U.S. patent application number 15/569301 was filed with the patent office on 2018-05-03 for method and device for generating deformation twinning in a metal.
The applicant listed for this patent is SANDVIK INTELLECTUAL PROPERTY AB. Invention is credited to Mikael GREHK, Sofie HOGBERG, Anders THYLEN, Lars WICKSTROM.
Application Number | 20180119246 15/569301 |
Document ID | / |
Family ID | 53015603 |
Filed Date | 2018-05-03 |
United States Patent
Application |
20180119246 |
Kind Code |
A1 |
THYLEN; Anders ; et
al. |
May 3, 2018 |
METHOD AND DEVICE FOR GENERATING DEFORMATION TWINNING IN A
METAL
Abstract
A method of generating twin lamellas in a metal body includes
the steps of introducing the metal body into a chamber, filling the
chamber with a cooling medium having a temperature that will enable
generation of twin lamellas in the metal body upon deformation
thereof, and deforming the metal body while the latter is
surrounded by the cooling medium. The cooling medium surrounds the
metal body upon deformation of the latter is in a gaseous state.
The present disclosure also relates to a device for generating twin
lamellas in the metal body, the device including a chamber, a
chamber inlet connected to a cooling medium source, and a
deformation device arranged to deform the metal body. The
deformation device is positioned inside the chamber so that the
metal body will be surrounded by the cooling medium in a gaseous
state while being deformed by the deformation device.
Inventors: |
THYLEN; Anders; (Jarbo,
SE) ; WICKSTROM; Lars; (Sandviken, SE) ;
HOGBERG; Sofie; (Gavle, SE) ; GREHK; Mikael;
(Borlange, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SANDVIK INTELLECTUAL PROPERTY AB |
Sandviken |
|
SE |
|
|
Family ID: |
53015603 |
Appl. No.: |
15/569301 |
Filed: |
April 25, 2016 |
PCT Filed: |
April 25, 2016 |
PCT NO: |
PCT/EP2016/059112 |
371 Date: |
October 25, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C21D 9/08 20130101; C22F
1/002 20130101; C21D 1/667 20130101; C21D 8/00 20130101; C22F 1/02
20130101; C21D 1/62 20130101; C21D 2201/00 20130101; C21D 8/06
20130101; C21D 8/10 20130101; C21D 9/525 20130101 |
International
Class: |
C21D 9/52 20060101
C21D009/52; C21D 9/08 20060101 C21D009/08; C21D 8/10 20060101
C21D008/10; C21D 8/06 20060101 C21D008/06; C21D 1/667 20060101
C21D001/667; C22F 1/00 20060101 C22F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 27, 2015 |
EP |
15165228.6 |
Claims
1. A method of generating twin lamellas in a metal body, comprising
the steps of: introducing said metal body into a chamber; filling
said chamber with a cooling medium having a temperature arranged to
enable generation of twin lamellas in the metal body upon
deformation thereof; and deforming said metal body while the metal
body is surrounded by said cooling medium, wherein the cooling
medium surrounding said metal body upon deformation of the metal
body is in a gaseous state.
2. The method according to claim 1, wherein the temperature inside
the chamber is controlled by controlled introduction of said
cooling medium into the chamber in at least two different locations
within the chamber, wherein the cooling medium in a first location
is directed directly onto the metal body being deformed, and in a
second location is directed onto a deformation device used to
deform said metal body.
3. The method according to claim 1, wherein the cooling medium has
a temperature in the range of about -80.degree. C. to about
-195.degree. C.
4. The method according to claim 1, wherein said cooling medium
consists essentially of nitrogen.
5. The method according to claim 1, wherein said cooling medium is
introduced in a liquid state into the chamber and is permitted to
change to a gaseous state once introduced into said chamber.
6. The method according to claim 1, wherein said metal body is an
elongated body which is continuously introduced into said chamber
through an opening in the chamber, and wherein the cooling medium
in a gaseous state is taken from the chamber and used for
pre-cooling of parts of said metal body that have yet not been
introduced into the chamber.
7. The method according to claim 1, wherein said metal body is a
wire or tube and wherein said deformation of said metal body inside
said chamber includes a reduction of a thickness of the-wire or
tube.
