CN1040659C - High effective oxygen blowing method for making steel in converter - Google Patents

Abstract

The present invention mainly relates to an oxygen-blowing method for smelting steel in a converter, which belongs to the field of smelting steel. The present invention is mainly characterized in that during smelting steel in an oxygen top blowing converter, blowing parameters of a nozzle of an oxygen lance need replacing in time, such as ferric oxide content in final slag, jet-core region speed of oxygen, effective areas, oxygen flow coefficients, the erosion depth of the spraying nozzle, etc. After the nozzle of the oxygen lance is used for certain times, when the jet flow characteristics and the metallurgical effects start decreasing, the jet flow characteristics and the metallurgical effects are kept in a favorable state by adjusting the position of the oxygen lance, the oxygen pressure and the oxygen flow, increasing fluxing agents, etc. The nozzle of the oxygen lance can be reasonably used by using the method, the achievement is reduced, and the technical economical indexes are enhanced.

Description

Converter steelmaking oxygen blast control method

The invention belongs to field of steel-making.Mainly be applicable to the oxygen blown control of converter steelmaking.

In top-blown converter steelmaking, the oxygen rifle is one of key equipment.The effect of oxygen rifle is that the pressure with oxygen can be converted into kinetic energy, forms Mach in the oxygen lance blow head exit and be 1.7～2.2 high-speed oxygen jet.This high speed oxygen jet produces certain penetration depth to metal pool.It mainly acts on is to supply with the required oxygen of steel-making, agitation molten pool.Carbon in oxygen and the molten bath and other impurity generation oxidizing reaction reach decarburization and remove phosphorus, sulphur impurity, the purpose of cleaning molten steel; Simultaneously, oxygen jet also has impact capacity to metal pool and slag, makes the molten bath produce convection current, reaches the effect of heat transfer and accelerating impurity come-up.So the structure properties of oxygen lance blow head directly influences quality, raw material consumption and the cost of steel.

The geometrical dimension parameter of oxygen lance blow head is the principal element that influences oxygen rifle jet characteristics, has only the spray orifice geometrical dimension of oxygen lance blow head to keep original design parameter, and good oxygen jet quality just can be arranged.But along with the increase of smelting furnace number, oxygen lance blow head all will produce erosion in various degree, makes the geometrical dimension off-design value of spray orifice, thereby causes oxygen rifle jet characteristics to degenerate.Shower nozzle is etched serious more, and it is far away more that its jet characteristics departs from new shower nozzle, and is also serious more to smelting the adverse consequences that produces.Its velocity of discharge that mainly shows oxygen jet descends, and impact area and conversion zone reduce etc., causing slag difficulty, and the splash aggravation, the finishing slag ferric oxide raises, the decline of dephosphorization and desulfurization effect, the excessive and blow end point hit rate of iron loss is low etc.Therefore, when the oxygen jet characteristic, when the characteristic that promptly blows does not reach smelting requirements, in time adjust the oxygen blast parameter, it is rational in time changing oxygen lance blow head.

In this case, the variation of oxygen lance blow head spray orifice geometrical dimension and oxygen jet and significant in the research use to the influence of metallurgical effect.

Jet characteristics to new oxygen lance blow head in the prior art had many researchs, but influence did not also appear in the newspapers for the erosion of shower nozzle in the use and to effusive.

The object of the present invention is to provide a kind of converter steelmaking oxygen blast control method,, perhaps adjust oxygen lance spraying and blow parameter, make good jet characteristics and the excellent metallurgical effect of oxygen rifle protection so that in top-blown converter steelmaking, in time change oxygen lance blow head.

According to above-mentioned purpose, the present invention has adopted following technical scheme:

(1) after oxygen lance blow head use 100 times, every increase by 50 stoves need raising work oxygen pressure 0.07-0.1Mpa;

(2) when the oxygen lance blow head depth of erosion strengthens, reduce the oxygen lance position height, making oxygen jet is 0.25-0.35% to the ratio of the penetration depth in molten bath and pool depth;

(3) when the oxygen flow factor alpha of oxygen lance blow head is lower than 0.95 or when oxygen lance blow head when the spray orifice axis direction is etched the degree of depth and surpasses 8mm, need in time to change oxygen lance blow head.

