JPS6319263B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nozzle for jetting molten metal, and more particularly to a nozzle used to directly manufacture a wide thin plate by jetting molten metal onto the surface of a roll rotating at high speed.

Conventional methods for producing wide thin plates directly from molten metal include the single roll method and the twin roll method. The nozzles used in these methods include a slit type nozzle having a rectangular ejection port and a multi-hole nozzle having a plurality of ejection ports. In the case of a slit type nozzle, since the steady flow length L of the ejected molten metal 2 is short as shown in FIG. Only the roll method is used. In this method, the distance G between the nozzle 3 and the surface of the roll 4 is generally about 1 mm or less, although it depends on the thickness of the plate to be manufactured. Therefore, in the single roll method using a slit type nozzle, problems such as nozzle setting problems, nozzle breakage due to collision between the roll and nozzle due to rise in roll temperature during manufacturing, and occurrence of roll scratches occur. On the other hand, a multi-hole nozzle is a nozzle developed primarily for use with twin rolls. That is, in the case of the twin roll method, since the gap between the adjacent rolls is narrow, the nozzle cannot be brought close to the contact point between the adjacent rolls or the roll surface near the contact point. Therefore, a slit type nozzle that cannot provide a steady flow length of molten metal cannot be used in the twin roll method. Since the porous nozzle 5 has a larger steady flow length L of the molten metal 2 than the slit nozzle, it has the advantage of being able to spray the molten metal away from the contact point A between the adjacent rolls 6 and 7.
In the twin-roll method using a multi-hole nozzle, molten metal is ejected from a plurality of ejection ports, and the molten metal is coalesced at the contact point between adjacent rolls to produce a wide thin plate. However, such a porous nozzle has the following problems. That is, the hole diameter and hole spacing vary depending on the composition of the molten metal and manufacturing conditions, and the directionality and precision of the holes are difficult, making processing difficult. Currently, ultrasonic machining and drilling are used to process the holes in multi-hole nozzles, but due to poor processing accuracy, the directionality and amount of ejected molten metal is uneven, resulting in non-coalescence and failure. It also has the disadvantage that it causes variations in plate thickness, and that it is not possible to manufacture wide thin plates with a uniform shape. Incidentally, in the case of a porous nozzle, the cost increase due to a decrease in yield due to processing accuracy is about three times as much as in the case of a slit nozzle, and the variation in plate thickness reaches about 5 μm. Variation in plate thickness in the twin-roll method using a multi-hole nozzle arises from the uneven temperature rise of the rolls, as the molten metal ejected from multiple spouts is rolled together at the contact point between the rolls. It is based on the difference in thermal expansion of the rolls. For this reason, it is desired to use a slit type nozzle. However, conventional slit-type nozzles cannot be applied to the twin-roll method because a steady flow length of molten metal cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a molten metal ejecting nozzle that can increase the length of a steady flow of molten metal and is easy to process.

The present invention focuses on the fluidity of molten metal in the jetting passage of a nozzle based on the viscosity of the molten metal, and reduces the fluidity of molten metal in the center of the jetting passage of a slit-type nozzle, and at both ends of the jetting passage of the nozzle. The above object is achieved by improving the fluidity of molten metal. Specifically, the tip of the slit-type nozzle has a semicircular shape along the direction of the slit, and the central portion of the nozzle tip protrudes the most.

Hereinafter, an example of the present invention will be explained with reference to the accompanying drawings.

7 to 9, the tip of the heat-resistant container 1 is formed into a semicircular shape, and a nozzle 8 having a slit-shaped spout 8A bored along the semicircumference is formed. Ejection passage 8 provided in nozzle 8
B is a slit-shaped spout 8A with a jet passage length (indicated by _l1 in the figure) in the molten metal spouting direction in the central part.
It is longer than the ejection passage length (indicated by _l2 in the figure) in the molten metal ejection direction at both ends in the length direction.

In the nozzle having such a configuration, the resistance acting on the molten metal flowing from the heat-resistant container 1 into the ejection passage 8B increases at the center of the ejection passage 8B and decreases as it approaches both ends of the ejection passage 8B. Therefore, the fluidity of the molten metal increases as it approaches both ends of the ejection passage 8B from the center. Generally, when a viscous molten metal is ejected in a band-like shape, the ejected band-like stream has a characteristic that it converges in the center part due to surface tension. In this embodiment, the fluidity of the molten metal is better as it approaches both ends from the center of the ejection passage 8B, so even if the ejected band-shaped stream is concentrated at the center due to surface tension, Steady flow L
can be made longer.

