U.S. patent application number 09/815292 was filed with the patent office on 2001-11-22 for liquid-cooled plate mold.
Invention is credited to Girgensohn, Albrecht, Poran, Michael, Streubel, Hans.
Application Number | 20010042608 09/815292 |
Document ID | / |
Family ID | 26005030 |
Filed Date | 2001-11-22 |
United States Patent
Application |
20010042608 |
Kind Code |
A1 |
Streubel, Hans ; et
al. |
November 22, 2001 |
Liquid-cooled plate mold
Abstract
A liquid-cooled plate mold for continuous casting of metals has
highly heat-conductive mold plates of copper or a copper alloy. The
mold plates have a water side. A fastening support for each mold
plate is provided for securing the mold plate thereon. The
fastening support is in the form of a water box or a support plate.
Fastening elements for securing the mold plates to the fastening
supports are provided. Shaped parts having a thread are arranged on
the water side of the mold plates. The shaped parts form fastening
pieces that are non-positively connected by soldering connections
or welding connections to the mold plates, wherein the fastening
elements engage the fastening pieces.
Inventors: |
Streubel, Hans; (Erkrath,
DE) ; Girgensohn, Albrecht; (Dusseldorf, DE) ;
Poran, Michael; (Westwood, NJ) |
Correspondence
Address: |
Friedrich Kueffner
Suite 1921
342 Madison Avenue
New York
NY
10173
US
|
Family ID: |
26005030 |
Appl. No.: |
09/815292 |
Filed: |
March 22, 2001 |
Current U.S.
Class: |
164/418 |
Current CPC
Class: |
B22D 11/059 20130101;
B22D 11/055 20130101 |
Class at
Publication: |
164/418 |
International
Class: |
B22D 011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 25, 2000 |
DE |
100 15 037.3 |
Aug 9, 2000 |
DE |
100 39 625.9 |
Claims
What is claimed is:
1. A liquid-cooled plate mold for continuous casting of metals, the
plate mold comprising: highly heat-conductive mold plates of copper
or a copper alloy, the mold plates having a water side; a fastening
support for each one of the mold plates configured to have the mold
plate secured thereon, wherein the fastening support is in the form
of a water box or a support plate; fastening elements configured to
secure the mold plates to the fastening supports; shaped parts
having a thread and being arranged on the water side of the mold
plates, wherein the shaped parts form fastening pieces that are
non-positively connected by soldering connections or welding
connections to the mold plates, wherein the fastening elements
engage the fastening pieces.
2. The plate mold according to claim 1, wherein the fastening
pieces are comprised of a conducting metal material selected from
the group consisting of CuAg, CuCrZr, CuNiBe, and CuNiFe.
3. The plate mold according to claim 1, wherein the soldering
connection connecting the fastening pieces to the mold plates is a
soft solder layer.
4. The plate mold according to claim 3, wherein the soft solder
layer has high shearing strength and is comprised of a solder alloy
material selected from the group consisting of L CdZn, L CdZnAg,
and L SnCdZn.
5. The plate mold according to claim 1, wherein the soldering
connection connecting the fastening pieces to the mold plates is a
hard solder layer.
6. The plate mold according to claim 5, wherein the hard solder
layer is comprised of a solder alloy material selected from the
group consisting of a copper alloy and a silver alloy.
7. The plate mold according to claim 1, wherein the soldering
connection connecting the fastening pieces to the mold plates is a
high-temperature soldering connection.
8. The plate mold according to claim 7, wherein the
high-temperature soldering connection is made by using an electron
beam or electric current.
9. The plate mold according to claim 7, wherein the
high-temperature soldering connection comprises a high-temperature
solder layer comprised of a solder material selected from the group
consisting of copper alloy and silver alloy.
10. The plate mold according to claim 1, wherein the mold plates
have solder surfaces where the fastening pieces are connected and
wherein the solder surfaces are metallized for enabling an exact
positioning of the fastening pieces.
11. The plate mold according to claim 1, wherein the fastening
pieces have an annular cross-section, wherein the mold plate has a
back side provided with shallow recesses being congruent to the
fastening pieces, wherein the fastening pieces are inserted into
the recesses and are connected by the soldering connections in the
recesses, wherein the fastening support has one or more cooling
medium bores, wherein the cooling medium bore surrounds one of the
fastening pieces with a spacing to the cooling medium bore being
provided all around the fastening piece, wherein the cooling medium
bore is in flow communication with at least one cooling medium
channel provided in the plate mold.
12. The plate mold according to claim 11, wherein the fastening
pieces have threaded inserts.
