JPH09285801A - Method and equipment for manufacturing stainless steel shapes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and the equipment for manufacturing efficiently and at a low cost austenitic hot rolled stainless steel shapes (especially thin shapes with a thickness of 3 to 5mm). SOLUTION: (1) A stainless steel strip is heated to 1000 deg.C or over by directly energizing the strip between a feeding roll coming into contact with the strip and a finishing mill, and the rolling of the strip is performed by an intermediate mill and the finishing mill. After finishing the strip at 900 deg.C or over, it is quenched. After energizing the strip in between the feeding roll and the intermediate mill, it is rolled by the intermediate mill. When the tip of the strip is bitten by the finishing mill, after energizing the strip in between the intermediate mill and the finishing mill, and the strip may be rolled by the finishing mill. Before the quenching treatment, if the strip is held for at least one second at 900 to 1060 deg.C, a product characteristic is improved. Also, after the quenching treatment, a straightening treatment may be on-line and continuously performed. (2) Manufacturing equipments for the stainless steel shapes, which are arranged so that materials to be treated are passed through in the order of feeding roll, intermediate mill, finishing mill, quenching device and straightening machine. Before the quenching device, a device for heat insulation and/or heating may be arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing stainless steel bars such as angle steel, I-shaped steel and channel steel using stainless steel strip as a raw material, and manufacturing equipment therefor.

[0002]

2. Description of the Related Art In recent years, there has been an increasing number of cases in which shaped steels made of stainless steel having excellent corrosion resistance are used as aggregates for chemical plants, kitchen equipment and building materials for decoration.

[0003] Conventional methods for producing a stainless steel section include a method for hot rolling from a continuous casting bloom or billet by a hole rolling mill, and a method for cold rolling from a steel plate or strip or press bending. It is roughly divided into a manufacturing method and a manufacturing method.

However, when the cold-formed stainless steel section is used for the above-mentioned applications, especially for decorative building materials,
Since the outer corner R of the corner is large (see FIG. 11),
The problem of poor looking often arises. Therefore, exclusively hot-rolled stainless steel is used.

FIG. 2 is a view showing an example of a conventional rolling roll hole type (pass schedule) which is produced by hot hole-rolling stainless angle steel.

A billet is used as a raw material and a rolling mill having seven hole dies is used to form an angle steel as shown in FIG. 11 by hot rolling with a large number of passes of seven times. However, in this groove rolling, when the material A to be rolled passes through the groove, the roll speed of the part corresponding to the side B of the angle steel (hereinafter also referred to as “flange”) is different, so Severe friction occurs with material A and the surface quality deteriorates.

In addition, the above-mentioned uses, especially JIS S
Austenitic stainless steel such as US304 is used as the material steel, and the thickness of the stainless chevron steel used for the decorative building material is often about 3 to 5 mm. Therefore, due to heat radiation from the material A to be rolled during hot rolling and heat removal to the roll, the temperature of the stainless chevron steel shaped through the finish rolling greatly drops to less than 900 ° C. In this case, even if the so-called "direct solution heat treatment" in which the material is rapidly cooled as it is after rolling, it is not possible to secure desired corrosion resistance and mechanical properties for the product angle steel.

Therefore, in order to secure desired corrosion resistance and mechanical properties, the thin-walled stainless steel chevron steel described above is generally subjected to off-line reheating and solution treatment after hot rolling. It has become a manufacturing method.

FIG. 3 is a view showing an example of a conventional rolling roll hole type (pass schedule) which is produced by hot hole-rolling stainless I-shaped steel. Also in this case, using a rolling mill having 7 holes (6 horizontal holes and 1 vertical hole) using the billet as a raw material, the number of passes is as many as 7 by hot rolling. The I-shaped steel as shown in 12 is formed.

In the case of I-section steel, the web C is particularly thin. Therefore, the temperature drop there becomes extremely remarkable, and the rolling finishing temperature is much lower than 900 ° C. Therefore, in order to secure desired corrosion resistance and mechanical properties, the stainless steel I-shaped steel is also reheated after the hot rolling and subjected to the solution heat treatment as in the case of the thin-walled stainless steel angle steel. The method of application has been adopted.

As is clear from the above two examples, the hot rolled stainless steel section, particularly the thin hot rolled stainless section, has conventionally been reheated offline after hot rolling.
The general manufacturing method has been to perform solution heat treatment. However, when solution heat treatment is applied to the shaped steel, "twist" and "bend" occur in the longitudinal direction of the product. Therefore, it is necessary to perform a straightening process. Due to such off-line solution heat treatment and straightening work, especially in the case of thin-walled hot-rolled stainless steel, the manufacturing process is complicated and the manufacturing cost is high.

