JPH115162A - Structure coated with titanium clad steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure in which a projecting structure is connected to a structure coated with a titanium clad steel sheet for surface corrosion resistance without impairing corrosion resistance. SOLUTION: An area where the titanium clad steel sheet is cut off is provided in a part of an area covered with a titanium clad steel sheet 2,
A stainless steel projection structure 3 is arranged so as to be connected to the steel structure 1 in the cut area, the steel structure and the stainless steel projection structure are welded to each other, and the cut titanium clad steel sheet is further cut. The notch 8 formed by the three members of the steel base material, the steel structure and the stainless steel projection structure of the titanium clad steel plate at the cut end face of the steel is so formed as not to contact the titanium clad material of the titanium clad steel plate. Fill welding 6 and further cover the overlay weld including the dissimilar joint between the titanium cladding material of the titanium clad steel sheet and the steel base material and the weld boundary between the stainless steel projection structure and the overlay weld. A titanium clad steel sheet coated structure characterized by being subjected to silver brazing 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel structure covered with a titanium clad steel plate, and more particularly to a structure in which a splash zone of a pillar in an offshore structure is covered with a titanium clad steel plate. .

[0002]

2. Description of the Related Art Titanium is used in chemical plants and aircraft parts because of its excellent corrosion resistance, and its use is expanding. However, its high price is a practical constraint. As a means for solving this, a titanium clad steel sheet having a base material of steel and a titanium surface has recently been used for surface corrosion resistance, and a pillar in an offshore structure is one example.

Taking steel pillars in an offshore structure as an example, the marine part and the underwater part of the pillars are each subjected to corrosion resistance treatment, but are exposed to the atmosphere while being wet with sea water called a splash zone. The parts cannot be sufficiently prevented from corroding by ordinary corrosion treatment. Therefore, a means for preventing corrosion by covering with a titanium clad steel plate so as to surround four circumferences of the pillar in the splash zone of the pillar is taken.

[0004] The titanium clad material of the titanium clad steel sheet is usually thin because titanium is an expensive metal. Therefore, when the ship comes in direct contact with the titanium clad steel sheet on the surface of the marine structure, the titanium cladding material is easily damaged, and seawater enters from that portion, and the corrosion of the internal steel structure proceeds. . To prevent this,
It is effective to install fenders around offshore structures. In order to fix the fender around the offshore structure, it is common to install a fender fixing projection on the offshore structure.

[0005] Even if the surface is covered with a titanium clad material of titanium clad steel sheet, corrosion progresses from the inside of the steel sheet when seawater enters into the welded portion at the end face of the titanium clad steel sheet, etc. Care must be taken in the welding of, for example, a welding structure as disclosed in JP-A-5-185237 is required. Therefore, the structure of the region of the splash zone covered with the titanium clad steel sheet is simplified, and a protruding structure that is likely to cause seawater to enter the titanium clad steel sheet is not provided. Attempting to cover the joint between the protruding structure and the titanium-clad steel plate by welding results in dissimilar joining of titanium and iron, and a large amount of iron dissolves into the weld metal, causing intermetallic compounds of iron and titanium, TiC or TiN.
It can be said that welding is impossible because a large amount of such a compound is produced, which makes the weld metal brittle.

Therefore, conventionally, a projecting structure is welded to the sea surface above the splash zone which is not covered with a titanium clad steel plate, and an extension is further connected from the projecting structure, and a fender is attached to the tip of the extension. Was fixed.

[0007]

As described above, no projection structure is provided on the portion covered with the titanium clad steel sheet,
In the method of laying a fender with a projection structure provided on a portion not covered with a titanium clad steel sheet and further providing an extension, the external force acting on the fender is increased as a large moment due to the presence of the extension. To act on the structure,
The offshore structure and the protruding structure had to be designed to be strong and large. The present invention provides a protruding structure at a site covered with a titanium clad steel sheet, further does not expose a corrosive steel portion in the vicinity of the protruding structure, does not enter seawater, and has no fragile layer. An object of the present invention is to provide a marine structure having a structure, thereby solving the above-mentioned problems.

