阅读说明：本技术 一种常规轧机生产高压缩比优特钢方法 (Method for producing high-compression-ratio high-quality special steel by conventional rolling mill ) 是由 杨新龙 杨作宏 姜军 金武俊 于 2020-07-09 设计创作，主要内容包括：本发明提供了一种常规轧机生产高压缩比优特钢方法,包括以下步骤,(1)炼钢,(2)连铸、重压下和轻压下,(3)加热,(4)控轧控冷,(5)打包。本发明充分利用了利用连铸坯外冷内热的状态,在铸坯心部的1250-1450℃高温粘塑性区予以轧制变形,实施高温粘塑性区心部组织的粘塑性变形,改善铸坯组织；连铸过程中钢坯自身的热量,无需加热,直接从大规格方坯轧制成常规规格方坯,减少了加热时间、能耗和烧损,同时提高了轧机机时产量,降低的生产成本；在连铸机上添加一组轻压下粗轧机,在高温区域1150-1450℃工作的轧机的轧制力较小,无需投资加热炉,减少了大量的投资。(The invention provides a method for producing high-compression-ratio special steel by a conventional rolling mill, which comprises the following steps of (1) steel making, (2) continuous casting, heavy reduction and light reduction, (3) heating, (4) controlled rolling and controlled cooling, and (5) packaging. The method makes full use of the external cold and internal heat states of the continuous casting billet, performs rolling deformation in the 1250-plus-1450 ℃ high-temperature viscoplasticity area at the core of the casting billet, implements viscoplasticity deformation of the core structure of the high-temperature viscoplasticity area, and improves the casting billet structure; the heat of the steel billet in the continuous casting process is not required to be heated, and the steel billet is directly rolled into a square billet with a conventional specification from a large-specification square billet, so that the heating time, the energy consumption and the burning loss are reduced, the time yield of a rolling mill is improved, and the production cost is reduced; a group of soft reduction rough rolling mills are added on a continuous casting machine, the rolling force of the rolling mill working at the temperature of 1150-.)

1. A method for producing high-compression-ratio special steel by a conventional rolling mill is characterized by comprising the following steps:

(1) making steel to obtain a square billet;

(2) continuously casting the square billet by a continuous casting machine to obtain the following sectional areas: thickness with width =220mm 220 and 180mm square billet, add a heavy reduction equipment and a set of light reduction small-size bundle machine on the conticaster, carry out heavy reduction and light rolling operation, specifically do: controlling the temperature drop of the continuously cast square billet, and pressing the square billet with the thickness of =220mm x 220 and 180mm x 180mm into a high-compression-ratio regular-size square billet with the specification of 150 x 9000 and 12000mm under heavy pressing and light rolling operation at the temperature of 1050 ℃ to 1450 ℃ of a high-temperature viscoplasticity zone;

(3) heating the high compression ratio square billet after entering a furnace;

(4) rolling and cooling the heated square billet with high compression ratio and conventional size to obtain a wire or a bar;

(5) and (4) packaging the wires or rods.

2. The method for producing a high compression ratio special steel by a conventional rolling mill according to claim 1, wherein in the continuous casting operation in the step (2), the mold of the continuous casting machine is in a corner arc transition.

3. The method as claimed in claim 1, wherein the high compression ratio special steel is heated in three stages in the step (3), wherein the preheating stage is 650-.

4. The method for manufacturing high compression ratio special steel by using a conventional rolling mill according to claim 1, wherein in the step (4), the controlled rolling and controlled cooling operation of the wire rod is performed in such a manner that rough rolling and intermediate rolling are performed in a recrystallization zone of a square billet with a conventional size, pre-finish rolling, finish rolling and reduction diameter rolling are performed in a non-recrystallization zone of the square billet with a conventional size, the wire rod is rapidly cooled to a spinning temperature after the rolling is performed, and then the wire rod is cooled to a phase transformation point temperature by using a Tesla roller table.

5. The method for producing high-compression-ratio special steel by using a conventional rolling mill as claimed in claim 1, wherein in the step (4), the controlled rolling and controlled cooling operation of the bar is performed in such a manner that the rough rolling and the intermediate rolling are performed in the recrystallization zone, the pre-finish rolling and the finish rolling are performed in the non-recrystallization zone, the bar is cut in sections after the rolling is performed, and then the bar is cooled to room temperature by a natural cooling method.