8. A device for generating twin lamellas in a metal body, said
device comprising: a chamber; a chamber inlet connected to a
cooling medium source; and a deformation device for deforming said
metal body, said deformation device being positioned inside said
chamber, wherein the deformation device is positioned so that the
metal body will be surrounded by said cooling medium in a gaseous
state while being deformed by said deformation device.
9. The device according to claim 8, further comprising temperature
control means for controlling the temperature inside said chamber
by controlling the introduction of cooling medium into the
chamber.
10. The device according to claim 9, wherein said temperature
control means includes at least a first and a second independently
controllable nozzle positioned inside the chamber and each nozzle
being configured to introduce cooling medium into the chamber,
wherein the first nozzle is configured to direct cooling medium
directly onto the metal body during deformation, and wherein the
second nozzle is configured to direct cooling medium onto the
deformation device during deformation.
11. The device according to claim 10, wherein said metal body is an
elongated body, and further comprising means for continuous
introduction of said metal body into the chamber.
12. The device according to claim 11, wherein the means for
continuous introduction of said metal body into the chamber is at
least one drawing block positioned inside the chamber, wherein the
first nozzle is configured to direct cooling medium directly onto
the metal body being wound onto the drawing block, and wherein the
second nozzle is configured to direct cooling medium onto an inner
wall of the drawing block.
13. The device according to claim 11, further comprising a channel
through which said elongated metal body is continuously introduced
into the chamber, said chamber having an outlet through which
cooling medium in a gaseous state is permitted to leave the chamber
and be introduced into said channel for pre-cooling said metal body
before the body is introduced into the chamber.
14. The device according to claim 8, wherein said chamber is a
generally closed chamber, and wherein the device further comprises
means for controlled evacuation of cooling medium in a gaseous
state from said chamber.
15. The device according to claim 8, wherein said cooling medium
source is a liquid nitrogen source.
16. The device according to claim 8, wherein said metal body is a
wire or tube and said deformation device includes at least one die
for reduction of a diameter of the wire or tube.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method of generating twin
lamellas in a metal body, comprising the steps of introducing said
metal body into a chamber, filling said chamber with a cooling
medium having a temperature that will enable generation of twin
lamellas in the metal body upon deformation thereof, and deforming
said metal body while the latter is surrounded by said cooling
medium.
[0002] The present invention also relates to a device for
generating twin lamellas in a metal body, said device comprising a
chamber, a chamber inlet connected to a cooling medium source, and
a deformation device for deforming said metal body, said
deformation device being positioned inside said chamber.
BACKGROUND
[0003] Deformation of metal, in particular wire drawing, in
cryogenic media has been suggested by prior art for the purpose of
enabling the formation of so called twin lamellas in the metal that
is deformed. Twin lamellas are formed through a phenomenon known as
"nano-twinning," in which, during deformation, the atomic
arrangements in adjacent crystalline regions of a material, such as
a metal, form mirror images of one another. These nano-twins, or
twin lamellas, are formed when the material undergoes plastic
deformation at cryogenic temperatures. Liquid nitrogen has been
suggested as a suitable cooling means. Thereby, metal wire which is
subjected to a drawing operation in a die, in which the diameter of
the metal wire is reduced, is positioned in liquid nitrogen, having
a temperature of approximately -196.degree. C. At such temperature,
generation of twin lamellas in the metal wire is assumed to take
place upon deformation thereof.
[0004] However, a drawback of prior art is that the efficiency of
liquid nitrogen as a quench coolant is limited, as it will
immediately boil when in contact with a warmer object (nitrogen
boils at -195.8.degree. C. at atmospheric pressure), thus enclosing
the object in an insulating nitrogen gas. Another drawback is that
there is a lack of possibility of adjusting the cooling temperature
depending on the deformation conditions and the material to be
deformed.
[0005] It is therefore an aspect of the present invention to
suggest an alternative method and device for generating twin
lamellas in a metal body which method provides improvement of the
possibility of adjusting the cooling temperature applied to the
metal body being deformed.
SUMMARY
[0006] The aspect of the present disclosure is obtained by means of
a method of generating twin lamellas in a metal body, comprising
the steps of [0007] introducing said metal body into a chamber;
[0008] filling said chamber with a cooling medium having a
temperature that will enable generation of twin lamellas in the
metal body upon deformation thereof; and [0009] deforming said
metal body while the latter is surrounded by said cooling medium;
wherein the cooling medium surrounding said metal body upon
deformation of the latter is in a gaseous state.
[0010] Cooling of the metal body by means of a cooling medium in a
gaseous state will improve the possibility of adjusting the
temperature of the cooling medium and, thereby, the metal body
which is being deformed. The cooling of the metal body may be
performed by using a cold gaseous medium, a gas mixed with liquid
cooling medium, a direct metal to metal coolant system, or a
combination thereof.
[0011] According to one embodiment of the method as defined
hereinabove or hereinafter, the temperature inside said chamber is
controlled by means of controlled introduction of said cooling
medium into the chamber. In other words, control of the temperature
in the chamber, and thereby of the metal body being deformed
therein, is performed through an active and purposive control of
the flow of cooling medium into the chamber.
[0012] According to one embodiment, the temperature inside the
chamber is controlled by means of controlled introduction of said
cooling medium into the chamber on at least two different locations
within the chamber, wherein the cooling medium is on a first
location directed directly onto the metal body being deformed, and
on a second location directed onto a deformation device used to
deform said metal body. Efficient cooling is thereby achieved,
since cooling medium is on one hand used to directly cool the metal
body, and on the other hand used to cool the deformation device
such that indirect cooling of the metal body can be achieved.
[0013] According to one embodiment, the cooling medium has a
temperature in the range of about -80.degree. C. to about
-195.degree. C. In other words, the cooling medium surrounding said
metal body during deformation of the latter has a temperature in
the range of about -80.degree. C. to about -195.degree. C.
According to another embodiment, the cooling medium has a
temperature in the range of about -150.degree. C. to about
-195.degree. C.
[0014] According to one embodiment, said cooling medium consists
essentially of nitrogen. According to one embodiment, essentially
is referred to as at least 50 atomic %. According to yet other
embodiments, essentially is referred to as at least 60 atomic %,
such as to at least 70 atomic %, such as to at least 80 atomic %,
such as to at least 80 atomic %, such as to at least 90 atomic
%.
[0015] According to one embodiment of the method as defined
hereinabove or hereinafter, said cooling medium may be introduced
in a liquid state into the chamber and is then, as result of the
temperature and pressure reigning in the chamber, permitted to
change to a gaseous state once introduced into said chamber. Also,
the introduction technique affects the transition into gaseous
phase. According to one embodiment, the cooling medium is sprayed
into the chamber through nozzles. Thus, the cooling medium may be
stored in liquid state, but may have its effect on said metal body
in a gaseous state. Introducing the cooling medium into the chamber
in a liquid state, as compared to introducing it in a gaseous
state, also has the advantage of resulting in a better cooling
efficiency.
[0016] According to one embodiment, said metal body is an elongated
body which is continuously introduced into said chamber through an
opening in the latter, and part of the cooling medium in a gaseous
state may be removed from the chamber and used for pre-cooling of
parts of said metal body that have yet not been introduced into the
chamber. Pre-cooling of the said metal body contributes to a more
precise temperature control thereof and improved cooling
efficiency.
[0017] According to one embodiment, said metal body is a wire or
tube and said deformation thereof inside said chamber includes a
reduction of the thickness thereof.
[0018] The above mentioned aspect of the present disclosure is also
achieved by means of a device for generating twin lamellas in a
metal body, said device comprising [0019] a chamber; [0020] a
chamber inlet connected to a cooling medium source; and [0021] a
deformation device for deforming said metal body, said deformation
device being positioned inside said chamber; wherein the
deformation device is positioned so that the metal body will be
surrounded by said cooling medium in a gaseous state while being
deformed by said deformation device.
[0022] According to on embodiment, said device comprises
temperature control means for controlling the temperature inside
said chamber by controlling the introduction of cooling medium into
the chamber. Such temperature control means for controlling the
temperature inside said chamber may include a control valve or
similar equipment arranged in a conduit connecting the cooling
medium source with said chamber inlet.
