JPS63295003A - Method for warm rolling brittle steel strip - Google Patents

Abstract

PURPOSE:To prevent breakdown of a brittle steel strip by heating both side parts of a roll body during rolling and rolling a steel strip with heat crowns of rolling rolls controlled. CONSTITUTION:Heating burners 3 are installed in both side parts of the contacting part between rolling rolls 1a, 1b and a steel strip S. During rolling the strip S, a temp. in the longitudinal direction of the roll body is measured by a thermometer 5 installed on the roll 1a to control heating of the burners 3. The burners 3 have plural burner nozzles and a heating width on the both side parts of the rolls 1a, 1b is adjusted. Thus, stresses in edge parts of the brittle steel strip S are reduced and breakdowns are prevented because heat crowns of the rolls 1a, 1b are held in the optimal condition.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for warm rolling a brittle steel strip.

[Conventional technology and its problems]

Although brittle materials such as high Sc steel are known to be difficult to process by rolling, these materials can also be rolled by increasing the processing temperature.

In such rolling at elevated processing temperatures, the strip temperature becomes higher than the roll temperature, so the plate road portion of the roll is heated by the strip and undergoes repeated thermal expansion, resulting in the roll forming a large convex crown. FIG. 5 shows the amount of heat crown. Due to such rounding, the roll shape becomes a pan eave-like shape that changes abruptly at the ends of the width of the sheet, so that the rolled strip has an extreme center elongation, and the ends of the sheet are subjected to large tensile stress. and,
Strips of brittle material easily break when subjected to such plate edge tensile stresses.

Conventionally, a method for suppressing heat crown is to cool the roll using a coolant, but this method cannot be applied to brittle materials because the strip temperature cannot be lowered due to workability problems.

The present invention was made in view of these problems, and it is an object of the present invention to provide a method that can suppress the heat crown of a rolling roll and warm-roll a brittle steel strip without causing breakage.

[Means to solve the problem]

For this reason, the present invention heats both sides of the roll body including the vicinity of the steel strip edge contact portion in the longitudinal direction of the roll body during rolling, thereby controlling the heat crown of the roll while rolling. be.

By controlling the heat crown in this manner, the thermal expansion of the plate road portion of the rolling roll is made uniform, and the center elongation of the copper strip can be appropriately prevented.

Heating on both sides of the roll body, including near the steel strip edge contact area,
This can be performed by direct heating using a burner or other heating means, or indirect heating via a backup roll or the like.

1 and 2 show one implementation situation of the present invention,
The rolling roll is directly heated with a heating burner.

In Figure 1, (1m) (lb) is the upper and lower rolling rolls, (2) is the backup roll, (3) is the heating burner, (4) is the stand, and (5) is the temperature for measuring the roll temperature. Meter (contact type), (8) is a copper band.

The heating burner (3) is arranged opposite to each of the rolling rolls (1a) and (1b) so as to heat both side portions of the roll body of the rolling roll. This heating burner has a plurality of burner parts (burner nozzles) along the longitudinal direction of the roll body,
The width of the flame on both sides of the roll body can be adjusted as appropriate.

In such equipment, during rolling of the copper strip (S), the copper strip (S) is rolled.
Both side portions of the roll body including the vicinity of the plate end contact portion S) are directly heated by the heating burner (3), and the heat crown control is performed.

In reality, the temperature in the longitudinal direction of the roll body is measured by a thermometer (5), and the heating width and the like are adjusted by controlling on/off of each burner part constituting the heating burner.

Figure 3 shows the influence of the heating width on the amount of heat crown in warm rolling using the equipment shown in Figure 1.Heating width 4 makes it possible to control the crown, especially as the rolling time progresses. It can be seen that ΔH can be appropriately suppressed by gradually widening the heating width.

〔Example〕

Using equipment similar to that shown in Figs. 1 and 2, the steel strip is heated while heating the roll portion of a certain width from the end contact position of the rolled steel strip to the roll end direction l. Rolling was carried out. For comparison, warm rolling was performed under similar conditions without roll heating. The specific rolling conditions are as follows.

Copper strip: 6.5% different steel copper strip heating temperature -
: 350°C Roll diameter: 200°C Roll length: 500 days Copper band width: 200mm Roll heating conditions (invention) Heating @ = 30cm Heating temperature: 1000°C Figure 4 shows the above example of the invention and In the comparative example, the change in the amount of heat crown ΔH (see Figure 3) during rolling is shown over time. In the comparative example where roll heating is not performed, a large heat crown occurs as rolling progresses, whereas in the comparative example, a large heat crown occurs as rolling progresses, whereas in the comparative example where roll heating is not performed, a large heat crown occurs as rolling progresses. In the example, the amount of heat crown is kept small. In the present invention, the copper strip could be rolled from a thickness of 2.0+m to 0.5-m without breaking, whereas in the comparative example, the copper strip had a large center elongation and eventually broke.

〔Effect of the invention〕

According to the present invention described above, heat crown of the rolling roll can be suppressed and brittle steel strips such as high 81 copper strips can be warm rolled without being broken.

[Brief explanation of the drawing]

1 and 2 show one implementation situation of the present invention,
FIG. 1 is a side view, and FIG. 2 is a view taken along line nn in FIG. 1. FIG. 3 shows the influence of the heating width of both sides of the roll body on the amount of heat crown during warm rolling. FIG. 4 shows changes over time in the amount of heat crown of the inventive example and the comparative example in Example 1. FIG. 5 shows the amount of heat crown in the longitudinal direction of the roll body during warm rolling of a steel strip.

Claims (1)

[Claims] During rolling, in the longitudinal direction of the rolling rolls, Both sides of the roll body including the vicinity of the steel strip edge contact area Heat the side part and heat the rolling roll. Brittle steel strip characterized by controlling warm rolling method.