JPH06246328A - Method for rolling soft metallic slab - Google Patents

Abstract

PURPOSE:To heat and to roll a soft metallic slab without leaving the pawl mark of a pit crane on it. CONSTITUTION:After a double slab 20 in which a soft intermediate metallic slab 12 for rolling is lapped on an underlay slab 11 for extracting and a topping slab 13 for insulating heat are individually charged into a batch type heating furnace 14 and heated, a tripple slab 30 is made by putting the topping slab on the double slab. The tripple slab is extracted from the heating furnace with the pit crane and placed on the roller table of the rolling line and, after the topping slab is fixed with side guides 15, the double slab is advanced on the side of the rolling mill. After the side guides 15 are released, the topping slab 13 and the double slab 20 are retreated on the side of the heating furnace with the roller table and the intermediate slab for rolling is fixed with the side guides. After only the underlay slab for extracting is retreated on the side of the heating furnace, the intermediate slab for rolling is fed to a rolling mill 4 with the roller table and rolled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rolling slabs of soft metals such as mild steel and copper alloys.
The present invention relates to a method for effectively and quickly charging and extracting a soft metal slab into a batch heating furnace before rolling the slab.

[0002]

2. Description of the Related Art Conventionally, a slab of soft metal such as mild steel or copper alloy is first charged into a batch type heating furnace and is heated to a predetermined temperature (7).
70-790 ° C), then extracted, conveyed to a rolling line and rolled by a rolling mill.

For example, as shown in FIG. 3, when extracting a heated soft metal slab 1 from a batch furnace, a pit crane 2 is used to suspend the slab 1 (A). At this time, the claws of the pit crane 2 bite into the softened slab 1 on the side surfaces of the long sides, and the claw marks 3 are left on the slab 1 (3). When this slab 1 is rolled by the rolling mill 4 as it is (C),
The portion of the claw mark 3 appears on the rolled material 5 as a defective portion 6 having an insufficient width (D).

As a result, the yield is lowered and the production efficiency of the rolling line is lowered.

Therefore, as a countermeasure, the slab rolling method is devised (L / C rolling) so that the claw marks of the pit crane appear on the front end or the rear end of the material after rolling (the L / C rolling), and the front and rear ends thereof are used as crops. However, this method requires time for rolling.

On the other hand, when a metal slab such as titanium or titanium alloy having a high temperature dependence of deformation resistance is heated in a heating furnace, a heat resistant cover is placed on the upper surface of the slab to prevent the warpage of the slab. A method has been proposed (JP-A-59-59).
232612).

However, the cover in this method is to prevent the warp of the special metal slab and not to keep the soft metal slab warm. Also, there is no concept of laying the extraction slab under the rolling slab.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a soft metal slab capable of improving rolling efficiency by charging and extracting the slab into a heating furnace without leaving a pit-claw mark on the soft metal slab. The challenge is to obtain a rolling method.

[0009]

A method for rolling a soft metal slab according to the present invention is a method in which a double slab in which an intermediate soft metal slab for rolling is superposed on an underlay slab for extraction and a heat retaining top slab are separately batched. Charging into a heating furnace, and after heating, the heating slab is placed on the double slab in the heating furnace by a pit crane to form a triple slab, and the triple slab is heated by a pit crane. Extracted from the rolling table and placed on a roller table of the rolling line, the triple slab is conveyed to the vicinity of the rolling mill entrance side by a roller table, and after fixing only the heat-insulating slab of the triple slab by a side guide, the roller The double slab is moved forward to the rolling mill side by a table, the side guide is released, and then the heat retaining top slab and Retracting the double slab to the heating furnace side, after fixing only the intermediate slab for rolling of the double slab by the side guide, only retreating the extraction underlay slab to the heating furnace side by a roller table, The problem is solved by means of feeding the rolling intermediate slab to the rolling mill by means of a roller table and rolling the rolling intermediate slab by means of the rolling mill.

It is preferable that the triple slabs are stacked so that the size of the long side of the width or length of each slab becomes larger, middle, and smaller in order from the top.

The extraction underlay slab and the heat retaining upper slab are preferably made of stainless steel.

[0012]

[Function] Since the underlay slab of the triple slab in the heating furnace is sandwiched by the pit crane, no claw marks are left on the intermediate slab for rolling. Since the three types of slabs have different widths or lengths, the slabs are sequentially separated by effectively utilizing the side guides on the rolling mill entrance side.

[0013]

EXAMPLE An example of the method for rolling a soft metal slab according to the present invention will be described with reference to FIG. FIG. 1 is a schematic explanatory view showing the steps of the rolling method of the present invention.

