WO2020169078A1

WO2020169078A1 - Rolling method for improving surface quality of double-roller continuous casting rolling strip

Info

Publication number: WO2020169078A1
Application number: PCT/CN2020/076119
Authority: WO
Inventors: 刘新院; 李化龙; 刘玉君; 施一新; 刘俭; 马毅; 吴荣洲; 冯庆晓; 史华跃; 郭海荣
Original assignee: 江苏沙钢集团有限公司; 江苏省沙钢钢铁研究院有限公司; 张家港中美超薄带科技有限公司
Priority date: 2019-02-21
Filing date: 2020-02-21
Publication date: 2020-08-27
Also published as: CN109731914B; CN109731914A

Abstract

A rolling method for improving the surface quality of a double-roller continuous casting rolling strip. Two rolling mills (1, 2) are installed on a double-roller continuous casting production line, and the two rolling mills may be independently used or used at the same time; in case of independent use, when one of the rolling mills is used for rolling and a surface problem occurs, the other rolling mill may be used for replacing the rolling mill, and meanwhile, a roller of the fault rolling mill may be replaced on-line; and in case of use at the same time, the rolling strip of the double-roller continuous casting may be rolled to 0.4mm to the thinnest extent. The method solves the problems of frequent casting starts and stops.

Description

Rolling method for improving surface quality of double-roll continuous casting strip

Technical field

The invention relates to a method for improving the surface quality of a double-roll continuous casting strip with a short flow, low cost and thin specifications.

Background technique

The production technology of twin-roll cast-rolling strip steel is a new metallurgical frontier technology with the most development potential in today's steel industry. It is also a short process, low energy consumption, low investment, New technology with low cost and green environment. The feature of the ultra-thin strip production line based on this technology is that liquid molten steel is injected into the molten pool formed by two casting rolls with opposite rotation directions through the flow distribution system to directly produce a casting strip with a thickness of less than 3mm, and then undergo a series of hot rolling to produce the thickness Hot rolled thin strip steel less than 2mm.

At present, the double-roll continuous casting production line has achieved commercial production, which can produce carbon steel, weathering steel, silicon steel and other products. The production line has only one secondary rolling mill, the thinnest rolling thickness is 0.7mm, and the strip surface and edge quality are good .

In actual production, products are prone to quality problems such as roll marks and excessive roughness. Such problems are mainly caused by roll factors. When the first roll of roll printing or roughness exceeds the standard roll, if the production continues, follow-up The rolls are all roll-printed or the roughness exceeds the standard, and the products produced are unqualified products. Therefore, when such problems are encountered in production, they can only be solved by stopping pouring and restarting pouring times. Frequent pouring and pouring are stopped. This severely restricts the casting cost of twin-roll continuous casting.

Aiming at the problems of roll marks and excessive roughness that are easily occurred in double-roll continuous casting straps, the present invention invents a rolling method for solving such surface problems.

Summary of the invention

The invention overcomes the product quality problems related to rolls such as roll marks and excessive roughness on the surface of the existing double-roll continuous casting strip steel. The hot-rolling work rolls can only be replaced after pouring is stopped to ensure product quality. The method is to install two rolling mills on the production line. When there is a problem with the product, you can replace it with another rolling mill for rolling, and replace the roll with the problem, ensuring product quality, increasing the number of continuous casting furnaces, and reducing casting cost.

To achieve the above technical objectives, the present invention adopts the following technical solutions.

A rolling method for improving the surface quality of the twin-roll continuous casting strip. The twin-roll continuous casting production line is equipped with two-pass rolling mills. The specific steps are as follows:

(1) Qualified molten steel is smelted by a converter or an electric furnace, and then passes through a tundish, a transitional package and a counter-rotating copper casting roll to form a casting strip with a certain thickness;

(2) The cast strip is hot-rolled and rolled into a certain thickness of hot-rolled strip;

among them:

a) After the strip undergoes one hot rolling, if the roll marks produced during the rolling process cannot be eliminated, immediately change to another rolling mill for rolling, and replace the roll of the first rolling mill online;

b) The strip undergoes one hot rolling. If the rolling process is smooth and the surface roughness of the product will exceed the standard requirements after continuous casting to a certain number of heats, immediately replace another rolling mill for rolling, and perform rolling on the first rolling mill. Perform online replacement;

(3) After hot rolling, the strip is cooled and coiled into a coil.

Preferably, the molten steel component may be carbon steel, weathering steel, stainless steel, or the like.

Preferably, the molten steel passes through a pair of rotating casting rolls to form a cast strip, the continuous casting speed of which is less than or equal to 100 m/min, and the thickness of the formed cast strip is 1.4-2.2 mm.

Preferably, the two hot rolling mills can be used individually or simultaneously.

Preferably, the cast strip is hot rolled into a 0.7-2.0mm thick hot-rolled steel strip after one pass, and can be rolled into a 0.4-2.0mm thick hot-rolled steel strip after two passes of hot rolling.

Preferably, the strip steel undergoes two passes of hot rolling, and the thinnest strip can be rolled to 0.4 mm strip steel.

