A kind of aluminium alloy round cast ingot oil-air lubrication film casting method
Technical field
The present invention relates to a kind of aluminium alloy round cast ingot oil-air lubrication film casting methods.
Background technique
The ingot surface quality that traditional water cooling casting obtains is poor, there is the defects of segregation, loose, subsequent that railway carriage is needed to add
Work increases casting cost.The ingot casting of oil-air lubrication casting has surface smooth, and small, dense internal organization of degree of segregation etc. is excellent
After the completion of the preparation of point, usually aluminium alloy melt, enter shunting disk through chute, enters back into each crystallizer and carry out oil-air lubrication film
Casting, this method pass through the dry gas for making have certain pressure and lubricating oil through crystallizer porous graphite ring, make graphite annulus
One layer of uniform and stable oil gas film is formed between inner wall and aluminium alloy melt scull.The presence of oil gas film: one, it is thin to change ingot casting
The contact condition of scull and crystallizer inner wall reduces the frictional force of scull and crystallizer inner wall, and then reduces ingot casting surface hair
Raw the defects of drawing trace, drawing crack leakage aluminium;Two, change the solidification and heat transfer mode of ingot casting, reduce laterally heat transfer, is i.e. reduction ingot casting is crystallizing
An intensity of cooling on device graphite annulus, keeps liquid cave straight, and aluminium alloy crystal grain is fine and close.
But oil-air lubrication crystallizer belongs to precision casting mold, and crystallizer needs to control logical oil ventilation, initial operation process
Complexity needs operator's operation with higher horizontal, and meeting in actual production faces following problem: first is that: when melt exists
In crystallizer the filling time it is too short will lead to due to the too thin easy bleedout of scull in ingot casting downdraw process, the filling time is too long, easily leads
The suspension flexures or melt for causing ingot casting solidify in reducing sleeve, due to the solid-state portion of reducing sleeve solidification in downdraw process
Divide drop-down is unstable to cause to leak aluminium, the filling time includes the retention time of casting machine setting and begins to flow into knot from aluminium alloy melt
Brilliant device to aluminium alloy melt liquid level reaches this period between 60~80mm, is denoted as the time of driving, if the time of driving is
A constant, then the control of retention time is an important factor for influencing aluminium alloy cast ingot;Second is that: exist in casting process and emits rolling
Bubbling length is big in air pocket and casting process, so that ingot casting is generated oxide slag inclusion etc., influences ingot quality and yield rate.
When casting enters the stabilization sub stage, when usually casting length reaches 80-120mm, if ingot casting table can be found in time
The defects of face is with the presence or absence of trace is drawn, takes timely measure, it will be able to solve the defect, make the subsequent aluminium alloy cast ingot table cast out
Face is high-quality.
Problem above is aluminium alloy casting field technical staff's letter critical problem to be solved, is invented herein a set of suitable
For Φ 120 to the production operation method of 330 scale aluminium alloy of Φ circle ingot casting.
Summary of the invention
The present invention in view of the deficiency of the prior art, provides a kind of aluminium alloy round cast ingot oil-air lubrication film casting side
Method.
The technical scheme to solve the above technical problems is that a kind of aluminium alloy round cast ingot oil-air lubrication film casting side
Method, comprising the following steps:
Step 1, cleaning crystallizer, the crystallizer include hot tap, crystallizer ontology, cooling water cavity, venthole, logical oil
Hole, pinboard and graphite annulus, the hot tap are arranged above the crystallizer ontology;
The whether logical oil ventilation of step 2, each crystallizer of test
The each crystallizer air valve cast on flow table is opened to the maximum, total oil pressure is adjusted to 3~4MPa, total gas pressure is adjusted to
0.5MPa, the total gas pressure are the sum of air pressure in each crystallizer venthole, and total oil pressure is in each crystallizer oil-through-hole
The sum of oil pressure, and multiple pulse note hydrocarbon tests are carried out, and obstructed oil or airproof crystallizer are replaced, and is tested,
Until all crystallizers are all qualified;
Step 3 prepares aluminium alloy melt, and primary aluminum and other alloys are proportionally added in smelting furnace and carry out melting, melts
The process needs of refining are stirred, and are formed aluminium alloy melt, are kept the temperature of aluminium alloy melt at 740~760 DEG C;
Step 4, the setting of casting retention time
