JP2003191054A - METHOD FOR PRODUCING Zn-Al BASE ALLOY WIRE ROD FOR THERMAL-SPRAYED COATING - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a wire rod for thermal-sprayed coating at a low cost by continuously casting molten Zn-Al base alloy into a bar-state and successively, rolling. <P>SOLUTION: The molten alloy composed of 0.6-22.0 mass% Al and the balance substantially Zn is continuously cast with a belt and wheel caster provided with an endless belt running while bringing into contact with a rotated casting wheel having a circumferential groove in this peripheral surface under state of covering the circumferential groove so that temperature of the cast material when this material separates from the casting wheel becomes ≤275°C. In succession to the casting, the temperature of the material to be rolled at the inlet of a rolling mill is made to ≤275°C and this material is rolled at ≤275°C while using lubricator emulsion. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a Zn-Al alloy wire rod for thermal spray coating, which is coated on the surface of steel products or the like to prevent corrosion.

[0002]

2. Description of the Related Art Steel as it is causes corrosion even in a relatively mild environment, shortens the usable period, and is not preferable in terms of safety when strength is required. Therefore, in a steel product or the like used in an environment where corrosion is likely to occur, its surface is coated with a Zn-Al based alloy in order to suppress corrosion. Examples of the coating method include a method of immersing a steel product in a molten Zn-Al alloy, a method of spraying a Zn-Al alloy on the steel product, and the like. In steel products manufactured by forming and processing a steel plate plated with Zn-Al alloy in advance, the plating layer is often peeled off during forming, welding, or installation as a product. An Al-based alloy may be sprayed.

[0003]

The Zn--Al alloy wire used for such thermal spray coating is manufactured by hot extrusion or rolling of a casting cast in a mold. For example, in Japanese Unexamined Patent Publication (Kokai) No. 1-108356, a steel bar having a diameter of 30 mm is obtained by melting in a vacuum, casting with a die, heating at 300 ° C. and forging, and further heating the steel bar at 200 ° C. It is described that wire drawing is performed to obtain a wire rod having a diameter of 3 mm. Zn-Al alloys have poor castability, are prone to casting defects such as cavities, have a low melting point, and are easily softened during processing. Therefore, complicated steps are required for hot extrusion and rolling. It becomes necessary and the production cost of the wire for thermal spray coating is high. The present invention has been devised to solve such problems, and Zn-A
An object of the present invention is to provide a method for producing a wire for thermal spray coating at a low cost by continuously casting a 1-type alloy molten metal into a rod-shaped body and rolling it after casting.

[0004]

SUMMARY OF THE INVENTION Zn for thermal spray coating of the present invention
In order to achieve the object, the method for producing an Al-based alloy wire rod has an alloy melt containing 0.6 to 22.0 mass% Al and the balance being substantially Zn, and having a circumferential groove on the circumferential surface. When the casting is separated from the casting wheel continuously by a belt-and-wheel casting machine equipped with a rotary casting wheel and an endless belt that runs in contact with the rotation casting wheel so as to cover the circumferential groove. Casting is performed so that the temperature of the casting object is 275 ° C or lower, and following casting, the temperature of the material to be rolled at the rolling mill entrance is 275 ° C or lower, and rolling is performed at a temperature of 275 ° C or lower while using a lubricant emulsion. It is characterized by doing.
The Zn-Al-based alloy may further contain one or more of 0.1 to 3.0 mass% of Si and 0.01 to 1.0 mass% of Mg. The lubricant emulsion used during rolling has an oil content of 5 to 15 volume% by mixing rolling oil and water.
The cross-section reduction rate during rolling is preferably in the range of 60 to 98%. Then, after rolling, subsequently performing annealing and cold drawing,
It is also possible to use finer wire. If the annealing before the cold drawing is performed at 200 to 300 ° C., the cold drawing becomes easy.

[0005]

In recent years, in the production of metal strips, wire rods, etc., in order to reduce the cost by simplifying the production process, continuous casting of molten metal without continuous cooling without further cooling, Delineation is being carried out. However, in Zn-Al alloy, the characteristics, especially the mechanical characteristics at high temperature, are significantly different from those of pure Zn or Al, so that it is extremely difficult to handle, and casting and rolling cannot be connected. It was For example, 85% Zn
The temperature change of the yield stress when the -Al alloy was subjected to a tensile test at different temperatures is shown in FIG. 1 in comparison with that of pure Zn and Al. As can be seen from this figure, the yield strength of Zn-Al alloy changes greatly depending on the temperature. Therefore, Zn-
When the cast body of Al alloy is handled, it is easily cracked unless the temperature is controlled, and handling is extremely difficult.