6. The method for producing high compression ratio special steel by a conventional rolling mill according to claim 1, wherein in the step (2), when the square billet with the thickness and the width =220mm and 220 is subjected to the light rolling operation, the steps of light reduction, heavy reduction and light reduction flattening are adopted;

pass reduction rate: 1.032-1.093-1.224-1.227-1.181-1.103;

the pass rolling system is as follows:

220*220mm-215*223.8mm-200*220mm-165*218mm-160*183mm-145*171mm-150*150mm。

7. the method for producing high compression ratio special steel by a conventional rolling mill according to claim 1, wherein in the step (2), when the square billet with the thickness and the width =180mm and 180mm is subjected to the light rolling operation, the steps of light reduction, heavy reduction and light reduction flattening are adopted;

pass reduction rate: 1.036-1.085-1.171-1.122;

the pass rolling system is as follows:

180*180mm-175*183mm-165*179mm-143*177mm-150*158mm。

Technical Field

The invention belongs to the technical field of steel rolling, and relates to a method for producing high-compression-ratio high-quality special steel by a conventional rolling mill.

Background

In the current technical background, a part of steel mills with advanced smelting equipment adopt smelting purification and inclusion modification innocent treatment technologies to reduce the defects in finished products, but adopt the technology for steelmaking, have high requirements on the equipment, can not effectively eliminate the segregation of alloy wire rod steel, and a part of steel mills with line rolling modification are used for realizing the increase of compression ratio by increasing the section of a square billet so as to fully press the defects in the raw materials to produce high-quality and ultra-high-quality special steel, meanwhile, large-section special-shaped materials with small compression ratio can be produced, but the realization of the processes needs to be completed by replacing the original rolling line with a large rolling mill and newly building a heating furnace, and the investment is huge.

Disclosure of Invention

The invention aims to provide a method for producing high-compression-ratio special steel by a conventional rolling mill aiming at the problems in the prior art.

Therefore, the invention adopts the following technical scheme:

(1) making steel to obtain a square billet;

(2) continuously casting the square billet by a continuous casting machine to obtain the following sectional areas: thickness with width =220mm 220 and 180mm square billet, add a heavy reduction equipment and a set of light reduction small-size bundle machine on the conticaster, carry out heavy reduction and light rolling operation, specifically do: controlling the temperature drop of the continuously cast square billet, and pressing the square billet with the thickness of =220mm x 220 and 180mm x 180mm into a high-compression-ratio regular-size square billet with the specification of 150 x 9000 and 12000mm under heavy pressing and light rolling operation at the temperature of 1050 ℃ to 1450 ℃ of a high-temperature viscoplasticity zone;

(3) heating the high compression ratio square billet after entering a furnace;

(4) rolling and cooling the heated square billet with high compression ratio and conventional size to obtain a wire or a bar;

(5) and (4) packaging the wires or rods.

Further, in the continuous casting operation in the step (2), the crystallizer of the continuous casting machine is in corner arc transition.

Further, in the step (3), the square billet with the high compression ratio and the conventional size is heated in three stages, wherein the preheating stage is 650-.

Further, in the step (4), in the controlled rolling and controlled cooling operation of the wire rod, rough rolling and medium rolling are completed in a recrystallization area of the square billet with the conventional size, pre-finish rolling, finish rolling and reducing and sizing rolling are completed in a non-recrystallization area of the square billet with the conventional size, after the rolling is completed, the wire rod is rapidly cooled to the spinning temperature, and then the wire rod is cooled to the temperature of the phase transformation point on a Stratemo roller way.

Further, in the step (4), in the controlled rolling and controlled cooling operation of the bar, rough rolling and medium rolling are completed in a recrystallization zone, pre-finish rolling and finish rolling are completed in a non-recrystallization zone, the bar is cut in sections after rolling is completed, then the bar is cooled on a cooling bed, and the bar is cooled to room temperature through a natural cooling mode.

