JPS58154403A - Method for heat insulation in direct feed rolling of steel material - Google Patents

Abstract

PURPOSE:To obtain a uniform strip edge temp. in direct feed rolling which rolls a continuous casting ingot to a strip without heating the same by maintaining beforehand the side surface parts in the longitudinal direction of a slab corresponding to the coldest point temp. part of the strip beforehand at the temp. higher than the temps. in the other parts from the stage of the slab. CONSTITUTION:In direct feed rolling wherein a continuously cast ingot is rolled to a strip without heating, heat insulating materials 8 are adhered over the entire width on the side surfaces of a slab 11 in the positions corresponding to the coldest points at the preceding and succeeding ends of the strip in the longitudinal direction thereof, that is, over the length 0.2L from the position where the length 0.1L is subtracted from the preceding end of the slab when the overall length of the slab 11 is defined as L and over the length 0.2L from the succeeding end of the slub 1. The slab is thereafter supplied to hot rolling mills. The materials 8 are moved horizontally by the operations of the arms 9 carrying said heat insulating materials at their forward ends and cylinders 10, whereby the heat insulating materials are adhered on the side surfaces of the slab 11.

Description

[Detailed Description of the Invention] In recent years, even in steel mills that consume a large amount of thermal energy for the purpose of saving labor and energy, various methods for saving labor and energy have been introduced.
1.The idea of direct rolling, which is carried out without heating, also saves time and effort. This direct rolling method requires a longer processing time after heating than the conventional method that uses a combination of a rolling heating furnace and a rolling mill. becomes a problem, and the quality is compromised.
) Satisfy the temperature at the exit side of the lug rolling mill! In order to increase the extraction temperature of the continuous casting heating furnace, heating equipment, etc., are also required, requiring enormous equipment costs and construction costs.

The present invention achieves the same effect as the method described in F by local heat retention of one piece υ.

In the hot rolling process, the roughness in the longitudinal direction of the slab leaving the continuous slab heating furnace and going to the Bosoto roughing mill is almost uniform, as shown in Figure 1. In a strip, there is usually a temperature distribution in the longitudinal direction as shown in Figure 2. At the beginning of the d-mill biting, the rolling speed is low, so the casting 14 is forced to wait until the force is increased to 11 speeds, and the Strinop temperature decreases. And as the rolling speed is accelerated, the knob temperature increases L, 6.
A water drop usually follows a pattern in which the temperature decreases as it moves through the ridge and reaches the tail. The coldest point or temperature at the lowest point of the tail section before entering this acceleration state is the temperature that is managed as the maximum temperature in terms of coil quality.

Therefore, the present invention improves the conventional method by supplying the slab to the hot rolling mill with the longitudinal side surface portion of the slab corresponding to the coldest point temperature part of the slab kept higher than other portions in advance from the slab stage. Compared to the uniform temperature slab supply of
It is possible to obtain 1 IpA degree.

The temperature in the longitudinal direction of the slab entering the hot rolling mill when no tabs are attached is almost uniform as shown in Figure 1 (on the contrary,
If a part of the insulation layer is pasted, the insulation will be insulated only by the amount of Hjj, resulting in two peaks as shown in Figure 3. Therefore, by pasting the maintenance strip on the side of the slab at the position corresponding to the coldest point of the strip section before acceleration and the coldest point i/j of the tail section of the strip, we solved the problem in section Jl.
Portrait 5. The insulation material should be applied on the side of the slab corresponding to the coldest point slightly inside from the tip of the wrist strip in the longitudinal direction and the coldest point on the tail as described above. The area is
The width is the slab thickness, and the length varies depending on the slab length. In other words, regarding the coldest point at the tip,
From the tip of the slab excluding a length equivalent to 10% of the total length of the slab (hereinafter referred to as 0.IL), the length shall extend to 02L, and from the tail (.
It is effective to apply it over the length of L.

1" in this way, the temperature distribution in the longitudinal direction of the strip when the insulation material is pasted at the time of the slab is compared to the temperature distribution in Figure 2 when nothing was pasted at the time of the slab. As shown in Figure 4, the temperature for 1 minute is the same when no insulation material is attached at the time of slab central part of the strip, but the temperature for 1 minute is 0゛''8''. 41 maintain 6
I can do courage.

In this way, in order to compensate for the temperature at the coldest point and at the tail end at the stripping stage, by applying heat insulating material only to the minimum necessary area by increasing the temperature of the entire slab, Strip-Ets 7 with minimal heat retention consumption.
This is to efficiently ensure temperature.

Therefore, up until now, we have increased the extraction temperature of slab heating furnaces and installed heating devices, heat insulating devices, etc. for the coldest point and the low temperature part of the tail, but by pasting heat insulating material, By increasing the temperature of the coldest point and the tail low temperature part, temperature compensation in the middle of the path is no longer necessary, and a uniform string temperature in the longitudinal direction of the VC can be obtained without consuming a large amount of energy.

Next, we will explain the application of heat insulating material using a specific example.

Figure 5 shows the slabs and slabs that are the object of the present invention, step 1-1) Production of lugs, for each equipment. After being heated in a heating furnace, the slab is made into a small size slab using a breakdown mill 2, hot defects are removed using a hot scarf 3, and heat insulating material is pasted on the necessary parts of the slab using a heat insulating material pasting device 45-. Put it on. After that, a slab glosser 5 is used to shear the defective parts at the front and rear ends, and a scale breaker 6 is used to remove surface scale, and a continuous hot rolling mill 7
If, spread on the strip.

Further, as a heat insulating material pasting device, there is one shown in FIG.

The heat insulating material 8 can be moved horizontally and pasted on the side of the slab 11 by the action of the arm 9 and cylinder 10 attached to the tip, and the two arms 9
, 9 are moved horizontally, respectively, and the slab 11 is
Provide a gap to prevent interference when moving in the longitudinal direction. In the figure, the symbol indicates the maximum slab width, and l indicates the minimum slab width.

Furthermore, heat insulation material 8 is placed on the tip 8I of arm 9! As a means for temporarily adsorbing the material, for example, a suction method using air may be used.

As a result of applying the present invention in this way, the continuous casting material heating furnace extraction temperature can be kept constant, and the temperature can be increased by about 10℃ compared to the case without pasting of insulation material. I was able to do it. Therefore, by applying the present invention, the extraction temperature of the continuous casting furnace for obtaining the conventional string temperature can be lowered by about 50° C., resulting in a great energy saving.

[Brief explanation of the drawing]

1st rMl is a graph of the temperature distribution in the longitudinal direction of the slab in the case of heat retention, 2nd figure is a graph of the temperature distribution in the longitudinal direction of the strip hot-rolled from the slab in 1st figure, 3rd and 4th figure A graph of the longitudinal temperature distribution of slabs and slabs to which the invention is applied, Figure 5 is the subject of the present invention.
Figure 6 is an explanatory diagram of the process of making soy sauce, and Figure 6 is an explanatory diagram of the apparatus for heat insulation and pasting. 1 Slab continuous casting machine 1'-Slab heating furnace z Breakdown mill 3 Hot scarf 4-・Heat insulation material A! I
Device 5. Slab sawyer::: 6 Scale plate no. 7. Hot continuous rolling mill 8 Heat insulation material 9. Arm H1-7 Linder 11 Slab 12. Table roller rod 2 times Ring 3 times Fig. 4

Claims (1)

[Claims] In direct 1F rolling in which continuous casting j4 is string VC rolled without heating, the positions corresponding to the coldest points of the inward leading and trailing ends of the sl IJ saws, that is, the entire length of the slab, are
Then, over the length of 02L from the position excluding the length 011 from the tip of the slab and the length of 02L from the rear end of the slab, the full width e of the slab side surface (a steel material characterized by the ability to paste heat insulating material) Heat retention method during direct rolling.