JPH01228646A - Manufacture of thin metal sheet - Google Patents

Abstract

PURPOSE:To prevent the lug crack of a plate end part and to reduce the yield lowering by the removal of the plate end part by forming a sediment by using the substrate capable of securing the particle flow of a sprayed molten metal in the thickness of an edge part. CONSTITUTION:The sediment of the particle flow of a sprayed molten metal is formed so that its edge part becomes thick and for this purpose a wier 10 is provided in the width direction of a rotary belt 5 to spray the particle for such a substrate. An over-sprayed spraying particle MP is thus collected to an edge part E by the wier 10 and the thickness of the edge part E is secured. The temp. fall of the edge part E is the prevented, the elongation in the width direction is uniformized as well and the metal sheet having no lug crack can be obtd. without applying a tensile stress on the edge.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing sheet metal directly from molten metal.

[Conventional technology]

The most common method for producing thin sheets directly from molten metal is the strip caster method, in which molten metal is injected between a pair of rotating rolls. The reality is that it has not yet been put into practical use due to problems such as spillage and difficulty in controlling the solidification of molten steel on rotating rolls.

As an effective method to solve this problem, a droplet casting method (hereinafter referred to as the spray method) as seen in, for example, Japanese Patent Publication No. 46-43688 has been proposed, and the present inventors also No. 62-67234, a practical method for manufacturing thin metal sheets by spraying was proposed.

[Problem to be solved by the invention]

However, it has been found that these methods are insufficient in the following points. In other words, because the wall thickness of the plate edge of the sprayed deposit becomes extremely small, so-called edge cracking is likely to occur during in-line hot rolling immediately after spraying, especially when manufacturing difficult-to-work metal thin plates. The point is that it becomes.

As a result, the end portion of the plate must be cut and removed after rolling, which unavoidably reduces yield. In addition, the plate may break during rolling, or pieces of cracked edges may get caught in the horizontal rolls, resulting in the product being finished. This has the problem of causing surface flaws on the rolls or damaging the rolls.

In general, various countermeasures have been proposed to prevent edge cracking during hot rolling of difficult-to-process materials. For example, there is a method of welding a material with good workability to the edge of the plate, and a method of suppressing the generation of tensile stress due to temperature drop at the edge of the plate.
There are known methods such as heating the edge of the board using gas burners, induction heating, plasma heating, etc., and crimping the edge cracks using a caliber roll edger, but none of these methods are suitable for use in spray equipment. is inappropriate or
There are problems such as not being expected to be effective.

[Means to solve the problem]

The present invention was made as a result of the above-mentioned study on the relationship between the deposition state of spray particles and the occurrence of edge cracking. This is what I did.

The present invention will be explained in detail below.

FIG. 1 shows an example of a method for manufacturing a thin metal plate, which is the object of the present invention, in which 1 is a tundish containing molten metal, 2 is a tundish nozzle, and 3 is an atomizer 14.
is Surin 1-nozzle.

5 is a rotating belt (endless belt) that is a substrate, 6
is a rolling mill, and 7 is a coiler.

The molten metal in the tundish nozzle 1 becomes a molten metal flow (M) through the tundish nozzle 2, and flows into the rotating bell 1 5.
fall towards. The atomizer 3 is located opposite to both sides of the molten metal flow (M), and injects a high-speed gas jet flow 8 obliquely downward, which collides with the molten metal flow (M). This atomizes the molten metal into particles. Each holotropic particle rapidly solidifies due to convective heat transfer with the high-velocity gas. Furthermore, in order to deposit such a metal particle stream (Mp) with a uniform thickness in the width direction of the rotating belt 5, the metal particle stream (Mp) is deposited from a pair of slit nozzles 4 provided below the atomizer 3. Gas 9 is sprayed. This slit nozzle 4 blows gas 9 onto the metal particle flow (Mp) from both sides, thereby narrowing down the falling range of the particle flow to a predetermined range.

The particles are deposited on the rotating belt 5 in a semi-molten state or in a high temperature state immediately after solidification to form a deposit.

Deposit (II)) is close to true density, but
In order to achieve true density and improve surface properties, it is rolled by a rolling mill 6 and wound up by a coiler 7.

The process from molten metal spraying to rolling is as follows:
It is desirable to carry out the process in a non-oxidizing atmosphere to prevent oxidation. Moreover, a rotating drum can be used as the substrate instead of the rotating belt.

Figure 2 (a) shows a cross section of the deposit in the width direction of the rotating belt when conventional methods are used to manufacture such thin plates, and Figure 2 (b) shows its thickness distribution. be. As shown in FIG. 2(a), in order to make the width of the deposits uniform, particles (MP) are oversprayed and deposited in the width direction of the rotating belt. However, at this time, the edge portion becomes thinner as shown in Figure 2 (b), and this, combined with the temperature drop at the edge portion, results in a difference in elongation between the edge portion and the center of the sheet width. This generates tensile stress in the parts, causing cracking of the edges.

For this reason, in the present invention, the deposit is formed so that its edges are thick, and a special substrate is used for this purpose.

FIG. 3 shows the implementation status of the present invention, in which the rotating belt 5
A weir 10 is provided in the width direction of the substrate, and particles are sprayed onto such a substrate.

As a result, oversprayed spray particles are collected at the edge portion by the weir 10, and the thickness of the edge portion is ensured. FIG. 4 shows the thickness distribution in the width direction of the deposit thus formed, and it can be seen that the thickness of the edge portion (fE) is sufficiently ensured and maintained by the weir 10. By ensuring the edge thickness in this way, a drop in temperature at the edge is prevented, and the elongation in the width direction is made uniform, so the metal plate is free from edge cracks and no tensile stress is applied to the edges. can be manufactured.

FIG. 5 shows an example of the deposition state of the edge portion (E) according to the method of the present invention. Furthermore, Fig. 6 shows the relationship between the height of the weir and the edge portion, and even if the height of the weir is less than the height of the sediment, the edge portion is sufficiently secured.

Note that the weir preferably has a tip as sharp as possible and a smooth surface in order to prevent spray particles from adhering to the weir.

Furthermore, when heating the substrate (rotating belt or rotating drum) to ensure the temperature of the material entering the rolling mill, it is preferable to also heat the weir 10 portion.

FIGS. 7 and 8 show an example of the state of implementation of the present invention, in which the weir 10 uses equipment integrated with the substrate.

In FIGS. 9 and 10, the weir 10' is provided independently of the substrate and can rotate in synchronization with the substrate, and an endless chino or belt-shaped weir is installed on both sides of the rotating belt 5. Bell rotating the paired weir 10']
・It is arranged so that it touches both sides. This weir 1
0' is held by a wheel 11 and rotated in synchronization with a rotating belt. According to such equipment, as shown in the same figure, by applying the weir 10' only to the part where the particles are deposited in the longitudinal direction of the substrate, it is possible to prevent the temperature drop at the edge of the deposit due to heat transfer to the weir. be able to.

Note that the weirs 10, 10' as described above can be similarly provided when the substrate is a rotating drum.

〔Example〕

A sendust alloy plate was manufactured under the following conditions using the apparatus shown in FIGS. 7 and 8.

◎Metal material quality: 9.6%Si, 5.4%AQ, remaining Fe melting temperature: 1.450°C ◎Tandite nozzle diameter near, 0ψ0n◎Atomizing gas component: N2 Pressure: 7. Okgf/d flow rate
: 2. ONrn'/min◎Slit nozzle gas component: N2 Pressure: 2.0 kgf/cJ Flow rate: 0.5NM/mj, n◎Rotating belt (substrate) Material: Ca5t
Iron surface roughness: RzlOμm Speed: 1.5 mm/see Surface temperature: Room temperature ◎ Weir type: Independent type (rotating synchronously with rotating belt) Material: Ca3t Iron surface roughness
:Rzl μm Height = 2ffl'n ◎Deposit (thickness x width): 5 mm x 1.30 w+
◎Rolling mill reduction rate: 30% (rolling mill plate thickness 3.5nrn
) The metal plate obtained in this example had a very sound edge after rolling, and a large width expansion of about 135 mm.
I got an A degree.

〔Effect of the invention〕

According to the present invention as described above, in the production of thin plates by the so-called spray method, it is possible to prevent the occurrence of edge cracks at the edge of the plate, thereby reducing the decrease in yield due to cutting and removal of the edge of the plate, and It also appropriately prevents plate breakage during rolling, making stable rolling possible.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of manufacturing a thin metal plate by a spray method. FIG. 2(a) is an explanatory diagram showing the cross-sectional shape of a deposit obtained by the conventional method, and FIG. 2(b) shows its thickness distribution. FIG. 3 is an explanatory diagram showing the cross-sectional shape of the deposit obtained by the method of the present invention, and FIG. 4 shows the plate thickness distribution of the deposit obtained in FIG. FIG. 5 shows an example of the deposition state of the edge portion of the deposit obtained by the method of the present invention. Figure 6 shows the relationship between weir height and sediment edge category. 7 and 8 show one implementation state of the present invention, with FIG. 7 being an overall explanatory view, and FIG. 8 being a sectional view taken along the line X--X in FIG. 9. 9 and 10 show other implementation situations of the present invention, with FIG. 9 being an overall explanatory diagram and FIG.
The figure is a sectional view taken along the line XX in FIG. 9. In the figure, 1 is a tundish nozzle, 2 is a tundish nozzle, 3 is an atomizer, 14 is a slit nozzle, 5 is a rotating belt, 6 is a rolling mill, 7 is a coiler, 8 is a high-speed gas jet stream, 9 is a gas, 10, 1.0' is a weir, (M) is a molten metal flow, (Mp) is a metal particle flow, (D) is a deposit,
(E) is the edge part. Figure 1 Figure 3 Figure 4
Figure 5, Figure 6, C? , plate thickness in the central part of the prefecture] ('10) No. 7
Figure 8/ Figure 9 Figure 10

Claims (1)

[Claims] The molten metal flows out of a nozzle, the molten metal stream is blown with a gas jet stream to form a stream of particles, the particles are deposited on a substrate, and the deposits are continuously peeled off from the substrate in strips. A method for producing a thin metal plate by rolling the thin metal plate with a rolling mill, the method comprising forming a deposit using a substrate that can ensure the thickness of the edge of the deposit.