High-aluminum peritectic steel with aluminum content ≥ 0.45% continuous casting method

Abstract

The application discloses a high-aluminum peritectic steel with aluminum content greater than or equal to 0.45% and a continuous casting method of the high-aluminum peritectic steel. The chemical components of the high-aluminum peritectic steel with aluminum content greater than or equal to 0.45% are as follows in percentage by mass: C is 0.135-0.155%, Si is 1.10-1.30%, Mn is 1.70-1.90%, P is less than or equal to 0.015%, S is less than or equal to 0.006%, Al is 0.45-0.55%, Ti is 0.010-0.025%, and the balance is iron and inevitable impurities. The high-aluminum peritectic steel is continuously cast by using a straight-arc caster. The cooling is carried out by using a weak cooling mode. A non-sine hydraulic vibration mode is used. The roller electromagnetic stirring is used in the continuous casting process. By developing a protective slag for the high-aluminum peritectic steel, the contradiction between the requirements of the peritectic steel and the high-aluminum steel for the protective slag is solved, the continuous casting of the high-aluminum peritectic steel is realized, and the production efficiency is greatly improved. By optimizing the electromagnetic stirring mode and parameters, the layered cracking of the finished steel plate caused by composition segregation is solved, the problems of large liquid surface fluctuation of a crystallizer, lateral depression and longitudinal cracking of a casting blank in the high-aluminum peritectic steel casting process are solved, and the continuous casting production is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metallurgy, and particularly relates to a continuous casting method of high-aluminum peritectic steel with aluminum content greater than or equal to 0.45%. BACKGROUND

[0002] Lightweight and long service life of engineering machinery are the development direction of the industry, and to meet this trend, the raw materials need to be continuously upgraded.

[0003] The traditional production process has the disadvantages of high cost and long production cycle. Therefore, a 1000 MPa grade or above dual-phase ultra-high strength steel is developed as an upgraded product for concrete mixer tank body and blade. The steel introduces Si and Al elements to narrow the austenite zone and promote the formation of ferrite, forming a new C-Mn-Si-Al composition system. Since this type of steel is in the peritectic steel category, the mold liquid level fluctuates greatly during continuous casting, and the billet is prone to crack defects. The steel contains a high content of Al, which increases the reactivity of the molten steel and the protective slag, resulting in deterioration of the performance of the protective slag during casting, and continuous casting cannot be achieved. The high Al steel has conflicting requirements for the performance of the protective slag compared to peritectic steel, and it is currently difficult to achieve continuous casting of high-aluminum peritectic steel, making continuous casting difficult. SUMMARY

[0004] To solve some or all of the technical problems existing in the prior art, the present application provides a continuous casting method of high-aluminum peritectic steel with aluminum content greater than or equal to 0.45%.

[0005] The continuous casting method of high-aluminum peritectic steel with aluminum content greater than or equal to 0.45% according to the present application comprises the following processes:

[0006] Preparation: The chemical composition of the high-aluminum peritectic steel with aluminum content greater than or equal to 0.45% is as follows in terms of mass percentage: C is 0.135-0.155%, Si is 1.10-1.30%, Mn is 1.70-1.90%, P is less than or equal to 0.015%, S is less than or equal to 0.006%, Al is 0.45-0.55%, Ti is 0.010-0.025%, and the balance is iron and unavoidable impurities.

[0007] Casting: The high-aluminum peritectic steel is continuously cast using a straight-arc caster;

[0008] Cooling: Cooling is performed using a weak cooling method;

[0009] Vibration: A non-sine hydraulic vibration mode is used;

[0010] Electromagnetic stirring: Roller-type electromagnetic stirring is used during continuous casting;

[0011] A special protective slag is used.

[0012] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, during the casting process, the casting machine parameters used are:

[0013]

[0014]

[0015] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, when producing a 230mm-thick casting blank, the pulling speed is controlled at 0.85-1.05m / min, with a target of 0.90m / min.

[0016] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, during the cooling process, in the first cooling, weak cooling is used, with the wide surface cooling water quantity set at 4000L / min and the narrow surface cooling water quantity set at 550L / min;

[0017] In the second cooling, the specific water quantity is controlled between 0.64-0.71L / kg steel.

