Production method of large-section rectangular blank industrial pure iron

Abstract

The invention belongs to the technical field of industrial pure iron square steel preparation, and discloses a production method of large-section rectangular blank industrial pure iron. The production method comprises the steps that an uncut continuous casting rectangular billet is conveyed to a heating furnace to be heated, and a heated continuous casting rectangular billet is obtained; and the heated continuous casting rectangular billet is rolled at the temperature of a ferrite phase region, and the industrial pure iron square steel is obtained. According to the method, the problem of corner cracks in the rolling process can be avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial pure iron square steel preparation, and more specifically, relates to a production method of large-section square billet industrial pure iron. Background Art

[0002] With the continuous advancement of industrial manufacturing technology, the requirements for material properties are increasing. Industrial pure iron square steel has broad application prospects in electronics, aerospace, precision instruments and other fields due to its excellent magnetic, electrical conductivity and mechanical properties. However, the heating and rolling processes in its production process directly affect the quality of the final product. For example, corner cracks in industrial pure iron square steel have always been a common problem in industrial pure iron production. Specifically: In the prior art, industrial pure iron square steel is generally produced by continuous casting slabs, which are cut into several rectangular billets along the length direction, and the cut rectangular billets are transported to the heating furnace for heating. The temperature of the soaking section is 1200-1280℃, and after soaking for a certain period of time, rolling is carried out to obtain the desired cross-section product; however, during the high-temperature rolling process, crack defects are very likely to occur at the corners of the ingot; the main reason is that after the ingot is heated and enters the rolling mill deformation process, the temperature drop at the corners is greater than that at other parts, and different phase regions appear at the corners and other parts, and the organization is uneven. There are significant differences in its thermoplasticity, and the ability to resist deformation during rolling is also different.

[0003] Therefore, it is urgent to propose a new production method for large-section rectangular billet industrial pure iron to optimize product performance and improve production efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a method for producing large-section rectangular billet industrial pure iron in view of the shortcomings of the prior art. The method of the present invention can avoid the problem of corner cracks during the rolling process.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a method for producing large-section square billets of industrial pure iron, the production method comprising: conveying uncut continuous casting square billets to a heating furnace for heating to obtain heated continuous casting square billets; rolling the heated continuous casting square billets at a ferrite phase temperature to obtain industrial pure iron square steel.

[0006] According to the present invention, preferably, the cross-sectional dimensions of the uncut continuous casting square billet are (380-400) mm×(500-520) mm. Further preferably, the specifications of the uncut continuous casting square billet are 390 mm×510 mm×5810 mm.

[0007] In the present invention, the method for preparing the uncut continuous casting square billet adopts a method known to those skilled in the art. As a preferred embodiment, the process flow of the method for preparing the uncut continuous casting square billet is KR method desulfurization pretreatment → converter smelting → LF refining furnace → RH vacuum refining furnace → continuous casting.

[0008] According to the present invention, preferably, the heating furnace comprises a heating section 1, a heating section 2 and a soaking section, and optionally, a heating section 3 is further provided between the heating section 2 and the soaking section.

[0009] According to the present invention, preferably, the temperature of the heating stage 1 is 650-750°C.

[0010] The temperature of the heating section 2 is 870-970°C;

[0011] The temperature of the heating section 3 is 1000-1060°C;

[0012] The temperature of the soaking section is 930-1000°C.

[0013] According to the present invention, preferably, the heating time of the heating furnace is >600 min.

[0014] According to the present invention, preferably, the rolling includes reversible rolling and four-stand short stress rolling in sequence.

[0015] According to the present invention, preferably, the reversible rolling mill performs 11 rolling passes, preferably 11 rolling passes.

[0016] According to the present invention, preferably, the total number of rolling passes of the four short stress rolling mills is 4-8 passes, preferably 4 passes.

[0017] According to the present invention, preferably, the rolling temperature of each pass is <900°C;

[0018] According to the present invention, preferably, the cross-sectional dimensions of the industrial pure iron square steel are (145-155) mm×(145-155) mm. Further preferably, the cross-sectional dimensions of the industrial pure iron square steel are 150 mm×150 mm.

[0019] The beneficial effects of the technical solution of the present invention are as follows:

[0020] The method of the invention is a heating and rolling production method for industrial pure iron square steel, which can avoid the problem of corner cracks occurring during the rolling process.

