WO2018176696A1 - Vertical butt joint welding method for thick plates - Google Patents

Abstract

A vertical butt joint welding method for thick plates, the method comprising: providing welding pieces to be butt-joined (110), creating a groove for welding on the welding pieces to be butt-joined (110), performing CO₂ gas shielded arc welding in the groove to form a weld base layer (130), and performing vertical electrogas welding on the weld base layer (130) to complete remaining groove filling and form a weld covering layer (140). By employing CO₂ gas shielded arc welding to perform initial welding on the groove, a weld base layer difficult to be welded through can be formed at a bottom portion or back surface of the groove, thus ensuring welding quality of the following vertical electrogas welding operation. By combining two welding techniques to weld thick welding pieces to be butt-joined, the present invention lowers operational difficulties, improves welding quality, and effectively reduces a heat input of welding.

Description

Thick plate vertical butt welding method Technical field

The invention relates to the field of welding technology, in particular to a thick plate vertical butt welding method.

Background technique

In the pre-loading and loading stage of the shipbuilding industry, vertical vertical butt welds are generally welded by vertical gas welding. When welding, ceramic gaskets or copper gaskets are attached to the back of the butt joints of the plates. The front and back surfaces are formed to complete the welding of the entire butt weld. This welding method is generally suitable for the butt joint with a thickness of less than 32 mm. When the thickness of the sheet is greater than 32 mm and the board has special requirements for strength or toughness, it must be welded by CO2 semi-automatic or multi-layer automatic welding.

The existing welding methods for thick butt welding have the following defects: 1. For vertical plate welding, if vertical gas welding is used, the requirements for steel plates and filling materials are high. If imported steel plates and filler materials are not used, welding after welding. It is difficult to meet the minimum mechanical performance requirements of the joint, so it will increase the cost of welding, and the operation is difficult, the probability of intermediate arc breaking and welding wear is high, and when the arc is broken or the welding wears, the carbon is needed for the front and back. Planing and repairing greatly reduce the efficiency of welding; 2. During the ship loading stage, the joint gap fluctuates greatly. If the vertical plate is used for vertical gas welding, the welding heat input will also change greatly, which is easy to cause. The mechanical properties of the joints are not up to standard; 3. When semi-automatic or automatic CO2 gas shielded welding, the number of layers of thick plate welding is large, and the welding parameters of each layer are limited to 280A, so the welding efficiency is low; Semi-automatic CO2 gas shielded welding is a manual operation. It requires high skill and responsibility for the welder itself. The number of layers to be welded should be properly arranged, and the angle formed during the process or A welding, the welding quality is relatively poor stability can only be cleared after the defect.

Summary of the invention

The object of the present invention is to provide a thick plate butt welding method which can effectively improve the welding speed and the quality of the weld.

In order to achieve the above object, the present invention adopts the following technical solutions:

Providing a thick plate vertical butt welding method, providing a butt weldment, forming a welding groove on the butt weldment, welding in the groove by using CO2 gas shielded welding to form a weld bottom layer, and adopting vertical gas welding Welding is performed on the weld underlayer to complete the remaining groove fill.

As a preferred embodiment of the thick plate butt welding method, the groove is a single-sided groove, the bottom of the groove is located at the back of the butt weldment, and the top of the groove is located on the front side of the butt weldment.

Preferably, the groove is a single-sided V-shaped groove.

More preferably, the angle of the groove is 30° to 45°.

As a preferred solution for the thick butt welding method, the specific steps are as follows:

S10, pre-processing, opening the butt weldment to the groove, and cleaning the groove;

S20, bottom welding, using CO2 gas shielded welding to weld 2 to 3 layers in the groove to form the weld bottom layer, the thickness of the weld bottom layer is 10-15 mm;

S30. Cover welding, welding the unwelded portion of the groove by vertical gas welding until the entire weld is welded.

As a preferred embodiment of the thick plate butt welding method, a step S11 is further disposed between the step S10 and the step S20, and a lining is attached to the back of the butt weldment and at the bottom of the groove. a pad that blocks the bottom of the groove.

As a preferred embodiment of the thick plate butt welding method, a groove is provided on a side of the groove near the groove, and the groove has a width larger than a width of a gap at the bottom of the groove.

Preferably, the groove is an arc-shaped structure that is recessed toward a side away from the groove.

As a preferred solution of the thick plate vertical butt welding method, after the step S30, the step S40 is further provided, the post-weld treatment is performed, the liner is removed, and the weld bead on both sides of the groove is smoothed until the weld surface and the butt weldment are The surface is flush.

