LF uses initial stage, erode as a result of position of broken bits line serious, steel surrounds service life low, in handling cost, fireproof material was occupied 60.2% , after position of line of steelworks broken bits uses MgO—C brick, raised steel to surround life.
Bag bag line mars steel to basically have reason of the following respects:
(Action of 1) frit corrode. Below high temperature, steel fluid and slaggy diffuse to the middle of including line, produce frit corrode effect. When slaggy with bricky surface contact when, the CaO in broken bits, SiO2 and CaF2 and firebrick happening chemistry react, bricky face is formed slaggy permeate a layer, and matrix is filled up by silicate.
(2) is eroded slaggily. Below high temperature, the CaO of photograph of the fluid in slag and SiO2 a string of 1000 cash along bricky matrix part blowhole, cranny is migratory, to freezing point when, formed the photograph of mine of low melting point that gives priority to with silicate, changed the constituent structure of firebrick, produced degenerative layer, when temperature leap, form a structure to flake.
(3) thermal shock and machinery erode. The electrode when the long agitate that blow argon and three-phase electrode heat is apart from to Bao Bi small, make Bao Bi suffers sharp machine to erode with thermal shock, cause the damage of packet of line.
Below reach by line of broken bits of furnace lid, LF, Bao Bi, bag breathe freely bricky material tries to discuss character.
1 furnace lid is used pouring makings
LF furnace lid is used commonly pouring makings knot and into, of LF furnace lid pouring makings should satisfy the following requirement:
(1) has good high temperature capability, because high temperature of LF fine unit process of cargo bandling and slag splash can cause furnace lid,this is of fireproof material erode;
(2) has good heatproof shake gender and be able to bear or endure flake quality, because LF fine is to those who finish is in below intermittent operation and condition of ceaseless temperature change process,this is.
(3) chooses electric frit corundum and fancy alumina to be main raw material commonly, aluminium acid calcic cement (8 ％ of 4 ％ ～ ) make bond, the 2 oxidation silicon that joins 12 ％ of 8 ％ ～ and alumina exceed small pink to reach a few accretion and efficient the agent that decrease water.
Position of line of 2 broken bits uses fireproof data
LF fine broken bits belongs to department of CaO—SiO2—Al2O3 broken bits, value of CaO ／ SiO2 is great (namely alkalinity is taller) , al2O3 is contained in broken bits, and the arc ray radiation when position of broken bits line suffers electric arc to heat, so position of broken bits line should choose the basic compound perhaps and fireproof material that is able to bear or endure to erode and fight thermal shock, basically have MgO—Cr2O3 brick, MgO—CaO brick, MgO—CaO—C brick and MgO—C brick. Use MgO—C brick commonly at present, the reason of its damage is:
(1) oxidation causes carbon disappear;
(2) is slaggy invade decarburized layer;
(The MgO in 3) slaggy composition and MgO—C brick undertakes reacting making material of low melting point, cause the corrode damage of reaction layer;
(The oxidation of accretion of 4) antirust metal or expand, create constituent deterioration and intermittent operation (hot loop) condition and bring about a structure loose;
(The rupture that intensity of brick of the MgO—C below 5) high temperature is not worth and causes and fall off.
As a result of broken bits line erode, create life of place of brick of broken bits line under life of the brick that include line. To improve life of brick of position of broken bits line, use steel to include filling technology of gush of broken bits line, choose electric frit magnesium and magnesian dolomite namely arenaceous fill for gush advocate raw material, mix with compound salt, cement exceed fine pink to make bond, deserve to coagulate in order to close to agent of agent, plasticizer, agglomeration.
3 packets of walls use fireproof data
Bao Bi uses tall aluminous brick commonly, although traditional tall aluminous brick is able to bear or endure corrode sex is good, but slag is permeated serious, cause a structure to flake, durable sex is not stable, together with slag permeates place systole to produce crackle, cause damage. Wall of bag of ironworks of steel of 8 long narrow flag uses new day iron the MgO—2MgO·SiO2—C brick that adds SiC replaces tall aluminous brick, this kind of brick handles medium corrode caustic situation in LF fine is the surface very smooth, the brick is seamed suffer oxidation frit damage scarcely.
Compare with photograph of tall aluminous brick, the corrode caustic rate that uses MgO—2MgO·SiO2—C brick to include line reduces 30 ％ on average.
The MgO—CaO(do not have carbon that home studies to unit and steelworks combine development is not burned) the brick is used at Bao Bi, rate of average corrode caustic is furnace of 3.17 Mm ／ , clean to production steel is very advantageous at the same time.
Baobi uses MgO—C brick entirely, life comparing rises substantially with other brick. Al2O3—MgO—C brick and Al2O3—C brick were used at Bao Bi to also obtain better result.