[0021] The present invention reasonably controls the heating temperature and the rolling temperature of each pass, performs rolling in a single-phase ferrite phase region, avoids passing through a two-phase region during the rolling process, and further avoids the problem of uneven structure and stress concentration during the phase change process, which ultimately avoids the occurrence of crack defects in the corners.

[0022] The present invention rolling in the ferrite phase region helps to control the texture development of the material, which is very important for certain applications, such as requiring good stamping performance or specific anisotropy.

[0023] Compared with the austenite phase region, the rolling performed in the ferrite phase region of the present invention can reduce the work hardening effect. This is because the plastic deformation of ferrite is easier, and the recrystallization of grains during the deformation process is more rapid, which reduces the accumulation of residual stress.

[0024] The present invention can simplify the production process by rolling in the ferrite phase region, because high temperature treatment is not required, thereby reducing energy consumption.

[0025] The present invention rolls in the ferrite phase region to help refine the grains. At lower temperatures, the deformation of ferrite can promote grain refinement because the deformation promotes dynamic or static recrystallization processes, thereby forming finer grains. Fine grains can significantly improve the strength and toughness of the material.

[0026] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

[0028] Figure 1 The cross-sectional view of industrial pure iron square steel obtained by a method for producing large-section rectangular billet industrial pure iron provided in Example 1 of the present invention is shown.

[0029] Figure 2 The cross-sectional view of industrial pure iron square steel obtained by a method for producing large-section rectangular billet industrial pure iron provided in Example 2 of the present invention is shown.

[0030] Figure 3 The cross-sectional view of industrial pure iron square steel obtained by a method for producing industrial pure iron with large cross-section rectangular billets provided in Example 3 of the present invention is shown.

[0031] Figure 4 The cross-sectional view of industrial pure iron square steel obtained by a method for producing large-section rectangular billet industrial pure iron provided in Example 4 of the present invention is shown. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0033] Example 1

[0034] This embodiment provides a method for producing large-section rectangular billet industrial pure iron, the production method comprising:

[0035] The uncut continuous casting rectangular billet is obtained through the process of KR method desulfurization pretreatment → converter smelting → LF refining furnace → RH vacuum refining furnace → continuous casting, with a cross-sectional size of 390mm×510mm;

[0036] The uncut continuous casting billet is transported to a heating furnace for heating to obtain a heated continuous casting billet; wherein the heating furnace has a heating section 1 temperature of 690-700°C, a heating section 2 temperature of 890-905°C, a heating section 3 temperature of 1010-1020°C, a soaking section temperature of 950-960°C, a soaking time of 205 minutes, and a total heating time of 605 minutes;

[0037] The heated continuous casting square billet is rolled at the ferrite phase temperature to obtain industrial pure iron square steel. During the rolling, the high-pressure water descaling is turned on, the rolling mill is not supplied with water, the starting rolling temperature is 905°C, the final rolling temperature is 850°C, and the rolling includes reversible rolling (11 passes) and 4 short stress rolling (4 passes) performed in sequence.

[0038] The cross-sectional size of the industrial pure iron square steel is 150mm×150mm, and no corner cracks occur, but central cracks occur. The central cracks are caused by insufficient total heating time, low core temperature of the continuous casting billet, and uneven deformation during the rolling process.

[0039] Example 2

[0040] This embodiment provides a method for producing large-section rectangular billet industrial pure iron, the production method comprising:

[0041] The uncut continuous casting rectangular billet is obtained through the process of KR method desulfurization pretreatment → converter smelting → LF refining furnace → RH vacuum refining furnace → continuous casting, with a cross-sectional size of 390mm×510mm;

[0042] The uncut continuous casting billet is transported to a heating furnace for heating to obtain a heated continuous casting billet; wherein the heating furnace has a heating section 1 temperature of 690-700°C, a heating section 2 temperature of 890-905°C, a heating section 3 temperature of 1010-1020°C, a soaking section temperature of 950-960°C, a soaking time of 235 minutes, and a total heating time of 635 minutes;

[0043] The heated continuous casting square billet is rolled at the ferrite phase temperature to obtain industrial pure iron square steel. During the rolling, high-pressure water descaling is turned on, the rolling mill is supplied with water, the starting rolling temperature is 895°C, and the final rolling temperature is 830°C. The rolling includes reversible rolling (11 passes) and 4 short stress rolling (4 passes) performed in sequence.

[0044] The cross-sectional size of the industrial pure iron square steel is 150 mm×150 mm, no corner cracks occur, and there are a small amount of center cracks.