Now be described further with regard to technique scheme

After oxygen lance blow head uses certain heat, the oxygen jet characteristic begins to worsen, and causes the metallurgic product quality to begin to descend, and production cost increases, the present invention can keep the good oxygen jet and the effect in molten bath by adjusting the oxygen supply parameter, reaches the excellent metallurgical effect.After oxygen lance blow head uses certain number of times, increase the oxygen pressure of oxygen rifle, when oxygen lance blow head is etched certain depth, suitably reduce the oxygen lance blow head position, so just can keep required oxygen jet central speed and to the penetration depth of the necessity in molten bath.Just can keep reacting dynamics condition between the good stirring in molten bath and good steel-slag, and good reaction between carbon and oxygen, make it to reach the metallurgical effect of expection.

Usually oxygen lance blow head is for the casting product, and under the working conditions of rapid heat cycle, the aditus laryngis of shower nozzle shrinks, and promptly diameter diminishes, so oxygen flow reduces, has so just reduced smelting speed, the steel-making time lengthening, and converter productivity descends.When oxygen flow drops to a certain degree, can have a strong impact on the blowing effect, particularly when oxygen flow factor alpha＜0.95, more obvious, at this moment need in time to adopt relative measures, as the oxygen lance blow head that more renews.

In addition, the end face of the vertical spray orifice axis direction of oxygen lance blow head is etched, and causes the Oxygen Flow characteristic of stock to worsen, oxygen gas flow rate decay is too fast, and surging force reduces, and the penetration depth in molten bath is also reduced, impact area reduces, it is bad to change slag, and ferric oxide also raises in the slag, and the present invention is through facts have proved in a large number, when the spray nozzle end face is etched the degree of depth above 8mm, will severe exacerbation the blowing effect, at this moment, the oxygen lance blow head that need more renew.

The present invention adopts effusive pressure and the velocity distribution of being measured different positions, different distance, different angles by micro-processor controlled multiple spot rapid pressure scanning valve system and device, adopts sonar to measure oxygen lance blow head position and monitoringization slag situation in the steelmaking process.

Compared with prior art, the present invention has following advantage:

(1), can be at the nozzle parameter of concrete converter steelmaking condition and the new shower nozzle of oxygen rifle, reasonably make the standard of changing shower nozzle, in time change shower nozzle, reach the existing higher shower nozzle life-span, can keep the excellent metallurgical effect again.

(2), guaranteeing under the prerequisite of good metallurgical effect, by adjusting the oxygen supply parameter, make oxygen jet characteristic and jet and molten bath act on the better scope that all remains on.Bring into play the potentiality of shower nozzle as much as possible, improve shower nozzle work-ing life, reach better technico-economical comparison.

(3), the difference by measuring new and old oxygen lance blow head jet characteristics with contrast different metallurgical effects new, old oxygen lance blow head, make the worker of steel-making recognize that fully the shower nozzle steel-making that use is excessively deteriorated is very uneconomic, the shower nozzle life-span is not that the longer the better, but there is a rational work-ing life, thereby reasonably use oxygen lance blow head, reduce cost and develop skill and economic benefit.

Embodiment

Adopt method of the present invention, old shower nozzle blowing plain carbon stool test after having carried out two groups of new shower nozzles on 30 tons the top-blown oxygen converter and having used certain heat.One group is the injection parameter condition test that oxygen lance blow head need be changed, and its result is as shown in table 1; One group is after old shower nozzle uses certain heat, penetrates parameter by adjusting oxygen lance spraying, still protects the effect in good jet and molten bath and the test of metallurgical effect, and its result is shown in table 2, table 3.

Find out that by table 1 after oxygen lance blow head (being oxygen rifle rifle age) used more than 200 times, compare with new shower nozzle: (1) oxygen consumption increased greatly.Like this, cost rises, and oxygen blow duration is long, and production efficiency is low; (2) the lime consumption is big, and the quantity of slag is big, and the heat of consumption rises, and iron loss increases, and cost also rises; (3) finishing slag iron oxide content height, iron loss increases, and lining erosion is serious or corrode quickening, and lining life is descended.So in this case, it is irrational still continuing to use old shower nozzle, needs in time to change shower nozzle.

Find out that by table 2 and table 3 contrast oxygen lance blow head is compared with new shower nozzle after using more than 100 times, oxygen consumption, finishing slag iron oxide content all increase, but also do not reach unreasonable degree.On this basis, in time adjust the oxygen supply parameter, as shown in table 3, reduce oxygen lance position height (distance between shower nozzle and the static molten steel face) and improve oxygen pressure, just can improve jet characteristics and metallurgical effect greatly, increase as oxygen flow, oxygen consumption and lime consumption reduce, and particularly the finishing slag iron oxide content descends.That is to say,, can produce a desired effect by adjusting the oxygen supply parameter.

