KR20070122149A - Welded structure - Google Patents

Abstract

A welded structure is provided to prevent brittle cracks from propagating by disposing a welded zone that connects bonding plates to each other at a predetermined region other than a portion between a welding seam and a bonded plate. A welded structure comprises a first bonding plate, which is obtained by welding two metal plates, and a second bonding plate, which is bonded on the first bonding plate through a welding process. A welding seam(6) between the two metal plates extends up to a zone around which the first and second bonding plates are bonded to each other. In the extension direction of the welding seam, the welding seam does not make contact with the second bonding plate. A welded zone that connects the first bonding plate to the second bonding plate is disposed in a predetermined region other than a region between the welding seam and the second bonding plate.

Description

Welded structure {WELDED STRUCTURE}

1A is a plan view of a container ship.

FIG. 1B is a view along the line b-b of FIG. 1A.

FIG. 2A is an enlarged view of a portion indicated by arrow A in FIG. 1B.

FIG. 2B is a view along the line b-b of FIG. 2A.

FIG. 3A shows a welded structure according to a first embodiment of the invention, which corresponds to an enlarged view of the portion indicated by arrow A in FIG. 1B.

FIG. 3B is a view along the arrow b-b of FIG. 3A.

FIG. 3C is an enlarged view of a portion indicated by arrow c in FIG. 3B.

4A is a diagram illustrating welding in the weld structure according to the first embodiment, and corresponds to FIG. 3C.

FIG. 4B is a view along the line b-b of FIG. 4A.

FIG. 4C is a view along the arrow c-c line in FIG. 4A.

FIG. 4D is a view along the arrow b-b in FIG. 4A, illustrating another welding method.

FIG. 5A shows a case where a cover plate for blocking a hole is provided in the configuration of FIG. 3C.

FIG. 5B is a view along the line b-b of FIG. 5A.

FIG. 5C is a view along the line c-c of FIG. 5B.

6A shows a welded structure according to a second embodiment of the present invention.

FIG. 6B is a view along the line b-b of FIG. 6A.

FIG. 6C is a view along the arrow b-b in FIG. 6A, showing another welding method.

FIG. 7 is an enlarged view of the portion enclosed by the broken line A in FIG. 6A and illustrates the case where the depression is provided in the contact preventing member.

8 illustrates a case where the depression is not provided in the contact preventing member formed of mild steel.

FIG. 9A shows a welded structure according to a third embodiment of the present invention and corresponds to the view taken along the line b-b in FIG. 3A.

FIG. 9B is an enlarged view of a portion indicated by arrow b in FIG. 9A.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2004-232052 "Welding Structure with Excellent Fracture Resistance Fracture"

[Patent Document 2] Japanese Patent Application Laid-Open No. 2005-111501 "Welding structure excellent in brittle fracture propagation resistance"

[Patent Document 3] Japanese Unexamined Patent Publication No. 2005-319516 "Welding method and welded structure of a welded structure excellent in brittle crack propagation resistance"

[Patent Document 4] Japanese Patent Application Laid-Open No. 2005-131708 "Welding structure excellent in brittle crack propagation resistance and its welding method"

[Non-Patent Document 1] Japanese Society of Shipbuilding and Ocean Engineers No. 3, pages 73-74 (November 10, 2005) "Development of Ultra-Large Container Ships-Practical Use of New High Strength Ultra-thick Steel Plates"

The present invention relates to a welded structure that can secure its strength in a welded welded structure such as a container line or a bulk carrier. More specifically, the present invention relates to a welded structure in which the propagation can be stopped if a brittle crack occurs in the welded seam of the welded structure.

Container vessels, bulk carriers, and the like are welded structures that are welded and joined to a plurality of steel sheets and dried. Such a welded structure will be described with reference to the drawings by taking a container line as an example. In the case of the bulk carrier, the cross-sectional shape is different from the container line, but is almost the same as the welded structure.

FIG. 1A is a plan view of a container line, and FIG. 1B is a view along the line b-b of FIG. 1A. 2A is an enlarged view of the portion indicated by the arrow A in FIG. 1B, and FIG. 2B is a view along the arrow b-b line in FIG. 2A.

