JPH1094875A - Method for welding titanium clad steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the method for welding a titanium clad steel plate excellent in sea water corrosion resistance. SOLUTION: A clad metal 2 of the titanium clad steel plate 1 is removed, base metals 3 from which the clad metal 2 are welded to each other by providing a groove in the base metal 3, a titanium spacer 5 is inserted into least both end parts of a part 4 where the clad metal including a base metal weld zone is removed so that the surface and side face of the spacer are matched with the surface and side face of the titanium clad steel plate 1 and the width of the spacer is method with the width of a part 4 where the clad metal, the surface is welded to the clad metals 2, the side face is subjected to plasma welding or TIG welding to the clad metals 2 and the part 4, and then a titanium backing plate 6 is welded to a spacer 5 and the clad metals 2 so as to cover the part 4 removing the clad metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A titanium clad steel sheet is a steel sheet in which titanium (called a composite material) having extremely excellent corrosion resistance is bonded to the surface of a steel sheet (called a base material) as a strength member. Since it is advantageous in terms of cost, its use is expanding in fields such as marine structures, chemical plants, and power plants, which have severe usage environments. However, it has not yet been used in large quantities due to the welding problems described below.

[0003] When a titanium clad steel sheet is welded by a usual method, a portion where a dissimilar metal of titanium and steel is melted (called a dissimilar material weld) is formed by a brittle intermetallic compound of iron and titanium, an oxide of titanium, Since a large amount of nitride is generated, the weld is likely to crack. Therefore, in welding titanium clad steel sheet, brazing in vacuum or diffusion bonding method of inserting an insert material that does not generate intermetallic compounds is used, but expensive vacuum equipment and insert material of precious metal are used. Therefore, there are problems that the cost is increased, the size is restricted, and welding at the construction site cannot be performed.

In order to solve such welding problems,
Conventionally, several methods have been proposed.

FIG. 2 shows a method of welding a titanium clad steel sheet described in JP-A-2-280969 or JP-A-2-280970. In FIG. 2, 1 is a titanium clad steel plate, 2 is a laminated material, 3 is a base material, 4 is a portion where the laminated material including a base material weld is removed, 5 is a titanium spacer, 6 is a titanium plate, 7 Represents a dissimilar material weld.

In the method shown in FIG. 2 (a), a groove is provided on a base material 3 from which the joining material 2 has been removed except for the joining material 2 at the butted portion of the titanium clad steel plate 1 to be welded. In the method of welding the material 3 and inserting a titanium spacer 5 of the same quality as the material 2 into the part 4 where the material including the base material weld is removed and welding it to the material 2 of the adjacent titanium clad steel plate 1 is there. In this case, depending on the welding conditions, there is a possibility that a dissimilar material weld 7 is formed on the side surface of the weld.

In FIG. 2 (b), after the titanium spacer 5 is inserted into the portion 4 from which the joining material including the base metal weld is removed by the method (a), the titanium spacer 5 is not welded. In this method, the titanium backing plate 6 is welded to the adjacent cladding material 2 of the titanium clad steel sheet 1 so as to cover the portion 4 from which the cladding material including the base metal weld has been removed.

[0008]

However, in the method shown in FIG. 2A, when a dissimilar material weld 7 is formed on the side surface and a brittle intermetallic compound or the like is generated, poor welding may occur. Since the interface between the titanium spacer 5 and the portion 4 from which the joining material including the base metal weld is removed is not welded, corrosive gas, seawater, or the like may intrude from the side surface and the corrosion resistance may be impaired.

Further, when a wide titanium clad steel plate is used, it is not easy to insert the titanium spacer 5 into the portion 4 including the base material welded portion where the joining material has been removed, with the same width. There is also a problem that the properties are significantly inhibited.

In the method shown in FIG. 2 (b), there is no possibility of poor welding due to the absence of dissimilar material welds.
As in the case of (1), since the interface between the titanium spacer 5 and the portion 4 from which the joining material including the base metal weld is removed is not welded, there is a possibility that corrosive gas, seawater, or the like may enter from the side surface.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and no intermetallic compounds or the like that cause poor welding at a welded portion are not generated. It is an object of the present invention to provide a simple method of welding a titanium clad steel sheet, which does not have a risk of impairing corrosion resistance.

[0012]

The above object is achieved by: (a) a step of removing a joining material (titanium) at a butt portion of a titanium clad steel plate to be welded; and (b) a mother of a portion from which the joining material has been removed. Providing a groove in the material (steel plate); (c) welding the base material provided with the groove; and (d) at least both ends of a portion of the bonded material including the base material welded portion where the joint material is removed. Part, the surface of which substantially coincides with the surface of the titanium-clad steel sheet, the side surface of which substantially coincides with the side surface of the titanium-clad steel sheet, and the width of which is the width of the removed portion of the composite material including the base metal weld. (E) inserting the titanium spacer into the laminated material of the adjacent titanium-clad steel plate on the surface and adjoining the titanium-clad steel plate on the side surface Welding a joint material and a portion of the joining material including the base material welded portion, and (f) applying a titanium backing plate so as to cover the removed portion of the joining material including the base material welded portion, A step of welding the titanium spacer and the adjacent titanium clad steel plate to a combined material, and performing dissimilar material welding on a side surface of the titanium spacer by plasma welding or TIG using a brazing material in an inert gas atmosphere. The problem is solved by a method of welding a titanium clad steel sheet, which is performed by welding.

[0013] In the main welding, since the base material is provided with a groove except for the joining material, there is no problem such as poor welding.

