JPH11197799A - Horizontal continuous casting method of brass and production of brass bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cast slab having excellent surface smoothness and good workability by immediately executing a specific quantity of push-back to pull-out quantity just after executing the pull-out in one cycle of the pull-out pattern. SOLUTION: The push-back is executed so that the push-back quantity (B1 ) to the pull-out quantity (P) becomes 0.01P<=B1 <=0.15P. Just after executing the pull-out at the pull-out quantity (P) in one cycle of the pull-out pattern, it is desirable to immediately execute the push-back so that the push-back quantity (B1 ) to a cast slab thickness (t) becomes 0.01t<=B1 <=0.15t. Further, it is desirable to regulate the pull-out velocity(PV) in one cycle of the pull-out pattern to 30 mm/sec <=PV<=50 mm/sec and to execute the pull-out so that the push-back velocity(BV) becomes 5 mm/sec<=BV<=15 mm/sec. Further, at the time of defining A=L/t for a pull-out pitch (L) and the cast slab thickness (t), in the case of being 12 mm<=t<=20 mm, it is desirable to execute the pull-out with the pull-out pitch (L) satisfying A of 0.4 to 0.6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal continuous casting method suitable for brass for cooling a molten metal in a mold attached to a furnace wall of a holding furnace and continuously drawing an ingot, and the method obtained by the casting method. The present invention relates to a method for producing a brass strip using the obtained ingot.

[0002]

2. Description of the Related Art The conventional horizontal continuous casting method has the advantages that it is used for the production of small quantities of copper alloys in a wide variety of products and can be used to cast thin plates that do not require hot rolling, and that the equipment cost is low. On the other hand, the productivity is low due to the low casting speed, and the surface of the obtained ingot has many irregularities.Therefore, the amount of facing must be increased to remove the oxide film formed on the surface of the ingot. The disadvantage is that the running cost is high, such as poor yield. In particular, in horizontal continuous casting of brass, zinc in brass is oxidized, zinc oxide adheres to the surface, and the unevenness of the surface is further increased, so that the surface smoothness is high and an ingot with good workability can be obtained. There has been an eager need for a horizontal continuous casting method.

[0003] In recent years, in the horizontal continuous casting method described above, a proposal has been made to reduce the density of graphite used for a mold attached to the furnace wall of a holding furnace. According to this proposal, in the early stage of casting, zinc vapor is absorbed and the adhesion of zinc oxide to the surface of the ingot is reduced, and the smoothness of the surface of the brass ingot is improved. Become attached.

On the other hand, the irregularities on the surface of the ingot of brass are not improved even by lowering the density of graphite, but rather tend to increase due to deterioration of the cooling capacity. Attempts have also been made to improve the smoothness by changing the cooling structure provided in the mold, but partial unevenness disappears, but overall unevenness is hardly improved, and workability is improved. The requirement to smooth the surface of the brass ingot while maintaining it has not yet been satisfied.

On the other hand, in the production of brass strips using the horizontal continuous casting method, since the ingot of brass is rolled as it is, if the workability of the ingot is poor, cracks occur during the processing, making rolling impossible. Was. In order to prevent this, annealing is also performed after processing to the extent that cracks do not occur, but in such a case, not only the production efficiency is poor but also a low-working material of single phase alloy is annealed. The so-called "annealing cracks" occurred when cracking occurred. As described above, the production of brass strips using the horizontal continuous casting method has many excellent points, but has many disadvantages, and demands for increasing production efficiency and reducing costs are increasing.

In order to solve these problems, the brass ingot is annealed immediately after casting, and the annealing improves the workability of the ingot, enables high working, and causes "annealing cracks". However, there was a further problem that a large amount of energy was used for annealing immediately after casting, and that time loss was large. Therefore, there has been a demand for a method of producing brass strips that can be produced at low cost while increasing production efficiency while taking advantage of the advantages of the horizontal continuous casting method described above.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a horizontal continuous casting method of brass capable of obtaining an ingot having a high surface smoothness and good workability. Yes, further improve the workability of the ingot obtained by horizontal continuous casting and optimize the processing conditions, and efficiently and inexpensively produce brass strips using the horizontal continuous casting method without generating "annealing cracks" It provides a method.

