JP3586358B2 - Titanium clad steel plate coated structure - Google Patents

Description

[0001]
TECHNICAL 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]
[Prior art]
Titanium is used in chemical plants and aircraft parts because of its excellent corrosion resistance, and its use is expanding, but its high cost 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.
[0003]
Taking steel pillars in offshore structures as an example, the seashore and underwater parts of the pillars are each subjected to corrosion treatment, but those exposed to the atmosphere while being wet with seawater called splash zones are usually Cannot sufficiently prevent corrosion. Therefore, a means for preventing corrosion by covering with a titanium clad steel plate so as to surround the four circumferences of the pillar in the splash zone of the pillar is taken.
[0004]
The thickness of the titanium composite material of the titanium clad steel sheet is usually small because titanium is an expensive metal. Therefore, when the ship comes into direct contact with the titanium clad steel plate on the surface of the offshore structure, the titanium cladding material is easily damaged, and seawater enters from that portion, and the corrosion of the steel structure inside proceeds. . In order to prevent this, it is effective to install fenders around the offshore structure. 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 titanium cladding of titanium clad steel sheet, corrosion progresses from inside the steel sheet when seawater enters inside at the welded part of the end face of titanium clad steel sheet, etc. Requires attention, for example, a welding structure as disclosed in JP-A-5-185237. Therefore, the structure of the splash zone covered with the titanium-clad steel sheet is simplified, and no protruding structure that is likely to cause seawater to enter the inside of 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 heterogeneous 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, etc. Is produced in a large amount, which makes the weld metal embrittleable, so that it may be said that welding is impossible.
[0006]
Therefore, conventionally, a projecting structure is welded to the sea surface that is not covered with a titanium clad steel plate above the splash zone, and an extension is further connected from the projecting structure, and a fender is fixed to a tip of the extension. The way was being taken.
[0007]
[Problems to be solved by the invention]
Thus, a method of laying a fender by providing a projection structure in a portion not covered with a titanium clad steel plate, providing a projection structure in a portion not covered with a titanium clad steel plate, and further providing an extension portion. In the above, since the external force acting on the fender acts on the projection structure as a large moment due to the presence of the extension, it was necessary to design the marine structure and the projection structure to be strong and large. The present invention provides a protruding structure in a portion covered with a titanium clad steel sheet, further does not expose a corrosive steel portion in the vicinity of the protruding structure, does not penetrate seawater, and has no fragile layer. An object of the present invention is to provide a marine structure having a structure and thereby solve the above-mentioned problems.
[0008]
[Means for Solving the Problems]
The gist of the present invention is:
(1) In a steel structure in which all or part of the surface is covered with a titanium-clad steel plate, a region where the titanium-clad steel plate is cut is provided in a part of a region where the titanium-clad steel plate is coated, and in the cut region, A stainless steel projection structure is arranged so as to be connected to a steel structure, and the steel structure and the stainless steel projection structure are welded to each other, and further, a titanium clad steel plate at a cut end face of the cut titanium clad steel plate. The notch formed by the three members of the steel base material, the steel structure and the stainless steel protrusion structure is welded by overlaying so as not to contact the titanium cladding material of the titanium clad steel plate, and furthermore, the titanium clad steel plate Silver solder to cover the welded joint including the dissimilar joint between the titanium composite material and the steel base material and the joint boundary between the stainless steel projecting structure and the weld overlay. Titanium clad steel plate coating structure characterized by comprising poppy.
[0009]
(2) In a steel structure in which all or 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, and the titanium-clad steel plate coating covers the surface of the base plate. Providing a region where the titanium clad steel plate is cut off on a part of the surface of the base plate, providing a cut hole penetrating the base plate in a region smaller than the cut region in the cut region, A stainless steel projection structure is arranged so as to fit into the hole, the base plate and the stainless steel projection structure are welded to each other, and further, a steel base of the titanium clad steel plate at the cut end face of the cut titanium clad steel plate. Material, base plate and stainless steel projection structure Welded so as not to come in contact with the titanium clad material of the clad steel sheet, and furthermore, the joining boundary between the dissimilar joint between the titanium clad material of the titanium clad steel sheet and the steel base material and the welded joint between the stainless steel projecting structure and the cladding welded part A titanium clad steel sheet coated structure characterized by being brazed with silver so as to cover the build-up welded portion.
[0010]
(3) In a steel structure in which all or 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, and the titanium-clad steel plate coating covers 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. The notch formed by the three members of the steel base material, the base plate and the stainless steel projection structure of the titanium clad steel plate at the cut end face of the titanium clad steel plate which has been welded to the structure and further cut away, is formed by the titanium clad steel plate Weld overlay so that it does not come in contact with the titanium cladding material of A titanium-clad steel sheet characterized by being brazed with silver so as to cover the overlay welding portion including a heterogeneous joining portion with the base material and a joining boundary between the stainless steel projection structure and the overlay welding portion. Coated structures.
[0011]
(4) The titanium clad steel sheet-coated structure according to any one of (1) to (3), wherein a petrolatum paste (JIS Z1903) is applied instead of silver brazing.
[0012]
(5) The titanium clad steel sheet-coated structure according to (4), wherein the petrolatum paste-applied portion is coated with another structure connected via a stainless steel projection structure.
[0013]
(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 this shoulder is configured to be 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:
[0014]
(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 a titanium cap for covering the stainless steel nut is provided. The titanium-clad steel sheet-coated structure according to any one of (1) to (6), wherein the structure is arranged and the inside of the cap is filled with an anticorrosive. It is.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Titanium can be connected by welding to metals similar to titanium, but welding of dissimilar metals such as titanium and steel makes the weld metal embrittled as described above, so the titanium sheet is directly coated on the surface of the steel structure. Can not be used for. Therefore, titanium clad steel sheets are used for the surface coating of structures used in a corrosive atmosphere. The titanium composite material used for the titanium clad steel sheet may be any one of one to three 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 is prevented from entering. For example, a method described in JP-A-5-185237 is adopted.
[0016]
