JPS59173222A - Manufacture of soft surface treating stock sheet - Google Patents

Abstract

PURPOSE:To manufacture soft surface treating sheet efficient in workability, by continuously annealing the cold steel sheet of low carbon aluminum killed steel having fixed amounts of N and P at a specific temperature. CONSTITUTION:The slab of low carbon aluminum killed steel having the composition of under 0.05% S under 0.40% Mn, 0.010-0.08% Al, under 0.0020% N, under 0.010% P, under 0.0040% O and not more than 0.018% P+5N is hot-rolled to sheet material. Then, it is cold-rolled by a draft of 80% min and further treated with recrystallization annealing for a short time of 5 sec to 3min at a temperature of recrystallization temperature -850 deg.C by continuous annealing method. The soft surface treating steel sheet having efficient workability, especially to T-1 in temper degree, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a soft surface treatment original plate having excellent rolling performance and excellent workability by continuous annealing, particularly a temper group T-1 soft surface treatment original plate.

Tin-plated steel plate is a tin-plated steel plate, or tin-free steel (hereinafter referred to as T.F.
Surface-treated steel sheets such as S are used for food cans, aerosol cans,
Often used in easy-open cans.

These surface-treated copper plates have strength depending on their use.

The degree of temper (temperature and degree of temper) is specified as a guideline for selecting appropriate ductility and other properties.9 This temper group is expressed in terms of surface hardness (HR30T), ranging from soft to T-1 ( HR30T: 46-52
), T-2 (HR30T: 50-56), T3 (HR
30T: 54-60), T-4 (Hn30T: 58-6
4), T-5 (HR30T:62-68), T6(
HR30T: 67 to 73), DR-8, DR-9 and DR-10, but continuous annealing with rapid heating and short-time heating does not yield a soft original sheet when all continuously cast materials are used. Conventionally, T-1 soft surface-treated original sheets were manufactured by box annealing. However, compared to continuous annealing, box annealing has disadvantages such as inferior shape, nonuniform mechanical properties in the longitudinal direction of the coil, and inferior productivity, and moreover, manufacturing costs are high.

These tinplates, T, F, and S, have a plate thickness of 0.2 to 0.30
Ultra-thin materials on the order of mm are the mainstream, and in this case, cold rolling inevitably involves high reduction rate cold rolling. Therefore, the rolling load during cold rolling increases, and moreover, the occurrence of plate breakage during cold rolling increases, which is a cause of inhibiting the productivity of cold rolling.

Furthermore, in recent years, tinplate, T, F, and S have been subjected to severe processing, such as multi-stage drawing or deep drawing followed by ironing, which has improved not only corrosion resistance but also
It is a must-have product that also has excellent workability.

The present inventors conducted various studies in order to overcome the above-mentioned drawbacks of the conventional method. As a result, we found that there is no fear of plate breakage during cold rolling, it is possible to reduce the weight consumption during cold rolling, and it is possible to achieve excellent workability due to continuous annealing. Soft surface treated steel sheet, especially once tempered T-
1 manufacturing method has been completed.

The gist of the present invention is that C:00 as weight 31%
5% or less, Mn: 0.40% or less, At: 0.
010~0, 080%, N: 0.0020 or less, P:
0.010 or less.

A low carbon aluminum killed steel consisting of p + 5 - N < 0.018%, O: 00040% or less, balance iron 2 and non-N4 kaI is hot rolled, and then the rolling reduction is 80%.
After performing the above cold rolling, a short time recrystallization annealing is performed for 5 seconds to 3 minutes in a temperature range of recrystallization temperature to 850°C by continuous annealing method. It is in the manufacturing method of the original plate for soft surface treatment.

The present invention will be explained in detail below.

First, the components that make up the entire present invention will be explained.

Since C hardens nine surfaces, its upper limit is set at 0.050%. Since the characteristics of the present invention are realized by significantly reducing the amount of C, the lower limit value is lower than 000, which is possible with current steel manufacturing technology.
It includes up to about 1%, but in order to reduce C to 0.01% or less] (special treatment such as nitrogen degassing treatment is required, which is costly and causes external noise, so from an industrial point of view 0.01%). 015
% or more is preferable.

