CN111761168A - A method for connecting steel-aluminum composite joints for ships - Google Patents

Abstract

The present invention relates to a method for connecting a steel-aluminum composite joint for ships, comprising: S1. respectively opening openings on the steel wall and the aluminum alloy wall at the corresponding areas where the steel-aluminum composite joint is connected, so as to ensure distance welding at the ends of the openings. The distance between the ends of the parts is greater than the size of the welding feet; S2. Set a certain gap at the connection of the steel-aluminum composite joint, and then weld the steel layer of the steel-aluminum composite joint to the steel wall, the aluminum alloy layer to the aluminum alloy wall, and the gap is not welded. , during welding, arc-starting blocks and arc-extinguishing blocks are respectively set on both sides of the groove; S3. Fillet welding is performed at the opening; S4. Structural adhesive is injected and filled in the gap between the two steel-aluminum composite joints to ensure Seam tightness. In the present invention, the fillet welding is performed at the open end of the bulkhead, which can prevent the steel-aluminum composite joint from cracking due to welding, and can ensure the effective connection between the bulkhead and the steel-aluminum composite joint. The end of the hole enters the weld, which can improve the stress at the end and avoid stress concentration.

Description

A method for connecting steel-aluminum composite joints for ships

technical field

The invention relates to the technical field of ship hull structure design, in particular to a method for butt joint and fillet joint connection of steel-aluminum composite joints for ships.

Background technique

Aluminum alloys are widely used in light and secondary bulkheads of ships due to their low density, high strength, high stiffness and corrosion resistance. The deck material of ships is usually steel. In order to connect the aluminum alloy bulkhead to the deck, steel-aluminum composite joints are usually used. As shown in FIG. 1 , the steel-aluminum composite joint 10 is formed by explosive welding of three materials: a steel layer 11 , an aluminum layer 12 , and an aluminum alloy layer 13 . When connecting, the steel layer 11 of the steel-aluminum composite joint 10 is connected to the steel wall 20 . , the aluminum alloy layer 13 is connected with the aluminum alloy wall 30 . The width and thickness of the steel layer 11 , the aluminum layer 12 and the aluminum alloy layer 13 are selected according to the thickness of the steel wall 20 and the aluminum alloy wall 30 and the height of the welding leg.

Since the purchased steel-aluminum composite joint is a standard part, when its length is less than the bulkhead length, two steel-aluminum composite joints need to be butt welded together. In addition, the upper and lower coamings of the aluminum cabin are usually made of steel, and the aluminum cabin needs to be butted with the steel bulkhead through the steel-aluminum composite joint to form the steel-aluminum composite joint fillet joint.

However, when the steel-aluminum composite joint is connected by butt or fillet, the direct use of conventional welding may lead to interference connection of the joint or damage to the joint boundary layer, and it is easy to crack when exposed to external force. In order to solve the problem of cracking in the steel-aluminum interface of the composite joint, Chinese patent CN104708238 discloses a method for preventing the structural delamination of the steel-aluminum composite material, which adopts the separation distance filling method, that is, the composite joint is directly filled with structural glue for connection. This method can avoid the delamination of the composite joint caused by the welding heat input factor to a certain extent, but when controlling the heat input, the influence of the large temperature change during arc ignition and arc extinction on the control heat input is not considered, nor is the cabin considered. The problem of stress concentration when the wall is connected to the steel-aluminum composite joint.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for connecting steel-aluminum composite joints for ships, which can ensure the effective connection of steel bulkheads and aluminum alloy bulkheads at the steel-aluminum joints. It can also solve the problem of easy cracking at the joint due to improper welding methods.

The technical scheme adopted by the present invention for solving the above-mentioned technical problems is:

A method for connecting steel-aluminum composite joints for ships, which is suitable for butt joint and fillet joint of two steel-aluminum composite joints, comprising the following steps:

S1. Open openings on the steel wall and the aluminum alloy wall, respectively, in the areas corresponding to the connection of the steel-aluminum composite joint to ensure that the distance between the open end and the end of the weldment is greater than the size of the weld foot;

S2. Set a certain gap at the connection of the steel-aluminum composite joint, then weld the steel layer of the steel-aluminum composite joint to the steel wall, and weld the aluminum alloy layer to the aluminum alloy wall. Arc block and arc extinguish block;

S3. Fillet welding is performed at the opening;

S4. Inject and fill the gap between the two steel-aluminum composite joints with structural adhesive to ensure the tightness of the weld.

