JPH07188770A - Production of surface treated original sheet having tempering degree by rapid heating annealing - Google Patents

Abstract

PURPOSE:To produce a steel sheet for a vessel having l to 3 tempering degree and excellent in earing properties. CONSTITUTION:The soft steel sheet for a vessel in which excellent earing properties can be secured even if rapid heating annealing is executed at >=100 deg.C/s and having l to 3 tempering degree even if the same rapid heating annealing is executed can be produced by executing componental regulation to any of (1) C: <=30ppm and N:<=50ppm, (2) C: <=30ppm, N: <=80ppm and B: 0.4 to 2.5 by B/N (atomic weight ratio) Thus, the steel having <1% earing ratio can be produced by the surface treated original sheet of T-1 to T-3, and its industrial value is high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a hardness level of 1 to 3 (hereinafter T-1 and T-, respectively) in terms of temper degree of a surface-treated original plate to which surface treatment such as tin plate and tin-free steel is applied.
Write 3. ) A method for producing a surface-treated original plate having excellent earring properties by continuous annealing.

[0002]

2. Description of the Related Art The DWI method is used for processing a can body of a two-piece can.
(Draw and Wall Ironed) and DRD method (Draw and Red Ironed)
Raw) etc., but each is characterized by making a two-piece can barrel on a cup (to be precise, a body and bottom are integrated) from a blank plate on a disk by processing including drawing. At that time, due to the anisotropy of workability, it is known that the height of the upper end of the body after the can body is not constant along the circumferential direction, and the upper end of the body after processing is wavy. .
The convex portion on the upper end of the body where the earrings are formed is called an ear or an ear, and the degree of the earring is generally expressed by the earring rate.

The earring rate is a value obtained by dividing the difference between the average height of the peaks and the average height of the valleys by the average of the heights of the valleys, and expressing the percentage by the percentage. small. If the earrings are large, the DRD cans will be trimmed to align the heights of the tops of the cans, resulting in yield loss.For DWI cans, the material in the valley between the ears during DWI processing after cup molding is Causes troubles such as being pulled and breaking, or tearing the ear portion, which adversely affects the productivity of the user. Therefore, users strongly desire a material with an earring rate of 1% or less.

Conventionally, a surface-treated original plate (steel plate for a container) to which surface treatment such as tin plate and tin-free steel is applied is heated at a heating rate of 10 to 40 ° C./s (second) in order to recrystallize the material. And soak for 20 to 40 seconds at 600 to 700 ° C, cool to 500 ° C at 10 to 20 ° C / s, and 20 to 40
It was manufactured in a continuous annealing furnace having an annealing time of about 2 minutes such that it was cooled to room temperature at ℃ / s. However, this 10
At a low heating rate of 40 ° C./s, the orientation with high strain energy preferentially causes recrystallization, so that anisotropy occurs in the texture and an earring rate of about 3% occurs.

Therefore, the inventors of the present invention investigated the relationship between the earring and the heating rate during continuous annealing. When rapid heating annealing at 100 ° C./s or more was performed, recrystallization occurred instantaneously. It has been found that the priority is reduced and the earring rate can be greatly reduced to 1% or less. Regarding this rapid heating and annealing, for example, the temperature rising rate, the soaking temperature, and the cooling rate are specified, and a method for producing a low-carbon steel sheet without kink and Luders wire is disclosed. There is 21155 gazette, but Japanese Patent Publication Sho 4
No. 6-19781 relates to a very hard material having an HR30T of 72 or more and a temper degree of 6 or more, and it is impossible to manufacture the temper degrees T-1 to T-3. Further, Japanese Patent Publication No. 36-21155 discloses the levels of T-2 and T-5, but it must be wound at 200 to 300 ° C. during annealing, which causes a problem of oxidation. Further, neither of the inventions mentions any relation between rapid heating and earrings.

[0006]

SUMMARY OF THE INVENTION According to the present invention, T-1 to T-1 to which surface treatment such as tin plate and tin-free steel is applied.
A method for producing a surface-treated original plate by continuous annealing which is T-3 and has an earring rate of 1% or less required by a can-making maker.

[0007]

In order to solve the above problems, the inventors of the present invention comprehensively studied the content of components, hot rolling conditions, cold rolling conditions, and continuous annealing conditions, and made the manufacturing method of the present invention. I found it. That is, the gist of the present invention is as follows. (1)% by weight, C: 0.0030% or less, Mn:
0.05-0.60%, P: 0.001-0.025
%, S: 0.001 to 0.025%, sol.Al: 0.
012 to 0.120%, N: ≤ 0.0050%, T.I.
O: ≤ 0.0070%, the steel slab consisting of the balance unavoidable impurities and iron is heated and hot-rolled under normal hot-rolling conditions to form a hot-rolled steel strip, which is then cold-rolled. , 650-85 at 100-2000 ℃ / s in continuous annealing
Recrystallization annealing is performed by heating to 0 ° C and cooling to room temperature,
A method for producing a surface-treated original plate having a tempering degree of 1 to 3 with excellent earring properties, which is characterized by performing temper rolling of 0.5 to 5.0%. (2) Steel billet component in% by weight, C: 0.0030% or less, Mn: 0.05-0.60%, P: 0.001-
0.025%, S: 0.001-0.025%, sol.
Al: 0.012 to 0.120%, N: ≤ 0.008
0%, B: B / N (atomic weight ratio) 0.4 to 2.5,
T. O: ≤ 0.0070%, the balance being unavoidable impurities and iron. The method for producing a surface-treated original plate according to item (1), which has an excellent degree of tempering and has a temper degree of 1 to 3.