In the present invention, in addition to selecting the length of the nozzle ejection passage in the molten metal ejection direction,
By selecting the width of the nozzle jet passage,
The steady flow length of the ejected molten metal can be increased. That is, in the nozzle 9 shown in FIG. 11, the passage width 9c of the jet passage 9B gradually becomes wider from the center toward both ends in the length direction of the slit-shaped jet opening.

In this embodiment as well, the flow resistance of the molten metal decreases from the center to both ends of the ejection passage 9B, so the steady flow length of the ejected molten metal is increased for the same reason as in the previous embodiment. can do. The material of the nozzle is preferably a material that is heat resistant and does not react with molten metal. Generally SiO ₂ ,
Preferred materials include Al ₂ O ₃ , carbon, Si ₃ N ₄ , water-cooled copper, water-cooled aluminum, and materials whose inner walls are coated with ceramic.

As described above, according to the present invention, since the steady flow length of the ejected molten metal can be increased,
It can be installed in either a single roll method or a twin roll method, and wide thin plates of amorphous and crystalline metal can be uniformly obtained.

Example 1 The slit type nozzle shown in Figures 7 to 9 (the width of the slit type nozzle is 0.3 mm, the length is 20 mm, and is made of quartz) was installed above the twin rolls, and the Co We attempted to manufacture a wide thin plate of amorphous metal using ₇₅ Si ₁₀ B ₁₅ (at%) alloy. However, the material of the roll is tool steel, the roll diameter is φ100, the roll rotation speed is 6000 rpm, the pressure between the rolls is 3000 Kg, the molten metal jetting pressure is 0.5 Kg/cm ² , and the jetting temperature is 1250°C.
It is. When a wide thin plate of amorphous metal was manufactured under these conditions, a thin plate with a width of 20 mm, a thickness of 30 μm, and a surface roughness of 0.5 μm was obtained. Maximum plate thickness variation
It was 1 μm. This plate thickness variation value is much smaller than the plate thickness variation value (approximately 5 μm) in the conventional method. Further, when the obtained thin plate was measured with X-rays, it was confirmed that it was a homogeneous amorphous metal.

Example 2 A slit-type nozzle similar to Example 1 except that the material was made of carbon was installed above in a twin roll shape,
We attempted to manufacture a wide thin plate using Al-20%Si (wt%) alloy in an argon atmosphere. Roll material is tool steel, roll diameter φ100, roll rotation speed
When manufactured under conditions of 1000 rpm, 100 Kg inter-roll pressure, 1 Kg/cm ² molten metal jetting pressure, and 800° C. jetting temperature, a thin plate with a width of about 30 mm and a thickness of 200 μm was obtained.
The surface roughness and thickness variation of this thin plate were comparable to those of Example 1, and when the microstructure of the obtained thin plate was observed, there was no crystallization of primary Si, and a fine structure of eutectic Si was observed. Obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an example of manufacturing a wide thin plate by the single roll method using a conventional slit type nozzle, Fig. 2 is a side schematic configuration diagram of Fig. 1, and Fig. 3
Figure 4 shows the length of the molten metal stream and steady flow ejected from a conventional slit nozzle.
The figure is a schematic block diagram showing a method for manufacturing a wide thin plate by the twin-roll method using a multi-hole nozzle, Figure 5 is a side schematic block diagram of Fig. 4, and Figure 6 is a schematic diagram of the method for manufacturing a wide thin plate by the twin-roll method using a multi-hole nozzle. A diagram showing the length of a metal stream and a steady flow, FIG. 7 is a cross-sectional view of a slit-type nozzle showing an embodiment of the present invention, and FIG.
- A cross-sectional view taken along line A, Figure 9 is a bottom view of Figure 7,
Fig. 10 is a diagram showing the stream and steady flow length of molten metal by the slit type nozzle shown in Fig. 7, Fig. 11 is a cross-sectional view of the slit type nozzle showing another embodiment of the present invention, and Fig. 12 is a bottom view of FIG. 11; 1... Heat-resistant container, 2... Molten metal, 3... Slit nozzle, 4, 6, 7... Roll, 5... Porous nozzle, 8, 9... Slit nozzle, 8A...
Spout nozzle, 8B...Gouting passage, 9c...Gouting passage width.

Claims (1)

[Claims] 1. In a molten metal spouting nozzle having a molten metal spout formed in the shape of a slit at the nozzle tip, the nozzle tip has a semicircular shape along the direction of the slit, and the center part of the nozzle tip protrudes the most. A nozzle for spouting molten metal featuring: