U.S. patent application number 13/926639 was filed with the patent office on 2013-10-31 for method for repairing metallic structure.
The applicant listed for this patent is Richard F. Kral, Shane A. Mayhill, David P. Workman. Invention is credited to Richard F. Kral, Shane A. Mayhill, David P. Workman.
Application Number | 20130284706 13/926639 |
Document ID | / |
Family ID | 44655208 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130284706 |
Kind Code |
A1 |
Kral; Richard F. ; et
al. |
October 31, 2013 |
Method for Repairing Metallic Structure
Abstract
A rail repair method enables repair of rails and rail-like
structures. A rail defect is initially identified and removed as
contained within a volumetric material portion so as to form a
contoured void while maintaining continuity of the rail opposite
the void. A pre-formed insert is then placed into the void thereby
effecting a rail-to-insert interface. Current is driven through the
interface as force directs the insert against the rail. Resistance
heat and pressure weld the insert to the rail. The flash welding
aspects remove oxides and other impurities from the interface, and
the forge welding aspects create a robust solid state weld. Excess
material, whether flash, rail, or insert-based, is removed during
the finishing processes to provide a virtually seamless rail
repair. The solid state weld repair methodology may be used to
repair any number of targeted metallic rail-like structures.
Inventors: |
Kral; Richard F.; (North
Riverside, IL) ; Mayhill; Shane A.; (Crete, IL)
; Workman; David P.; (Dublin, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kral; Richard F.
Mayhill; Shane A.
Workman; David P. |
North Riverside
Crete
Dublin |
IL
IL
OH |
US
US
US |
|
|
Family ID: |
44655208 |
Appl. No.: |
13/926639 |
Filed: |
June 25, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12661965 |
Mar 26, 2010 |
|
|
|
13926639 |
|
|
|
|
Current U.S.
Class: |
219/55 ;
29/402.07 |
Current CPC
Class: |
B23P 6/00 20130101; B23K
11/004 20130101; E01B 31/18 20130101; Y10T 29/49728 20150115; E01B
29/42 20130101; B23K 11/34 20130101; B23K 2101/26 20180801; B23K
11/0013 20130101 |
Class at
Publication: |
219/55 ;
29/402.07 |
International
Class: |
B23K 11/00 20060101
B23K011/00; E01B 29/42 20060101 E01B029/42 |
Claims
1. A method of repairing a metallic structure having first and
second structural sections, the method comprising the steps of: a)
identifying and locating a defect in the metallic structure; b)
removing a volumetric portion from the first structural section,
the volumetric portion being inclusive of the defect; c) exposing a
void site in the first structural section via removal of the
volumetric portion; d) placing a pre-formed, solid state weld
repair insert into the void site, thereby effecting a
structure-to-insert interface; and e) welding the metallic
structure and insert at the structure-to-insert interface.
2. The method of claim 1 wherein the welding step comprises the
step of driving current through the structure-to-insert
interface.
3. The method of claim 1 comprising the step of maintaining
continuity of the second structural section while exposing the void
site.
4. The method of claim 3 wherein the volumetric portion has a first
volume and the insert has a second volume greater in magnitude
relative to the first volume.
5. The method of claim 4 comprising the step of forcing the insert
against the metallic structure during the welding process.
6. The method of claim 5 comprising the step of removing oxides
from the structure-to-insert interface during the welding
process.
7. The method of claim 6 comprising the step of interdiffusing
atomic structure from the metallic structure and insert across the
structure-to-insert interface.
8. The method of claim 7 wherein the metallic structure is a
rail.
9. A method of repairing a current-conductive rail, which rail
includes upper and lower rail sections, the method comprising the
steps of: a) identifying and locating a defect in a first select
rail section, the first select rail section being selected from the
group consisting of the upper and lower rail sections; b) removing
a volumetric portion of the rail from the first select rail
section, the volumetric portion being inclusive of the defect; c)
exposing a void site in the first select rail section via removal
of the volumetric portion; d) placing a pre-formed
current-conductive insert into the void site, thereby effecting a
rail-to-insert interface; e) driving current through the
rail-to-insert interface; f) resistance-heating the rail and insert
at the rail-to-insert interface via the driven current; and g)
welding the insert to the rail.
10. The method of claim 9 comprising the step of maintaining
continuity of a second select rail section while exposing the void
site, the second select rail section being selected from the group
consisting of the upper and lower rail sections and being other
than the first select rail section.
11. The method of claim 10 wherein the volumetric portion has a
first volume and the insert has a second volume greater in
magnitude relative to the first volume.
12. The method of claim 11 wherein the void site has a maximal
transverse cross-sectional site area and the insert has a maximal
transverse cross-sectional insert area, said insert area being
greater in magnitude than said site area.
13. The method of claim 9 comprising the step of forcing the insert
against the rail while driving current through the rail-to-insert
interface.
14. The method of claim 9 comprising the step of removing oxides
from the rail-to-insert interface.
15. The method of claim 13 comprising the step of interdiffusing
atomic structure of the rail and insert across the rail-to-insert
interface.
16. The method of claim 12 wherein said insert area is minimized
relative to said site area.
17. A method of repairing a current-conductive rail, said method
comprising the steps of: a) removing a defect-inclusive, volumetric
rail portion from said rail; b) exposing a void site in said rail
via removal of said rail portion; c) placing a pre-formed
current-conductive insert into the void site, thereby effecting a
rail-to-insert interface; and d) driving current through the
rail-to-insert interface, thereby heating the rail and insert at
the rail-to-insert interface and welding the insert to the
rail.
18. The method of claim 17 comprising the step of maintaining
continuity of the rail adjacent the void site while exposing the
void site.
19. The method of claim 18 comprising the step of forcing the
insert against the rail while driving current through the
rail-to-insert interface, thereby a. removing oxides from the
rail-to-insert interface; and b. interdiffusing atomic structure of
the rail and insert across the rail-to-insert interface.
20. A rail repair method, the method comprising the steps of:
forming a wedge-shaped repair insert having a pointed rail-opposing
portion, the pointed rail-opposing portion having opposed planar
insert surfaces, the opposed planar insert surfaces being
substantially orthogonal to one another; forming a wedge-shaped
void in a rail, the void having a pointed, insert-receiving notch,
the pointed insert-receiving notch having opposed planar void site
surfaces, the void site surfaces being substantially orthogonal to
one another; inserting the wedge-shaped repair insert into the
wedge-shaped void thereby effecting an angled rail-to-insert
interface, the angled rail-to-insert interface thus having a 90
degree angle; and driving current through the rail-to-insert
interface for heating and welding the rail and insert at the
rail-to-insert interface, the 90 degree angle for enhancing uniform
heat distribution and minimizing material entrapment during the
welding process.
21. The method of claim 20 wherein the current driving step
comprises the steps of: preheating the rail and repair insert by
driving a first range of current therethrough; flashing the rail
and repair insert by driving a second range of current
therethrough; and forging the rail and repair insert by driving a
third range of current therethrough.
22. The method of claim 21 wherein the repair insert forming step
comprises the added step of forming a beveled tip intermediate the
opposed planar insert surfaces and the void forming step comprises
the added step of forming a beveled valley intermediate the opposed
planar void site surfaces, the beveled tip and beveled valley for
further minimizing material entrapment during the welding
process.
23. A method of repairing a metallic structure, the method
comprising the steps of: a) identifying and locating a defect in
the metallic structure; b) removing a volumetric portion from first
and second structural sections of the metallic structure, the first
structural section being integrally formed to the second structural
section, the volumetric portion being inclusive of the defect; c)
exposing a void site in the first and second structural sections
via removal of the volumetric portion; d) placing a pre-formed,
solid state weld repair insert into the void site, thereby
effecting a structure-to-insert interface, the insert comprising an
insert volume greater in magnitude than the removed volumetric
portion; and e) welding the metallic structure and insert at the
structure-to-insert interface.
24. The method of claim 23 comprising the steps of forcing the
insert toward the first and second structural sections for forging
the insert to the metallic structure at the structure-to-insert
interface while welding the metallic structure and insert at the
structure-to-insert interface.
25. The method of claim 24 wherein the volumetric portion and
insert volume are T-shaped in a first dimension, triangular in a
second dimension, and rectangular in a third dimension.
26. The method of claim 25 wherein the T-shaped volumetric portion
comprises rounded upper edging and the T-shaped insert volume
comprises right-angled upper edging.
27. The method of claim 26 wherein the triangular volumetric
portion and the insert volume each comprise a rounded interface
vertex.
28. A method of repairing a current-conductive rail, which rail
includes upper and lower rail sections, the method comprising the
steps of: a) identifying and locating a defect in a first select
rail section, the first select rail section being selected from the
group consisting of the upper and lower rail sections; b) removing
a volumetric portion of the rail from the first select rail
section, the volumetric portion being inclusive of the defect; c)
exposing a void site in the first select rail section via removal
of the volumetric portion; d) placing a pre-formed
current-conductive insert into the void site, thereby effecting a
rail-to-insert interface, the insert comprising an insert volume
greater in magnitude than the removed volumetric portion; e)
driving current through the rail-to-insert interface; f)
resistance-heating the rail and insert at the rail-to-insert
interface via the driven current; and g) welding the insert to the
rail.
29. The method of claim 28 comprising the steps of forcing the
insert toward the upper and lower rail sections for forging the
insert to the rail at the rail-to-insert interface while welding
the insert to the rail.
30. The method of claim 28 wherein the volumetric portion and
insert volume are T-shaped in a first dimension, triangular in a
second dimension, and rectangular in a third dimension.
31. The method of claim 30 wherein the T-shaped volumetric portion
comprises rounded upper edging and the T-shaped insert volume
comprises right-angled upper edging.
32. The method of claim 31 wherein the triangular volumetric
portion and the insert volume each comprise a rounded interface
vertex.
33. A method of repairing a current-conductive rail, said method
comprising the steps of: a) removing a defect-inclusive, volumetric
rail portion from upper portions of said rail; b) exposing a void
site in said rail via removal of said rail portion; c) placing a
pre-formed current-conductive insert into the void site, thereby
effecting a rail-to-insert interface, the insert comprising an
insert volume greater in magnitude than the removed volumetric
portion; and d) driving current through the rail-to-insert
interface, thereby heating the rail and insert at the
rail-to-insert interface and welding the insert to the rail.
34. The method of claim 33 comprising the steps of forcing the
insert toward the upper portions for forging the insert to the rail
at the rail-to-insert interface while welding the insert to the
rail.
35. The method of claim 33 wherein the volumetric portion and
insert volume are T-shaped in a first dimension, triangular in a
second dimension, and rectangular in a third dimension.
36. The method of claim 35 wherein the T-shaped volumetric portion
comprises rounded upper edging and the T-shaped insert volume
comprises right-angled upper edging.
37. The method of claim 36 wherein the triangular volumetric
portion and the insert volume each comprise a rounded interface
vertex.
38. A rail repair method, the method comprising the steps of:
forming a wedge-shaped repair insert, the insert being T-shaped in
a first dimension, triangular in a second dimension, and
rectangular in a third dimension, the triangular second dimension
having a pointed rail-opposing portion, the pointed rail-opposing
portion having opposed planar insert surfaces, the opposed planar
insert surfaces being substantially orthogonal to one another;
forming a wedge-shaped void in a rail, the void being T-shaped in
the first dimension, triangular in the second dimension, and
rectangular in the third dimension, the void having a pointed,
insert-receiving notch, the pointed insert-receiving notch having
opposed planar void site surfaces, the void site surfaces being
substantially orthogonal to one another; inserting the wedge-shaped
repair insert into the wedge-shaped void thereby effecting an
angled rail-to-insert interface, the angled rail-to-insert
interface thus having a 90 degree angle; and driving current
through the rail-to-insert interface for heating and welding the
rail and insert at the rail-to-insert interface, the 90 degree
angle for enhancing uniform heat distribution and minimizing
material entrapment during the welding process.
