JPH0262322B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a channel steel having a flange portion parallel to the billet by combining channel hot rolling and cold forming.

Generally, when producing a channel steel using common steel as a material, the channel steel is formed into a desired final shape by hole hot rolling. However, stainless steel, especially austenitic stainless steel such as SUS304, has poor deformability compared to the above-mentioned steels, has high deformation resistance at high temperatures, and is prone to seizure, so it is difficult to use the above-mentioned hole hot rolling method. When molded, the product had drawbacks such as a large number of surface defects and premature wear of the rolling rolls, making it impossible to put it to practical use.

Therefore, conventionally, when manufacturing channel steel using stainless steel such as SUS304, two angles are arranged parallel to each other in the longitudinal direction, butt welded, and then the front and back sides are The formed beads are removed by cutting to produce channel steel.

In this way, stainless steel channel steel has traditionally been manufactured by welding, despite its low productivity and extremely high cost.In recent years, stainless steel channel steel has been used as a construction material. ,
In conjunction with the increasing demand for decorative materials, there has been a strong demand for the development of an inexpensive manufacturing method for stainless channel steel.

The present invention was made in view of the above-mentioned drawbacks in conventional groove rolling and universal rolling. This study was developed by taking into consideration the material factor that seizure easily occurs, and the forming factor that a large difference in roll circumferential speed occurs at the flange during rolling, making seizure easy to occur at the flange. It is a completed invention.

The present invention combines two processes of groove hot rolling and cold forming in manufacturing channel steel.
It is an object of the present invention to provide a method for manufacturing channel steel at low cost without causing defects such as seizure on the surface.

That is, in the present invention, a rolled material heated to a predetermined temperature is rolled by a plurality of sets of rolling rolls each having a predetermined hole shape, so that in a cross section perpendicular to the longitudinal direction, the web portion is formed in an arc shape between the flange portions. The flange portion extends 15 to 15 mm outward from both ends of the web portion with respect to a perpendicular to a line connecting both ends of the web portion.
It has a linear shape inclined at 75 degrees, in other words, the shape in the cross section is W-shaped, and the wall thickness of the flange part and web part is the same as that of the flange part and web part of the channel steel to be manufactured. a first step of molding an intermediate product having a wall thickness approximately equal to that of the intermediate product; and a plurality of sets of cold forming rolls, each pair of forming rolls sandwiching the arc-shaped web portion of the intermediate product to form the web. This method is characterized by comprising a second step of forming a channel steel having a parallel flange portion and a flat web portion by performing cold forming processing to flatten the portion.

To explain this in more detail, in the first step, an intermediate product having a W-shaped cross section perpendicular to the longitudinal direction is formed from a rolled material such as a billet by groove rolling. A plurality of sets of rolls, at least one of which is rotated by a drive device, are used, and in order to reduce the difference in circumferential speed of the rolls at the flange section, the flange section is set perpendicular to the line connecting both ends of the web section in the cross section. The material is inclined outward from the line and hot rolled using a pass schedule as shown in FIG. Furthermore, in the second step, the cross section becomes W
When cold rolling a channel steel having parallel flanges and a perpendicular flat web from an intermediate product, the workpiece material, austenitic stainless steel, has the property of being significantly work hardened by cold working. Considering that it is difficult to obtain the desired processing amount in one pass, the number of passes using cold rolls arranged parallel to each other is set at least two passes, and the convex-shaped web part is formed in stages. Molded,
This is a flat web part that prevents partial thickness changes in the intermediate product due to improper processing or flaws in the product.

In addition, the inclination angle of the flange part of the intermediate product processed into a W-shaped cross section in the hole hot rolling process is
In the cross section, the web portion is inclined outward by 15° or more with respect to a line perpendicular to a line connecting both ends of the web portion.
The reason why the inclination angle was set to 75° or less was to reduce the difference in roll circumferential speed at the flange during rolling and prevent seizure from occurring at the flange.
This is because if the flange portion opens outward more than this, it becomes difficult to process the flange portion at right angles to the web portion during cold working. In addition, the radius of curvature of the convex web portion formed inside the flange portion of the intermediate product must be at least 2 times the plate thickness of the web portion.
The reason why it is set to more than double this is because if it is less than this, when the web portion is flattened by cold rolling, work hardening will occur locally in the initial stage of forming, and a good flat portion will not be obtained.

Furthermore, in cold rolling, pinch rollers are provided before and after the cold rolling as necessary. This improves the bite of intermediate products,
This prevents the forming roll from slipping. Note that cold working is working in a temperature range below the recrystallization temperature, and also includes warm working.

The present invention will be explained below based on one embodiment thereof.

The present invention first uses a plurality of sets of rolling rollers arranged parallel to each other and having a predetermined groove shape, at least one of which is rotated by a drive device, to achieve a pass schedule as shown in FIG. Therefore, an intermediate product is formed from the billet.

