CN105642849A - Crystallizer casting powder for continuous casting of titanium-containing steel - Google Patents

Abstract

The invention provides crystallizer casting powder for continuous casting of titanium-containing steel. The casting powder comprises, by weight, 5-35% of CaO1, 7-15% of SiO2, 10-30% of Al2O3, 3-15% of F-, 3-10% of Li2O, 5-20% of BaO5, 5-20% of Mn2O3, 2-12% of C, MgO with the amount smaller than or equal to 1.5% and Fe2O3 with the amount smaller than or equal to 2%. The melting point of the casting powder for continuous casting ranges from 960 DEG C to 1200 DEG C and 1300 DEG C, and viscosity ranges from 0.08 Pa.s to 0.18 Pa.s. Compared with a traditional slag system, the content of SiO2 is lower, and the content of Al2O3 is higher. Meanwhile, a certain amount of Mn2O3 is matched to serve as a strong oxidant, harm of interface solid coagulation of steel slag in a crystallizer in the continuous casting process of the titanium-containing steel is effectively eliminated or relieved, relative stability of performance of the casting powder is maintained, the number of continuous casting is increased, surface quality of casting blanks is improved, and the surface coping amount of the casting blanks is reduced.

Description

Ti-containing steel crystallizer protecting cinder for continuous casting

Technical field

The invention belongs to continuous crystallizer protecting slag technical field, be specifically related to Ti-containing steel crystallizer protecting cinder for continuous casting.

Background technology

In titaniferous casting cycle, due to aluminum, titanium, nitrogen content height in molten steel, substantial amounts of TiN can be precipitated out under cast temperature and float up to slag interface, with the SiO of component in covering slag₂Etc. reacting; in slag, component is reacted make slag system basicity raise with [Al], [Ti] in molten steel simultaneously; produce the high-melting-point substances such as perovskite and slag is wrapped up in and mixed; in crystallizer, slag interface forms solid condensate; cause the change of covering slag composition and performance; also hindering the normal supply of covering slag melt cinder, these factors all easily cause bleed-out, slag inclusion and other problem such as casting billet surface and surface defect, affect continuous casting direct motion.

Traditional Ti-containing steel crystallizer protecting residue is mainly by CaO and SiO₂Composition, in addition in order to regulate viscosity and the solidification temperature of liquid slag, can add Al₂O₃��MgO��Na₂O, F and Li₂O etc., additionally the burn-off rate for adjusting slag also can add C etc.

Covering slag increases Al₂O₃And TiO₂Component, can reduce slag steel to a certain extent and react the adverse effect brought. Such as, Chinese patent 201410710112.6 disclosed " a kind of new type corrosion resistant alloy steel continuous casting covering slag and application thereof ", being technically characterized in that of this invention, the percentage by weight of its composition is: CaO:17% ~ 25%, SiO₂: 23% ~ 31% and CaO/SiO₂=0.7 ~ 0.9, Al₂O₃: 10% ~ 14%, MgO:1 ~ 4%, flux: Na₂O+Li₂O:10% ~ 15%, B₂O₃: 1% ~ 8%, TiO₂: 1% ~ 6%, BaO:4% ~ 8%, F:10% ~ 13%. This invention increases Al in right amount₂O₃And TiO₂Component, reduces slag steel reactive, stabilizes covering slag composition, thus covering slag physicochemical property controls in rational scope. But, SiO in this invention covering slag₂Content is still higher, Al₂O₃And TiO₂Content is less, reduces slag-metal reaction DeGrain. It addition, Na in this invention₂O content is higher, still can react with the aluminum in molten steel, titanium, thus fusibleness energy etc. is adversely affected, and Na₂O with the uneven precipitation of Na-Al-O crystal, can affect the strand heat transfer to crystallizer.

Covering slag adds appropriate Fe₂O₃As strong oxidizer, it is possible to weaken SiO₂Reactive with Al, Ti in steel. Chinese patent 200710193114.2 disclosed " continuous casting crystallizer casting powder special for bar plate stainless steel containing titanium and production technology thereof ", Fe in this invention covering slag₂O₃Content is��3%, by adding a certain amount of Fe₂O₃Can effectively weaken SiO₂Reactive with Al, Ti in steel, it is possible to be effectively reduced surface defect of bloom, produce direct motion high, but allocate oxidant Fe into₂O₃React with the TiN floating up to slag interface: (Fe₂O₃)+[TiN]=[Fe]+(TiO₂), the ferrum simple substance of generation is mixed to be rolled in slag and provides advantage for generation " knot fish " (i.e. slag interface solid condensate in crystallizer), and covering slag viscosity increases, and worsens covering slag greasy property, easily causes slag and be unfavorable for that slag steel separates.

Summary of the invention

For prior art above shortcomings; the technical problem to be solved is: how to provide Ti-containing steel crystallizer protecting cinder for continuous casting; in order to alleviate the harm of slag interface solid condensate in crystallizer, and have the advantages that to be able to maintain that casting sequence, raising cc billet surface quality and minimizing casting billet surface reconditioning quality are stablized, improved to covering slag performance relatively.