[0023] According to one embodiment, said temperature control means
comprises at least a first and a second independently controllable
nozzle positioned inside the chamber and configured to introduce
cooling medium into the chamber, wherein the first nozzle is
configured to direct cooling medium directly onto the metal body
during deformation, and wherein the second nozzle is configured to
direct cooling medium onto the deformation device during
deformation. Thus, efficient cooling through direct cooling and
indirect cooling of the metal body can be achieved. The temperature
control means may also comprise three or more independently
controllable nozzles, wherein a third nozzle is configured to
direct cooling medium into the chamber, and not directly onto the
metal body or the deformation device. If the device for generating
twin lamellas in a metal body comprises more than one deformation
device, such as two deformation devices, at least two nozzles may
be provided per deformation device, wherein the deformation devices
are configured as described above.
[0024] According to one embodiment, said metal body is an elongated
body, and said device comprises means for continuous introduction
of said metal body into the chamber. Such means for continuous
introduction of said metal body into the chamber may include any
kind of drawing equipment operating with a pulling effect on the
metal body.
[0025] According to one embodiment, the means for continuous
introduction of said metal body into the chamber is at least one
drawing block positioned inside the chamber, wherein the first
nozzle is configured to direct cooling medium directly onto the
metal body being wound onto the drawing block, and wherein the
second nozzle is configured to direct cooling medium onto an inner
wall of the drawing block. Direct and indirect cooling, by heat
transfer metal to metal of the metal body is thereby achieved
during drawing. This is in the present disclosure also referred to
as a direct metal to metal coolant system. The at least one drawing
block may in this case form part of the deformation device, which
may be in the form of e.g. a drawing machine.
[0026] According to one embodiment, said device comprises a channel
through which said elongated metal body is continuously introduced
into the chamber, and the chamber has an outlet through which
cooling medium in a gaseous state is permitted to leave the chamber
and be introduced into said channel for the purpose of pre-cooling
said metal body before the latter is introduced into the
chamber.
[0027] According to one embodiment, said chamber is a generally
closed chamber, and the device comprises means for controlled
evacuation of cooling medium in a gaseous state from said chamber.
Said means for controlled evacuation may include a control valve or
similar equipment. A closed chamber is referred to as a chamber
having a limited space which space is large enough for housing the
essential parts of a deformation device by means of which said
metal body is deformed in said chamber, but the space is yet small
enough for enabling efficient cooling of the metal body therein
with a low consumption of cooling medium. According to one
embodiment, the volume, V, of said chamber is below 5 m.sup.3,
according to another embodiment, V is below 3 m.sup.3, and
according to yet another embodiment, V is below 2 m.sup.3.
[0028] According to one embodiment, said cooling medium source is a
liquid nitrogen source.
[0029] According to one embodiment, said metal body is a wire or
tube and said deformation device comprises at least one die for
reduction of the diameter of the wire or tube.
[0030] Further features and advantages of the present disclosure
will appear from the following detailed description, presented with
reference to the annexed drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Hereinafter, by way of example, the method and the device of
the present disclosure will be described more in detail with
reference to the annexed drawing on which:
[0032] FIG. 1 is a schematic representation of a device according
to the disclosure, and
[0033] FIG. 2 shows the device of FIG. 1 in a view from above,
[0034] FIG. 3 is a cross section of a part of the device, taken
along III-III in FIG. 1,
[0035] FIG. 4 is an end view of a part of the device, according to
Iv-Iv in FIG. 1,
[0036] FIG. 5 is a schematic representation of parts of a device
according to the disclosure, and
[0037] FIG. 6 is a schematic representation of parts of a device
according to the disclosure.
DETAILED DESCRIPTION
[0038] FIGS. 1 and 2 show a device according to the present
disclosure for generating twin lamellas in a metal body 1, said
device comprising a chamber 2, a chamber inlet 3 connected to a
cooling medium source 4, a deformation device 5 for deforming said
metal body 1, said deformation device 5 being positioned inside
said chamber 2, wherein the deformation device 5 is positioned so
that the metal body Twill be surrounded by said cooling medium in a
gaseous state while being deformed by said deformation device
5.
[0039] The device according to the present disclosure as presented
in FIGS. 1 and 2 includes further means 6 for controlling the
temperature inside said chamber 2 by controlling the introduction
of cooling medium into the chamber 2. Here, said means 6 for
controlling the temperature inside the chamber 2 includes a control
valve 6 positioned in a conduit 7 which connects the cooling medium
source 4 with the chamber 2 through the chamber inlet 3 and by
means of which control valve 6 the cooling medium flowing towards
the chamber 2 is controlled. There may be temperature sensors (not
shown) that sense the temperature inside the chamber 2 and on the
basis of which the control valve 6 is controlled.
[0040] Said chamber 2 is a generally closed chamber, at least
during operation thereof, with a volume V of about 1.5 m.sup.3,
wherein the device comprises means 8 for controlled evacuation of
cooling medium in a gaseous state from said chamber 2. Here, said
means 8 for controlled evacuation of cooling medium includes a
control valve 8. The device includes a chamber outlet 9 and a
channel 10 leading from said chamber outlet 9. The control valve 8
is positioned in said conduit 10. It should be emphasized that the
control valve 8 is optional. The flow of cooling medium through the
chamber 2 and through the channel 10 could be controlled solely by
means of one or more valves, such as the previously mentioned valve
6, for controlling the flow of cooling medium from the cooling
medium source 4 to the chamber 2.
[0041] In the embodiment shown in FIGS. 1-4, the metal body 1 is an
elongated body, and said device comprises means for continuous
introduction of said metal body into the chamber 2. The elongated
metal body 1 is a wire, the diameter of which is to be reduced by
the deformation device 5. It should be noted that the metal body 1
could, alternatively, be a tube. The deformation device 5 comprises
a drawing machine 5 provided inside the chamber 2. Here, the
drawing machine 5 comprises a first drawing block 12 and a second
drawing block 13, a first die 14 and a second die 15. The drawing
blocks 12, 13 have a pulling effect on the elongated metal body 1
and thereby form said means for continuous introduction of the
elongated metal body 1 into the chamber 2. The dies 14, 15 are used
for reducing the diameter of the elongated metal body 1 as the
latter is pulled through the respective die 14, 15. The drawing
blocks 12, 13 and the respective dies 14, 15 are arranged in
series, such that the first drawing block 12 pulls the elongated
metal body 1 through the first die 14 and the second drawing block
13 pulls the elongated metal body 1 through the second die 15. It
should, however, be noted that other possible arrangements of
drawing blocks and dies are possible within the scope of protection
claimed for the present disclosure. For example, there may be only
one die provided, or no die at all. In the latter case, the wire
diameter is reduced as the metal body (wire) 1 is drawn between two
drawing blocks. It is thus to be understood that what has
heretofore been stated for embodiments including double drawing
blocks is also applicable for embodiments in which there is only
one drawing block present or embodiments in which there are more
than two drawing blocks present. The deformation process may not
even be a diameter reduction process but any other possible
deformation process, such as bending, by means of which twin
lamellas is to be formed in a metal body as the metal body is
subjected to said deformation at a sufficiently low
temperature.
[0042] FIGS. 3 and 4 show a cross section and an end view
respectively of a part of the device including one of said drawing
blocks 12, 13. The respective drawing block 12, 13 is carried by a
respective shaft 16, 17 that penetrates a rear wall 18 of the
chamber 2 and is driven by a respective motor 19, 20 provided
outside the chamber 2. Power transmission parts 21, 22, such as
gear wheels (not shown in detail), which may need lubrication by
means of a lubricant and through which power is transmitted from
the respective motor 19, 20 to the associated shaft 16, 17 are
provided outside the chamber 2. Subjection of such parts to the
temperatures attained inside the chamber 2 during operation of the
device is thereby avoided. The drawing blocks 12, 13 and the
respective shafts 16, 17 that carry them are horizontally arranged.
Suspension arrangements 31, 32 carrying the respective drawing
block 12, 13 and their associated shafts 16, 17 and transmission
parts 21, 22 are also provided outside the chamber 2. Said
suspension arrangements 31, 32 comprise bearings enabling rotation
of rotatable parts such as said shafts in relation to stationary
parts of the device.
