CN1644713A - Effective integrated slag for deoxidising, slag cleansing and externally refining for steelmaking and its use - Google Patents

Abstract

The invention is to produce the special cinder by pneumatic steelmaking especially for the cinder of deoxidizing, wash heat and refinement. The cinder is self-fluxing nature or partial self-fluxing nature which is compose dof CaO 35-75%, SiO24%, P0.04%, Al2O3 10-30%, MgO 65, S0.04%. according to the process of smelting and refinement, steel grade, the kind of product, we can decide the mixture ratio and added quantity. Also put into the ladle by one or many times after tapping off 30S, and stop at the time of 2/3-3/4 tapping. It has the low melting point and high sulfur remove and the adsorptive of deoxidized production. Also it can reduce the quantity of inclusion of the steel and the energy of the finer. So it can improve the quality of the product. It is benefit to the end to end of the process and the factory.

Description

Deoxidation in steel making-wash heat-external refining is with effective integrated slag and using method

Technical field

The invention belongs to converter steelmaking production special composition slag, relate in particular to the slag charge of steel-making with deoxidation, wash heat and external refining.

Background technology

Aluminium killed steel and silicon-aluminium killed steel purposes is very extensive, and the steel of various uses is also very strict to performance requriements, or requires high strength and toughness good comprehensive performances, or requires suitable intensity, good plasticity and low folder thing content, or requires low sulfur content etc.Under the prerequisite that guarantees product performance, strict control inclusion content, size, type and distribution are particularly important.Therefore, have higher requirement, smelting, refinery practice have also been proposed to optimize and reset requirement for aluminium killed steel and silicon-aluminium killed steel Control and Inclusion Removal technology.Particularly, all need to adopt the optimization of smelting, refinery practice and reset to guarantee to high performance sheet material, the easy wire drawing of low-carbon (LC), cold heading steel, high-quality medium high carbon rigid line and deep processing excellent high-carbon wire rods etc.The task part of refining procedure is preposition, and the deoxidation alloying of smelting technology is born part refining procedure task, finishes deoxidation, wash heat and has made refining slag in advance in the deoxidation alloying operation of tapping process.

But, in the prior art, adopt modification slag, refining slag and other wash heat material, for guaranteeing fusing point≤1420 ℃, all adopt high-load Al ₂O ₃And SiO ₂, general Al ₂O ₃〉=35% and SiO ₂〉=7-8%.

High Al ₂O ₃Content has brought the Al of slag ₂O ₃A little less than the adsorptive power, that finally causes product is mingled with the content height, and Particulate Inclusion is big, has influenced the performance of steel, has limited the range of application of product; High Al ₂O ₃Content also can cause in the molten steel casting process and hold stream, and the production aluminium killed steel that Here it is prior art slag system exists and silicon-aluminium killed steel are difficult to overcome is mingled with and holds flow problem.

High SiO ₂Content can cause refining to make that molten steel returns silicon in reductibility slag, the refining process, thereby the low-silicon steel kind product that can't guarantee Si≤0.03% is produced smoothly, and the silicone content height is for sheet material, can't satisfy the coating requirement, influence coating performance, cold-bending property and the deep drawability of sheet material; For soft steel wire rod and cold heading steel wire rod, influence its drawing, cold-heading and weldability.Subject matter and product performance problem that the low-silicon steel of prior art slag system existence that Here it is is difficult to produce.

In addition, present refining and slagging process major part are to carry out at the LF stove, because the melt cinder of needsization slag time and formation floats on the molten steel face, even having under the situation of gas stirring, the contact of slag steel is still insufficient, influences the dynamic conditions of desulfurization, causes desulfuration efficiency not high.Often running into sulphur content in actual production is difficult to remove and influence production and product performance.

Summary of the invention

In order to overcome the defective that prior art exists, the purpose of this invention is to provide a kind of deoxidation in steel making, wash heat, the effective integrated slag of external refining, reduce in the steel and be mingled with content, reduce and control is mingled with size, improve desulfuration efficiency, reduce or eliminate the stream that holds in aluminium killed steel, the silicon-aluminium killed steel casting process, can control or reduce back silicon for low-silicon steel.

Another object of the present invention provides a kind of using method of above-mentioned effective integrated slag.