[0008]

SUMMARY OF THE INVENTION The present inventor has proposed a method of cooling brass in a mold attached to a furnace wall of a holding furnace and continuously drawing ingots to form brass in a horizontal continuous casting. Attention is paid to the continuous casting method in which the ingot is pulled out within one cycle of the ingot withdrawal pattern immediately after the withdrawal in a single cycle without stopping time. It has been found that the above object can be achieved by setting at least one of the thickness and the amount of pushback or the at least one of the draw pitch and the thickness of the ingot to a specific relationship, and has completed the present invention.

Therefore, in order to solve the above-mentioned object, a first embodiment of the present invention is a horizontal continuous casting method of brass for cooling a molten metal in a mold attached to a furnace wall of a holding furnace and continuously drawing an ingot. , Immediately after the withdrawal of the withdrawal amount (P) within one cycle of the withdrawal pattern, the push-back amount (B ₁ ) with respect to the withdrawal amount (P) is 0.01P ≦ B
_The method is characterized by a horizontal continuous casting method of brass that is pushed back so as to satisfy ₁ ≦ 0.15P, and the drawing speed (PV) in one cycle of the drawing pattern is set to 30 mm / sec ≦ PV ≦ 50 mm / sec. , Push back speed (BV) 5m
It is preferable that the drawing is performed so that m / sec ≦ BV ≦ 15 mm / sec.

A second embodiment of the present invention relates to a horizontal continuous casting method of brass for cooling a molten metal in a mold attached to a furnace wall of a holding furnace and continuously drawing an ingot. Immediately after the withdrawal of the withdrawal amount (P) in the cycle, the pushback amount (B ₁ ) with respect to the ingot thickness (t)
Is pushed back so as to satisfy 0.0lt ≦ B ₁ ≦ 0.15t, and the drawing speed (PV) within one cycle of the drawing pattern is 30 mm / sec ≦
PV ≦ 50 mm / sec, push-back speed (BV) is 5 mm
It is preferable that the drawing is performed so as to satisfy the relation: / sec ≦ BV ≦ 15 mm / sec.

Further, a third embodiment of the present invention is directed to a horizontal continuous casting method of brass for cooling a molten metal in a mold attached to a furnace wall of a holding furnace and continuously drawing an ingot. When the drawing pitch (L) and the ingot thickness (t) are A = L / t in the cycle, 12 mm ≦ t ≦ 20 m
In the case of m, the method is characterized by a horizontal continuous casting method of brass drawn at a draw pitch (L) having a relationship of 0.40 ≦ A ≦ 0.60.

In a fourth embodiment of the present invention, the ingot obtained by the above-mentioned horizontal continuous casting method has a reduction in area of 50 to 9%.
It is characterized by a method of producing annealed brass strip after 2% processing.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the horizontal continuous casting method of brass, the present inventor immediately pushes back without any stop time immediately after drawing in one cycle of the drawing pattern of the brass ingot, that is, the drawing-push-back-stop-push-stop cycle. By performing one or more of the following conditions in combination, the seam of melt solidification in each cycle is crushed and the surface becomes smooth, and the solidified shell is pressed against the inner surface of the mold. It has been found that the solidification is promoted and the ingot surface, which is generated by the adhesion of zinc, is prevented from peeling to the inner surface of the mold.

That is, immediately after the withdrawal of the withdrawal amount (P) is performed within one cycle of the withdrawal pattern, the push-back amount (B ₁ ) with respect to the withdrawal amount (P) is 0.01P.
It is pushed back and cast to satisfy ≦ B ₁ ≦ 0.15P. Push-back amount (B ₁ ) against pull-out amount (P) within one cycle
Is less than 0.01P, crushing of the solidification seam, insufficient pressing of the solidified shell against the inner surface of the mold, the ingot surface does not become smooth, and unevenness due to the adhesion of zinc occurs,
On the other hand, if the push-back amount (B ₁ ) exceeds 0.15P, the crushing becomes excessive, the seam becomes convex, and wrinkle-like irregularities on the surface of the ingot increase.

