CN115958269A - Welding method - Google Patents

Abstract

The invention relates to the field of welding and discloses a welding method. The welding method adopts a ceramic liner to carry out single-side vertical welding on the joint of a workpiece to form a welding seam, a V-shaped groove or a U-shaped groove is arranged at the joint, when the vertical welding is carried out, a welding wire swings around the joint along a zigzag gradually upward route, and when the welding wire swings left and right around the joint, the time of the welding wire staying in the middle area of the joint is reduced, and the time of the welding wire staying in the left and right areas of the joint is increased; and when the welding seam is welded, the welding wire moves towards the outer side of the groove, the heat of the molten pool is controlled together, and the phenomenon that the root position of the welding seam is overhigh in heat to cause welding beading or welding penetration is reduced or avoided.

Description

Welding method

Technical Field

The invention relates to the field of welding, in particular to a welding method.

Background

The semi-automatic carbon dioxide gas protection ceramic liner single-side welding is an efficient welding method, has the advantages of high deposition efficiency, relatively low requirement on assembly gap precision, no back gouging, small welding deformation and the like, and is widely applied to the industries of shipbuilding, steel structure manufacturing and the like. In the hull construction, single-side welding of the ceramic liner is commonly carried out at three welding positions, namely flat welding, transverse welding and vertical welding, a gap of 4-8mm is reserved before welding in assembly, the ceramic liner is attached to the back side of a welding seam and welded from the front side, the back side can be formed at one time, welding toes of the welding seam on the back side are neat, and the height, the width and the width are uniform. When welding is carried out at the 3G vertical welding position, the welding difficulty is higher than that of horizontal welding and transverse welding due to the fact that molten iron in a molten pool drops due to gravity. In actual production, the welding is convenient when the assembly clearance is 4-8 mm; however, due to reasons such as construction accuracy, an assembly gap of 10mm or more, even 16mm, may occur, and as the gap of the workpiece, i.e., the joint, increases, the difficulty of welding increases in multiples. Due to the material of the ceramic liner, broken arc welding cannot be adopted when large gaps are welded, so that the problems of welding penetration, welding beading, top penetration of the ceramic liner by a welding wire and the like in the welding process are caused, and the welding quality is seriously influenced.

Disclosure of Invention

The invention aims to overcome the defect of poor welding quality when ceramic gaskets are adopted for large-gap welding in the prior art, and provides a welding method.

The invention solves the technical problems through the following technical scheme:

a welding method is characterized in that a ceramic liner is adopted to carry out single-side vertical welding on a joint of a workpiece to form a welding seam, a V-shaped groove or a U-shaped groove is formed in the joint, the width of the joint is larger than or equal to 10mm, a welding wire swings around the joint along a zigzag gradually upward route when the vertical welding is carried out, the time of the welding wire staying in the middle area of the joint is reduced when the welding wire swings left and right around the joint, the time of the welding wire staying in the left area and the right area of the joint is increased, and the welding wire moves towards the outer side of the groove when the joint is welded so as to reduce or avoid the phenomena of welding beading and welding penetration.

In the technical scheme, the width of the joint is more than or equal to 10mm, the welding is large-gap welding, the largest difference of the small-gap ceramic liner welding with the width of the joint less than 10mm is that the position of a welding wire in a molten pool (the position corresponding to the thickness direction of a workpiece) is different, and the welding wire swings near the root of the welding wire in order to ensure that the root of the welding wire can be completely melted through during the small-gap liner welding; during large-gap welding, the molten iron cannot be immediately solidified to form an effective backing for a welding molten pool due to too high heat of the molten pool in the vicinity of the root of a welding seam, and the phenomena of penetration and welding flash can be immediately caused; therefore, in the technical scheme, the welding wire moves a certain distance towards the outer side of the groove to reduce or avoid the phenomenon of welding beading or welding through caused by overhigh heat of a molten pool; and a zigzag gradually upward route is adopted. The welding wire upwards swings around the seam gradually, and the phenomenon that the welding seam quality formed is poor due to the backing is avoided. The welding wire swings along a zigzag gradually upward route, and when the welding wire swings left and right around a joint, the stay time of the welding wire in the middle area of the joint is shortened, and the stay time of the welding wire in the left and right areas of the joint is prolonged, so that the heat of a welding pool is controlled, and the phenomenon that welding beading or welding penetration is caused by overhigh heat at the root position of a welding seam is reduced or avoided. When the width of the seam is large, the welding speed is slow, and the back surface cannot be unfused, so that the back surface of the welding seam cannot be unfused due to the fact that the time of staying in the middle area of the seam is properly reduced.

