阅读说明：本技术 一种超纯净马口铁及其制备方法 (Super-pure tinplate and preparation method thereof ) 是由 邱国兴 李小明 韦旭立 贺芸 白冲 李林波 于 2021-07-22 设计创作，主要内容包括：本发明公开了一种超纯净马口铁及其制备方法,制备方法包括如下过程：在马口铁冶炼过程中,待钢液成分初调整完成后,对钢液成分进行精调整,精调整完成之后进行连铸连轧、浇注为铸坯或连铸为连铸坯；对钢液成分进行精调整时,调整钢液温度至1580～1600℃,之后向钢液中加入含钛脱氧剂,反应2～3min后,再喂铝线进行脱氧。本发明的制备方法即能改善钢液洁净度,还能促使析出了第二相、改善了马口铁的质量,最终得到了性能优异的超纯净马口铁。(The invention discloses an ultra-pure tinplate and a preparation method thereof, wherein the preparation method comprises the following steps: in the smelting process of the tinplate, after the initial adjustment of the components of the molten steel is finished, the components of the molten steel are finely adjusted, and after the fine adjustment is finished, continuous casting and continuous rolling are carried out, and the molten steel is poured into a casting blank or a continuous casting blank; when the components of the molten steel are finely adjusted, the temperature of the molten steel is adjusted to 1580-1600 ℃, then a titanium-containing deoxidizer is added into the molten steel, and after the reaction is carried out for 2-3 min, an aluminum wire is fed for deoxidation. The preparation method of the invention can improve the cleanliness of the molten steel, promote the precipitation of the second phase, improve the quality of the tinplate and finally obtain the ultra-pure tinplate with excellent performance.)

1. A preparation method of ultra-pure tinplate is characterized by comprising the following steps:

in the smelting process of the tinplate, after the initial adjustment of the components of the molten steel is finished, the components of the molten steel are finely adjusted, and after the fine adjustment is finished, continuous casting and continuous rolling are carried out, and the molten steel is poured into a casting blank or a continuous casting blank;

when the components of the molten steel are finely adjusted, the temperature of the molten steel is adjusted to 1580-1600 ℃, then a titanium-containing deoxidizer is added into the molten steel, and after the reaction is carried out for 2-3 min, an aluminum wire is fed for deoxidation.

2. The method for preparing the ultra-pure tinplate as claimed in claim 1, wherein in the process of smelting the tinplate, the tapping temperature of the converter is 1640-1660 ℃, the mass content of phosphorus is less than or equal to 0.04%, and the slag quantity is less than or equal to 4.2kg/t steel;

and initially adjusting the components of the molten steel after tapping of the converter is finished.

3. The method for preparing the ultra-pure tinplate as claimed in claim 1, wherein the initial adjustment of the molten steel components is as follows:

and when the steel is tapped from the converter to 20% of the total volume of the ladle, adding an aluminum ingot for coarse deoxidation, simultaneously adding a slag washing material for slag washing, finishing adding the slag washing material when the steel is tapped to 30% of the total volume of the ladle, and adding a binary alloy and a ternary alloy into the ladle for alloying when the steel is tapped to 50% of the total volume of the ladle.

4. The method of claim 3, wherein the binary alloy is a silicomanganese alloy containing 20-25% by mass of silicon and 75-80% by mass of manganese, the ternary alloy is an aluminum manganese iron alloy containing 15-20%, 15-20% and 60-70% by mass of aluminum, manganese and iron, respectively, and the slag washing material is low SiO₂Pre-melting slag;

wherein the addition amount of the silicon-manganese alloy is 6-7 kg/t steel; the adding amount of the aluminum-manganese-iron alloy is 1-2 kg/t steel; low SiO₂The adding amount of the pre-melted slag is 6-8 kg/t steel.

5. The method of claim 3, wherein the low SiO is₂The pre-melted slag comprises CaO and Al₂O₃、SiO₂MgO and impurities, in mass percent, CaO and Al₂O₃、SiO₂And MgO content of 52-55%, 33-37%, 3.4-3.8% and 1.0-1.5%, and impurity for the rest.

6. The method of claim 3, wherein the mass of aluminum ingot added during the rough deoxidation is the mass of aluminum ingot addedWherein m is_OThe initial oxygen content of the molten steel, and T is the total mass of the molten steel;

after the aluminum ingot is subjected to coarse deoxidation, the oxygen content in the steel is 300-400 ppm.

7. The method for preparing ultra-pure tinplate as claimed in claim 1, wherein the titanium-containing deoxidizer is ferrotitanium containing 60-65% by mass of titanium, and the ferrotitanium is added in an amount to finely adjust the components of molten steelWherein, V_TiThe content of the titanium required by the molten steel finally, and T is the total mass of the molten steel;

the amount of the aluminum wire is 1-2 kg/t steel.

8. The method for preparing the ultra-pure tinplate as claimed in claim 1, wherein the fine adjustment is followed by hot rolling, and the hot rolled slab is cast slab or continuous cast slab obtained by continuous casting, wherein the start temperature of the hot rolling is 1100-1150 ℃ and the finish temperature is 930-960 ℃.

9. The method for preparing the ultra-pure tinplate as claimed in claim 1, wherein the finely adjusted molten steel comprises the following components by mass percent: 0.11 to 0.18 percent of C, 0.001 to 0.002 percent of O, 0.002 to 0.004 percent of N, 0.01 to 0.04 percent of P, 0.01 to 0.02 percent of S, 0.01 to 0.03 percent of Si, 0.3 to 0.4 percent of Mn, 0.02 to 0.04 percent of Ca, 0.03 to 0.07 percent of Ti, 0.03 to 0.05 percent of Al and the balance of iron.

10. An ultra-pure tinplate prepared by the method of any one of claims 1-9.

Technical Field

The invention belongs to the technical field of ferrous metallurgy, and particularly relates to ultra-pure tinplate and a preparation method thereof.

Background

The tinplate has the characteristics of high strength, corrosion resistance, good ductility and no toxicity, and is mainly used for manufacturing food cans, spray cans, bottle cans and gas-containing beverage cans. The tinplate can has the advantage of obvious economic benefit, and the global market demand is gradually increasing. Therefore, in view of long-term demand, there is an urgent need to produce large quantities of high-quality tinplate.

As the packaging materials such as food cans and the like have the characteristic of thin thickness, the tinplate can is required to ensure normal use performance and reduce the thickness to the minimum, but the reduction of the thickness of the tinplate is easy to generate cracks in the can punching process, so that higher requirements are provided for the punching performance of the tinplate. The stamping performance of tinplate is mainly affected by the purity of the steel and the type and amount of the second phase in the steel. At present, most tinplate is produced by aluminum deoxidation, and the purity of steel is low; meanwhile, the pure adoption of aluminum as a main deoxidizer in the steelmaking process can generate brittle long-strip or chain-shaped large-size Al₂O₃And impurities are included, so that the strength of the steel is low. Brittle Al during cold rolling due to the small thickness of the tinplate₂O₃The shape of the inclusion does not change along with the rolling process, so that the brittle inclusion has adverse effect on rolled steel products and is a main inclusion causing edge crack of the pop can. When the second phase is separated out from the steel, fine dispersed particles are distributed in the matrix phase, and the steel is strengthened. However, the existing tinplate production process cannot generate a second phase, so that the second phase strengthening cannot be carried out, and the mechanical property of the tinplate is not facilitatedThe improvement of (1).

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide the ultra-pure tinplate and the preparation method thereof, and the quality of the tinplate is improved from the aspects of improving cleanliness and precipitating a second phase.

The technical scheme adopted by the invention is as follows:

a preparation method of ultra-pure tinplate comprises the following steps:

in the smelting process of the tinplate, after the initial adjustment of the components of the molten steel is finished, the components of the molten steel are finely adjusted, and after the fine adjustment is finished, continuous casting and continuous rolling are carried out, and the molten steel is poured into a casting blank or a continuous casting blank;

when the components of the molten steel are finely adjusted, the temperature of the molten steel is adjusted to 1580-1600 ℃, then a titanium-containing deoxidizer is added into the molten steel, and after the reaction is carried out for 2-3 min, an aluminum wire is fed for deoxidation.