As shown in FIG. 1A, the upper deck 4 continues from the bow to the stern, and is welded to the outer shell 14 and the inner shell 16. The upper deck 4, the sheath outer plate 14 and the sheath inner plate 16 constitute a hull. In addition, as shown in FIG. 1B, a hatch coaming plate 2 is welded to the upper deck 4. The hatch coaming plate 2 has a function of increasing the strength of the hull and is one of the most important members in strength. Each of the upper deck 4, the sheath outer plate 14, the sheath inner plate 16, and the hatch coaming plate 2 is formed by joining a plurality of steel plates by welding.

As shown in FIGS. 1A and 1B, the container ship has a large dock 32 therein and a large opening 34 in the upper part of the dock. You cannot place it densely. Therefore, in the container ship, it is necessary to ensure the strength of the ship shell.

In order to secure the strength of a welded structure, such as a hull angle, it is a basic thing to secure the toughness of the welded joint part (for example, the welded joint part 6 of FIG. 2B) in a welded structure. However, when welding is performed by high heat input welding, such as electrogas welding, there exists a tendency for the toughness of a weld seam part to fall by a thermal effect. In addition, there may be a case where a defect exists in the weld seam. Therefore, there is a possibility that brittle cracking occurs due to these causes.

In the case where brittle cracks occur at the welded joints, for example, in FIG. 2B, the brittle cracks often deviate from the welded joints 6 to the steel base material 2a side due to the residual stress of the welded joint 6. . Such a propagation stop function can be obtained from a steel sheet having a sheet thickness of 50 mm or less.

However, it is pointed out that in steel sheets of higher plate thickness, brittle cracks propagate along the weld seam without escaping to the base metal side. For example, in the non-patent document 1 described above, in the high heat input welding joint portion of a high strength ultra-thick steel sheet having a plate thickness of 70 mm, brittle cracks go straight along the weld joint portion without escaping to the base metal side, and the propagation is not stopped, An experimental example in which an extreme steel sheet is divided is disclosed.

In particular, in recent years, the plate thickness of steel materials used for container ships has become thick with the enlargement of container ships. Specifically, a large vessel exceeding 6000TEU is dried, and the plate | board thickness of the steel material used for it is 50 mm or more, and the plate | board thickness of the steel material used by container ship of 8000TEU grade or more exceeds 70 mm.

When the plate thickness of the steel used is thick, the brittle crack generated at the weld seam is likely to propagate without escaping to the base metal side. It is preferable to assume the case where a brittle crack leads to the situation where it propagates through other parts beyond a weld seam. Therefore, it is preferable to assume the case where a brittle crack occurs in a weld seam, and to equip a ship with the function which stops the propagation of a brittle crack before reaching such a situation.

The propagation stop means of such a brittle crack is disclosed by patent documents 1-4, for example.

Patent Literature 1 describes that surface reinforcing steel having excellent brittle fracture characteristics is used as a reinforcing material provided to intersect the weld seam.

In Patent Document 2, a surface fine grained steel having excellent brittle fracture characteristics is used as a reinforcing material provided to intersect the weld seam, and a width greater than the bead width of the weld seam and the surface of the reinforcing material in the area where the weld seam and the reinforcing material intersect. Or it is described to perform welding which injects the range which has the length of 70% or more of plate | board thickness from the back surface completely.

Patent Document 3 describes that the vertical member and the weld metal of the region are cut out in the region where the brittle crack of the vertical member is to be stopped, and an arrester material having a specific plate thickness and plate length is inserted into the portion. It is.

In Patent Document 4, after removing a part of the weld seam portion of the region to stop the brittle crack, the weld portion is repaired and welded using a welding material excellent in fracture toughness, and a repair weld portion in the longitudinal direction of the weld seam portion is provided. It is described that the angle in the outer edge direction is 10 degrees to 60 degrees.

However, in the case of patent documents 1, 2, it is necessary to prepare a special surface layer fine steel. Moreover, in the case of patent document 3, it is necessary to use the expensive arrester material which has an arrest characteristic. In addition, in the case of patent document 4, the fine work which processes a repair welding part to a specific shape is required besides the work which cuts out a specific part.