Structures that are installed in a projecting manner on steel structures (hereinafter referred to as projecting structures) are exposed to the harsh environment necessary for corrosion protection of titanium coating on the steel surface. Can not be adopted. 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 projection needs 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. This has made it possible to achieve corrosion resistance and a strong connection with a structure. SUS304, SUS316L, or the like can be used as stainless steel.
[0017]
In the steel structure, the titanium clad steel sheet covering the surface of the portion to be connected to the stainless steel protrusion structure is cut off. The titanium-clad steel sheet may be cut in advance to its shape and used, or when combining multiple titanium-clad steel sheets to cover the surface, the titanium-clad steel sheet is not disposed only at the site where the stainless steel projection structure should be connected It can also respond by doing.
[0018]
In the first embodiment of the invention shown in FIG. 1, the stainless steel projection structure 3 is directly welded to the steel structure 1 at the weld 5. The cut portion of the titanium clad steel plate is made 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. The welded portion 6 is formed so as to fill the notch. At the cut end face of the titanium clad steel sheet, the welded portion 6 is joined only to the base material 21 of the titanium clad steel sheet, and not to the titanium laminated material 22. This is to prevent welding of different metals of titanium and iron, thereby preventing the embrittlement of the weld metal. 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, Y316L and the like.
[0019]
The welded portion 6 is formed 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 the silver brazing is performed at a melting temperature of 1100 ° C. or less, the material to be welded does not melt, and therefore, although the dissimilar metals of titanium and iron are in contact, the problem of embrittlement of the weld does not occur. Further, since the silver brazed portion is intended to cover the surface and has no structural strength, sufficient joining strength can be ensured in brazing.
[0020]
In the second embodiment of the present invention shown in FIG. 2, a base plate 4 is used for connecting the stainless steel projection structure 3. For example, in the case of a pier of an offshore structure, a thickness of the steel structure 1 is selected in order to secure strength as a pier, but the steel structure 1 is sufficient to support a moment generated by an 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.
[0021]
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 provided in the base plate as shown in FIG. The steel projection structure may be penetrated, and the two may be connected by welding. In the latter case, the provision of the groove 9 in the base plate does not form a bead pile like the welded portion 5 in FIG. 1 in the notch 8, which adversely affects the formation of the welded portion 6 and the silver brazed portion 7. Has the effect of not exerting In addition, by forming the welded portion 10, the joining strength between the base plate and the projection structure made of stainless steel can be further improved.
[0022]
The installation of the base plate creates a step on the steel structure. The titanium clad steel sheet needs to have 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 the titanium clad steel plates at the stepped portions, and the titanium plate 12 and the titanium clad material 22 of the titanium clad steel plate are joined by the TIG welding method to form a required titanium coating. Can be realized.
[0023]
The coating of the welded portion 6 can also be performed by applying 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 distillation under reduced pressure, and containing a corrosion inhibitor and the like as its main component. The anticorrosion function is exhibited by suppressing the 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.
[0024]
When a stainless steel structure is formed into 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.
[0025]
The shape of the stainless steel projection structure may be a cylinder as shown in FIG. 3. However, as shown in FIGS. 1 and 2, a shoulder is provided near the end on the connection side with the steel structure. The plane of the shoulder may be configured to be on the same plane as the surface of the titanium clad steel sheet. 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 reliable construction is facilitated.
[0026]
【Example】
(Example 1)
The pillars of the offshore structure were constructed in the shape of a square pillar using a 12 mm-thick steel sheet for general structural use, and the circumference of the pillar corresponding to the splash zone was covered with a titanium-clad steel sheet. 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 connection portion is as shown in FIG. SUS316L was used as the stainless steel material. The projection had a length of 120 mm, a base width of 60 mm, and a bolt diameter of 40 mm. A shoulder was provided on the projection so that the surface of the titanium clad steel sheet and the plane of the shoulder constituted the same plane. A general structural steel material having a thickness of 25 mm was used as a base plate. Through holes were formed in the base plate and grooves were provided on upper and lower surfaces, and stainless steel bolt-like projections were 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 to which the stainless steel projection structure was connected were welded to the steel structure as welds.
[0027]
The titanium clad steel plate 2 was joined to the surface of the steel structure 1 and the surface of the base plate 4. 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 a TIG welding method without using a welding material. Welding and joining achieve a sealed structure.
[0028]
The end face of the cut portion of the titanium clad steel plate on the base plate was arranged so as to form a cutout 8 having a width of 7 mm between the cut surface and the projection structure made of stainless steel. 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 cladding 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 weld overlay. Silver brazing was performed by a torch brazing method using an Ag-Cu-Zn-Sn-Cd-based brazing material. As a result, the space between the titanium composite material of the titanium clad steel sheet and the projection structure made of stainless steel was sealed with silver brazing, thereby preventing seawater from entering the welded portion inside.
[0029]
(Example 2)
In the structure in which the splash zone of the pier of the offshore structure shown in FIG. 5 is covered with the titanium clad steel plate, fenders were 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 attaching the stainless steel projection structure is the same as that of Example 1, and only the silver brazing is 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 as well as 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.
[0030]
The fender 15 was made of hard rubber. In order to prevent corrosion of the stainless steel nut 14, a titanium cap 16 was installed so as to cover the nut 14 and the stainless steel projection structure 3, 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]
【The invention's effect】
As described above, according to the present invention, it is possible to easily perform construction on the surface of a steel structure covered with a titanium-clad steel plate, and secure corrosion resistance by using a compact stainless steel projection structure to prevent corrosion. Installation of port materials becomes easy.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a portion where a stainless steel projection structure 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 projection 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.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 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 weld part 7 Silver brazing part 8 Notch part 9 Base plate Welded part between stainless steel projecting structure and stainless steel 10 Same as above 11 Welded part between steel structure and base plate 12 Titanium plate with stepped titanium clad steel plate 13 Crosslinked petrolatum paste applied part 14 Stainless steel nut 15 Fender Material 16 Titanium cap 17 Anticorrosive filler 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 (coated with titanium clad steel plate)
34 Mid-sea