Among the problems of the conventional method of hot-rolling stainless shaped steel for hot rolling, a technique for solving the deterioration of surface quality is disclosed in Japanese Patent Laid-Open No. 5-237503. ing. However, in the method proposed in this publication, a forming machine is arranged in front of or behind the hole rolling machine, and rolling is carried out by the hole rolling machine while bending is performed by the forming machine. For this reason, even if the surface texture can be improved, the number of times of shaping including “forming” and “rolling” increases, and the temperature drop of the product is unavoidable. Further, it is inevitable that the manufacturing process and rolling equipment become complicated and the cost becomes high.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is made of stainless steel, especially SUS.
A method for efficiently manufacturing a thin-wall hot-rolled stainless steel section having a thickness of about 3 to 5 mm, which is made of austenitic stainless steel such as 304, at a high temperature by low cost, and a manufacturing facility therefor. The challenge is to provide.

[0014]

Means for Solving the Problems The present inventors have obtained the following findings as a result of various studies to solve the above problems.

If a steel strip is used as the material of the hot-rolled stainless steel section and the heating is performed by direct current heating, the material to be rolled is heated to the final finishing mill (finishing stand).
Even in the case of thin shaped steel products, it is possible to ensure a high rolling finishing temperature of 900 ° C. or higher.

In the heating by direct energization, running (feeding) is stopped in a state where the tip of the steel strip as a raw material is caught in an intermediate mill or finishing mill for modeling, and a portion between the power feeding roll and the intermediate mill, Or, it is done between the power supply roll and the finishing mill. Then, when the temperature of the portion of the steel strip between the power feeding roll and the intermediate mill reaches at least 1000 ° C., rolling is performed by the intermediate mill and the steel strip is re-run at an appropriate speed. Alternatively, when the temperature of the portion between the power feed roll and the finishing mill reaches at least 1000 ° C., rolling is performed by the intermediate mill and the finishing mill, and the steel strip is re-run at an appropriate speed.

When initial heating is performed in the portion between the power feed roll and the intermediate mill, if the tip of the steel strip rolled by the intermediate mill bites into the finishing mill by re-running at the above-mentioned appropriate speed. At the same time, electric heating between the intermediate mill and the finishing mill is also started to perform rolling by the finishing mill.

In the case of performing the initial heating in the portion between the power feeding roll and the intermediate mill, when the intermediate mill is an "intermediate mill group" composed of n mills, the following treatment is performed. . That is, first, the portion between the power feed roll and the m-th intermediate mill is heated to 1000 ° C. or more by direct energization, rolling is performed by the m intermediate mills, and the steel strip is re-run at an appropriate speed. Next, when the tip bites into the (m + 1) th intermediate mill, the mth intermediate mill and (m +
The portion between the 1) th intermediate mills is also heated by direct energization, and is rolled by the (m + 1) th intermediate mills. In the same process, the tip bites into the n-th intermediate mill, the part between the (n-1) -th intermediate mill and the n-th intermediate mill is heated by direct energization, and is rolled by the n-th intermediate mill. Up to. Next, when the tip bites into the finishing mill, the portion between the n-th intermediate mill and the finishing mill is also heated by direct energization and rolled by the finishing mill. Here, m and n are positive integers, and m <n.

If the steel strip is directly heated by electric current by the above-mentioned method, the rolling finish temperature of the shaped steel can always be raised to a high temperature of 900 ° C. or higher.

Furthermore, since heating by direct energization is rapid and short-time heating, generation of scale is extremely small. In other words, the scale loss is extremely small. Therefore,
Even if the rolling front end and the end portion of the steel strip, which is an unsteady portion, are cut off, the yield can be significantly increased as compared with the conventional method for producing a stainless steel section using a material such as bloom or billet.

Since a high finish rolling temperature can be secured,
If the rapid cooling treatment is carried out as it is after the finish rolling, this can be replaced with the conventional solution heat treatment which requires reheating off-line.

After rolling and finishing, if the temperature is maintained at a high temperature or heated to a high temperature, recrystallized grains can be secured and recrystallized grains can be grown.
Corrosion resistance and mechanical properties can be obtained.

If the above-mentioned or rapid cooling treatment (so-called "direct solution heat treatment") is followed by online correction of twists and bends, it is possible to efficiently manufacture stainless shaped steel at low cost.

After the above-mentioned straightening on-line, if the product is further cut on-line to a required length to make a product, the stainless shaped steel can be manufactured at a lower cost and more efficiently.

If a universal mill is used for at least a part of the intermediate mill for modeling, the mill structure becomes compact, the capital investment can be reduced, and the rolling efficiency (production efficiency) is improved.

The present invention based on the above findings is described in the following (1)-
(5) Method for manufacturing stainless steel section and (6), (7)
The manufacturing equipment of

(1) A method for producing a shaped steel from a stainless steel strip by using a shaping mill including an intermediate mill and a finishing mill, wherein a feeding roll and a finishing mill that contact the stainless steel strip with the steel strip A stainless steel section characterized in that the portion between them is heated to 1000 ° C. or more by direct energization, rolled in an intermediate mill and a finishing mill, finished by rolling in a finishing mill at a temperature of 900 ° C. or more, and then rapidly cooled. Manufacturing method.

(2) A method for producing a shaped steel from a stainless steel strip by using a shaping mill consisting of an intermediate mill and a finishing mill, wherein the stainless steel strip has a feeding roll and an intermediate mill which come into contact with the steel strip. The part between them is heated to 1000 ° C or more by direct energization and rolled by an intermediate mill. When the tip is caught in the finishing mill, the part between the intermediate mill and the finishing mill is also heated by direct energization and rolled by the finishing mill. A method for producing a stainless steel section, which comprises quenching after finishing rolling by a finishing mill at a temperature of 900 ° C. or higher.

(3) A method for producing a shaped steel from a stainless steel strip by using a shaping mill comprising an intermediate mill group consisting of n mills and a finishing mill, the stainless steel strip comprising: The part between the power feeding roll and the m-th intermediate mill, which comes into contact with the steel strip, is heated to 1000 ° C or more by direct energization, and is rolled by the intermediate mill of m units, and the tip is (m +
After biting into the 1) th intermediate mill, the part between the mth intermediate mill and the (m + 1) th intermediate mill is also heated by direct energization and rolled by the (m + 1) th intermediate mill. Sequentially until it bites into the nth intermediate mill and is rolled by the nth intermediate mill, then when the tip bites into the finishing mill, the part between the nth intermediate mill and the finishing mill is also heated by direct current to finish. Rolled in a mill,
A method for producing a stainless steel section, which comprises quenching after rolling by a finishing mill at a temperature of 900 ° C. or higher.

However, m and n are positive integers, and m <n.

(4) After finishing rolling with the finishing mill described in any one of (1) to (3) at a temperature of 900 ° C. or higher, it is held in the temperature range of 900 to 1060 ° C. for at least 1 second, Then, a method for producing a stainless shaped steel is characterized by quenching.

(5) A method for producing a stainless shaped steel, characterized in that after the quenching treatment according to any one of (1) to (4) above, a straightening treatment is continuously performed online.

(6) A manufacturing facility for manufacturing shaped steel from a stainless steel strip, in which a power feed roll, an intermediate mill, a finishing mill, a quenching device, and a straightening device are arranged in this order so that the material to be processed passes therethrough. Characteristic stainless steel manufacturing equipment.

(7) A manufacturing facility for manufacturing shaped steel from a stainless steel strip, which comprises a power feeding roll, an intermediate mill, a finishing mill, a device for heat retention and / or heating, a quenching device, and a straightening device in this order. A facility for manufacturing stainless shaped steel, which is arranged so that the material passes through.

The term "quench" used in this specification means J
This is the same as in the "quick cooling", "air cooling", and "gradual cooling" of IS, and refers to cooling at a cooling rate higher than so-called "air cooling", and "forced air cooling" is also included in "quick cooling".

Hereinafter, the above items (1) to (7) are referred to as the inventions (1) to (7), respectively.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The requirements of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an example of manufacturing equipment for carrying out the method for manufacturing a stainless shaped steel of the present invention.
Power feeding roll 1, intermediate mill 2, finishing mill 3, quenching device 4
And straightening machine 5 are arranged in series, and straightening machine 5 is followed by a cutting machine.
6 is also arranged continuously in series (the invention of (6)).

As shown in the figure, a device 20 for heat retention and / or heating may be additionally provided between the finishing mill 3 and the quenching device 4 (invention (7)).

In FIG. 1 described above, the "intermediate mill 2" may be an "intermediate mill group" composed of a plurality of mills. In the following, for simplification, the "intermediate mill group" may also be referred to as "intermediate mill".

First, the case where there is one intermediate mill will be described.

First, the tip of a steel strip S (hereinafter also referred to as "rolled material A"), which is a material of hot-rolled stainless shaped steel,
The mill is stopped when it is bitten into the intermediate mill 2 or the finishing mill 3 via the power feeding roll 1, in other words, the traveling (feeding) of the steel strip S is stopped.

Then, the portion between the power feeding roll 1 and the intermediate mill 2 or the portion between the power feeding roll 1 and the finishing mill 3 is directly energized to start heating. After that, the temperature of the part of the steel strip S between the power feeding roll 1 and the intermediate mill 2 or the part between the power feeding roll 1 and the finishing mill 3 is at least 100.
When the temperature reaches 0 ° C, operate the mill to re-run the steel strip S at an appropriate speed.

That is, regarding the invention of (1), the steel strip is
When the tip of S bites into the finishing mill 3 via the power feeding roll 1, the mill is stopped, and then the portion between the power feeding roll 1 and the finishing mill 3 is directly energized to start heating. After that, when the temperature of the portion of the steel strip S between the power feed roll 1 and the finishing mill 3 reaches at least 1000 ° C., it is rolled by the intermediate mill 2 and the finishing mill 3 and the steel strip S is re-run at an appropriate speed. .

In the case of the invention of (2), when the tip of the steel strip S bites into the intermediate mill 2 via the power feeding roll 1, the mill is stopped, and subsequently, the power feeding roll 1 and the intermediate mill 2
Heating is started by directly energizing the part between them. After this, steel strip
When the temperature of the portion of S between the power feeding roll 1 and the intermediate mill 2 reaches at least 1000 ° C., it is rolled in the intermediate mill 2 and the steel strip S is rerun at an appropriate speed. Then, by re-running at this proper speed, the tip of the steel strip S is finished
At the same time as it is bitten into 3, the electrification heating of the part between the intermediate mill 2 and the finishing mill 3 is started, and rolling is performed by the finishing mill 3.