Therefore, the objective of this invention is a welding structure which stops the propagation of a brittle crack by means different from patent documents 1-4, By simple processing, without using the expensive arrester material containing many alloys, It is an object of the present invention to provide a welded structure that stops propagation even when a brittle crack occurs.

The 1st invention of this application is made | formed by the following viewpoint. When welding a joining plate (for example, the hatch coaming plate 2 of FIG. 2B) including the welded joint to the joined plate (for example, the upper deck 4 of FIG. 2B), the welding seam of the joining plate ( For example, if the welded joint 6 of FIG. 2B is in contact with the welded portion of the bonded plate and the joined plate, brittle cracks propagated and generated at the welded joint penetrate the welded portion of the bonded plate and the joined plate, It is possible to spread. For this reason, the welded portion of the bonded plate and the joined plate may have low toughness due to heat input during welding, and the welded portion may become a propagation path. The present invention focuses on this point and stops brittle cracks that have propagated along the weld seam of the bonded plate at the boundary between the bonded plate and the joined plate.

That is, in order to achieve the said subject, according to the 1st invention of this application, it is equipped with the joining board which two metal plates are joined by welding, and the to-be-joined board joined by welding to the said joining board, and said two sheets In the welded structure in which the welded joint between the metal plates of the welding plate extends toward the to-be-joined plate to the vicinity of the joining position of the said joining board and the to-be-joined board, the said welded joint part and a to-be-joined board are a direction in which the said welded joint is toward a to-be-joined board. A welding structure is provided which is configured such that a welding portion for joining the joining plate and the joined plate does not exist between the welded seam portion and the joined plate without being contacted.

In the above configuration, there is no brittle crack propagation path such as a welded portion between the welded joint and the joined plate in the direction in which the welded joint faces the joined plate. Therefore, propagation of brittle cracks can be stopped at the boundary between the welded seam and the plate to be joined.

In addition, in the direction in which the welded seam faces the to-be-joined plate, it is expensive to prevent the welded seam and the to-be-joined plate from being present between the welded seam and the to-be-joined plate so that a welded part for joining the joining plate and the to-be-joined plate does not exist. It can be achieved simply without the need for Gorester steel.

As described above, according to the present invention, even when brittle cracking occurs by simple processing without using an expensive arrester material, the propagation can be stopped.

Moreover, 2nd invention of this application is made | formed by the following viewpoint. In a welded structure in which two joining plates (for example, two hatch-coaming plates 2a in FIG. 2B) including welded joints are welded, brittle cracks are assumed to propagate along the welded joint in the welding direction. . With this point in mind, in the second aspect of the invention, a hole penetrating the weld metal and the portion where the toughness is reduced due to heat input during welding is made to eliminate the propagation path of the brittle crack.

That is, in order to achieve the said subject, according to the 2nd invention of this application, in the welding structure containing the joining plate in which two metal plates are joined by welding, the welding seam extended between two metal plates is made in the middle. A welding structure is provided, characterized in that a hole penetrating the weld seam in the thickness direction of the joining plate is provided so as to divide at.

In the above configuration, since a hole penetrating the weld seam is provided so as to divide the weld seam extending between the two metal plates on the way, there is no brittle crack propagation path between the weld seam divided by the hole. Therefore, propagation of brittle cracks can be stopped between the divided weld seams.

In addition, forming the hole for dividing the weld seam can be easily achieved without the need for expensive Gorester steel.

As described above, the present invention can stop the propagation even when a brittle crack occurs by simple processing without using an expensive arrester material.

In addition, since the propagation of the brittle crack is stopped by forming a hole for dividing the weld seam, the present invention can also be applied to an already manufactured weld structure. For example, by forming a hole that penetrates the weld joint between two metal plates included in the manufactured weld structure, the manufactured weld structure can be provided with a brittle crack propagation stop function.

According to a preferred embodiment of the present invention, in the first invention, in the vicinity of the joining position in the joining plate, a hole penetrating in the thickness direction of the joining plate is formed between the weld seam and the joined plate, whereby The welded part for joining the joining plate and the to-be-joined plate does not exist between the welded joint part and the to-be-joined plate while the welded joint and the to-be-joined plate are not in contact with each other.