[0008]

The gist of the present invention is as follows: (1) In a steel structure in which all or a part of the surface is coated with a titanium-clad steel plate, one part of a region covered with the titanium-clad steel plate is provided. A portion where the titanium clad steel plate is cut off is provided in the portion, and a stainless steel protrusion structure is arranged so as to be connected to the steel structure in the cut region, and the steel structure and the stainless steel protrusion structure are provided. The notch formed by the three members of the titanium clad steel sheet steel base material, the steel structure and the stainless steel projection structure at the cut end face of the titanium clad steel sheet which is further cut off by welding The weld is welded so that it does not come into contact with the titanium cladding material, and the dissimilar joint between the titanium cladding material and the steel base material of the titanium clad steel sheet and the projection structure made of stainless steel and A titanium clad steel sheet-coated structure characterized by being brazed with silver so as to cover the overlay welding portion including a joining boundary with a contact portion.

(2) In a steel structure in which all or a part of the surface is coated with a titanium-clad steel plate, a base plate is welded and connected to a part of the surface of the steel structure. Coating the surface,
An area where the titanium clad steel sheet is cut off is provided on a part of the surface of the base plate, and a cutout hole that penetrates the base plate is provided in an area smaller than the cutout area in the cutout area. A stainless steel projection structure is arranged to fit, the base plate and the stainless steel projection structure are welded and joined, and a steel base material of a titanium clad steel plate at a cut end face of the titanium clad steel plate further cut off, The notch formed by the base plate and the projection structure made of stainless steel is welded so as not to come into contact with the titanium cladding material of the titanium clad steel plate. Including the joining boundary between the dissimilar joint portion and the stainless steel projection structure and the overlay welding portion. Titanium clad steel plate coating structure characterized by comprising to put silver brazing so as to cover the overlay weld.

(3) In a steel structure in which all or a part of the surface is coated with a titanium-clad steel plate, a base plate is welded and connected to a part of the surface of the steel structure. Coating the surface,
An area where the titanium clad steel sheet is cut off is provided on a part of the surface of the base plate, and a stainless steel projection structure is arranged so as to be connected to the base plate in the cut area, and the base plate and the stainless steel projection structure are arranged. The notch formed by the three members of the titanium clad steel plate base material, the base plate, and the stainless steel projection structure at the cut end face of the titanium clad steel plate that has been cut off is welded to the titanium clad steel plate. Overlay welding so as not to contact the joining material, further including the joining boundary between the different joining portion of the titanium joining material of the titanium clad steel sheet and the steel base material and the stainless steel projection structure and the overlay welding portion. A titanium clad steel sheet coated structure characterized by being brazed with silver so as to cover a weld overlay.

(4) The structure coated with titanium clad steel sheet according to (1) to (3), wherein a petrolatum paste (JIS Z1903) is applied instead of silver brazing.

(5) The titanium clad steel sheet-coated structure according to (4), wherein the petrolatum paste-coated portion is covered with another structure connected via a stainless steel projection structure.

(6) A shoulder is provided near the end of the stainless steel projection structure on the connection side with the steel structure, and the plane of the shoulder is on the same plane as the surface of the titanium clad steel sheet. The structure coated with titanium clad steel sheet according to any one of (1) to (5), characterized in that:

