CN112575143A - Steel cleanliness control method for plastic die steel - Google Patents
Steel cleanliness control method for plastic die steel Download PDFInfo
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- CN112575143A CN112575143A CN202011402379.0A CN202011402379A CN112575143A CN 112575143 A CN112575143 A CN 112575143A CN 202011402379 A CN202011402379 A CN 202011402379A CN 112575143 A CN112575143 A CN 112575143A
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- steel
- furnace
- cleanliness
- controlling
- refining
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0087—Treatment of slags covering the steel bath, e.g. for separating slag from the molten metal
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
Abstract
The invention discloses a control method for steel cleanliness of plastic mould steel, belongs to the technical field of plastic mould flat steel manufacturing, and provides a control method capable of effectively improving the steel cleanliness of the plastic mould flat steel; the method comprises the following steps: step A, when an LF furnace is refined and enters the furnace, lime and refining slag are added simultaneously to adjust the steel alkalinity; step B, LF furnace refining followed by feeding aluminum wire at a wire feed rate of greater than 4.5m/s to reduce the dissolved [ O ] in the steel to <0.0003 wt.%; step C, adopting deoxidation and bottom argon blowing stirring in the LF furnace refining process; and D, controlling aluminum wire feeding in the refining process of the LF furnace to maintain that [ Al ] in the steel is more than or equal to 0.06 wt.%. According to the invention, through innovating a plurality of steel-making processes, the effective control on the steel cleanliness of the plastic die flat steel is finally realized, the steel cleanliness of the plastic die flat steel can be effectively improved, and the grades of A, B, C, D various inclusions can reach 0.5 grade and above respectively.
Description
Technical Field
The invention relates to the technical field of plastic die flat steel manufacturing, in particular to a method for controlling steel cleanliness of plastic die steel.
Background
In plastic die steels, too high a level of non-metallic inclusions can adversely affect the properties of the steel. Sulfides in steel can affect corrosion resistance, particularly pitting corrosion resistance, while reducing the plasticity and toughness of the steel. The presence of oxides and silicates in the steel breaks the continuity of the steel matrix and causes stress concentration, thereby reducing the plasticity, toughness and fatigue resistance of the steel, while also degrading the machinability and polishability of the steel. With the rapid development of the plastic industry, the requirement on the cleanliness of the material of the forming die is higher and higher. Therefore, high cleanliness is a long-sought goal of die steel production enterprises. In order to obtain high-cleanliness steel, the document with the patent application number of CN201610364286.0 adopts an electroslag remelting process, and the grade of A, B, C, D type inclusions of the product is not more than 1.0 grade; patent application No. CN201410334716.5 discloses a steel cleanliness control method for carbon alloy steel, wherein the class B inclusion is only 1.5 grade although [ O ] is less than or equal to 15ppm, and the requirement of high-end plastic die steel is far not met.
Disclosure of Invention
The invention aims to provide a control method capable of effectively improving the steel cleanliness of the plastic mould flat steel.
The technical scheme adopted by the invention for solving the technical problems is as follows: the method for controlling the steel cleanliness of the plastic die steel comprises the following steps:
step A, when the LF furnace is refined and enters the furnace, simultaneously adding lime and refining slag to adjust the steel alkalinity, and controlling the steel alkalinity to be 6.0-10.0;
step B, LF furnace refining followed by feeding aluminum wire at a wire feed rate of greater than 4.5m/s to reduce the dissolved [ O ] in the steel to <0.0003 wt.%;
step C, deoxidizing and stirring by blowing argon from the bottom in the refining process of the LF furnace to make the slag system be calcium-aluminum slag;
and D, controlling aluminum wire feeding in the refining process of the LF furnace to maintain that [ Al ] in the steel is more than or equal to 0.06 wt.%.
Further, the method comprises the following steps: in the step A, the mass ratio of lime to refining slag is 0.9-1.2.
Further, the method comprises the following steps: in the step A, the mass ratio of lime to refining slag is 1.0.
Further, the method comprises the following steps: in the step B, the wire feeding speed is 4.5-5.5 m/s.
Further, the method comprises the following steps: in the step B, the wire feeding speed is 4.5-5 m/s.
Further, the method comprises the following steps: in step B, the aluminum feeding amount is 0.20 percent of the total mass of the molten steel.
Further, the method comprises the following steps: and in the step C, the duration of the deoxidation and the bottom argon blowing stirring is 6-15 min.
