JPH10328839A - Welding method for titanium clad steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method for titanium clad steel plate having excellent workability. SOLUTION: The surface of a steel structure 1 is covered with a titanium clad steel plate (called as a clad) making the clad metal 3 the surface and providing a gap, fillet welding 5 is executed to the base metal 4 of the clad 2 existing in both sides of the gap and the steel structure 1 exposing in the bottom part of the gap, and at least the end part of the gap and the bottom part of the gap in its vicinity part are flattered. And the titanium spacer 7 equal to about the shape of the gap is inserted into the gap after flattening the bottom part, welding 8 is executed to the clad metals 3 of the adjacent clad 2 in the surface of the titanium spacer 7, plasma or TIG welding 9 is executed to the clad 2 and the bottom part 6 of the flattered gap in the end part side surface under an inert gas using a pure Ag hot flux, the whole surface of the gap is covered with a titanium strop 10, and fillet welding 11 is executed to its periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of welding a titanium clad steel sheet, and more particularly to a method of welding a titanium clad steel sheet to a surface of a steel structure for corrosion protection.

[0002]

2. Description of the Related Art Titanium has very good corrosion resistance, and its use is expanding in fields such as marine structures, chemical plants, power plants, and environmental plants which are placed under severe corrosive environments.

[0003] In the field of huge structures such as marine structures, the production of structures themselves with expensive titanium requires enormous costs. Therefore, a titanium plate is attached to the surface of a structure made of inexpensive steel. A method of welding a titanium clad steel sheet in which a titanium sheet as a joining material is joined to the surface of a steel sheet of a base metal or a base material to prevent corrosion of a structure is being studied. In particular, in recent years, a weak intermetallic compound or titanium carbonitride is formed in a portion where dissimilar metals of titanium and iron are melted (called a dissimilar material weld), and welding defects such as cracks are generated. Titanium-clad steel sheets that can be welded to a structure using a base steel sheet have attracted attention. Further, since the titanium clad steel sheet can maintain its strength with the steel sheet, the thickness of the titanium of the laminated material can be reduced to the minimum thickness that can ensure the corrosion resistance, so that there is also a cost advantage.

However, even if a titanium clad steel sheet is used,
Therefore, in order to cover the surface of the steel structure without any gap, it is necessary to weld titanium clad steel plates to each other. At that time, the above-mentioned dissimilar material welds are generated, so that problems such as welding cracks cannot be completely avoided.

For this reason, various methods have been proposed for welding titanium clad steel sheets. For example, there is a brazing method in a vacuum or a diffusion bonding method in which an insert material is inserted so as not to generate an intermetallic compound, but the use of expensive vacuum equipment or a precious metal insert material increases the cost, and the size is restricted. There is a problem that welding at the construction site is not possible, and it cannot be applied to huge structures.

As a method applicable to a huge structure, Japanese Patent Application Laid-Open No. 2-280969 and Japanese Patent Application Laid-Open No. 2-280970
Japanese Patent Laid-Open Publication No. 2000-133, encloses a method for welding titanium clad steel sheets to each other, excluding a joint material at a butt portion, providing a groove there, welding a base material, and inserting a titanium spacer of the same quality as the joint material into the welded portion. In addition, a method has been proposed in which the surface is further covered with a titanium plate. In either case, the base material and the titanium spacer are not joined to each other, so if used in the splash zone of offshore structure pillars, seawater will enter through gaps and cause corrosion of the base material, or depending on welding conditions. Has the problem that the above-mentioned welding cracks occur.

Therefore, Japanese Patent Application Laid-Open Nos. 5-185237 and 6-15453 propose the following methods in order to solve the problems of the methods described in the above-mentioned Patent Literatures.

FIG. 4 shows a method for welding a titanium clad steel sheet described in Japanese Patent Application Laid-Open No. 5-185237. In the figure,
(A) shows the state after welding the base metal 4, (b) shows the state after welding by inserting the spacer 13 of titanium clad steel plate into the cut 15 at the end of the base metal weld 12, and (c) )
Is the base metal weld 12 and its surroundings
0 indicates the state after welding and welding.

First, as shown in (a), the joining material 3 is removed from the butted portion of the titanium clad steel plate 2 to be welded, and the base material 4 from which the joining material 2 has been removed is provided with a groove and the end thereof. After the cut 15 is made, the base materials 4 are welded together. Next, as shown in FIG.
A spacer 13 made of a titanium clad steel plate having the same quality as that of the titanium clad steel plate 2 to be welded is inserted into the notch 15 at the end of No. 2 and welded. At this time, the dissimilar material welding in which the titanium and the steel are melted on the end side surface of the spacer 13 of the titanium clad steel plate is performed by plasma welding or TIG welding using an Ag-Cu-based material in an inert gas atmosphere. The end dissimilar material welded portion 14 is formed. Finally, as shown in (c), the surface of the titanium clad steel plate 2 adjacent to the base metal weld 12 and the surface of the titanium clad steel plate spacer 13 inserted into the cut 15 are made of titanium of the same quality as the composite material 3. Filling plate 10 is welded by fillet welding so as to cover the entire base metal weld 12.