Steel bag wall is at present fireproof material develops to indeterminate form from boarding goods, go up character from material see carbon having magnesium, aluminium magnesium carbon, aluminium one pointed spar is pouring makings, material of magnesian calcic department also is development direction. Position of line of broken bits of blame of bag of steel of steel 90 T makes an appointment with 2 M high to use tall aluminium magnesium entirely pouring makings, bao Ling amounts to 90 ～ 98 times, pouring expect to in using a process, did not appear to the structure flakes and stick steel phenomenon. Working line uses pointed spar of the corundum that do not have carbon to pledge prefab piece replace Al2O3—MgO—C brick, make steel surrounds life by rise 65 times on average formerly average 121.
4 packets of bottoms use fireproof data
By the bag, greet steel face to suffer steel fluid to pound the fireproof material of place especially, because heat up a loop to produce crackle, slag to permeate repeatedly, create a structure flake and a juncture place that steel fluid invades concussion brick and bag bottom brick, cause the damage by the bag.
Bottom uses zirconium stone brick commonly or build by laying bricks or stones of tall aluminous brick is built or with the tall calcic magnesium that contains CaO 16 ％ qualitative dry type pounds dozen of makings.
5 packets of bottoms breathe freely brick
The 5.1 development that the brick breathes freely by the bag
20 centuries 50 time are prime, the argon that already began to use an overmuch aperture medium on production enrages agitate steel fluid, but till time metaphase, it is better to appeared breathe freely purify material, this kind of method just is able to popularize. Breathe freely bricky development, basically experienced 3 generation. The feature of front row acting perforated brick depends on it is seam the assembly that reachs composition of mouth of water of a brick, change by blame straight blowhole, annulus. Use this kind of technology and use tall aluminium, magnesian qualitative fireproof data, breathe freely bricky life is only 20—25 furnace second, breathe freely below general requirement namely 300 ～ 400min. This kind breathes freely the brick is used annulus is seamed and bricky combination guides gas and not be fixed passageway, the mutual and shirt-sleeve phenomenon of bubble of meeting occurrence air, shirt-sleeve bleb passes through bath impossibly equably, have the effect that is less than composition of even steel fluid and temperature, special the intermediate zone between steel fluid and broken bits layer, air bubble produces a broken bits likely, those who reduce steel fluid is clean degree. Additional, shirt-sleeve bleb is broken away from breathe freely the speed when bricky surface is reduced apparently, form recoil of so called “ to attack action ” , fully erosive vent plug and all round area water mouth is mixed a bricky) , arise to be marred additionally thereby. Serious erosive meeting makes breathe freely the corrode caustic of occurrence concave side of pottery and porcelain, steel fluid of remain and broken bits in furnace second clearance is met solidify, bring about permeability can undesirable, replace this kind to breathe freely consequently brick already very should.
In front row era breathes freely the 2nd generation that direct aperture appeared after the brick breathes freely brick, it makes inert air current enters bath through deciding diameter passageway. Small bleb can eject enters steel fluid in, the channel that keeps certain at the same time asks be apart from, can avoid air bubble to form. But fall in working requirement, ab extra grain can jam repeatedly passageway, at the same time discontinuous meeting lowers the gas between brick of pottery and porcelain and face of build by laying bricks or stones the pressure inside the passageway, in bringing about steel fluid to answer engulf to enter a passageway, cause breathe freely the effect is exasperate, jam thoroughly eventually.
Surround life to lengthen steel, developed the 3rd generation to breathe freely brick, those who use is whole is touched become oscillatory technology. Use this kind of technology and the combination of brick of leave out bottom appears vent plug, make surround life lengthens the integral bottom that appears vent plug, as a result of,also won't appear again so erosive and in all round area generation is marred prematurely. The 3rd generation breathes freely bricky development is the result that has academic research and test to the line in integral steel bag. Because the 3rd generation breathes freely,the geometrical appearance of bricky passageway becomes rectangular slit, obtain ideal thereby breathe freely dependability, and be in likely furnace second to breathing freely bricky surface is adopted defend measure.
5.2 steel bag breathes freely bricky sort and property
Breathe freely bricky sort basically has dispersion model breathe freely brick, directional stoma breathes freely brick, slit breathe freely brick, labyrinthian model breathe freely the brick.