13. The plate mold according to claim 11, wherein the fastening
support has receiving bores for receiving the fastening elements in
the form of fastening bolts, wherein a diameter of the receiving
bores is greater than a diameter of a shaft of the fastening bolts
so that an annular gap is formed between the shaft of the fastening
bolt and the receiving bore, wherein each one of the annular gaps
communicates with one of the cooling medium bores.
14. The plate mold according to claim 11, wherein the cooling
medium channels are arranged in the mold plate or in the support
plate or in a plate of the water box resting against the mold
plate.
15. The plate mold according to claim 11, wherein the cooling
medium channels are located in the mold plate and are in the form
of grooves or channel bores.
16. The plate mold according to claim 15, wherein the grooves or
channel bores extend in the casting direction.
17. The plate mold according to claim 1, wherein the fastening
elements are fastening bolts with a bolt head, wherein support
elements, selected from the group consisting of washers and spring
elements, are positioned between the bolt heads and the fastening
support.
18. The plate mold according to claim 1, wherein the welding
connection connecting the fastening pieces to the mold plates is an
electron beam welding seam.
19. The plate mold according to claim 18, wherein the electron beam
welding seam is arranged on an external side of the fastening
pieces.
20. The plate mold according to claim 18, wherein the fastening
piece is annular and has an outer diameter with an enlarged
diameter portion in the area where the electron beam welding seam
is produced.
21. The plate mold according to claim 20, wherein the enlarged
diameter portion is 1 to 8 mm greater than the outer diameter.
22. The plate mold according to claim 18, wherein the mold plate
has projections in the area where the electron beam welding seam is
produced, wherein the projections have a height matching a depth of
the electron beam welding seam.
23. The plate mold according to claim 18, wherein the fastening
pieces are comprised of steel.
24. The plate mold according to claim 18, wherein the fastening
pieces are comprised of a high-strength copper alloy.
25. The plate mold according to claim 18, wherein the fastening
elements are fastening bolts.
26. The plate mold according to claim 25, wherein the fastening
bolts have an outer thread.
27. The plate mold according to claim 25, wherein the fastening
bolts have a shaft that has an enlarged diameter portion in the
area where the electron beam welding seam is produced.
28. The plate mold according to claim 27, wherein the enlarged
diameter portion is greater by 1 to 8 mm than a diameter of the
shaft outside the enlarged diameter portion.
29. The plate mold according to claim 25, wherein the fastening
bolts are comprised of steel.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a liquid-cooled plate mold for the
continuous casting of metals, in particular, of steel materials,
comprising highly heat-conductive mold plates of copper or copper
alloys which are connected by means of fastening bolts with a
fastening support in the form of a water box or a support plate,
respectively.
[0003] 2. Description of the Related Art
[0004] The plate attachment of mold plates of identical thickness
by means of welded-on bolts is known. As a result of the plate
expansion caused by temperature increase during the casting
operation, additional bending loads and tension loads result,
especially in the case of short bolts, and this can cause failure
of the welding connection.
[0005] The patent document DE 197 16 450 A1 describes a
liquid-cooled mold for continuous casting of thin steel slab with
two oppositely positioned wide sidewalls, each comprised of a
copper plate and a steel support plate. The copper plates, which
delimit a cavity of the mold, are detachably connected by means of
metal bolts of a CuNiFe alloy to the support plates. The metal
bolts are welded onto the copper plates. When doing so, a nickel
ring is additionally used as a welding additive. In the copper
plates cooling medium channels are provided, and cooling medium
bores are provided in the area of the transverse section planes of
the metal bolts. The gist of the aforementioned mold is the feature
that metal bolts of a CuNiFe alloy are being used. As a result of
using such, especially hard drawn, metal bolts, a significant
strength increase with only minimal strength fluctuations in regard
to the welding connections with a copper plate is said to be
achievable. Expediently, bolt welding methods that are known in the
art are used for the attachment of the metal bolts on the copper
plates.
[0006] The patent document WO 95/21 036 describes an assembly group
of a mold for continuous casting of steel with a support plate. A
copper or copper alloy plate with excellent heat conducting
properties is screwed onto the support plate and a relatively thin
cover layer of copper or copper alloy is soldered onto the copper
plate. If desired, the plate with excellent heat conducting
properties can be omitted and the cover layer can be soldered
directly onto the support plate. The cover layer contacts and cools
the cast strand passing through when moving through the mold. When
the cover layer shows cracks or wear, the solder connection is
melted in order to remove it and a new layer is soldered onto the
thermally conductive layer or the support plate.
[0007] The patent document DE 198 01 728 C1 discloses a continuous
casting mold for casting strands of, preferably, steel. The mold is
comprised of mold plates and water boxes which are connected to one
another and between which a water cooling system is provided with
the aid of water guiding channels. The water guiding channels are
arranged at the side of the water box facing the mold plate and not
within the mold plate. A continuous casting mold of this
configuration is improved in that the wide side of the mold with
its elements copper plate and/or water box with water guiding
channels or with a water box without water guiding channels, but
with a connecting plate having water guiding channels, is secured
by means of clamping bolts. They have substantially conical
clamping bolt heads which are secured in conical recesses of the
copper plate.