The welding method is characterized in that the reduction amount of the stay time of the welding wire in the middle area of the joint, the increase amount of the stay time of the welding wire in the left and right areas of the joint and the moving distance of the welding wire to the outer side of the groove are obtained by practical operation, and the welding method is based on the reduction or complete avoidance of welding beading and welding through phenomena. When the welding wire swings left and right around the joint, the time of staying in the middle area of the joint is reduced, the time of staying the welding wire in the middle area of the welding joint is reduced, and the welding wire does not need to be positioned in the middle area of the joint; the left and right regions are the same and will not be described again.

Preferably, the residence time of the welding wire in the seam area is gradually reduced as the height of the weld seam formed increases as the welding wire moves upwardly around the seam.

In the technical scheme, the height of the welding seam is gradually increased in the process that the welding wire gradually moves upwards in the vertical direction, the heat of a molten pool is controlled by reducing the stay time of the welding wire in a seam area, and the phenomenon that welding beading or welding penetration is caused by overhigh heat at the root position of the welding seam is further reduced or avoided.

Preferably, the reduction of the stay time of the welding wire in the middle area of the seam, the increase of the stay time of the welding wire in the left and right areas of the seam, the reduction of the stay time of the welding wire in the seam area along with the increase of the height of the formed welding seam and the distance of the welding wire moving to the outer side of the groove are adjusted according to the size of the seam so as to reduce or avoid the phenomena of welding flash and welding penetration.

In the technical scheme, different seam sizes have different characteristics during welding, when large-gap welding with different sizes is carried out, the operation during welding is adjusted according to the sizes of the seams, a better scheme is obtained according to practical operation, and the welding quality is improved on the basis of reducing or completely avoiding welding beading and welding through phenomena.

Preferably, before welding the joint, the arc striking plate and the arc quenching plate are fixed on the workpiece in a spot welding mode, the arc striking plate is located at the lower end of the joint, and the arc quenching plate is located at the upper end of the joint.

In the technical scheme, the welding seam formed by spot welding is small, so that the arc striking plate and the arc extinguishing plate can be conveniently detached from the workpiece after welding is finished. The arc striking plate is arranged at the lower end of the joint, and the arc extinguishing plate is arranged at the upper end of the joint, so that the welding defects of incomplete fusion or cracks and the like at the upper end and the lower end of the joint are avoided when the joint is welded.

Preferably, the middle portion of the gasket has an alignment line, the gasket is placed on the back of the seam before welding, and the position of the gasket relative to the seam is adjusted so that the alignment line of the gasket corresponds to the center of the seam.

In the technical scheme, the front side of the seam is the side of the welding gun and the welding wire extending to the seam, and the back side of the seam is the side far away from the welding gun. Adjusting the liner to enable the alignment line of the liner to correspond to the center of the seam, so that the formed seam has good quality; meanwhile, the stay time of the welding wire in different areas of the joint is convenient to control according to the alignment lines.

Preferably, the width of the seam is less than or equal to 15mm and less than or equal to 19mm.

Preferably, when welding, the welding wire is inclined downwards, the included angle between the welding wire with the horizontal plane is more than or equal to 20 degrees and less than or equal to 30 degrees, and the dry elongation of the welding wire with the length of 12mm is more than or equal to 15mm.

Preferably, the welding current is less than or equal to 150A and less than or equal to 160A, and the arc voltage is less than or equal to 23V and less than or equal to 24V.

Preferably, the angle of the one-sided bevel of the joint of the workpiece is 25 °.

Preferably, the method is used for welding ships and adopts carbon dioxide gas shielded welding.

In the technical scheme, when the ship is welded, the welding amount is large, carbon dioxide gas is adopted for welding protection, and the cost is low. In other welding scenarios, the mixed gas shielded welding can also be adopted.

The positive progress effects of the invention are as follows:

when the welding wire swings left and right around the joint, the time of staying in the middle area of the joint is shortened, the time of staying in the left area and the right area of the joint is prolonged, and when the joint is welded, the welding wire moves towards the outer side of the groove to control the heat of a molten pool, and the phenomenon that welding beading or welding penetration is caused due to the fact that the heat of the root position of the welding line is too high is reduced or avoided.

Drawings

Fig. 1 is a schematic perspective view of a workpiece.

FIG. 2 is a schematic front structural view of a workpiece, an arc striking plate and an arc extinguishing plate.

FIG. 3 is a front view of the workpiece, the arc striking plate, the arc quenching plate and the gasket.

Description of reference numerals:

workpiece 1

Joint 2

Groove 3

Arc striking plate 4

Arc extinguishing plate 5

Liner 6

Alignment line 7

Width direction W

Height direction H

Width W1 of seam 2

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.