Beneficial technical effect

The beneficial technical effects of the present invention are at least:

(1) Realize that the product surface can be rolled by replacing another hot rolling mill due to roll printing problems, thereby ensuring product quality;

(2) Realize that due to roughness problems on the surface of the product, it can be rolled by replacing another hot rolling mill to ensure product quality;

(3) It has realized the stop of pouring caused by the surface quality problems (such as roll print, roughness, etc.) of the product due to roll problems, which has increased the number of continuous pouring furnaces and reduced product costs;

(4) The thinnest double-roll continuous casting production line can be rolled to 0.4mm strip.

Description of the drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but do not limit the present invention.

Figure 1 shows a schematic diagram of the twin rolling mill of the twin roll continuous casting production line.

detailed description

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Unless otherwise defined, the technical terms or scientific terms used in the present disclosure shall be the ordinary meanings understood by those with ordinary skills in the field to which the present invention belongs.

The present invention will be described in detail below.

Example 1

(1) The carbon steel molten steel with qualified composition is smelted by a converter or an electric furnace, and a pair of counter-rotating copper casting rolls form a continuous casting belt with a thickness of 1.8mm and a continuous casting speed of 60m/min;

(2) The cast strip is rolled to 1.5mm after one time of hot rolling, the rolling is not smooth, there is a roll mark, it is replaced with another rolling mill, and the rolling is smooth;

Perform surface inspection on the rolled strip, and there is no roll mark on the surface of the rolled strip.

Example 2

(1) Weather-resistant molten steel with qualified components is smelted in a converter or electric furnace, and a pair of counter-rotating copper casting rolls form a continuous casting belt with a thickness of 2.2mm and a continuous casting speed of 40m/min;

(2) The cast strip is hot-rolled and rolled into a hot-rolled strip with a thickness of 2.0mm, and the fourth furnace is rolled. The surface roughness is close to the lower limit of the judgment standard, and another rolling mill is replaced for rolling;

Perform surface inspection on the rolled strip, and the surface roughness of the rolled strip meets the standard requirements.

Example 3

(1) The molten steel with qualified composition is smelted by the converter or electric furnace, and a pair of counter-rotating copper casting rolls form a continuous casting belt with a thickness of 1.4mm and a continuous casting speed of 90m/min;

(2) The cast strip is rolled into a 0.4mm strip after two passes of hot rolling;

The thickness of the rolled strip is tested, the data meets the requirements, and the plate shape is good.

Example 4

(1) The stainless steel molten steel with qualified composition is smelted by the converter or electric furnace, and a pair of counter-rotating copper casting rolls form a continuous casting belt with a thickness of 1.4mm and a continuous casting speed of 90m/min;

(2) The cast strip is rolled into a 0.7mm strip after one hot rolling;

The foregoing descriptions are merely exemplary embodiments of the present invention, and are not used to limit the protection scope of the present invention, which is determined by the appended claims.

Claims

A method for improving the surface quality of a twin-roll continuous casting strip, which is characterized in that the twin-roll continuous casting production line is equipped with two-pass rolling mills, and the method includes the steps:

(1) Qualified molten steel is smelted by a converter or an electric furnace, and then passes through a tundish, a transitional package and a counter-rotating copper casting roll to form a casting strip with a certain thickness;

(2) The cast strip is hot-rolled and rolled into a certain thickness of hot-rolled strip;

among them:

a) After the strip undergoes a hot rolling, if the roll marks produced during the rolling process cannot be eliminated, immediately change to another rolling mill for rolling, and perform online replacement of the roll of the first rolling mill; and/or

b) The strip undergoes one hot rolling. If the rolling process is smooth and the surface roughness of the product will exceed the standard requirements after continuous casting to a certain number of heats, immediately replace another rolling mill for rolling, and perform rolling on the first rolling mill. Perform online replacement;

(3) After hot rolling, the strip is cooled and coiled into a coil.
The method for improving the surface quality of a twin-roll continuous casting and rolling strip according to claim 1, wherein the composition of the molten steel can be carbon steel, weathering steel or stainless steel.
The method for improving the surface quality of a twin-roll continuous casting and rolling strip according to claim 1 or claim 2, wherein the molten steel passes through a pair of rotating casting rolls to form a cast strip, and the continuous casting speed is less than or equal to 90m/min. The thickness of the cast strip is 1.4-2.2mm.
The method for improving the surface quality of a twin-roll continuous casting strip according to any one of the preceding claims is characterized in that the two hot rolling mills can be used alone or simultaneously.
The method for improving the surface quality of a twin-roll continuous cast-rolled strip according to any one of the preceding claims, characterized in that: the cast strip is hot-rolled one time into a hot-rolled strip with a thickness of 0.7-2.0 mm. Two-pass hot rolling can be rolled into 0.4-2.0mm thick hot rolled strip.
The method for improving the surface quality of the twin-roll continuous casting and rolling strip according to any one of the preceding claims, characterized in that the strip is hot rolled two passes, and the thinnest strip can be rolled to 0.4 mm.