Mn must be contained in an amount of 0.05% or more to prevent hot embrittlement caused by S, which is an unavoidable impurity.
If it exceeds %, the steel becomes hard like C, and the characteristics of the present invention are lost. The preferred range is 0.1 to 0.3 h.

At least 0 is used as a deoxidizing agent to reduce oxide inclusions that are harmful to workability, and to suppress hardening due to strain aging during surface treatment by tracing N fixation in the steel. It is necessary to contain .010%. However, if it exceeds 0.08%, the steel becomes hard and surface flaws increase. The preferred range is 0.0015% to 0.05%.

N and P are the most important constituent elements of the present invention.

By lowering both P and N, a remarkable softening effect and a remarkable improvement in cold rolling ability were obtained, which were greater than previously thought. In other words, it has good workability even when cold-rolled at a high rolling rate like a tinplate original plate, has less plate breakage, and requires less electricity for cold-rolling, and in addition, continuous annealing has a soft surface of T-1 once tempered. It is possible to manufacture treated original plates.

Figures 1 to 3 are C: 0.02 to 0.04% + Mn
:010~030%, At:0015~0040 steel, relationship between N content and hardness of tin plate (first
Figure 9: Relationship between P amount, N time, and plate fracture during cold rolling (Figure 2).

Relationship between flange formability after drilling and I processing (Fig. 3)
shows. Figure 1.2 shows the average height of a large number of experiments.

The manufacturing conditions shown in FIGS. 1 and 2 are as follows.

Sushig heating wetness: 105υ~1255℃ Hot rolling finishing temperature: 870~890℃ Winding temperature: 550~650℃ Cold rolling rate: 87~90% Annealing conditions Near 00℃ x 30 seconds + 400℃ x 60 seconds Skin pass: 15% Plating: Reflow treatment after electrolytic tin plating The numbers in FIG. 1 are Rockwell surface (HR30T). As can be seen from Figure 1, the amount of P is 0.010%.

It can be seen that a soft T-1 tin plate can only be produced by setting N<2Q ppm and P+5N<0.018%.

The fracture characteristics of the plate shown in Figure 2 were determined using a laboratory cold rolling machine.
mm (cold rolling ratio: 90%) and evaluated by the number of sheets that broke (test number: 20). The numbers in the figure are the number of broken plates. Therefore, the larger the number, the worse the cold rolling performance. P: 0.010 or less, N: 0.0020
% or less and P+5·N≦0018, plate breakage during cold rolling is small, and it can be seen that cold rolling performance is excellent within the scope of the present invention.

Figure 3 shows the flange formability after P acid removal and I processing.

The flange workability beam shown in Fig. 3 was expanded from the top with a conical punch after 1710 hours, and the maximum expansion rate at the time of cracking was shown. Condition A is a case where the same material sound as in FIGS. 1 and 2 is used, and the tempering degree is changed depending on the amount of P.

Condition B was obtained by changing the annealing conditions including box annealing, and achieved T-1'! ! −
It is the one at the time of manufacture. It can be seen that both have excellent Franz formability with Po of 0.010% or less.

The lower limits of the amounts of P and N are the hardness and cold rolling performance listed above.

It was specified from the viewpoint of workability. Furthermore, P≦0008%.

By setting N to 0.0017% and P+5 to N60016%, the effect of the present invention is 80. be revealed.

Since S causes inclusions in the steel, surface defects in the surface-treated steel sheet, and cracking during processing, it is preferable that the S content is 0.015 mm or less.

It has a significant effect on 0 beam, I processability and flange formability after DI processing, and when it exceeds 40 ppm f, these properties are significantly deteriorated. The preferred range is 30ppm
The following fraudulently invented steel slabs are melted in a normal melting furnace such as a converter, vacuum degassed as necessary, ingot-formed and bloomed, or continuously cast. .

The characteristics of the present invention are not impaired by the heating temperature of the thermosump. Therefore, it is not affected by direct rolling of continuously cast slabs or blooming-rolled slabs, nor by the temperature of the steel slabs charged into the heating furnace.

The hot rolling finishing temperature needs to be 830°C or higher.

If the finishing temperature is lower than 830°C, the shape of the copper strip will be poor, it will be difficult to perform stable operation, and the in-plane anisotropy of the finished product will increase.

It is known that the winding temperature history affects the material properties of continuous annealing. When cold-rolled steel sheets for deep drawing are produced by continuous annealing, carbides become lumpy due to high-temperature winding, and the workability of the finished product (r
However, thin plates such as tinplate T, F, and S are more likely to crack during processing. Therefore, it is preferable to set the winding temperature to 680° C. or lower in view of the shape distribution of carbides in the hot-rolled sheet. Further, if the winding temperature is lowered too much, the steel sheet becomes hard.

A preferred winding temperature range is 560 to 680°C.

It is then subjected to descaling treatment and subjected to cold rolling. Cold rolling rate is normal surface treated steel sheet (tinplate).

T, F, S) Do 80 or more steps in the same way.

Annealing is performed by continuous annealing instead of conventional box annealing. The annealing cycle is for 5 seconds to 3 seconds in the temperature range of recrystallization temperature to 850°C.
A short recrystallization annealing is performed for 1 minute.

The preferred annealing temperature range is 680-750'C.

If necessary, an overaging treatment of 250 to 450° C. for 30 seconds to 5 minutes is performed, but by performing the overaging treatment, a temperature of T-1 can be stably obtained. It is then skin-pass rolled and subjected to surface treatment.

According to the method of the present invention, T-1 grade can be easily produced by continuous annealing. Therefore, a method has been proposed (Japanese Patent Publication No. 1982-4116) in which the skin pass rate is changed after annealing to adjust the tempering level of the surface-treated original sheet. However, if combined with the present invention, the steel composition and hot rolling will be reduced.

By changing the skin pass rate while keeping the annealing conditions constant, p
, all grades of surface treated original plates (tinplate).

It is also possible to manufacture T, F, S).

Examples Steels shown in Table 1 were melted in a converter, ingot-formed, and bloomed.
Alternatively, a continuously cast steel billet was hot rolled to 27 mm under the conditions listed in Table 1, pickled, and then cold rolled to 0.32 mm. Subsequently, annealing was performed under the annealing conditions listed in Table 1 to obtain a 1.0
% skin pass and electrolytic tin plating or chromic acid treatment.

Similarly, Table 1 shows the mechanical properties after surface treatment.

It can be seen that soft tinplates of T-1, soft T, F, and S can be manufactured within the scope of the present invention. - Coils A I 1 to 1 manufactured by a method outside the scope of the invention of strength wood
It can be seen that No. 4 does not satisfy the T-1 standard.

Note that the power consumption during cold rolling of steel within the scope of the present invention was 83 to 87 times that of steel outside the present invention.

[Brief explanation of drawings]

Figure 1 shows P month, N amount and hardness of tin plate (HR30T)
FIG. 2 is a diagram showing the relationship between 1dPi and Ni and plate breakage during cold rolling. FIG. 3 is a diagram showing the relationship between PR glue and tube expansion rate after I processing. 1 8'1 N, spm) 1 square 2 closed

Claims (1)

[Claims] C: 0.05% or less, Mn: 0.4 as weight%
0% or less, A/: 0.010-008%, N: 0
．． 0020% or less, P: 0.010% or less and P+5・
N≦0.018%, o: 0.0040 inches or less, the balance consists of iron and unavoidable impurities. Low carbon aluminum killed @ was hot rolled and then cold rolled with a rolling reduction of 80% or more. After that, the recrystallization temperature is ~85% by continuous annealing method.
A method for manufacturing a base plate for soft surface treatment of Tentsuya Ichigo T-1, which is characterized by performing short-time recrystallization annealing for 5 seconds to 3 minutes in a temperature range of 0°C.