CN104164536B - The anti-nitrogen pick-up control method of super low nitrogen steel RH treatment unit - Google Patents
The anti-nitrogen pick-up control method of super low nitrogen steel RH treatment unit Download PDFInfo
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- CN104164536B CN104164536B CN201310182738.XA CN201310182738A CN104164536B CN 104164536 B CN104164536 B CN 104164536B CN 201310182738 A CN201310182738 A CN 201310182738A CN 104164536 B CN104164536 B CN 104164536B
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Abstract
Present invention is disclosed a kind of anti-nitrogen pick-up control method of super low nitrogen steel RH treatment unit, comprise: the A.RH treatment unit production phase: resistance to material upper end welding one circle antiseepage right angle steel plate outside soaking tub, steel courage in steel plate one end, antiseepage right angle and resistance to material is connected and fixed, and extend to bottom steel courage with resistance to material bottom maintain an equal level; The treatment stage of B.RH: reduce circulation airshed when process starts, and in the end one-level booster pump completes temperature adjustment before outputing; After in the end one-level booster pump is outputed, improve circulation airshed; In the end one-level booster pump is outputed RH process and is terminated, and controls condition of high vacuum degree≤0.266Kpa, and hold-time >=20min; C. maintenance phase: spray repair maintenance is carried out to the resistance to material surface of soaking tub.The present invention can eliminate the generation of nitrogen pick-up phenomenon in RH treating processes, and by being optimized RH process operator scheme and by the hot maintenance optimization of soaking tub, carrying out more effectively to avoid the generation of nitrogen pick-up phenomenon.
Description
Technical field
The present invention relates to RH technology, more particularly, relate to a kind of anti-nitrogen pick-up control method of super low nitrogen steel RH treatment unit.
Background technology
Nitrogen is mainly present in steel with compound form, and the nitrogen of dissolved state is little.The effect of nitrogen in steel is dual, under certain condition, nitrogen is considered to a kind of important alloying element, often adds steel grade to improve the hardness strength of steel, wear resistance corrosion stability etc. with the method for alloy or infiltration, but nitrogen also has disadvantageous one side in steel, as soft steel, the precipitation due to Fe4N causes timeliness and blue shortness phenomenon, when content exceedes certain limit, in steel, form bubble and loosen, and the plasticity of steel is reduced.Produce with regard to steel grade with regard to refining RH, major part is all soft steel, therefore the latter's harmful effect is particularly outstanding, some special steel grade, as ultra low carbon IF steel requirement of nitrogen is less than 30ppm.Along with variety steel ratio increases, particularly the low nitrogen of high attached value (finished product: [N]≤30ppm) steel grade ratio also obviously rises.But due to the restriction of various factors, during low nitrogen steel super through RH process, often nitrogen pick-up phenomenon occurs, so it is comparatively large to control difficulty, it is more that ultralow nitrogen height retains heat, changes steel amount comparatively large, bring considerable influence to steel-making mass loss and company quality's cost control.
On the other hand, some special steel grade having bound span of control to require to finished product nitrogen, Automated condtrol process is implemented at RH, due to soaking tub poor sealing, there is leakage cause causes RH process automatically to control the unstable of nitrogen, therefore to study the measure of the anti-nitrogen pick-up of soaking tub, be conducive to the stability contorting of low nitrogen steel and middle nitrogen steel.
Because nitrogen solubleness in steel declines with point drops, but far above the solubleness of hydrogen, nitrogen solubility is about 15 times of hydrogen solubleness, therefore under vacuum condition, particularly soaking tub exists if any gas leak phenomenon, molten steel can be easy to nitrogen pick-up phenomenon occurs, and the finished product nitrogen of low nitrogen steel kind can be caused to exceed standard and nitrogen has span of control to require therefore to be necessary the instability that the finished product nitrogen of steel grade controls very much to study the measure preventing soaking tub from leaking gas.
