JPS5976823A - Manufacture of hot rolled steel sheet - Google Patents

Abstract

PURPOSE:To manufacture the titled steel sheet camparable to a cold rolled steel sheet with respect to surface properties and quality by hot rolling a steel material contg. extremely reduced amounts of C and P and having a restricted Mn content, heat treating the hot rolled steel sheet under specified conditions, and subjecting it to skin pass rolling after cooling and pickling. CONSTITUTION:A steel material contg. <=0.02% C, <=0.30% Mn and <=0.010% P is hot rolled, coiled, and held at >=600 deg.C for >=3hr. The hot rolled steel sheet is cooled to room temp., pickled, and subjected to skin pass rolling at 1-5% draft.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a copper plate that achieves surface texture and ablation characteristics equivalent to those of a cold rolling process only by hot rolling.

As is well known, the cold rolling process is widely used in automobiles, home appliances, copper furniture, food cans, containers, etc. !
Since cold-rolled steel products are manufactured by receiving raw materials from the hot rolling process, they have excellent surface properties and material properties, but they are cheap. Meanwhile, research and development in the steel industry is progressing, elucidating the causes of fires in steel materials and establishing methods to improve material properties.
Improvements in industrial engineering have been remarkable, and in recent years, it has become possible to produce significantly superior preparations. It has become possible to continuously produce high-quality steel products by controlling the temperature or cooling rate during transportation between processes.

The present invention was developed by the inventor in the technical background
A conclusion to the experimental prototype study! 4! According to the present invention, it is possible to manufacture steel products that have the same surface properties and Toga properties as cold-rolled steel sheets by only hot rolling, without using a cold rolling process. The characteristics of Komono are C50.02%, MnS
2.30%, P≦0.010% tin is hot rolled,
1 piece of rolled paper is treated at 00℃ or higher for 3 hours or more, cooled to room temperature after gummy, washed, and skin with 1% or more of 5 pieces or less.
The present invention provides a method for producing a thin hot-rolled tX sheet having surface properties and texture characteristics comparable to that of a cold-rolled sheet, which is characterized by subjecting it to hot-rolling.

The reasons for each limit π in the present invention will be explained below.

C is a component that affects the strength and workability of hot-rolled steel sheets.C exceeds 0.02%, as shown in Figure 1 (a) ←), which leads to a decrease in elongation due to poor quality of the material. Preferably C
It is 0.01% or less.

Mn is a component that affects strength and workability, so if the upper limit of Mn is limited to 0.30%, if the Mn content exceeds 0.3%, the workability of the material will deteriorate. Not.

P is a component that affects strength and workability, and Pchi is 0.0.
If it exceeds 10%, deterioration in negative hardening workability is observed as shown in FIG. 2, which is not acceptable. The accuracy is less than 0.005%.

As shown in FIGS. 3 and 4, a temperature of 600 C or more is required for maintaining the abrasiveness of the product during winding or knitting. As shown in Figure 4, after winding around the coil, cover the entire coil with a heat insulating cover or a heat insulating cover (with heating device), etc.
It is desirable to increase the ductility of the hot coil by keeping it warm, and the temperature at which the young fruit can be grown is 600°C or higher. In the figure, #8 shows I4 which is dispersed across bh after heating and/or heat retention according to the present invention. Regarding the heat retention time, the effect will be stabilized if the entire coil is kept warm or heated at 600u or more for 3 hours or more. The conditions for keeping the temperature at 600℃ or higher for 3 hours or more are as follows: A coil wound with a coil length of 670U or higher must be kept at a temperature of 3:01 tJ.
It also includes air cooling to 600°C on tL.

Also, as shown in Fig. 3 above, the higher the coiling temperature, the better the ductility, but if the plate thickness is thin, cooling on the hot run table will be faster, but it will be difficult to maintain the coiling temperature at that temperature. .

In this case, the winding shift degree (550
It is wound up at ~600°C), then charged into a heat retention furnace or annealing furnace, and heated to 600°C μl soil x 3 hours at a temperature higher than HI and/or kept at a temperature of 1T to prevent low ductility. This is because no improvement in ductility is observed when fd is 600'C or less, with the lower limit being 600°C. The holding time was set to 3:1ii1 or more because it was within 3 hours and no young fruit with improved ductility was observed.

The reason why the lower limit of skin pass rolling was set at 1% is that if it is 1-inch, as shown in Section 5-1 (a), the board surface will not be as beautiful as the surface after pickling, and if it exceeds 1%, commercially available This is because a surface texture comparable to that of cold-rolled steel sheets can be obtained.

The upper limit was set at 5% because when rolling between ends of more than 5 inches, the strength does not increase significantly and the p elongation decreases as shown in Figure 5 (b), resulting in poor workability. . For the above reasons, the skin pass rolling was performed at a rate of 1% or more and 5% or less.

Furthermore, in the present invention, it is preferable that the cross-sectional shape of the rough Δ- is formed under the following conditions.

To obtain uniform grain size with hot IHJ compaction M: R rolling k A
It is necessary to terminate the process at a temperature higher than the rs point. However, for ultra-low carbon steels (cans with low CrMn), the Ar3 transformation point is low, so the heating temperature of the slag must be adjusted to ensure the final rolling end temperature. Generally employed methods include increasing the thickness of the rough bar or reducing the amount of roll cooling water during rolling. Both methods are not preferred from the viewpoint of cost and quality, as they result in deterioration of energy consumption and the environment in which the rolling rolls are used.

In normal rolling, the cooling rate of both etched parts in the width direction of a copper strip is faster than that of the center part in the width direction, and the temperature difference between the center part in the width direction and the most etched part is generally 40 to 60 degrees Celsius (the edge part is faster). low). Therefore, in order to obtain uniform grain size across the width direction, it is necessary to secure Ar at the edgemost part, and then the center part will have Ar 5 points + 40 ~
The temperature reaches 60 degrees Celsius, which has a great effect on the production, energy consumption, heat cracking of the rolls, etc. The inventors of the present invention conducted tests with various cross-sectional shapes of slabs, and found that when a rough bar with a cross-sectional shape that satisfies the defect conditions is used, grain size distribution can be obtained over the entire surface in the width direction of the slab.

By applying this knowledge to the present invention, it is possible to significantly improve the practicality of the method for producing a product equivalent to cold-rolled copper plate, in which the material quality is uniform throughout the copper strip l'' direction by hot rolling. I can do it.

・e≧100 ate-te≧(10-C@g) Showing the same side. Note that the porcelain materials that can be used in the method of the present invention are rimmed steel,
Either semi-killed steel or killed steel can be used, and it may be manufactured by either the ingot making method or the continuous bell making method. Therefore, A/- is not an essential component, but is used depending on the purpose.

Next, Examples of the present invention are shown in Table 1 together with Comparative Examples.

It is clear from the table that the present invention examples A2, 5, 6, 9~
13.16.17 all have surface roughness MRa? o is in the range of 41 to 0.57, which is equivalent to v'A copper plate, and the mechanical properties are T and S of 26 to 32.5 Y and P of 18 to 24 Et
is in the range of 48-57. In contrast to this, comparative example AI
=3.4, 7, 8, 14, 15, 18, and 19 did not exhibit surface properties or Toga characteristics that satisfied the objective of the present invention as described in the evaluation summary.

As explained above, the present invention involves hot-rolling a copper material with controlled C, Mn, and P values at a temperature of 670°C or higher and rolling it at least 6
00℃ for 3 hours, or coiled steel at 600℃ or higher and kept it warm for at least 3 hours, or coiled steel at less than 600℃ and kept it warm for 3 hours or more at 600℃ or higher, then cooled and pickled. Since skin pass rolling is performed at a rolling reduction of 1% or more and 5 inches or less, the resulting steel exhibits surface properties and anti-corrosion properties equivalent to cold-rolled steel sheets, and can be used in applications that were previously limited to cold-rolled steel sheets. EJ performance, which has great effects on the industrial field, such as reducing manufacturing costs and providing inexpensive and superior copper materials.

[Brief explanation of drawings]

1st Mm l't' element 1 mechanical properties. relationship. A (6)
Figure 2 shows the relationship between the amount of phosphorus in steel and Et, one of the mechanical properties. Figure 3 shows the hot coiling temperature and mechanical properties of steel. One of the relationships between Et and water content - Figure 4 - Heat retention temperature and heat retention time for woven honeycomb
The former is shown in (a) and the latter is shown in (b) in a diagram showing the relationship with Et, one of the JK special properties. This is the first blessing of par (preparation). 1: Rough par agent Taniyama HariAM-”2 (...-zu7111 figure (a) C (%) (b) P (%) Figure Nukin Pass Reduction # (Phantom Skin Pass Reduction Rate (U6)

Claims (1)

[Claims] 1. C50.02%, MnS2.30%, P≦0.
010 inch copper material is hot-rolled, treated at 600°C or higher for 3 hours or more after winding, cooled to a chamber temperature, pickled, and then subjected to skin pass rolling of 5% or more and 1% or more. A method for producing a thin hot-rolled steel sheet having surface texture and material properties comparable to those of a cold-rolled steel sheet. 2, C50.02%, MnS2.3 (1, P≦0.
After hot rolling, a steel material of 0.010 mm is rolled up at a temperature of 600°C or higher, kept at a temperature of 600°C or higher for 3 hours or more, cooled to room temperature, pickled, and then subjected to skin pass rolling of 1% or less of 5% or more. Surface texture comparable to that of cold-rolled steel sheets, characterized by rough edges,
A method for manufacturing a thin hot-rolled steel sheet according to claim 1, which has material properties. 3. C50.02%, MnS2.30%, P≦0.
OJ, 0-chi steel material is rolled up at 670℃ or higher after hot rolling,
After cooling at a cooling rate of 0.38°C/m11 or less, it is pickled and subjected to a skin pass of 5% or less and 1% or more, and has surface texture and material properties comparable to cold M1 pressure-treated steel sheets.
! A method for manufacturing a thin hot rolled steel sheet according to claim 1. 4, C50.02%, MnS2.30%, P≦0.
0.010% steel material is completed and coiled at less than 600°C, heated and maintained at 600°C or more for 3 hours or more, then cooled to room temperature, and after grid washing, 5% or less 1 The method for producing a thin hot-rolled steel sheet according to claim 1, which has surface texture and material properties comparable to those of cold-rolling when subjected to skin pass rolling of 7% or more. 5. The shape of the rough par to ensure the finishing temperature of the etched part in the width direction during hot rolling of steel material: ・02100w+m *ts-4c≧(10Cog)X2+20 However, Ceg
-C+ 1/6 Mn (see Figure 6) %#'F KM range 1
A method for manufacturing a thin thermally rolled steel sheet according to Items 2, 2, and 3 of MJj.