Thereby, a brittle crack propagation path | route, such as a welded part, does not exist between a welded joint part and a to-be-joined plate in the direction which a welded joint part faces a to-be-joined plate. Therefore, propagation of brittle cracks can be stopped by simple processing without using an expensive arrester material.

A cover member for blocking the opening of the hole is provided, and the cover member may be joined to at least one of the joining member and the member to be joined by a fillet weld.

In this way, the junction plate can be made watertight by closing the hole with the cover member.

In addition, since the fillet welding has a small length, the influence of the fillet welding on the propagation of the brittle crack is small. Therefore, even when the cover member is attached by fillet welding, propagation of the brittle crack can be stopped.

According to another embodiment of the present invention, in the first invention, a contact preventing member is interposed between the welded portion and the welded plate in the vicinity of the joining position, whereby the welded joint portion and the joined plate do not contact. The welding part which joins the said joining board and a to-be-joined plate does not exist between the said weld seam part and a to-be-joined board, however.

Thereby, a brittle crack propagation path | route, such as a welded part, does not exist between a welded joint part and a to-be-joined plate in the direction which a welded joint part faces a to-be-joined plate. Therefore, propagation of brittle cracks can be stopped by simple processing without using an expensive arrester material.

According to the present invention described above, the propagation can be stopped even if brittle cracking occurs by simple processing without using an expensive arrester material.

Other objects and advantageous features of the present invention will become apparent from the following description with reference to the accompanying drawings.

Preferred embodiment for implementing this invention is described based on drawing. In addition, the same code | symbol is attached | subjected to the part common in each drawing, and the overlapping description is abbreviate | omitted.

[First Embodiment]

FIG. 3A is an enlarged view of a portion indicated by arrow A in FIG. 1B and illustrates a case where the weld structure according to the first embodiment (corresponding to the first invention) of the present invention is applied to a hatch coaming and upper deck of a container ship. .

As shown in FIG. 3A, the weld structure according to the first embodiment is a structure obtained by welding the hatch coaming plate 2 to the upper deck 4 by welding.

FIG. 3B is a view along the arrow b-b line in FIG. 3A. As shown in FIG. 3B, the hatch coaming plate 2 is formed by welding two or more metal plates 2a (steel plates in this example) to face each other in cross section. On the other hand, the aggregate 8 as a reinforcing material extending in the direction transverse to the weld seam 6 is joined to the side surface of the hatch coaming plate 2 by fillet welding. The top plate 12 arranged in the horizontal direction is welded to the upper end of the hatch coaming plate 2.

The upper deck 4 is joined to the upper end part of the outer side shell 14 and the inner side inner plate 16 like FIG. 3A. The lower end of the hatch coaming plate 2 is joined to the upper deck 4 by welding.

The weld seam 6 of the hatch coaming plate 2 extends toward the upper deck 4 to the vicinity of the joining position of the hatch coaming plate 2 and the upper deck 4.

FIG. 3C is an enlarged view of a portion indicated by arrow c in FIG. 3B. As shown in FIG. 3C, according to the first embodiment, the welding seam 6 does not contact the upper deck 4 in the thickness direction near the joining position of the hatch coaming plate 2 and the upper deck 4. The hole 18 which is a space which penetrates into it is formed.

As described above, in the weld structure according to the first embodiment, the weld seam 6 is formed by the holes 18 of the hatch coaming plate 2 in the direction in which the weld seam 6 faces the upper deck 4. The welding part which joins the hatch coaming plate 2 and the upper deck 4 does not exist between the welding joint part 6 and the upper deck 4, without contacting (4). That is, due to the hole 18 of the hatch coaming plate 2, there is no brittle crack propagation path such as a welded portion between the weld seam 6 and the upper deck 4. As a result, the brittle crack propagated through the weld seam 6 can be stopped at the boundary between the weld seam 6 and the upper deck 4. In addition, in this application, a welded part is a concept including the part in which toughness fell by the weld metal and the thermal effect at the time of welding.