When casting machine is driven, the retention time is set, the retention time starts to dummy ingot pedestal for casting machine and starts to act
Between time, be denoted as t1, empirical equation should be met:
t1=0.033*D+4.28
Wherein, t1For the retention time of casting machine setting, unit s;D be different size ingot diameters value, 120mm≤D≤
330mm;
Step 5, casting
A) the gentle pressure of crystallizer oil pressure is adjusted before casting, by total adjustment of oil pressure of crystallizer in 3~4MPa, total gas pressure is adjusted
To P1, wherein P1=0.3~0.5MPa, air pressure of the number of crystallizer between 20~50, in the venthole of each crystallizer
Between 0.006~0.025MPa, the oil pressure in oil-through-hole is between 0.06~0.2MPa, compressed air in venthole and logical
Lubricating oil in oilhole mixes and forms a thin layer oil-gas pad film along crystallizer inner ring;
B) when casting starts, aluminium alloy melt flows to casting flow table through the chute of certain length from smelting furnace, flows slowly into
The hot tap of crystallizer guarantees aluminium alloy melt between 690~735 DEG C of casting temperature of flow table, in the hot tap when crystallizer
When aluminium alloy melt liquid level reaches 60~80mm, starting casting program, casting machine starting, at this point, dummy ingot pedestal does not work,
Wherein, the hot tap that crystallizer is begun to flow into from aluminium alloy melt reaches this between 60~80mm to aluminium alloy melt liquid level
The section time is denoted as t2;
C) pass through time t1Afterwards, dummy ingot pedestal is begun to decline with the speed of 1~10mm/min;
D) casting length reaches L1When, wherein L1When=20~60mm, casting speed reaches between 38~85mm/min, right
Crystallizer total gas pressure carries out boosting adjusting, and total gas pressure boosts to P2, wherein P2=0.6~1MPa;In the venthole of each crystallizer
Air pressure between 0.012~0.05MPa, and adjust the air valve of each crystallizer, air valve is opened bigger, and bubbling is more serious, and
Air valve is opened smaller, then bubbling is smaller or not bubbling, and around this principle, adjusting each crystallizer makes its slight bubbling as early as possible,
Specifically: the excessive crystallizer of bubbling is slowly adjusted to rigid not bubbling, the timely of not bubbling on flow table barostat
Slowly make its rigid bubbling;
E) casting length reaches L2When, wherein L2When=80~120mm, reduction regulation, total gas are carried out to crystallizer total gas pressure
Pressure drop is to P3, wherein P3Between=0.4~0.65MPa, 0.008~0.033MPa of air pressure in the venthole of each crystallizer, then
Until when being only transferred to not bubbling to each crystallizer of bubbling;Casting enters the stabilization sub stage, and casting speed is in 50~125mm/min.
The beneficial effects of the present invention are:
1) control of reasonable retention time can prevent because of the too thin easy bleedout of scull caused by the filling time is too short
Problem, and ingot casting suspension flexures can be prevented, or the problem of leakage aluminium;
2) control by stages air pressure is originated in casting, the oil gas film of stable and uniform can be formed;Bubbling is controlled in casting process,
Each crystallizer is adjusted in time, and ingot casting will not generate oxide slag inclusion, and ingot quality is good, high yield rate.
Further, crystallizer is cleared up in step 1 specifically includes following two aspect:
On the one hand, first graphite annulus liner and pinboard are polished completely with steel wool, then with rust remover along graphite annulus four
All uniformly sprinklings, then by graphite annulus wiped clean;
On the other hand, it is brushed with pinboard of the boron nitride coating to crystallizer, again by crystallizer graphite annulus and switching
Plate junction is brushed, whole to brush 2~3 times.
Beneficial effect using above-mentioned further technical solution is:
1) by graphite annulus wiped clean, it can be ensured that oil is ventilative thoroughly for graphite annulus, forms stable oil gas film;
2) the junction brushing boron nitride of pinboard and crystallizer and pinboard, can prevent compressed gas between the two
Gap in escape, cause ingot casting thin scull destroy or at pinboard occur hang aluminium make ingot casting occur drawing crack, leakage al defect.
Further, the e in step 5) in, when find ingot casting surface occur draw trace when, can slow, multiple adjusting air valve, add
Atmospheric flow, but should be ensured that each crystallizer not bubbling.
Beneficial effect using above-mentioned further technical solution is: when the defects of drawing trace occurs in ingot casting surface, illustrating to rub
Power is big, and oil-air lubrication membrane permeability is poor, and slow, multiple increase gas flow adjusts the gas permeability of lubricating film, guarantees subsequent aluminium
Alloy cast ingot surface quality is good, is not in the defects of drawing trace.
