Current, outside including fine except steel, how to produce the fine effect of intermediate bag, improve casting base quality further, should cause from the following respect take seriously:
(The steel inside the bag sheds configuration among 1) . The feature of going from place to place of the molten steel inside intermediate bag has very big effect to eliminating field trash of metal of molten steel Central Africa, pouring in cent of molten steel flow condition is the following kind: 1) puncture flows. Wrap infuse from steel the molten steel inside intermediate bag, did not stay inside inter bag and arrive directly irrigate affusion mouth to flow into crystallizer, this steel sheds the likelihood that did not purify inside inter bag, the field trash inter in molten steel does not have the opportunity of rise inside the bag. 2) piston flows (layer shape sheds) . Molten steel enters intermediate bag ordinal and forward advance. 3) is mixed return stream. After molten steel enters intermediate bag, mix with other part molten steel immediately, the possibility of rise of Yu of its be mingled with, with molten steel inter the course of the motion inside the bag and accident of average retention period are concerned. 4) dead band (backwater area)>Rate of flow of this area molten steel is very low, hand in with the molten steel of other area mix slow the field trash in the molten steel that enters this area is possible rise, but the existence of dead band was equivalent to narrowing the effective cubage of the bag intermediate, make molten steel inter wraps the average retention period inside to shorten, adverse to field trash rise.
Rate of flow of this area molten steel is very low, hand in with the molten steel of other area mix slow the field trash in the molten steel that enters this area is possible rise, but the existence of dead band was equivalent to narrowing the effective cubage of the bag intermediate, make molten steel inter wraps the average retention period inside to shorten, adverse to field trash rise.
Accordingly, the appearance inside the bag should avoid occurrence puncture to flow as far as possible among the design (ladle is pouring drifting position cannot leave the intermediate mouth that surround water too close) , include the average retention period inside in order to increase molten steel inter, those who be helpful for metalloid field trash eliminate. Come nearly 10 years, intermediate bag cubage has increasing tendency, experimental result explains: Field trash inter the short time of the rise inside the bag is 5min about, wrap considering molten steel inter inside medicinal powder the influence that heat drops in temperature to molten steel, intermediate bag high capacity is wrapping the average retention period inside to not be more than IOmin for molten steel.
(Among 2) the wall that block broken bits is set inside the bag (the lasher that block broken bits, board, the field trash rise that dam \ inter installs the multiform wall that block broken bits to make molten steel effectively medium inside the bag is detached, position of the height of the wall that block broken bits, setting and amount have very big effect to the purify of field trash. The wall that block broken bits can be single wall, also can be double wall, much wall, its purpose is to be used block broken bits, the cleanness that raises molten steel is spent. Its material is tall aluminium pledges commonly character, in can using bricky build by laying bricks or stones to be in, wrap together inside, also can make prefab piece put an inter inside the bag. Use low cement corundum pouring makings make the wall that block broken bits, its service life is basic as synchronous as bag line.
Include among buy, now greatly 80t. With the time that increases molten steel to stay, make field trash sufficient rise, using clean molten steel is efficient way. Include a size according to steel, as far as possible in the capacity that be the same as a bag is chosen a few bigger, the intermediate package that adopts high capacity, deep bath is the trend of current development.
For sufficient and effective use intermediate bag volume, rise of stimulative field trash, adopted is applied is inter bag adds the wall that block broken bits (lasher board) , because cupreous water inter includes actual and average retention period,compare theory average retention period is brief. Academic retention period is to show intermediate bag capacity and discharge of steel of the bag intermediate seek the cupreous water that give retention period. In actual production, flow of the molten steel inside intermediate bag is not all of , some places are fast, some places are slow, especially the backwater area with not active molten steel of existence of intermediate bag bottom, field trash rise is difficult. Inter bag adds the wall that block broken bits (lasher) , its purpose has the following to eliminate the intermediate dead band that includes bottom area. 2) improves the contrail that molten steel flows, make interface of slag of molten steel edge flows, shorten distance of field trash rise, be helpful for broken bits child absorb. The action that 3) blocks broken bits wall still can register steel bag the limitation of strong vortex flow that sheds concussion place to cause to be in local district, prevent turbulence to diffuse, cause surface wave broken bits child inside molten steel of be involved in. Accordingly, flow in molten steel element and between laminar flow cross screen to install the wall that block broken bits (lasher, board) hind, can make steel shedding directional and direct the surface that sheds bath, increase the intermediate retention period that includes molten steel thereby, raised the detached rate of field trash.
Use multiple the effect that blocks broken bits wall to have good detached metalloid field trash. Without block a wall, the effect with 2 heavy walls and ternary detached to field trash wall. Or in block a wall to go up to have up obliquitous Kong Neng makes mace current is moved more the rise that is helpful for field trash.
Block the metallurgy effect of broken bits wall:
(1) uses the wall that block broken bits clean to raising molten steel spent effect is remarkable. 3 factories include as above steel among date and 1Ot of 3 4 machine that connect casting after using the wall that block broken bits, in other technology condition changeless circumstance falls, can make field trash of intermediate bag molten steel is reduced about 30% , the field trash in casting base reduces 30%~40% .
(2) sees from comparative use result, acerbity salt be mingled with is the aluminium of board base surface that need not block broken bits wall 2.9% , after using the wall that block broken bits, decrease to 2.1% , and be mingled with of board base surface by 2.1% decrease to 0.3% .
Intermediate bag is pouring the magnesia of agglomeration of main raw material that expects magnesium blocks broken bits lasher character (MgO>90% , bulk density 3.24g/cm3) , additive of choice blame oxide and chemical bond (phosphate, hydrocarbon kind the) such as dispersive agent. Its granuality comprises 4.5~0.15mm 70% ; <0.IOmm 30% .
90% , bulk density 3.24g/cm3) , additive of choice blame oxide and chemical bond (phosphate, hydrocarbon kind the) such as dispersive agent. Its granuality comprises 4.5~0.15mm 70% ; <0.IOmm 30% .
The chemistry of the magnesian qualitative lasher that block broken bits comprises (%) : MgO 90, caO 1.5, siO2 6~7, fe2O3 2.0, al2O3 1.5.
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