4A to 4D show the welding of the hatch coaming plate 2 and the upper deck 4. 4A to 4D, the weld seam 7 described later is omitted. FIG. 4A is the same as FIG. 3C, FIG. 4B is a view seen along the arrow b-b line of FIG. 4A, and FIG. 4C is a view seen along the arrow c-c line of FIG. 4A. As shown in FIG. 4B, in the range of the arrow A direction where the hole 18 does not exist, the hatch coaming plate 2 and the upper deck 4 are joined by the fillet weld 22. On the other hand, as shown in FIG. 4C, in the range of the arrow A direction in which the hole 18 exists, the hatch coaming plate 2 and the upper deck 4 are not welded. In addition, instead of the welding of FIG. 4B, as shown in FIG. 4D, in the range of the arrow A direction in which the hole 18 does not exist, the welding part 24 is extended to the inside of the hatch coaming 2 and the upper deck 4. As shown in FIG. It may be extended.

When the hatch coaming plate 2 is made watertight, the cover plate which closes the hole 18 can be attached to the hatch coaming plate 2 as follows.

FIG. 5A illustrates the case where the cover plate 26 is added to the configuration of FIG. 3C. FIG. 5B is a view along the arrow b-b line in FIG. 5A. FIG. As shown in FIG. 5B, the cover plate 26 is bonded to one side surface of the hatch coaming plate 2. Thereby, the hole 18 formed in the front-end | tip of the welding joint part 6 is closed. On the other hand, the cover plate 26 constitutes a cover member which closes the hole 18. The cover member may not be flat.

FIG. 5C is a view along the arrow c-c line in FIG. 5B. FIG. As shown in FIGS. 5A to 5C, the joining of these cover plates 26 and the hatch coaming plate 2 is performed by fillet welding indicated by reference numeral 22. The cover plate 26 is also joined to the upper deck 4 by fillet welding. The fillet weld 22 shown in FIG. 5A is omitted in FIGS. 5B and 5C, and the fillet weld 22 shown in FIG. 5B is omitted in FIGS. 5A and 5C, and the fillet shown in FIG. 5C. The weld 22 is omitted in FIGS. 5A and 5B.

Since fillet welding has a small square, the effect of fillet welding on the propagation of brittle cracks is small. Therefore, even when the cover plate 26 is attached by fillet welding, brittle cracks can be prevented from propagating from the weld joint 6 into the upper deck 4.

The positional relationship between the welded seam 6 of the hatch coaming plate 2 and the welded seam 6 'of the outer sheath 14 or the inner sheath 16 will be described.

In the conventional container ship, in order to make it safer, as shown to FIG. 2B, the position of the arrow A direction of the weld seam 6 and the weld seam 6 'was shifted.

On the other hand, in this embodiment, as shown in FIG. 3B, the position of the weld seam 6 and the weld seam 6 'direction of arrow A can be made the same. This is because, if the brittle crack occurs in the welded joint 6, the propagation of the brittle crack can be stopped at the boundary between the welded joint 6 and the upper deck 4 as described above.

Thus, in this embodiment, following position (1)-(3) is attained by being able to make the position of the arrow A direction of the weld seam 6 and 6 'the same.

(1) Design and construction can be carried out without minding the position of the weld seam 6 of the hatch coaming plate 2 and the position of the weld seam 6 'of the upper deck 4.

(2) The hatch coaming and upper deck 4 can be mounted on the dock as a block at the same time.

(3) In container ships in which the same structure is repeated every HOLD, parts can be unified.

On the other hand, in the related art, the lengths of the hatch coaming and the upper deck are irregular for each HOLD so that the positions of the weld joints 6 and 6 'are not the same.

3B, 3C, and 2B have shown the weld seam of the upper deck 4, but the weld seam 7 is abbreviate | omitted in another figure.

Second Embodiment

Next, the weld structure which concerns on 2nd Embodiment of this invention is demonstrated. Configurations other than those described below may be the same as in the first embodiment.

FIG. 6A is an enlarged view of the portion indicated by the arrow c in FIG. 3B, illustrating the weld structure according to the second embodiment. 6B is a view seen along the arrow b-b line in FIG. 6A.

