxidizing atmosphere.

The procedure for casting a two-layer clad steel ingot according to the method of the present invention using such a casting apparatus is as follows.

First, prior to decay, Ar gas was blown into the mold from the gas blowing hole (/S) provided in the heat-insulating lid V to maintain a non-oxidizing atmosphere inside the mold. (stomach)
As shown in the figure, first open the bath water inlet on the lower side (/II
Inject the molten metal (A) of one of the two metals to be clad through the injection port (
Pour the mixture until it reaches the bottom. At this time, for example, air is passed through the cooling gas passage V3 provided in the base plate V2, and the unidirectional solidification of the cast molten metal (A) from the bottom to the top is promoted by its cooling effect and the effect of the heat-insulating lid V4. .

■ When the molten metal solidifies after being left for a predetermined period of time and only the upper layer remains, another type of molten metal is poured into the cladding hole from the other injection hole (TP) as shown in the same figure (b). Cast to the specified height. FIG. 7 schematically illustrates the state of the full thickness of the casting at this time. The lower layer metal (A) that was cast earlier solidifies sequentially from below, and most of it (A/) is already in a completely in-phase state,
On top of the completely solid layer (A/), there is a solid-liquid coexistence layer (n), and a thin unsolidified layer (A) in a completely liquid phase is left on top of the layer (n), which will be cast later. The metal (B) exists in a molten state adjacent to the unsolidified layer. When cast in such a state and solidified, oxidation and foreign matter at the joint interface between different metals are completely prevented, and a reliable joint is obtained at the interface.Moreover, both metals are mixed at the interface. A layer of these components is formed, and the concentration gradient becomes continuous as illustrated in Fig. g.

■ After complete solidification is completed in this way, see Fig.
C) As shown in the mold (/4 short side wall (lO7) (101
) to the left and right, and remove the insulation lid V4.
Cut out the steel piece (C). This steel piece is then subjected to a rolling process to become a two-layer clad plate with a predetermined thickness.

The above has been described for the case of two-layer clad slabs, but the method of the present invention is not limited to thermal theory, but can also be applied to the production of clad slabs that generally consist of a plurality of different types of bottom layers in the same manner as above. Applicable.

As explained above, the method for manufacturing a clad slab of the present invention involves solidifying the joint between different types of full-flexures by bringing a semi-molten slab made of one metal into contact with the other metal in a non-oxidizing atmosphere. In contrast, it is possible to produce a clad slab in which not only the bonding at the interface between all flexural layers is perfect, but also the concentration gradient at the interface is continuous. This invention can be said to be extremely useful in stabilizing the quality of this type of steel plate by preventing delamination during the manufacturing process of clad steel plates.

[Brief explanation of drawings]

Figure 1 (a), main) is a diagram showing the manufacturing process of clad steel plates by the casting method, Figures 2 (a) and (b) are diagrams showing the manufacturing process of the same steel plate by the roll rolling method, and Figure 3 1 is a perspective view showing an embodiment of a casting device for clad steel ingots according to the present invention, FIG. 1 is a longitudinal sectional side view of the casting device, and FIG. 5 is a preferred example of a mold used in the casting device. Fig. 7 is a process diagram showing the procedure for producing a clad ingot by the method of the present invention, Fig. 7 is a diagram of the progress of solidification of cast metal when the method of the present invention is used, and Fig. 7 is a clad product. This is a graph showing the concentration gradient at the dissimilar metal bonding interface, where (a) represents the case when the method of the present invention is used, and (1:9) represents the case when the conventional method is used. In the figure, l: mold, 2: Slab for cladding, 3: Cast metal, μ: Clad ingot, j: Clad plate 7. f 11 Slab for cladding, Ri: Welded part, lO
: Mold, -If' : Heat insulation lid, 12: Bottom plate, 13: Cooling gas passage, ! ≠: Armored gold rhinoceros inlet, C a) Figure 1 Figure 2 Figure 6 Figure 7 Figure 8 (A)

Claims (1)

[Claims] (1) First, one of the metals to be clad is poured into a mold maintained in a non-oxidizing atmosphere to a predetermined height and solidified in one direction upward from the bottom, so that the upper surface of the metal is still solidified. The next type of metal is cast onto the metal to a predetermined height before the process is completed, and in this way, the required type of metal is cast so that the concentration gradient at the joint interface between each metal is continuous. A method for manufacturing a clad flange piece. (:l) A closed mold with a cooling hand at the bottom and a heat-retaining lid is provided with molten metal injection holes for each of the different types of metals to be clad at two or more different required height positions on the side wall of the mold, and the inside of the mold is completely sealed. A casting apparatus for a clad slab, characterized in that the cast metal from the injection hole is solidified in one direction from the bottom upward while maintaining an oxidizing atmosphere.