阅读说明：本技术 一种t型接头坡口焊接方法 (T-shaped joint groove welding method ) 是由 李晓辉 武永亮 王飞 易冉 邹长青 陈良江 刘坚 王彦元 赵元鹏 许金顺 龙英 于 2020-07-10 设计创作，主要内容包括：本发明公开了一种T型接头坡口焊接方法,T型接头包括第一工件和至少一个第二工件,第一工件与第二工件的待连接部位为焊接位置,焊接位置上设置有单V坡口；第二工件的待焊接面构成单V坡口的坡口面,各个第二工件的坡口面的角度完全相同、部分相同或完全不同；焊接方法具体包括打底层焊接、填充层焊接和盖面层焊接；填充层焊接采用多层多道焊接；控制多层多道焊接时,每层焊缝中的每道焊缝的厚度均匀一致,以使焊缝表面与未焊接的坡口面的角度不小于90°,使得焊缝与腹板坡口连接处充分熔合,从而解决了现有技术中焊缝与腹板坡口面的未熔合缺陷。(The invention discloses a T-shaped joint groove welding method, wherein a T-shaped joint comprises a first workpiece and at least one second workpiece, the parts to be connected of the first workpiece and the second workpiece are welding positions, and a single V groove is arranged on the welding positions; the surfaces to be welded of the second workpieces form the bevel surfaces of the single V-shaped groove, and the angles of the bevel surfaces of the second workpieces are completely the same, partially the same or completely different; the welding method specifically comprises the steps of welding a bottom layer, welding a filling layer and welding a cover layer; the filling layer welding adopts multilayer multi-pass welding; when multi-layer and multi-pass welding is controlled, the thickness of each welding seam in each layer of welding seam is uniform, so that the angle between the surface of the welding seam and the bevel face which is not welded is not less than 90 degrees, the joint of the welding seam and the web groove is fully fused, and the defect that the welding seam and the web bevel face are not fused in the prior art is overcome.)

1. A T-shaped joint groove welding method is characterized in that a T-shaped joint comprises a first workpiece and at least one second workpiece, the parts to be connected of the first workpiece and the second workpiece are welding positions, and a single V groove is arranged on each welding position; the surface to be welded of the second workpiece forms a bevel surface of the single V groove; when the number of the second workpieces is more than two, the angles of the bevel face of each second workpiece are completely the same, partially the same or completely different;

The T-shaped joint groove welding method specifically comprises the following steps: welding a priming coat; welding the filling layer; welding the cover surface layer; the filling layer is welded by adopting multilayer and multi-pass welding; when multi-layer and multi-pass welding is controlled, the thickness of each welding seam in each layer of welding seam is consistent, so that the angle between the surface of the welding seam and the surface of the bevel face which is not welded is not less than 90 degrees.

2. The groove welding method for a T-joint according to claim 1, characterized in that: the bottom layer is welded by a left welding method or a right welding method, and the size of a welding leg is 5-6 mm; in the welding process, the included angle between the welding gun and the first workpiece is 15-35 degrees, and the forward inclination angle between the welding gun and the welding direction is 70-110 degrees; the electric arc blowing force is utilized to delay the propulsion of the liquid metal in the molten pool.

3. The groove welding method for a T-joint according to claim 1, characterized in that: the filling layer welding adopts a left-hand welding method, and after the filling layer welding is completed, the welding bead reserved depth is 1-3 mm and is used for performing the cover surface layer welding.

4. The groove welding method for a T-joint according to claim 3, characterized in that: the multilayer multi-pass weld comprising: and the ith layer adopts i welding, i belongs to [2, N ], and N is the total number of layers of the multilayer and multi-pass welding.