As shown to FIG. 6A, FIG. 6B, the welding joint part 6 is made so that the welding joint part 6 may not contact the upper deck 4 in the vicinity of the joining position of the welding joint part 6 and the upper deck 4. The contact prevention member 28 is interposed between and the upper deck 4. The contact preventing member 28 can be formed of mild steel having high toughness, for example. In addition, the shape of the contact prevention member 28 may be a flat plate which made the corner of the four corners of the upper surface into the smooth curved shape, as shown to FIG. 6A and FIG. 6B.

In order to provide this contact preventing member 28, a hole penetrating in the thickness direction near the tip of the upper deck 4 side of the welded joint 6 in the hatch coaming plate 2 (not shown in FIGS. 6A and 6B). ) Is provided. The hole and the contact preventing member 28 may have the same cross-sectional shape and its size perpendicular to the penetrating direction of the hole. Alternatively, the contact preventing member 28 may have a cross-sectional shape perpendicular to the penetrating direction of the hole different from the hole, and a size of the cross section perpendicular to the penetrating direction of the hole may be smaller than the hole.

In the welding structure which concerns on 2nd Embodiment, in the direction which the welding joint part 6 faces the upper deck 4, the welding joint part 6 is the upper deck 4 between the welding joint part 6 and the upper deck 4. By providing the contact preventing member 28 so as not to touch), there is no brittle crack propagation path between the weld seam 6 and the upper deck 4. As a result, the brittle crack propagated through the weld seam 6 can be stopped at the boundary between the weld seam 6 and the upper deck 4.

6B, the contact prevention member 28 can be joined to the hatch coaming plate 2 and the upper deck 4 by the fillet welding part 22. As shown in FIG. Thereby, the clearance which becomes the passage of water between the contact prevention member 28, the hatch coaming plate 2, and the upper deck 4 can be prevented, and the hatch coaming plate 2 can be made watertight. As described above, since the fillet welding has a small square, the influence of the fillet welding on the propagation of the brittle crack is small. Therefore, even if the contact prevention member 28 is attached by fillet welding, the propagation of the brittle crack from the weld joint 6 to the upper deck 4 can be stopped. On the other hand, in the range where the contact preventing member 28 in the arrow A direction of FIG. 6B does not exist, the hatch coaming plate 2 and the upper deck 4 may be joined by welding similar to that of FIG. 4B or 4D. .

On the other hand, as shown in FIG. 6C, the contact preventing member 28 is formed by the fillet weld 22 for joining the hatch coaming plate 2 and the upper deck 4 to the hatch coaming plate 2 and the upper deck 4. ) May be bonded.

FIG. 7 is an enlarged view of the portion enclosed by the broken line A in FIG. 6A, and illustrates the case where the depression 28a is provided in the contact preventing member 28. In addition, the fillet welding part 22 is abbreviate | omitted in FIG.

In the second embodiment, preferably, the surface of the contact preventing member 28 facing the direction in which the weld seam 6 extends toward the upper deck 4, as shown in FIG. 7 (FIG. 7). In the example, the depression 28a is formed on the upper surface) to prevent the welding metal used for welding the hatch coaming plate 2 from being infiltrated into the contact preventing member 28. This depression 28a is formed smoothly. For example, the depression 28a is smoothly formed so that the depth of depression is the deepest in the center, and the depth of depression gradually becomes shallow as it goes to the periphery of the depression 28a in the center.

By forming this recessed part 28a, when welding the hatch coaming plates 2 to each other in the state which arrange | positioned the contact prevention member 28 as shown in FIG. 7, the weld metal from the welding joint part 6 will be recessed. It is accommodated in the 28, and can prevent the welding metal from infiltrating into the contact preventing member 28.

Moreover, by forming the recessed part 28a smoothly, the shape of the weld metal in the boundary of the welding joint part 6 and the contact prevention member 28 can be made smooth.