In the above method, when the steel-aluminum composite joint is butt-connected, the opening is a semi-oval opening, and the chamfering radius is equal to the width of the rectangle.

In the above method, when the steel-aluminum composite joint is connected by fillet connection, the opening is a fan-shaped opening, and the distance between the edge of the hole and the edge of the cut after the opening is chamfered is not less than the value of the fillet gap.

In the above method, when the steel-aluminum composite joint is connected by fillet connection, before S1, the two steel-aluminum composite joints are respectively cut at a 45-degree angle at the corner joint end.

In the above method, the gap between the two steel-aluminum composite joints is set to 4-8 mm.

In the above method, the temperature field formed by the welding procedure specification does not make the temperature of the steel-aluminum interface exceed 300°C.

The beneficial effects of the present invention are:

1. In the method for connecting steel-aluminum composite joints for ships proposed by the present invention, openings are opened on the steel wall and the aluminum alloy wall corresponding to the connection area of the composite joints, and fillet welding is performed at the opening ends of the bulkheads, so as to avoid the steel-aluminum composite joints. While cracking due to welding, the effective connection between the bulkhead and the steel-aluminum composite joint can be ensured, and the fillet welding can prevent water vapor from entering the weld along the end of the opening, and at the same time, it can improve the stress at the end and avoid stress concentration. .

2. When the steel-aluminum composite joint is welded with the steel wall and the aluminum alloy wall respectively, the arc-starting block and the arc-extinguishing block are set on both sides of the groove, which can reduce welding defects and stably control the welding heat input.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

Fig. 1 is the schematic diagram of steel-aluminum composite joint;

2 is a schematic diagram of the connection of the butt joint of the steel-aluminum composite joint in the first embodiment of the present invention;

Fig. 3 is the schematic diagram of the arc striking and arc extinguishing block according to the first embodiment of the present invention;

Fig. 4 is the connection schematic diagram of the fillet joint of the steel-aluminum composite joint in the second embodiment of the present invention;

Fig. 5 is the schematic diagram of the arc striking and arc extinguishing block of the second embodiment of the present invention;

In the picture: 10, steel-aluminum composite joint; 11, steel layer; 12, aluminum layer; 13, aluminum alloy layer; 20, steel wall; 30, aluminum alloy wall; 40, arc striking block; 50, arc extinguishing block .

Detailed ways

In order to have a clearer understanding of the technical features, objects and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

First embodiment:

As shown in Figure 2, the method for butt connection of steel-aluminum composite joints includes the following steps:

Step 1. A semi-oval opening with a chamfering radius of R5mm of 15mm×5mm is opened on the steel wall 20 and the aluminum alloy wall 30 respectively. The length of the opening can be adjusted according to the size of the welding leg and the butt gap, but it should be ensured that the distance between the open end and the end wall of the weldment is greater than the size of the welding leg. In this way, it can ensure that the fillet welding is completed at the end of the bulkhead without damaging the boundary layer of the steel-aluminum composite joint, and avoiding the delamination of the boundary layer due to the influence of welding.

Step 2. Set a 6mm gap at the butt joint of the steel-aluminum composite joint 10, and then weld the steel layer 11 of the steel-aluminum composite joint 10 to the steel wall 20, the aluminum alloy layer 13 to the aluminum alloy wall 30, and the gap is not welded. As shown in FIG. 3 , small arc-starting blocks 40 and small arc-extinguishing blocks 50 are respectively provided on both sides of the groove during welding. The temperature field formed by the welding procedure specification should not cause the temperature of the steel-aluminum interface to exceed 300°C, reduce welding defects and stably control the effect of welding heat input, and avoid damaging the boundary layer of the steel-aluminum composite joint 10, thereby causing delamination and cracking .

Step 3. Fillet welding is performed at the semi-oval opening. Fillet welding is used to prevent water vapor from entering the weld along the end of the opening, and at the same time, it can improve the stress of the end and avoid stress concentration.