(7) The stainless steel projection structure constitutes a male screw, and another structure is fixed by connecting a stainless steel nut to the male screw portion, and titanium for covering the stainless steel nut. The titanium-clad steel sheet-coated structure according to any one of (1) to (6), wherein a cap made of steel is disposed, and the inside of the cap is filled with an anticorrosive agent. It is.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Titanium can be welded to a metal similar to titanium, but welding of different metals such as titanium and steel makes the weld metal embrittled as described above. It cannot be used for coating the surface of structures. Therefore, for a structure used in a corrosive atmosphere, a titanium clad steel plate is used for the surface coating. The titanium composite material used for the titanium clad steel sheet may be any one type to three types specified in JIS. The base material of the titanium clad steel sheet is steel, and when the surface of the steel structure is covered with the titanium clad steel sheet, the structure can be welded to the base material of the titanium clad steel sheet. Thereby, welding between dissimilar metals can be avoided. The weld between the structure and the titanium clad steel base metal and the weld between the titanium clad steel base metal must be coated with titanium to prevent corrosion, so that the weld metal is not embrittled and seawater intrusion is prevented. Is described in, for example,
No. 237 is adopted.

[0016] A structure (hereinafter referred to as a "projection structure") provided on a steel structure in a projecting manner is exposed to such a severe environment that a titanium coating is required for corrosion protection on the steel surface, so that the steel is exposed on the surface. It is not possible to adopt a structure that does. Further, since a fender is installed on the projection, even if the projection is coated with a titanium-clad steel sheet, the titanium coating is easily worn away and long-term corrosion resistance cannot be maintained. Further, the projections need to be firmly joined to the steel structure by welding connection, and the use of titanium or a titanium alloy cannot be used because different types of joining are required. Due to such restrictions, the projections were made of stainless steel. Thereby, corrosion resistance and a strong connection with the structure were made possible. SUS304, SUS as stainless steel
316L or the like can be used.

The surface of the steel structure to which the stainless steel projection structure is to be connected is cut off from a titanium clad steel plate covering only the surface. Titanium clad steel sheet may be cut into its shape in advance and used,
When a plurality of titanium-clad steel plates are combined to cover the surface, it is also possible to cope by not disposing the titanium-clad steel plate only at a portion where the stainless steel projection structure is to be connected.

In the first embodiment of the present invention shown in FIG. 1, the stainless steel projecting structure 3 is directly welded to the steel structure 1 at a weld 5. The cut portion of the titanium clad steel plate is slightly larger than the cross section of the stainless steel protrusion structure, and cut between the cut end surface of the cut titanium clad steel, the steel structure and the stainless steel protrusion structure. A notch 8 is formed. A welded portion 6 is formed so as to fill the notch. The welded portion 6 is joined only to the base material 21 of the titanium clad steel plate at the cut end face of the titanium clad steel plate, but not to the titanium clad material 22. This is to prevent the weld metal from being embrittled by preventing welding between different metals of titanium and iron. Due to the formation of the welded portion 6, the titanium clad steel plate and the steel structure are joined at the cut end surface of the titanium clad steel plate. The welding portions 5 and 6 can be formed using a welding method such as a covered arc welding method or a TIG welding method using stainless steel welding materials D316L and Y316L.

The weld 6 is made of stainless steel diluted with mild steel, and its surface has no corrosion resistance. Therefore, a coating having corrosion resistance equivalent to that of titanium or stainless steel is required. In this embodiment, a coating 7 by silver brazing is used. In the silver brazing, Ag or Ag-Cu-Zn-Sn-Cd-based brazing is used as a melting material, and the coating is performed by a torch brazing or a resistance brazing method. Since silver brazing is performed at a melting temperature of 1100 ° C. or less, the material to be welded does not melt. Therefore, although the dissimilar metals of titanium and iron are in contact with each other, the problem of embrittlement of the weld does not occur. Also, since this silver brazed part is intended to cover the surface and does not bear any structural strength,
Sufficient bonding strength can be ensured in brazing.

In the second embodiment of the present invention shown in FIG. 2, a base plate 4 is used for connecting the projection structure 3 made of stainless steel. If the steel structure 1 is, for example, a pier of an offshore structure, the thickness of the steel structure 1 is selected to secure the strength as a pier, but it is sufficient to support the moment generated by the external force applied to the stainless steel projection structure. May not have sufficient strength. In such a case, a base plate 4 having a thickness sufficient to support the moment is arranged, and the stainless steel projecting structure 3 is welded to the base plate, and a gap between the base plate 4 and the steel structure is provided at an end of the base plate. By joining with the provided welded portion 11, the local moment applied to the steel structure can be reduced.

