JP3394598B2 - Packing band and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packing band and a manufacturing method thereof.

[0002]

2. Description of the Related Art A packing band used for packing
As a steel packing band with excellent elongation and tensile strength
Are known. This packing band generally has the following
Manufactured by various methods. C: 0.05 to 0.50 wt%,
Mn: 0.5-1.0 wt%, balance Fe and unavoidable impurities
A steel material made of pure material is hot-rolled to a specified thickness (usually
Cold rolling is performed so that the thickness becomes 0.3 to 1.6 mm. So
After that, perform the following three types of annealing (1) to (3)
Target material (Tensile strength (TS) ≧ 80kgf
/ Cm ² , 7 ≦ elongation (EL) ≦ 16%) at the same time
Add temper color and remove rolling distortion. (1) Brewing treatment In this process, cold rolled coils of the above composition are
Method, etc., to 300-500 ℃, then air-cooled
Be done. As a result, the mechanical characteristics are improved and the coil shape is improved.
The shape is corrected and a temper color is added. (2) Austempering In this treatment, the cold rolled coil of the above composition is₃ 
Heated up to the transformation point or higher and turned into an austenite structure
Later, A₁ Quenched in a constant temperature bath below the transformation point (lead bath, etc.)
Is maintained at that temperature for a certain period of time or more, causing an isothermal transformation.
It As a result, a transformed structure composed mainly of bainite was formed.
Appropriate mechanical properties are obtained and rolling strain is removed. (3) Batch annealing treatment This process has the same effect as the bluing process of (1).
In this case, the temperature is 300 to 500 ° C due to batch annealing.
After being heated in the range for 3 to 10 hours, it is air-cooled. to this
Improved mechanical properties and modified coil shape
It

[0003]

However, the above-mentioned conventional manufacturing method of the packing band has the following problems. (1) A large amount of equipment cost is required because a processing line specific to the packing band such as a bluing processing line or an austempering processing line is installed for heat treatment to manufacture a packing band with excellent elongation and tensile strength. In addition, labor costs for operating and maintaining these facilities will be added, and the cost will increase. (2) In batch annealing, the processing capacity is lower than that of a continuous annealing line for ordinary low carbon (extremely low carbon) steel, and the fuel cost is higher than that of a continuous annealing line.

For the above reasons, existing low carbon (extremely low carbon)
Heat treatment of the packing band using the continuous annealing line
In other words, from the aspect of equipment cost, fuel cost, labor cost, and logistics
A big merit is obtained. However, the above C:
0.05 to 0.50 wt%, Mn: 0.5 to 1.0 wt
%, The balance Fe and unavoidable impurities,
Annealing temperature of steel materials (650-
When annealed at 950 ° C), there is no problem with the elongation value, but the yield
Point (YP) and tensile strength (TS) are target values (both are 8
0 kgf / mm ² Above) is not reached. Mechanical properties
The yield point and tensile strength depend on the annealing temperature as the recrystallization temperature of the material.
When it exceeds the limit, it begins to decrease sharply and the yield ratio also decreases.
In addition, growth will improve. Where the recrystallization temperature is reached
Since the rolling structure remains before, high yield point, high
Both tensile strength is obtained, and when using an automatic binding device,
The wrapping band does not bend when passing through the guide. Especially
Between 100 ° C below the crystallization temperature and the recrystallization temperature
When annealed, it has an excellent yield point and tensile strength, and at least 7%
Is obtained, which is a desirable property as a packing band.
It However, in the C and Mn-added steels having the above-mentioned composition,
Since the crystallization start temperature is as low as around 600 ℃, existing continuous annealing
Temperature that exceeds recrystallization temperature when continuous annealing is performed using equipment
Therefore, it is annealed and the mechanical properties cannot be secured.

In view of the above circumstances, it is an object of the present invention to provide a packing band capable of ensuring the required mechanical characteristics even if it is continuously annealed by using an existing continuous annealing equipment, and a method of manufacturing the same.