As shown in Figure 1, because the steel courage 3 in the resistance to material 2 of soaking tub 1 is in RH treating processes, molten steel temperature is very high, be generally 1625 degree, expanded by heating between resistance to material 2 and steel courage 3 is caused to create certain gap, the air (in air, nitrogen content reaches more than 70%) of vacuum tank 4 outside just penetrates in the molten steel in ladle 5 (dotted line in Fig. 1) from gap, reacts, finally cause RH that nitrogen pick-up phenomenon occurs in treating processes with molten steel.
Summary of the invention
Object of the present invention aims to provide a kind of anti-nitrogen pick-up control method of super low nitrogen steel RH treatment unit, solves the generation of nitrogen pick-up phenomenon in RH treating processes of the prior art.
On the one hand, a kind of super low nitrogen steel RH treatment unit, comprise vacuum tank and be located at the soaking tub bottom vacuum tank, soaking tub comprises steel courage and is divided into the resistance to material of both sides inside and outside steel courage, resistance to material upper end, described outside is provided with a circle antiseepage right angle steel plate, steel plate one end, antiseepage right angle and steel courage are connected to a fixed, and maintain an equal level bottom described steel courage with bottom resistance to material.
Surrounding the outer wall more than slag line of described soaking tub and upper end are provided with a spray repair layer.
The lower end of described soaking tub is also provided with a spray repair layer.
The thickness of described spray repair layer is 3cm.
On the other hand.An anti-nitrogen pick-up control method for super low nitrogen steel RH treatment unit, specifically comprises the following steps:
A. in the RH treatment unit production phase: in the outside of soaking tub, resistance to material upper end is welded with a circle antiseepage right angle steel plate, and the steel courage in steel plate one end, antiseepage right angle and resistance to material is connected to a fixed, and by extend to bottom steel courage with resistance to material bottom maintain an equal level;
B., RH treatment stage, following rate-determining steps is comprised:
B1. when processing beginning, reduce circulation airshed, and in the end one-level booster pump completes temperature adjustment before outputing;
B2., after in the end one-level booster pump is outputed, circulation airshed is improved;
B3. in the end one-level booster pump is outputed RH process and is terminated, and controls high vacuum≤0.266Kpa, and hold-time >=20min.
C. at maintenance phase, by carrying out spray repair maintenance to the resistance to material surface of soaking tub.
In step bl is determined., described reduction circulation airshed is for adjusting to 1000Nl/min; In step B2, described raising circulation airshed is for adjusting to 2800Nl/min.
Described step C specifically comprises the following steps:
C1. after the first stove washing trough process terminates, overall dross is carried out to soaking tub, and surrounding outer wall more than the slag line of soaking tub and upper-end part of driving carry out even spray repair;
C2. in RH process to mid-term, spray repair is carried out to the lower end of soaking tub, and toasts 6 ~ 12min.
The anti-nitrogen pick-up control method of super low nitrogen steel RH treatment unit of the present invention is welded with a circle antiseepage right angle steel plate by material upper end resistance in the outside of soaking tub, and by extend to bottom steel courage with resistance to material bottom maintain an equal level, thus infiltration of external air can be avoided to enter in molten steel, to eliminate the generation of nitrogen pick-up phenomenon in RH treating processes, and by being optimized RH process operator scheme and by the hot maintenance optimization of soaking tub, carrying out more effectively to avoid the generation of nitrogen pick-up phenomenon.
Accompanying drawing explanation
In the present invention, identical Reference numeral represents identical feature all the time, wherein:
Fig. 1 is the structural representation of the RH treatment unit of prior art;
Fig. 2 is the structural representation of the soaking tub of RH treatment unit of the present invention;
Fig. 3 is the schematic diagram of soaking tub spray repair position of the present invention.
Embodiment
Technical scheme of the present invention is further illustrated below in conjunction with drawings and Examples.