Further, in the present invention, immediately after the withdrawal amount (P) is withdrawn in one cycle of the withdrawal pattern of the brass ingot, the pushback amount (B ₁ ) with respect to the ingot thickness (t) is changed. It is cast back by pushing back so that 0.0lt ≦ B ₁ ≦ 0.15t. When the pushback amount (B ₁ ) is less than 0.0lt with respect to the ingot thickness (t), the pushback effect is insufficient and the surface of the ingot is not smooth, and unevenness due to the adhesion of zinc occurs. On the other hand, if the push-back amount (B ₁ ) exceeds 0.15 t, the seam becomes convex, and wrinkle-like irregularities on the surface of the ingot increase.

In the above casting method, the drawing speed (PV) in one cycle of the drawing pattern is set to 30 mm / sec ≦ PV ≦ 50 mm / sec, and the pushing back speed (BV) is set to 5 m.
It is preferable that the drawing is performed so that m / sec ≦ BV ≦ 15 mm / sec. The withdrawal speed (PV) within one cycle is 30m
If it is less than m / sec, the flow of the molten metal into the mold is not sufficient, and wrinkle-like unevenness due to the adhesion of zinc occurs on the surface of the ingot,
On the other hand, if the drawing speed (PV) exceeds 50 mm / sec, the drawing resistance increases and cracks occur in the ingot. If the push-back speed (BV) is less than 5 mm / sec, solidification proceeds before the seam is crushed and the crushing effect becomes insufficient, and wrinkle-like unevenness due to the adhesion of zinc occurs. When the return speed (BV) exceeds 15 mm / sec, the solidified shell falls down into the molten metal and wrinkles occur at the joint of the molten metal.

Further, in the present invention, when the drawing pitch (L) and the ingot thickness (t) are A = L / t within one cycle of the drawing pattern of the brass ingot, 12 mm ≦ t ≦ 2.
In the case of 0 mm, it is necessary to draw and cast at a draw pitch (L) having a relationship of 0.40 ≦ A ≦ 0.60, and casting under these conditions results in a fine cast structure and workability. And the subsequent high-reduction-rate processing can be performed without annealing the ingot.

The reason for the above conditions is that when the ratio (A) of the drawing pitch (L) and the ingot thickness (t) is less than 0.40, the workability of the ingot is good, but the casting speed is low. If the ratio (A) exceeds 0.60, the cast structure becomes coarse and the workability deteriorates. This is because it becomes difficult to process the same. Even if the ratio (A) of the drawing pitch (L) to the ingot thickness (t) is set to 0.40 to 0.60, if the ingot thickness (t) is less than 12 mm, not only swelling occurs in the ingot but also the production is remarkable. 20mm
If it exceeds, the amount of cold rolling increases and the processing cost up to the product increases, so the ingot thickness (t) needs to be kept in the range of 12 mm to 20 mm.

The ingot of brass obtained by the above-mentioned horizontal continuous casting method is processed at a surface reduction rate of 50 to 92%,
Subsequent annealing makes it possible to produce brass strips having a uniform recrystallized structure without causing "annealing cracks". If the area reduction rate is less than 50%, not only annealing performed later will cause “annealing cracks” but also a mixed grain structure in which coarse crystals are mixed.
When processing is performed to a surface reduction rate exceeding 2%, not only energy required for processing is required but also defects such as edge cracks are generated.

[0020]

Example 1 65/35 brass was cast by a horizontal continuous casting apparatus using a graphite mold under the following casting conditions 1-6. At this time, the state of the surface of the ingot was observed by changing the amount of drawing (P) and the amount of pushing back (B ₁ ) within one cycle, and the results are shown in Table 1.