[0006]

Means for Solving the Problems The present inventor has conducted various experiments and researches in order to achieve the above object, and as a result, C,
The inventors have found that the existing continuous annealing equipment can be used by increasing the recrystallization temperature by adding Ti to the Mn-added steel, and completed the present invention. Specifically, the packing band of the present invention and the method for manufacturing the same are C: 0.05 to 0.50w.
t%, Mn: 0.5 to 2.0 wt%, Ti: 0.050
Steel material consisting of wt% or more, the balance being Fe, and unavoidable impurities is hot-rolled at a coiling temperature in the range of 400 to 600 ° C., cold-rolled at a rolling reduction of 40% or more, and 600 to 7
It is characterized in that annealing is performed at a temperature within the range of 00 ° C.

Here, it is preferable to set the hydrogen concentration of the atmosphere gas to 2% or less when performing the annealing. Further, the packing band of the present invention has C: 0.05 to 0.50 wt.
%, Mn: 0.5 to 2.0 wt%, Ti: 0.050 w
A steel material containing t% or more, the balance being Fe, and unavoidable impurities is hot-rolled at a winding temperature in the range of 400 to 600 ° C., cold-rolled at a rolling reduction of 40% or more, and 600 to
Annealed at a temperature in the range of 700 ℃, 80kgf / mm
It is characterized by having a yield point and tensile strength of ² or more, an elongation in the range of 7% to 16%, and a yield ratio of 90% or more.

[0008]

[Function] By continuous annealing in the range of 600 to 700 ° C, the yield point and tensile strength of 80 kgf / mm ² or more, 7%
In order to obtain a material having an elongation within a range of up to 16% and a yield ratio of 90% or more, the composition of the material is limited as follows. C: C is an element necessary to secure the tensile strength of the material, and 0.05 wt% is necessary at a minimum. However, excessive addition leads to a problem that the tensile strength increases more than necessary and the notch cannot be made during actual binding. Further, since C has the effect of lowering the recrystallization temperature, its upper limit is 0.50.
It was set to wt%.

Mn: Mn, like C, is effective in increasing the tensile strength but lowers the recrystallization temperature. Further, excessive addition leads to cost increase. Therefore, the concentration is set to 0.5 to 2.0 wt%. Ti: Ti has the effect of increasing the recrystallization temperature. The recrystallization start temperature is 700 ° C. in the above C and Mn component ranges.
Before and after, the concentration needs to be 0.050 wt% or more to enable continuous annealing treatment. The upper limit is 0.150 wt%. The reason is that excessive addition leads to an increase in yield point and tensile strength more than necessary and leads to an increase in cost.

Winding temperature: When the winding temperature exceeds 600 ° C., the crystal grains of the mother plate become coarse, and it becomes impossible to secure a yield point and a tensile strength of 80 kgf / mm ² or more. In addition, the pickling speed for descaling becomes slower, leading to lower work efficiency. If the temperature is less than 400 ° C, hardening due to work strain during rolling is not relaxed, the load in cold rolling increases, and at the same time, the shape of the steel sheet becomes significantly poor. For this reason,
The range was 400-600 degreeC.

Cold rolling reduction: The minimum value is 40 in order to refine the crystal grains of the unannealed plate and secure the target tensile strength.
%. High-strength steel such as this steel sheet has a large working resistance during rolling, and the deflection of the roll also becomes large, and if the reduction ratio is unnecessarily increased, the shape of the steel sheet becomes defective. Therefore, the upper limit of the rolling reduction is set to 70%. Annealing temperature: The recrystallization start temperature is about 700 ° C. depending on the above component system and manufacturing conditions. If it is annealed at a temperature higher than 700 ° C., a yield point of 80 kgf / mm ² or more and a tensile strength cannot be ensured, and the yield ratio is lowered, so that it is not suitable as a packing band. When annealed at a temperature below 600 ° C,
Softening due to recrystallization of the structure does not occur, and it becomes a material of higher strength than necessary. For this reason, by performing the annealing in the temperature range of 600 ° C. or more and 700 ° C. or less, the mechanical properties are secured and the continuous treatment with other low carbon materials (extreme low carbon materials) in the continuous annealing becomes possible.

Here, when performing annealing, if the hydrogen concentration of the atmosphere gas exceeds 2%, the oxide scale on the surface of the steel sheet is not sufficiently generated, and therefore the rust resistance during actual use is insufficient, so 2%. I did the following.