5. The groove welding method for a T-joint according to any one of claims 1 to 4, characterized in that: a first layer weld of the filler layer welds, comprising:

the size of the welding leg is 7-8 mm; in the welding process, the included angle between the welding gun and the first workpiece is 20-40 degrees, and the backward inclination angle between the welding gun and the welding line direction is 70-90 degrees;

and (3) adopting a circular strip conveying method, a crescent strip conveying method, a zigzag strip conveying method or a triangular strip conveying method, when the welding wire is conveyed to the included angle between the upper side of the welding bead and the groove of the second workpiece and stays for 0.5-1 s, and then is obliquely pulled downwards to the position, connected with the first workpiece, of the lower side of the molten pool and is far from the front end 1/4 of the molten pool, so as to ensure that the two sides of the welding bead are fully fused with the base metal.

6. The groove welding method for a T-joint according to claim 5, characterized in that: a second layer weld of the filler layer weld comprising:

first welding: the size of the welding leg is 3-6 mm, and the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun and the first workpiece is 15-35 degrees, the back inclination angle between the welding gun and the welding line direction is 60-85 degrees, and a linear reciprocating strip conveying method is adopted;

and (3) welding the rest channels: the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun and the bevel face is 40-70 degrees, the back inclination angle between the welding gun and the welding line direction is 60-70 degrees, and a small crescent strip conveying method or a small inclined circle strip conveying method is adopted; when the welding wire is conveyed to the lower side of the welding bead, the welding wire is pressed back to the position with the width of the upper welding seam of 1/2-2/3;

And in the welding process of the second layer, the angle between the surface of the welding seam and the non-welded bevel face is always ensured to be not less than 90 degrees until the second layer is welded.

7. The groove welding method for a T-joint according to claim 6, characterized in that: the third and remaining layer welds of the filler weld, including:

first welding: the size of the welding leg is 3-6 mm, and the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun and the first workpiece is 15-35 degrees, the back inclination angle between the welding gun and the welding line direction is 60-85 degrees, and a linear reciprocating strip conveying method is adopted;

welding a middle channel: adopting a left welding method, wherein the thickness of a welding seam is 3-6 mm, the lower included angle between a welding gun and the surface of the welding seam is 75-95 degrees, the back inclination angle between the welding gun and the welding seam direction is 60-70 degrees, adopting a linear reciprocating strip conveying method or a small inclined circle strip conveying method, and when a welding wire conveys a strip to the lower side of the welding seam, pressing back the upper welding seam at the position of 1/2-2/3;

and (3) final welding: the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun and the bevel face is 40-70 degrees, the back inclination angle between the welding gun and the welding line direction is 60-70 degrees, and a small crescent strip conveying method or a small inclined circle strip conveying method is adopted; when the welding wire is conveyed to the lower side of the welding bead, the welding wire is pressed back to the position with the width of the upper welding seam of 1/2-2/3;

And in the welding process of the third layer and the rest layers, the angle between the surface of the welding seam and the bevel face which is not welded is always ensured to be not less than 90 degrees until the filling layer is welded.

8. The groove welding method for a T-joint according to any one of claims 1 to 4 and 6 to 7, wherein: the facing layer welding includes:

first welding: adopting a left welding method, wherein in the welding process, the included angle between a welding gun and the first workpiece is 25-55 degrees, the back inclination angle between the welding gun and the welding seam direction is 60-90 degrees, and fusing 1-2 mm of the first workpiece edge by adopting a straight-line reciprocating strip conveying method;

welding a middle channel: adopting a left welding method, wherein the thickness of a welding seam is 3-6 mm, the lower included angle between a welding gun and the surface of the welding seam is 75-95 degrees, the back inclination angle between the welding gun and the welding seam direction is 60-70 degrees, adopting a linear reciprocating strip conveying method or a small inclined circle strip conveying method, and when a welding wire conveys a strip to the lower side of the welding seam, pressing back the upper welding seam at the position of 1/2-2/3;

and (3) final welding: in the welding process, the lower included angle between a welding gun and the surface of the welding seam is 65-95 degrees, the backward inclination angle between the welding gun and the welding seam is 65-85 degrees, a linear reciprocating strip conveying method is adopted, the center of a fusion line on the upper side of the welding seam and the center of a fusion line of the welding seam is used as a center for conveying the strip, and the welding seam and the edge of the groove of the second workpiece are fused by 0.5-1 mm.