Preferably, in the smelting process of the tinplate, the tapping temperature of the converter is 1640-1660 ℃, the mass content of phosphorus is less than or equal to 0.04%, and the slag amount is less than or equal to 4.2kg/t steel;

and initially adjusting the components of the molten steel after tapping of the converter is finished.

Preferably, when the components of the molten steel are initially adjusted:

and when the steel is tapped from the converter to 20% of the total volume of the ladle, adding an aluminum ingot for coarse deoxidation, simultaneously adding a slag washing material for slag washing, finishing adding the slag washing material when the steel is tapped to 30% of the total volume of the ladle, and adding a binary alloy and a ternary alloy into the ladle for alloying when the steel is tapped to 50% of the total volume of the ladle.

Preferably, the binary alloy is a silicon-manganese alloy containing 20-25% of silicon by mass and 75-80% of manganese by mass, the ternary alloy is an aluminum-manganese-iron alloy containing 15-20%, 15-20% and 60-70% of aluminum, manganese and iron by mass respectively, and the slag washing material is low SiO₂Pre-melting slag;

wherein the addition amount of the silicon-manganese alloy is 6-7 kg/t steel; the adding amount of the aluminum-manganese-iron alloy is 1-2 kg/t steel; low SiO₂The adding amount of the pre-melted slag is 6-8 kg/t steel.

Preferably, low SiO₂The pre-melted slag comprises CaO and Al₂O₃、SiO₂MgO and impurities, in mass percent, CaO and Al₂O₃、SiO₂The MgO, the MgO and the MgO are respectively 52-55%, 33-37%, 3.4-3.8% and 1.0-1.5% in percentage by mass, and the balance is impurities.

Preferably, the mass of the added aluminum ingot is selected when the aluminum ingot is added for coarse deoxidationWherein m is_oThe initial oxygen content of the molten steel, and T is the total mass of the molten steel;

after the aluminum ingot is subjected to coarse deoxidation, the oxygen content in the steel is 300-400 ppm.

Preferably, when the molten steel components are finely adjusted, the titanium-containing deoxidizer adopts 60 to 65 mass percent of ferrotitanium, and the amount of the ferrotitanium addedWherein, V_TiThe content of the titanium required by the molten steel finally, and T is the total mass of the molten steel;

the amount of the aluminum wire is 1-2 kg/t steel.

Preferably, hot rolling is carried out after the fine adjustment is finished, and a cast blank obtained by pouring or a continuous casting blank obtained by continuous casting is adopted as a hot rolled slab, wherein the hot rolling start temperature is 1100-1150 ℃, and the finish rolling temperature is 930-960 ℃.

Preferably, the finely adjusted molten steel comprises the following components in percentage by mass: 0.11 to 0.18 percent of C, 0.001 to 0.002 percent of O, 0.002 to 0.004 percent of N, 0.01 to 0.04 percent of P, 0.01 to 0.02 percent of S, 0.01 to 0.03 percent of Si, 0.3 to 0.4 percent of Mn, 0.02 to 0.04 percent of Ca, 0.03 to 0.07 percent of Ti and 0.03 to 0.05 percent of Al.

The invention also provides the ultra-pure tinplate prepared by the preparation method.

The invention has the following beneficial effects:

the inventionIn the preparation method of the ultra-pure tinplate, after the initial adjustment of the components of the molten steel is finished, the components of the molten steel are finely adjusted, when the components of the molten steel are finely adjusted, the temperature of the molten steel is adjusted to 1580-1600 ℃, then a titanium-containing deoxidizer is added into the molten steel, and after the reaction is carried out for 2-3 min, an aluminum wire is fed for deoxidation; deoxidizing with Ti-containing deoxidizing agent at 1580-1600 deg.C to generate different titanium oxides, such as Ti₂O₃And TiO₂，Ti₂O₃Can induce to form in-grain ferrite to finally refine grains, has obvious effect on improving the performance of the tin plate, and can ensure that Ti can be used when the temperature of molten steel is 1580-1600 DEG C₂O₃Has a higher precipitation rate than TiO₂Thus being beneficial to refining grains. Meanwhile, the residual Ti element in the steel can be precipitated in the form of TiN and TiC in the subsequent hot working process, so that the second phase strengthening effect is achieved, and the mechanical property of the steel is improved. Compared with pure aluminum deoxidation, the titanium-aluminum composite deoxidation process can obviously reduce the total oxygen content in steel and improve the cleanliness of molten steel. In conclusion, the preparation method of the invention improves the cleanliness of the molten steel, promotes the precipitation of the second phase, improves the quality of the tinplate and obtains the ultra-pure tinplate.

Furthermore, in the smelting process of the tinplate, the tapping temperature of the converter is 1640-1660 ℃, and the tapping temperature can guarantee smooth proceeding of subsequent processes within the range, needs to be matched with the refining temperature, guarantees the temperature required by refining, lays a foundation for deoxidation in the refining process, and is more favorable for improving the purity of the tinplate; the mass content of phosphorus is less than or equal to 0.04 percent, P can cause cold brittleness of steel, and if the phosphorus is too high, the toughness requirement of the tinplate can not be met, so the phosphorus content is controlled within the range. The slag amount is less than or equal to 4.2kg/t steel, and the slag amount greatly influences the purity of molten steel to cause rephosphorization, so the slag amount needs to be controlled in the range to meet the production of the tinplate.

Furthermore, when the components of the molten steel are initially adjusted, the molten steel is stirred violently when the steel is tapped to 20%, and the deoxidizer and the slag washing material are added to be beneficial to enhancing the full contact of the inclusions in the steel and the slag washing material, so that the coarse deoxidation and the impurity removal of the molten steel are promoted. The reason that the alloy is added for alloying when the tapping reaches 50 percent is that the aluminum ingot is added for coarse deoxidation, and the alloying by adding the alloy is more beneficial to the utilization of the alloy in molten steel, so that the alloy yield is improved. The molten steel added later also plays a role in stirring, and favorable conditions are provided for purifying the molten steel.

Further, the binary alloy is a silicon-manganese alloy containing 20-25% of silicon and 75-80% of manganese, and the silicon-manganese alloy can reduce the total oxygen content and nitrogen content of the tinplate and reduce the sizes of A-type inclusions and D-type inclusions in steel; the ternary alloy is an aluminum-manganese-iron alloy with the aluminum, manganese and iron contents of 15-20%, 15-20% and 60-70%, and the aluminum-manganese-iron alloy can form a manganese-rich area around aluminum, improve the solubility and the deoxidation capability of the aluminum, generate a low-melting-point composite deoxidation product, greatly reduce the inclusion content in steel and improve the purity of molten steel. The tinplate is produced by adopting a deoxidation alloying process of matching the silicon-manganese alloy and the aluminum-manganese-iron alloy, so that the addition of the alloy in steel can be ensured, the produced molten steel can be cleaner, and the requirement of the tinplate on cleanliness can be better met. The slag washing material is selected from low SiO₂Pre-melting slag; low SiO₂The slag system can effectively reduce the phenomena of recarburization and silicification of the tinplate, reduce the content of impurities in steel and improve the quality of various steel products.

Further, after the aluminum ingot is subjected to coarse deoxidation, the oxygen content in the steel is 300-400 ppm, preparation is made for subsequent deep deoxidation, and the pressure of the subsequent deep deoxidation is reduced.

Furthermore, the hot rolling start rolling temperature is 1100-1150 ℃, the finish rolling temperature is 930-960 ℃, and TiN particles with smaller size can be separated out at the start rolling temperature and the finish rolling temperature to produce precipitation strengthening, so that the performance of the steel is strengthened.

Detailed Description

The present invention will be further described with reference to the following examples.

In the preparation method of the ultra-pure tinplate, firstly, aluminum ingot is subjected to coarse deoxidation, and then, titanium and aluminum are subjected to deep deoxidation, and the preparation method specifically comprises the following steps:

(1) converter tapping end point control

The tapping temperature of the converter is 1640-1660 ℃, P is less than or equal to 0.04%, and the slag discharging amount is less than or equal to 4.2kg/t steel.