In this method, a titanium clad steel plate is used for the spacer, and the side surface of the end is also welded after the spacer is inserted, so that corrosive substances such as seawater do not enter the gap. In addition, the dissimilar material welding on the side surface of the end portion after the insertion of the spacer is performed by Ag-Cu
Since the welding is performed by the plasma welding or the TIG welding using the system melting material, an intermetallic compound of titanium and iron and a carbonitride of titanium are not generated, and welding defects such as welding cracks do not occur.

In the step (a) of welding the base materials to each other, if the base steel plate of the titanium clad steel plate is joined to the surface of the steel structure by welding or the like, the surface is covered with titanium without any gaps, so that the corrosion resistance is improved. An excellent steel structure can be manufactured.

[0012]

However, according to the methods described in JP-A-5-185237 and JP-A-6-15453, the joining material of the titanium clad steel sheet is removed before welding, Complicated work such as providing a groove or a cut in the removed base material must be performed, and workability is significantly impaired.

The present invention has been made in order to solve such problems, and provides a method of welding a titanium clad steel sheet excellent in workability and capable of covering the surface of a steel structure using a titanium clad steel sheet as it is. The purpose is to do.

[0014]

The object of the present invention is to (a) cover the surface of a steel structure with a titanium clad steel plate with a gap provided so that a joining material (titanium) comes to the surface, and to cover both sides of the gap. Base material of the titanium clad steel sheet (steel sheet)
And (b) after the fillet welding, flattening the gap bottom at least at the end of the gap and in the vicinity thereof. And (c) in the flattened gap at the bottom,
(D) inserting the inserted titanium spacer into the laminated material of the adjacent titanium-clad steel plate on the surface thereof, and inserting the titanium spacer on the end side surface thereof. Welding the clad steel plate and the flattened gap bottom, and (e) covering the entire surface of the gap after the welding with a titanium plate, and welding the periphery with fillet welding, The problem is solved by a method of welding a titanium clad steel plate by performing welding on the end side surface of the titanium spacer by plasma welding or TIG welding using a pure Ag solution in an inert gas atmosphere.

First, the surface of the steel structure is covered with a titanium-clad steel plate with a gap provided so that the titanium of the composite material comes to the surface, and the base material of the titanium-clad steel plate on both sides of the gap is covered with the bottom of the gap. If fillet welding is performed with the exposed steel structure, the titanium clad steel sheet can be used as it is without removing the bonding material or making a groove or notch in the base material after removing the bonding material. Workability can be significantly improved. Further, since the welding between the titanium clad steel sheet and the steel structure is welding between steels, there is no problem such as welding cracks.

The width of the gap may be appropriately selected according to the ease of welding work and the size of the titanium spacer to be inserted thereafter.

Next, in the gap after the fillet welding, at least the end portion and the bottom of the gap near the end portion are flattened, and after inserting a titanium spacer having substantially the same shape as the gap shape,
If the surface of the titanium spacer is welded to the adjoining material of the adjacent titanium clad steel plate and the end side surface is welded to the titanium clad steel plate and the flattened gap bottom, the surface and the end side surface of the part where the titanium spacer is inserted No corrosive material can penetrate through. At this time, if the welding of the side surface of the end is performed by plasma welding or TIG welding using a pure Ag solution in an inert gas atmosphere, the intermetallic compound of titanium and iron or the titanium No carbonitride is generated, and no problems such as welding cracks occur. Also, since the bottom of the gap after the fillet weld is flattened, the titanium can be easily inserted into the gap of the spacer.

In the present invention, the basic idea is to protect the side surface of the gap from corrosion by a titanium spacer and to protect the surface of the gap from corrosion by a titanium plate. It is not necessary to insert the gap over the entire length, and it is sufficient to insert the gap from the gap end to such an extent that the above object can be achieved. Therefore, the end of the gap and the bottom of the vicinity thereof may be flattened by a length corresponding to the length. If the shape of the titanium spacer to be inserted therein is completely equal to the shape of the flattened gap, it becomes very difficult to insert the spacer.

Finally, the entire surface of the gap is completely covered with titanium by covering the entire surface of the gap after welding with a titanium plate and welding the periphery with a spacer of titanium or a composite material of a titanium clad steel plate. Therefore, it is possible to impart excellent corrosion resistance to the steel structure.

[0020]

FIG. 1 shows an embodiment of a method for welding a titanium clad steel sheet according to the present invention. In the figure, the titanium clad steel plate 2 covering the steel structure 1 on the near side is omitted.

