CN118204661A

CN118204661A - Loading and welding method for loading deck mooring track structure

Info

Publication number: CN118204661A
Application number: CN202410519120.6A
Authority: CN
Inventors: 朱雨; 钟广军; 吕忠杰
Original assignee: Jiangnan Shipyard Group Co Ltd
Current assignee: Jiangnan Shipyard Group Co Ltd
Priority date: 2024-04-28
Filing date: 2024-04-28
Publication date: 2024-06-18

Abstract

The invention provides a loading deck mooring rail structure assembly welding method, which reasonably prepares the assembly welding and connection flow of the mooring rail, firstly carries out positioning welding on the rails in the sections in a reverse state, then carries out welding on the mooring rail and the deck, and finally carries out back sealing welding and welding on the rails between the sections in a normal mode. The assembly and welding method is reasonable in overall flow, proper in assembly method and sequence, easy to operate and convenient to master, meets the technical requirements and the precision requirements of the assembly and welding of the mooring track real ship, withstands the test of the use of the real ship, and achieves the function of deck loading diversification. The invention also provides a welding process and welding parameters of a reliable experiment, each link in the process effectively controls the installation precision requirement of the structure, and lays a safe and reliable platform for loading the deck of the real ship, thereby being widely applied to the welding of the real ship of the similar structure of the related ship.

Description

Loading and welding method for loading deck mooring track structure

Technical Field

The invention relates to the technical field of ship construction, in particular to a loading and welding method of a loading deck mooring track structure.

Background

The loading deck mooring rail is a special whole extruded aluminum alloy hollow box-shaped special mooring device, and as shown in fig. 1 and 2, the mooring rail comprises an upper panel, a lower bottom plate and a longitudinal web, and a bushing hole 30 is formed in the upper panel and used for traction and fixation of mooring equipment. The ship loading device is longitudinally arranged on the loading deck along the ship length direction and is used for increasing the number of tie-in points and loading capacity of ships on carrying equipment, and the deck loading diversity function can be realized.

The structure is applied to a real ship for the first time, and can replace the original deck mooring hole structure after application. The structure is constructed by planning the installation stage, sectional installation and effective airtight butt joint, belongs to a heavy-duty structure, and ensures welding quality, which are the installation elements to be fully considered.

The structure needs to bear higher mooring weight, and extremely high requirements are put on manufacturing and installation of the whole ship in order to ensure the safety of the whole ship. In order to meet the design technical requirements and the assembly welding requirements, the invention tries to provide a practical assembly welding technology of a real ship suitable for loading a deck mooring track structure, which firstly ensures that the structure is reliable in quality and strength, meets the precision requirements, further ensures reasonable assembly welding of the real ship, and further can ensure loading mooring operation.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a practical real ship welding method suitable for loading a deck mooring rail, which mainly comprises the following steps: the method comprises the steps of scribing on the jig frame, scribing on the deck, scribing structural parts, mooring the rail on the jig frame, positioning welding of the rails, butt welding between the rails, welding the rails and the deck and the like.

To achieve the above and other related objects, the present invention provides a method of welding a loading deck mooring rail structure, comprising the steps of:

S1: scribing on the jig frame; marking a deck splicing seam position line, a mooring track center line and a seam line between the mooring track center line and a loading deck on a jig according to the requirements of a sectional construction process;

s2: hanging the deck to the jig frame; reserving the installation position of the mooring rail on the jig frame, automatically welding jointed boards on the deck and the outer plate part, locally leveling, and then hoisting the deck on the jig frame;

S3: scribing the structural member; manually scribing the deck according to the sectional structure diagram, wherein the manual scribing comprises longitudinal bones, cross beams, position lines of bulkheads and allowance lines of the deck at the joint of the deck and the rail;

S4: hanging the tethered rail to the jig frame; hoisting the upper jig frame in a reverse state by each mooring rail so that the lower bottom plate of the mooring rail is positioned above the upper jig frame; the mooring track comprises an upper panel, a lower bottom plate and two parallel longitudinal webs, so that a rectangular inner cavity is formed, a bushing hole is formed in the upper panel, the width of the upper panel along the ship width direction is larger than that of the lower bottom plate, and the edges of the two sides of the upper panel are outwards protruded out of the vertical surface where the longitudinal webs are located along the ship width direction.

Preferably, the welding method further comprises the following steps:

s5: positioning welding of mooring rails and butt welding of segmented inner rails;

(1) Mooring track tack welding

Cutting the deck allowance at the joint of the mooring rail according to the mooring rail measurement data, and performing positioning welding; the upper panel of the mooring rail is welded and fixed with the jig frame through two longitudinal templates, the upper panel of the mooring rail and the mooring rail are positioned on the same horizontal plane, the two longitudinal templates are respectively and correspondingly positioned below the two longitudinal webs, and the longitudinal templates and the longitudinal webs are positioned on the same vertical plane; the transverse templates are positioned between the loading deck and the jig frame and used for auxiliary support of the loading deck;

the temporary reinforcing and fixing are carried out on the horse plates made of dense aluminum alloy before the welding in the ship width direction, and the horse plates are positioned below the joints of the mooring rail and the loading deck so as to carry out auxiliary support on the mooring rail and the loading deck, and deformation or position deviation is avoided.

Preferably, step S5 further comprises:

(2) Butt welding between segmented inner rails

A through welding hole is formed in the end part of the longitudinal web plate of the mooring rail, so that welding seams can continuously pass when two mooring rails are in butt joint; the end parts of the upper panels of the two mooring rails are welded continuously in double-sided and multi-channel mode, grooves are formed in the surfaces, facing the inner cavity, of the end parts of the upper panels of the two mooring rails, the surfaces, facing the inner cavity, of the butt joint parts of the upper panels of the two mooring rails are welded, and after the upper panels are turned over in the subsequent step, the surfaces, far away from the inner cavity, are welded for back cover welding;

And forming process holes at the end parts of the lower bottom plates of the two mooring rails, attaching ceramic gaskets to the surfaces of the longitudinal webs facing the inner cavity at the butt joint positions through the process holes, forming grooves on the surfaces of the end parts of the longitudinal webs far away from the inner cavity, performing single-sided welding and double-sided forming welding, and polishing butt welding seams on the surfaces of the longitudinal webs facing the inner cavity.

Preferably, the welding method further comprises the following steps:

S6: the mooring rail is welded with the deck; after the marking of the loading deck is finished and Application for Inspection is qualified, before the structural components are assembled, adopting a MIG semi-automatic welding method to start butt welding of the mooring rail and the loading deck, welding the surface of the seam part of the upper panel of the mooring rail and the loading deck along the ship length direction, facing the inner cavity, and locally weighting the upper surface position of the mooring rail during welding.

Preferably, the welding method further comprises the following steps:

S7: assembling the sectional members; sequentially installing structural members including a sectional inner bulkhead, T-shaped materials and toggle plates, wherein in the assembly positioning, TIG welding is adopted for butt welding; MIG welding is adopted for the corner joint welding; the welding is performed according to the following sequence:

after the sectional assembly is finished, before the sectional welding is started, the welding of the mooring rail and the cross beam and the cabin wall plate is finished;

firstly welding butt joint and rear corner joint, and firstly standing and then flat welding;

And the bottom plate and the side plate of the circular transition section of the mooring track are continuously welded on one side, so that the tightness of welding seams is ensured.

Preferably, the welding method further comprises the following steps:

s8: sealing and repairing the process hole; and (3) adopting a sealing plate gland at the process hole of the lower bottom plate, wherein the sealing plate is positioned on the surface of the lower bottom plate far away from the cavity and is larger than the size of the process hole, and strictly and carefully checking the assembly gap between the open hole and the sealing plate in the process, so that the assembly gap is controlled to be 0-1.0 mm.

Preferably, the welding method further comprises the following steps:

S9: sealing the bottom of the mooring rail and the deck; turning over the ship body section, enabling the upper panel of the mooring rail to face upwards, and performing bottom sealing welding on the surface, far away from the cavity, of the butt welding seam of the upper panel of the mooring rail and the deck; and simultaneously, welding the unfinished bottom sealing welding in the section in the step S5, and performing the bottom sealing welding on the surface, far away from the inner cavity, of the butt joint part of the mooring rail in the section.

Preferably, step S9 further includes: butt welding the tie down rail at the joint of the two segments, comprising:

A through welding hole is formed in the edge of the longitudinal web plate of the mooring rail, which is positioned at the end part of the section, so that a welding line continuously passes through; the sectional joint of the upper panel of the mooring rail adopts double-sided multi-pass continuous welding, the surface of the sectional joint of the upper panel facing the inner cavity is firstly subjected to overhead welding, and then the surface of the sectional joint of the upper panel far away from the inner cavity is subjected to flat welding; the surface of the segmented joint facing the inner cavity is provided with a small groove, and the surface of the segmented joint far away from the inner cavity is provided with a large groove;

the sectional joints of the two mooring rail bottom plates are provided with process holes, ceramic gaskets are attached to the surfaces of the longitudinal webs facing the inner cavity through the process holes, grooves are formed in the surfaces, far away from the inner cavity, of the end parts of the longitudinal webs, single-sided welding and double-sided forming welding are carried out, and then butt welding seams of the surfaces, facing the inner cavity, of the longitudinal webs are polished.

The invention provides a loading deck mooring rail structure assembling and welding method, which reasonably prepares the assembling and welding and connecting processes of the mooring rail, firstly, the positioning welding of the rails in the sections is carried out in a reverse state, then the mooring rail is welded with the deck, and finally, the welding of the bottom sealing welding and the welding of the rails between the sections are carried out in a normal mode by turning over. The assembly and welding method is reasonable in overall flow, proper in assembly method and sequence, easy to operate and convenient to master, meets the technical requirements and the precision requirements of the assembly and welding of the mooring track real ship, withstands the test of the use of the real ship, and achieves the function of deck loading diversification. The invention also provides a welding process and welding parameters of a reliable experiment, each link in the process effectively controls the installation precision requirement of the structure, and lays a safe and reliable platform for loading the deck of the real ship, thereby being widely applied to the welding of the real ship of the similar structure of the related ship.

Drawings

Fig. 1 shows a schematic cross-sectional structure of a tie down rail.

Fig. 2 shows a schematic perspective view of the mooring track.

FIG. 3 is a block diagram of the process flow of the soldering method of the present invention.

Fig. 4 shows a block diagram of the tethered track crane to a jig frame of the present invention.

Fig. 5 shows a schematic view of the placement of the horse board of the present invention.

Fig. 6 shows a cross-sectional view of the invention at the track interface in segments.

Fig. 7 is a cross-sectional view of the position a of fig. 6 along the vertical plane of the track along the length direction.

Fig. 8 is a cross-sectional view of the B position of fig. 6 along the vertical plane of the track length.

Fig. 9 is a cross-sectional view of the C position of fig. 6 along the horizontal plane of the track length.

Fig. 10 shows a cross-sectional view of the invention where two segments meet.

Fig. 11 is a cross-sectional view of fig. 10 taken along the vertical plane of the rail at position E.

Fig. 12 shows an enlarged view of position F in fig. 10.

Description of element reference numerals

2. A loading deck; 3. mooring the track; 4. a transverse template; 5. a longitudinal template; 9. a horse board; 10. a ceramic liner; 21. a process hole; 11. a sealing plate; 30. a liner hole; 31. an upper panel; 32. a lower base plate; 33. a longitudinal web;

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.

As described in detail in the embodiments of the present invention, the cross-sectional view of the device structure is not partially enlarged to a general scale for convenience of explanation, and the schematic drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.

For ease of description, spatially relative terms such as "under", "below", "beneath", "above", "upper" and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Furthermore, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers or one or more intervening layers may also be present. As used herein, "between … …" is meant to include both endpoints.

In the context of the present application, a structure described as a first feature being "on" a second feature may include embodiments where the first and second features are formed in direct contact, as well as embodiments where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of each component in actual implementation may be changed at will, and the layout of the components may be more complex.