As a preferred embodiment of the thick plate butt welding method, the groove of the butt weldment is a double-sided groove.

Preferably, the double-sided groove comprises a front bevel adjacent to the front surface of the butt welding material and a back surface bevel near the back surface of the butt welding material, the bevel angle of the front bevel is 30° to 45°, The groove angle of the back groove is 40° to 50°.

As a preferred solution for the thick plate vertical butt welding method, the specific steps are as follows:

S100, pre-processing, opening the butt weldment to the groove, and cleaning the groove;

S200, a gasket, a gasket is attached to the bottom of the front groove of the groove, so that the front groove of the groove is not connected to the back groove;

S300, bottom welding, welding in the back groove of the groove by using CO2 gas shielded welding until filling the entire back groove;

S400, cleaning, cleaning the gasket and the welding slag in the front groove;

S500, cover welding, the front bevel is welded by vertical gas welding until the complete front groove is filled.

As a preferred embodiment of the thick plate butt welding method, the liner is a round bar-shaped liner having a diameter slightly larger than the bottom gap of the groove.

As a preferred embodiment of the thick plate butt welding method, the vertical gas welding has a welding current of 400-500 A, a welding voltage of 40-44 V, and a welding speed of 4-8 cm/min.

Preferably, the CO2 gas shielded welding uses a flux-cored wire having a diameter of 1.2 mm, and the model number is E81T1-K2.

The vertical gas welding uses a flux-cored wire having a diameter of 1.6 mm, and the grade is DW-S1LG or SC-EG3.

More preferably, the liner is a copper liner or a ceramic liner.

Further, the bottom gap of the single-sided groove is 5-16 mm.

Further, the bottom gap of the double-sided groove is 5-16 mm.

Further, the back surface of the double-sided groove has a depth of 10-15 mm.

Further, the butt weldment has a thickness of 32-50 mm.

The beneficial effects of the invention are as follows: the thick plate vertical butt welding method of the present invention adopts CO2 gas shielded welding to weld the groove first, and can form a bottom layer in the groove and at the bottom or back of the groove to form a weld seam which is difficult to weld, and further To ensure the subsequent welding quality of vertical gas welding, the combination of two welding methods for welding thicker butt weldments can not only reduce the operation difficulty, improve the welding quality, but also effectively reduce the heat input of welding.

DRAWINGS

The invention will now be described in further detail with reference to the drawings and embodiments.

Fig. 1 is a view showing a state in which a single-side groove is formed in a pair of welded parts according to an embodiment of the present invention.

Fig. 2 is a view showing a state in which a pair of weldments are attached to a gasket according to an embodiment of the present invention.

Fig. 3 is a view showing a state of a pair of welded parts during bottom welding according to an embodiment of the present invention.

Fig. 4 is a view showing a state in which a butt weldment is welded at the time of cover welding according to an embodiment of the present invention.

Fig. 5 is a view showing a state in which a double-sided groove is formed in a butt weldment according to a second embodiment of the present invention.

Fig. 6 is a view showing a state in which a butt weldment is attached to a gasket according to a second embodiment of the present invention.

Fig. 7 is a view showing the state of the butt weldment in the case of bottom welding according to the second embodiment of the present invention.

Fig. 8 is a view showing the state of the butt weldment in the face welding according to the second embodiment of the present invention.

In Figure 1-4:

110, butt weldment; 120, gasket; 121, groove; 130, weld bottom layer; 140, weld cover surface layer; 150, single-sided groove.

In Figure 5-8:

210, butt weldment; 220, gasket; 230, weld bottom layer; 240, weld cover surface layer; 250, double-sided groove; 251, front groove; 252, back groove.

detailed description

The technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only the present invention. Some embodiments, but not all of the embodiments. All other embodiments obtained by a person skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Embodiment 1:

As shown in FIG. 1 to FIG. 4, in the embodiment, a thick plate vertical butt welding method is provided. Specifically, a butt weldment 110 is provided, and a welding groove is formed on the butt weldment 110, and the CO2 gas shielded welding is used. The weld is formed in the groove to form the weld bottom layer 130, and the remaining groove fill is welded on the weld bottom layer 130 by vertical gas welding to form the weld cover surface layer 140. The CO2 gas shielded welding is used to weld the groove first, and the underlayer 130 can be formed in the groove and at the bottom of the groove to form a weld seam which is difficult to weld, thereby ensuring the welding quality of the vertical gas welding, and the two welding methods are thicker. The welding of the butt weldment 110 can not only reduce the operation difficulty, improve the welding quality, but also effectively reduce the heat input of the welding.