Further, the ingot casting for being 120mm for diameter, the casting speed of stabilization sub stage 115~125mm/min it
Between.
Further, the ingot casting for being 330mm for diameter, the casting speed of stabilization sub stage is between 50~60mm/min.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of crystallizer in the present invention;
Fig. 2 is the variation schematic diagram of cast sections casting length of the present invention and total gas pressure;
In the accompanying drawings, list of designations represented by each label is as follows: 1, hot tap;2, pinboard;3, graphite annulus;4, lead to
Oilhole;5, venthole;6, cooling water cavity;7, crystallizer ontology.
Specific embodiment
The principle and features of the present invention will be described below with reference to the accompanying drawings, and the given examples are served only to explain the present invention, and
It is non-to be used to limit the scope of the invention.
Embodiment 1
The aluminium alloy round cast ingot of casting 120 specification of Φ, a kind of aluminium alloy round cast ingot oil-air lubrication film casting method, including with
Lower step:
Step 1, cleaning crystallizer, as shown in Figure 1, the crystallizer include hot tap 1, crystallizer ontology 7, cooling water cavity 6,
7 top of the crystallizer ontology is arranged in venthole 5, oil-through-hole 4, pinboard 2 and graphite annulus 3, the hot tap 1, specifically include with
Lower two aspects:
On the one hand, first 3 liner of graphite annulus and pinboard 2 are polished completely with steel wool, then with rust remover along graphite annulus 3
Surrounding is uniformly sprayed, then by 3 wiped clean of graphite annulus;
On the other hand, it is brushed with pinboard of the boron nitride coating to crystallizer, again by crystallizer graphite annulus and switching
Plate junction is brushed, whole to brush 2~3 times.
The whether logical oil ventilation of step 2, each crystallizer of test
The each crystallizer air valve cast on flow table is opened to the maximum, total oil pressure is adjusted to 3~4MPa, total gas pressure is adjusted to
0.5MPa, and multiple pulse note hydrocarbon tests are carried out, and obstructed oil or airproof crystallizer are replaced, and is tested, directly
Until all crystallizers are all qualified;
Step 3 prepares aluminium alloy melt, and primary aluminum and other alloys are proportionally added in smelting furnace and carry out melting, melts
The process needs of refining are stirred, and are formed aluminium alloy melt, are kept the temperature of aluminium alloy melt at 740~760 DEG C;
Step 4, the setting of casting retention time
When casting machine is driven, the retention time is set, the retention time starts to dummy ingot pedestal for casting machine and starts to act
Between time, be denoted as t1, empirical equation should be met:
t1=0.033*D+4.28
Wherein, t1For the retention time of casting machine setting, unit s;D=120mm;Retention time t is calculated1=
8.24s about takes 8s.
Step 5, casting
A) the gentle pressure of crystallizer oil pressure is adjusted before casting, by total adjustment of oil pressure of crystallizer in 3MPa, total gas pressure is adjusted
0.3MPa, the number of crystallizer is between 50, air pressure in the venthole of each crystallizer 0.006MPa, oil-through-hole between
Lubricating oil of the interior oil pressure in the compressed air and oil-through-hole in 0.06MPa, venthole mixes and along crystallizer annular
At a thin layer oil-gas pad film;
B) when casting starts, aluminium alloy melt flows to casting flow table through the chute of certain length from smelting furnace, flows slowly into
The hot tap of crystallizer guarantees aluminium alloy melt between 690~735 DEG C of casting temperature of flow table, when aluminium in the hot tap of crystallizer
When alloy melt liquid level reaches 60~80mm, starting casting program, casting machine starting, at this point, dummy ingot pedestal does not work,
In, hot tap to the aluminium alloy melt liquid level for beginning to flow into crystallizer from aluminium alloy melt reaches this section between 60~80mm
Time is t2, t2For constant;
C) pass through time t1Afterwards, dummy ingot pedestal is begun to decline with the speed of 1~10mm/min;
D) when casting length reaches 20mm, casting speed reaches between 85mm/min, boosts to crystallizer total gas pressure
It adjusts, total gas pressure boosts to 0.6MPa, and the air pressure in the venthole of each crystallizer adjusts each knot between 0.012MPa
The air valve of brilliant device, air valve are opened bigger, and bubbling is more serious, and that air valve is opened is smaller, then bubbling is smaller or not bubbling, according to this
A principle, adjusting each crystallizer makes its slight bubbling as early as possible, specifically: by crystallization that bubbling is excessive on flow table barostat
Device is slowly adjusted to rigid not bubbling, not bubbling is slowly made its rigid bubbling in time;
E) when casting length reaches 80mm, reduction regulation is carried out to crystallizer total gas pressure, total gas pressure is down to 0.4MPa, only
Until when being transferred to not bubbling to bubbling crystallizer;When find ingot casting surface occur draw trace when, can slow, multiple adjusting air valve, add