In this case, a stainless steel projection structure may be placed on a flat base plate and the corners may be connected by fillet welding, or a through hole may be formed in the base plate as shown in FIG. A stainless steel projection structure may be penetrated into the hole, and the two may be connected by welding. In the latter, by providing a groove 9 in the base plate,
Since a bead pile like the welded portion 5 in FIG. 1 is not formed in the notch portion 8, the effect that the formation of the welded portion 6 and the silver brazed portion 7 is not adversely affected is provided. Also,
By forming the welded portion 10, the joining strength between the base plate and the stainless steel projection structure can be further improved.

The installation of the base plate causes a step on the steel structure. The titanium clad steel sheet needs a structure that covers both the steel structure and the base plate and prevents seawater from entering. As shown in FIG. 2, a titanium plate 12 is bridged between titanium clad steel plates
The required titanium coating can be realized by joining the titanium cladding material 22 and the titanium clad steel plate 22 by the TIG welding method.

The coating of the welded portion 6 can be performed by applying a petrolatum paste (JIS Z1903) instead of silver brazing. Petrolatum paste is a paste-like substance containing petrolatum, which is a kind of petroleum wax separated from crude oil by vacuum distillation, as a main component and added with a corrosion inhibitor and the like. Exhibits anticorrosion function by suppressing permeation of water. The application can be performed by a method in which an operator manually applies an appropriate amount to the application portion. In connecting a structure such as a fender, if the structure is arranged so as to cover the petrolatum paste application portion, the durability of the petrolatum paste portion can be improved.

When a stainless steel structure is formed in a bolt shape and a hard rubber fender is connected thereto via a stainless steel nut, corrosion of the stainless steel nut may progress. In order to prevent such corrosion of the nut, it is effective to cover the nut portion with a titanium cap and fill the inside with a corrosion inhibitor such as petrolatum paste.

The shape of the stainless steel projection structure is shown in FIG.
1 and 2, a shoulder is provided near the end on the connection side with the steel structure as shown in FIGS. 1 and 2, and the plane of the shoulder is the same as the surface of the titanium clad steel sheet. May be configured to be on a plane. By providing the flat surface of the shoulder, the weld metal is built up along the projection of the stainless steel projection structure, the workability of the work of brazing thereon is improved, and the reliable construction is facilitated.

[0026]

【Example】

(Example 1) A pillar of an offshore structure is formed in the shape of a quadrangular prism using a 12 mm-thick steel plate for general structural use, and four rounds of a portion corresponding to a splash zone of the pillar are covered with a titanium clad steel plate. did. In the titanium clad steel sheet 2, the thickness of the titanium composite material 22 was 1.0 mm, and the total thickness including the base material 21 was 5 mm. A stainless steel bolt-like projection 3 for attaching a fender was connected to a part of the coating portion of the titanium clad steel plate. The cross section of the connecting portion is as shown in FIG. SUS31 as stainless steel material
6 L was used. The protrusion had a length of 120 mm, a base width of 60 mm, and a bolt portion diameter of 40 mm. A shoulder was provided on the projection, and the surface of the titanium clad steel sheet and the plane of the shoulder constituted the same plane. A 25 mm-thick general structural steel material was used as a base plate, a through hole was formed in the base plate, and a groove was provided on the upper and lower surfaces, and a stainless steel bolt-like projection was fitted and connected. For the connection, a Phillips arc stud welding method for generating an arc between the stud and the base material was adopted, and the four circumferences of the base plate connected to the stainless steel projection structure were welded to the steel structure as welds.