[0013]

EXAMPLES Examples of the present invention will be described together with comparative examples with reference to FIG. 1 and Table 1. The test material A in Table 1 shows the composition of the example, and the test materials B, C, and D show the compositions of the comparative example, and the balance of each test material is Fe and inevitable impurities. FIG. 1 shows Table 1.
3 is a graph showing the relationship between the annealing temperature and mechanical properties of each of the test materials A, B, C, D shown in FIG.

[0014]

[Table 1]

Each of the test materials A to D should have the components shown in Table 1.
After melting in a vacuum melting furnace, hot rolling at a finishing temperature of 850 ° C
Perform the process corresponding to the coiling temperature of 540 ℃,
Finishing a 0.9 mm sample with a bottom ratio of 50% 600-750
It was annealed at ℃. Specimen A has an annealing temperature of 7
When the temperature exceeds 00 ° C, recrystallization starts and the yield point and tensile strength decrease.
Slightly low but stable at yield point and tensile strength below 700 ° C
80 kgf / mm ² The above is obtained. Meanwhile, growth
Is used as a band material, because 7% is obtained at an annealing temperature of 600 ° C or higher.
Became a proper material. Specimen B is a component system of Specimen A
Although Ti was removed from the sample, it yielded more than Sample A.
Point, tensile strength is 10kgf / mm² More than that and recrystallized
The starting temperature has also dropped. Specimen C has a low concentration of C and Mn
Therefore, 80kgf / mm² Above yield point and tensile strength
I can't get it. On the other hand, the test material D has a high concentration of C and Mn.
Therefore, even at an annealing temperature of 700 ° C, 100 kgf / mm² Over
Although it has a high tensile strength, it has a high strength,
It is thought that inconvenience will occur when pushing. Well
Also, since the elongation is around 5%, it is suitable for impact load after bundling.
There is a problem with safety.

[0016]

As described above, in the packing band of the present invention and the method for manufacturing the same, since Ti is added in an amount of 0.050 wt% or more to the steel material in order to raise the recrystallization start temperature, the recrystallization start temperature is about 700 ° C. to become, as a result, conventional brewing process, can use low-carbon continuous annealing line for (ultra low carbon) Motoko existing without passing through the line, such as for austempering, 80 kgf / mm ² or more It is possible to obtain a yield point and tensile strength, a yield ratio of 90% or more, and an elongation within the range of 7% to 16%. Further, by using the above continuous annealing line and annealing at a temperature of 700 ° C. or lower, target mechanical properties can be obtained, at the same time rolling strain can be removed and a predetermined temper color can be added.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the annealing temperature and mechanical properties of each of the test materials A, B, C and D shown in Table 1.

[Explanation of symbols]

A curve B, C, D showing the relationship between the annealing temperature and the mechanical properties of the sample material of the example. Curves showing the relationship between the annealing temperature and the mechanical property of the sample material of the comparative example.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-300617 (JP, A) JP-A-58-25434 (JP, A) JP-A-57-185928 (JP, A) JP-A-61- 113723 (JP, A) JP 60-224718 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C21D 9/46-9/48 C21D 8/00-8/04 C22C 38/00-38/60

Claims (3)

(57) [Claims] 1. C: 0.05 to 0.50 wt%, Mn:
0.5-2.0 wt%, Ti: 0.050 wt% or more,
A steel material whose balance is Fe and unavoidable impurities is
Hot rolling at a winding temperature in the range of 0 to 600 ° C., 40
A method of manufacturing a packing band, which comprises cold rolling at a rolling reduction of not less than%, and annealing at a temperature within a range of 600 to 700 ° C. 2. The annealing is carried out at a hydrogen concentration of atmospheric gas of 2
% Or less, and the manufacturing method of the packing band according to claim 1. 3. C: 0.05 to 0.50 wt%, Mn:
0.5-2.0 wt%, Ti: 0.050 wt% or more,
The balance is 40% steel with Fe and unavoidable impurities.
Hot rolled at a coiling temperature in the range of 0-600 ° C, 4
Cold rolled at a rolling reduction of 0% or more, annealed at a temperature in the range of 600 to 700 ° C., yield point and tensile strength of 80 kgf / mm ² or more, elongation in the range of 7% to 16%, 90
A band for packaging, which has a yield ratio of at least%.