[0021]

[Table 1]

As is evident from Table 1, it can be seen that in the embodiment of the present invention, an ingot having a smooth surface is obtained, while in the comparative example, irregularities are generated on the surface of the ingot.

Casting conditions 1. Ingot size: 16 mm (t) x 650 mm (w) Lead pattern: withdrawn amount (P) - the push-back amount _{(B 1)} - stop time _{(S 1)} - the push-back amount _{(B 2)} - stop time _(S 2) However, the stop time _{(S 1)} includes a P varied by the setting of B _{1, (S 2)} was set to 0.1 seconds. 3. 3. Casting speed: 200 mm / min. Pull-out pitch (L): 9 mm [Therefore, the push-back amount (B ₂ ) is P-9 mm−the push-back amount (B ₁ ). The same applies to the following embodiments]. 5. Withdrawal speed (PV): 43 mm / sec Push-back speed (BV): 10 mm / sec

Example 2 65/35 brass was cast by a horizontal continuous casting apparatus using a graphite mold under the following casting conditions 1-7. At this time, the state of the surface of the ingot was observed by changing the thickness (t) of the ingot and the pushback amount (B ₁ ) within one cycle, and the results are shown in Table 2.

[0025]

[Table 2]

As is clear from Table 2, it can be seen that in the embodiment of the present invention, an ingot having a smooth surface is obtained, whereas in the comparative example, irregularities are generated on the surface of the ingot.

Casting conditions 1. Ingot width: 650 mm 2. Withdrawal amount (P): 13 mm Lead pattern: withdrawn amount (P) - the push-back amount _{(B 1)} - stop time _{(S 1)} - the push-back amount _{(B 2)} - stop time _(S 2) However, the stop time _{(S 1)} and _{(S 2} Is the same as in the first embodiment. 4. 4. Casting speed: 200 mm / min 6. Drawing pitch (L): 9 mm 7. Withdrawal speed (PV): 43 mm / sec Push-back speed (BV): 10 mm / sec

Example 3 65/35 brass was cast by a horizontal continuous casting apparatus using a graphite mold under the following casting conditions 1-6. At this time, the state of the surface of the ingot was observed by changing the drawing speed (PV) and the pushing back speed (BV) within one cycle, and the results are shown in Table 3.

[0029]

[Table 3]

As is clear from Table 3, it can be seen that in the embodiment of the present invention, an ingot having a smooth surface is obtained, whereas in the comparative example, irregularities are generated on the surface of the ingot.

Casting conditions 1. Ingot size: 16 mm (t) x 650 mm (w) 2. Withdrawal amount (P): 13 mm Lead pattern: withdrawn amount (P) - the push-back amount _{(B 1)} - stop time _{(S 1)} - the push-back amount _{(B 2)} - stop time _(S 2) However, the stop time _{(S 1)} and _{(S 2} Is the same as in the first embodiment. 4. 4. Push-back amount (B ₁ ): 1.0 mm 5. Casting speed: 200 mm / min Drawing pitch (L): 9mm

Example 4 Using a graphite mold under the following casting conditions 1 to 7, the ingot thickness (t), the drawing pitch (L) and the casting speed were changed as shown in Table 4 to obtain 65/35. Brass was cast by a horizontal continuous casting apparatus. The condition of the ingot surface at this time was observed and evaluated, and the results are shown in Table 4.

[0033]

[Table 4]

As is clear from Table 4, in the embodiment of the present invention, a good ingot without defects on the surface can be obtained at a high casting speed, whereas in the comparative example, if the casting speed is increased, the ingot can be obtained. It can be seen that defects are generated on the surface and that casting speed must be significantly reduced in order to prevent casting defects.