Claims (7)

In a structure in which all or a part of the surface of the steel structure is covered with a titanium-clad steel sheet, a region in which the titanium-clad steel plate is cut is provided in a part of the region coated with the titanium-clad steel plate, and in the cut region, A stainless steel projection structure is arranged so as to be connected to a steel structure, and the steel structure and the stainless steel projection structure are welded to each other, and further, a titanium clad steel plate at a cut end face of the cut titanium clad steel plate. The notch formed by the three members of the steel base material, the steel structure and the stainless steel protrusion structure is welded by overlaying so as not to contact the titanium cladding material of the titanium clad steel plate, and furthermore, the titanium clad steel plate A silver filter covering the weld joint including the dissimilar joint between the titanium composite material and the steel base material and the joint boundary between the stainless steel projection structure and the overlay weld. Titanium clad steel plate coating structure characterized by comprising attach. In a steel structure in which all or 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, and the titanium-clad steel plate coating covers the surface of the base plate, 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 a smaller area than the cutout area in the cutout area, and fits into the cutout hole of the base plate. A stainless steel projection structure is arranged so as to fit together, 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 surface of the cut titanium clad steel plate, a base plate And the notch formed by the three members Welding is performed so that it does not come into contact with the titanium cladding material of the steel plate, and furthermore, the dissimilar joint between the titanium cladding material of the titanium clad steel plate and the steel base material, and the joint between the stainless steel projecting structure and the cladding weldment A titanium clad steel sheet-coated structure characterized by being brazed with silver so as to cover the weld overlay including a boundary. In a steel structure in which all or 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, and the titanium-clad steel plate coating covers the surface of the base plate, 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 provided. The notch formed of the titanium base metal, base plate, and stainless steel projection structure at the cut end face of the titanium clad steel plate, which has been cut off, is welded to the titanium clad steel plate. Overlay welding so that it does not come into contact with the material A titanium clad steel sheet-coated structure, which is formed by brazing silver so as to cover the overlay welding portion including the joining boundary between the dissimilar joint portion and the stainless steel projection structure and the overlay welding portion. . 4. The titanium clad steel sheet coated structure according to claim 1, wherein a petrolatum paste is applied instead of silver brazing. The titanium clad steel sheet coated structure according to claim 4, wherein the petrolatum paste-coated portion is coated with another structure connected via a stainless steel projection structure. A shoulder shall be provided in the vicinity of the end of the stainless steel projection structure on the connection side with the steel structure, and the shoulder shall be configured 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 any one of claims 1 to 5, wherein The stainless steel projection structure constitutes a male screw, another structure is fixed by connecting a stainless steel nut to the male screw portion, and a titanium cap covering the stainless steel nut is arranged, 7. The titanium clad steel sheet coated structure according to claim 1, wherein said cap is filled with an anticorrosive.

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