Next, when there are a plurality of intermediate mills (in the case of intermediate mill groups), m and n are positive integers (where m <n
n).

First, the tip of a steel strip S (hereinafter also referred to as "rolled material A"), which is a material of hot-rolled stainless steel section, is
The mill is stopped at the time when it bites into the m-th intermediate mill constituting the intermediate mill 2 via the power feeding roll 1, in other words, the traveling (feeding) of the steel strip S is stopped.

Then, the portion between the power feeding roll 1 and the m-th intermediate mill is directly energized to start heating. After this,
When the temperature of the portion of the steel strip S between the power feeding roll 1 and the m-th intermediate mill reaches at least 1000 ° C, the mill is operated to restart the steel strip S at an appropriate speed.

That is, in the case of the invention of (3), the steel strip is
When the tip of S bites into the mth intermediate mill via feeding roll 1, the mill is stopped, and then feeding roll 1
And the m-th intermediate mill are directly energized to start heating. After that, when the temperature of the part of the steel strip S between the power feeding roll 1 and the mth intermediate mill reaches at least 1000 ° C, it is rolled by the mth intermediate mills up to the mth, and the steel strip is rolled.
Re-run S at proper speed. Then, the tip of the steel strip S bites into the (m + 1) th intermediate mill by the re-running at the proper speed, and at the same time with the mth intermediate mill ((m +)
1) Also started the electric heating of the part between the 2nd intermediate mill,
Rolling is performed by the (m + 1) th intermediate mill. Such direct electric heating and rolling are sequentially performed until the tip is caught in the nth intermediate mill and rolled by the nth intermediate mill. Next, at the same time that the tip of the steel strip S bites into the finishing mill 3, electric heating of the portion between the n-th intermediate mill and the finishing mill 3 is also started, and rolling by the finishing mill 3 is performed.

In order to carry out direct electric heating, both the intermediate mill 2 and the finishing mill 3 may be structured so as to be insulated by the mill base and the drive device coupling.

The temperature at which the steel strip S is first heated by direct energization must be 1000 ° C. or higher. This is because at a low temperature of less than 1000 ° C., the deformation resistance becomes large and the processing becomes difficult.

By the way, the heating temperature of the steel strip S by direct energization is preferably 1300 ° C. or lower, more preferably 1250 ° C. or lower, in order to suppress the generation of scale and prevent the coarsening of crystal grains. preferable.

The rolling finishing temperature by the finishing mill 3 is 9
It is necessary to secure at least 00 ° C. This is because when the rolling finishing temperature is lower than 900 ° C., precipitation of grain boundary carbides occurs or rolling strain remains, so that the so-called “direct solution heat treatment” in which the material is rapidly cooled after rolling, This is because the corrosion resistance and mechanical properties may deteriorate.

If the above-mentioned heating by direct energization is performed, the rolling finish temperature by the finishing mill 3 is 900
It is extremely easy to secure a high temperature of ℃ or more.

By the way, in order to make the quality of the final product more stable, the rolling finishing temperature is 960 to 106.
The temperature range is preferably 0 ° C.

After the rolling is completed at the high finishing temperature as described above, the solution heat treatment can be carried out on the stainless shaped steel by cooling treatment in the quenching device 4 as it is ((1) to (3)). invention).

As the quenching device 4, for example, a type that is immersed in water or a type that sprays water or mist from a nozzle may be used.

Further, if the so-called "direct solution heat treatment" is followed by straightening and twisting with the straightening device 5, the stainless shaped steel can be efficiently manufactured (the invention of (5)). Of course, the correction may be done offline.
As the straightening device 5, a normal one, for example, a straightening machine composed of 7 rolls may be used.

The cutting to the required size may be carried out continuously online with the cutting machine 6 being arranged next to the straightening machine 5 as shown in FIG. 1 or offline. Cutting machine
6 may be a normal one, for example, a running shear.

By the way, in the case of a manufacturing facility in which the arrangement from the steel strip S to the cutting machine 6 is a series type as shown in FIG. 1, it is possible to install this in a site with a distance of about 20 m. It is possible. In other words, it is much narrower than in the case of equipment using conventional manufacturing methods that use materials such as blooms and billets, heat them and roll them with many hole stands, and then perform solution heat treatment, straightening and cutting offline. It can be placed on the site of the area. Furthermore, the amount of investment in manufacturing equipment can be suppressed.

After the rolling in the finishing mill 3 is completed, if it is held at a high temperature or heated to a high temperature, recrystallized grains can be secured and recrystallized grains can be grown. Therefore, by performing a rapid cooling treatment (solution heat treatment) thereafter, a more stable microstructure and a desired hardness level can be stably obtained, and more stable corrosion resistance and mechanical properties can be imparted to the product ((4 Invention)).

Therefore, for example, a device for heat retention and / or heating is provided between the finishing mill 3 and the water cooling device 4 shown in FIG.
20 may be provided. In this case, heat retention and / or heating is
It is sufficient to maintain the temperature range of 900 to 1060 ° C. for at least 1 second.