The specific steps are as follows:

S10, pre-processing, the butt weldment 110 is opened, wherein the groove is a single-face groove 150, The bottom of the groove is located on the back side of the butt weldment 110, and the top of the groove is located on the front side of the butt weldment 110 to clean the groove;

S20, a gasket 120 is attached to the bottom of the butt weldment 110 and at the bottom of the groove, and the gasket 120 seals the bottom of the groove;

S30, bottom welding, using CO2 gas shielded welding to weld 2 to 3 layers in the groove to form a weld bottom layer 130, the thickness of the weld bottom layer 130 is 10-15 mm;

S40, cover welding, using vertical gas welding on the weld bottom layer 130 to complete the remaining groove filling to form a weld cover surface layer 140;

S50, post-weld treatment, remove the liner 120, and smooth the welds on both sides of the groove until the surface of the weld is flush with the surface of the butt weldment 110.

In this embodiment, the single-face groove 150 is a single-sided V-shaped groove, the angle of the single-face groove 150 is 30° to 45°, and the CO2 gas shielded welding is a flux-cored wire with a diameter of 1.2 mm, and the model is E81T1. -K2, vertical gas welding with a diameter of 1.6mm flux cored wire, grade DW-SILG or SC-EG3, vertical gas welding welding current is 400-500A, welding voltage is 40-44V, welding speed is 4-8cm /min.

Preferably, the liner 120 is a copper liner or a ceramic liner. In the present embodiment, the liner 120 is a ceramic liner.

Further, a groove 121 is disposed on a side of the gasket 120 near the groove, and the width of the groove 121 is greater than the width of the gap at the bottom of the groove. By providing the groove 121 on the gasket 120, the weld overflow space and the heat conduction space can be provided for the welding, effectively preventing the occurrence of bubbles at the weld seam and improving the quality of the weld seam. Preferably, the groove 121 is an arc-shaped structure that is recessed toward a side away from the groove.

Preferably, the bottom gap of the single-sided groove 150 is 5-16 mm, and the thickness of the butt weldment 110 is 32-50 mm.

Embodiment 2:

As shown in FIG. 5 to FIG. 8 , in the embodiment, a thick plate vertical butt welding method is provided, and specifically, a butt weldment 210 is provided, and a welding groove is formed on the butt weldment 210, and the CO2 gas shielded welding is used. The weld is formed in the groove to form the weld bottom layer 230, and the remaining groove fill is welded on the weld bottom layer by vertical gas welding to form the weld cover surface layer 240. The CO2 gas shielded welding is used to weld the groove first, and the underlayer 230 can be formed in the groove and at the bottom of the groove to form a weld seam which is difficult to weld, thereby ensuring the welding quality of the vertical gas welding, and the two welding methods are thicker. The welding of the butt weldment 210 can not only reduce the operation difficulty, improve the welding quality, but also effectively reduce the heat input of the welding.

The specific steps are as follows:

S100, pre-processing, the butt weldment 210 is provided with a groove, the groove is a double-sided groove 250, which has a front groove 251 near the front surface of the butt weldment 210 and a back groove 252 near the back surface of the butt weldment 210, Cleaning the groove;

S200, the adhesive pad 220, the bottom of the front bevel 251 of the groove is attached with a gasket 220, so that the front bevel 251 of the groove and the back bevel 252 are not connected;

S300, bottom welding, welding with CO2 gas shielded welding in the back groove 252 of the groove until filling a complete back groove 252;

S400, cleaning, cleaning the gasket 220 and the welding slag in the front groove 251;

S500, cover welding, welding the front bevel 251 by vertical gas welding until the complete front bevel 251 is filled.

In the present embodiment, the liner 220 is a round bar-shaped liner having a diameter slightly larger than the bottom gap of the groove. The bottom of the groove here refers to the intersection of the front groove 251 and the back groove 252, that is, the bottom of the groove is located inside the butt weldment 210.

In this embodiment, the groove is a double-sided groove 250, and the groove angle of the front groove 251 is 30°. 45°, the groove angle of the back groove 252 is 40°～50°, the CO2 gas shielded welding adopts the flux-cored wire with the diameter of 1.2mm, the model number is E81T1-K2, and the vertical gas welding adopts the core of 1.6mm diameter. The welding wire is graded as DW-SILG or SC-EG3. The welding current of vertical gas welding is 400-500A, the welding voltage is 40-44V, and the welding speed is 4-8cm/min.