Casting conditions 1. Ingot width: 650 mm 2. Withdrawal amount (P): L + 4 mm Lead pattern: withdrawn amount _{(P 1)} - the push-back amount (B
₁₎ - the stop time _{(S 1)} - the push-back amount _{(B 2)} - stop time _(S 2) However, the stop time _{(S 1)} and _{(S 2)} are the same as in Example 1. 4. Casting speed: 500-1,000 kg / hour 5. Push-back amount (B ₁ ): 1.0 mm 6. Withdrawal speed (PV): 43 mm / sec Push-back speed (BV): 10 mm / sec

Example 5 The ingot thickness (t) and the drawing pitch (L) were changed as shown in Table 1 using a graphite mold under the following casting conditions 1 to 7, and 65/35 brass was used as a horizontal die. It was cast by a continuous casting device. The obtained ingot was subjected to 1 mm face milling on one side, and then rolled at various reduction rates as shown in Table 5. Further, annealing was performed at 530 ° C. for 4 hours, pickling was performed, and the condition of the surface of the brass strip was observed.
Are shown together.

[0037]

[Table 5]

As is clear from Table 5, in the present invention, a good brass strip was obtained without any defect on the surface, whereas in the comparative example, a defect was generated on the surface of the brass strip.

Casting conditions 1. Ingot width: 650 mm 2. Withdrawal amount (P): L + 4 mm Lead pattern: withdrawn amount (P) - the push-back amount _{(B 1)} - stop time _{(S 1)} - the push-back amount _{(B 2)} - stop time _(S 2) However, the stop time _{(S 1)} and _{(S 2} Is the same as in the first embodiment. 4. 4. Push-back amount (B ₁ ): 1.0 mm 5. Casting speed: 900 kg / hour 6. Withdrawal speed (PV): 43 mm / sec Push-back speed (BV): 10 mm / sec

[0040]

As described above, according to the present invention, it is possible to provide a horizontal continuous casting method of brass capable of obtaining an ingot having high surface smoothness and good workability, and a casting method obtained by the horizontal continuous casting. It is possible to provide a method for efficiently and inexpensively manufacturing brass strips by using a horizontal continuous casting method without improving the workability of a lump and optimizing the processing conditions, and without causing “annealing cracks”.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C22F 1/00 625 C22F 1/00 625 681 681 685 685Z 686 686A 694 694A

Claims (5)

[Claims] In a horizontal continuous casting method of brass for cooling a molten metal in a mold attached to a furnace wall of a holding furnace and continuously drawing an ingot, a drawing amount (P) within one cycle of a drawing pattern is determined. Immediately after the withdrawal is performed, the push-back amount (B ₁ ) with respect to the withdrawal amount (P) is 0.01P ≦ B ₁ ≦
A horizontal continuous casting method of brass, characterized by pushing back to 0.15P. 2. A horizontal continuous casting method of brass for cooling a molten metal in a mold attached to a furnace wall of a holding furnace and continuously drawing an ingot, wherein a drawing amount (P) in one cycle of a drawing pattern is determined. Immediately after the drawing is performed, the pushback amount (B ₁ ) with respect to the ingot thickness (t) is 0.0lt ≦ B ₁ ≦ 0.15.
A continuous continuous casting method of brass, characterized by pushing back to t. 3. A drawing speed (PV) within one cycle of the drawing pattern, wherein 30 mm / sec ≦ PV ≦ 50 mm /
And the push-back speed (BV) is 5 mm / sec ≦ BV ≦ 15
The horizontal continuous casting method of brass according to claim 1 or 2, wherein the brass is drawn out at a rate of mm / sec. 4. In a horizontal continuous casting method of brass for cooling a molten metal in a mold attached to a furnace wall of a holding furnace and continuously drawing an ingot, a drawing pitch (L) within one cycle of a drawing pattern. When the ingot thickness (t) is A = L / t,
When 12 mm ≦ t ≦ 20 mm, 0.40 ≦ A ≦ 0.
A horizontal continuous casting method for brass, wherein drawing is performed at a drawing pitch (L) having a relationship of 60. 5. An ingot obtained by the horizontal continuous casting method according to claim 4, which is subjected to a reduction in area of 50 to 92%.
A method for producing brass strips, characterized by annealing.