When the heat retention and / or heating temperature is lower than 900 ° C., grain boundary carbides are rather precipitated. Therefore, corrosion resistance is deteriorated only by performing so-called “direct solution heat treatment” in which quenching is directly performed after rolling. There are cases. On the other hand, if the temperature exceeds 1060 ° C., the austenite crystal grains may be coarsened and the corrosion resistance and mechanical properties may be deteriorated. Therefore, when heat retention and / or heating is performed after finish rolling, the temperature range may be set to 900 to 1060 ° C.

If the holding time in the above temperature range is less than 1 second, recrystallization may not proceed sufficiently. Therefore, when heat retention and / or heating is performed after finish rolling to impart more stable corrosion resistance and mechanical properties to the product, the holding time in the above temperature range may be at least 1 second. . The upper limit of the holding time is not particularly limited, but it is preferably within 3 minutes in order to suppress the manufacturing cost and further improve the productivity.

After rolling and finishing, heat retention and / or heat treatment in the above temperature range
Or, the equipment for heating is not particularly limited,
For example, a high frequency heating facility or an ordinary electric furnace may be used.

Here, "heating" means literally raising the temperature, but "heat retention" includes not only the case of keeping the temperature at a certain constant temperature but also the case of preventing the temperature from decreasing. . For example, it includes what is called “gradual cooling” which is performed when the temperature drop due to cooling is large.

There is no problem with the mill configuration of the present invention even if the intermediate mill 2 is composed of a plurality of conventional double type mills and the finishing mill 3 is composed of a double type mill.

In the present invention, the material to be rolled is heated directly by electric current until finishing rolling is completed, so that rolling can be performed in a high temperature range and the temperature of the material to be rolled can be greatly lowered. Absent. Furthermore, because of the high temperature rolling, the deterioration of the surface properties due to friction, which is a problem in the conventional method, does not occur.

In the mill structure of the present invention, if the intermediate mill 2 is composed of the universal mill U or the universal mill U and the double type mill H, the mill structure becomes compact and the capital investment can be reduced and the rolling can be performed. Efficiency (production efficiency) is also improved. Therefore, the mill configuration of the present invention is preferably the one described above. Universal mill
When U is used, the driving method may be 2-roll driving, but 4-roll driving is more preferable.

Next, as an example of stainless steel, a. Angle steel, b. I-shaped steel, c. The present invention will be described more specifically with reference to the case of channel steel.

A. Angle iron In the case of stainless angle iron, "look of appearance" is especially important. For this reason, the outside R of the corner portion (see FIG.
In many cases, it is required that the value (see 1) is 1 mm or less.

In order to meet the above-mentioned strict size requirements, it is preferable that the intermediate mill 2 is composed of the universal mill U, or the universal mill U and the double type mill H. The universal mill U may be driven by two rolls, but four rolls are more preferable.

Below, a four-roll drive universal mill
An example of the case of using a modeling mill (intermediate mill 2 and finishing mill 3) composed of U and double mill H will be described.

First, the mill is stopped (the running of the steel strip is stopped) with the tip of the stainless steel strip (rolled material) biting into the universal mill via the power feed roll, and then the feed roll and the universal mill are separated. The part is electrically heated. When the temperature of the portion between the power feeding roll and the universal mill reaches at least 1000 ° C., it is rolled by the universal mill and the steel strip is re-run at an appropriate speed. By re-running at this proper speed, the tip of the material to be rolled bites into the double type finishing mill, and at the same time, the portion between the universal mill and the double type finishing mill is energized to start heating. Roll with a heavy finishing mill. The heating by the direct energization makes it possible to secure a high rolling finishing temperature of 900 ° C. or higher by the finishing mill.

Rolling of the heated stainless steel strip is performed as follows.

The steel strip S (rolled material A) is first pressed down in the width direction by the universal mill U, and the buckling is concentrated in the center of the width, so that the thickness of the central portion is increased as shown in FIG. To be made. Horizontal rolls for universal mill U in this case 7
As for the shapes of 8 and 8, the present inventor has previously proposed Japanese Patent Application No. 6-166614.
As shown in FIG. 4 as proposed in the No. application, ie,
It is preferable that one horizontal roll 7 is provided with a groove 9 at the center of the surface thereof, and the other horizontal roll 8 is provided with a projection 10.

After the steel strip S (rolled material A) is roughly shaped by the universal mill U as described above, as shown in FIG.
By at least one double-roll mill H, the hole-type roll 13 is formed into the angle-shaped steel (see FIG. 11) having the target shape.

FIG. 6 shows an SU having a thickness of 4 mm and a width of 100 mm.
Universal mill with horizontal rolls 7 and 8 and vertical roll 11 as shown in FIG.
The relationship between the width reduction rate and the center thickness increase rate when U is used for width reduction at 1050 ° C. is shown. The “groove depth” in FIG. 6 means the depth of the groove 12 provided in the vertical roll 11 in FIG.

From FIG. 6, in order to increase the thickness of the central portion by 60% or more to obtain the raw material of the angle steel, a vertical width of 17 mm was used for the universal mill with a vertical roll having a groove depth of 10 mm. It can be seen that reduction may be applied at the reduction rate.