The method of rolling a soft metal slab of the present invention comprises the following steps, as shown in FIG. First,
As shown in FIGS. (A) and (B), the underlayment slab 11 for extraction
The double slab 20 in which the intermediate soft metal slab 12 for rolling is superposed on it and the heat-insulating slab 13 are separately charged into the batch-type heating furnace 14. Next, as shown in FIG. 3C, after heating, the heat retaining mounting slab 13 is placed on the double slab 20 in the heating furnace 14 by the pit crane 2 (FIG. 3) to form the triple slab 30.

As shown in FIG. 2, this triple slab 30 may be stacked so that the size of the long side of the width or length of each slab 11, 12, 13 is large, medium, and small in order from the top. preferable. The dimensional difference at this time is 100
About mm is preferable. In addition, the extraction underlay slab 11 and the heat retaining upper slab 13 are preferably made of stainless steel.

As shown in FIG. (D), the triple slab 30 is extracted from the heating furnace 14 by the pit crane 2 (FIG. 3) and placed on a roller table (not shown) in the rolling line. At this time, the triple slab 30 is set to 9 in order to easily sandwich the extraction underlay slab 11 with the side guides 15 described later.
It may be turned 0 degrees.

As shown in (E) and (F), the triple slab 30 is rolled by a roller table (not shown) into a rolling mill 4.
(FIG. 3) is conveyed to the vicinity of the entrance side, and after the side guide 15 fixes only the heat retaining upper slab 13 of the triple slab 30, the double slab 20 is fixed by the roller table.
To the rolling mill 4 side.

Next, as shown in FIG. 3G, after the side guides 15 are released, the heat retaining upper slab 13 and the double slab 20 are retracted toward the heating furnace 14 by the roller table.

As shown in FIGS. 1H and 1I, only the rolling intermediate slab 12 of the double slab 20 is provided with the side guides 15.
After fixing by, the extraction table slab 11 alone is retracted to the heating furnace side by the roller table.

As shown in (J), the rolling intermediate slab 12 is fed into the rolling mill 4 by a roller table.

Finally, the rolling intermediate slab 12 is rolled by the rolling mill 4.

Specific examples of the method of the present invention are described below.

The dimensions of the various slabs are as follows.

[0024] The product dimensions are 11 mm thick and 2000 mm wide. The heating temperature of the material is 780 ° C. The material components of the intermediate slab for rolling are Cu 60 wt%, Zn 38.5 wt%, S
n1.0 wt%, the balance consisting of unavoidable impurities.

As a result of rolling, the width shortage occurrence rate was zero, the plate warpage occurrence rate during rolling was 5%, and the scale indentation and flaw occurrence rates were 1%.

As a comparative example, a rolling slab (length 1500 m)
m × width 1000 mm × thickness 188 mm) was rolled to a product size of thickness 11 mm × width 2000 mm. The claw trace width concave amount by the pit crane is 50 to 100 mm, the width shortage occurrence rate is 100%, and the plate warpage occurrence rate during rolling is 20%.
%, And the scale indentation flaw was 5%.

[0027]

According to the present invention, no claw marks are left on the rolling slab by the pit crane during extraction from the heating furnace, the temperature drop during transfer to the rolling mill is small, and the warp of the rolling slab can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing steps of a rolling method of the present invention.

FIG. 2 is a plan view of triple slabs stacked in accordance with the present invention.

FIG. 3 is a schematic explanatory view showing steps of a conventional rolling method.

[Explanation of symbols]

 11: Underlay slab for extraction 12: Intermediate slab for rolling 13: Upper slab for heat retention 14: Batch type heating furnace 15: Side guide

Claims (3)

[Claims] 1. A double slab in which an intermediate soft metal slab for rolling is layered on an underlayment slab for extraction and a heating slab for heating are separately charged into a batch type heating furnace, and after heating, by a pit crane. Placing the heat-insulating slab on the double slab in a heating furnace to form a triple slab, extracting the triple slab from the heating furnace by a pit crane and placing it on a roller table of a rolling line, Transporting the triple slab to the vicinity of the rolling mill entrance side by the roller table, after fixing only the heat-insulating slab of the triple slab by the side guide, advance the double slab to the rolling mill side by the roller table, After releasing the side guide, the roller table is used to retract the heat retaining upper slab and the double slab toward the heating furnace, After fixing only the rolling intermediate slab of the slab by the side guide, only the extraction underlay slab is retracted to the heating furnace side by the roller table, the rolling intermediate slab is sent to the rolling mill by the roller table, A method for rolling a soft metal slab, which comprises rolling an intermediate slab for rolling with a rolling mill. 2. The triple slab is stacked so that the size of the long side of the width or length of each slab is large, medium, and small in order from the top. Rolling method. 3. The rolling method according to claim 1, wherein the underlay slab for extraction and the upper slab for heat retention are made of stainless steel.