Atmospheric flow, but should be ensured that each crystallizer not bubbling;Casting enters the stabilization sub stage, casting speed 115~
125mm/min。
Embodiment 2
Cast the aluminium alloy round cast ingot of 200 specification of Φ, comprising the following steps: step 1, cleaning crystallizer, the crystallizer
Including hot tap 1, crystallizer ontology 7, cooling water cavity 6, venthole 5, oil-through-hole 4, pinboard 2 and graphite annulus 3, the hot tap 1 is set
7 top of crystallizer ontology is set, in terms of specifically including following two:
On the one hand, first 3 liner of graphite annulus and pinboard 2 are polished completely with steel wool, then with rust remover along graphite annulus 3
Surrounding is uniformly sprayed, then by 3 wiped clean of graphite annulus;
On the other hand, brushed with pinboard 2 of the boron nitride coating to crystallizer, again by crystallizer graphite annulus 3 with turn
Fishplate bar junction 2 is brushed, whole to brush 2~3 times.
The whether logical oil ventilation of step 2, each crystallizer of test
The each crystallizer air valve cast on flow table is opened to the maximum, total oil pressure is adjusted to 3.5MPa, total gas pressure is adjusted to
0.5MPa, and multiple pulse note hydrocarbon tests are carried out, and obstructed oil or airproof crystallizer are replaced, and is tested, directly
Until all crystallizers are all qualified;
Step 3 prepares aluminium alloy melt, and primary aluminum and other alloys are proportionally added in smelting furnace and carry out melting, melts
The process needs of refining are stirred, and are formed aluminium alloy melt, are kept the temperature of aluminium alloy melt at 740~760 DEG C;
Step 4, the setting of casting retention time
When casting machine is driven, the retention time is set, the retention time starts to dummy ingot pedestal for casting machine and starts to act
Between time, be denoted as t1, empirical equation should be met:
t1=0.033*D+4.28
Wherein, t1For the retention time of casting machine setting, unit s;T is calculated by formula in D=200mm1=
10.88s taking t1=11s;
Step 5, casting
A) the gentle pressure of crystallizer oil pressure is adjusted before casting, by total adjustment of oil pressure of crystallizer in 3.5MPa, total gas pressure is adjusted
In 0.4MPa, for the number of crystallizer between 20, air pressure in the venthole 5 of each crystallizer 0.02MPa between leads to oil
Lubricating oil of the oil pressure in the compressed air and oil-through-hole 4 in 0.175MPa, venthole 5 in hole 4 mixes and along crystallizer
Inner ring forms a thin layer oil-gas pad film;
B) when casting starts, aluminium alloy melt flows to casting flow table through the chute of certain length from smelting furnace, flows slowly into
The hot tap of crystallizer guarantees aluminium alloy melt between 690~735 DEG C of casting temperature of flow table, when aluminium in the hot tap of crystallizer
When alloy melt liquid level reaches 60~80mm, starting casting program, casting machine starting, at this point, dummy ingot pedestal does not work,
In, hot tap to the aluminium alloy melt liquid level for beginning to flow into crystallizer from aluminium alloy melt reaches this section between 60~80mm
Time is t2, t2For constant;
C) pass through time t1Afterwards, dummy ingot pedestal is begun to decline with the speed of 1~10mm/min;
D) when casting length reaches 50mm, casting speed reaches between 67mm/min, boosts to crystallizer total gas pressure
It adjusts, total gas pressure boosts to 0.8MPa, and the air pressure in the venthole of each crystallizer adjusts each knot between 0.04MPa
The air valve of brilliant device, air valve are opened bigger, and bubbling is more serious, and that air valve is opened is smaller, then bubbling is smaller or not bubbling, according to this
A principle, adjusting each crystallizer makes its slight bubbling as early as possible, specifically: by crystallization that bubbling is excessive on flow table barostat
Device is slowly adjusted to rigid not bubbling, not bubbling is slowly made its rigid bubbling in time;
E) when casting length reaches 100mm, reduction regulation is carried out to crystallizer total gas pressure, total gas pressure is down to 0.5MPa,
Until when being only transferred to not bubbling to bubbling crystallizer;When find ingot casting surface occur draw trace when, can slow, multiple adjusting air valve,
Gas flow is increased, but should be ensured that each crystallizer not bubbling;Casting enters the stabilization sub stage, casting speed 90~
100mm/min。
Embodiment 3
Cast the aluminium alloy round cast ingot of 330 specification of Φ, comprising the following steps: step 1, cleaning crystallizer, the crystallizer
Including hot tap 1, crystallizer ontology 7, cooling water cavity 6, venthole 5, oil-through-hole 4, pinboard 2 and graphite annulus 3, the hot tap 1 is set
7 top of crystallizer ontology is set, in terms of specifically including following two:
On the one hand, first 3 liner of graphite annulus and pinboard 2 are polished completely with steel wool, then with rust remover along graphite annulus 3
Surrounding is uniformly sprayed, then by 3 wiped clean of graphite annulus;
On the other hand, brushed with pinboard 2 of the boron nitride coating to crystallizer, again by crystallizer graphite annulus 3 with turn
2 junction of fishplate bar is brushed, whole to brush 2~3 times.