The present invention will be described in detail below. In order to solve the above-mentioned problems, the present inventors comprehensively studied the component content, hot rolling conditions, cold rolling conditions, and continuous annealing conditions for the manufacturing method. As a result, it was found that there are two main points described below. The first point is that, as described above, by increasing the heating rate during continuous annealing, recrystallization is instantaneously caused and the anisotropy is reduced, so that the earring can be reduced. It was found that the heating rate during continuous annealing should be 100 ° C./s or more in order to suppress the earring rate to 1% or less.

The second point is that in order to obtain the temper degree of T-1 to T-3, it is necessary to take the following component system, hot rolling condition and continuous annealing condition together with the rapid heating at the time of annealing. I found that there is. That is, the present invention is a method whose main condition is to set the C content to 0.0030% or less. When the C content exceeds 0.0030%, the adverse effect of C becomes too large and the fluting property deteriorates. Therefore, it is necessary to regulate the C content. Also B to B /
When N (atomic weight ratio) is made to be 0.4 to 2.5, N is coarsely precipitated as BN and the adverse effect is mitigated, so that the N content is ≦ 0.0080%, and the regulation can be significantly mitigated. it can.

The manufacturing conditions will be described in more detail below. As described above, C is an element that greatly affects the fluting property, and is a solid solution C after recrystallization annealing during super rapid heating.
It is an atom that greatly influences the amount, and the amount of solute C increases as the C content increases, so that the fluting property deteriorates. C
If the content exceeds 0.0030%, the fluting property exceeds the limit, so the upper limit of the C content is set to 0.
It was set to 0030%.

Mn, P, S and sol.Al not only harden the material but also increase the corrosion resistance of the steel sheet if these elements increase, so the upper limit of each element is 0.060%, 0.025%, 0.025%, 0.12
It was set to 0%. The lower limit of each of Mn, P, and S was set as the lower limit within the range obtained by a usual manufacturing method. Also, so
When the Al content is less than 0.012%, the deoxidation is insufficient, so that the T. Since the O content becomes high and the content cannot be 0.0070% or less, at least 0.012% is necessary, and the lower limit sol.Al content is set to 0.012%.

In the first invention, when the N content exceeds 0.0050%, the solid solution hardening does not allow the production of a soft steel sheet of T-3 or less. Therefore, the upper limit of the N content is 0.0050%. And In addition, in the second invention, by adding B, N is changed to B
Since it is fixed as N, a soft material can be obtained even if the N content increases, but if the N content exceeds 0.0080%, the precipitation amount of BN becomes too large and the material becomes hard, and T-1
Since the hardness of ~ T-3 cannot be obtained, 0.0080%
Was set as the upper limit. It should be noted that the lower the N content, the softer the steel sheet is obtained, so there is no need to regulate the lower limit value.

T. If the O content exceeds 0.0070%, bubbles are generated in the vicinity of the surface layer of the slab, surface scratches on the plating original plate increase, and good products cannot be obtained.
The upper limit was 0.0070%. The lower limit is not regulated because it does not need to be regulated.

In the second invention, B is B: B / N (atomic weight ratio) of 0.4 to 2.5 so that N is converted to B.
It is possible to coarsely precipitate as N to alleviate the adverse effect and significantly alleviate the regulation of the N content, so that ≦ 0.0080%. When B is B / N (atomic weight ratio) of less than 0.4, N is replaced by B
Coarse precipitation cannot be performed as N, and B / N
If the (atomic weight ratio) exceeds 2.5, the amount of solid solution B will be too large and the material will be hardened, and T-1 to T-3 cannot be obtained. Therefore, B / N (atomic weight ratio) is 0.4 to 2. Restricted to 5.

The hot rolling conditions do not have to be particularly restricted, and ordinary hot rolling conditions may be used. In the method of the first invention, the adverse effect of N can be completely eliminated by performing high temperature winding during hot rolling, and a softer steel plate can be obtained. Therefore, high temperature winding may be performed as necessary. Furthermore, the heating conditions for hot rolling do not need to be particularly restricted and may be those that are normally performed, but to obtain a softer steel plate, 1150 ° C.
The following heating temperature (referred to as SRT) is preferable. The pickling and cold rolling conditions do not need to be particularly regulated and may be normal conditions.