Refer to shown in Fig. 2, super low nitrogen steel RH treatment unit of the present invention is substantially identical with prior art, and equally also comprise vacuum tank and be located at the soaking tub 1 bottom vacuum tank, soaking tub 1 comprises steel courage 3 and is divided into the resistance to material 2 of both sides inside and outside steel courage 3.Unlike, a circle antiseepage right angle steel plate 6 is provided with in resistance to material 2 upper end, described outside, steel plate 6 one end, antiseepage right angle and steel courage 3 connect fixing by being weldingly connected, open completely isolated for the air of the gap produced during steel courage 3 expanded by heating and vacuum tank outside, and by extend to bottom steel courage 3 with resistance to material 2 bottom maintain an equal level, to stop air to enter molten steel, thus effectively prevent infiltration of external air and enter molten steel, eliminate the generation of nitrogen pick-up phenomenon in RH treating processes.Shown in Fig. 3, in addition, the surrounding outer wall of the slag line more than 7 of described soaking tub 1 and upper end are provided with a spray repair layer, and the lower end of described soaking tub 1 is also provided with a spray repair layer (arrow A in figure, B are expressed as the position of required spray repair), and the thickness of described spray repair layer is 3cm.
13109-1
The anti-nitrogen pick-up control method of super low nitrogen steel RH treatment unit of the present invention specifically comprises the following steps:
A. in the RH treatment unit production phase: be welded with a circle antiseepage right angle steel plate 6 in resistance to material 2 upper end, the outside of soaking tub 1, and the steel courage 3 in steel plate 6 one end, antiseepage right angle and resistance to material 2 is connected to a fixed, and by extend to bottom steel courage 3 with resistance to material 2 bottom maintain an equal level;
B., RH treatment stage, following rate-determining steps is comprised:
B1. when processing beginning, reduce circulation airshed, and in the end one-level booster pump completes temperature adjustment (being unfavorable for denitrogenation because temperature is high) before outputing, and described reduction circulation airshed is for adjusting to 1000Nl/min, and in prior art, it is 2000Nl/min that process starts circulation airshed.
B2. after in the end one-level booster pump is outputed, improve circulation airshed, described raising circulation airshed is for adjusting to 2800Nl/min, advantage so is under larger circulation Ar airshed, due to turbulent flow, a large amount of nuclei of bubbles is produced instantaneously in upcast, gas in molten steel is gradually to Ar bubble internal diffusion, bubble is under high temperature, low pressure effect, volume becomes hundred times of ground to increase, so that molten steel goes to the spray of vacuum chamber overhead as fountain, molten steel is sprayed into raindrop shape, degassed surface-area is increased greatly, thus accelerates denitrification rates.
B3. according to the specific rule in Xihua, along with the reduction of nitrogen partial pressure, more denitrogenation is conducive to.Therefore, in the end one-level booster pump is outputed RH process and is terminated, and controls high vacuum≤0.266Kpa, and hold-time >=20min, and in existing operator scheme high vacuum hold-time >=12min.
C. at maintenance phase, by carrying out spray repair maintenance to resistance to material 2 surface of soaking tub 1, specifically comprise the following steps:
C1. after the first stove washing trough process terminates; overall dross (the main chemical compositions Al2O3 in slag, SiO2 etc. have provide protection to the resistance to material 2 of soaking tub 1) is carried out to soaking tub 1; and carry out even spray repair at the surrounding outer wall of the slag line more than 7 of soaking tub 1 and upper-end part of driving; the main chemical compositions of Gunning refractory is MgO, CaO, H2O; spray repair is wanted evenly; do not stay dead angle, spray repair gauge control is at 3cm.
C2. start to mid-term in RH process, the lower end of soaking tub 1 is owing to being immersed in molten steel for a long time, comparatively large to the melting loss of resistance to material 2, be easy to produce crack, so spray repair maintenance will will be carried out to the lower end of soaking tub 1, spray repair is also wanted evenly, the lower end of soaking tub 1 is made not have crack, once have crack to produce will carry out powerful spray repair, and after spray repair, carry out short period of time baking 6 ~ 12min, make Gunning refractory have sufficient sintering time.
Super low nitrogen steel RH treatment unit of the present invention and anti-nitrogen pick-up control method thereof is adopted to try out, try out and within latter 6 months, have a competition with first 6 months, nitrogen height retains minimizing 12 stove, obtain control nitrogen effect very well, and nitrogen height retains by average 500 yuan/ton of costing bio disturbance, average furnace output 293 tons, then adopt stove × 2 × 293, year benefit=12 after the present invention ton/stove × 500 yuan/ton=351.6 ten thousand yuan, benefit is very remarkable.