[0008] In this configuration, the bolt head of the clamping head
should have a special conical shape or be conical-lamella-shaped,
and, advantageously, should be comprised of the same material as
the copper plate of the continuous casting mold. In order to
optimize the heat conductivity between the clamping bolt/clamping
bolt head and the copper plate, the surfaces between the copper
plate and the clamping bolt/clamping bolt head can be provided with
a highly conductive layer of metal, preferably silver. A further
improvement of the connection of the copper plate and clamping bolt
is achieved when the connection is provided on the cold side of the
copper plate with a seal against water passage across the surface
in the direction of the hot side.
[0009] The patent application DE 198 35 119.9, not yet published,
concerns a mold wall of a continuous casting device for casting a
metal strand, in particular, a steel strand, with a water box and
an inner mold plate connected by bolts to the water box. The bolts
have a bolt neck, respectively, penetrating the water box and
having a bolt neck cross-section, and a bolt head, secured in the
inner mold plate and having a bolt head cross-section. For
simplifying securing of the bolt in the inner mold plate, it is
suggested that the bolt head cross-section of at least one of the
bolts is greater than the bolt neck cross-section of this bolt, and
that the inner mold plate has a groove which tapers in a direction
toward the water box for receiving the bolt head of this bolt.
[0010] Finally, the German published document 15 08 902 discloses a
liquid-cooled plate mold for continuous casting of high-melting
metals in which a mold wall is connected by fastening screws to a
support frame. Round rods are provided which are inserted into
bores of the mold wall transverse to the casting direction and are
provided with threaded bores for receiving fastening screws. The
assembly expenditure for this configuration is considerable.
SUMMARY OF THE INVENTION
[0011] It is an object of the present invention to control or
minimize for a liquid-cooled plate mold of the aforementioned kind
the difficulties and problems in the area of the connection of the
inner mold plates, comprised of copper or copper alloys, with
bearing, supporting, or shape-providing support plates or water box
plates of copper or steel during the temperature changes occurring
during the continuous casting operation and to provide a safe type
of attachment for tension-loaded as well as thermally loaded
fastening elements on inner mold plates of copper, which attachment
can be realized with economically feasible expenditure of cost and
labor and is suitable to provide a longer and failure-free service
life.
[0012] In accordance with the present invention, this is achieved
in that in the on the water side of each mold plate shaped parts
provided with threads are arranged and connected by soldering
connections or by welding connections with the mold plates in a
non-positive way as a fastening piece.
[0013] Such soldering connections and/or welding connections can be
produced easily, on the one hand, and have fatigue strength under
reversed stresses of, for example, 100 N/mm.sup.2, on the other
hand.
[0014] Advantageously, for this connection, the shaped parts or
fastening pieces are preferably produced of a material with
excellent conducting properties such as CuAg, CuCrZr, CuNiBe, or
CuNiFe.
[0015] The fastening pieces can be connected by a soft solder layer
with high shearing strength with the mold plates.
[0016] However, it is also possible to use the measure of
connecting the fastening pieces by a hard solder layer with the
mold plates, wherein preferably a silver-containing or
copper-containing hard solder is used as a solder metal.
[0017] It is furthermore possible to connect the fastening piece
with the mold plate by high-temperature soldering. The heating of
the soldering location can be realized in this context by electron
beam or by electric current.
[0018] It is particularly advantageous to connect the fastening
piece with the mold plate by electron beam welding.
[0019] For this purpose, the fastening piece can also be inserted
into a shallow, round recess of relatively minimal depth at the
backside of the mold plate. The welding connection is then carried
out annularly along the separating location between the mold plate
and the fastening piece. The electron beam can impinge
perpendicularly or at an angle onto the surface of the mold. The
fastening pieces can be provided with a step or shoulder which is
of such a size that it is flush with the upper rim of the recess,
as illustrated in FIG. 2.
[0020] The fastening pieces, as described above, can be produced of
a metal material of good conducting properties or a suitable steel
alloy.
BRIEF DESCRIPTION OF THE DRAWING
[0021] In the drawing:
[0022] FIG. 1 is a section of a portion of an inner mold plate with
a shaped part attached by soldering and fastening bolts of a
support plate screwed into the shaped part;
[0023] FIG. 2 shows in section a detail of FIG. 1 with the shaped
part attached by electron beam welding.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The part of a liquid-cooled plate mold illustrated in FIG. 1
for continuous casting of high-melting metals, such as steel,
comprises a highly heat-conductive mold plate 1 of copper or copper
alloy which is connected by means of fastening elements in the form
of fastening bolts 2 on a fastening support. The fastening support
can be a water box, e.g., the backside of the water box, or a
support plate 4 provided with channels 3 for the cooling water. The
channels for the cooling water can also be located within the mold
plate.