As shown in fig. 3, the invention provides a loading deck mooring rail structure assembly and welding method, which comprises the following steps:

s1: scribing on the jig frame. And (3) marking a deck splicing seam position line, a mooring track center line, a seam line between the mooring track center line and a loading deck and the like on the jig frame according to the requirements of a sectional construction process.

S2: the deck is suspended to the jig frame. And reserving the installation position of the mooring rail on the jig frame, automatically welding jointed boards on the deck and the outer plate part, locally leveling, and then hoisting the deck on the jig frame.

S3: and (5) scribing the structural part.

And (3) manually scribing on the deck according to the sectional structure diagram, wherein the scribing comprises longitudinal bones, cross beams, position lines of bulkheads, allowance lines of the deck at the joint with the rail, and the like. And a certain welding shrinkage compensation amount is added along the ship length and the ship width during scribing.

And taking the center line of the middle section as a reference position, respectively adding a certain amount of reverse deformation to the two ends along the ship length direction, and carrying out local correction after the sectional welding is finished.

Arc transition sections are arranged on the bow section and the stern section decks, and the mooring rails are bent and welded by plates so as to ensure the surface fit with the bow section and the stern section decks. When the sectional jig frame is manufactured, a certain amount of reverse deformation is added along the profile depth at the bow and stern sealing plates of the arc transition section.

S4: the tethered rails are suspended to the jig frame.

Hoisting the upper jig frames one by one in a reverse state by the mooring rails 3, so that the lower bottom plate 32 of the mooring rails is positioned above; the mooring rail 3 comprises an upper panel 31, a lower bottom plate 32 and two parallel longitudinal webs 33, so as to enclose a rectangular inner cavity, the upper panel 31 is provided with a bushing hole, the width of the upper panel 31 along the width direction of the ship is larger than that of the lower bottom plate 32, namely, the two side edges of the upper panel 31 are outwards protruded from the vertical surface where the longitudinal webs 33 are located along the width direction of the ship.

Splayed binding belts are adopted during lifting, and are firmly bound at two ends of each track.

The device is slowly moved during hoisting, so that collision and friction between the mooring rail and equipment, personnel and other sundries in a workshop are prevented.

S5: and (5) positioning welding of the tethered rails and butt welding of the segmented inner rails.

(1) Mooring track tack welding

Cutting the deck allowance at the joint of the mooring rail according to the mooring rail measurement data, and performing positioning welding; as shown in fig. 4, the upper panel of the mooring rail 3 is welded and fixed with the jig frame through two longitudinal templates 5 (adopting low-current welding to control the height of the welding leg), the upper panel of the mooring rail 3 and the mooring rail 3 are positioned on the same horizontal plane, the two longitudinal templates 5 are respectively and correspondingly positioned below the two longitudinal webs, and the longitudinal templates 5 and the longitudinal webs are positioned on the same vertical plane. As shown in fig. 3. A transverse formwork 4 is located between the loading deck and the moulding bed for auxiliary support of the loading deck 2.

The horse plate 9 made of dense aluminum alloy is needed to be temporarily reinforced and fixed before welding in the ship width direction (the blank position of the angle steel of the non-jig frame, the position avoiding the track maintenance hole and the hole opening of the bushing), as shown in fig. 5. The horse plate 9 is positioned below the joint of the mooring rail 3 and the loading deck 2 to assist in supporting the two from deformation or positional displacement.

(2) Butt welding between segmented inner rails

A through welding hole is formed in the end part of the longitudinal web plate 33 of the mooring rail, so that welding seams can continuously pass when two mooring rails are in butt joint;

The end parts (butt joint parts) of the upper panels 31 of the two mooring rails are subjected to double-sided multi-channel continuous welding, wherein, as shown in fig. 6 to 9, the surfaces of the end parts of the upper panels 31 facing the inner cavity are provided with grooves, the surfaces of the butt joint parts of the upper panels of the two mooring rails facing the inner cavity are firstly welded, and after the step S9 turns over, the surfaces far away from the inner cavity are welded and subjected to bottom sealing welding; here the surface facing the lumen is the inner side and the surface facing away from the lumen is the outer side.