The present inventors examined the cause from the phase diagram of Zn-Al alloy. FIG. 2 shows a phase diagram of the Zn-Al alloy. A Zn-Al alloy has a transformation point at 275 ° C.
Therefore, the γ phase appears in the region exceeding 275 ° C., and the mechanical properties deteriorate. The Zn-Al alloy cast body is 2 after casting.
Since it is often handled in a temperature range exceeding 75 ° C. and it is easily cracked, it is presumed that it could not be conveyed continuously in the rolling process. Therefore, the present inventors believe that if a Zn-Al alloy cast body can be handled without cracking in a γ-phase-free region, the temperature of the cast body when the cast body is separated from the casting machine is set to a transformation point of 275 ° C or lower. Stipulated in. By controlling the temperature of the cast body to 275 ° C or less, Z
The rod-shaped cast body of the n-Al alloy could be continuously conveyed to the rolling mill.

Further, when ordinary rolling is performed, the temperature of the material to be rolled may become high due to the working heat generated during rolling. In the case of Zn-Al alloy, if the transformation point is exceeded, the characteristics of the material itself become large. It changes (softens) and becomes difficult to roll. Therefore, it was possible to perform smooth rolling by rolling at a temperature of 275 ° C. or lower while using a lubricant emulsion that also serves as a coolant.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION First, Zn for thermal spray coating produced by the present invention.
The alloy composition of the Al-based alloy wire will be described. Al: 0.6 to 22.0 mass% Al added to Zn forms an α-Al layer and has an effect of delaying the progress of corrosion, but if it is less than 0.6%, it is almost an α-Al layer. Are not formed, and this effect cannot be obtained. On the contrary, if it is added in excess of 22.0%, the hardness of the alloy wire becomes high and it cannot be manufactured by continuous casting and rolling.

Si: 0.1 to 3.0% by mass Si exhibits an action of improving castability, but 0.1% by mass
If the content is less than this, this effect is small, and conversely, if added in excess of 3.0%, the elongation of the alloy wire is reduced, and it tends to crack during rolling, drawing, or winding of the wire. Mg: 0.01 to 1.0 mass% Mg has the effect of increasing the strength of the alloy wire and preventing cracks during rolling, drawing, or winding of the wire. This effect is small if it is less than 0.01%, and conversely if it is added more than 1.0%, the strength becomes too high and it becomes difficult to feed the wire during rolling.

Next, the continuous casting method will be described. In the method for producing a Zn-Al alloy wire rod for thermal spray coating of the present invention, the rotary casting wheel having a circumferential groove on the circumferential surface and the previous term rotary casting wheel are run so as to cover the circumferential groove. Use a belt and wheel caster with an endless belt.
The outline is shown in FIG. Circumferential groove 2 on the circumference of rotary casting wheel 1
The endless belt 3 is run in contact with the circumferential surface of the rotary casting wheel 1 so as to cover the circumferential groove 2 over an angular range of about 200 degrees (depending on the device). . The inside of the circumferential groove 2 thus covered with the lid becomes a casting cavity. A Zn-Al based alloy melt having a desired composition is continuously supplied into the casting cavity by the spout 4. The supplied molten metal is cooled and solidified by the rotary casting wheel 1 and the endless belt 3. It is preferable that a cooling means such as spraying of cooling water is installed inside the rotary casting wheel 1.

When the endless belt 3 comes off the circumferential groove 2 as the rotary casting wheel 1 rotates, the cast body 6 also comes off the circumferential groove 2. Then, when the tip end portion of the cast body 6 is slightly bent (about 10 to 20 degrees) at a time point when the cast body 6 is completely separated from the circumferential groove 2, as the casting progresses, the cast body 6 continues without contacting the endless belt 3 again. It is taken out from the casting machine. Since the cast body 6 manufactured in this manner has less inclusion of oxides and the like during casting and does not have a free solidification surface that is solidified by contact with air, a product with very few oxides can be obtained as a whole. Subsequent processing is easy and a product extremely advantageous as a material for thermal spray coating is obtained.

The cast body 6 taken out from the continuous casting machine is
Guided to rolling equipment. In addition, since the cast body taken out from the rotary casting wheel is curved and bent when it is separated from the casting wheel or during transportation, it is necessary to straighten the cast body through a roll straightening machine before introducing it to the rolling mill. Is preferred. For rolling, the temperature of the rolled material at the entrance of the rolling mill is 275
Adjust the temperature below ℃ and use a lubricant emulsion while using 27
It is performed at a temperature of 5 ° C or lower. The Zn-Al alloy cast body is 27
When it exceeds 5 ° C, it is rapidly softened and too soft to be rolled. Also, if the temperature of the cast body is too low, it becomes hard,
It is preferable to roll at 150 ° C. or higher because the rolling roll becomes difficult to be bitten and the cast body may not be fed.