(2) Initial adjustment of molten steel composition

And when the steel is tapped from the converter to 20 percent of the total volume of the steel ladle, adding an aluminum ingot for coarse deoxidation, simultaneously adding a slag washing material for slag washing, and finishing tapping to 30 percent of the total volume of the steel ladle. And adding a binary alloy and a ternary alloy into the ladle for alloying when tapping is carried out until the total volume of the ladle is 50 percent. The binary alloy is a silicon-manganese alloy with the silicon content of 20-25 percent by mass and the manganese content of 75-80 percent by mass, the ternary alloy is an aluminum-manganese-iron alloy with the aluminum, manganese and iron content of 15-20 percent, 15-20 percent and 60-70 percent respectively, and the slag washing material is low SiO₂Pre-smelting slag. Adding 6-7 kg/t silicon-manganese alloy steel, 1-2 kg/t aluminum-manganese-iron steel and low SiO₂6-8 kg/t of premelting slag steel is added with low SiO₂The pre-melted slag comprises the following main components: CaO 52-55%, Al₂O₃ 33％～37％、SiO₂3.4 to 3.8 percent of MgO and 1.0 to 1.5 percent of MgO. Adding aluminum ingot amount in coarse deoxidationWherein m is_OIs the initial oxygen content of the molten steel in unit kg; t is the total mass of the molten steel in kg. Sampling and measuring the oxygen content in the steel after coarse deoxidation, wherein the oxygen content in the steel is coarsely removed to 300-400 ppm.

(3) Fine adjustment of molten steel composition

The method comprises the steps of carrying out deep deoxidation by adopting a titanium-aluminum composite deoxidation process, adjusting the temperature of molten steel to 1580-1600 ℃, adding a titanium-containing deoxidizer, reacting for 2-3 min, and then feeding an aluminum wire for deoxidation. Wherein, the titanium-containing deoxidizer adopts ferrotitanium with 60 to 65 percent of titanium. Adding ferrotitanium in an amount ofWherein, V_TiThe titanium content finally required by the molten steel; t is the total mass of the molten steel in kg. Feeding 1-2 kg/t steel by the total mass of the aluminum wire.

After the fine adjustment of the components of the molten steel is finished, the molten steel contains 0.03 to 0.07 percent of Ti, 0.03 to 0.05 percent of Al and less than or equal to 20 multiplied by 10 percent of oxygen by mass percent^-6Nitrogen content20×10^-6～40×10^-6. The tinplate comprises the following main components: 0.11 to 0.18 percent of C, 0.001 to 0.002 percent of O, 0.002 to 0.004 percent of N, 0.01 to 0.04 percent of P, 0.01 to 0.02 percent of S, 0.01 to 0.03 percent of Si, 0.3 to 0.4 percent of Mn, 0.02 to 0.04 percent of Ca, 0.03 to 0.07 percent of Ti, 0.03 to 0.05 percent of Al and the balance of iron.

(4) Rolling process

And carrying out hot rolling after continuous casting, and carrying out cold rolling after slow cooling, wherein the initial rolling temperature of the hot rolling is 1100-1150 ℃, and the final rolling temperature is 930-960 ℃.

Example 1

The preparation method of the ultra-pure tinplate comprises the following steps:

(1) converter tapping end point control

The total mass of converter tapping is 100 tons, the tapping temperature is 1640-1660 ℃, the mass percentage content of P is 0.04%, and the slag discharge amount is 4.2kg/t steel.

(2) Initial adjustment of molten steel composition

And when the steel is tapped from the converter to 20 percent of the total volume of the steel ladle, adding an aluminum ingot for coarse deoxidation, simultaneously adding a slag washing material for slag washing, and finishing tapping to 30 percent of the total volume of the steel ladle. When tapping is carried out to 50% of the total volume of the steel ladle, adding a silicon-manganese alloy and an aluminum-manganese-iron alloy into the steel ladle, wherein the silicon-manganese alloy contains 25% by mass of silicon and 75% by mass of manganese; in the aluminum-manganese-iron alloy, the mass contents of aluminum, manganese and iron are respectively 18%, 19% and 63%; the slag washing material is selected from low SiO₂Premelted slag, low SiO₂The pre-melted slag comprises the following main components in percentage by mass: CaO 55%, Al₂O₃ 37％、SiO₂3.8 percent and 1.5 percent of MgO. Wherein, 7kg/t steel of silicon-manganese alloy, 2kg/t steel of aluminum-manganese-iron and low SiO are added₂Pre-melting 8kg/t steel. The amount of aluminum ingot added in the coarse deoxidation is m_AlAfter coarse deoxidation, sampling is carried out to measure the oxygen content in the steel, and the oxygen content in the steel is coarsely removed to 312 ppm.