Preferably, the liner 220 is a copper liner or a ceramic liner. In the present embodiment, the liner 220 is a copper rod.

More preferably, the bottom gap of the double-sided groove 250 is 5-16 mm, the back groove 252 of the double-sided groove 250 has a depth of 10-15 mm, and the thickness of the butt weldment 210 is 32-50 mm.

Compared with the prior art, the present invention has the following advantages:

1. In the prior art, if vertical gas welding is used for thick plates, the welding operation is difficult, the joints caused by welding stop arc increase, the qualification rate of welding quality decreases, and the weld repair amount is also increased, and the scheme is first adopted at the bottom of the groove. The CO2 gas shielded welding avoids the situation of back-welding, and the welding operation is difficult, and the appearance and internal quality are improved;

2. If the existing thick plate adopts CO2 gas shielded welding, the welding efficiency is low, the welding quality depends on the operator's responsibility and skill, and the instability increases. However, only a small part of the scheme adopts CO2 gas shielded welding, and most of them adopt Vertical gas welding for welding, effectively improving efficiency and reducing the instability of weld quality;

3. For some special steel plates such as E or EH grade steel, or steel plates with higher requirements for low temperature toughness or strength, if vertical plates are directly used for vertical gas welding, the mechanical properties of welded joints are difficult to meet the requirements of the specification. The heat input quantity of the steel plate and the filling material is required to meet the requirements, and the material needs to be imported, which inevitably increases the material cost; and the solution part adopts CO2 gas shielded welding, and some adopts vertical gas electric welding to reduce part of the heat input. It is beneficial to the low temperature toughness of the root and effectively ensures the mechanical properties of the joint.

The technical principles of the present invention have been described above in connection with specific embodiments. These descriptions are just for explanation The principles of the invention are not to be construed as limiting the scope of the invention. Based on the explanation herein, those skilled in the art can devise various other embodiments of the present invention without departing from the scope of the invention.

Claims (10)

A thick plate vertical butt welding method, characterized in that a butt weldment is provided, a welding groove is formed on the butt weldment, and a weld seam is formed by welding in the groove by using CO2 gas shielded welding, and the bottom layer is adopted. Vertical gas welding is performed on the weld underlayer to complete the remaining groove filling. The thick plate vertical butt welding method according to claim 1, wherein the groove is a single-sided groove, the bottom of the groove is located at the back of the butt weldment, and the top of the groove is located at the butt weld. The front of the piece. The thick plate vertical butt welding method according to claim 2, wherein the specific steps are as follows: S10, pre-processing, opening the butt weldment to the groove, and cleaning the groove; S20, bottom welding, using CO2 gas shielded welding to weld 2 to 3 layers in the groove to form the weld bottom layer, the thickness of the weld bottom layer is 10-15 mm; S30. Cover welding, welding the unwelded portion of the groove by vertical gas welding until the entire weld is welded. The slab vertical butt welding method according to claim 3, wherein a step S11 is further provided between the step S10 and the step S20, at the back of the butt weldment and at the groove A liner is attached to the bottom that seals the bottom of the groove. The thick plate vertical butt welding method according to claim 4, wherein a side of the gasket adjacent to the groove is provided with a groove, and a width of the groove is larger than a gap at a bottom of the groove width. The thick plate vertical butt welding method according to claim 3, wherein after the step S30, the step S40 is further provided, the post-weld treatment is performed, the liner is removed, and the weld bead on both sides of the groove is smoothed until the weld surface is It is flush with the surface of the butt weldment. The thick plate vertical butt welding method according to claim 1, wherein the groove of the butt weldment is a double-sided groove. The thick plate vertical butt welding method according to claim 7, wherein the specific steps are as follows: S100, pre-processing, opening the butt weldment to the groove, and cleaning the groove; S200, a gasket, a gasket is attached to the bottom of the front groove of the groove, so that the front groove of the groove is not connected to the back groove; S300, bottom welding, welding in the back groove of the groove by using CO2 gas shielded welding until filling the entire back groove; S400, cleaning, cleaning the gasket and the welding slag in the front groove; S500, cover welding, the front bevel is welded by vertical gas welding until the complete front groove is filled. The thick plate vertical butt welding method according to claim 8, wherein the spacer is a round bar-shaped pad having a diameter slightly larger than a bottom gap of the groove. The thick plate vertical butt welding method according to any one of claims 1 to 9, characterized in that the vertical gas welding has a welding current of 400-500 A, a welding voltage of 40-44 V, and a welding speed of 4-8 cm/ Min.

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