Surface of steel structure 1 and base plate 4
Was joined to a titanium clad steel sheet 2. At the step between the titanium clad steel plate on the steel structure and the titanium clad steel plate on the base plate, the titanium thin plate 12 is cross-linked, and the titanium thin plate and the titanium clad material of the titanium clad steel plate are welded by TIG welding without using a welding material. Welding and joining achieve a sealed structure.

The end surface of the cut portion of the titanium clad steel plate on the base plate has a width of 7 mm between the cut surface and the stainless steel projection structure.
It was arranged so that the notch part 8 of mm may be comprised. The notch was overlaid 6 by TIG welding using stainless steel welding material Y316L as a melting material. The build-up height was 4 mm so that dissimilar material welding between the titanium clad material of the titanium clad steel sheet and the base material did not occur. Silver brazing 7 was performed so as to cover the surface of the overlay welding portion. Silver brazing was performed by a torch brazing method using an Ag-Cu-Zn-Sn-Cd brazing material. As a result, the space between the titanium composite material of the titanium clad steel plate and the projection structure made of stainless steel was sealed with silver brazing, thereby preventing seawater from entering the welded portion inside.

(Example 2) In a structure in which the splash zone of a pier of an offshore structure shown in FIG. 5 is covered with a titanium clad steel plate, a fender is attached in the splash zone as shown in FIG. FIG. 4 shows a detailed structure of the stainless steel projection structure for attaching the fender. The main structure for mounting the stainless steel projection structure was the same as that of Example 1, except that only the silver brazing was replaced with the petrolatum paste application 13. The petrolatum paste was applied by a method in which an appropriate amount was picked up by hand and applied to the applied portion by hand. A fender 15 was fixed to the bolt-shaped stainless steel projection structure 3 via a stainless steel nut 14.
The petrolatum paste application section 13 had sufficient hermeticity similar to silver brazing, and was able to prevent seawater from entering the inside. Further, since the application portion 13 is arranged to be protected by the fender 15, the durability of the application portion is further improved, and sufficient durability is obtained as in the case of silver brazing.

The fender 15 was made of hard rubber. To prevent corrosion of the stainless steel nut 14, the nut 14
And a cap 16 made of titanium was installed so as to cover the projection structure 3 made of stainless steel, and the inside 17 of the cap was filled with petrolatum paste. Thereby, corrosion of the nut 14 made of stainless steel could be prevented.

[0031]

As described above, according to the present invention, corrosion resistance can be secured by a compact stainless steel projection structure which can be easily applied to the surface of a steel structure covered with a titanium clad steel sheet. Then, installation of fenders becomes easier.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a portion in which a projection structure made of stainless steel is connected to a titanium clad steel sheet coated structure of the present invention.

FIG. 2 is a cross-sectional view of a portion in which a projection structure made of stainless steel is connected to the titanium clad steel sheet coated structure of the present invention.

FIG. 3 is a cross-sectional view of FIG. 2 when a shoulder is not provided on the stainless steel protrusion structure.

FIG. 4 is a cross-sectional view of a portion in which a stainless steel projection structure is connected to the titanium clad steel sheet coated structure of the present invention, and further a fender is connected.

FIG. 5 is an overall view of the marine structure of the present invention.

FIG. 6 is an overall sectional view of a mounting portion of the fender according to the present invention.

[Description of Signs] 1 Steel structure 2 Titanium-clad steel plate 3 Stainless steel protrusion structure 4 Base plate 5 Welding part between steel structure and stainless steel protrusion structure 6 Overlay welding part 7 Silver brazing part 8 Notch 9 Welded part between base plate and stainless steel projecting structure 10 Same as above 11 Welded part between steel structure and base plate 12 Titanium clad steel plate with stepped part Titanium plate bridging each other 13 Petrolatum paste coated part 14 Stainless steel Nut 15 Fender 16 Titanium cap 17 Corrosion inhibitor filling part 18 Washer 19 Steel base material of titanium clad steel plate 20 Titanium clad material of titanium clad steel plate 31 Pier 32 Seaside 33 Splash zone (Titanium clad steel plate coated) 34 Sea Chubu