Further, the method comprises the following steps: in step D, feeding aluminum wire so that the content of [ Al ] in the steel is 0.06-0.08 wt%
The invention has the beneficial effects that: aiming at the problem of controlling the high steel cleanliness of the existing plastic die steel, the alkalinity of the steel is adjusted by adding corresponding lime and refining slag when an LF furnace is refined and fed into the furnace so as to realize smelting in a slightly alkaline environment, and simultaneously, the content of dissolved [ O ] in molten steel is controlled to be in a low level state all the time in a mode of feeding aluminum wires quickly after the steel is fed into the furnace and selectively feeding the aluminum wires according to requirements in the smelting process; therefore, the high cleanliness of the steel of the plastic die flat steel can be effectively controlled. According to the invention, through innovating a plurality of steel-making processes, the effective control on the steel cleanliness of the plastic die flat steel is finally realized, the steel cleanliness of the plastic die flat steel can be effectively improved, and the grades of A, B, C, D various inclusions can reach 0.5 grade and above respectively.
Detailed Description
The present invention will be further described with reference to the following embodiments.
Example 1:
in this embodiment, the steel cleanliness of the plastic mold steel is controlled by the method for controlling steel cleanliness of plastic mold steel of the present invention, and the specific operations are as follows:
step A, when the LF furnace is refined and enters the furnace, simultaneously adding lime and refining slag to adjust the steel alkalinity, and controlling the steel alkalinity to be 6.5;
step B, LF feeding aluminum wire at a wire feeding speed of 5.0m/s immediately after furnace refining, the feeding amount of aluminum being 0.20% of the total mass of molten steel, so as to rapidly reduce the dissolved [ O ] in steel to 0.00027 wt.% or less; so that the environment in the furnace is quickly adjusted to a state of low dissolution [ O ] and the corresponding negative influence caused by overhigh dissolution [ O ] is avoided;
step C, performing strong stirring for 15min by adopting deoxidation and bottom argon blowing in the refining process of the LF furnace to ensure that a slag system is low-melting-point calcium-aluminum slag with strong adsorption capacity; and Si-containing deoxidizing agent is not used for treatment, so that other substances are prevented from being introduced;
and D, controlling aluminum feeding wires in the refining process of the LF furnace to maintain the [ Al ] in the steel at 0.065 wt.% or above. This is because aluminum is combined with oxygen and then floats up during refining along with the continuous argon blowing process, so that the low oxygen level of the molten steel is maintained by further feeding aluminum wires; of course, the amount of aluminum fed in this step and the timing of aluminum feeding will depend on the real-time variation of the dissolved [ O ] content in the furnace.
The plastic die steel produced by the method of example 1 has high steel cleanliness, and A, B, C, D inclusion grades are all 0.5 grade.
Example 2:
in this embodiment, the steel cleanliness of the plastic mold steel is controlled by the method for controlling steel cleanliness of plastic mold steel of the present invention, and the specific operations are as follows:
step A, when the LF furnace is refined and enters the furnace, simultaneously adding lime and refining slag to adjust the steel alkalinity, and controlling the steel alkalinity to be 8.0;
step B, LF feeding aluminum wire at a wire feeding speed of 5.5m/s immediately after furnace refining, the feeding amount of aluminum being 0.20% of the total mass of molten steel, so as to rapidly reduce the dissolved [ O ] in steel to 0.00025 wt.% or less; so that the environment in the furnace is quickly adjusted to a state of low dissolution [ O ] and the corresponding negative influence caused by overhigh dissolution [ O ] is avoided;
step C, in the refining process of the LF furnace, strong stirring is carried out for 12min by adopting deoxidation and bottom argon blowing, so that the slag system is low-melting-point calcium-aluminum slag with strong adsorption capacity; and Si-containing deoxidizing agent is not used for treatment, so that other substances are prevented from being introduced;
and D, controlling aluminum feeding wires in the refining process of the LF furnace to maintain the [ Al ] in the steel at 0.065 wt.% or above. Of course, the amount of aluminum fed in this step and the timing of aluminum feeding will depend on the real-time variation of the dissolved [ O ] content in the furnace.
The steel cleanliness of the plastic die steel produced by the method in example 2 is high, and the grades of A, B, C, D types of inclusions are respectively 0.5, 0 and 0.5.
Claims (8)
1. The method for controlling the steel cleanliness of the plastic die steel is characterized by comprising the following steps of: the method comprises the following steps:
step A, when the LF furnace is refined and enters the furnace, simultaneously adding lime and refining slag to adjust the steel alkalinity, and controlling the steel alkalinity to be 6.0-10.0;
step B, LF furnace refining followed by feeding aluminum wire at a wire feed rate of greater than 4.5m/s to reduce the dissolved [ O ] in the steel to <0.0003 wt.%;
step C, deoxidizing and stirring by blowing argon from the bottom in the refining process of the LF furnace to make the slag system be calcium-aluminum slag;
and D, controlling aluminum wire feeding in the refining process of the LF furnace to maintain that [ Al ] in the steel is more than or equal to 0.06 wt.%.