[0018] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, during the vibration process, the negative stripping time is < 0.11s.

[0019] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, during the electromagnetic stirring process, the stirring current is 400A and the frequency is 5HZ.

[0020] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, during the use of the protective slag, the chemical and physical indexes of the protective slag are:

[0021] Chemical indexes

[0022]

[0023] Physical indexes

[0024] Viscosity at 1300°C (Pa.s) Melting point (°C) Moisture (%) 0.10±0.05 1160±30 ≤0.5

[0025] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, it also includes ladle fork arm setting, with the time set at ≥ 8min.

[0026] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%,

[0027] The tundish superheat is controlled at 25-35℃;

[0028] The tundish nozzle insertion depth control requirement is 125±5mm.

[0029] The high-aluminum peritectic steel continuous casting method with aluminum content ≥0.45% of the present application has the following advantages and beneficial effects:

[0030] (1) The high-aluminum peritectic steel continuous casting process suitable for aluminum content ≥0.45% is adopted, and by reasonably setting the tundish superheat, continuous casting cooling system, tundish downhole insertion depth, and continuous casting pouring speed and other process parameters, the problems of large crystallizer liquid level fluctuation, casting surface transverse depression and longitudinal cracking during the pouring process are solved, and continuous casting production is realized.

[0031] (2) The developed high-aluminum peritectic steel protective slag is adopted, which solves the contradiction between the requirements of peritectic steel and high-aluminum steel for protective slag, reduces the crystallizer friction, realizes the continuous casting of high-aluminum peritectic steel, and increases the continuous casting furnace number from the initial 1-2 furnaces to 8 furnaces, greatly improving the production efficiency.

[0032] (3) By optimizing the electromagnetic stirring mode and parameters, the problem of layered cracking of finished steel plate caused by composition segregation is solved. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely in combination with specific embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0034] The high-aluminum peritectic steel continuous casting method with aluminum content ≥0.45% of the present application includes the following processes:

[0035] Preparation: The chemical composition of the high-aluminum peritectic steel with aluminum content ≥0.45% is as follows in terms of mass percentage: C is 0.135-0.155%, Si is 1.10-1.30%, Mn is 1.70-1.90%, P ≤0.015%, S ≤0.006%, Al is 0.45-0.55%, Ti is 0.010-0.025%, and the balance is iron and unavoidable impurities;

[0036] Casting: The high-aluminum peritectic steel is continuously cast by using a straight-arc casting machine;

[0037] Cooling: The cooling is performed by using a weak cooling mode;

[0038] Vibration: A non-sine hydraulic vibration mode is adopted;

[0039] Electromagnetic stirring: The roller-type electromagnetic stirring is used during the continuous casting process;

[0040] A special protective slag is used.

[0041] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, the casting machine parameters used during the casting process are as follows:

[0042]

[0043]

[0044] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, when producing a 230mm-thick casting blank, the pulling speed is controlled at 0.85-1.05m / min, with a target of 0.90m / min.

[0045] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, during the cooling process, in the first cooling, weak cooling is adopted, with the wide surface cooling water quantity set at 4000L / min and the narrow surface cooling water quantity set at 550L / min;

[0046] In the second cooling, the specific water quantity is controlled between 0.64-0.71L / kg steel.

[0047] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, during the vibration process, the negative stripping time is < 0.11s.

[0048] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, during the electromagnetic stirring process, the stirring current is 400A and the frequency is 5HZ, thereby effectively solving the problem of product steel plate separation cracking caused by composition segregation.

[0049] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, during the use of the protective slag, the chemical and physical indexes of the protective slag are as follows:

[0050] Chemical indexes

[0051]

[0052] Physical indexes

[0053] Viscosity at 1300°C (Pa.s) Melting point (°C) Moisture (%) 0.10±0.05 1160±30 ≤0.5

[0054] The contradiction between the requirements of peritectic steel and high-AL steel for the protective slag is solved, the mold friction is reduced, the continuous casting of high-aluminum peritectic steel is realized, the continuous casting furnace number is increased from the initial 1-2 furnaces to 8 furnaces, and the production efficiency is greatly improved.