Deoxidation in steel making-wash heat of the present invention-external refining is self-fluxing nature or part self-fluxing nature slag with effective integrated slag, and this slag system is composed of the following components by weight percentage:

CaO???????35-75％

SiO ₂?????≤4％

P?????????≤0.04％

Al ₂O ₃???10-30％

MgO???????≤6％

S?????????≤0.04％

The composition design of effective integrated slag of the present invention is based on polynary system phasor principle, adopts up-to-date polynary system Study of Phase Diagram achievement, the design appropriate ingredients, and the high absorption property of assurance refining top slag is than low melting point and high Sulfur capacity.Adopt low Al ₂O ₃The content composition reduces high Al ₂O ₃The macrobead that brings of content indeformablely be mingled with and be mingled with the harm that the content height brings.The composition of integrated slag meets low melting point (≤1410 ℃～1400 ℃), has the adsorptivity of part deoxidation and high deoxidation products and guarantees refining top slag high-sulfur capacitive, promptly high desulphurizing ability; Adopt part fritting or rational design mix, make slag have self-fluxing nature or part self-fluxing nature, make the deoxidation products of generation be adsorbed the back, under molten steel temperature, be in a liquid state, and in subsequent handling, from molten steel, discharge easily in conjunction with the deoxidation products that generates.

Deoxidation in steel making-wash heat of the present invention-external refining is with the using method of effective integrated slag:

One, add-on is according to the refinery practice of smelting, and promptly steel grades, range of product are joined type, add-on definite the composition:

A, low-carbon (LC), Ultra-low carbon steel grade sheet material: according to steel grade desulfurization requirement, 8-12Kg/t steel;

B, general carbon plate material: according to steel grade desulfurization requirement, 6-16Kg/t steel;

C, high-strength panel: according to steel grade desulfurization requirement, 6-15Kg/t steel;

D, low-carbon (LC) wire rod: according to steel grade desulfurization requirement, 5-18Kg/t steel;

E, cold-heading wire rod: according to steel grade desulfurization requirement, 6-15Kg/t steel;

F, middle carbon, general carbon line material: according to steel grade desulfurization requirement, 4-12Kg/t steel;

G, high-carbon wire rod: according to steel grade desulfurization requirement, 5-10Kg/t steel.

Two, adding method

A, tapping process add ladle with steel stream;

B, tapping begin in the time of 30 seconds to add, and add or once add in batches ladle;

C, tapping added in 2/3～3/4 time.

Adopt the effective integrated slag of the present invention, in tapping deoxidization alloy operation process, finish deoxidation, tapping process wash heat and tapping process and made refining slag in advance, thereby guaranteed before entering refining furnace the generation of liquid or most of liquid slag, the liquid slag that generates, both had low fusibleness, had the adsorptivity of part deoxidation and high deoxidation products again, had high desulphurizing ability simultaneously.Make the deoxidation products of generation be adsorbed the back in conjunction with the deoxidation products that generates, under molten steel temperature, be in a liquid state, and at follow-up refining process, from molten steel, discharge in the calm time before continuous casting working procedure, inclusion in the product is other tiny smelting procedure inclusion of a spot of, secondary fine deoxidation products and minute quantity, and it is low that molten steel contains the S amount.So both reduce inclusion content, reduced the inclusion size, reduced S content, reduced the pressure of refinery practice simultaneously, reduced the change slag time of refinery practice, alleviated the burden that the removal of refinery practice is mingled with.

Compared with prior art, its advantage is: low melting point, and fusing point (≤1410 ℃～1400 ℃), slagging and the height that is beneficial to melt cinder is mingled with adsorptive power, high desulfurization slag generates in advance; Adsorptivity with part deoxidation and high deoxidation products; Low Al ₂O ₃Content reduces the harm that macrobead is mingled with in the steel; Guarantee refining top slag high-sulfur capacitive; Have self-fluxing nature or part self-fluxing nature, reduce the energy consumption of refining furnace slag, shortened the change slag time, reduced production cost, help procedure connection and organization of production; Low SiO ₂Content, time silicon of control or minimizing low-silicon steel kind refining process fully.

