JP2843952B2 - Manufacturing method of thin plate preform - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin sheet preform, and more particularly to a method of manufacturing a thin sheet preform by using a combination of a single roll type caster and a spray deposit device. It is.

[0002]

2. Description of the Related Art Generally, in the production of thin sheet preforms (strips), there is known a production method which simplifies a rolling process, that is, a special continuous casting equipment which performs melting → continuous casting → rolling continuously. This manufacturing method is simple
Roll type, roll belt type, twin roll type, twin belt type, etc.

By the way, a single-roll continuous casting method (single-roll
The strip type caster has a simple structure and a relatively large cooling area. Therefore, for example, it has the advantage of higher productivity than the twin roll type strip caster, but it is difficult to control the wall thickness. Moreover, since the cooling rate on the roll side and the cooling rate on the surface side of the strip are different, there is a problem that defects are likely to occur on the surface layer of the strip, and furthermore, slabs, billets and other cast pieces are produced. However, there is a problem that productivity is much lower than that of a general continuous casting facility.

On the other hand, as a method of manufacturing a thin plate preform,
The spray deposit method is known. In the spray deposit method, a molten metal is atomized by an inert gas, and finely pulverized droplets are rapidly cooled and solidified during scattering and deposited on a collector to form a preform. (Material)
(For example, Japanese Patent Publication No. 54-29985,
JP-B-56-12220 and JP-A-64-15
No. 264, etc.), compared to the ordinary casting method,
It has advantages such as the formation of a uniform microstructure by rapid solidification, the absence of macrosegregation, and the good workability and forgeability. Also, the spray deposit method has a lower porosity and a higher density preform than the thermal spraying method in which a group of molten metal particles are sprayed onto the surface of a coating material to form a laminated coating, and furthermore, productivity is improved. Has high advantages. However, when such rapid solidification is performed extremely, porosity occurs, and a high-density preform cannot be obtained. That is, the cause of this porosity is
If the cooling by the gas becomes too extreme, the ratio of solid phase particles in the particles deposited on the preform becomes high, and the liquid phase and the semi-molten particles that fill the gaps between the solid phase particles decrease, so the solid phase It is considered that the gap between the particles becomes porosity as it is, and when the particle temperature becomes relatively low, the particles are less likely to be flattened at the time of collision, and form a portion that becomes a shadow for particles coming later. However, if the temperature of the particles that come later is sufficiently high in a molten state, the shadow can be filled, but if the temperature is low, it is thought that porosity will not be filled. Therefore, the problem of porosity generation is hidden in the spray deposit method.

The inventors of the present invention have conducted intensive trial and error to solve the above-mentioned problems in the single-roll strip caster. Surprisingly, by combining the spray-deposit method, both problems have been completely solved, and are provided here.

[0006]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a mold roll for a single-roll type strip caster in a chamber in an inert atmosphere for spray deposition. The present invention also provides a method for producing a thin plate preform, which comprises spraying and depositing a thin plate base material cast by the mold roll as a collector.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be described in detail with reference to an embodiment shown in the accompanying drawings. FIG. 1 is a schematic view of an embodiment of the present invention, and FIG. 2 is a micrograph. In FIG. 1, a tundish 3 is provided adjacent to a chamber 1 in an inert atmosphere for performing spray deposition on the upstream side of a pass line of a thin plate preform 2. The tundish 3 is provided with a ladle 4 above the tundish 3.
The molten metal (for example, SUS304) 5 in the inside is successively turned into a molten steel stream 5a and poured. One side wall of the tundish 3 constitutes a moat weir 3a, and a supply section 7 expanded in the width direction corresponding to the width of a mold roll 6 described below is provided below and downstream of the weir 3a. It extends horizontally. In the chamber-1, a mold roll 6 which is in contact with the tip of the horizontal supply unit 7 is rotatably provided horizontally. The mold roll 6, which is not shown, is an ordinary single roll. Similar to the roll used in the roll-type strip caster, it has a diameter of, for example, about 4 m, the outer periphery of which is wound with a thin steel plate, and cooling water is blown from the inside. An atomizer 8 is arranged above the mold roll 6 so that the spray flow 9 can be deposited on the mold roll 6. Therefore, the mold roll 6 has a function of both the mold and the collector of the spray deposit facility. And
A spray deposit ladle 10 is provided on an upper surface of the atomizer 8, and a mold roll 6 is provided.
Is provided with a stripping shoe 11, which facilitates stripping of the thin plate preform 2 at the start of casting and serves as a delivery guide during operation. Further, a rolling roll 12 is provided at the outlet of the chamber 1, and an exhaust gas ventilator 13 is provided at the bottom.