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B23K 9/23 B23K 9/23 H // B23K 103: 14 103: 16 (72) Inventor Koji Honma 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Division (72) Inventor Kazumi Matsuoka 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Division

Claims (7)

[Claims] 1. A structure in which the whole or a part of the surface of a steel structure is covered with a titanium-clad steel plate, a region where the titanium-clad steel plate is cut off is provided in a part of a region covered with the titanium-clad steel plate, A stainless steel projection structure is arranged so as to be connected to a steel structure in the cut area, and the steel structure and the stainless steel projection structure are welded to each other, and further cut off of the cut titanium clad steel sheet. The notch formed by the three members of the steel base material, the steel structure, and the stainless steel projection structure of the titanium clad steel plate at the end face is welded by overlaying so as not to contact the titanium clad material of the titanium clad steel plate. Further, the cladding weld portion is covered including a dissimilar joint portion between the titanium cladding material of the titanium clad steel sheet and the steel base material and a joint boundary between the stainless steel projection structure and the cladding weld portion. A titanium clad steel sheet coated structure characterized by being brazed with silver as described above. 2. A steel structure in which the whole or a part of the surface is coated with a titanium-clad steel plate, a base plate is welded to a part of the surface of the steel structure, and the titanium-clad steel plate is coated on the surface of the base plate. A region where the titanium-clad steel plate is cut off is provided on a part of the surface of the base plate, and a cut-out hole is provided in the cut-out region to penetrate the base plate in a region smaller than the cut-out region. A stainless steel projection structure is disposed so as to fit into the cut hole, the base plate and the stainless steel projection structure are welded and joined, and the titanium clad steel plate steel at the cut end face of the cut titanium clad steel plate is further cut. Notch formed by three members: base material, base plate, and stainless steel projection structure Part is welded so as not to contact the titanium cladding of the titanium clad steel sheet, and furthermore, the dissimilar joint between the titanium cladding material of the titanium clad steel sheet and the steel base material and the stainless steel projection structure and the overlay welding part A titanium clad steel sheet-coated structure characterized by being brazed with silver so as to cover the weld overlay including the joint boundary of (1). 3. A steel structure in which a whole or a part of the surface is coated with a titanium-clad steel plate, a base plate is welded to a part of the surface of the steel structure, and the titanium-clad steel plate coating is formed on the surface of the base plate. A region where the titanium-clad steel plate is cut off is provided on a part of the surface of the base plate, and a stainless steel projection structure is arranged so as to be connected to the base plate in the cut region, and the base plate and the stainless steel The notch formed by welding the titanium-clad steel plate with the protruding structure made of the titanium clad steel plate at the cut end surface of the titanium-clad steel plate, the base plate, and the protruding structure made of stainless steel. Overlay welding so that it does not contact the titanium clad material of the clad steel sheet, It is characterized in that it is formed by silver brazing so as to cover the overlay welding portion including the dissimilar joining portion between the welding material and the steel base material and the joining boundary between the stainless steel projection structure and the overlay welding portion. Titanium clad steel sheet coated structure. 4. The titanium clad steel sheet coated structure according to claim 1, wherein a petrolatum paste is applied instead of silver brazing. 5. The titanium clad steel sheet coated structure according to claim 4, wherein the petrolatum paste-coated portion is covered with another structure connected via a stainless steel projection structure. 6. A shoulder is provided near the end of the stainless steel projection structure on the connection side with the steel structure so that the plane of the shoulder is on the same plane as the surface of the titanium clad steel sheet. The titanium clad steel sheet coated structure according to claim 1, wherein the structure is constituted. 7. A stainless steel projecting structure forms a male screw, and another structure is fixed by connecting a stainless steel nut to the male screw portion, and titanium is used to cover the stainless steel nut. 7. The titanium clad steel sheet coated structure according to claim 1, wherein a cap is arranged, and the inside of the cap is filled with an anticorrosive.