9. The groove welding method for a T-joint according to any one of claims 1 to 4 and 6 to 7, wherein: before the welding of the priming layer, the T-shaped joint groove welding method further comprises tack welding, wherein the tack welding distance is 500-600 mm.

10. The groove welding method for a T-joint according to claim 9, characterized in that: the welding seam of the spot welding is divided into two layers: the length of a first layer of welding seams is 80-100 mm, and the size of a welding leg is 5-6 mm; the second layer of welding seam is located the centre of first layer welding seam, and welding seam length is 40 ~ 60mm, and the leg size is 7 ~ 8mm, and the welding seam joint of twice welding seam staggers more than 20mm to make things convenient for follow-up welding.

Technical Field

The application belongs to the technical field of welding, and particularly relates to a T-shaped joint groove welding method.

Background

T-joints are one of the most common forms of welded joints, and have found numerous applications in railway freight car underframe, such as box beam welding, which is the primary load bearing member of railway cars.

The T-shaped joint groove weld joint requires full penetration and ultrasonic nondestructive detection, and in the actual production process, for a plate with thick plate, a large amount of unfused parts are often generated at the joint of the weld joint and the workpiece groove surface, and the plate is thick, so that the repair is extremely difficult, and the welding quality cannot meet the technical requirements of products.

Disclosure of Invention

In order to solve the technical problems, the invention provides a T-shaped joint groove welding method which controls the thickness of each welding seam in each layer of welding seam to be uniform and consistent, ensures that the angle between the surface of the welding seam and a web is not less than 90 degrees, ensures that the joint of the welding seam and the groove is fully fused, and solves the problem of incomplete fusion between the welding seam and the bevel face of a workpiece in the prior art.

The technical scheme adopted for achieving the purpose of the invention is that the T-shaped joint groove welding method comprises a first workpiece and at least one second workpiece, the parts to be connected of the first workpiece and the second workpiece are welding positions, and a single V groove is arranged on the welding positions; the surfaces to be welded of the second workpieces form the bevel surfaces of the single V-groove, and when the number of the second workpieces is more than two, the angles of the bevel surfaces of the second workpieces are completely the same, partially the same or completely different;

The T-shaped joint groove welding method specifically comprises the following steps: welding a priming coat; welding the filling layer; welding the cover surface layer; the filling layer is welded by adopting multilayer and multi-pass welding; when multi-layer and multi-pass welding is controlled, the thickness of each welding seam in each layer of welding seam is consistent, so that the angle between the surface of the welding seam and the surface of the bevel face which is not welded is not less than 90 degrees.

Furthermore, a left welding method or a right welding method is adopted for welding the bottom layer, and the size of a welding leg is 5-6 mm; in the welding process, the included angle between the welding gun and the first workpiece is 15-35 degrees, and the forward inclination angle between the welding gun and the welding direction is 70-110 degrees; the electric arc blowing force is utilized to delay the propulsion of the liquid metal in the molten pool.

And furthermore, a left welding method is adopted for welding the filling layer, and after the filling layer is welded, the reserved depth of the welding bead is 1-3 mm, and the welding bead is used for welding the cover layer.

Further, the multi-layer, multi-pass welding comprises: and the ith layer adopts i welding, i belongs to [2, N ], and N is the total number of layers of the multilayer and multi-pass welding.

Further, a first layer weld of the filler layer welds, comprising:

the size of the welding leg is 7-8 mm; in the welding process, the included angle between the welding gun and the first workpiece is 20-40 degrees, and the backward inclination angle between the welding gun and the welding line direction is 70-90 degrees;

And (3) adopting a circular strip conveying method, a crescent strip conveying method, a zigzag strip conveying method or a triangular strip conveying method, when the welding wire is conveyed to the included angle between the upper side of the welding bead and the groove of the second workpiece and stays for 0.5-1 s, and then is obliquely pulled downwards to the position, connected with the first workpiece, of the lower side of the molten pool and is far from the front end 1/4 of the molten pool, so as to ensure that the two sides of the welding bead are fully fused with the base metal.