[0055] Further, in the above-mentioned continuous casting method of high-aluminum peritectic steel with aluminum content ≥ 0.45%, it also includes ladle fork arm setting, with the time set at ≥ 8min.

[0056] Further, in the high-aluminum peritectic steel continuous casting method with the aluminum content ≥ 0.45%,

[0057] The superheat of the tundish is controlled at 25-35°C;

[0058] The tundish nozzle insertion depth control requirement is 125±5mm, the high-aluminum peritectic steel continuous casting process with the aluminum content ≥ 0.45% is adopted, the process parameters such as the tundish superheat, the continuous casting cooling system, the tundish nozzle insertion depth and the continuous casting pouring speed are reasonably set, the problems of large crystallizer liquid level fluctuation, slab surface transverse depression and longitudinal crack in the pouring process are solved, and the continuous casting production is realized.

[0059] Example one:

[0060] The straight arc caster is used to produce the high-aluminum peritectic steel, the pouring section thickness is 230mm, and the pouring section width is 1640mm;

[0061] The raw material is the high-aluminum peritectic steel with the aluminum content ≥ 0.45%, and the chemical composition of the high-aluminum peritectic steel is as follows in terms of mass percentage: C is 0.143%, Si is 1.18%, Mn is 1.76%, P is 0.0079%, S is 0.0013%, Al is 0.539%, Ti is 0.0215%, and the balance is iron and inevitable impurities;

[0062] The ladle arm is used for static, and the time is 10min;

[0063] The tundish superheat is controlled at 31-34°C;

[0064] The pulling speed is controlled at 0.9m / min;

[0065] Cooling:

[0066] The wide face cooling water amount of the first cooling is 4000L / min, and the narrow face cooling water amount is 550L / min;

[0067] The secondary cooling specific water amount is 068L / kg; under the 090m / min pulling speed, the secondary cooling water configuration is as follows:

[0068] Z1 N Z1 IO Z2 IOC Z2 IOM Z3 IOC Z3 IOM Z4 IOC Z4 IOM 100 198 155 160 164 169 132 136 Z5 IOC Z5 IOM Z6 IC Z6 IM Z6 OC Z6 OM Z7 IC Z7 IM 100 144 60 87 90 130 35 50 Z7 OC Z7 OM Z8 IC Z8 IM Z8 OC Z8 OM Z9 I 59 86 30 58 59 86 80

[0069] Vibration: the amplitude is 5.9mm, the vibration frequency is 151cpm, and the negative slip time is 0.104s under the 0.9m / min pulling speed;

[0070] Electromagnetic stirring: the roller type electromagnetic stirring is used, the stirring current is 400A, and the frequency is 5Hz;

[0071] Physical and chemical indexes of the protective slag:

[0072]

[0073] The insertion depth of the tundish nozzle is 128mm.

[0074] Example two:

[0075] The high-aluminum peritectic steel with aluminum content of more than or equal to 0.45% is produced by using a straight arc continuous casting machine, the pouring section thickness is 230mm, and the pouring section width is 1530mm.

[0076] Preparation: the chemical composition of the high-aluminum peritectic steel with aluminum content of more than or equal to 0.45% is as follows in percentage by mass: C is 0.148%, Si is 1.18%, Mn is 1.79%, P is 0.0067%, S is 0.001%, Al is 0.45%, Ti is 0.0195%, and the balance is iron and inevitable impurities;

[0077] The ladle arm is used for staticizing, and the time is 18min;

[0078] The tundish superheat is controlled to be 27-35 DEG C;

[0079] The drawing speed is controlled to be 0.9m / min;

[0080] Cooling:

[0081] The wide face cooling water amount of the first cooling is 4000L / min, and the narrow face cooling water amount is 550L / min;

[0082] The secondary cooling specific water amount is 0.66L / kg; under the drawing speed of 0.90m / min, the secondary cooling water configuration is as follows:

[0083] Z1 N Z1 IO Z2 IOC Z2 IOM Z3 IOC Z3 IOM Z4 IOC Z4 IOM 100 198 155 154 164 163 132 131 Z5 IOC Z5 IOM Z6 IC Z6 IM Z6 OC Z6 OM Z7 IC Z7 IM 100 136 60 82 90 80 35 48 Z7 OC Z7 OM Z8 IC Z8 IM Z8 OC Z8 OM Z9 I 59 81 30 58 59 81 80