2. The method for controlling the steel cleanliness of the plastic mold steel as claimed in claim 1, wherein: in the step A, the mass ratio of lime to refining slag is 0.9-1.2.
3. The method for controlling the steel cleanliness of the plastic mold steel as claimed in claim 2, wherein: in the step A, the mass ratio of lime to refining slag is 1.0.
4. The method for controlling the steel cleanliness of the plastic mold steel as claimed in claim 1, wherein: in the step B, the wire feeding speed is 4.5-5.5 m/s.
5. The method for controlling the steel cleanliness of the plastic mold steel as claimed in claim 4, wherein: in the step B, the wire feeding speed is 4.5-5 m/s.
6. The method for controlling the steel cleanliness of the plastic mold steel as claimed in claim 1, wherein: in step B, the aluminum feeding amount is 0.20 percent of the total mass of the molten steel.
7. The method for controlling the steel cleanliness of the plastic mold steel as claimed in claim 1, wherein: and in the step C, the duration of the deoxidation and the bottom argon blowing stirring is 6-15 min.
8. The method for controlling the steel cleanliness of a plastic mold steel as claimed in any one of claims 1 to 7, wherein: in step D, the aluminum wire is fed so that the proportion of [ Al ] in the steel is 0.06-0.08 wt.%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011402379.0A CN112575143A (en) | 2020-12-02 | 2020-12-02 | Steel cleanliness control method for plastic die steel |
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| CN202011402379.0A CN112575143A (en) | 2020-12-02 | 2020-12-02 | Steel cleanliness control method for plastic die steel |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104087711A (en) * | 2014-07-15 | 2014-10-08 | 攀钢集团江油长城特殊钢有限公司 | Method for improving purity of molten steel and carbon alloy steel ingot |
| CN104630418A (en) * | 2015-01-15 | 2015-05-20 | 南京钢铁股份有限公司 | High-cleanliness pipeline steel smelting process |
| CN105803299A (en) * | 2016-05-30 | 2016-07-27 | 舞阳钢铁有限责任公司 | Production method of extra-thick high-purify plastic mold steel plate |
| CN110724787A (en) * | 2019-10-18 | 2020-01-24 | 东北特殊钢集团股份有限公司 | Smelting method of sulfur-containing and aluminum-containing steel |
| CN111172353A (en) * | 2020-01-03 | 2020-05-19 | 广东韶钢松山股份有限公司 | Method for controlling cleanliness of molten steel and smelting control method for preventing nozzle nodulation in pouring process of sulfur-containing aluminum-containing steel |
| CN111218619A (en) * | 2018-01-31 | 2020-06-02 | 日照钢铁控股集团有限公司 | Preparation process of low-carbon aluminum killed clean steel with slag blocking and wire feeding functions |
-
2020
- 2020-12-02 CN CN202011402379.0A patent/CN112575143A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104087711A (en) * | 2014-07-15 | 2014-10-08 | 攀钢集团江油长城特殊钢有限公司 | Method for improving purity of molten steel and carbon alloy steel ingot |
| CN104630418A (en) * | 2015-01-15 | 2015-05-20 | 南京钢铁股份有限公司 | High-cleanliness pipeline steel smelting process |
| CN105803299A (en) * | 2016-05-30 | 2016-07-27 | 舞阳钢铁有限责任公司 | Production method of extra-thick high-purify plastic mold steel plate |
| CN111218619A (en) * | 2018-01-31 | 2020-06-02 | 日照钢铁控股集团有限公司 | Preparation process of low-carbon aluminum killed clean steel with slag blocking and wire feeding functions |
| CN111424204A (en) * | 2018-01-31 | 2020-07-17 | 日照钢铁控股集团有限公司 | Production process of calcium-treatment-free low-carbon silicon-containing killed clean steel |
| CN110724787A (en) * | 2019-10-18 | 2020-01-24 | 东北特殊钢集团股份有限公司 | Smelting method of sulfur-containing and aluminum-containing steel |
| CN111172353A (en) * | 2020-01-03 | 2020-05-19 | 广东韶钢松山股份有限公司 | Method for controlling cleanliness of molten steel and smelting control method for preventing nozzle nodulation in pouring process of sulfur-containing aluminum-containing steel |
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