Further, in the step (2), when the light rolling operation is performed on the square billet with the thickness and the width =220mm and 220, the flattening passes are performed under light reduction, heavy reduction and light reduction;

pass reduction rate: 1.032-1.093-1.224-1.227-1.181-1.103;

the pass rolling system is as follows:

220*220mm-215*223.8mm-200*220mm-165*218mm-160*183mm-145*171mm-150*150mm。

further, in the step (2), when the square billet with the thickness and the width =180mm and 180mm is subjected to the light rolling operation, the flattening passes are performed by adopting light reduction, heavy reduction and light reduction;

pass reduction rate: 1.036-1.085-1.171-1.122;

the pass rolling system is as follows:

180*180mm-175*183mm-165*179mm-143*177mm-150*158mm。

the invention has the beneficial effects that:

(1) the conventional rolling mill with small rolling force is used for replacing the original heavy rolling mill with large rolling force to produce the high-quality special steel with high compression ratio, the huge investment of the high-performance high-compression-ratio high-quality special steel on the traditional heavy roughing mill with large rolling force, a matched large heating furnace and large-section steelmaking continuous casting equipment is avoided, only one heavy reduction device and one group of light reduction rolling mills are added on the original continuous casting machine, a square billet with a certain deformation size is obtained through high-temperature rolling, and the square billet is subjected to the conventional high-quality special steel rolling process to obtain the high-quality special steel with high performance, high density and few defects on the original conventional rolling mill.

(2) The method is characterized in that large-section square billets are added among the existing compact type high-quality special steel rolling units, the position of a roughing mill needs to be increased by removing the existing heating furnace, the investment of one heating furnace is about 5000 ten thousand, the investment of the heating furnace of large-size square billets is close to 10000 ten thousand, the added rolling mill is also a heavy-reduction roughing mill, a conventional rolling mill is adopted for producing high-compression-ratio high-quality special steel, only a group of light-reduction roughing mills need to be added on a continuous casting machine, the rolling force of the rolling mill working at the high-temperature region of 1150-.

(3) The technology of producing high-compression-ratio special steel by adopting a conventional rolling mill is adopted, the heat of a steel billet in the continuous casting process is fully utilized, heating is not needed, the steel billet is directly rolled into a square billet with a conventional specification from a large-specification square billet, only the square billet with the conventional specification and size under prepressing is heated to 1200 ℃ in a heating furnace, and compared with the prior art, the heating time, the energy consumption and the burning loss are reduced, the time yield of the rolling mill is improved, and the production cost is reduced.

(4) In the rolling process, the cold and hot states outside and inside the continuous casting billet are utilized to roll and deform in a 1250-plus-1450 ℃ high-temperature viscoplasticity area at the core part of the casting billet, the viscoplasticity deformation of the core part structure of the high-temperature viscoplasticity area is implemented, and the casting billet structure is improved.

Detailed Description

The present invention is explained in detail below with reference to examples.

A method for producing high-compression-ratio special steel by a conventional rolling mill comprises the following steps:

(1) obtaining a square billet through conventional steelmaking operation, selecting high-quality molten iron during steelmaking, smelting the molten iron in a converter, and then feeding the molten iron into a refining furnace, wherein the harmful element S + P is controlled to be less than or equal to 0.020%;

(2) continuously casting a square billet, wherein a continuous casting crystallizer used for continuous casting is in corner arc transition, the sectional area of the continuous casting crystallizer is respectively 220mm x 220mm or 180mm x 180mm, so that the square billet with the specification of 220mm x 220mm and 180mm x 180mm can be obtained after continuous casting, molten steel of a continuous casting process is adopted for protective casting before continuous casting, the casting superheat degree is controlled to be 15-30 ℃, during continuous casting, a group of heavy pressure reduction equipment is used for compressing while compressing to force core inclusions to float upwards, the internal purity of a casting blank is improved, external pulling is simultaneously carried out, a large-size section square billet flowing out from the continuous casting square billet crystallizer in the external pulling process is in a billet pulling speed of 3.5-4.5m/min, the pulled large-size section square billet is in an internal heating and external cooling state, and the internal melting state-external solidification of the billet forms an enough billet shell;