In Fig. 1, 1 is a billet, 2 is an intermediate product with a W-shaped cross section, 3 is a flange part of the intermediate product 2, and 4 is an arc-shaped web part that bulges between both flange parts. . FIG. 2 shows final rolling rolls with predetermined grooves, which are arranged parallel to each other and whose lower parts are rotated by a drive device (not shown), for forming an intermediate product with a W-shaped cross section. , 5 is an upper roll, 6 is a driving roll, and 7 is a hole type.

FIG. 3 is a schematic diagram of a plurality of sets of forming rolls arranged parallel to each other and having a desired roll shape, used for cold rolling an intermediate product 2 having a W-shaped cross section; 12 is a pinch roller on the input side, 13 is a pinch roller provided on the upper side, and 14 is a cylindrical type roll provided on the lower side.

According to the present invention, in the first step, the billet 1 heated to a predetermined temperature and having a cross-sectional shape shown at 1 in FIG. The flange portions 3 are integrally formed at both ends of the web portion 4 in a W shape as described above by the final rolling roll shown in FIG. 2, as shown in FIG. 1. An intermediate product 2 with a cross section shown in 7 is formed.

The web portion 4 of this intermediate product 2 is formed between the flange portions 3 into an arcuate cross-sectional shape that bulges out in the shape of a convex portion with respect to a straight line connecting both ends of the web portion 4 which are the connection portions with the flange portion 3, It is formed to have a uniform thickness that is almost the same as the web section of the channel steel of the final product to be manufactured. The flange portion 3 of this intermediate product 2 is formed into a linear cross-sectional shape inclined outward from the perpendicular line of the line connecting both ends of the web portion 4, and is a flange of the channel steel of the final product to be manufactured. It is molded into the same shape with almost the same wall thickness as the part. The degree of inclination of the flange portion 3 is such that at both ends of the web portion 4, the flange portion 3 is inclined at an angle of 15 to 75 degrees to the outside of the web portion 4 with respect to a line perpendicular to a line connecting both ends of the web portion 4. .

Next, in the second step of the present invention, the web portion 4 of the intermediate product 2 is flattened and cooled using cold forming processing equipment equipped with a plurality of pairs of cold forming rolls having mutually parallel rotation axes. Form in between. This cold forming roll is used to form the web portion 4 of the intermediate product 2.
A pair of forming rolls consisting of a chain-shaped roll 13 and a cylindrical-shaped roll 14 each having a forming surface formed on the circumferential surface with a diameter larger than the diameter of the arcuate cross section, and a pair of forming rolls having a flat cylindrical forming surface. A forming roll having a forming surface with a diameter gradually increasing in diameter is disposed between both forming rolls as necessary, and the web part 4 of the intermediate product 2 is cold-formed to form a uniform meat. Form into a thick flat shape.

In this second step, as the web portion 4, which was curved in an arc shape in the intermediate product, is gradually formed into an arc shape with a larger diameter, the flange portion 3 becomes perpendicular to the line connecting both ends of the web portion 4. Stand up in the direction,
When the web portion 4 is molded flat, the flange portion 3 stands perpendicularly to the flat web portion 4, and both flange portions 3 are molded to be parallel to each other. In order to ensure this, in the cross section of the intermediate product 2 shown in FIG.
The outer surface of the flange portion 3 is formed at its lower end so that a line drawn perpendicularly to the longitudinal direction of the flange portion 3 becomes a tangent to the curve of the lower surface of the connection portion of the web portion 4 with the flange portion 3 which is curved in an arc shape. Next, the groove shape of the final rolling roller shown in FIG. 2 was determined. Further, the distance between the forming surfaces of the cold working rolls is made equal to the wall thickness of the web portion of the channel steel of the final product.

As an example, a billet with a cross-sectional side of 50 mm and a length of 1000 mm is heated to 1050°C, and this billet is rolled into a flange portion using a rolling roll with a predetermined hole shape according to the pass schedule shown in 1 to 7 in Figure 1. 3 is successively hot-rolled without seizure, and the thickness of the flange portion 3 and the web portion 4 is approximately equal to the thickness of the flange portion and the web portion of the channel steel of the desired final assembly, and a pair of The flange portion 3 has a shape that is inclined outward at 45 degrees with respect to a line perpendicular to a line connecting both ends of the web portion 4, and the radius of curvature of the arcuate web portion 4 is three times the thickness of the web portion 4. An intermediate product 2
was formed in the first step, and then in the second step, the intermediate product 2 was held between pinch rollers 11 and passed through the web portion 4 through three passes with cold forming rolls 13 and 14 to form it flat. In this second step, the web part is cold-formed flat without any thickness change, and the flange part is also free from surface flaws, and a channel steel is manufactured that is perpendicular and parallel to the flat web part. Ta.