The temperature at the inlet of the rolling mill can be adjusted by installing a heating device in front of the rolling mill. However, the temperature at the outlet of the continuous casting machine is adjusted by adjusting the cooling means 5 of the continuous casting machine. Controlling is preferable in terms of cost. When rolling,
Use a lubricant emulsion that also serves as cooling. This emulsion is a mixture of rolling oil and water, and it is preferable to use one in which the oil concentration of the rolling oil is adjusted to 5 to 15% by volume. If it is less than 5%, the oil content is small, and the cooling may be too effective during rolling to harden the cast body, which may prevent the cast body from being sent in advance. On the other hand, if more than 15% is used, cooling may be insufficient and the temperature of the casting may rise, resulting in abnormal softening, roughening the surface of the rolled wire rod, or failure to perform rolling itself.

If the cross-section reduction rate during rolling is small, the voids in the ingot cannot be sufficiently crushed, and cracks are likely to occur during winding of the wire rod and cold drawing. Also, if the cross-section reduction rate is large, the temperature drop of the ingot during rolling becomes severe,
It becomes difficult to roll. Therefore, rolling reduces the cross-section reduction rate of 60.
It is preferably carried out in the range of ˜98%. As described above, it is possible to further thin the wire by performing annealing and cold drawing after the rolling. Annealing and cold drawing are carried out under the conventional conditions.

[0015]

EXAMPLES Experimental Example 1 Alloy No. 1 in Table 1. The molten aluminum alloy having the composition shown in 1 is kept at 570 ° C., and the outer diameter is 140 mm.
Then, a belt and wheel casting machine having a rotary casting wheel having a circumferential groove having a depth of 30 mm and a maximum width of 30 mm was cast to have a cross-sectional area of 550 mm ² . A at the exit of the casting machine
The temperature of the 1-Zn alloy cast body was set to 300 ° C, 250 ° C, 23 ° C.
Casting was performed by changing the cooling conditions of the casting wheel so that the temperature was 0 ° C.
When the temperature was adjusted to 250 ° C or 230 ° C, the cast body was removed from the casting wheel and guided to the guide roll while curving, and the cast body could be continuously taken out. However, when it was set to 300 ° C, it was separated from the casting wheel and guided to the guide roll. When I tried to bend it, it cracked and I couldn't guide it to the guide roll.

[0016]

Experimental Example 2 As in Experimental Example 1, the molten aluminum alloy having the composition shown in Table 1 was held at 570 ° C. and cast by the belt-and-wheel casting machine having the rotary casting wheel used in Experimental Example 1. did. The temperature of the Al—Zn alloy cast body at the outlet of the casting machine was adjusted to 230 ° C. and continuously cast, and the cast body was guided to a rolling mill after passing through a roll straightening machine and a heating device. Under the conditions shown in (1), the product was rolled and wound at a cross-sectional area reduction rate of 92% so that the cross-sectional area was 45 mm ² .

[0018] As the rolling mill, using 3-way rolling mill, the cross-sectional area 45 mm ² using a rolling roll 15 stages
Rolled up. At the time of rolling, 120 ml / min of an emulsion in which rolling oil made of mineral oil and water were mixed at a ratio shown in Table 2 was supplied between the rolling mill and the cast body. A gas burner type heating device was provided in front of the rolling mill to adjust the temperature of the casting at the entrance of the rolling mill, and the temperature of the casting at the entrance of the rolling mill was adjusted to the value shown in Table 2. The rolling condition is also shown in Table 2.

Experimental Example 3 An aluminum alloy having the composition shown in Alloy 1 in Table 1 was cast under the same conditions as in Experimental Example 1, the inlet temperature of the rolling mill was 230 ° C., the rolling oil concentration of the lubricant emulsion was 10%.
Under the condition of (flow rate 110 l / min), the cross-section reduction rate is 50
%, 65%, and 95%, and the number of rolling rolls used in the three-way rolling mill was changed to perform rolling. After rolling, it was once wound into a roll. Then, the surface condition of the wire was observed. The results are also shown in Table 2.