then, a group of soft reduction devices (six rolling mills) are additionally arranged on the continuous casting machine, so that the cost is greatly reduced, heavy reduction operation and then light rolling operation are carried out on the square culture after continuous casting, and the reduction and the cooling water distribution of a reduction device are adjusted according to the target thickness of the square culture and the solidification state of a square billet shell during operation;

specifically, when the light rolling operation is carried out on the square billet with the cross section of 220mm x 220mm, the heat generated in the continuous casting operation is utilized without heating the square billet again, so that the working procedure and energy are saved, namely when the temperature of the square billet is between 1150 ℃ and solidus temperature, the light pressing, heavy pressing and light pressing leveling passes are carried out on the square billet in sequence;

specifically, firstly, soft reduction is adopted, the temperature is highest at the moment, the core part has partial liquid phase, the risk of steel leakage can be generated under high reduction, inclusions can be extruded and floated up under the soft reduction, the length of dendrites is damaged, and the internal quality of the billet is improved. Then, soft reduction is carried out again, the temperature is gradually reduced, the liquid phase of the core part is almost zero, the internal defects of the blank can be effectively pressed, then, heavy reduction is carried out twice, the rolling force can be effectively ensured to gradually permeate into the casting blank under heavy reduction, the pressing, loosening, hollowing and other defects are improved to the maximum extent, the internal quality is greatly improved, and finally, the pass is flattened under light reduction;

pass reduction rate: 1.032-1.093-1.224-1.227-1.181-1.103,

the pass rolling system is as follows:

220mm-215 mm-223.8 mm-200 mm-220 mm-165 mm-218 mm-160 mm-183 mm-145 mm-171 mm-150 mm (shown in table 1);

table 1220 mm high-performance pre-pressing blank pressing system

After the above pressing operation is completed, square billets of 150 × 150mm0 × 9000 and 12000mm can be obtained;

when the square billet with the section of 180mm x 180mm is subjected to soft reduction operation, soft reduction, heavy reduction and finally soft reduction flattening pass are adopted;

specifically, firstly, soft reduction is adopted, the temperature is highest at the moment, a part of liquid phase exists in a core part, the risk of steel leakage can be generated under the condition of large reduction, inclusions can be extruded and floated up under the condition of soft reduction, the length of dendritic crystals is damaged, the internal quality of billets is improved, then, heavy reduction is adopted, the rolling force can be effectively ensured to gradually permeate into the casting billets under the condition of heavy reduction, the defects such as pressing, loosening, hollowing and the like are improved to the maximum extent, the internal quality is greatly improved, and finally, the pass of leveling is carried out under;

pass reduction rate: 1.036-1.085-1.171-1.122;

the pass rolling system is as follows:

180 x 180mm-175 x 183mm-165 x 179mm-143 x 177mm-150 x 158mm (as shown in table 2);

table 2180 mm high-performance pre-pressing blank pressing system

After the whole operation is finished, a high-performance high-compression-ratio square billet with the specification of 160 x 160mm x 9000-12000mm is finally obtained;

(3) heating the square billet with the conventional size and the high compression ratio, specifically putting the square billet with the conventional size and the high compression ratio into a heating furnace, and carrying out three-stage heating, wherein the preheating section is 650-;

(4) rolling and cooling the heated square billet with high compression ratio and conventional size to prepare a wire or a bar;

in the controlled rolling and controlled cooling manufacturing process of the wire rod:

firstly, a square billet with high compression ratio and conventional size is subjected to bundling and intermediate rolling by a rolling mill, the rough rolling and the intermediate rolling are finished in a recrystallization zone of the square billet, after the rough rolling and the intermediate rolling are finished, the pre-finish rolling, the finish rolling and the reduction sizing rolling are finished in a non-recrystallization zone, after the rolling is finished, the wire rod is quickly cooled to the spinning temperature, then the wire rod is cooled to the phase transformation point temperature by a Stratemo roller way to form the wire rod, and then the wire rod is collected, packed, hung and packaged and put in storage.

In the controlled rolling and controlled cooling manufacturing process of the bar:

and finishing rough rolling and medium rolling in a recrystallization area, finishing pre-finish rolling and finish rolling in a non-recrystallization area, cutting the bar in sections after rolling, cooling the bar on a cooling bed, naturally cooling the bar to room temperature, bundling and hanging the bar, and packaging and warehousing the bar.