Build-up mold for continuous casting

Details Build-up mold for continuous casting Build-up mold for continuous casting

2002-03-05

2004-06-01

Stoner, Kiley (Department: 1725)

Metal founding

Means to shape metallic material

Continuous or semicontinuous casting

C164S443000

Reexamination Certificate

active

06742571

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a build-up mold for continuous casting which produces moldings by feeding molten metal such as molten steel, etc., into the upper open portion of a mold, cooling the same from the periphery of the mold via the mold wall, and continuously pulling out solidified molding pieces through the lower portion of the mold.
BACKGROUND OF THE INVENTION
In prior arts, a build-up mold for continuous casting is constructed by making a pair of short-sided molds orthogonal to and between a pair of long-sided molds disposed in parallel to each other and assembling the entirety like boxes.
Respective molds are made of a cooling plate, which is made of copper or the like, and a cooling plate supporting panel (back-up plate) that supports the cooling plate at its backside. The cooling plate supporting panel is connected to the cooling plate, slit grooves are formed on the back side of the casting side of the cooling plate, onto which molten metal is fed, an appointed amount of cooling water is caused to flow into the slit grooves in a state of use, the molten metal that is fed through an opening at the upper portion of the box-shaped mold is cooled down via the cooling plate, and the molten metal is solidified.
Screw holes are provided on the rear side of the copper plate, which becomes a cooling plate, in order to tighten the back-up plate thereon. Therefore, since the cooling grooves are provided apart from the screw holes, the pitch at which the cooling grooves are provided tends to become wider than the original pitch, at which installation is intended, wherein uneven states of cooling resulting therefrom have been solved by some technologies disclosed previously.
However, where molten metal is molded while agitating the same with an electromagnetic force in a mold in order to cast high quality molding pieces, it is requested that the thickness of the copper plate is made thin like 10 mm through 30 mm in order to efficiently transmit the electromagnetic force to the agitation of the molten metal.
Since a depth necessary for the screw holes to tighten the copper plate cannot be secured in such a thin copper plate, a protruding boss portion is provided at the screw portions on the rear side of the copper plate. In the case of the copper plate having boss portions provided thereon, cooling grooves to be installed are located outside the boss portions, and the installation pitch of straight cooling grooves is made excessively wide, wherein the entirety of rows is made into an uneven cooling state, and this may cause the molding pieces to be subjected to cracks due to uneven solidification.
Also, in order to efficiently transmit the electromagnetic force in the copper plate used for electromagnetic agitation, the material of the copper plates may be an alloy having a low electric conductivity. Since the material is low in electric conductivity, the thermal conductivity is also made low, wherein a further uneven cooling structure will occur. Therefore, a structure for making the cooling even is required.
With respect to such build-up molds for continuous casting, for example, the following technologies are disclosed.
(1) Japanese Unexamined Patent Publication No. 1996-52537 (hereinafter called “aa” publication) describes a mold wall for continuous casting, in which the pitches at the opening side of respective slit grooves are made wider at portions that enclose the screwing holes of attaching bolts and holes for attaching a thermocouple, and are made narrower at portions that do not enclose the same, wherein two slit grooves that constitute a wider opening pitch are constructed to be inclined so that they are drawn near each other inwardly from the opening portion toward the groove bottom portion, wherein the pitches between the groove bottom portions of the respective slit grooves are made equal to each other.
(2) Japanese Unexamined Patent Publication No. 1990-59144 (hereinafter called “b” publication) proposes such a type that slit grooves within 100 mm from the vicinity of the molten steel meniscus of the mold wall are disposed so as to bypass at the surrounding of screwing holes of the attaching bolts, wherein the cooling efficiency around the screwing holes is improved.
FIG. 5
is a view explaining the disposed state of slit grooves at the surrounding of the tightening members in such prior art build-up molds for continuous casting.
In
FIG. 5
,
50
denotes a prior art build-up mold for continuous casting,
51
denotes a cooling plate on which slit grooves
52
through
56
which permit cooling water to flow are formed,
57
denotes a cooling plate supporting panel that seals the opening side of the slit grooves
52
through
56
and builds up two sets of cooling plates each having a longer side and a shorter side to be box-shaped,
58
denotes a screwing hole of a bolt or the like that connects and tightens the cooling plate
51
and the cooling plate supporting panel
57
together.
Also, such a cooling structure has also been proposed as a prior art, in which cooling grooves are disposed so as to turn around the boss portions in order to evenly cool down the surroundings of the boss portions provided so as to protrude from the cooling plate.
However, prior art build-up molds for continuous casting have the following problems.
(1) In the build-up mold for continuous casting, which has inwardly inclined slit grooves described in the “aa” publication, it is necessary to repeatedly carry out positioning operations for the respective surroundings of a plurality of screwing holes and attaching holes in order to set a copper plate at an appointed angle by inclining the same when milling or cutting the copper plate, which becomes a cooling plate, by using a milling machine, etc., and a number of steps of machining are required, wherein several problems arise, that is, productivity and manpower saving efficiency are worsened, it is difficult to secure milling or cutting accuracy, a slope in temperature is recognized between the surroundings of the attaching holes and the other portions, and unevenness occurs in the cooling.
(2) Also, in the method for controlling the cooling efficiency at respective positions of the mold wall by adjusting the pitches between slit grooves formed on the cooling plate, it is difficult to uniformly adjust the thermal characteristics such as thermal conductivity over the entire surface of the cooling plate even if the pitches of the slit grooves are merely varied. Therefore, various problems occur. For example, quality of molding pieces may deteriorate due to unevenness in the cooling, and a break-out may occur, by which the solidification shells are broken during continuous casting, and surface coating may be damaged due to a local increase in the temperature of the cooling plate.
(3) In the art disclosed in the “b” publication, which is shown in
FIG. 5
, the pressure loss of cooling water in slalom type slit grooves
52
and
56
having large bending at the surroundings of the screwing holes
58
is made especially large, and the velocity of the cooling water flowing into these slit grooves
52
and
56
becomes slower than the velocity of cooling water in the slit groove
55
which has a small curvature ratio, is shaped to be nearly straight, and is installed at the middle, wherein a problem arises in that the cooling capacity is lowered, and the cooling is made uneven.
(4) In the method for cooling, in which cooling grooves are provided so as to turn around the boss portions, the mold has such a structure wherein cooling grooves are repeatedly bifurcated and connected together before and after the boss portions. Due to influences brought about by eddies and pressure loss, which are produced by bifurcation and connection, the velocity distribution of the cooling water becomes remarkably complicated, wherein various problems arise in that impurities in the cooling water are likely to be adhered to the bifurcated portions to cause the cooling effect to be spoiled, and simultaneously, analysis of the cooling eff

Affiliated with

Also associated with

Rating

Build-up mold for continuous casting does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Build-up mold for continuous casting, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Build-up mold for continuous casting will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3332733