Fig. 1-3 are schematic structural diagrams provided in this embodiment.

As shown in fig. 1, a joint 2 is formed between two workpieces 1, the width W1 of the joint 2 is 16mm, the single bevel 3 has an angle of 25 °, the workpiece 1 is made of a marine steel plate DH36, the plate thickness is 16mm, and the welding position is 3G vertical welding. Adopting carbon dioxide gas shielded welding, adopting direct current reverse connection for a welding machine, wherein the flow of the carbon dioxide gas is between 15 and 20L/min; flux-cored wire brand GFL-71; the liner 6 is made of ceramic and is marked with a mark TC-A3; the welding current is between 150 and 160A, the arc voltage is between 23 and 24V, and the current and the voltage are matched properly; the welding gun is inclined downwards by an angle, so that the welding wire is inclined downwards, the included angle between the welding wire and the horizontal plane is 20-30 degrees, and the dry elongation of the welding wire is 12-15 mm.

As shown in fig. 2, before welding, the arc striking plate 4 and the arc quenching plate 5 are installed at two ends of the workpiece 1, and the arc striking plate 4 and the arc quenching plate 5 are fixed on the workpiece 1 by spot welding, so that the arc striking plate 4 is located at the lower end of the joint 2, and the arc quenching plate 5 is located at the upper end of the joint 2. The arrow pointing in the direction of height H in fig. 2 is from low to high.

As shown in figure 3, before welding, the red alignment line 7 in the middle of the gasket 6 is corresponding to the center of the joint 2, oil stain, rust and the like on the surface of the workpiece 1 are cleaned, the aluminum foil adhesive paper of the gasket 6 is tightly attached to a test board, and the gasket 6 is prevented from falling off due to high-temperature heating in the welding process. The red alignment lines 7 in the middle of the pad 6 are actually solid lines, and the alignment lines 7 are shown as dashed lines in fig. 3 for ease of illustration.

Because the clearance of the bottom layer is large, the welding time is long, and various personal protection works need to be done. During welding, a zigzag upward gesture is adopted, the welding gun is swung left and right, the left side and the right side of the seam 2 are slightly stopped, and the retention time of the middle area of the seam 2 is short. The width of the joint 2 in the embodiment is large, the largest difference between the welding of the small-gap ceramic liner 6 and the welding of the small-gap ceramic liner is that the welding wire is positioned in a molten pool, namely the welding wire is positioned corresponding to the thickness direction of the workpiece 1, and the welding wire swings near the root of the welding line in order to ensure that the root of the welding line can be completely melted through when the small-gap liner 6 is welded; during large-gap welding, the molten iron cannot be immediately solidified to form an effective backing for a welding molten pool due to too high heat of the molten pool in the vicinity of the root of a welding seam, and the phenomena of penetration and welding flash can be immediately caused. When the welding method improved by the embodiment is adopted for welding, the welding wire is moved to the outer side of the groove 3 by a distance of a plurality of millimeters, a left-right swing gesture is kept, the heat balance of the whole molten pool needs to be focused during welding, and no welding beading is generated. Because the back surface has large clearance and slower welding speed and can not generate unfused welding, the situation of back surface welding seam fusion basically does not need to be considered during welding. The reduction of the stay time of the welding wire in the middle area of the joint 2 and the increase of the stay time of the welding wire in the left and right areas of the joint 2 are compared with the moving distance of the welding wire to the outer side of the groove 3 in the small-gap ceramic liner 6, and a better scheme is obtained through practical operation, so that the phenomena of welding beading and welding penetration are reduced or completely avoided.

Preferably, the dwell time of the welding wire in the region of the seam 2 is gradually reduced as the height of the weld seam formed increases when welding takes place. In the process that the welding wire gradually moves upwards in the vertical direction, the height of the formed welding seam is gradually increased, the heat of a molten pool is controlled by reducing the stay time of the welding wire in the area of the seam 2, and the phenomenon that the root position of the welding seam is overhigh in heat to cause welding beading or welding penetration is further reduced or avoided.

By adopting the welding method provided by the embodiment, the quality of the welded seam is reliable, the front side of the welded seam is smooth, the back side of the welded seam is uniform, and the problem that the gap of the welded seam exceeds the standard due to the construction and assembly precision error of the ship body is solved.

In other embodiments, the width W1 of the seam 2 may be sized differently than in the present embodiment. The welding method provided by the embodiment can be used for the condition that the width of the seam 2 is more than or equal to 10mm and can also be used for the condition of 8-10 mm. Preferably, this applies to the case where the width of the seam 2 is between 15 and 19mm.

