KR20090068906A

KR20090068906A - Strong steel sheet for tinning and manufacturing method thereof

Info

Publication number: KR20090068906A
Application number: KR1020070136710A
Authority: KR
Inventors: 김재익; 김종화
Original assignee: 주식회사 포스코
Priority date: 2007-12-24
Filing date: 2007-12-24
Publication date: 2009-06-29

Abstract

A tin plate is provided to be manufactured as a soft tin plate having temper grade T1 by having excellent aging resistance and workability, and to be manufactured as a tin plate having all-temper grade without additional secondary rolling. A tin plate contains less than 0.004 weight percent carbon(C), 0.2~0.8 weight percent manganese(Mn), less than 0.05 weight percent silicon(Si), less than 0.02 weight percent sulfur(S), 0.02~0.10 weight percent aluminum(Al), 0.002~0.006 weight percent nitrogen(N), 0.1~0.3 weight percent molybdenum(Mo), 0.04~0.09 weight percent zirconium(Zr), 0.001~0.003 weight percent boron(B), and iron(Fe) and impurities, wherein the atomic ratio of the zirconium(Zr) and the carbon(C) exists within the range of 1.3~3.5. A manufacturing method of a tin plate comprises the steps of manufacturing steel for a tin plate(S1), hot-rolling and reeling the steel(S2), and annealing the rolled material(S3).

Description

Tin-plated disc and its manufacturing method {STRONG STEEL SHEET FOR TINNING AND MANUFACTURING METHOD THEREOF}

The present invention relates to a tin-plated master plate and a method of manufacturing the same, and more particularly, to a tin-plated master plate having a precursor quality excellent in workability and a method of manufacturing the same.

Tin-plated discs, which are used for cans, are usually thin in thickness and are classified by temper grade measured by HR30T, the Rockwell surface hardness. To make cans for the storage of contents with tin-plated discs, tin (Sn), etc. should be plated on the surface of the disc to give corrosion resistance, cut to a certain size, and processed into round or square. The method of processing a container is a method in which the container is processed without welding, such as a two-piece can consisting of a lid and two parts of a body, and the can is composed of a body and an upper end. , And a method of fastening the body by welding or joining, such as a three-piece can consisting of three parts of the bottom bottom. The main use of the soft tin-plated master disc having T3 (54 to 60 based on HR30T value) grade is used in the part where workability is required, and also T4 (58 to 64 based on HR30T value) to T6 (HR30T based value 67). The hard tin-plated disc of grade 73) is widely used in areas where properties such as the body of the can, the end and the bottom, and the like that can withstand the internal pressure by the contents are required.

Rolling quality tin-plated disc means the tin-plated disc which secured the material of the grade T1-class T6 as one material by changing manufacturing conditions, such as hot rolled and cold rolled. In order to manufacture the precursor quality as a single material, it is important to efficiently manufacture a soft tin plated disc. Soft tin-plated discs, which are used for containers requiring high workability, have been mainly manufactured by annealing. However, in the case of the ordinary annealing method, there is a problem that the productivity of the annealing process takes a long time and the material is uneven. Therefore, in recent years, even in the continuous annealing method, the production cost is low, the material is uniform, and the flatness and surface properties are excellent. Is being manufactured.

In Japanese Laid-Open Patent Application No. 2-118027, as a method of manufacturing a rolled tin-plated fine-grained plate, a tin-plated plate of a crude-grade T1 grade is produced by ordinary annealing or continuous annealing, followed by rolling in a step of skin pass mill (SPM). It is described that it can be produced by obtaining a predetermined quality while gradually increasing the rate. However, in order to apply strong reduction in the temper rolling step, a separate secondary rolling facility is required. In addition, there is a problem that the cost is rapidly increased due to the increase in processing cost by using such a facility, it is difficult to see an efficient manufacturing method.

The present invention provides a tin-plated disc which is excellent in workability and can exhibit characteristics of roll quality.

The present invention also provides a method for producing a tin-plated disc.

However, the technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, according to one embodiment of the present invention, carbon (C) 0.004% by weight or less, manganese (Mn) 0.2 to 0.8% by weight, silicon (Si) 0.05% by weight or less, sulfur (S) 0.02 weight % Or less, 0.02 to 0.10% by weight of aluminum (Al), 0.002 to 0.006% by weight of nitrogen (N), 0.1 to 0.3% by weight of molybdenum (Mo), 0.04 to 0.09% by weight of zirconium (Zr), and 0.001 to 0.003 of boron (B) It provides a tin-plated disc containing the weight percent, the balance of Fe and impurities, wherein the atomic ratio of zirconium (Zr) / carbon (C) is in the range of 1.3 to 3.5.

According to another embodiment of the present invention, carbon (C) 0.004% by weight or less, manganese (Mn) 0.2 to 0.8% by weight, silicon (Si) 0.05% by weight or less, sulfur (S) 0.02% by weight or less, aluminum (Al) ) 0.02 to 0.10 wt%, nitrogen (N) 0.002 to 0.006 wt%, molybdenum (Mo) 0.1 to 0.3 wt%, zirconium (Zr) 0.04 to 0.09 wt%, boron (B) 0.001 to 0.003 wt%, balance Fe And producing impurities in the tin-plated disc steel, wherein the zirconium (Zr) / carbon (C) atomic ratio is present in the range of 1.3 to 3.5. Hot rolling and winding the steel; And it provides a method for producing a tin-plated disc comprising the step of annealing the winding result.

Other details of the embodiments of the present invention are included in the following detailed description.

The tin-plated disc having a specific composition according to the present invention can be produced as a soft tin-plated disc of fine T1 grade with excellent aging resistance and processability, and can be produced as a tin-plated tin plate without additional secondary rolling.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented by way of example, and the present invention is not limited thereto, the present invention is defined only by the scope of the claims to be described later.

Tin plated disc according to an embodiment of the present invention, carbon (C) 0.004% by weight or less, manganese (Mn) 0.2 to 0.8% by weight, silicon (Si) 0.05% by weight or less, sulfur (S) 0.02% by weight or less, aluminum (Al) 0.02 to 0.10 wt%, nitrogen (N) 0.002 to 0.006 wt%, molybdenum (Mo) 0.1 to 0.3 wt%, zirconium (Zr) 0.04 to 0.09 wt%, boron (B) 0.001 to 0.003 wt%, glass Negative Fe and impurities, and the atomic ratio of zirconium (Zr) / carbon (C) is present in the range of 1.3 to 3.5.

Hereinafter, the components and the composition of the tin-plated disc of the present invention will be described in detail.

Carbon is preferably added at 0.004% by weight or less. In the said range, after annealing, the material of grade T1 (based on HR30T value, 46-52) grade can be ensured stably. However, when the added amount of carbon exceeds 0.004% by weight, it is not preferable to obtain a T1 grade material after continuous annealing due to the solid solution strengthening effect, which may adversely affect the aging of steel.

Manganese is preferably added at 0.2 to 0.8% by weight. Red manganese can be prevented when manganese is added in an amount of 0.2% by weight or more. However, when the amount of manganese exceeds 0.8% by weight, the hardenability is increased to form a hard two-phase structure such as bainite, resulting in unstable strength, and micro-segregation occurs to deteriorate formability. It is not desirable because it can be a factor.

Silicon is preferably added at 0.05% by weight. Silicon tends to bond with oxygen to form an oxide layer on the surface of the steel sheet, and when it exceeds 0.05% by weight, it can lower the tin plating property and lower the corrosion resistance, which is undesirable.

Sulfur is preferably added at 0.02% by weight or less. Sulfur is not preferred because some of it tends to combine with manganese in the steel to form manganese-sulfide-based precipitates.

Aluminum is preferably added at 0.02 to 0.1% by weight, more preferably 0.03 to 0.1% by weight. Aluminum has the effect of preventing material deterioration by deoxidizer and aging in aluminum-kilted steel, and this effect can be realized when adding at least 0.02% by weight of aluminum. However, when the addition amount of aluminum exceeds 0.1% by weight, the saturation of the deoxidation effect and the surface inclusions such as aluminum oxide (Al ₂ O ₃ ) is rapidly increased by the excess aluminum content to deteriorate the surface properties of the hot rolled material This is undesirable.

Nitrogen is preferably added at 0.002 to 0.006% by weight. Nitrogen is a representative invasive reinforcing element, and when added in an amount of 0.002% by weight or more, it is possible to secure a target quality. However, when the added amount of nitrogen exceeds 0.006% by weight, material degradation due to aging occurs rapidly, and the burden of denitrification process increases in the steelmaking step, which is not preferable because there is a problem that deterioration of steelmaking workability.

Molybdenum is preferably added at 0.1 to 0.3% by weight. Molybdenum has the effect of improving the recovery properties of the steel, this effect can be realized when adding at least 0.1% by weight of molybdenum. However, when the addition amount of molybdenum is less than 0.1%, it is difficult to obtain an effect of improving recovery characteristics, and thus it is difficult to produce tin-plated master plates having a precursor quality. In addition, if the content exceeds 0.3% by weight, an increase in manufacturing cost due to the excessive use of expensive molybdenum and a hard second phase may be formed, which may cause problems that make it difficult to secure a target quality.

Zirconium is preferably added at 0.04 to 0.09% by weight. Zirconium has the effect of securing workability during hot rolling, improving recovery characteristics, and suppressing deterioration of workability due to aging, and this effect can be realized when at least 0.04% by weight of zirconium is added. However, when the addition amount of zirconium exceeds 0.09% by weight, it is not preferable because there is a problem that acts as a factor to deteriorate the annealing characteristics of the ultrathin material by increasing the recrystallization temperature of the steel rather rapidly.

Boron is preferably added at 0.001 to 0.003% by weight. Boron has the effect of improving the rolling workability and recovery properties, this effect can be realized when adding a minimum amount of boron 0.001% by weight. However, when the addition amount of boron exceeds 0.003% by weight, it causes a material hardening, which is not preferable because it is difficult to secure the target quality.

Moreover, it is preferable that the atomic ratio of zirconium (Zr) / carbon (C) exists in the range of 1.3-3.5. In the above range, there is an effect of improving the moldability and recovery characteristics of the material through securing the aging resistance. However, if the atomic ratio is less than 1.3, the residual amount of solid solution carbon may increase, causing deformation aging, which may cause processing defects such as stretcher-strain during molding. It is not preferable because it is difficult to manufacture a plated disc. In addition, when the atomic ratio exceeds 3.5, there is a problem that the recrystallization temperature of the ultrathin material rises rapidly, which lowers the annealing workability, which is not preferable.

According to another embodiment of the present invention, there is provided a method of manufacturing a plate for tin plating. 1 is a view showing a manufacturing process of a tin plating plate according to an embodiment of the present invention, for example, looks at in detail the manufacturing method of the tin plating plate.

S1 : Steel manufacturing stage

0.004 wt% or less of carbon (C), 0.2 to 0.8 wt% of manganese (Mn), 0.05 wt% or less of silicon (Si), 0.02 wt% or less of sulfur (S), 0.02 to 0.10 wt% of aluminum (Al), and nitrogen (N ) 0.002 to 0.006% by weight, molybdenum (Mo) 0.1 to 0.3% by weight, zirconium (Zr) 0.04 to 0.09% by weight, boron (B) 0.001 to 0.003% by weight, the balance of Fe and impurities, the zirconium (Zr Steel for tin-plated discs having an atomic ratio of) / carbon (C) in the range of 1.3 to 3.5 is produced.

S2 : Hot rolled and Winding step

The hot rolling and winding step is performed by hot rolling the steel produced in step S1), and then ii) hot rolling.

Iii) hot rolling

The hot rolling is preferably started at 1100 to 1150 ℃, A _r3 of 800 to 880 ℃ Finishing hot rolling at the transformation point desirable.

When the start temperature of hot rolling exceeds 1150 ° C, grains may coarsen as the passing time between hot rolls increases to secure the finish rolling temperature, thereby degrading product machinability. It is not preferable because there is a problem that it is difficult to secure the finish hot rolling temperature.