As a result, fatigue cracking can be prevented from occurring in the contact preventing member 28. Compare with the case of FIG. FIG. 8 shows the case where the depression 28a is not provided in the contact preventing member 28 formed of mild steel. In the case of FIG. 8, since the recessed part 28a is not formed, weld metal is infiltrated into the contact prevention member 28, and the weld metal of the welding metal part 6 and the contact prevention member 28 of the weld metal is prevented. You cannot adjust the shape. Therefore, there is a possibility that the shape of the weld metal is not smooth and stress concentration may occur, and the fatigue strength with respect to the cyclic load may decrease. On the other hand, in the example of FIG. 7, it is possible to suppress the penetration of the weld metal into the contact preventing member 28 by the depression 28a, and at the boundary between the weld seam 6 and the contact preventing member 28. Since the shape of a weld metal can be made smooth, it can prevent that stress concentration arises in the contact prevention member 28. FIG.

More preferably, the contact preventing member 28 is formed of a material (eg, ceramic) in which the weld metal does not penetrate. As a result, the penetration of the weld metal into the contact preventing member 28 can be suppressed more reliably, and the shape of the weld metal can be smoothed at the boundary between the weld joint 6 and the contact preventing member 28. On the other hand, the contact preventing member 28 may be formed of a material in which the weld metal does not penetrate without forming the depressions 28.

Further, preferably, the shape and dimensions of the contact preventing member 28 having the depression 28a are the same as in the case of Figs. 6A and 6B, so as to mount the hatch coaming plate (28). It almost coincides with the shape and dimensions of the hole 2b formed in 2). In this case, it is good to provide the insertion stand for inserting the contact prevention member 28 in the said hole 2b.

[Third Embodiment]

FIG. 9A is a view along the arrow b-b line in FIG. 3A and shows a case where the weld structure according to the third embodiment (corresponding to the second invention) of the present invention is applied to hatch coaming of a container line. As shown to FIG. 9A, the welding structure which concerns on 3rd Embodiment includes the structure which welded and joined two or more metal plates 2a (steel plate in this example) to the cross section.

FIG. 9B is an enlarged view of a portion indicated by arrow b in FIG. 9A. As shown in FIG. 9B, according to the third embodiment, the welding seam 6 extending between the two metal plates 2a is divided in the thickness direction of the hatch coaming plate 2 so as to be divided in the middle. A hole 29 penetrating the weld seam 6 is formed.

Thus, in the weld structure which concerns on 3rd Embodiment, since the hole 29 which penetrates the welding seam 6 is provided, brittle crack propagation between the welding seams 6 divided by the hole 29 is provided. The route does not exist. Thus, propagation of brittle cracks between the divided weld seams 6 can be stopped. Accordingly, the brittle cracks generated at the welded seam 6 and propagated through the welded seam 6 can be stopped between the divided welded seams 6.

In addition, since the propagation of the brittle crack is stopped by forming the hole 29 for dividing the weld seam 6, the present invention can be applied to an existing container line. For example, by forming a hole 29 penetrating the weld seam 6 between two metal plates 2a included in the existing container line, the existing container line can be provided with a brittle crack propagation function. Can be.

In addition, as mentioned above, in this application, a welded part is a concept including the part in which toughness fell by the weld metal and the heat effect at the time of welding. In the example of FIG. 9B, the welded seam 6 includes a weld metal portion 6a and a heat affected portion 6b whose toughness is lowered by the heat effect at the time of welding. Therefore, not only the weld metal part 6a but also the heat affected part 6b are divided into two by the hole 29. FIG.

Formation of the hole 29 can be performed by machining using a gas cutter or other suitable machine, for example. Therefore, it becomes possible to give a brittle crack propagation stop function without using a special steel material or a molten material.

Although the shape of the hole 29 is circular in the cross section perpendicular | vertical to the thickness direction of the hatch coaming plate 2 in the example of FIG. 9B, other suitable shapes, such as an ellipse, may be sufficient in the said cross section. In this case, preferably, the hole 29 has a shape in which the outer edge of the hole 29 is smooth in the cross section.