The whether logical oil ventilation of step 2, each crystallizer of test
The each crystallizer air valve cast on flow table is opened to the maximum, total oil pressure is adjusted to 4MPa, total gas pressure is adjusted to
0.5MPa, and multiple pulse note hydrocarbon tests are carried out, and obstructed oil or airproof crystallizer are replaced, and is tested, directly
Until all crystallizers are all qualified;
Step 3 prepares aluminium alloy melt, and primary aluminum and other alloys are proportionally added in smelting furnace and carry out melting, melts
The process needs of refining are stirred, and are formed aluminium alloy melt, are kept the temperature of aluminium alloy melt at 740~760 DEG C;
Step 4, the setting of casting retention time
When casting machine is driven, the retention time is set, the retention time starts to dummy ingot pedestal for casting machine and starts to act
Between time, be denoted as t1, empirical equation should be met:
t1=0.033*D+4.28
Wherein, t1For the retention time of casting machine setting, unit s;T is calculated according to formula in D=330mm1=
15.17s taking t1=15s;
Step 5, casting
A) the gentle pressure of crystallizer oil pressure is adjusted before casting, by total adjustment of oil pressure of each crystallizer in 4MPa, total gas pressure is adjusted
In 0.5MPa, between 20, air pressure in the venthole 5 of each crystallizer 0.025MPa between leads to the number of crystallizer
Lubricating oil of the oil pressure in the compressed air and oil-through-hole 4 in 0.2MPa, venthole 5 in oilhole 4 mixes and along crystallizer
Inner ring forms a thin layer oil-gas pad film;
B) when casting starts, aluminium alloy melt flows to casting flow table through the chute of certain length from smelting furnace, flows slowly into
The hot tap of crystallizer guarantees aluminium alloy melt between 690~735 DEG C of casting temperature of flow table, when aluminium in the hot tap of crystallizer
When alloy melt liquid level reaches 60~80mm, starting casting program, casting machine starting, at this point, dummy ingot pedestal does not work,
In, hot tap to the aluminium alloy melt liquid level for beginning to flow into crystallizer from aluminium alloy melt reaches this section between 60~80mm
Time is t2, t2For constant;
C) pass through time t1Afterwards, dummy ingot pedestal is begun to decline with the speed of 1~10mm/min;
D) when casting length reaches 60mm, casting speed reaches between 38mm/min, boosts to crystallizer total gas pressure
It adjusts, total gas pressure boosts to 1MPa, and the air pressure in the venthole 5 of each crystallizer adjusts each crystallization between 0.05MPa
Device makes its slight bubbling as early as possible, specifically: the excessive crystallizer of bubbling has slowly been adjusted to just not on flow table barostat
Not bubbling is slowly made its rigid bubbling by bubbling in time;
E) when casting length reaches 120mm, reduction regulation is carried out to crystallizer total gas pressure, total gas pressure is down to 0.65MPa,
Until when being only transferred to not bubbling to bubbling crystallizer;When find ingot casting surface occur draw trace when, can slow, multiple adjusting air valve,
Gas flow is increased, but should be ensured that each crystallizer not bubbling;Casting enters the stabilization sub stage, casting speed 50~
60mm/min。
The foregoing is merely presently preferred embodiments of the present invention, is not intended to limit the invention, it is all in spirit of the invention and
Within principle, any modification, equivalent replacement, improvement and so on be should all be included in the protection scope of the present invention.