In other embodiments, the thickness of the workpiece 1 and the angle of the bevel 3 may be different from those of the present embodiment. In other embodiments, the welding method of the present embodiment may be used to weld the U-groove 3. The seam 2 has different characteristics when having different sizes and also has different characteristics when welding, when carrying out the seam 2 welding of different sizes, operation when properly adjusting the welding according to the size of seam 2 to obtain better scheme according to the practice operation, with reduce or avoid welding beading and weld and wear the phenomenon completely as the standard, in order to improve welding quality. Specifically, the stay time of the welding wire in the middle area of the seam 2, the stay time of the welding wire in the left and right areas of the seam 2, the stay time of the welding wire in the area of the seam 2 along with the increase of the height of the formed welding seam, the moving distance of the welding wire to the outer side of the groove 3 and the like can be adjusted. When the joints 2 with different sizes are welded, the carbon dioxide gas flow, the flux-cored wire mark, the liner 6 mark, the welding current, the arc voltage, the included angle between the welding wire and the horizontal plane, the dry elongation of the welding wire and the like can be adjusted according to actual conditions, so that the phenomena of welding beading and welding penetration are reduced or completely avoided, and the welding quality is improved.

In the present embodiment, the arc striking plate 4 and the arc quenching plate 5 are used to avoid welding defects such as non-fusion or cracks at the upper and lower ends of the joint 2 when the joint 2 is welded. In other embodiments, this may not be used.

In the embodiment, a welding method of the ship workpiece 1 is provided, when the ship is welded, the welding amount is large, carbon dioxide gas is used for welding protection, and the cost is low. In other welding scenarios, the mixed gas shielded welding can also be adopted.

Values within a range are meant to include end values, such as welding currents between 150 and 160A, including 150A and 160A.

The left and right in the present invention refer to the orientation in the width direction W (see fig. 2) which is approximately parallel to the horizontal direction; upper end, lower end, upward, etc., refer to an orientation in a height direction H (see fig. 2) that is generally parallel to the vertical direction.

While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and that the scope of the invention is defined by the appended claims. Various changes or modifications to these embodiments may be made by those skilled in the art without departing from the principle and spirit of this invention, and these changes and modifications are within the scope of this invention.

Claims (10)

1. A welding method is characterized in that a ceramic liner is adopted to carry out single-side vertical welding on a joint of a workpiece to form a welding seam, a V-shaped groove or a U-shaped groove is formed in the joint, the width of the joint is larger than or equal to 10mm, when the vertical welding is carried out, a welding wire swings around the joint along a zigzag gradually upward route, when the welding wire swings left and right around the joint, the time of the welding wire staying in the middle area of the joint is shortened, the time of the welding wire staying in the left and right side areas of the joint is increased, and when the joint is welded, the welding wire moves towards the outer side of the groove to reduce or avoid the phenomena of welding beading and welding through.

2. A welding method as claimed in claim 1, wherein the dwell time of the welding wire in the region of the joint is gradually reduced as the height of the weld bead formed increases as the welding wire moves upwardly around the joint.

3. The welding method according to claim 2, wherein the reduction of the stay time of the welding wire in the middle area of the joint, the increase of the stay time of the welding wire in the left and right areas of the joint, the reduction of the stay time of the welding wire in the joint area with the increase of the height of the formed weld, and the moving distance of the welding wire to the outside of the groove are adjusted according to the size of the joint to reduce or avoid the flash and penetration phenomena.

4. A welding method according to claim 1, characterized in that the arc starting plate and the arc quenching plate are fixed to the workpiece by spot welding before the welding of the joint is carried out, such that the arc starting plate is located at the lower end of the joint and the arc quenching plate is located at the upper end of the joint.

5. A welding method according to claim 1, characterised in that the middle part of the pad has an alignment line, that the pad is placed on the back side of the joint before welding and that the position of the pad relative to the joint is adjusted so that the alignment line of the pad corresponds to the centre of the joint.

6. Welding method according to claim 1, characterised in that the width of the joint is 15mm ≦ 19mm.

7. The welding method of claim 1, wherein the welding wire is tilted downward while welding, and an angle between the welding wire of 20 ° or more and the horizontal plane is 30 ° or less, and a dry elongation of the welding wire of 12mm or more and 15mm or less.

8. A welding method as defined in claim 1, characterized in that the welding current is 150A-160A, 23V-24V.

9. The welding method of claim 1, wherein the angle of the single-sided bevel of the joint of the workpiece is 25 °.

10. A welding method according to claim 1, characterized in that it is used for welding of ships and carbon dioxide arc welding is used.

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