39. The method of claim 38 comprising the steps of forcing the
insert toward the rail for forging the insert to the rail at the
rail-to-insert interface while welding the insert to the rail.
40. The method of claim 38 wherein the T-shaped dimension of the
insert comprises right-angled upper edging, and the T-shaped
dimension of the void comprises rounded upper edging.
41. The method of claim 40 wherein the triangular dimension of the
insert and void each comprise a rounded interface vertex.
Description
PRIOR HISTORY
[0001] This non-provisional patent application is a divisional
patent application of pending U.S. patent application Ser. No.
12/661,965 filed in the United States Patent and Trademark Office
on 26 Mar. 2010, the specifications of which are hereby
incorporated by reference thereto.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention generally relates to a method of repairing
targeted defect-containing metallic structure, and more
particularly to a method of repairing railroad rail having a
localized defect in the top portion of the rail, which methodology
involves the step of removing a defect-containing top portion of
the rail, replacing the removed portion of the rail by welding in a
solid state weld repair insert.
[0004] 2. Description of Prior Art
[0005] Railroads must maintain their track to ensure safe operation
of trains. Some of this maintenance centers on the repair of rail
defects. Railroad rails may be manufactured with internal defects
or, as a result of fatigue, develop defects. These defects are
commonly located using non-destructive test methods. The Federal
Railway Administration (FRA), for example, mandates periodic
ultrasonic testing of railroad rails to locate defects in the rail.
When a defect is found, a repair must be made to the track
structure. It has been noted that many of these defects are located
in the top portion of the rail or within the rail head.
[0006] There are two common welding processes used to facilitate
the repair of defects in railroad rails. These processes are the
thermite welding process and the flash-butt welding process. Rails
repaired by a flash-butt weld are typically stronger and higher in
quality than those repaired by a thermite weld. Repairs made by the
thermite process are initially less costly, however, due to the
relatively higher labor and equipment or components cost(s)
required by the flash-butt process. Rails may also be temporarily
repaired through the use of joint bar splices. Overall rail
integrity is best maintained, however, by having the lowest number
of joints (mechanical or welded) in track.
[0007] State of the art rail repair directed at repairing defects
has typically involved removing a length of rail, (typically 13 to
19 feet in length) localized around the defect, from the existing
rail. The removal of the rail length thus creates a significant gap
in the rail. A so-called "rail plug" is then inserted in the
resulting gap to make up for the bulk of the rail length removed. A
weld is then made at each end of the rail plug, welding the rail
plug to the existing rail, and creating a continuously welded
rail.
[0008] A thermite weld can be used to weld the existing rail to the
rail plug. A rail plug is cut to a length approximately two inches
shorter than the length of the rail containing the defect, which is
being cut out. The repair plug is placed into the gap. A sand mold
is attached to both the existing rail and the rail plug around an
approximate one-inch gap between the end of the existing rail and
the end of the rail plug. The thermite material is contained in a
crucible located immediately above the sand mold. After the mold is
pre-heated, the thermite charge is ignited. The thermite charge
creates molten steel, which pours into the sand mold.
[0009] As the thermite material solidifies, it forms a casting,
which bonds to, and is contiguous with, both the existing rail and
the rail plug. In this manner, the rail plug is welded to the
existing rail to form a continuous section. A second thermite weld
is made at an approximate one-inch gap at the opposite end of the
rail plug, joining the rail plug to the existing rail. The area of
the rail containing the thermite weld material is not as strong as
and is not of the same quality as normal rail steel. As such, the
thermite welds typically require subsequent repairs in order to
maintain the railroad rail in safe condition. This method also
requires the repair crew to transport a rail plug to the repair
site and the section of rail containing the defect away from the
site.
[0010] A flash-butt weld can also be used to weld the existing rail
to the rail plug. A rail plug is cut to a length approximately
three inches longer than the length of the rail containing the
defect, which is being cut out. Rail anchors are removed from the
existing rail until the gap created by the removal of the defect
containing rail plug is three inches longer than the defect
containing rail plug. This can only occur when the current rail
temperature (CRT) is below the neutral rail temperature (NRT). The
rail plug is put in to the gap created by the removal of the defect
containing rail plug and gap growth created by the removal of
anchors.
[0011] The rail ends to be welded are aligned. A flash-butt weld
welderhead is clamped across the abutment of the rail plug and the
existing rail, and the flash-butt welding cycle is carried out. The
welderhead passes a high current across the interface between the
existing rail and the rail plug. The current produces arcing
between the mating surfaces. As the cycle progresses and sufficient
heat has been generated, the welderhead forges the two pieces of
rail together to essentially form a single continuous rail. A shear
die is then pushed across the weld to return the weld profile to
the rail contour. The flashing away of the rail and the forging of
the rail consume about one and one half inches of rail from the
rail and the rail plug.
[0012] The rail ends at the other end of the rail plug are aligned.
The flash-butt welderhead is moved to the other end of the rail
plug and clamped across the abutment of the rail plug and the
existing rail. The rails are stretched to close the gap (which was
generated by the making of the initial weld and subsequent moving
the rail plug) and the flash-butt weld cycle is carried out. Rail
anchors are then replaced on to the existing rail. As such, the
flash-butt welding process is typically more costly than the
thermite process. This method also requires the repair crew to
transport a rail plug to the repair site and the section of rail
containing the defect away from the site.
[0013] Regardless of the repair weld process used, there is a need
to maintain the NRT. The NRT is the temperature at which the rail
contains no longitudinal thermally-induced rail stresses. The track
is designed to not allow the rails to contract and expand in
response to environmental temperature changes. It is designed to
constrain the rail and allow the rail to develop tension and
compression. The amount of tension or compression is determined, in
part, by the difference between NRT and the CRT.
[0014] When a repair is accomplished by installing a rail plug, it
is unlikely that the rail plug installed will be of the exact
length necessary to maintain the NRT of the rail, and the NRT of
the rail is thus altered. As such, the segment will have a
different NRT than desired. Notably, management of the NRT could be
simplified if no rail length is removed during the repair of a
defect in the rail.
[0015] It is further noted that when rail plugs are installed using
either the thermite weld or the flash-butt weld processes, the rail
is taken out of service. Thermite welding and flash-butt welding
trucks need to occupy the track. This prevents the railroad from
running revenue-producing trains. The installation of a rail plug
and the resulting two necessary welds uses valuable track time and
this repair time needs to be kept to a minimum.
[0016] Joint bar splices are, essentially, reinforcing clamp means
applied to the rail adjacent to the repair. A joint bar splice is
used when there is not enough time to perform a complete repair by
welding or when other repair materials are not available. A joint
bar splice, by government regulation, is a temporary repair and
must be replaced in about 90 days. The joint bar splice thus
reduces the operational limit of the rail in the repair area.
[0017] U.S. Pat. No. 7,520,415, which issued to Kral et al.
discloses a further Method of Repairing Rail, which disclosure
attempted to address the noted rail repair shortcomings. The '415
Patent describes a system or method comprising at least the
following steps: identifying and locating a defect in the rail,
removing the defect by removing material from the rail surrounding
the defect in at least the head section so as to form a void and a
rail void interface while maintaining continuity of the rail,
filling the void with molten metal having a high carbon content and
causing the molten metal and the rail void interface to bond.
[0018] The molten metal may be produced by gas shielded arc
welding. The carbon content of the molten metal is near that of the
rail to decrease carbon migration from the rails. High carbon
welding electrode is used in the welding of high strength steel
using gas shielded arc welding techniques whereby a plurality of
beads of molten weld material join together rail ends or fill a
slot in a rail for repair purposes. The high carbon electrode
avoids producing adjacent soft and brittle areas across a weld
fusion line, which results from migration of carbon from the carbon
rich high strength steel to the lower carbon and highly alloyed
weld deposit.
[0019] The foregoing methodology described by Kral et al., while
notably superior to certain aspects of the thermite and flash-butt
rail repair/welding techniques described hereinabove, nevertheless
also suffers from certain shortcomings. In this regard, it is noted
that the molten metal material is a dynamically active medium,
which medium presents certain difficulties in (non-ideal)
application scenarios. For example, if the rail is inclined in the
field, the molten pool of material becomes difficult to manage, and
a proper weld is often problematic to achieve without much ado.
[0020] The prior art thus perceives a need for a rail repair method
that results in a rail repair having the strength and quality of
the parent rail, but without adding or consuming rail. Further, the
prior perceives a need for a rail repair method which reduces the
total number of welds in the remaining rail. Still further, the
prior art perceives a need for a rail repair method which reduces
the amount of materials and equipment that must be transported to
and from the repair site.
[0021] Other prior art needs include a need for a rail repair
method that eliminates the use of temporary joint bar splices. The
prior art further perceives a need for a rail repair method that
does not necessitate the relatively costly and time-consuming
removal of a section of rail. The present invention attempts to
address the foregoing by providing a cost effective, time-efficient
rail repair method which minimizes the amount of time that the rail
is out of service to revenue-producing trains, and which method
greatly reduces the manpower otherwise required to effect state of
the art type repairs.
SUMMARY OF THE INVENTION
[0022] The noted needs, and others, are satisfied by the disclosed
method, which provides for repairing a rail or rail-like structure
having a defect using a single weld. The repair method according to
the present invention begins when a rail defect is identified and
located, often via use of an ultrasonic rail-testing car.
Ultrasonic rail-testing is an exemplary method and/or means that
can precisely locate and mark the area of the rail containing the
defect, and can confirm that the defect is totally contained in the
top portion of the rail head. Additionally, manual testing of the
defect may further delineate the areas of the rail that contains
the defect. The top portion of the rail is then removed and the
resulting section is filled by resistance welding a metal insert
into the void created for defect removal.
[0023] To accomplish the repair, the top portion of the rail
containing the defect is accurately identified and/or located by
any number of means. A specialized apparatus is then clamped to the
rail, and utilizing the apparatus, a volumetric top portion of the
rail containing the defect is removed. It is contemplated that the
removal may be preferably accomplished by machining away a portion
of the rail, for example, but other methods may be used.
[0024] Because only the top portion of the rail containing the
defect is removed, there is no appreciable change in the length of
the rail and the NRT remains unaffected. Because of the clamping
action of the apparatus and the fact that only the top portion of
the rail is removed, there is no need to accurately align two
rails. The rail is held in acceptable alignment by the lower
portion of the rail.
[0025] The welding head is then clamped to the rail. A pre-formed,
solid state, weld repair insert is installed in the welding head
and brought into position directly over the machined notch or void
site. The insert is pre-machined from high quality steel that is
compatible to the rail steel. The resistance welding cycle is then
initiated. The welding current and platen (insert) position are
precisely controlled to first preheat the rail and insert and then
flash clean the surfaces to be welded. Finally, the insert is
forged in to the rail to create the welding bond.
[0026] Because the rail repair is accomplished without using a rail
plug, there is no need to transport rail plugs to or away from the
repair site. Additionally, the NRT of the original rail is
maintained as no additional rail or materials are or even can be
added or removed from the existing rail length. Because only a
single weld is required, and the insertion of a rail plug is not
required (as compared to other prior methods requiring two welds
and plug exchange), the disclosed repair method is more time
efficient than prior repair methods.
[0027] Given that the repair method is typically faster and does
not require additional rail or materials, this method of repair can
be performed instead of using a joint bar splice. The repair can be
accomplished in the same track occupation as required by the
detector car, thereby allowing more time of the running of
revenue-producing trains. Moreover, the material characteristics
and the process used to deposit the fill material can provide a
repair structure which has the properties equaling those of the
rail material and far surpassing those of the thermite weld.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Other features of our invention will become more evident
from a consideration of the following brief description of patent
drawings:
[0029] FIG. 1 is a side elevational view of a fragmentary rail
length having a defect in the rail head as generically marked with
an "X".
[0030] FIG. 1(a) is transverse sectional view of the rail length
otherwise depicted in FIG. 1 as sectioned through the defect.
[0031] FIG. 2 is a side elevational view of a fragmentary rail
length having a defect in the rail head as marked at "X", which
defect is being identified and located via certain generic
defect-locating means.
[0032] FIG. 3 is a side elevational view of a fragmentary rail
length having a defect in the rail head as marked at "X", which
defect has been targeted for removal as contained within a
volumetric upper rail portion as depicted with broken lines.
[0033] FIG. 4 is a side elevational view of a fragmentary rail
length showing the marked volumetric upper rail portion otherwise
depicted in FIG. 3 being removed.
[0034] FIG. 4(a) is an enlarged fragmentary view as sectioned from
FIG. 4 depicting the angled surfaces of the void site with a
beveled valley therebetween.
[0035] FIG. 5 is a longitudinal or axial view of a rail length as
supported by generic support structure, and engaged with certain
elements of a rail bus assembly in inferior adjacency to certain
elements of an insert bus assembly as outfitted with a repair
insert.
[0036] FIG. 6 is a side elevational view of the structures
otherwise illustrated in FIG. 5, which view depicts a fragmentary
rail length as supported by generic support structure and engaged
with certain elements of rail bus assembly in inferior adjacency to
certain elements of an insert bus assembly as outfitted with a
repair insert.
[0037] FIG. 7 is a longitudinal or axial view of the structures
otherwise depicted in FIG. 5, which view depicts the rail length
engaged with certain elements of the rail bus assembly and the
repair insert, which repair insert is further engaged with certain
elements of the insert bus assembly.
[0038] FIG. 8 is a side elevational view of the structures
otherwise illustrated in FIG. 6, which view depicts the fragmentary
rail length engaged with the repair insert, which repair insert is
further engaged with certain elements of the insert bus
assembly.
[0039] FIG. 9 is a top exploded perspective view of the structural
elements otherwise depicted in FIGS. 5 and 6.
[0040] FIG. 10 is a top perspective view of the structural elements
otherwise depicted in FIGS. 5 and 6, which elements are shown in
assembled form.
[0041] FIG. 11 is a bottom perspective view of an exemplary repair
insert according to the present invention.
[0042] FIG. 12 is a side view of the exemplary repair insert
otherwise depicted in FIG. 11.
[0043] FIG. 12(a) is an enlarged fragmentary view as sectioned from
FIG. 12 depicting the angled surfaces of the repair insert with a
beveled tip therebetween.
[0044] FIG. 13 is a side view of the exemplary repair insert
otherwise depicted in FIGS. 11 and 12 as inserted into a void site
formed in a fragmentary upper rail portion before the weld cycle is
initiated.
[0045] FIG. 14 is a top view of the exemplary repair insert
otherwise depicted in FIGS. 11-13 as inserted into a void site
formed in a fragmentary upper rail portion.
[0046] FIG. 15(a) is an end view of the exemplary repair insert
otherwise depicted in FIGS. 11 and 12.
[0047] FIG. 15(b) is a longitudinal or axial view of the rail
length otherwise depicted in FIGS. 13 and 14.
[0048] FIG. 15(c) is a longitudinal or axial view of the insert and
rail structures otherwise depicted in FIGS. 13 and 14.
[0049] FIG. 16 is a side view of (1) the repair insert as inserted
into and welded to the void site after the weld cycle has
completed, and (2) a generic shear die cutting element removing
excess insert, rail, and flash material from the fragmentary rail
length.
[0050] FIG. 17 is a side elevational view of a fragmentary rail
length having a finished repair site, which repair site is marked
with thin broken lines.
[0051] FIG. 18 is an enlarged fragmentary diagrammatic depiction of
the rail-to-insert interface having an exaggerated gap and showing
orthogonally opposed planes of the interface extending from a
beveled junction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT/METHODOLOGY
[0052] Referring now to the drawings with more specificity, the
reader is directed to FIG. 1, which figure depicts a side
elevational view of a fragmentary rail section or length as
referenced at 10. A rail length 10 is typically formed having a
rail base portion 11 with opposed flanges 12, an upstanding rail
web portion 13 extending upward from the base portion 11 between
the flanges 12, and a rail head portion 14 at the top of the rail
web portion 13 as generally and comparatively depicted in FIGS. 1
and 1(a).
[0053] The repair system or method according to the present
invention effectively begins when a rail defect 15 is identified
and located, such as by way of ultrasonic rail-testing. Ultrasonic
rail-testing can precisely locate and mark the area of rail 10
containing the defect 15. Additionally, manual testing of the
defect 15 may further delineate the areas of the rail 10 which
contain the defect 15. The ultrasonic testing, as exemplary defect
locating means, can further confirm that the defect 15 is totally
contained in the top portion or rail head 14 of the rail 10.
[0054] Further referencing FIG. 1, it will be noted that at the
upper portion or head 14 of rail section 10, a generic "X" marks a
defect spot or area as at 15. While it has been noted that a rail
defect 15 may be preferably located by ultrasonic rail testing, it
is contemplated that the rail defect 15 may be located by other
rail defect identifying or locating means such as induction means,
dye penetration means or other known methods of defect
identification.
[0055] Typically, when the ultrasonic rail testing vehicle
identifies a defect, it will mark the defect location. The defect
location may be recorded on a map, or a nozzle may mark the rail,
for example, with paint. Alternatively, the location of the defect
may be recorded using information gathered from such sources as the
global positioning system of the network of satellites. FIG. 2
attempts to depict the step of defect identification and/or
location via generic defect identifying/locating means as
referenced at 16.
[0056] After the defect location has been identified, a repair crew
will be dispatched to the defect location. It is contemplated that
the repair crew will travel to the defect location with certain
means for removing material from the rail as well as certain means
for welding a repair insert 21 to the rail length 10. When the
repair crew arrives at the defect location, it may perform further
tests to delineate the exact size of the rail defect 15. Presuming
the defect 15 is of limited size and localized to a select rail
portion (typically the head 14), the defect 15 may be repaired
using the method according to the present invention.
[0057] In this regard, it is contemplated that the preferred
methodology includes the removal of a wedge-shaped portion 17 from
the rail length 10, which wedge-shaped portion 17 is outlined
before removal and highlighted with broken lines 18 in FIG. 3.
Notably, the wedge-shaped portion 17 includes, contains, or
surrounds the rail defect 15. It will be seen from a comparative
inspection of FIGS. 3 and 4 that the wedge-shaped portion 17 has a
depth 19 sufficient to include a transverse cross-section of (a)
the entire head 14 as well as (b) an upper portion of the rail web
13.
[0058] The wedge-shaped void or void site 20 is preferably formed
in the rail length 10 or similar other targeted metallic rail-like
structure such that the void 20 essentially defines a pointed,
insert-receiving notch orthogonally into the rail length 10 away
from the planar upper rail head surface 50. The pointed
insert-receiving notch or void site 20 preferably further comprises
orthogonally opposed planar void site surfaces as referenced at 51
such that the angle subtended intermediate the planar upper rail
head surface 50 and the planar surfaces 51 is substantially 45
degrees, which angle is generally referenced at 131 in FIG.
4(a).
[0059] It is contemplated that the wedge-shaped portion 17 may be
removed from the rail length 10 by any number of portion or
material-removing means as exemplified by certain machining means
(e.g. carbide-tipped machining means and electric discharge
machining (EDM) means) or abrasive means. The material-removing
means are operated to remove the wedge-shaped portion 17 from the
rail length 10 inclusive of the defect 15. The reader may note that
the process is somewhat akin to drilling out decayed dental
material.
[0060] The analogy holds true but for the fact that the material
removed from the rail length 10 according to the present invention
tends to be of a more pre-defined volume. In other words, whereas
the removal of (healthy) dental material is generally minimized
during the removal of decayed dental material, the volumetric
removal of the wedge-shaped portion 17 is (substantially)
pre-determined and defined to cooperate with pre-formed insert(s)
having a pre-determined volume greater in magnitude than the volume
of material removed or defined by the void site 20 as generally
depicted in FIGS. 4 and 6.
[0061] In other words, after the wedge-shaped, defect-containing
portion 17 of the rail length 10 is removed, the rail length 10 is
left with a substantially wedge-shaped void site as at 20. As
illustrated, an exemplary upper rail portion 17 of the rail length
10 is removed, which portion 17 preferably includes selected
portions of the rail head portion 14 and rail web portion 13.
Notably, the rail length 10 is not completely severed, but is still
connected opposite the void site 20 as only a select (upper)
portion 17 of the rail length 10 has been removed.
[0062] Because only the select (upper) portion 17 of the rail 10 is
removed (i.e. that portion corresponding to the volumetric material
removal) (a) there is no substantial change in the length of the
rail length 10, (b) there is no need to accurately cut rail plug
lengths as would be the case if a rail plug type repair were
practiced, and (c) the NRT is maintained. In other words, according
to the present methodology, the rail length 10, after removing the
portion 17, is held to the pre-repair length.
[0063] Following the removal of the wedge-shaped portion 17 from
the rail length 10, a volumetric, current-conductive or solid state
weld repair insert 21 is placed into the void site 20. The repair
insert 21 is preferably pre-formed from a material substantially
similar to the material construction of the rail length 10 (e.g.
1080 rail steel and hardened rail stock/steel, respectively). FIGS.
5 and 6 generally depict the repair insert 21 being aligned in
superior adjacency to the void site 20 from longitudinal and
lateral views respectively. FIGS. 7 and 8 generally depict the
repair insert 21 inserted or otherwise placed into the void site 20
as further seen in respective longitudinal and lateral views.
[0064] As generally depicted in FIGS. 14 and 15(c), it is
contemplated that the width 22 of the insert 21 at its upper
portion 26 is preferably slightly greater in magnitude than the
width 23 of the rail head 14 to compensate for slight lateral
shift(s) of the insert 21 during the ensuing welding cycle. From
the lateral views, as generally depicted in FIGS. 12 and 13, the
reader will note that the length 38 of the insert 21 is also
greater in magnitude relative to the maximum length 39 of the upper
plane of the void site 20. The reader should further note the
overall depth 19 of the insert 21 exceeds the void depth as at
24.
[0065] The wedge-shaped, solid state weld repair insert 21 is
preferably formed such that the insert 21 preferably has a pointed
rail-opposing portion as at 60 and planar force-receiving portion
as at 61. The pointed rail-opposing portion 60 thus has opposed
planar insert surfaces 62, which opposed planar insert surfaces 62
are preferably and substantially orthogonal to one another and
preferably intersecting at a beveled tip 41 or terminus.
[0066] The volume of the repair insert 21 is thus greater in
magnitude than the effective volume of the void site 20. During the
weld cycle, the material composition of the rail 10 and repair
insert 21 is consumed such that the void site 20 is effectively
filled with the material composition of the repair insert 21.
Excess material, whether excess flash material and/or excess
insert/rail material at the repair site 125, is preferably removed
from the rail length 10 following the weld and optional heat treat
processes.
[0067] FIG. 9 depicts an exploded perspective view of a test weld
scenario showing the primary components that enable the present
methodology. In this regard, the preferred system and/or method
essentially employs a current-conductive, insert-side bus assembly
for interfacing with the repair insert 21 and a current-conductive,
rail-side bus assembly for interfacing with the rail length 10.
[0068] The insert-side bus assembly preferably comprises a top bus
bar as at 30, a wedge or insert block as at 31, a pair of inner,
opposed wedge or insert side plates as at 32, a pair of outer side
plates as at 33, and a pair of cooling blocks as at 34. Cooling
blocks 34 can be moved to achieve strategic cooling of the tooling
and/or weld.
[0069] Opposite the insert-side bus assembly is positioned a
rail-side bus assembly (or assemblies). The rail length 10 is
supported in FIGS. 5-10 by a generic support plane or structure as
referenced at 102. The rail-side bus assembly preferably comprises
laterally-opposed, web-engaging rail bus elements as at 40 each of
which is engaged with (a) opposed rail bus side plates as at 41 and
(b) a rail bus bridge as at 42. FIGS. 7 and 8 depict current 100
being driven through the bus assemblies via the repair insert 21,
the rail length 10, and the structure-to-insert interface or
rail-to-insert interface 101.
[0070] A so-called flash butt weld cycle typically comprises three
phases, namely, a pre-heating phase, a flashing phase, and an
upsetting or forging phase by way of varied amperages ranging
anywhere from 22,000 amps to 47,000 amps. Excellent results, for
example, have been achieved by using an electric current during (1)
the pre-heating phase between 32,000 and 42,000 amps, (2) the
flashing phase between 27,000 and 37,000 amps, and (3) the
upsetting phase between 30,000 and 44,000 amps. The nominal
flashing voltage is best at about seven to ten volts, and the
nominal upsetting distance is best at about 0.375 to 1.00 inch. The
foregoing amperages, voltages, and distances are exemplary and not
limiting.
[0071] Resistance from the current 100 being driven through the
structures heats the interface 101, and the repair insert 21 is
thus flash-welded to the rail length 10 at the void site 20 as
generically depicted at "flashing" 105. This has the effect of
forming an oxide-free, clean junction between the repair insert 21
and the rail length 10 as the respective surfaces of the repair
insert 21 and rail length 10 are forced out the sides of the
junction or rail-to-insert interface 101. FIG. 16 depicts the
noted/described excess flash material as referenced at 104.
[0072] The reader will further note from an inspection of FIGS. 7
and 8 that a significant force 103 is directed into the structures
such that the repair insert 21 is forced against the rail length 10
at the void site (elsewhere referenced at 20). The
ensuing/attendant heat and force 103 further cause the repair
insert 21 to be forge-welded to the rail length 10 at the
rail-to-insert interface 101, during which atomic structure of the
rail length 10 and repair insert 21 interdiffuse to cause a robust,
solid-state weld at the rail-to-insert interface 101.
[0073] As earlier introduced, the reader will note that the
wedge-shaped void site 20 and wedge-shaped repair insert 21 provide
an angled rail-to-insert interface 101. It is contemplated that a
significant benefit is achieved by way of the angled rail-to-insert
interface 101. For example, the reader will note that force 103 is
directed in a first (or downward) direction as depicted in the
drawings. The angled rail-to-insert interface 101 is bound on the
rail side by rail structure along its entire length 39 for opposing
force 103 as delivered to the rail length 10 via repair insert 21.
The repair inset 21 thus transfers force 103 along that portion of
length 39 in contact with the rail length 10.
[0074] Excellent results have been achieved when forming a 90
degree angle (as at 130 in FIGS. 4(a) and 18) at the void site 20
and repair insert 21. It is contemplated that the orthogonal
relationship between opposing planes 115 of the interface 101
structurally function to enhance uniform heat distribution (as
diagrammatically depicted at 150 in FIG. 18) and minimize material
entrapment during the welding process.
[0075] Further, the valley 40 of the void site 20 and the tip 41 of
the insert 21 are preferably beveled or rounded for further
minimizing material entrapment during the welding process.
Excellent results have been achieved when the radii of curvature of
the beveled structures 40 and 41 are on the order of 0.25 inch.
Other insert geometry is believed inferior for achieving the
desired result as compared to the geometry shown in the various
illustrations.
[0076] FIGS. 11-15(a) depict the preferred geometry of the repair
insert 21. It will be recalled that before the welding cycle
begins, the repair insert 21 has a pre-determined geometry such
that the upper width 22 of the repair insert 21 is of slightly
greater magnitude than the rail head width 23. It is contemplated
that the upper insert width 22 should be slightly larger widthwise
relative to the rail head 14 as generally depicted to compensate
for slight lateral shift under load 103. Further, it will be noted
that the depth 19 of insert 21 is significantly greater in
magnitude than the depth 24 of the void site 20.
[0077] During the welding cycle, material from elements 10 and 21
are consumed such that the volumetric geometry of repair insert 21
is reduced as may be understood from a comparative inspection of
FIG. 13 versus 16. The flash material 104 and excess insert
material 106 is then removed (e.g. by grinding, machining, and/or
sheering) after the weld cycle (and optional quench cycle).
[0078] The repair insert 21 preferably further comprises an upper
head-approximating portion 26 and a lower web-approximating portion
27, however as a means to reduce the excess material as exemplified
by material(s) 104 and 106 after the weld cycle. In this regard, it
is contemplated that the upper head-approximating portion 26
preferably comprises a width 22 slightly larger than the rail head
width 24, and the lower web-approximating portion 27 comprises a
width 28 of slightly greater magnitude than the web width 29.
[0079] Notably, the maximal transverse cross-sectional insert area
as generally depicted at 112 is preferably beveled as at 42
intermediate said upper insert portion width 22 and said lower
insert portion width 28. In this regard, it is contemplated that
the beveled structures 42 approximate beveled structures 32
intermediate the rail head 14 and the rail web 13 and thereby
effectively function to minimize excess material after the weld
cycle.
[0080] After the weld and optional heat treat cycles, the rail with
welded insert site is finished by removing the flash and excess
materials 104 and 106, for example by shear die cutting the excess
from the rail 10 as generically depicted at 120. The finished,
repaired rail length 110 thus comprises a virtually seamless repair
site 125, which repair site 125 was effected by robust weld
processes per the present methodology.
[0081] Notably, the method of rail repair described hereinabove is
also useful as a method of managing the neutral rail temperature
(NRT). When the rail 10 is first installed the environmental
conditions are within a selected range. These environmental
conditions are recorded and the initial NRT is established. When a
portion of rail 10 is replaced by a new material, such as thermite
or a rail segment or plug, the NRT must then be recalculated and
tracked. By virtue of not maintaining a continuous rail during the
described method, the initial NRT is maintained.
[0082] While specific embodiments of the invention have been
described in detail, it will be appreciated by those skilled in the
art that various modifications and alternatives to those details
could be developed in light of the overall teachings of the
disclosure. For example, the method of rail repair may be said to
essentially apply to a rail 10 having upper and lower rail
sections, which upper rail may well comprise the rail head 14 and
a(n upper) portion of the rail web 13, whereas the lower rail
section may be said to comprise the rail base 11 and a (lower)
portion of the rail web 13.
[0083] Further, the method may be said to essentially comprise the
steps of initially identifying and locating a defect in a first
select rail section, which first select rail section may be
selected from the group consisting of the upper and lower rail
sections. After a defect 15 is located, a volumetric portion (as at
17) of the rail 10 may then be removed from the first select rail
section, which volumetric portion 17 includes or contains the
defect 15.
[0084] By way of removal of the volumetric portion 17, a void site
20 is exposed in the first select rail section and a pre-formed
metal insert 21 may be placed into the void site 20, thereby
effecting a rail-to-insert interface as at 101. Current 100 may
then be driven across or through the rail-to-insert interface 101
thereby heating the rail 10 and insert 21 at the rail-to-insert
interface 101 via resistance of the driven current 100, which heat
operates to effectively resistance-weld the insert 21 to the rail
10.
[0085] Notably, the continuity of a second select rail section is
maintained while exposing the void site, which second select rail
section is also selected from the group consisting of the upper and
lower rail sections, but which second select rail section is
opposite the first select rail section. Further, as noted, the void
site 20 has a maximal transverse cross-sectional site area as
generally referenced at 111 and the insert 21 has a maximal
transverse cross-sectional insert area as generally referenced at
112. Said insert area 112 is preferably greater in magnitude than
said site area 111, but approximate thereto so as to minimize the
volume of excess material that must be removed during the finishing
step(s).
[0086] The method may be said to further comprise the steps of
forcing the insert 21 against the rail 10 while driving current
across the rail-to-insert interface 101; removing oxides from the
rail-to-insert interface 101 during the step of flash welding the
insert 21 to the rail 10; and interdiffusing atomic structure of
the rail 10 and insert 21 across or through the rail-to-insert
interface 101 while forge welding the insert 21 to the rail length
10.
[0087] The foregoing methods are believed to systemically follow
from the underlying rail and repair insert combination, which
combination may be said to comprise a certain rail length 10 and a
repair insert as at 21. The rail length 10 as generally depicted
throughout the illustrations has a rail head portion 14, a rail web
portion 13, a rail base portion 11, and a void site 20 formed
therein to remove a rail defect 15. The void site 20 is located
intermediate the rail length and preferably extends into the rail
head and web portions 14 and 13. The void site 20 has a maximal
site depth as at 24 and a maximal site length as at 39.
[0088] The repair insert 21 is insertable into the void site 20 for
effecting a rail-to-insert interface as at 101. The repair insert
21 comprises an upper insert portion 26, a lower insert portion 27,
a maximal insert depth as at 19, and a maximal insert length as at
38. The insert depth 19 is greater in magnitude than the site depth
24 and the insert length 38 is greater in magnitude than the site
length 39. Both the rail length 10 and the repair insert 21 are
preferably formed from weldable materials and are thus weldable to
one another substantially as described hereinabove, although other
solid state welding techniques such as friction welding and brazing
are contemplated.
[0089] Notably, the void site 20 preferably has a wedge-shaped,
longitudinal site cross-section as generally depicted in FIGS. 4
and 6; and the repair insert 21 preferably has a wedge-shaped,
longitudinal insert cross-section as generally depicted in FIGS. 12
and 13. The wedge-shaped longitudinal site and insert
cross-sections preferably comprise substantially 90 degree angles
130 at the rail-to-insert interface 101, and respectively comprise
a beveled valley as at 40 and tip as at 41 for minimizing material
entrapment during the welding process.
[0090] From a comparative inspection of FIGS. 15(a)-15(c), it will
be seen that the upper insert portion 26 preferably comprises a
substantially uniform upper insert portion width as at 22, the
lower insert portion 27 has a substantially uniform lower insert
portion width as at 28, the rail head portion 14 has a maximum head
width as at 23, and the rail web portion 13 has a substantially
uniform web width as at 29.
[0091] The upper insert portion width 22 is preferably greater in
magnitude relative to the lower insert portion width 28 and the
head width 23. The lower insert portion width 28 is preferably
lesser in magnitude than the head width 23, but greater in
magnitude than then web width 29. The maximal transverse
cross-sectional insert area 112 is preferably beveled intermediate
said upper insert portion width 22 and said lower insert portion
width 28.
[0092] Accordingly, although the invention has been described by
reference to certain preferred and alternative embodiments and
methodologies, it is not intended that the novel disclosures and
methods herein presented be limited thereby, but that modifications
thereof are intended to be included as falling within the broad
scope and spirit of the foregoing disclosure, the following claims
and the appended drawings.
* * * * *