Although the dimension of the hole 29 in the direction (the left-right direction of FIG. 9B) which the cross sections of the metal plate 2a oppose each other is larger than the dimension of the welding seam 6 in the said direction, welding by a cross section defect The size of the hole 29 is determined so that the strength reduction of the structure is within the allowable range. In addition, the dimension of the hole 29 in the up-down direction of FIG. 9B may be about the same as the dimension of the hole 29 in the left-right direction of FIG. 9B.

On the other hand, as shown in FIG. 5C, the dimension of the welded seam 6 in the vertical direction of FIG. 5C increases from the left side to the right side of FIG. 5C in a cross section perpendicular to the thickness direction of the hatch coaming plate 2. The size of the hole 29 in the up and down direction in FIG. 5C may be increased like the welded joint 6, and may be constant over the left to the right in FIG. 5C.

In addition, when making the hatch coaming plate 2 watertight, the cover plate 26 which closes the hole 29 can be attached to the hatch coaming plate 2 similarly to 1st Embodiment. This cover plate 26 can be joined to the hatch coaming plate 2 by a fillet welding similarly to 1st Embodiment. When the hole 29 is provided in a position close to the upper deck, the cover plate 26 may be joined not only to the hatch coaming plate 2 but also to the upper deck by fillet welding.

[Other Embodiments]

The hatch coaming plate 2 and the upper deck 4 described above correspond to the bonded plate and the joined plate in the claims, respectively, but other members may be the bonded plate and the bonded plate. For example, the upper deck 4 of the container ship may be a joining board, the outer side shell 14 may be a joined board, the inner side board 16 may be a joined board, and the upper deck 4 may be a joined board.

Even if the above-mentioned hole 18 and the contact prevention member 28 are shapes or dimensions other than the shape or dimension shown, the effect of this invention can be acquired. Therefore, the hole and the contact preventing member 28 in the claims are not limited to the illustrated shape or dimensions.

In addition, this invention is applicable not only to a container ship but to other welded structures. For example, the present invention may be applied to a suitable welded structure that requires the function of stopping the propagation of brittle cracks, such as bulk carriers, offshore structures, or ground buildings.

In the third embodiment, one hole 29 is provided at a position close to the upper deck 4 as shown in FIGS. 9A and 9B, but may be provided at another position, and the weld joint 6 extends. A plurality may be provided at predetermined intervals in the direction. In addition to the hole 18 of the first embodiment, the hole 29 of the third embodiment may be provided.

Thus, this invention is not limited to embodiment mentioned above, Of course, various changes can be added in the range which does not deviate from the summary of this invention.

According to the present invention, there is no welding portion for joining the bonded plate and the bonded plate between the welded joint portion of the bonded plate and the joined plate, so that the brittleness is easily formed at the welded joint in a simple configuration without using an expensive arrester material. Even if a crack occurs, the propagation can be stopped.

Claims (5)

The joining board which two metal plates are joined by welding, and the to-be-joined board joined by welding to this joining board, and the weld seam between the said two metal plates are abutted with the said joining board toward the said to-be-joined board. In the welded structure extending to the vicinity of the bonding position of the plywood, The welded seam is configured such that the welded portion and the to-be-joined plate do not exist in the direction that the welded seam faces the to-be-joined plate, and the welded part and the to-be-joined plate do not exist between the welded seam and the to-be-joined plate. There is a welded structure. In a welding structure comprising a joining plate formed by joining two metal plates by welding, The welding structure which penetrates the welding seam part in the thickness direction of the said joining board so that the welding seam extended between two metal plates may be divided in the middle is provided. The method of claim 1, In the vicinity of the joining position in the joining plate, a hole penetrating in the thickness direction of the joining plate is provided between the welded joint and the joined plate, whereby the welded joint and the joined plate do not come into contact with each other. The weld structure which joins the said joining plate and a to-be-joined plate between a weld seam part and a to-be-joined plate does not exist. The method according to claim 2 or 3, A cover member for blocking the opening of the hole is provided, and the cover member is joined to at least one of the joining member and the member to be joined by fillet welding. The method of claim 1, In the vicinity of the joining position, a contact preventing member is interposed between the welded portion and the plate to be welded, whereby the welded portion and the plate to be joined do not come into contact with the welded portion and the plate to be joined. And a welded part for joining the to-be-joined plate does not exist.

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