B. In the production of stainless steel I-section steel, the intermediate mill 2 may be composed of the universal mill U, or the universal mill U and the double-type mill H, as in the case of the production of the stainless chevron steel. preferable. Regarding the drive of the universal mill U, two roll drive may be used as in the case of the above-mentioned stainless chevron, but four roll drive is more preferable.

However, the universal mill is used as the intermediate mill 2.
When U is used, as shown in Fig. 7, universal mill
The U horizontal rolls may be flat horizontal rolls (14 and 15).

Below, a four-roll drive universal mill
An example of using a modeling mill (intermediate mill 2 and finishing mill 3) composed of U and a double mill H will be described.

First, the mill is stopped (the running of the steel strip is stopped) in a state where the tip of the stainless steel strip is bitten by the universal mill through the power feeding roll, and then the portion between the power feeding roll and the universal mill is electrically heated. . When the temperature of the part between the power feeding roll and the universal mill reaches at least 1000 ° C., it is rolled by the universal mill,
Re-run the steel strip at an appropriate speed. By re-running at this proper speed, the tip of the material to be rolled bites into the double type finishing mill, and at the same time, the portion between the universal mill and the double type finishing mill is energized to start heating. Roll with a heavy finishing mill. The heating by the direct energization makes it possible to secure a high rolling finishing temperature of 900 ° C. or higher by the finishing mill.

Rolling of the heated steel strip is performed as follows.

The steel strip S (rolled material A) is first rolled down by the horizontal rolls 14 and 15 of the universal mill U at the web portion C, and at the same time by the vertical rolls 11 in the width direction. The thickness of (flange B part) can be increased.

After the material A to be rolled is roughly shaped into the I shape by the universal mill U as described above, as shown in FIG.
At least one hole type roll 13 of the double type mill H makes the thickness of the end portion (flange B portion) constant and finishes the I-shaped steel of a predetermined size (see FIG. 12).

FIG. 9 shows a SU having a thickness of 4 mm and a width of 100 mm.
Using the steel strip of S304 as a material, a universal mill U having horizontal rolls 14 and 15 and a vertical roll 11 (however, the depth of the groove 12 provided in the vertical roll 11 is 10 mm) as shown in FIG. The relationship between the width reduction ratio and the plate end portion (flange portion) thickness increase rate when the web portion thickness is 3.5 mm at 0 ° C. and the web portion width is width reduced to 60 mm is shown.

From FIG. 9, in order to increase the thickness of the plate end portion by 20% or more and obtain a raw material of I-shaped steel, a vertical mill with a groove depth of 10 mm was used in the universal mill to obtain a material of 10% or more. It is understood that the reduction may be applied by the width reduction rate.

C. Channel steel The production of stainless channel steel is essentially the same as the production of the above-mentioned stainless chevron and stainless steel I.

However, when the universal mill U is used as the intermediate mill 2, the configuration of the intermediate mill 2 must be composed of the universal mill U and the double type mill H as shown in FIG. This is in the intermediate mill group described above,
This corresponds to the case of n = 2 and m = 1. The universal mill U may be driven by two rolls, but four rolls are more preferable.

As shown in FIG. 10, with respect to the horizontal rolls of the universal mill U constituting the intermediate mill 2, the grooves 18 are provided at the two surface sides near the end of one horizontal roll 16.
However, it is preferable that the other horizontal roll 17 has a shape in which the protrusion 19 is provided.

An example of the case where the intermediate mill 2 (intermediate mill group) is composed of a 4-roll drive universal mill U and a double mill H and the finishing mill 3 is composed of a double mill H explain.

First, the mill is stopped (the running of the steel strip is stopped) in a state where the tip of the stainless steel strip is bitten by the universal mill through the power feeding roll, and then the portion between the power feeding roll and the universal mill is electrically heated. . When the temperature of the part between the power feeding roll and the universal mill reaches at least 1000 ° C., it is rolled by the universal mill,
Re-run the steel strip at an appropriate speed. After that, the tip of the material to be rolled bites into the double-type mill that constitutes the intermediate mill, and at the same time, the electric heating of the portion between the universal mill and the double-type mill is started to start the double-type mill. Rolling by. Next, at the same time that the tip of the material to be rolled bites into the double type finishing mill, energization of the portion between the two double type mills (intermediate mill and finishing mill) is also started, and the double type finishing mill is started. Rolling by. The heating by the direct energization ensures a rolling finish temperature of 900 ° C. or higher by the finishing mill.

Rolling of the heated steel strip is performed as shown in FIG.

That is, the steel strip S (rolled material A) is first rolled down in the width direction by the universal mill U, and the thickness of the two portions near the ends is increased. Then, the grooved steel (see FIG. 13) having the target shape is formed by the hole type roll 13 of the double type mill H constituting the intermediate mill 2 and the finishing mill 3.

Next, as a typical stainless steel, a stainless steel chevron having a thickness of 3 mm and a width of 30 mm is taken,
The present invention will be described in more detail by way of examples.

