Method for controlling contents of phosphorus, sulfur and hydrogen in molten steel
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A technology of hydrogen content and molten steel, applied in the manufacture of converters and other directions, can solve the problems of easy to increase N, inability to remove H in the LF refining process, and large demand for scrap steel.
Active Publication Date: 2013-10-30
SHOUGANG CORPORATION
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However, the amount of top slag modified slag is generally controlled at 3-5Kg / ton of steel, which cannot guarantee a large amount of desulfurization during the tapping process.
[0004] In addition, due to the large demand for steel scrap and the management of scrap steel in most steel mills in China, most of the steel grades with [S]≤0.006% are produced by LF process, but the LF refining process cannot remove H, and the treatment process is easy to increase N , and its inclusion control level is also worse than that of the RH refining process
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Embodiment 1
[0046] 1) Pretreatment of KR molten iron, the temperature of KR molten iron is 1372°C, the amount of desulfurizer added is 2.4t, the stirring time is 10min, the sulfur content after treatment is 0.002%, the temperature of molten iron is 1348°C, and the slag removal rate is >95%;
[0047] 2) The weight of molten iron in the dephosphorization converter is 291t, and the scrap is high-quality scrap: medium-sized scrap: baled block: aggregate scrap: slag steel: light scrap = 7t: 10t: 4t: 5t: 5t: 5t, after smelting [C] =3.6%, [P]=0.026%, [S]=0.0073%, temperature 1345℃;
[0048] 3) C=0.041%, [P]=0.0058%, [S]=0.0082% of molten steel at the end point of decarburization converter smelting, the end point oxygen is 580ppm, and the temperature is 1685°C;
[0049] 4) Add 1680Kg of small grain lime and 460Kg of fluorite when the tapping amount is 1 / 5;
[0050] 5) Add 1.32 tons of aluminum and iron when the tapping amount is 2 / 5;
[0051] 6) The online bottom blowing flow rate in the tapping ...
Embodiment 2
[0055] 1) Pretreatment of KR molten iron, the temperature of KR molten iron is 1368°C, the amount of desulfurizer added is 2.3t, the stirring time is 9min, the sulfur content after treatment is 0.001%, the temperature of molten iron is 1345°C, and the slag removal rate is >95%;
[0056] 2) The weight of molten iron in the dephosphorization converter is 290t, and the scrap steel is high-quality scrap steel: medium-sized scrap steel: baled block: combined scrap steel: slag steel: light scrap steel = 7t: 10t: 4t: 5t: 5t: 5t, after smelting [C] =3.5%, [P]=0.028%, [S]=0.0078%, temperature 1356℃;
[0057] 3) C=0.035%, [P]=0.0052%, [S]=0.0091% of molten steel at the end point of decarburization converter smelting, the end point oxygen is 610ppm, and the temperature is 1678°C;
[0058] 4) Add 1630Kg of small grain lime and 450Kg of fluorite when the tapping amount is 1 / 5;
[0059] 5) Add 1.37 tons of aluminum and iron when the tapping amount is 2 / 5;
[0060] 6) The online bottom blo...
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Abstract
The invention relates to a method for controlling the contents of phosphorus, sulfur and hydrogen in molten steel. The method comprises the following steps: performing molten iron pretreatment with a knotted reactor (KR) to desulphurize; placing the desulphurized molten iron in a dephosphorization converter to dephosphorize; placing the dephosphorized molten iron in a decarburization converter to smelt; tapping from the decarburization converter, adding ferroaluminum to deoxidize, and adding slag to adjust the slag basicity; and performing Ruhrstahl-Heraeus (RH) refinement. In the method for controlling the contents of phosphorus, sulfur and hydrogen in molten steel, molten iron pretreatment for desulfurization and dephosphorization are adopted, and waste steel which has low sulfur content and is easy to melt is used, thus P is no more than 60ppm and S is no more than 100ppm in the endpoint of the converter; the dosages of aluminum and slag and the addition time are controlled in the topping process of the converter to realize the effects of slag washing and desulfurization and ensure that P is no more than 80ppm and S is no more than 60ppm in the RH refinement; and after RH refinement is performed to degas and refine, the aim of smelting the steel with low contents of phosphorus, sulfur and hydrogen can be realized.
Description
technical field [0001] The invention relates to a method for controlling the contents of phosphorus, sulfur and hydrogen in molten steel. Background technique [0002] At present, in most steelmaking plants at home and abroad, dephosphorization of molten iron is carried out simultaneously with decarburization in conventional converters, and it is difficult to ensure [P]≤0.006% stably after smelting; but conventional converter smelting can use self-circulating scrap steel in the plant , such as tundish casting waste, billet head, etc., such scrap steel has low sulfur content and stable quality, and converter tapping can guarantee a low S content. Generally, [S]≤0.006% can be achieved at the end of converter smelting, but the dephosphorization converter process is adopted , due to the short blowing time, low temperature, and difficulty in melting scrap steel, it is impossible to use self-circulating scrap steel in the factory. It is necessary to select scrap steel with a suita...
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