First, as shown in FIG. 2A, the surface of a steel structure 1 is covered with a titanium clad steel plate 2 with a gap provided so that a laminated material 3 comes to the surface. And the steel structure 1 is fillet welded to form a fillet weld 5 between the base metal and the steel structure. In this case, fillet welding is performed so that the welded portions of the base material 4 of the titanium clad steel plate 2 on both sides of the gap and the steel structure 1 exposed at the bottom of the gap overlap each other. Then, the fillet welds that overlap each other are flattened to form a flattened gap bottom 6.

Next, as shown in FIG. 2 (b), a titanium spacer 7 of approximately the same shape is inserted into the flattened gap at the bottom, and the surface is sealed to the laminated material 3 of the adjacent titanium clad steel plate 2. Welding forms the surface weld 8 of the titanium spacer. Then, on the side surface of the end where the dissimilar material welding of titanium and iron is performed, the titanium clad steel plate 2 and the flattening gap bottom 6 are welded by plasma welding or TIG welding using pure Ag solvent in an inert gas atmosphere. An end dissimilar material weld 9 of the spacer is formed.

Finally, as shown in FIG. 3 (c), the entire surface of the gap after welding is covered with a titanium abutment plate 10, and the periphery thereof is covered with a titanium spacer 7 and a laminated material 3 of a titanium clad steel plate 2.
Then, a fillet welded portion 11 of the titanium plate is formed.

According to the above-described method, it is not necessary to remove the laminated material of the titanium clad steel sheet, or to provide a groove or a cut in the base material after removing the laminated material, and welding cracks are generated in the dissimilar material welded portion. Without this, the surface of the steel structure can be covered with the titanium clad steel sheet.

According to such a method, for example, a steel structure having the following shape can be covered with a titanium clad steel plate.

FIG. 2 shows an example in which a steel structure is covered with a titanium clad steel sheet according to the method of the present invention. In the drawing, (a) shows an external view, and (b) shows an enlarged view of a portion A in (a).

This is an example in which a titanium clad steel plate 2 is welded to a square steel structure 1 by the method shown in FIG. At the corner, a titanium clad steel plate 2 bent at a right angle is used.

FIG. 3 shows another example in which a steel structure is covered with a titanium clad steel sheet according to the method of the present invention. In the drawing, (a) shows an external view, and (b) shows an enlarged view of a portion B in (a).

This is an example in which a titanium clad steel sheet 2 bent by roll bending is welded to the surface of a steel pipe by a method shown in FIG. 1 for a steel pipe pile used in seawater.

In each case, all of the welding, for example, T
It can be performed by IG welding. In particular, the dissimilar material weld 9 at the end of the titanium spacer where the dissimilar material welding of titanium and iron is performed
May be performed, for example, using a pure Ag solvent in an Ar gas atmosphere. Further, the flattening of the gap welding portion can be performed by a grinder or the like.

[0031]

Since the present invention is configured as described above, it is possible to provide a method of welding a titanium clad steel sheet excellent in workability, which can cover the surface of a steel structure using the titanium clad steel sheet as it is. .

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a method for welding a titanium clad steel sheet according to the present invention.

FIG. 2 is a diagram showing an example in which a steel structure is covered with a titanium clad steel sheet according to the method of the present invention.

FIG. 3 is a view showing another example in which a steel structure is covered with a titanium clad steel sheet according to the method of the present invention.

FIG. 4 is a view showing a method of welding a titanium clad steel sheet described in Japanese Patent Application Laid-Open No. 5-185237.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Steel structure 2 Titanium clad steel plate 3 Laminated material (titanium) 4 Base material (steel plate) 5 Fillet weld between base material and steel structure 6 Flattening gap bottom 7 Titanium spacer 8 Titanium spacer surface weld 9 Titanium spacer end dissimilar material weld 10 Titanium backing plate 11 Titanium backing plate fillet weld 12 Base metal weld 13 Titanium clad steel plate spacer 14 Titanium clad steel spacer end dissimilar material weld 15

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Nobuo Kitamura 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (1)

[Claims] (A) The surface of a steel structure is covered with a titanium clad steel plate with a gap provided so that a composite material (titanium) comes to the surface, and a base material of the titanium clad steel plate () on both sides of the gap is provided. (B) after the fillet welding, flattening at least an end of the gap and a bottom of the gap at the vicinity of the end thereof and the steel structure exposed at the bottom of the gap; (C) a step of inserting a titanium spacer having substantially the same shape into the flattened gap at the bottom; and (d) inserting the inserted titanium spacer into its adjacent surface on its surface. Welding the titanium clad steel sheet to the laminated material and, on the side surface of the end, the titanium clad steel sheet and the flattened gap bottom; And welding the periphery of the titanium spacer to the end side surface of the titanium spacer by plasma welding or TIG using a pure Ag material in an inert gas atmosphere. A method for welding titanium clad steel sheets by welding.