[0097]

【Example】

(Example 1) Manufacturing equipment whose layout is shown in FIG. 1 (however,
A 4-roll drive universal mill U was used for the intermediate mill 2 and a normal double mill H was used for the finishing mill 3. No heat retention and / or heating device 20 was used. The present invention was carried out according to (1) to produce a stainless angle steel having a thickness of 3 mm and a width of 30 mm.

First, a SU having a thickness of 4 mm and a width of 60 mm is used.
Feeding roll with S304 steel strip at the tip 1
The mill was stopped (the running of the steel strip was stopped) while being bitten into the universal mill U via (a double roll having a roll diameter of 100 mm). The chemical composition of the material, SUS304, is as shown in Table 1.

[0099]

[Table 1]

Next, the power supply roll 1 and the universal mill
The portion between U (length 600 mm) was heated to 1100 ° C. by applying electricity for 10 seconds under the condition of 6V and 3000A.

After that, the mill was restarted and the steel strip was moved to 15 m.
The steel strip is run at a speed of 1 / min, the steel strip is pressed down by 10 mm in the width direction with the universal mill U, and the thickness of the central portion is 5.2 m.
m.

Next, the material to be rolled is treated with a double finishing mill H.
And was rolled into a predetermined angle steel having a thickness of 3 mm. At this time, the tip of the material to be rolled bites into the double type finishing mill H, and at the same time, the part between the universal mill U and the double type finishing mill H is energized under the condition of 6V and 3000A to start heating. , Rolled in finishing mill H. The heating by the direct energization secured 1000 ° C as the rolling finish temperature in the finishing mill H.

The stainless angle steel formed as described above is passed through a quenching device 4 of the type in which water is sprayed in a mist form as it is, to perform so-called "direct solution heat treatment", followed by 7 rolls. A straightening machine 5 was used to correct the twist and bend online.

After this, the cutting machine arranged after the straightening machine 5 is arranged.
Cut online to length by 6. In addition,
1000 mm at the tip and 300 mm at the end, which became unsteady parts during rolling, were cut off.

The SUS304 stainless angle steel product thus obtained was used to measure the proof stress, elongation and hardness (HB) by the usual methods. As a result, the yield strength is 24 kgf / mm ² , the elongation is 48%, and the hardness is HB1.
It was 62, which satisfied the JIS standard.

Further, it was confirmed that the corrosion degree in the sulfuric acid / ferric sulfate corrosion test of JIS G 0572 was equivalent to that when the solution heat treatment by ordinary reheating was performed, and the corrosion resistance was also good.

(Embodiment 2) Manufacturing equipment having a layout in which a high-frequency heating equipment is arranged as a heat retention and / or heating equipment 20 between the finishing mill 3 and the quenching equipment 4 in FIG. 1 (however, an intermediate mill)
The present invention was carried out by using a universal roll U driven by 4 rolls for 2 and an ordinary double mill H for the finishing mill 3) to produce stainless angle steel with a thickness of 3 mm and a width of 30 mm. did.

That is, SUS whose chemical composition is shown in Table 1
Using a steel strip 304 having a thickness of 4 mm and a width of 60 mm as a raw material, angle steel having a thickness of 3 mm was finish-rolled in the same manner as in Example 1. In this example, heating by direct energization ensured a rolling finish temperature of 950 ° C by the finishing mill H.

The finish-rolled stainless steel chevron is then heated for 2 seconds at 975 ° C. by the above high-frequency heating equipment, and then passed through a quenching device 4 of the type in which water is sprayed from a nozzle in a so-called “direct solid solution”. Heat treatment was performed, and then the twisting and bending were straightened online by the straightening machine 5 composed of 7 rolls.

After this, a cutting machine arranged after the straightening machine 5 is arranged.
Cut online to length by 6. In addition,
1000 mm at the tip and 300 mm at the end, which became unsteady parts during rolling, were cut off.

The SUS304 stainless angle steel product obtained as described above was used to measure the proof stress, elongation and hardness (HB) by ordinary methods. As a result, the proof stress is 24 kgf / mm ² , the elongation is 47%, and the hardness is HB1.
It was 63, which satisfied the JIS standard.

Furthermore, it was confirmed that the corrosion degree in the sulfuric acid / ferric sulfate corrosion test of JIS G 0572 was equivalent to that when the solution heat treatment by ordinary reheating was performed, and the corrosion resistance was also good.

[0113]

According to the method for producing a stainless shaped steel of the present invention, the stainless shaped steel, in particular, the thin hot-rolled stainless shaped steel having a thickness of about 3 to 5 mm can be efficiently produced at a low cost. it can. This method for producing stainless shaped steel can be carried out relatively easily using the production equipment of the present invention.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an arrangement of manufacturing equipment for carrying out a method for manufacturing a stainless shaped steel according to the present invention.

FIG. 2 is a diagram showing an example of a conventional rolling roll hole type (pass schedule) produced by hot hole rolling of a chevron-shaped stainless steel.

FIG. 3 is a diagram showing an example of a conventional rolling roll hole type (pass schedule) produced by hot hole-rolling stainless I-shaped steel.