The injection parameter condition test data that table 1 oxygen lance blow head need be changed

Nozzle type	Oxygen rifle rifle is inferior age	Oxygen lance position height m	Oxygen pressure MPa	Oxygen flow Nm 3/min	Jet-core region speed m/sec	Jet useful effect radius cm	Shower nozzle depth of erosion mm	Finishing slag iron oxide content (TFe) %	Iron scale add-on Kg/t steel	Lime consumption amount Kg/t steel	Oxygen consumption Nm 2/ t steel
												New shower nozzle	10	1.18	1.00	104.0	198	45	0	12.18	5	70.76	44.85
11	1.18	1.00	104.0	198	45	0	13.71	9	70.12	44.72
											Old shower nozzle		213	0.90	1.16	111.6	145	30	9.8	18.25	10	75.39	48.35
214	0.90	1.16	111.6	145	30	9.8	16.97	9	76.04	48.28
												215	0.90	1.17	112.6	145	30	9.8	15.04	9	75.11	48.54
216	0.90	1.16	111.6	145	30	9.8	21.59	10	74.95	48.44

Table 2 oxygen lance spraying blows the injection parameter data before the parameter adjustment

Nozzle type	Oxygen rifle rifle is inferior age	Oxygen lance position height m	Oxygen pressure MPa	Oxygen flow Nm 3/min	Jet-core region speed m/sec	Jet useful effect radius cm	Shower nozzle depth of erosion mm	Finishing slag iron oxide content (TFe) %	Iron scale add-on Kg/t steel	Lime consumption amount Kg/t steel	Oxygen consumption Nm 2/ t steel
												New shower nozzle	12	1.18	1.00	104.66	198	45	0	13.14	5	70.52	44.86
121	1.12	1.06	105.66	176	36	5.2	15.18	5	73.58	47.82
											Old shower nozzle		122	1.10	1.05	104.86	176	36	5.2	15.20	5	73.92	47.28
123	1.12	1.06	105.66	176	36	5.2	15.10	5	74.01	47.64
												124	1.11	1.06	105.66	176	36	5.2	15.94	5	74.12	47.38
125	1.10	1.05	104.66	176	36	5.2	14.20	5	74.11	47.35

The oxygen lance spraying that table 3 is adjusted after the oxygen supply parameter blows supplemental characteristic

Nozzle type	Oxygen rifle rifle is inferior age	Oxygen lance position height m	Oxygen pressure MPa	Oxygen flow Nm 3/min	Jet-core region speed m/sec	Jet useful effect radius cm	Shower nozzle depth of erosion mm	Finishing slag iron oxide content (TFe) %	Iron scale add-on Kg/t steel	Lime consumption amount Kg/t steel	Oxygen consumption Nm 3/ t steel	Remarks
													New shower nozzle	13	1.18	1.00	104.00	198	45	0	12.52	5	70.58	44.83
126	1.04	1.10	109.64	185	38	5.2	13.25	7	72.95	46.16	Adjust rifle position height and oxygen pressure
												Old shower nozzle		127	1.03	1.10	109.64	185	38	5.2	11.63	7	72.88	46.20	Adjust rifle position height and oxygen pressure
128	1.05	1.11	110.64	187	38	5.2	13.92	8	73.01	46.53	Adjust rifle position height and iron scale
													129	1.03	1.11	110.64	189	39	5.2	12.62	7	73.10	46.63	Adjust rifle position height and oxygen pressure
130	1.05	1.10	109.64	183	37	5.2	13.60	7	72.92	46.22	Adjust rifle position height and oxygen flow

Claims (1)

1, a kind of converter steelmaking oxygen blast control method is characterized in that:

(1) after oxygen lance blow head use 100 times, every increase by 50 stoves need raising work oxygen pressure 0.07-0.1Mpa;

(2) when the oxygen lance blow head depth of erosion strengthens, reduce the oxygen lance position height, making oxygen jet is 0.25-0.35% to the ratio of the penetration depth in molten bath and pool depth;

(3) when the oxygen flow factor alpha of oxygen lance blow head is lower than 0.95 or when oxygen lance blow head when the spray orifice axis direction is etched the degree of depth and surpasses 8mm, need in time to change oxygen lance blow head.