A dispersion breathe freely brick
Dispersion breathe freely the brick because dispersion breathe freely the stomatic structure that the brick has a lot of to distributing without the rule, accordingly its characteristic is the odd bleb with can arise quite good below low pressure group. When sufferring effect of great pressure gas, standing by exterior place to be able to form a lot of big bleb, as a result of strong retrorse impact, hot corrode is aggravating, corrode caustic is accelerated. Dispersion breathe freely the brick can be permeated because of hole happening, form compact place, intermittent state is included in steel (during maintenance) or when beginning to blow air afresh, breathe freely bricky surface is invaded caustic easily ceaselessly by periodic heat (because air current is passed,attack with recoil) , osmosis (as a result of steel fluid) , solidify action and happen flake. The dispersion that tears open next courses to use breathe freely brick, all have commonly thick the slag that is 20 ～ 30mm permeates a layer. In process of the processing that blow air, slag permeates an area to because gush blows pressure generation to flake,be met, quicken corrode caustic of the brick greatly thereby. Ba Denggang works falls in comparable condition, used the tall aluminium that has not directional air hole and magnesium to breathe freely character the brick reachs those who take directional stoma to breathe freely brick. Of not directional stoma breathe freely bricky life is 10 furnace second, and of directional stoma breathe freely bricky life is 20 furnace, and bricky remains ply is compared former thick much.
B directional stoma breathes freely brick
The channel of small diameter is set in compact firebrick, call ” of “ directional stoma. Breathe freely in directional stoma the gas in the brick passes fluid of a certain quantity of steel of insufflate of a narrow passage providing the only means of access to a certain place that decide way. With dispersion model breathe freely bricky photograph is compared, directional stoma breathes freely the brick is in fireproof stuff place is not flat. Its marked characteristic is to be able to use the fireproof material of as identical as lining brick density to make, can make with more compact material even, this increased to breathe freely high temperature compressive strength of the brick, have bigger fight aggressivity and fight a metal osmotic, lengthened breathe freely bricky service life. The throughput of directional stoma can pass the amount of wool stoma and size to control. Directional stoma breathes freely the brick can generate the bubble with a large number of small diameters group, improve smelt reaction condition, life is dispersion model breathe freely of the brick double or 3 times. Bulk density is more than line brick, be helpful for increasing compression strength. At the same time the choice of material compares production dispersion breathe freely the brick is stricter, join zirconium compound to reduce breathe freely bricky wetability.
C slit breathe freely brick
Slit breathe freely the brick is stay inside compact brick have fine seam, mix in cone of compact pottery and porcelain for example all round set between line, perhaps divide the brick into many component, it is again between these component sandwich iron sheet, in order to increase aperture size and amount. Gas passes the fluid of steel of irregular aperture inbreathe between iron sheet and contented ceramics, slit breathe freely the brick is the same as dispersion model breathe freely the bleb volume of inbreathe of Xiang Gang fluid is larger like the brick. In slit model breathe freely in bricky material, as breathe freely of the brick gradually corrode caustic, after the processing that blow air ends, steel fluid has the risk in immerge aperture.
D is labyrinthian model breathe freely brick
Labyrinthian model breathe freely the brick is integrated the advantage with the sex of safety in operation of alleged perforated brick and long life of brick of compact and fireproof material. Labyrinthian model breathe freely wool stoma net of the brick of by a large number of mutual join position across advocate capillary composition, any capillary by block of infiltration steel fluid when, gas bypasses very easily, lowered gas greatly the loss inside the brick. In addition, because do not have direct aperture, seam reach starting a hole, avalanche danger also is reduced greatly. Labyrinthian model breathe freely net of stoma of wool of area of bricky upside safety is shown annular, place of its bottom key becomes square. Labyrinthian model breathe freely brick and perforated brick photograph are compared, life raised 77 ％ ～ 100 ％ .
5.3 steel bag breathes freely of the brick mar
Breathe freely the brick mars basically have 3 reasons:
(1) steel fluid permeates the inbreathe of gas of the block up in aperture, clear in the gun that use oxygen when bricky surface, oxygen and steel and broken bits are contacted and produce reaction, make firebrick surface flakes, cause breathe freely the brick is destroyed;
(In the process of fluid of steel of 2) gas inbreathe, the bubble that blows kickbacks bricky surface, erode badly bricky substance appearance;
(3) breathes freely brick and the instant that steel fluid contacts, bear the thermal shock of steel fluid is caused flake;
(4) breathes freely the temperature that brick and the exterior temperature that steel fluid contacts are steel fluid, and another surface is room temperature, cause the temperature gradient with bricky larger put oneself in another's position; The use that additionally steel wraps is intermittent operation, frequent cold hot action, make structure of bricky substance appearance is destroyed, erode in what steel fluid reachs air stream next generation flake.
Annals of fireproof data limited company is in furnace of kiln of Zhengzhou Rong Cheng industrial dedicate oneself to the service of one's motherland, industry of service high temperature is oneself, we bear tens of year the technology is accumulated, active and before look up ground is high temperature industry will make tomorrow make brand-newly, become hard " boiler and expert of liner of furnace of hot project kiln " .
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