According to the present invention, in the first step, the rolled material is hot-rolled by a rolling roller having a predetermined groove, so that the web portion bulges out in an arc shape between the flange portions in the cross section of the rolled material. , the flange portion has a linear shape that is inclined outward at an angle of 15 to 75 degrees with respect to the perpendicular to the line connecting both ends of the web portion, and to put it simply, it is W-shaped;
By molding an intermediate product in which the wall thicknesses of the flange portion and web portion are approximately equal to the wall thicknesses of the flange portion and web portion of the channel steel to be manufactured, the shape, length, and shape of the flange portion in the cross section are The wall thickness is almost the same as the flange part of the channel steel that is the final product, and the length and wall thickness of the web part that bulges in an arc shape are the same as the length and wall thickness of the web part of the channel steel that is the final product. An intermediate product with approximately the same thickness is obtained. In this first step, in the cross section perpendicular to the longitudinal direction of the intermediate product, the flange part has a W shape that is inclined outward at an angle of 15 to 75 degrees with respect to the perpendicular to the line connecting both ends of the web part. As a result, the difference in roll circumferential speed at the flange portion during rolling is reduced, and intermediate products do not suffer from surface flaws or seizures due to hot rolling, and are prone to seizures like austenitic stainless steels. Even when steel is used as a rolled material, there is no risk of seizure.

According to the second step of the present invention, the intermediate product is cold-formed by a plurality of sets of cold-forming rolls in which the arcuate web portion is held between a pair of forming rolls in each set to flatten the web portion. As the web portion of the intermediate product, which had been formed into an arc shape, is flattened by the forming process, the flange portions that were slanted outward at both ends of the web portion gradually stand up, and the web portion becomes flat. When cold forming is completed, the final product is a channel steel with flanges perpendicular to the web and erected at both ends of a straight and flat web in a cross section perpendicular to the longitudinal direction. molded. This second
The process is a cold forming process in which the arcuate web part of the intermediate product is flattened using cold forming rolls.It can be formed with good dimensional accuracy, and there is no need to straighten the flange part after the cold forming process, resulting in high strength. A channel steel having the following properties is obtained. Particularly in the case of workpiece materials such as austenitic stainless steel, which are significantly work-hardened by cold working, preferable strength due to work hardening can be obtained by using cold forming as the second step to form the final product. .

As mentioned above, the present invention manufactures an intermediate product with a W-shaped cross section in the hole hot rolling process, thereby producing a product that has poor deformability like austenitic stainless steel and is highly prone to seizure. Even easily rolled steel can be hot-rolled without surface flaws, and even in cold rolling, by using a combination of truss rollers and cylindrical rollers, intermediate products with a W-shaped cross section can be rolled with a thickness. A channel steel having parallel flange portions can be manufactured without any change, and it can be manufactured at a significantly lower cost than conventional channel steel made by welding angles.

Furthermore, when producing channel steel using the groove rolling method using ordinary steel as a raw material, it is common to apply lateral pressure to the flange part in order to improve the overhang of the wall in the finishing hole die. Galling tends to occur in the flange part, and to prevent this, the flange part is usually rolled with a slight taper, and the taper remains in the flange part of the channel steel manufactured by the above rolling method. It is. In contrast, in the method of the present invention, lateral pressure is applied with the flange section inclined outward at an angle of 15° or more with respect to the perpendicular line, so there is no fear of galling of the flange section, and unlike the conventional method, the flange section is not affected by galling. There is no need to provide a taper, and thus the method of the present invention has high practicality.

[Brief explanation of drawings]

Figure 1 shows the pass schedule for manufacturing intermediate products from billets, Figure 2 shows the final rolling roll shape, and Figure 3 shows the rolls and pinch rollers used for cold rolling. This is a schematic diagram, and FIG. 4 shows the shapes of a pinch roller and a cylindrical roller used in cold rolling. 1: Billet, 2: Intermediate product, 3: Flange part, 4: Web part, 5, 6: Roll roll, 7: Hole type, 11, 12: Pinch roller, 13: Tsume type roller, 14: Taiko type roller .

Claims (1)

[Claims] 1. In manufacturing a channel steel in which flange portions are erected perpendicularly to the web portion at both ends of a straight flat web portion in a cross section perpendicular to the longitudinal direction, Rolling is performed on a rolled material heated to a predetermined temperature by a plurality of sets of rolling rolls having predetermined hole shapes, so that the web portion bulges out in an arc shape between the flange portions in the cross section, and the flange portion should have a linear shape inclined outward from both ends of the web part by 15 to 75 degrees with respect to the perpendicular line connecting both ends of the web part, and the wall thickness of the flange part and the web part should be manufactured. A first step of forming an intermediate product approximately equal in thickness to the flange portion and web portion of the channel steel, and forming an arc-shaped web of the intermediate product using a plurality of sets of cold forming rolls, each with a pair of forming rolls. A second step of forming a channel steel having a parallel flange part and a flat web part by applying cold forming processing to flatten the web part by sandwiching the parts. Production method. 2. The method according to claim 1, wherein in the first step, the radius of curvature of the arcuate web portion in the cross section is at least twice the wall thickness of the web portion. Method of manufacturing channel steel.