(3) Fine adjustment of molten steel composition

Performing deep deoxidation by adopting a titanium-aluminum-first composite deoxidation process, and adjusting the temperature of molten steel to 1580-16 DEGAfter 00 ℃, a titanium-containing deoxidizer, namely ferrotitanium containing 65 percent of titanium, is added, and after reaction for 3min, an aluminum wire is fed for deoxidation. Wherein the added ferrotitanium is m_TiFe108kg, the total mass of the aluminum wire is 2kg/t steel.

After the fine adjustment of the components of the molten steel is finished, the molten steel contains 0.07 percent of Ti and 0.05 percent of Al by mass percent, and the oxygen content in the steel is 19 multiplied by 10^-6Nitrogen content 37X 10^-6. The tinplate comprises the following main components: 0.11% of C, 0.0019% of O, 0.0037% of N, 0.04% of P, 0.02% of S, 0.03% of Si, 0.4% of Mn, 0.04% of Ca, 0.07% of Ti, 0.05% of Al and the balance of iron.

(4) Rolling process

Carrying out hot rolling after continuous casting, carrying out cold rolling after slow cooling, wherein the initial rolling temperature of the hot rolling is 1150 ℃, and the final rolling temperature is 960 ℃.

The mechanical property parameters of the ultra-pure tinplate prepared by the implementation are shown in table 1:

TABLE 1

Yield strength/MPa	Tensile strength/MPa	Impact toughness/J	Average size of inclusions/um	Second phase analysis yield/%)
					236	346	40	0.8	47

Example 2

The preparation method of the ultra-pure tinplate comprises the following steps:

(1) converter tapping end point control

The total mass of converter tapping is 120 tons, the tapping temperature is 1640-1660 ℃, the mass percentage content of P is 0.03 percent, and the slag discharge amount is 3.9kg/t steel.

(2) Initial adjustment of molten steel composition

And when the steel is tapped from the converter to 20 percent of the total volume of the steel ladle, adding an aluminum ingot for coarse deoxidation, simultaneously adding a slag washing material for slag washing, and finishing tapping to 30 percent of the total volume of the steel ladle. When tapping is carried out to 50% of the total volume of the steel ladle, adding a silicon-manganese alloy and an aluminum-manganese-iron alloy into the steel ladle, wherein the silicon-manganese alloy contains 22% by mass of silicon and 78% by mass of manganese; in the aluminum-manganese-iron alloy, the mass contents of aluminum, manganese and iron are respectively 17%, 16% and 67%; the slag washing material is selected from low SiO₂Premelted slag, low SiO₂The pre-melted slag comprises the following main components in percentage by mass: CaO 55%, Al₂O₃ 36％％、SiO₂3.5 percent and 1.4 percent of MgO. Wherein, 6kg/t steel of silicon-manganese alloy, 1kg/t steel of aluminum-manganese-iron and low SiO are added₂6kg/t of premelting slag steel. The amount of aluminum ingot added in the coarse deoxidation is m_Al84 kg. After coarse deoxidation, sampling is carried out to measure the oxygen content in the steel, and the oxygen content in the steel is coarsely removed to 398 ppm.

(3) Fine adjustment of molten steel composition

The method comprises the steps of carrying out deep deoxidation by adopting a titanium-aluminum-first composite deoxidation process, adjusting the temperature of molten steel to 1580-1600 ℃, adding a titanium-containing deoxidizer, namely 65% titanium-containing iron, reacting for 2min, and then feeding an aluminum wire for deoxidation. Wherein the added ferrotitanium is m_TiFeThe total mass of the aluminum wire is fed to the steel at 56kg, and the total mass of the aluminum wire is 1 kg/t.