Further, a second layer weld of the filler layer welds, comprising:

first welding: the size of the welding leg is 3-6 mm, and the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun and the first workpiece is 15-35 degrees, the back inclination angle between the welding gun and the welding line direction is 60-85 degrees, and a linear reciprocating strip conveying method is adopted;

and (3) welding the rest channels: the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun and the bevel face is 40-70 degrees, the back inclination angle between the welding gun and the welding line direction is 60-70 degrees, and a small crescent strip conveying method or a small inclined circle strip conveying method is adopted; when the welding wire is conveyed to the lower side of the welding bead, the welding wire is pressed back to the position with the width of the upper welding seam of 1/2-2/3;

and in the welding process of the second layer, the angle between the surface of the welding seam and the non-welded bevel face is always ensured to be not less than 90 degrees until the second layer is welded.

Further, the third and remaining layer welds of the filler weld include:

first welding: the size of the welding leg is 3-6 mm, and the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun and the first workpiece is 15-35 degrees, the back inclination angle between the welding gun and the welding line direction is 60-85 degrees, and a linear reciprocating strip conveying method is adopted;

welding a middle channel: adopting a left welding method, wherein the thickness of a welding seam is 3-6 mm, the lower included angle between a welding gun and the surface of the welding seam is 75-95 degrees, the back inclination angle between the welding gun and the welding seam direction is 60-70 degrees, adopting a linear reciprocating strip conveying method or a small inclined circle strip conveying method, and when a welding wire conveys a strip to the lower side of the welding seam, pressing back the upper welding seam at the position of 1/2-2/3;

and (3) final welding: the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun and the bevel face is 40-70 degrees, the back inclination angle between the welding gun and the welding line direction is 60-70 degrees, and a small crescent strip conveying method or a small inclined circle strip conveying method is adopted; when the welding wire is conveyed to the lower side of the welding bead, the welding wire is pressed back to the position with the width of the upper welding seam of 1/2-2/3;

and in the welding process of the third layer and the rest layers, the angle between the surface of the welding seam and the bevel face which is not welded is always ensured to be not less than 90 degrees until the filling layer is welded.

Further, the facing layer welds, including:

first welding: adopting a left welding method, wherein in the welding process, the included angle between a welding gun and the first workpiece is 25-55 degrees, the back inclination angle between the welding gun and the welding seam direction is 60-90 degrees, and fusing 1-2 mm of the first workpiece edge by adopting a straight-line reciprocating strip conveying method;

welding a middle channel: adopting a left welding method, wherein the thickness of a welding seam is 3-6 mm, the lower included angle between a welding gun and the surface of the welding seam is 75-95 degrees, the back inclination angle between the welding gun and the welding seam direction is 60-70 degrees, adopting a linear reciprocating strip conveying method or a small inclined circle strip conveying method, and when a welding wire conveys a strip to the lower side of the welding seam, pressing back the upper welding seam at the position of 1/2-2/3;

and (3) final welding: in the welding process, the lower included angle between a welding gun and the surface of the welding seam is 65-95 degrees, the backward inclination angle between the welding gun and the welding seam is 65-85 degrees, a linear reciprocating strip conveying method is adopted, the center of a fusion line on the upper side of the welding seam and the center of a fusion line of the welding seam is used as a center for conveying the strip, and the welding seam and the edge of the groove of the second workpiece are fused by 0.5-1 mm.

Further, before the welding of the priming layer, the T-shaped joint groove welding method further comprises tack welding, wherein the tack welding distance is 500-600 mm.

Further, the weld seam of the spot welding is divided into two layers: the length of a first layer of welding seams is 80-100 mm, and the size of a welding leg is 5-6 mm; the second layer of welding seam is located the centre of first layer welding seam, and welding seam length is 40 ~ 60mm, and the leg size is 7 ~ 8mm, and the welding seam joint of twice welding seam staggers more than 20mm to make things convenient for follow-up welding.