Embodiment

Further specify the present invention below by embodiment and Comparative Examples.Use in the following Examples and Comparative Examples fusing point (℃) fusibility of expression slag, the easy more slagging of the low more melt cinder of fusing point, high desulfurization slag and wash heat slag generate more in advance, it is strong more to be mingled with adsorptive power; Low Al ₂O ₃Content is represented Al in the slag absorption steel ₂O ₃Ability is strong, guarantees low Al in the steel ₂O ₃Be mingled with content, because the strong adsorptive power of wash heat and slag, thereby the inclusion size reduced, Al in the slag ₂O ₃Content is low more, slag absorption Al ₂O ₃It is strong more to be mingled with ability, inclusion more less, tiny more.

The slag system of listing in the table of the present invention has strong sweetening power.

The low SiO of this slag system ₂Can reduce and return silicon, SiO in the refining process steel ₂Content is low more, and time silicon is few more.

Embodiment 1, at normal temperatures and pressures presses specified each component (CaO65.95%, SiO in the table 1 respectively ₂2.49%, Al ₂O ₃20.20%, MgO ₂.11%, Fe ₂O ₃0.2%, P0.041%, S0.039%) process, in table 1, listed test result.

Embodiment 2, at normal temperatures and pressures, press specified each component (CaO65.95%, SiO in the table 1 respectively ₂2.79%, Al ₂O ₃24.81%, MgO1.81%, Fe0.24%, P0.038%, S0.036%) method that repeats embodiment 1 listed test result in table 1.

Embodiment 2, at normal temperatures and pressures, press specified each component (CaO70.70%, SiO in the table 1 respectively ₂2.49%, Al ₂O ₃14.60%, MgO1.81%, Fe＜0.20%, P0.025%, S0.040%) method that repeats embodiment 1 listed test result in table 1.

Comparative Examples 1, CaO48.28%, SiO ₂4.58%, Al ₂O ₃40.94%, MgO1.00%.

Comparative Examples 1, CaO48.13%, SiO ₂5.94%, Al ₂O ₃39.89%, MgO1.23%.

Comparative Examples 1, CaO47.02%, SiO ₂4.53%, Al ₂O ₃40.35%, MgO1.67%.

The slag system component and the fusing point of prior art have been listed in the table 2.

Table 1

Component	The actual detected fusing point	CaO	?SiO 2	?Al 2O 3	?MgO	??FeO	??P	??S
									????1	????1400℃	65.95	?2.49	?20.20	?2.11	????0.26	?0.041	?0.039
????2	????1397℃	65.95	?2.79	?24.81	?1.81	????0.24	?0.038	?0.036
									????3	????1397℃	70.70	?2.49	?14.60	?1.81	????＜0.20	?0.025	?0.040

Table 2

	??CaO	??SiO 2	??Al 2O 3	??MgO	Fusing point
						Comparative Examples 1	?48.28	?4.58	?40.94	?1.0	??1400℃
Comparative Examples 2	?48.13	?5.94	?39.89	?1.23	??1400℃
						Comparative Examples 3	?47.02	?4.53	?40.35	?1.67	??1400℃

Claims (2)

1, deoxidation in steel making-wash heat-external refining is self-fluxing nature or part self-fluxing nature slag with effective integrated slag, and this slag system is composed of the following components by weight percentage:

CaO?????????35-75％

SiO ₂???????≤4％

P???????????≤0.04％

Al ₂O ₃?????10-30％

MgO?????????≤6％

S???????????≤0.04％。

2, according to the using method of the described deoxidation in steel making-wash heat of claim 1-external refining with effective integrated slag:

One, add-on is according to the refinery practice of smelting, and steel grades, range of product are joined type, add-on definite the composition:

A, low-carbon (LC), Ultra-low carbon steel grade sheet material: according to steel grade desulfurization requirement, 8-12Kg/t steel;

B, general carbon plate material: according to steel grade desulfurization requirement, 6-16Kg/t steel;

C, high-strength panel: according to steel grade desulfurization requirement, 6-15Kg/t steel;

D, low-carbon (LC) wire rod: according to steel grade desulfurization requirement, 5-18Kg/t steel;

E, cold-heading wire rod: according to steel grade desulfurization requirement, 6-15Kg/t steel;

F, middle carbon, general carbon line material: according to steel grade desulfurization requirement, 4-12Kg/t steel;

G, high-carbon wire rod: according to steel grade desulfurization requirement, 5-10Kg/t steel.

Two, adding method

A, tapping process add ladle with steel stream;

B, tapping begin in the time of 30 seconds to add, and add or once add in batches ladle;

C, tapping added in 2/3～3/4 time.