In order to solve above-mentioned technical problem, the present invention adopts the following technical scheme that Ti-containing steel crystallizer protecting cinder for continuous casting, including the component of following wt%: CaO15 ~ 35%, SiO₂7~15%��Al₂O₃10~30%��F^-3~15%��Li₂O3~10%��BaO5~20%��Mn₂O₃5 ~ 20%, C2 ~ 12%, MgO��1.5% and Fe₂O₃��2%��

Further, described CaO and SiO₂Mass ratio be 1 ~ 3.2:1.

Further, when being applied to the steel grade of Ti=0.9%, Al=0.1%, the component of described covering slag also includes B₂O₃��4%��

Compared to existing technology, there is advantages that

1, the present invention is directed to the character easily reacted with covering slag in Ti-containing steel (particularly the Ti-containing steel of mass content >=0.3% of titanium) containing the active element such as aluminum and titanium; composition and the proportioning of covering slag of the present invention is gone out by creationary research design; the present invention is using carbon as skeleton, by adding SiO₂7~15%��Al₂O₃13 ~ 30%, effectively reduce or inhibit SiO₂Reacting with the ripple element alive such as Al, Ti in molten steel, collaborative compatibility allocates strong oxidizer Mn into₂O₃5 ~ 20%, reduce SiO further₂And reactive between molten steel, react with the TiN floating up to slag interface simultaneously, generate low price Mn oxide and the TiO that can be dissolved in slag₂, TiN dissolubility in oxidizing slag is relatively low, it is not easy to occurs wrapping up in mixed, makes covering slag performance not easily be degraded; Covering slag of the present invention is also composite BaO5 ~ 20%, improves the glass performance of covering slag, is conducive to improving the lubricity of covering slag and absorbing Al₂O₃��TiO₂Etc. the stability being mingled with rear performance; Present component adopts Li₂O3 ~ 10% replaces Na₂O is as flux, and is aided with C2 ~ 12%, by the collaborative compatibility effect between composition, has played effect of better fluxing, has regulated the burn-off rate of covering slag, it is possible to maintain covering slag performance relatively stable.

2, the present invention is further at SiO₂Slag Acidity of Aikalinity can be coordinated when content is relatively low, and improve covering slag lubricity, composite B in covering slag₂O₃, and find B by studying₂O₃Content more than 5% time can react with Al in molten steel, B the most at last₂O₃Content controls, in��4% scope, to achieve good coordination and improve effect.

3, the more traditional Ti-containing steel protection slag system SiO of covering slag of the present invention₂Content is relatively low, Al₂O₃Content is higher, allocates appropriate Mn into simultaneously₂O₃As strong oxidizer, weaken SiO₂And reactive between molten steel, effectively alleviate the harm of slag interface solid condensate in crystallizer; Experiment proves that the fusing point of covering slag of the present invention is up to 960 ~ 1200 DEG C, 1300 DEG C of viscosity 0.08 ~ 0.18Pa.s, more general covering slag viscosity is less, and the reduction of viscosity can make covering slag have good lubrication in crystallizer, reduces TiN, TiO in casting process₂Cause slag viscosity to improve Deng entering in slag, effectively prevent slag and wrap up in and mix and in crystallizer, slag interface solid condensate occurs in a large number.

4, crystallizer protecting residue of the present invention is used in the continuous casting production of Ti-containing steel; result is shown in casting cycle in crystallizer slag interface and solid condensate does not occur; it is effectively ensured continuous casting direct motion; cc billet surface quality and subcutaneous quality are good; casting billet surface reconditioning quality reduces, and achieves the technique effect of excellence.

Detailed description of the invention

Below in conjunction with specific embodiment, Ti-containing steel crystallizer protecting cinder for continuous casting of the present invention is described in further detail.

Ti-containing steel crystallizer protecting cinder for continuous casting, including the component of following wt%: CaO15 ~ 35%, SiO₂7~15%��Al₂O₃10~30%��F^-3~15%��Li₂O3~10%��BaO5~20%��Mn₂O₃5 ~ 20%, C2 ~ 12%, MgO��1.5% and Fe₂O₃�� 2%. And CaO and SiO₂Mass ratio be 1 ~ 3.2:1. For the steel grade of Ti=0.9%, Al=0.1%, also include B₂O₃��4%��

The preparation method of above-mentioned Ti-containing steel crystallizer protecting cinder for continuous casting, comprises the steps:

1) using fluorite, calcite, clinker, brium carbonate, quartz sand, sintered bauxite, lithium carbonate, boric anhydride, manganese sesquioxide managnic oxide and carbonaceous material as raw material, constituent mass percentage composition according to described covering slag, calculate described each raw-material consumption, and weigh each raw material according to the consumption calculated;