Next, the operation of the apparatus of this embodiment will be described. The molten metal 5 of the tundish 3 gently floats on the supply section 7 over the weir 3a, and slag is not entrained. Flows thinly on the surface of the casting. At this time, even if the molten metal 5 of the tundish 3 comes into contact with the atmosphere and slag is generated, the horizontal supply unit 7 is disposed in the chamber 1 and the chamber 1 is kept in an inert atmosphere. The molten metal 5 cast into the mold roll 6
Has no slag. Then, the thin plate base material 14 is continuously manufactured by the mold roll 6. Next, a spray flow 9 of a molten metal 5b of the same material or a different material from the thin plate base material 14 is applied from the spray depositing ladle 10 using the thin plate base material 14 as a collector.
Is deposited several times thicker than the above, so that the thin plate preform 2 is manufactured continuously. The thin plate preform 2 thus obtained is formed into a thin plate having a uniform thickness by the rolling roll 12.

The thin plate preform 2 according to the present embodiment will be described in comparison with a thin plate preform formed by a normal spray deposit method. That is, the micrograph shown in FIG. 2A shows a thin plate preform (SUS30) according to this embodiment.
4) A cross-sectional micrograph (× 100) of 2 is shown, and (B) similarly shows a spray-deposited one (SUS304) on an ordinary plate-shaped collector. At the interface between a) and the deposit layer (b), the bonding was insufficient, and the porosity (c) was observed in the deposit layer (b). The interface between the layer (a) and the deposit layer (b) of the thin plate base material 14 cast on the steel plate 6 is completely joined, and
No porosity occurred in the deposit layer (b).

When the results are analyzed, in FIG. 3A, the surface layer of the thin plate base material 14 cast on the mold roll 6 is as follows.
Since the cooling is appropriately performed by the spray flow 9, the entire cooling is promoted and no defect due to a temperature difference occurs.
Since the spray flow 9 is deposited on the heated collector (the thin plate base material 14), it is considered that no porosity was generated in the deposit layer (b). In this embodiment, the vertical position of the atomizer 8 is fixed. However, the present invention is not limited to this, and the vertical position of the atomizer 8 is changed to reduce the flight distance of the spray flow 9. Change
The temperature of the particles deposited on the thin plate base material 14 may be adjusted.

[0011]

According to the present invention, in a chamber in an inert atmosphere, a thin plate base material is continuously formed by a mold roll, and the thin plate base material is cast on the thin plate base material. Since the spray deposit is performed, the productivity of the single-roll type strip caster is further improved, and the surface layer of the thin-plate base material is cooled by the spray flow, and the high-temperature thin-plate base material is used for depositing. Porosity is prevented, and a high quality thin plate preform can be manufactured. Moreover, since the mold roll of the single roll type strip caster is used as the collector, the collector
And the trapping amount (several% in Examples) is improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus according to an embodiment of the present invention.

FIG. 2 is a micrograph.

[Explanation of symbols]

1 chamber, 2 sheet preform, 6 mold roll, 9 spray flow

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B22D 23/00

Claims (1)

(57) [Claims] 1. A mold roll of a single-roll strip caster is laid laterally in a chamber of an inert atmosphere in which a spray deposit is performed, and the roll is cast with the mold roll. A method of manufacturing a thin sheet preform, comprising spray depositing a thin sheet base material as a collector.