JPH02151301A - Method for rolling shape steel - Google Patents

Abstract

PURPOSE:To prevent shape defects such as web buckling and to obtain shape steels with the web of a constant height by making a drafting ratio in joining regions of a web and flanges larger than that for other regions in a 1st pass and drafting the web by adjusting a roll width and a roll gap in a 2nd pass. CONSTITUTION:In a 1st pass, a rolled stock is drafted to reduce a web height of the shape stock by making a drafting ratio in joining regions of a web ha and flanges hb of a shape stock (h) larger than that for other regions. In a 2nd pass, the web ha is drafted to reach a target reduction amount by properly adjusting a roll width of a segmented roll 4a and a roll gap of drafting rolls 4a. In the final pass, uniform drafting to mainly correct a web and a flange thicknesses, and a sectional shape of the stock is performed. Thus, shape defects such as overlaps in joining parts of the web and flanges and web buckling are not generated and good rolling is performed.

Description

Detailed Description of the Invention (Industrial Application Field) This invention is particularly useful when rolling H-shaped, groove-shaped, or ■-shaped shaped steel, especially when the outer width (web height) of the cough shaped steel is rolled within the same rolling chance. This paper attempts to propose a rolling method that can be freely adjusted. The rolling of H-section steel will be explained below as an example.

(Prior art) Conventionally, when manufacturing H-section steel by rolling (hereinafter referred to as roll H), rolls of the same width are used at the same rolling chance, so the inner width of the H-section steel can be kept constant. When changing cross-sectional dimensions such as flange thickness, the web height changes accordingly, so there were many products in the same series whose nominal dimensions and web height did not match. When manufacturing H-shaped steel here by welding (build-up H)
Because they use thick plates of a predetermined size, the web height can be kept constant even if the cross-sectional dimensions change in the same series, but in the roll H as described above, the cross-sectional dimensions of the section steel necessitated frequent replacement of rolling rolls and guides.

For example, Japanese Patent Application Laid-Open No. 1983-1989 is a document related to rolling of H-beam steel.
Japanese Patent No. 178101 discloses a rolling method in which the web portion of a profile is partially rolled and the web height can be freely adjusted without replacing rolling rolls or the like.

(Problems to be Solved by the Invention) However, with the technology disclosed in the above-mentioned publication, the roll surface pressure increases significantly during partial rolling, resulting in an excessive load being applied to the rolling mill, and the amount of width expansion is limited by the amount of protrusion of the web. receive,
Another problem was that it was difficult to widen the web in areas where the web thickness was large.

It is an object of the present invention to propose a new rolling method in which the web height can be freely adjusted within the same rolling chance without incurring the above-mentioned disadvantages in rolling section steel.

(Means for Solving the Problems) The present invention provides a method for manufacturing a section steel by subjecting a section having a web and a flange that has undergone breakdown rolling to rough universal rolling and then finish universal rolling. Using a universal mill equipped with split rolls with variable width that sandwich the web of the profile vertically, and a reduction roll that controls the reduction of the web height of the profile, the first bath is to cut the flange of the profile Rolling is performed in the direction of reducing the web height within a range that does not exceed the buckling limit by increasing the rolling reduction ratio of the joint area with the web than other parts, and in the subsequent second pass, the roll width of the split roll and the rolling roll are It is characterized by further rolling in the web height and reduction direction until the target reduction amount is reached while adjusting the roll gap appropriately, and then, in the final pass, uniform reduction is applied over the entire cross section of the section for finish rolling. This is a method of rolling steel sections.

(Function) Now, Fig. 1 shows a schematic of rolling equipment for H-beam steel.
2 is a breakdown rolling mill that roughly shapes materials such as bloom into a predetermined cross-sectional shape; 2 is a rough universal rolling mill;
3 is an edge rolling mill, and 4 is a finishing universal rolling mill. A vertical roll 4b that rolls down in the width direction is provided.

On the line shown in Figure 1 above, in order to adjust the profile after rough universal rolling to a predetermined web height in finish rolling, as shown in Figures 2 (a) and (b). Finishing The roll width A of the split rolls 4a disposed in the universal rolling mill 4 is adjusted in advance to the inner width l of the H-beam to be rolled, and the vertical rolls 4b are used to roll the vertical rolls 4b to the height of the web ha. It is extremely effective to roll down in the direction of reducing the size.