At least at both ends of the removed portion of the joining material including the base metal weld, the surface substantially matches the surface of the titanium clad steel sheet, the side surface substantially matches the side surface of the titanium clad steel plate, and the width thereof. Insert the titanium spacers so that they almost match the width of the part where the laminated material has been removed, and on the surface, the laminated material of the adjacent titanium-clad steel plate and on the side surface, the laminated material of the adjacent titanium-clad steel plate and the base material. If welding is performed on the portion where the joining material including the welded portion is removed, no intrusion of corrosive gas, seawater, or the like from the surface or side surface occurs at the portion where the titanium spacer is inserted.

Here, "substantially coincide" means that there is no problem in covering the surface with a titanium backing plate to be performed next, the titanium spacer can be inserted relatively easily, and the titanium spacer is so close that welding is possible. Means you are.

If the dissimilar material welding on the side surface of the titanium spacer is performed in an inert gas atmosphere, no oxide or carbonitride of titanium will be generated, and no intermetallic compound will be formed with iron or titanium. If a material is used and the welding is performed by plasma welding or TIG welding, which can be performed in a short time, the formation of a brittle intermetallic compound composed of iron and titanium is also significantly suppressed, so that welding defects such as cracks do not occur.

Further, by welding a titanium backing plate to a titanium spacer and an adjacent titanium clad steel plate so as to cover the removed portion of the bonding material including the welded portion of the base metal, welding of titanium is possible. Therefore, welding failure does not occur and corrosion resistance of the entire welded portion can be secured. In addition, when a titanium backing plate is used, the workability can be remarkably improved because the titanium spacers need only be inserted at both ends of the portion where the joining material including the base metal weld is removed.

[0018]

FIG. 1 shows an embodiment of a method for welding a titanium clad steel sheet according to the present invention. In FIG. 1, 1
Is a titanium clad steel plate, 2 is a mating material, 3 is a base material, 4 is a portion where a mating material including a base material weld is removed, 5 is a titanium spacer, 6 is a titanium plate, and 7 is a dissimilar material weld. Represent. FIG. 1A shows a base material 3 except for a bonding material 2.
(B) shows a state after the titanium spacer 5 is inserted and welded into the part 4 from which the joining material including the base metal weld has been removed, and (c) shows a state after the base material welded. Represents a state after the portion 4 from which the bonding material including the above is removed is covered with a titanium backing plate 6 and welded.

First, as shown in FIG. 1A, the joining material 2 is removed from the butted portion of the titanium clad steel sheet 1 to be welded, and the base materials 3 from which the joining material 2 has been removed are separated by TI.
G weld.

Next, as shown in FIG. 1B, titanium spacers 5 are inserted into both ends of the portion 4 from which the joining material including the base metal weld has been removed, and the surface of the titanium Tanned and welded to the laminated material 2 of the steel sheet 1, and the laterally adjacent laminated material 2 of the titanium clad steel sheet 1
And the part 4 where the joining material including the base material weld is removed is Ar
TIG welding is performed using a brazing material while shielding the welded portion in an atmosphere of an inert gas such as He or He, or plasma welding is performed using a brazing material using Ar gas as a center gas in addition to the shielding gas. At this time, the brazing material is J
IS Z3261, JIS Z3262, JIS Z3
263, JIS Z3264, JISZ3265, JI
S Z3266, JIS Z3267, JIS Z32
68 or the like can be used. Further, Sn or Zn may be added to the brazing material.

Finally, as shown in FIG. 1C, a titanium backing plate 6 is provided so as to cover the portion 4 from which the joining material including the base metal weld has been removed. Lap fillet welding is performed on the composite material 2 of the clad steel sheet 1 using a titanium or titanium alloy solution.

The method of the present invention can be applied to any type of titanium clad steel sheet. In addition, when the base material is welded to each other in the method of the present invention, if the steel sheet side of the titanium clad steel sheet is adhered to the surface of the structure by welding or the like, a structure having a surface covered with titanium and having excellent corrosion resistance can be constructed.

[0023]

Since the present invention is configured as described above, no intermetallic compounds or the like that cause poor welding at the welded portion are not generated, and the penetration of corrosive gas or seawater or the like is prevented. It is possible to provide a simple method for welding a titanium-clad steel sheet without the risk of impairing the corrosion resistance.

If the surface of the offshore structure is covered with a titanium clad steel sheet by applying the welding method of the present invention, a structure having excellent seawater corrosion resistance can be constructed.

[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 Japanese Patent Application Laid-Open No. 280969/1990,
It is a figure which shows the welding method of the titanium clad steel plate described in 80970 gazette.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Titanium clad steel plate 2 Laminated material (titanium) 3 Base material (steel plate) 4 Part from which the laminated material including base material weld was removed 5 Titanium spacer 6 Titanium backing plate 7 Dissimilar material weld

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Takano 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Tetsuo Sakiyama 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan (72) Inventor Takashi Matsuno 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (1)

[Claims] 1. A step of removing a joining material (titanium) at a butt portion of a titanium clad steel plate to be welded; and (b) forming a groove on a base material (steel plate) at a portion where the joining material has been removed. (C) a step of welding the base material provided with the groove, and (d) a surface of the titanium at least at both ends of a portion where the joining material including the base material weld is removed. The surface of the titanium clad steel plate substantially coincides with, the side surface substantially coincides with the side surface of the titanium clad steel plate, and the width of the titanium substantially coincides with the width of the removed portion of the joining material including the base metal weld. (E) inserting the titanium spacer into the laminated material of the adjacent titanium clad steel plate on the surface, and including the laminated material of the adjacent titanium clad steel plate and the base material weld on the side surface. (F) welding a titanium backing plate to cover the removed portion of the joining material including the base material welded portion with the titanium spacer and the adjacent titanium. A step of welding to a clad material of a clad steel sheet, wherein the dissimilar material welding on the side surface of the titanium spacer is performed by plasma welding or TIG welding using a brazing material in an inert gas atmosphere. Welding method for clad steel sheet.