Those of ordinary skill in the art will be appreciated that, above specification sheets is only one or more embodiments in the numerous embodiment of the present invention, and not uses limitation of the invention.Any equalization for the above embodiment changes, modification and the equivalent technical scheme such as to substitute, as long as spirit according to the invention, all will drop in scope that claims of the present invention protect.
Claims (3)
1. an anti-nitrogen pick-up control method for super low nitrogen steel RH treatment unit, is characterized in that:
Specifically comprise the following steps:
A. in the RH treatment unit production phase: in the outside of soaking tub, resistance to material upper end is welded with a circle antiseepage right angle steel plate, and the steel courage in steel plate one end, antiseepage right angle and resistance to material is connected to a fixed, and by extend to bottom steel courage with resistance to material bottom maintain an equal level;
B., RH treatment stage, following rate-determining steps is comprised:
B1. when processing beginning, reduce circulation airshed, and in the end one-level booster pump completes temperature adjustment before outputing;
B2., after in the end one-level booster pump is outputed, circulation airshed is improved;
B3. in the end one-level booster pump is outputed RH process and is terminated, and controls condition of high vacuum degree≤0.266Kpa, and hold-time >=20min;
C. at maintenance phase, by carrying out spray repair maintenance to the resistance to material surface of soaking tub.
2. the anti-nitrogen pick-up control method of super low nitrogen steel RH treatment unit as claimed in claim 1, is characterized in that:
In step bl is determined., described reduction circulation airshed is for adjusting to 1000Nl/min; In step B2, described raising circulation airshed is for adjusting to 2800Nl/min.
3. the anti-nitrogen pick-up control method of super low nitrogen steel RH treatment unit as claimed in claim 1, is characterized in that:
Described step C specifically comprises the following steps:
C1. after the first stove washing trough process terminates, overall dross is carried out to soaking tub, and surrounding outer wall more than the slag line of soaking tub and upper-end part of driving carry out even spray repair;
C2. in RH process to mid-term, spray repair is carried out to the lower end of soaking tub, and toasts 6 ~ 12min.
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| CN200958112Y (en) * | 2006-10-08 | 2007-10-10 | 上海宝钢冶金技术服务有限公司 | Infusion pipe for vacuum degassing apparatus |
| CN101748246A (en) * | 2008-12-15 | 2010-06-23 | 鞍钢股份有限公司 | Method for improving service life of insert tube of vacuum degassing furnace |
| CN201525862U (en) * | 2009-11-20 | 2010-07-14 | 武汉钢铁(集团)公司 | Novel insert tube for RH vacuum device |
| CN201548054U (en) * | 2009-11-11 | 2010-08-11 | 新疆八一钢铁股份有限公司 | Casing patch cylinder for dip pipe of refining furnace |
| CN202047089U (en) * | 2011-03-28 | 2011-11-23 | 中国重型机械研究院有限公司 | Vacuum degree adjusting device for water steam jet pump |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0751821A (en) * | 1993-08-16 | 1995-02-28 | Tokyo Yogyo Co Ltd | Immersed pipe for vacuum degassing apparatus |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN200958112Y (en) * | 2006-10-08 | 2007-10-10 | 上海宝钢冶金技术服务有限公司 | Infusion pipe for vacuum degassing apparatus |
| CN101748246A (en) * | 2008-12-15 | 2010-06-23 | 鞍钢股份有限公司 | Method for improving service life of insert tube of vacuum degassing furnace |
| CN201548054U (en) * | 2009-11-11 | 2010-08-11 | 新疆八一钢铁股份有限公司 | Casing patch cylinder for dip pipe of refining furnace |
| CN201525862U (en) * | 2009-11-20 | 2010-07-14 | 武汉钢铁(集团)公司 | Novel insert tube for RH vacuum device |
| CN202047089U (en) * | 2011-03-28 | 2011-11-23 | 中国重型机械研究院有限公司 | Vacuum degree adjusting device for water steam jet pump |
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