[0043] As can be further seen in FIGS. 3 and 4, a front wall 23 of
the chamber 2 may be opened by means of a power device 24, here a
mechanically operated screw device. As an alternative, the power
device 24 could be a hydraulically driven arm. Thereby, access to
the inside of the chamber 2 is enabled. The walls defining the
chamber 2 are arranged as double walls with a heat insulating
material (not shown in the drawing) positioned therebetween, for
the purpose enabling maintenance of low temperature inside the
chamber 2 and avoiding excessive use of cooling medium.
[0044] FIG. 5 illustrates an embodiment of the provision of cooling
medium from the cooling medium source 4 to the chamber 2. The
cooling medium consists of nitrogen stored in the cooling medium
source 4 in liquid state. Downstream the control valve 6, which is
the main control valve, the conduit 7 from the cooling medium
source 4 to the chamber 2 is subdivided in a number of branches,
here three branches 33, 34, 35. A first branch 33 leads to a first
nozzle 36 or opening through which the cooling medium is introduced
into the chamber 2 in the region of the first drawing block 12 and
the first die 14. A second branch 34 leads to a second nozzle 37 or
opening through which the cooling medium is introduced into the
chamber 2 in the region of the second drawing block 13 and the
second die 15. It should be understood that there could be other
alternative provisions of conduit branches and nozzles as well as
alternative positioning thereof. A third branch 35 leads to the
first die 14 and the second die 15 for the purpose of providing
cooling medium to the respective die 14, 15 for the cooling thereof
during operation. In each branch 33, 34, 35, there is provided a
control valve 38, 39, 40 for controlling the flow of cooling medium
therein. In the conduit 7, downstream the main control valve 6 and
upstream the respective branch 33, 34, 35, there is provided a
purge valve 41.
[0045] FIG. 6 illustrates another embodiment of the provision of
cooling medium to the chamber 2 via the first branch 33, previously
described with reference to FIG. 5. Downstream of the control valve
38, three more control valves 42, 43, 44 are provided, and
additionally two more nozzles 45, 46. The control valve 42 is used
to control the flow of cooling medium to the first nozzle 36,
providing general cooling of the chamber 2 by emitting cooling
medium into the chamber 2 in front of the first drawing block 12.
The control valve 43 is used to control the flow of cooling medium
to the nozzle 45, which is configured to direct cooling medium onto
the metal body 1 as it is being wound onto the first drawing block
12. The control valve 44 controls the flow of cooling medium to the
nozzle 46, which is configured to direct cooling medium onto an
inside of the drawing block 12, thus indirectly cooling the metal
body 1 via the drawing block 12. Of course, a corresponding
provision of cooling medium via several nozzles and control valves
may be arranged to the second drawing block 13 via the second
branch 34.
[0046] In addition to the parts of the device mentioned above, the
embodiment of the device of the present disclosure shown in FIGS.
1-4 further comprises an uncoiling plate 25 on which a wire coil 26
is positioned and uncoiled through a rotation of the uncoiling
plate 25. The elongated metal body 1, here being described by said
wire, extends from said uncoiling plate 25 to rectifier device 27
for straightening of the wire. Before entering the chamber 2, the
metal body (the wire) 1 extends into the same channel 10 as is used
for evacuation of gaseous cooling medium from the chamber 2. In
said channel 10, the metal body (the wire) 1 is pre-cooled before
entering the chamber 2 through the previously mentioned chamber
outlet 9. The metal body 1 extends through the respective die 14,
15 of the deformation device 5, thereby being pulled by the
respective drawing block 12, 13. Downstream the chamber 2 with its
deformation device 5, there is provided a heating device 28 aimed
for heating the metal body 1 as the latter passes through said
heating device 28. Downstream the heating device 28, there is
provided a printer 29 registering the speed with which metal body 1
passes it. Downstream the printer 29, there is provided a bending
coiler 30 which winds the metal body 1, i.e. the wire, into a
coil.
[0047] Although not shown in the drawing, there may be provided a
fan inside the chamber 2, by means of which gaseous cooling medium
inside the chamber is set into motion. An improved cooling effect
on the metal body 1 is thereby achieved as the convection is
increased.
* * * * *