After the fine adjustment of the components of the molten steel is finished, the molten steel contains 0.03 percent of Ti and 0.03 percent of Al by mass percent, and the oxygen content in the steel is 16 multiplied by 10^-6Nitrogen content 33X 10^-6. The tinplate comprises the following main components: 0.13% of C, 0.0016% of O, 0.0033% of N, 0.0% of P3%, S0.01%, Si 0.01%, Mn 0.3%, Ca 0.02%, Ti 0.03%, Al 0.03%, and the balance of iron.

(4) Rolling process

Carrying out hot rolling after continuous casting, carrying out cold rolling after slow cooling, wherein the initial rolling temperature of the hot rolling is 1100 ℃, and the final rolling temperature is 930 ℃.

The mechanical property parameters of the ultra-pure tinplate prepared by the implementation are shown in table 2:

TABLE 2

Yield strength/MPa	Tensile strength/MPa	Impact toughness/J	Average size of inclusions/um	Second phase analysis yield/%)
					184	286	32	1.1	40

Example 3

The preparation method of the ultra-pure tinplate comprises the following steps:

(1) converter tapping end point control

The total mass of converter tapping is 150 tons, the tapping temperature is 1640-1660 ℃, the mass percentage content of P is 0.03 percent, and the slag discharge amount is 3.8kg/t steel.

(2) Initial adjustment of molten steel composition

And when the steel is tapped from the converter to 20 percent of the total volume of the steel ladle, adding an aluminum ingot for coarse deoxidation, simultaneously adding a slag washing material for slag washing, and finishing tapping to 30 percent of the total volume of the steel ladle. When tapping is carried out to 50% of the total volume of the steel ladle, adding a silicon-manganese alloy and an aluminum-manganese-iron alloy into the steel ladle, wherein the silicon-manganese alloy contains 25% by mass of silicon and 75% by mass of manganese; in the aluminum-manganese-iron alloy, the mass contents of aluminum, manganese and iron are respectively 20%, 20% and 60%; the slag washing material is selected from low SiO₂Premelted slag, low SiO₂The pre-melted slag comprises the following main components in percentage by mass: 54% of CaO and Al₂O₃ 34％、SiO₂3.7 percent and 1.2 percent of MgO. Wherein 6.6kg/t steel of silicon-manganese alloy, 1.4kg/t steel of aluminum-manganese-iron and low SiO are added₂Premelting slag is 7kg/t steel. The amount of aluminum ingot added in the coarse deoxidation is m_Al106kg, sampling after rough deoxidation to measure the oxygen content in the steel, and roughly removing the oxygen content in the steel to 347 ppm.

(3) Fine adjustment of molten steel composition

The method comprises the steps of carrying out deep deoxidation by adopting a titanium-aluminum-first composite deoxidation process, adjusting the temperature of molten steel to 1580-1600 ℃, adding a titanium-containing deoxidizer, namely 65% titanium-containing iron, reacting for 2min, and then feeding an aluminum wire for deoxidation. Wherein the added ferrotitanium is m_TiFe130kg, feeding 1kg/t steel of the total mass of the aluminum wire.

After the fine adjustment of the components of the molten steel is finished, the molten steel contains 0.06 percent of Ti and 0.04 percent of Al by mass percent, and the oxygen content in the steel is 15 multiplied by 10^-6Nitrogen content 27X 10^-6. The tinplate comprises the following main components: 0.12% of C, 0.0015% of O, 0.0027% of N, 0.03% of P, 0.01% of S, 0.01% of Si, 0.3% of Mn, 0.02% of Ca, 0.06% of Ti, 0.04% of Al and the balance of iron.

(4) Rolling process

Carrying out hot rolling after continuous casting, carrying out cold rolling after slow cooling, wherein the initial rolling temperature of the hot rolling is 1125 ℃, and the final rolling temperature is 945 ℃.

The mechanical performance parameters of the ultra-pure tinplate prepared by the implementation are shown in table 3:

TABLE 3

Yield strength/MPa	Tensile strength/MPa	Impact toughness/J	Average size of inclusions/um	Second phase analysis yield/%)
					211	312	35	0.9	44