[0025] According to the invention, on the water side of the mold
plate 1 shaped parts 6 with threaded bores 5 for screwing in the
fastening bolts 2 are arranged and connected by a non-positive
connection with the mold plate 1 by means of soldering connections
7, 7' in order to provide fastening pieces. The shaped parts or
fastening pieces 6 are preferably produced of a metal material
having good conducting properties such as CuAg, CuCrZr, CuNiBe, or
CuNiFe. The fastening pieces 6 are connected by a soft solder layer
7 with the mold plates 1. The soft solder layer 7 with a high
shearing strength is preferably produced of a solder material of
the alloys L CdZn or L CdZnAg or L SnCdZn.
[0026] However, it is also possible to employ the measure of
connecting the fastening pieces 6 by a hard soldering layer 7' with
the mold plates 1, wherein the solder metal is preferably copper
solder alloy or a silver solder alloy.
[0027] It is moreover possible to connect the fastening pieces 6 by
high-temperature soldering by means of an electron beam or by means
of electrical current with the mold plates 1.
[0028] The hard solder connection provides at soldering
temperatures above approximately 450.degree. C. a comparatively
high strength in comparison to a soft solder connection; however,
in comparison to the soft solder connection, it is somewhat more
prone to solder fractures when subjected to changing temperatures
and requires a higher expenditure during manufacture and cannot be
removed (by melting) without affecting the surrounding material, in
particular, copper, in the case of repairs.
[0029] One embodiment of the invention suggests that the soldering
surface of the mold plates for the fastening pieces 6 is metallized
for an exact positioning of the fastening pieces 6.
[0030] An inventive embodiment also suggests that the fastening
pieces 6 are shaped parts with preferably annular cross-section
which are inserted into congruent shallow recesses 8 of relatively
minimal depth (see FIG. 1), for example, up to 5 mm, in the
backside of the mold plate 1 and are soldered therein, and that the
support plate 4 has a cooling medium bore 9 having a spacing on all
sides relative to the fastening piece 6 positioned in the bore 9
and being in flow communication with at least one cooling medium
channel 3. The cooling medium bore 9 can also be provided in the
plate of the water box.
[0031] This configuration of the bolt attachment has the advantage
that the fastening piece 6 as well as the shaft of the bolt 2 are
exposed to the flow of cooling water and are therefore sufficiently
cooled. Thus, the endangerment of the solder connections is
reliably prevented.
[0032] For the same purpose, according to another embodiment of the
invention, it is suggested to provide the support plate 4 with
receiving bores 2' for receiving the fastening bolts 2, which
receiving bores 2' have a diameter that is greater than the shaft
diameter of the fastening bolts 2. This results in the formation of
annular gaps 10, and, according to the invention, each of these
annular gaps 10 is connected with a cooling medium bore 9 supplying
cooling water.
[0033] The aforementioned embodiment has furthermore the advantage
that temperature-caused expansion differences between the mold
plate 1 and the support plate 4 can be compensated easily.
[0034] Moreover, if desired, it is possible to use the measure of
arranging the cooling medium channels 3 either in the mold plate 1
or in the support plate 4 or in a plate of the water box contacting
the mold plate.
[0035] Finally, the cooling medium channels 3 in the mold plate 1
can be configured either as grooves or as channel bores extending
preferably in the casting direction.
[0036] FIG. 2 shows in section a detail of FIG. 1 with the shaped
part 6, which, as an alternative solution of the aforementioned
object, is fixedly connected by an electron beam welding seam 12
with the mold plate 1. The welding seam is positioned at the
exterior side of the shaped part (fastening piece) 6. Before
welding is carried out, the outer diameter of the shaped part,
which in cross-section is annular, has a diameter which is greater
by 1 to 8 mm in the area of the welding seam 12. For the electron
beam welding step, the mold plate 1 can have in the area of the
attachment a minimal material projection which corresponds
approximately to the height of the welding seam depth. The shaped
part (fastening piece) 6 is provided with an inner thread 5 for
attachment of the fastening bolt 2 (FIG. 1). The shaped part can
also be in the form of a bolt with outer thread.
[0037] The channels 3 of the support plate 4 for supplying cooling
water are indicated only partially, and the bore 9 supplying the
cooling water is also only partially indicated.
[0038] While specific embodiments of the invention have been shown
and described in detail to illustrate the inventive principles, it
will be understood that the invention may be embodied otherwise
without departing from such principles.
* * * * *