In addition, when the finishing temperature of hot rolling exceeds 880 ° C, there is a problem that the temperature difference with the transformation point is small and the residual ratio of the deformation zone is low, making it difficult to improve the recovery characteristics of the target cold rolled sheet. As the mixing of the merchant ferrite grains proceeds rapidly, not only the workability of the final product is lowered, but also the load of the hot rolling roll increases, which is a problem that causes a material variation, which is not preferable.

In addition, the steel can be further homogenized before the hot rolling step. At this time, the homogenization treatment is preferably carried out in the austenite single-phase zone which can coarsen the initial austenite structure as much as possible.

Ii) hot rolled up

In the hot rolled winding process, precipitation of carbide and aluminum nitride (AlN) occurs, and through the optimization thereof, desired materials and workability can be obtained. It is preferable to perform the said hot rolled winding at 500-650 degreeC. If the said coiling temperature is less than 500 degreeC, the precipitation behavior of the solid solution N in steel is inadequate, and it acts as a factor which reduces the aging of a product. In addition, when the coiling temperature exceeds 650 ℃, there is a problem that it is difficult to produce a tin-plated master plate of the target precursor quality to grow crystal grains of the hot-rolled sheet is undesirable.

S3 : Annealed step

Next, the wound binder is annealed. At this time, it is possible to produce a tin-plated master plate having a respective roughness according to the annealing temperature. Specifically, the annealing temperature is 510 to 545 ° C (T6 grade), 545 to 595 ° C (T5 grade), 595 to 655 ° C (T4 grade), 655 to 695 ° C (T3 grade), 695 to 735 ° C (T2 grade) , 735 to 760 ℃ (T1 grade) tin plated original can be produced respectively.

In addition, prior to the annealing step, it is possible to further carry out the step of cold rolling the resultant wound to a desired thickness by a conventional method.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are only preferred examples of the present invention, and the present invention is not limited to the following Examples.

< Example 1-2 and Comparative example 1-2: Steel Fabrication>

After continuously casting a steel containing the components of Table 1 and Fe in the amount of the remainder, the slab was reheated in the austenitic single-phase station to start hot rolling around 1100 to 1150 ° C, and finish hot rolling at 800 to 880 ° C. Was carried out.

After hot rolling, it cooled to 500-650 degreeC at the cooling rate of 20 degree-C / sec, and then wound up at the temperature maintained.

Table 1

division Chemical content (% by weight) Zr / C atomic ratio C Mn Si S Al N Mo Zr B Example 1 0.0024 0.32 0.008 0.006 0.036 0.0031 0.14 0.042 0.0018 2.308 Example 2 0.0031 0.24 0.021 0.012 0.045 0.0024 0.19 0.081 0.0021 3.446 Comparative Example 1 0.0028 0.26 0.015 0.011 0.039 0.0033 0.21 0.013 - 0.612 Comparative Example 2 0.0370 0.38 0.036 0.004 0.033 0.0114 - - 0.0015 0.000

< Measuring Quality >

Using the steels of Examples 1 and 2 and Comparative Examples 1 and 2, the roughness according to the annealing temperature at the time of continuous annealing was measured, and the measurement results of Example 1 and Comparative Example 1 are shown in FIG. . In addition, the results of measuring the quality of Example 2 and Comparative Example 2 are shown in Table 2 below.

TABLE 2

division Annealing Temperature (℃) Hardness (HR30T) Quality Machinability (O: Good Machinability, X: Bad Machining) Example 2 530 72.9 T6 O 540 71.4 T6 O 570 66.2 T5 O 620 61.7 T4 O 680 56.6 T3 O 710 52.8 T2 O 755 50.4 T1 O Comparative Example 2 520 73.0 T6 X 570 72.4 T6 X 620 61.7 T4 X 680 57.8 T3 X 710 56.9 T3 O 750 57.1 T3 O

2, in the steel of Example 1, the recovery region of the cold rolled sheet is enlarged during continuous annealing heat treatment, so that the heat treatment temperatures are respectively 510 to 545 ° C, 545 to 595 ° C, 595 to 655 ° C, 655 to 695 ° C, and 695. To 735 ° C, 735 to 760 ° C, the target precursor quality T6 (67-73 based on HR30T value), T5 (62-68 based on HR30T value), T4 (58-64 based on HR30T value), T3 (54 to 60 based on HR30T value), T2 (50 to 56 based on HR30T value), and T1 (46 to 52 based on HR30T value) were secured.