The ends of the lower bottom plates 32 of the two mooring rails are provided with process holes 21, ceramic gaskets 10 are attached to the surfaces of the longitudinal webs 33 of the butt joint parts facing the inner cavity through the process holes 21, grooves are formed in the surfaces of the ends of the longitudinal webs 33, which are far away from the inner cavity, single-sided welding and double-sided forming welding are carried out, and butt welding seams of the surfaces of the longitudinal webs facing the inner cavity are polished.

The relevant welding parameters are shown in table 1 below.

TABLE 1 recommended parameters for segment inner track butt welding

S6: the mooring rail is welded to the deck.

After the marking of the loading deck is finished and Application for Inspection is qualified, the butt welding of the mooring rail and the loading deck is started by adopting a MIG semi-automatic welding method before the structural members are assembled, the surface of the joint of the upper panel of the mooring rail and the loading deck along the ship length direction, which faces the inner cavity, is welded, and the upper surface of the mooring rail can be locally weighted at a proper position during welding.

As the single welding line is longer along the ship length direction, a split-medium step-by-step welding withdrawal method is adopted. Preferably, symmetrical welding (in the sections) is used, deformation conditions of the rail are observed at any time in the welding process, and the deformation conditions are corrected in time (flattened by adopting a mechanical method).

S7: the segmented components are assembled.

And structural members such as a sectional inner bulkhead, a T-shaped section, a toggle plate and the like are sequentially installed, and the installation angle of the parts is noted.

In the assembly positioning, TIG welding is preferably adopted for butt welding; the fillet weld is preferably MIG weld.

The corner of the mooring rail is provided with a hole on the wall plate to enable the mooring rail to pass through, and a longitudinal web plate is grooved (edge polishing smooth) to keep the bottom plate of the inner cavity of the mooring rail smooth and unblocked.

The mooring rail is used for independently blanking, processing and welding the bow and stern rotary circular sections of the ship body by using an aluminum plate.

The welding is preferably performed according to the following sequence:

a) After the sectional assembly is finished, welding the mooring rail and the cross beam and the cabin wall plate is finished before the sectional assembly is welded;

b) Firstly welding butt joint and rear corner joint, and firstly standing and then flat welding;

c) And the bottom plate and the side plates of the circular transition section of the mooring track are continuously welded on one side (the welding feet are increased by about 10 percent, and the minimum value is 1 mm), so that the tightness of welding seams is ensured.

The welding deformation correction requirements are as follows:

a) According to the requirements of CB 20111, mechanical or pyrogenic correction is adopted for deformation correction;

b) Correcting the deformation of the mooring orbit and the bone material, and correcting the deformation of the wallboard;

c) Preferably symmetrically to the mid-axis of the mid-line and cross-section of the hull; in the height direction, the process should be performed from bottom to top.

S8: and (5) sealing and repairing the process hole.

The process hole of the lower bottom plate is capped by a sealing plate 11, referring to fig. 6, the sealing plate 11 is positioned on the surface of the lower bottom plate far away from the cavity and is larger than the size of the process hole 21, and the assembly gap (controlled between 0 and 1.0 mm) between the open hole and the sealing plate is required to be carefully checked in the process.

The edge of the opening hole is smooth, burr-free and greasy. And (3) carrying out seal plate lap welding by using TIG welding, controlling the height of welding legs by using small current, and ensuring watertight.

In fig. 6, a complete cross-sectional view of the welded sealing plate is shown, in which the welding in step S5 is performed first, and then the sealing plate in step S8 is welded.

S9: mooring rail and deck bottom sealing weld

After turning over the hull section, as shown in fig. 10, the upper panel 31 of the mooring rail is turned up, the upper panel 31 of the mooring rail and the surface of the deck butt weld, which is far away from the cavity, are subjected to bottom sealing welding, as shown in fig. 12, the inside groove welding is completed in step S6, and after turning over in step S9, the bottom sealing welding is performed. Meanwhile, the unfinished bottom sealing welding in the section in the step S5 is welded, namely, the outside in fig. 7 is welded in a bottom sealing manner, specifically, the surface (the surface is positioned at the uppermost layer after turning over) of the butt joint of the mooring rail in the section, which is far away from the inner cavity, is welded in a bottom sealing manner.

The MIG pulse argon arc welder is adopted for welding, so that the appearance quality of the welding line is ensured, and the defects of air holes, cracks, arc pits and the like are avoided. The single welding seam is preferably treated by a split step-by-step welding method. Preferably, symmetrical welding (in the segments) is used in the length direction.

In the step, butt welding is also needed to be carried out on the mooring rails at the joints of the two sections after turning.

A weld hole is opened at the edge of the tie down rail longitudinal web 33 at the end of the segment to allow the weld to pass continuously.

Similar to step S5, the sectional seam of the tie-down track upper panel 31 is welded continuously in multiple passes on both sides, as shown in fig. 11, the upper panel is welded first by overhead welding and then by flat welding, that is, the surface of the sectional seam of the upper panel 31 facing the inner cavity is welded first by overhead welding, and then the surface of the sectional seam of the upper panel 31 facing away from the inner cavity is welded flat. The surface of the segmented joint facing the inner cavity is provided with a small bevel, and the surface far away from the inner cavity is provided with a large bevel, namely the bevel far away from the inner cavity surface is larger than the bevel facing the inner cavity surface.

The sectional joints of the two mooring rail bottom plates are provided with process holes 21, ceramic liners 10 are attached to the surfaces of the longitudinal webs 33 of the butt joint parts, facing the inner cavity, of the process holes 21, grooves are formed in the surfaces, far away from the inner cavity, of the end parts of the longitudinal webs, single-sided welding and double-sided forming welding are carried out, and then butt welding of the surfaces, facing the inner cavity, of the longitudinal webs is polished.

The welding parameters for butt welding the tie down rails at the two segment joints are shown in table two below.

And (II) table: recommended parameters for butt welding of track at segmented joint

In summary, the invention provides a loading deck mooring rail structure assembling and welding method, which reasonably prepares the assembling and welding and connecting processes of the mooring rail, firstly, the positioning welding is carried out on the rails in the sections in a reverse state, then the mooring rail is welded with the deck, and finally, the welding is carried out on the mooring rail and the deck in a reverse state, and finally, the welding of the bottom sealing welding and the welding of the rails between the sections are carried out in a normal mode. The assembly and welding method is reasonable in overall flow, proper in assembly method and sequence, easy to operate and convenient to master, meets the technical requirements and the precision requirements of the assembly and welding of the mooring track real ship, withstands the test of the use of the real ship, and achieves the function of deck loading diversification. The invention also provides a welding process and welding parameters of a reliable experiment, each link in the process effectively controls the installation precision requirement of the structure, and lays a safe and reliable platform for loading the deck of the real ship, thereby being widely applied to the welding of the real ship of the similar structure of the related ship.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims

1. A method of welding a loading deck tethered rail structure, the method comprising the steps of:

2. The method of assembling and welding as recited in claim 1, further comprising the steps of:

(1) Mooring track tack welding

Cutting the deck allowance at the joint of the mooring rail according to the mooring rail measurement data, and performing positioning welding; the upper panel of the mooring rail is welded and fixed with the jig frame through two longitudinal templates, the upper panel of the mooring rail and the mooring rail are positioned on the same horizontal plane, the two longitudinal templates are respectively and correspondingly positioned below the two longitudinal webs, and the longitudinal templates and the longitudinal webs are positioned on the same vertical plane;

the transverse templates are positioned between the loading deck and the jig frame and used for auxiliary support of the loading deck;

3. The method of assembling and welding as recited in claim 2, wherein step S5 further includes:

(2) Butt welding between segmented inner rails

4. A method of assembling and welding as claimed in claim 3, further comprising the steps of:

5. The method of assembling and welding as recited in claim 4, further comprising the steps of:

6. The method of assembling and welding as recited in claim 5, further comprising the steps of:

7. The method of assembling and welding as recited in claim 6, further comprising the steps of:

8. The method of assembling and welding according to claim 7, wherein step S9 further comprises: butt welding the tie down rail at the joint of the two segments, comprising: