JPS5947607B2 - Edger hole type of steel plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a one-hole edger type in edger rolling for the purpose of changing the width of a steel plate.

Continuous casting technology has advanced significantly in recent years, and many slabs for steel plates are now manufactured by continuous casting.

However, the manufactured steel plates come in various widths as well as thicknesses, and in order to obtain these products, the dimensions of the material must be changed accordingly.

Among these, the thickness of the product can be adjusted to a wide range in the subsequent rolling process, so the material thickness is relatively uniform.

However, with regard to product width, for example, strip products have a wide range of widths from 2.5 ft to 7 ft, but there is a problem of whether this width adjustment is performed in the rolling process or in the material manufacturing process.

In the past, ingots were bloomed and rolled to make slabs, so this width adjustment could be done in the blooming process and did not pose much of a problem.However, with the shift to continuous casting, it has become difficult to adjust the width in the material manufacturing process. The casting mold had to be changed,
This hinders the economic efficiency of continuous casting.

Therefore, various width rolling methods have been studied in order to change the slab width in the rolling process, and the well-known hole type edger method has been proposed.

Various studies were also conducted regarding the groove shape in this case, and for example, the Japanese Patent Publication Publication No. 47-3
No. 6619 and Japanese Patent Publication No. 50-14632.

However, the single hole type edger has various problems such as roll wear, roll seizure, and occurrence of scratches due to bite from the hole type.

An object of the present invention is to determine a hole size that causes less roll wear and does not cause roll seizure or bite defects by investigating in detail the material deformation behavior during edge rolling.

The conventional edger single-hole type, as typified by Japanese Patent Publications No. 47-36619 and Japanese Patent Publication No. 14632-1982, has the following characteristics.

(a) The hole shape is a flat bottom caliber or a convex bottom caliber as shown in Figure 1 a and b.

(b) In that case, the caliber part depth B1, caliber bottom width H, and caliber slope inclination angle α are approximately the following values.

fL: River partial depth B: 50-600 Caliber bottom width H 80-100% of nislab thickness River slope inclination angle α: 2-12° On the other hand, we investigated the phenomena caused by these rolls in detail. The following was discovered.

(a) Roll wear and roll seizure are caused by the fact that the caliber bottom width is 80 to 100% of the slab thickness, which is less than the slab thickness.

(b) The flaws due to bite from the hole mold are due to the fact that the appropriate caliber bottom depth B for the width reduction amount has not been determined.

The inventors of the present invention have conducted a detailed investigation into the material deformation behavior during edger rolling and have clarified the following, thereby discovering hole dimensions that do not have the above-mentioned problems.

That is, when the material is edge-rolled using flat rolls without grooves, a dogbone 1 as shown in FIG. 2 is formed in the material, but in the case of a steel plate, the dogbone 1 is bent as shown below.

(a) Dog bone edge width h2 When edge rolling is performed using flat rolls, the width h2 of the edge portion is expressed as the ratio h2/h to the material thickness ho, and the width h2 is expressed as shown in Fig. 3 with respect to the width reduction ratio. It becomes a relationship.

In other words, due to width reduction, the edge part of the rolled material is 2 to 20 times the thickness of the material.
Chi also increases.

However, in the conventional single-hole type edger, this part is constrained to a thickness of 80 to 100 mm thicker than the material, which places an excessively large load on the slope of the bottom of the caliber.

This causes significant wear on the bottom slope of the caliber.

At the same time, the maximum position angle α' of the dogbone is 5° to 15° relative to the width reduction ratio, as shown in Figure 4, which is 2° to 12° compared to the conventional
It was also found that ′ was slightly too small and the dogbone of the rolled material was being restrained too much, which also promoted roll wear and roll seizure.

(b) Highest position of dog bone When the position where the dog bone is highest, for example, point A in FIG. 2, is examined with respect to rolling conditions, the relationship as shown in FIG. 5 is obtained.

Figure 5 shows the distance B from the edge of the highest position of the dogbone.
g, the ratio Bg/B 1 of the plate width Bl after rolling, and the ratio 1ti/13H1 of the projected contact arc length 7d and the average plate width Bm, which is a linear relationship as shown in equation (1). It is shown that.

Bg=B1=A ・(td/Bm)+C-(1) Therefore, Bg=(A・(td/Bm) 〇)・Bl・・・・・・
(2) Here, A and C are constants that vary depending on the sheet width, caliber shape, roll lubrication, rolling speed, rolling temperature, etc., and are approximately the following values under the hot rolling conditions of the steel sheet.

A=0.05-0.3 (appropriate range C=1.0-0.8 A=0.I C=0.
9) However, many rolling test results show that in edger rolling, in order to prevent the rolled material from biting out of the hole die, the edger caliber bottom width H must be 1 of Bg calculated by equation (2).
．． It was found that 0 to 2.0 times more is required.

As a result, the present inventors have found the following hole size as a hole shape that causes less roll wear and does not cause roll seizure or bite-out flaws.

That is, the gist of the present invention is as follows.

In a steel plate hole type edger, the bottom width of the caliber has a width of 101 to 120% of the thickness of the powder material, the inclination angle of the caliber slope is 5° to 20°, and the depth of the caliber part is according to the following formula: A steel plate edger pressure hole type having a hole size that is 1.0 to 2.0 times the required Bg.

Bg=(A・(,td/Bm)+C)・Bldan, A: constant determined by rolling conditions such as plate width, caliber shape, roll lubrication, rolling speed, etc. C: plate width, caliber shape, roll lubrication, rolling speed Constant B1 determined by the rolling conditions such as: Target plate width after rolling td: Projected contact length Bg: Distance from the maximum thickness position of the dog bone shape cross section to the slab edge 1) The friction of the rolls, especially the friction of the inclined surface of the caliber, is greatly reduced.

(il) Elimination of roll seizure.

(iii) Since the material is no longer squeezed out of the hole mold, flaws caused by the squeeze-out are no longer generated.

(IV) This eliminates the problems encountered during groove edger rolling and further improves the merits of width intensive rolling using an edger.

Example (1) The test was carried out using a strip line shown in FIG. 6, where 2 indicates a heating furnace.

(11) Materials used: Ultra-low carbon steel CC slab 250tX1250WX10mm mm Unit weight 24 Ton (iiD Final product size 3, OtX1120WXL mm - (IV) Edger used for hole type - E1 mil (V)
The caliber used is shown in Figure 7 (vi) Amount of width loss due to the edger 90-125 11) 350,000 tons of strip was rolled in the above actual rolling line, but (a) the amount of roll friction was extremely small ( (b) Roll seizure - None flaws due to bite - None V11υ This has further improved the merits of width rolling. (a) Conventionally, material widths were prepared every 50 mm, but
This was done every 100 rrvn, which had a great effect on reducing operating costs, such as reducing the number of materials prepared (b) improving the per-unit consumption of edger rolls, and c) improving the test yield.

[Brief explanation of the drawing]

Figure 1 a and b are explanatory diagrams of a conventional edger single-hole type, Figure 2 is an explanatory diagram of dog bones when edge rolling is performed using flat rolls, and Figure 3 is an explanatory diagram when edge rolling is performed using flat rolls. Fig. 4 is a diagram showing the relationship between the width reduction ratio and the dog bone maximum position angle α', and Fig. 5 is a diagram showing the relationship between the width reduction ratio and the dog bone edge width undulation. The ratio Bg/B1 of the distance from Bg to the plate width after rolling B1, the projected contact arc length, and the average plate width B
FIG. 6 is an explanatory diagram of the example stripline, and FIG. 7 is an explanatory diagram of the caliber used in the example. 1...Dogbone, 2...Heating furnace.

Claims (1)

[Scope of Claims] 1. In a hole-type edger for a steel plate, the bottom width of the caliber has a width of 101 to 120% of the thickness of the material, the inclination angle of the caliber is 5°-20°, and a part of the caliber has a width of 101% to 120% of the material thickness, and Edger rolling hole type for steel plate having dimensions such that the depth is in the range of 1.0 to 2.0 times Bg determined by the following formula. However, A, C: Constant Bl: Target strip width after rolling td: Projected contact length Bm: Average strip width Bg Distance from the maximum thickness position of the dot bone shape cross section to the slab edge