On the other hand, the steel of Comparative Example 1 using ultra-low carbon steel was able to secure the T1 grade quality through the continuous annealing process, but the heat treatment is performed when the atomic ratio of zirconium, boron, and zirconium / carbon is outside the scope of the present invention. As the recovery region of the material narrowed, recrystallization proceeded rapidly during continuous annealing, and it was confirmed that the target T2 grade to T6 grade quality could not be secured by changing the annealing temperature as in the present invention.

Therefore, in order to manufacture the tin-plated master plate of the precursor quality from the steel of Comparative Example 1, the annealing plate of the roughness T1 grade is manufactured by continuous annealing as in the existing method, and then the stepwise It should be manufactured by increasing the deformation resistance. However, in this case, there is a problem that the nonuniformity of the material increases due to the increase in the processing cost according to the secondary processing and the difference in material deformation resistance behavior according to the secondary reduction ratio during the manufacturing of the material.

In addition, referring to Table 2, the disc made of the steel of Comparative Example 2 using a medium-low carbon aluminum-killed steel was able to secure a T3 grade or more through continuous annealing, but carbon, nitrogen, molybdenum, zirconium As the composition is outside the scope of the present invention, it was confirmed that the quality of T1 to T2 grade can not be secured. In addition, after annealing, the steel of Comparative Example 2 caused work defects such as fluting due to stretch-strain or work bending in the machining step due to the solid solution element present in the steel. On the other hand, the original disc manufactured from the steel of Example 2 had a rolling quality, and was excellent in workability according to the annealing temperature.

Therefore, the steel having a specific composition of the present invention can be produced by the tin-plated master plate of the fineness T1 grade excellent in aging resistance and workability, the recovery region of the material is expanded, so that the fineness T2 to It can be produced with a tin-plated disc of excellent workability of T6 grade.

As mentioned above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. This is possible.

1 is a view showing a manufacturing process of the tin-plated disc according to an embodiment of the present invention.

2 is a view showing the quality of the steel according to the annealing temperature according to Example 1 and Comparative Example 1 of the present invention.

Claims

0.004 wt% or less of carbon (C), 0.2 to 0.8 wt% of manganese (Mn), 0.05 wt% or less of silicon (Si), 0.02 wt% or less of sulfur (S), 0.02 to 0.10 wt% of aluminum (Al), and nitrogen (N ) 0.002 to 0.006% by weight, molybdenum (Mo) 0.1 to 0.3% by weight, zirconium (Zr) 0.04 to 0.09% by weight, boron (B) 0.001 to 0.003% by weight, the balance of Fe and impurities, the zirconium (Zr Tin-plated disc, the atomic ratio of () / carbon (C) is present in the range of 1.3 to 3.5.

0.004 wt% or less of carbon (C), 0.2 to 0.8 wt% of manganese (Mn), 0.05 wt% or less of silicon (Si), 0.02 wt% or less of sulfur (S), 0.02 to 0.10 wt% of aluminum (Al), and nitrogen (N ) 0.002 to 0.006% by weight, molybdenum (Mo) 0.1 to 0.3% by weight, zirconium (Zr) 0.04 to 0.09% by weight, boron (B) 0.001 to 0.003% by weight, the balance of Fe and impurities, the zirconium (Zr Preparing a steel for tin plated disc, wherein the atomic ratio of c) / carbon (C) is in the range of 1.3 to 3.5;

Hot rolling and winding the steel; And

Annealing the winding result

Method for producing a tin-plated disc comprising a.

The method of claim 2,

In the annealing step, the annealing temperature is 510 to 545 ℃ (T6 grade), 545 to 595 ℃ (T5 grade), 595 to 655 ℃ (T4 grade), 655 to 695 ℃ (T3 grade), 695 to 735 ℃ (T2 Grade) and the manufacturing method of the tin-plated master disc of 735-760 degreeC (T1 grade).