2) fluorite, calcite, clinker, brium carbonate, quartz sand, sintered bauxite, lithium carbonate and boric anhydride mixing step 1) weighed, put in mineral hot furnace 1350 DEG C of-1450 DEG C of inside holding 30 ~ 40 minutes, make the fusing of each raw material uniformly, natural cooling of coming out of the stove subsequently, obtain pre-melt;

3) to step 2) the pre-melt that obtains carries out pulverizing and jevigating, after making levigate fritting material granularity��0.074 ��m, adds the Mn that step 1) weighs₂O₃And carbonaceous material, obtain siccative;

4) siccative, water and cellulose binder step 3) obtained is put in refiner and is refined 30-60 minute, makes slip; Wherein, the weight ratio of described siccative, water and cellulose binder is 1:0.8 ~ 1.2:1.6 ~ 2;

5) slurry step 4) obtained is sent into spraying granule drying tower inner drying and is granulated, and prepares described crystallizer protecting residue.

Described each raw-material chemical composition percentage by weight is as follows respectively:

Fluorite: CaF₂>=90%, SiO₂�� 6.0%, S��0.05%,

Calcite: CaO50-55%, Al₂O₃�� 0.5%, MgO��2.5%, Fe₂O₃�� 0.5%, SiO₂�� 1%,

Clinker: CaO62-68%, SiO₂20-25%, Al₂O₃�� 6%, MgO��3%, Fe₂O₃�� 5%,

Brium carbonate: BaCO₃>=95%,

Quartz sand: SiO₂>=95%,

Sintered bauxite: Al₂O₃>=80%, SiO₂�� 8%, MgO��2.5%, Fe₂O₃�� 3%,

Lithium carbonate: Li₂CO₃>=98%,

Boric anhydride: B₂O₃>=95%,

Manganese sesquioxide managnic oxide: Mn₂O₃>=95%,

Carbonaceous material: C >=95%.

Moisture��0.5% in the described crystallizer protecting residue prepared, granularity is at 0.01 ~ 1.0mm.

Described carbonaceous material is white carbon black and/or graphite.

Giving 4 specific embodiments in table 1 below, the component of 4 embodiment covering slags and the important physicochemical property of correspondence thereof are specifically as shown in table 1.

The composition of table 1 covering slag and main physical and chemical

By upper table 1 it can be seen that 1300 DEG C of viscositys of crystallizer protecting residue of the present invention are low, it is possible to make this covering slag have good lubrication in crystallizer. By embodiment in upper table 1 1. 2. number slag be applied to the steel grade of Ti=0.9%, Al=0.1%, 3. 4. number slag is applied to the steel grade of Ti=0.3%, Al=0.035%; Pulling rate is 1.2m/min, and result shows: 1. 2. number slag in casting cycle in crystallizer slag interface solid condensate significantly reduce, casting sequence >=3; 3. 4. number slag in casting cycle in crystallizer slag interface solid condensate does not occur, be effectively ensured continuous casting direct motion, cc billet surface quality and subcutaneous quality good, the more existing covering slag of casting billet surface reconditioning quality reduces more than 50%.

The above embodiment of the present invention is only for example of the present invention is described, and is not the restriction to embodiments of the present invention. For those of ordinary skill in the field, other multi-form change and variations can also be made on the basis of the above description. Every belong to apparent change that technical scheme amplified out or the variation row still in protection scope of the present invention.

Claims (5)

1. Ti-containing steel crystallizer protecting cinder for continuous casting, it is characterised in that include the component of following wt%: CaO15 ~ 35%, SiO₂7~15%��Al₂O₃10~30%��F^-3~15%��Li₂O3~10%��BaO5~20%��Mn₂O₃5 ~ 20%, C2 ~ 12%, MgO��1.5% and Fe₂O₃��2%��

2. Ti-containing steel crystallizer protecting cinder for continuous casting according to claim 1, it is characterised in that described CaO and SiO₂Mass ratio be 1 ~ 3.2:1.

3. Ti-containing steel crystallizer protecting cinder for continuous casting according to claim 1, it is characterised in that when being applied to the steel grade of Ti=0.3%, Al=0.035%, the wt% component of crystallizer protecting residue is: CaO28.06%, SiO₂14.13%��Al₂O₃10.29%��F^-8.68%��Li₂O4.3%��BaO19.27%��Mn₂O₃11.69%, C2.42%, MgO0.5% and Fe₂O₃0.66%��

4. Ti-containing steel crystallizer protecting cinder for continuous casting according to claim 1, it is characterised in that when being applied to the steel grade of Ti=0.9%, Al=0.1%, the component of described covering slag also includes B₂O₃��4%��

5. Ti-containing steel crystallizer protecting cinder for continuous casting according to claim 4, it is characterised in that when being applied to the steel grade of Ti=0.9%, Al=0.1%, the component of the wt% of crystallizer protecting residue is: CaO15.56%, SiO₂7.45%��Al₂O₃13.4%��F^-13.57%��Li₂O3.84%��BaO19.45%��Mn₂O₃19.59%��C2.48%��MgO1.46%��Fe₂O₃0.42% and B₂O₃2.78%��