[0084] Vibration: the amplitude is 5.9mm, the vibration frequency is 151cpm, and the negative slip time is 0.104s under the drawing speed of 0.9m / min;

[0085] Electromagnetic stirring, the roller type electromagnetic stirring is used in the continuous casting process, the stirring current is 400A, and the frequency is 5Hz;

[0086] Physical and chemical indexes of the protective slag:

[0087]

[0088] The insertion depth of the tundish nozzle is 125mm.

[0089] Compared with the prior art, the high-aluminum peritectic steel continuous casting method with aluminum content of more than or equal to 0.45% has the following advantages and beneficial effects:

[0090] (1) A high-aluminum peritectic steel continuous casting process suitable for aluminum content ≥0.45% was adopted. By reasonably setting process parameters such as tundish superheat, continuous casting cooling regime, tundish bottom nozzle insertion depth, and continuous casting pouring speed, the problems of large fluctuations in the liquid level of the crystallizer, transverse depressions and longitudinal cracks on the surface of the billet were solved, and continuous casting production was realized.

[0091] (2) The development of protective slag for high-alumina peritectic steel has solved the contradiction between the protective slag requirements of peritectic steel and high-AL steel, reduced the friction of the crystallizer, and enabled continuous casting of high-alumina peritectic steel. The number of continuous casting furnaces has been increased from the initial 1-2 furnaces to 8 furnaces, which has greatly improved production efficiency.

[0092] (3) By optimizing the electromagnetic stirring method and parameters, the problem of delamination and cracking of finished steel plates caused by component segregation was solved.

[0093] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. At the same time, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A continuous casting method of a high-aluminum peritectic steel having an aluminum content of > 0.45%, characterized in that, The high-aluminum peritectic steel with aluminum content of greater than or equal to 0.45% is continuously cast by a method comprising the following steps: Preparation: the chemical composition of the high-aluminum peritectic steel with aluminum content of greater than or equal to 0.45% comprises, by mass percentage, C of 0.135-0.155%, Si of 1.10-1.30%, Mn of 1.70-1.90%, P of less than or equal to 0.015%, S of less than or equal to 0.006%, Al of 0.45-0.55%, Ti of 0.010-0.025%, and the balance of iron and inevitable impurities; Casting: the high-aluminum peritectic steel is continuously cast by using a straight-arc caster; Cooling: the cooling is performed by using a weak cooling mode; During the cooling process, first cooling is performed by using a weak cooling mode, the wide surface cooling water amount is set to 4000 L / min, and the narrow surface cooling water amount is set to 550 L / min; Second cooling is performed, and the specific cooling water amount is controlled to be between 0.64 L / kg steel and 0.71 L / kg steel; Vibration: a non-sine hydraulic vibration mode is used; During the vibration process, the negative slide-out time is less than 0.11 s; Electromagnetic stirring: a roller electromagnetic stirring is used during the continuous casting process; During the electromagnetic stirring process, the stirring current is 400 A, and the frequency is 5 HZ; A special protective slag is used; During the use of the protective slag, the chemical and physical indexes of the protective slag are as follows: Chemical indexes ； Physical indexes ； The contradiction between the requirements of the peritectic steel and the high-aluminum steel for the protective slag is solved, the mold friction is reduced, and the continuous casting of the high-aluminum peritectic steel is realized; It also comprises ladle fork arm calming, and the time is set to be greater than or equal to 8 min; The superheat of the tundish is controlled to be 25-35 DEG C; The control requirement of the insertion depth of the tundish lower nozzle is 125±5 mm.

2. The continuous casting process of a high-aluminium peritectic steel with aluminium content > 0.45% according to claim 1, characterized in that, During the casting process, the used caster parameters are as follows: 。 3. The continuous casting method of a high-aluminum peritectic steel with an aluminum content of > 0.45% according to claim 2, characterized in that, When the 230 mm thick casting blank is produced, the pulling speed is controlled to be 0.85-1.05 m / min, and the target is 0.90 m / min.

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