[0020]

In Table 2, ⊚ indicates that rolling was possible without any problems, and ∘ indicates abnormal softening of the material to be rolled and protrusion between rolling dies, resulting in defective products at a rate of 5% or less. On the other hand, Δ indicates that rolling was possible, but the material to be rolled became hard during rolling and the desired area reduction rate could not be reached, and x indicates that it could not be rolled because it collapsed in the first rolling. In addition, note ¹⁾ indicates that although rolling could be done without problems, disconnection often occurred during roll winding.

As can be seen from the above results, the test No. No. 1 which was cast and rolled satisfying the conditions defined in the claims. 1 to 6 and No. In Nos. 8 to 10, rolling could be performed continuously from casting, and a wire for thermal spraying was obtained. In No. 7, abnormal softening and crushing occurred in the first rolling, and rolling itself could not be performed. However, test N in which the oil content of the rolling oil in the lubricant emulsion used was low
o. In No. 5, the desired cross-section reduction could not be achieved, probably because the material to be rolled became hard due to excessive cooling. In addition, test No. 1 in which the rolling oil contained a large amount of oil in the lubricant emulsion.
In No. 6, there was a portion where the surface condition of the product was deteriorated due to softening due to the occurrence of a part where the temperature was high in the material to be rolled and protrusion between rolling rolls. Furthermore, the test No. in which the target cross-sectional reduction was 50%. In No. 8, the rolling itself could be performed without problems following the casting, but it was not possible to sufficiently crush the casting defects such as the cavities formed in the cast body by the rolling. Was occurring.

[0023]

As described above, according to the present invention, when the rotary casting wheel having the circumferential groove on the peripheral surface is used to separate from the casting wheel of the continuously cast Zn-Al alloy casting material. By setting the temperature and the temperature at the entrance of the rolling mill and rolling with a lubricant, it is possible to continue rolling after casting, so spray coating at a much lower cost than before. It was possible to manufacture a Zn-Al based alloy wire for use.

[Brief description of drawings]

FIG. 1 is a graph showing changes in yield strength of Zn-Al alloy with temperature.

FIG. 2 Phase diagram of Al—Zn alloy

FIG. 3 is an overall conceptual view of a belt and wheel casting machine (a) and a partial sectional view of a circumferential groove (b).

[Explanation of symbols]

1: Rotary casting wheel 2: Circumferential groove 3: Endless belt 4: Spout 5: Cooling means 6: Cast body

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C22C 18/04 C22C 18/04 C22F 1/16 C22F 1/16 B C23C 4/08 C23C 4/08 // C22F 1 / 00 611 C22F 1/00 611 613 613 625 625 685 685 685A 685Z 694 694A 694B (72) Inventor Teruyuki Nabeta 5443 Kambara, Anbara-gun, Shizuoka Prefecture Alminium Wire Co., Ltd. (72) Inagawa Ishikawa, Tokyo Higashi-Shinagawa 2-chome No. 2-20 F term in Japan Light Metal Co., Ltd. (reference) 4E004 DA01 DA07 KA12 MD05 NB06 NC09 SD01 SE01 4K031 AA01 AB09 CA04

Claims (5)

[Claims] 1. A rotary casting wheel having a circumferential groove on its peripheral surface, and a lid for the circumferential groove, which is made of an alloy melt containing 0.6 to 22.0 mass% of Al and the balance being essentially Zn. In such a manner that the temperature of the casting object becomes 275 ° C. or lower continuously by the belt-and-wheel casting machine equipped with the endless belt that is run in contact with the rotary casting wheel, and when the casting is separated from the casting wheel. Zn-Al for thermal spray coating, characterized in that casting is performed, and subsequently to the casting, the temperature of the material to be rolled at the entrance of the rolling mill is 275 ° C or lower, and rolling is performed at a temperature of 275 ° C or lower while using a lubricant emulsion. Method for producing a base alloy wire rod. 2. The Zn for thermal spray coating according to claim 1, wherein the molten alloy further contains one or more of 0.1 to 3.0 mass% of Si and 0.01 to 1.0 mass% of Mg. -Al
Method for producing a base alloy wire rod. 3. The Zn-Al for thermal spray coating according to claim 1, wherein the lubricant emulsion used during rolling is prepared by mixing rolling oil and water to adjust the oil concentration to 5 to 15% by volume. Method for producing a base alloy wire rod. 4. The cross-section reduction rate during rolling is 60 to 98%.
The spray coating Z according to any one of claims 1 to 3.
A method for manufacturing an n-Al alloy wire. 5. The method for producing a Zn—Al based alloy wire rod for thermal spray coating according to claim 1, wherein after rolling, annealing and cold drawing are subsequently performed.