Step 4. Inject and fill the structural adhesive in the gap between the two steel-aluminum composite joints 10 to ensure the sealing of the weld.

The butt connection method of the steel-aluminum composite joint 10 in this embodiment is applicable to: the steel wall 20 is the steel sill of the light secondary bulkhead of the ship, and the aluminum alloy wall 30 is the light and secondary bulkhead of the ship.

Second embodiment:

As shown in FIG. 4 , the steel-aluminum composite joint 10 is connected by fillet connection, which includes the following steps:

Step 1. Cut the two steel-aluminum composite joints 10 at an angle of 45 degrees at the corner joint ends respectively.

Step 2, opening fan-shaped openings with a chamfering radius R10mm on the steel wall 20 and the aluminum alloy wall 30 respectively. The radius of the fan-shaped opening can be adjusted according to the size of the welding leg and the butt gap, but it should be ensured that the distance between the open end and the end wall of the weldment is greater than the size of the welding leg.

Step 3. Set a 6mm gap at the corner connection of the steel-aluminum composite joint 10, and then weld the steel layer 11 of the steel-aluminum composite joint 10 to the steel wall 20, the aluminum alloy layer 13 to the aluminum alloy wall 30, and the gap is not welded. During welding, arc striking blocks 40 and arc extinguishing blocks 30 are respectively provided on both sides of the groove. The temperature field formed by the welding procedure specification should not cause the temperature of the steel-aluminum interface to exceed 300°C.

Step 4. Fillet welding is performed at the fan-shaped opening.

Step 5. Inject and fill the structural adhesive in the gap between the two joints to ensure the sealing of the weld.

The steel-aluminum composite joint 10 corner connection method of this embodiment is applicable to: the upper left steel wall 20 is the steel sill of the light secondary bulkhead, the aluminum alloy wall 30 at the lower end is the light and secondary bulkhead of the ship, and the right side is the light and secondary bulkhead of the ship. The steel wall 20 is the light and secondary bulkhead of the ship.

The embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the inspiration of the present invention, without departing from the scope of protection of the present invention and the claims, many forms can be made, which all belong to the protection of the present invention.

Claims (6)

1. A method for connecting steel-aluminum composite joints for ships, characterized in that the connection method is suitable for butt joints and fillet joints of two steel-aluminum composite joints, comprising the following steps: S1. Open openings on the steel wall and the aluminum alloy wall, respectively, in the areas corresponding to the connection of the steel-aluminum composite joint to ensure that the distance between the open end and the end of the weldment is greater than the size of the weld foot; S2. Set a certain gap at the connection of the steel-aluminum composite joint, then weld the steel layer of the steel-aluminum composite joint to the steel wall, and weld the aluminum alloy layer to the aluminum alloy wall. Arc block and arc extinguish block; S3. Fillet welding is performed at the opening; S4. Inject and fill the gap between the two steel-aluminum composite joints with structural adhesive to ensure the tightness of the weld. 2 . The method for connecting steel-aluminum composite joints for ships according to claim 1 , wherein when the steel-aluminum composite joint is butt-connected, the opening is a semi-oval opening, and the chamfering radius is equal to the width of the rectangle. 3 . . 3 . The method for connecting a steel-aluminum composite joint for ships according to claim 1 , wherein when the steel-aluminum composite joint is connected by fillet connection, the opening is a fan-shaped opening, and the hole is chamfered after the opening is chamfered. The edge distance is not less than the fillet gap value. 4 . The method for connecting steel-aluminum composite joints for ships according to claim 1 , wherein when the steel-aluminum composite joints are connected by fillet connection, before S1, two steel-aluminum composite joints are first connected to the fillet ends. 5 . Parts are cut at a 45-degree angle. 5 . The method for connecting steel-aluminum composite joints for ships according to claim 1 , wherein the gap between the two steel-aluminum composite joints is set to 4-8 mm. 6 . 6 . The method for connecting steel-aluminum composite joints for ships according to claim 1 , wherein the temperature field formed by the welding process specification does not make the temperature of the steel-aluminum interface exceed 300° C. 7 .

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