However, such a rolling method may cause the following problems.

1) When the amount of web height reduction is large, the web buckles when reduced in one pass, and cannot be corrected in a later process.

2) It is difficult to balance the reduction of the web portion and the flange portion, and web waves may occur, the flange width may be uneven, and the profile may meander.

3) The profile is not easily caught in the rolling mill.

Therefore, in this invention, when reducing the web height of the profile, in order to reduce the amount of reduction per pass,
It was decided to roll it in passes.

Specifically, the first bus consists of the profiled web h1 and flange h.
, the rolling reduction rate of the joint area with the rolling part is made larger than that of other parts, and the web height of the profile is rolled down in the direction of reducing the web height, and in the second pass, the roll width of the split roll 4a and the roll gap of the rolling roll 4a are adjusted appropriately. While making adjustments, it is rolled down until the target reduction amount is reached, and in the final pass, a uniform reduction is applied that mainly adjusts the web thickness, flange thickness, and cross-sectional shape of the profile.

The reason why the rolling reduction ratio of the joint area between the web h and flange h of the profile is made larger than other parts in the first bus is that when reducing the web height of the profile, a third This is to prevent the formation of dents as shown in the figure. In order to perform such rolling, the roll shape of the rough universal rolling mill 2 must be devised to prevent the joints of the profile from forming in advance during the rough universal rolling stage. This can be easily handled by making the wall thicker than other parts as shown in FIG.

(Example) In the equipment shown in Fig. 1, a H-420X 197X9.2X18.5 shape that has undergone rough universal rolling is finished rolled at 1st pass 410X9.2X18.42nd bus
401 X9. I X1B, 23rd pass 400
x9. Reverse rolling was performed under the conditions of Ox18.0 to produce H-section steel having a size of H400x200x9x1B, and the cross-sectional shape of the resulting product was investigated.

As a result, despite the total reduction of 20 mm, good rolling was possible without shape defects such as bending near the joint between the web and flange and buckling of the web. It was confirmed that it was possible to freely change the web height by rolling down the web portion of the profile in its width direction.

Next, the product size is H-400x200 x 6
9 section steel and H-400x 200 x 12 x 24
Size H-430X197X12.2 was subjected to rough universal rolling in order to produce the same shape steel within the same rolling opportunity.
A shape material having a shape of A reduction of 6 mm was performed. As a result, no folding or the like was observed near the R portion. Conventionally, the limit reduction amount in one pass was up to about the web thickness, but by following the present invention,
．． It was possible to enlarge the image up to about 5 times.

(Effects of the Invention) According to the present invention, 1) a steel section with a constant web height can be manufactured with a small number of rolls, similar to Buildup H, without causing deterioration of shape such as buckling of the web portion; For webs with small size differences in height, rolling rolls can be shared, eliminating roll chances, shortening roll chance cycles to shorten delivery times, and reducing costs by reducing roll unit consumption and roll assembly work. realizable.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the layout of manufacturing equipment for H-beam steel, Figures 2 (a) and (b) are schematic diagrams showing the rolling status of a profile during finish rolling, and Figures 3 and 4 are diagrams showing the profile. It is an enlarged view of the main part. 1... Breakdown rolling mill 2... Rough universal rolling a 3... Edger rolling mill 4... Finishing universal rolling mill 4a... Split roll 4b... Vertical roll h... Profile ri, ... web h, ... flange Fig. 2 (b)

Claims (1)

[Claims] 1. When producing a section steel by applying rough universal rolling and then finish universal rolling to a section having a web and flanges that have undergone breakdown rolling, rolls that sandwich the web of the section between the top and bottom of the section after rough universal rolling are used. Using a universal mill equipped with a split roll whose width can be changed and a reduction roll that controls the reduction of the web height of the profile, the first pass is to reduce the reduction ratio of the joint area between the flange of the profile and the web. The web height of the section is rolled down in the direction of reducing the web height of the section, and in the subsequent second pass, the roll width of the split rolls and the roll gap of the reduction rolls are adjusted appropriately until the target reduction amount is reached. A method for rolling a section steel, characterized in that the section steel is further rolled down in a direction to reduce the web height, and then, in the final pass, uniform rolling is applied over the entire cross section of the section section for finish rolling.