As described above, if the heating and annealing rate during continuous annealing is less than 100 ° C., the earring rate exceeds 1%,
Since the excellent earring property cannot be ensured, the lower limit of the heating / annealing rate was 100 ° C. Also, the heating and annealing rate is 2
If it exceeds 000 ° C / s, the heating rate is too fast, and the control of the temperature reached by heating becomes unstable, and it becomes difficult to obtain stable quality. Therefore, the upper limit was 2000 ° C / s. If the annealing temperature during continuous annealing is less than 650 ° C., recrystallization is not completed, so 6
The lower limit was 50 ° C. Further, if it exceeds 850 ° C, the steel plate is softened and easily stretched to deteriorate the sheet passing property.
Was set as the upper limit.

As for the soaking time during continuous annealing, even if there is no soaking time in ultra-rapid heating annealing, sufficient recrystallization and grain growth occur and a hardness of T-1 to T-3 is obtained, so soaking. There is no need to regulate the lower limit of time. The upper limit of the soaking time does not have to be particularly restricted, but it is preferably 3 seconds or less in order to make the equipment compact. With regard to the cooling rate during continuous annealing, the steel of this component system does not particularly affect the material quality, so that it is not necessary to specifically limit it.

Temper rolling is necessary to improve fluting property, and good fluting can be obtained at 0.5% or more. Therefore, it is necessary to perform temper rolling at least 0.5% or more. is there. If the temper rolling ratio exceeds 5.0%, the material becomes hard and the hardness of T-1 to T-3 is obtained, so the upper limit of the temper rolling ratio was set to 5.0%.

[0019]

EXAMPLES The effects of the present invention will be described below with reference to examples. The components shown in Table 1 and hot rolling conditions were used to produce 2.5 mm hot-rolled steel strips, which were cold-rolled at a cold rolling rate of 90% to 0.25 mm. Under the conditions of the continuous annealing heat cycle shown in Table 2, continuous annealing and temper rolling were performed to obtain a surface-treated original plate. Table 2 shows the results of measurement of hardness HR30T, fluting property and earrings of this surface-treated original plate. For the evaluation of the earring property, cup forming was performed by a drawing machine in a laboratory, and the value obtained by dividing the difference between the average height of the ridges and the average height of the valleys by the average height of the valleys was shown as a percentage. Since there is almost no difference between the earring value obtained in the present experiment and the earring value obtained by the user, those having an earring value of 1% or less obtained in the present experiment were accepted. For fluting, after heat treatment equivalent to reflow, bending with three rolls,
The fluting property was investigated.

[0020]

[Table 1]

[0021]

[Table 2]

Steels A and B are steels having the composition of the first invention, steel C is steel having a composition within the scope of the second invention, and steel D is a manufacturing condition outside the scope of the present invention. Samples 1, 2, 3, 4, 5 and 6 are examples of the present invention, and all have hardness ranges of T-1 to T-3 (HR30T = 58 ± 3 to 61 ± 3) and have good fluting properties. The earring rate is also good at 1% or less. Sample 4 is an example in which the temper rolling ratio is as large as 4.0%, and the fluting property is particularly excellent. As shown in Tables 1 and 2, Sample 6 was a second sample containing mainly 0.0037% B.
It is an example of the invention. It can be seen that a soft surface-treated original plate can be obtained even when the N content is as high as 0.0056%.

Sample 7 is a comparative example in which the C content of the first invention is high and deviates, and it can be seen that the fluting property is poor. Samples 8 and 9 are examples in which the annealing heating rate deviates from the lower limit of the present invention. The earring rate is over 1%, which shows that the earring property is poor.

[0024]

The present invention has been described in detail above. According to the present invention, it is possible to produce a steel having an earring rate of less than 1% and an excellent earring property with the surface-treated original plate of T-1 to T-3. It is possible and its industrial value is great.

[Brief description of drawings]

FIG. 1 is a diagram showing an annealing cycle.

Claims (2)

[Claims] 1. By weight%, C: 0.0030% or less, Mn: 0.05-0.60%, P: 0.001-0.025%, S: 0.001-0.025%, sol.Al: 0.012 to 0.120%, N: ≤ 0.0050%, T.S. O: ≦ 0.0070%, the steel slab consisting of the balance unavoidable impurities and iron is heated and hot-rolled under normal hot-rolling conditions, and as a hot-rolled steel strip, cold-rolled, and then , 650-8 at 100-2000 ℃ / s in continuous annealing
Recrystallization annealing is performed by heating to 50 ° C. and cooling to room temperature,
A method for producing a surface-treated original plate having a tempering degree of 1 to 3 with excellent earring properties, which is characterized by performing temper rolling of 0.5 to 5.0%. 2. A steel billet component in% by weight, C: 0.0030% or less, Mn: 0.05 to 0.60%, P: 0.001 to 0.025%, S: 0.001 to 0 .025%, sol.Al: 0.012 to 0.120%, N: ≤ 0.0080%, B: B / N (atomic weight ratio) 0.4 to 2.5, T.I. O: ≤ 0.0070%, the balance being unavoidable impurities and iron. The method for producing a surface-treated original plate according to claim 1, wherein the tempering degree is excellent and the tempering degree is 1-3.