According to the technical scheme, the groove welding method for the T-shaped joint is suitable for various types of T-shaped joints. The T-joint includes a first workpiece and at least one second workpiece. For example, when a box beam is welded, a reinforcing plate is arranged between a web and a cover plate, the cover plate serves as a first workpiece, and the web and the reinforcing plate serve as second workpieces. The part to be connected of the first workpiece and the second workpiece is a welding position, a single V groove is arranged on the welding position, namely the groove is only arranged on the second workpiece, and the surface to be welded of the second workpiece forms a groove surface of the single V groove. The angles of the bevel surfaces of the second workpieces can be completely the same, partially the same or completely different, for example, when the box-shaped beam is welded, the bevel angle of the web is 45 degrees, the bevel angle of the reinforcing plate is 15 degrees, the double bevel T-shaped joints belong to different angles, and compared with the same bevel angle, the double bevels with different angles can reduce the filling amount of welding wires during welding and reduce welding deformation. Correspondingly, the welding difficulty is correspondingly improved due to different groove angles, and the T-shaped joint groove welding method provided by the invention can be used for welding a common single V groove and can also be used for welding double grooves with different angles or multi-grooves with different angles with higher difficulty.

The groove welding method of the T-shaped joint mainly comprises the steps of priming layer welding; welding the filling layer; and the cover layer is welded in three steps, wherein the welding quantity of the filler layer is the largest, the welding wire filling area is the largest, and therefore the cover layer is the most critical step for influencing the welding quality. In the groove welding method of the T-shaped joint, the filling layer welding adopts multilayer multi-pass welding, and the thickness of each welding line in each layer of welding line is controlled to be uniform and consistent when the multilayer multi-pass welding is carried out, so that the angle between the surface of the welding line and the non-welded bevel face is not less than 90 degrees, and the joint of the welding line and the web plate groove is fully fused. The defect that the welding seam and the web bevel face are not fused can be overcome.

Research finds that the main occurrence reason of the non-fusion defect of the welding seam and the workpiece bevel face in the prior art is as follows: in groove weld multilayer multi-pass welding, the first weld of each layer of weld is flat fillet welding, the second weld is transverse welding, and the transverse welding is characterized by high welding speed, for example, the conventional welding speed is 300-700 mm/min, the common welding speed for transverse welding is 550-700 mm/min, the thickness of the weld is small, the thickness of the weld is wide at the bottom and narrow at the top due to the accumulation of weld sizes, the surface of the weld is not perpendicular to the first workpiece, the included angle between the surface of the weld and the residual unwelded bevel face is reduced and is less than 90 degrees, the accessibility of welding electric arc is reduced, and the final weld of each layer of weld welded to the bevel face is easy to generate an unwelded defect.

Compared with the prior art, the method for welding the T-shaped joint groove provided by the invention has the advantages that when the filling layer is welded in multiple layers and multiple channels, the thickness of each welding seam in each layer of welding seam is uniform, the angle between the surface of the welding seam and the non-welded groove surface is not less than 90 degrees, the joint of the welding seam and the web plate groove is fully fused, and the defect that the welding seam and the web plate groove surface are not fused in the prior art is overcome.

Drawings

FIG. 1A is a first schematic diagram of a groove structure of a T-joint in the groove welding method of the T-joint in the embodiment of the present invention;

FIG. 1B is a schematic diagram of a groove structure of a T-joint in the groove welding method of the T-joint in the embodiment of the present invention;

FIG. 1C is a schematic diagram of a groove structure of a T-joint in the groove welding method of the T-joint in the embodiment of the present invention;

FIG. 1D is a fourth schematic diagram of a groove structure of a T-joint in the groove welding method of the T-joint in the embodiment of the present invention;

FIG. 2 is a schematic diagram of a welding principle of a T-joint groove welding method in the prior art;

FIG. 3 is a schematic diagram of a welding principle of a groove welding method for a T-shaped joint in the embodiment of the present invention;