FIG. 4 is a diagram showing an example of a roll arrangement of a universal mill for carrying out the method for producing a stainless shaped steel of the present invention.

FIG. 5 is a view schematically showing how the angle steel is shaped by the hole type roll of the double mill.

FIG. 6 is made of a SUS304 steel strip having a thickness of 4 mm and a width of 100 mm as a raw material, and the universal mill of FIG.
It is a figure which shows the relationship between width reduction rate and center part thickness increase rate at the time of width reduction at 50 degreeC.

FIG. 7 is a diagram showing another example of roll arrangement of a universal mill for carrying out the method for producing a stainless shaped steel of the present invention.

FIG. 8 is a diagram schematically showing how the I-shaped steel is shaped by the hole type roll of the double mill.

FIG. 9 is made of a SUS304 steel strip having a thickness of 4 mm and a width of 100 mm as a raw material and the universal mill shown in FIG.
It is a figure which shows the relationship between a width reduction rate and a plate edge part (flange part) thickness increase rate at the time of making 50 mm of web part thickness into 3.5 mm, and carrying out width reduction of the web part width to 60 mm.

FIG. 10 is a diagram showing another example of roll arrangement of a universal mill for carrying out the method for producing a stainless shaped steel of the present invention.

FIG. 11 is a diagram showing an example of a cross-sectional shape of angle steel.

FIG. 12 is a diagram showing an example of a cross-sectional shape of I-shaped steel.

FIG. 13 is a diagram showing an example of a sectional shape of channel steel.

[Explanation of symbols]

 1: Power supply roll 2: Intermediate mill 3: Finishing mill 4: Quenching device 5: Straightening machine 6: Cutting machine 7, 8, 14, 15, 16, 17: Horizontal roll 9, 18: Groove (of horizontal roll) 10, 19: Protrusion (of horizontal roll) 11: Vertical roll 12: Groove of (vertical roll) 13: Hole type roll 20: Heat retention and / or heating device S: Steel strip U: Universal mill H: Double mill A: Material to be rolled B: Side (flange) C: Web

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B21D 3/05 B21D 3/05 C C21D 1/40 C21D 1/40 A 8/00 9270-4K 8 / 00 E

Claims (7)

[Claims] 1. A method for producing a shaped steel from a stainless steel strip by using a shaping mill comprising an intermediate mill and a finishing mill, wherein the stainless steel strip is provided between a power supply roll and a finishing mill which are in contact with the steel strip. Directly energize the part of 1
A method for producing a stainless steel section, which comprises heating to 000 ° C. or higher, rolling with an intermediate mill and finishing mill, finishing rolling with a finishing mill at a temperature of 900 ° C. or higher, followed by quenching. 2. A method for producing a shaped steel from a stainless steel strip by using a shaping mill comprising an intermediate mill and a finishing mill, wherein the stainless steel strip is provided between a power supply roll and an intermediate mill which are in contact with the steel strip. Directly energize the part of 10
After heating to 00 ℃ or more and rolling with an intermediate mill, when the tip bites into the finishing mill, the part between the intermediate mill and the finishing mill is also heated by direct energization and rolled with the finishing mill. After finishing at a temperature above ℃,
A method for producing a stainless steel section, which comprises quenching. 3. A method for producing a shaped steel from a stainless steel strip using a shaping mill comprising an intermediate mill group composed of n mills and a finishing mill, wherein the stainless steel strip is a steel product. The part between the power feeding roll and the m-th intermediate mill, which comes into contact with the strip, is heated to 1000 ° C. or more by direct energization, is rolled by the m-th intermediate mill, and when the tip is caught in the (m + 1) -th intermediate mill, m-th intermediate mill and (m +
1) The part between the intermediate mills is also heated by direct energization and rolled in the (m + 1) th intermediate mill until the tip is caught in the nth intermediate mill and rolled in the nth intermediate mill. Then, when the tip bites into the finishing mill, the part between the nth intermediate mill and the finishing mill is also heated by direct energization and rolled by the finishing mill, and rolling by the finishing mill is completed at a temperature of 900 ° C. or higher. Then, a method for producing a stainless shaped steel, characterized by performing a rapid cooling treatment. However, m and n are positive integers, and m <n. 4. After finishing rolling by the finishing mill according to any one of claims 1 to 3 at a temperature of 900 ° C. or higher, it is held in a temperature range of 900 to 1060 ° C. for at least 1 second and then quenched. A method for manufacturing a stainless steel section, which is characterized by the above. 5. A method for producing a stainless shaped steel, characterized in that after the quenching treatment according to any one of claims 1 to 4, a straightening treatment is continuously performed online. 6. A manufacturing facility for manufacturing a shaped steel from a stainless steel strip, characterized in that a feed roll, an intermediate mill, a finishing mill, a quenching device, and a straightening device are arranged in this order so that the material to be treated passes therethrough. Equipment for manufacturing stainless steel section. 7. A manufacturing facility for manufacturing a shaped steel from a stainless steel strip, which comprises a feed roll, an intermediate mill, a finishing mill, a device for heat retention and / or heating, a quenching device, and a straightening device in this order. A facility for manufacturing stainless shaped steel, which is arranged so that