[0045] Example 3

[0046] This embodiment provides a method for producing large-section rectangular billet industrial pure iron, the production method comprising:

[0047] The uncut continuous casting rectangular billet is obtained through the process of KR method desulfurization pretreatment → converter smelting → LF refining furnace → RH vacuum refining furnace → continuous casting, with a cross-sectional size of 390mm×510mm;

[0048] The uncut continuous casting billet is transported to a heating furnace for heating to obtain a heated continuous casting billet; wherein the heating furnace has a heating section 1 temperature of 710-720°C, a heating section 2 temperature of 890-905°C, a heating section 3 temperature of 1020-1030°C, a soaking section temperature of 940-950°C, a soaking time of 260 minutes, and a total heating time of 705 minutes;

[0049] The heated continuous casting square billet is rolled at the ferrite phase temperature to obtain industrial pure iron square steel. During the rolling, high-pressure water descaling is turned on, the rolling mill is water-fed, the starting rolling temperature is 900°C, and the final rolling temperature is 810°C. The rolling includes reversible rolling (11 passes) and 4 short stress rolling mills (4 passes) performed in sequence.

[0050] The cross-sectional size of the industrial pure iron square steel is 150 mm×150 mm, and no corner cracks or micro-center cracks occur.

[0051] Example 4

[0052] This embodiment provides a method for producing large-section rectangular billet industrial pure iron, the production method comprising:

[0053] The uncut continuous casting rectangular billet is obtained through the process of KR method desulfurization pretreatment → converter smelting → LF refining furnace → RH vacuum refining furnace → continuous casting, with a cross-sectional size of 390mm×510mm;

[0054] The uncut continuous casting billet is transported to a heating furnace for heating to obtain a heated continuous casting billet; wherein the temperature of the heating furnace for heating section 1 is 710-720°C, the temperature of the heating section 2 is 890-905°C, the temperature of the heating section 3 is 1020-1030°C, the temperature of the soaking section is 940-950°C, the soaking time is 290 minutes, and the total heating time is 735 minutes;

[0055] The heated continuous casting square billet is rolled at the ferrite phase temperature to obtain industrial pure iron square steel. During the rolling, high-pressure water descaling is turned on, the rolling mill is supplied with water, the starting rolling temperature is 895°C, and the final rolling temperature is 810°C. The rolling includes reversible rolling (11 passes) and 4 short stress rolling (4 passes) performed in sequence.

[0056] The cross-sectional size of the industrial pure iron square steel is 150 mm×150 mm, and no corner cracks or center cracks are generated.

[0057] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for producing large-section rectangular billet industrial pure iron, characterized in that: The production method comprises: conveying uncut continuous casting square billets to a heating furnace for heating to obtain heated continuous casting square billets; and rolling the heated continuous casting square billets at a ferrite phase temperature to obtain industrial pure iron square steel.

2. The method for producing large-section rectangular billet industrial pure iron according to claim 1, wherein: The cross-sectional dimensions of the uncut continuous casting square billet are (380-400) mm×(500-520) mm.

3. The method for producing large-section rectangular billet industrial pure iron according to claim 1, wherein: The heating furnace comprises a heating section 1, a heating section 2 and a soaking section. Optionally, a heating section 3 is further provided between the heating section 2 and the soaking section.

4. The method for producing large-section rectangular billet industrial pure iron according to claim 3, wherein: The temperature of the heating section 1 is 650-750°C; The temperature of the heating section 2 is 870-970°C; The temperature of the heating section 3 is 1000-1060°C; The temperature of the soaking section is 930-1000°C.

5. The method for producing large-section rectangular billet industrial pure iron according to claim 1, wherein: The heating time of the heating furnace is >600 min.

6. The method for producing large-section rectangular billet industrial pure iron according to claim 1, wherein: The rolling includes reversible rolling and four-stand short stress rolling in sequence.

7. The method for producing large-section rectangular billet industrial pure iron according to claim 6, wherein: The reversible rolling mill performs 11 rolling passes.

8. The method for producing large-section rectangular billet industrial pure iron according to claim 6, wherein: The total number of rolling passes of the four short stress rolling mills is 4-8.

9. The method for producing large-section rectangular billet industrial pure iron according to claim 6, wherein: The rolling temperature of each pass is less than 900°C.

10. The method for producing large-section rectangular billet industrial pure iron according to any one of claims 1 to 9, wherein: The cross-sectional dimensions of the industrial pure iron square steel are (145-155) mm×(145-155) mm.

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