FIG. 4 is a schematic view of the welding principle of the priming layer of the groove welding method of the T-shaped joint in the embodiment of the present invention;

FIG. 5 is a schematic diagram illustrating a first layer welding principle of a filling layer of the groove welding method for a T-shaped joint in the embodiment of the present invention;

FIG. 6 is a schematic view of a welding attitude of the torch of FIG. 5;

FIG. 7 is a schematic diagram illustrating a second layer welding principle of a filling layer in the groove welding method for a T-shaped joint according to the embodiment of the present invention;

FIG. 8 is a schematic diagram illustrating a third layer welding principle of a filler layer in the groove welding method for a T-shaped joint according to the embodiment of the present invention;

FIG. 9 is a schematic diagram illustrating a first welding principle of a facing layer of the groove welding method for a T-joint according to the embodiment of the present invention;

fig. 10 is a schematic diagram illustrating a final welding principle of a cover layer of the T-joint groove welding method in the embodiment of the present invention.

Description of reference numerals: 1-a first workpiece; 2-second workpiece, 21-second workpiece one, 22-second workpiece two, 23-second workpiece three; 3-bevel face; 4-a welding gun; 5-welding seams.

Detailed Description

In order to make the present application more clearly understood by those skilled in the art to which the present application pertains, the following detailed description of the present application is made with reference to the accompanying drawings by way of specific embodiments.

In the embodiment of the invention, the groove welding method for the T-shaped joint is suitable for various types of T-shaped joints. Referring to fig. 1 to 4, the T-joint includes a first workpiece 1 and at least one second workpiece 2, the to-be-connected portion of the first workpiece 1 and the second workpiece 2 is a welding position, and a single V-shaped groove is arranged on the welding position, that is, the groove is only arranged on the second workpiece; the surfaces to be welded of the second workpieces 2 form the bevel surfaces 3 of the single V-groove, and when the number of the second workpieces is more than two, the angles of the bevel surfaces 3 of the second workpieces 2 are completely the same, partially the same or completely different.

For example, when a box beam is welded, a reinforcing plate is arranged between a web and a cover plate, the cover plate serves as a first workpiece, and the web and the reinforcing plate serve as second workpieces. The angles of the bevel faces of the respective second workpieces may be arranged to be identical, partially identical or completely different. For example, when a box beam is welded, the bevel angle of the web is 45 degrees, the bevel angle of the reinforcing plate is 15 degrees, and the double-bevel T-shaped joint belongs to double-bevel T-shaped joints with different angles, as shown in fig. 1A; for example, when a box beam is welded, the bevel angle of the web is 45 degrees, the bevel angle of the reinforcing plate is also 45 degrees, and the reinforcing plate belongs to a double-bevel T-shaped joint with the same angle, as shown in fig. 1B; or a certain T-joint comprises a first workpiece 1 and three second workpieces 2, and the bevel angles of the three second workpieces 2 are 45 °, 45 ° and 3 ° in sequence, which belong to a three-bevel T-joint with the same part of angles, as shown in fig. 1C; the most common T-joint is shown in fig. 1D and comprises a first workpiece 1 and a second workpiece 2, the bevel angle being 45 °. Of course, the applicable objects of the T-joint groove welding method provided by the present invention are not limited to the above four examples.

Compared with the same bevel angle, the multi-bevel of different angles can reduce the filling amount of welding wires during welding and reduce welding deformation. Correspondingly, the welding difficulty is correspondingly improved due to different groove angles, and the T-shaped joint groove welding method provided by the invention can be used for welding a common single V groove and can also be used for welding double grooves with different angles or multi-grooves with different angles with higher difficulty.

The invention provides a T-shaped joint groove welding method which specifically comprises the following steps: welding a priming coat; welding the filling layer; and (6) welding the cover layer. Wherein, the filling layer welding adopts multilayer multi-pass welding; when multilayer multi-pass welding is controlled, the thickness of each welding seam in each layer of welding seams is uniform, namely the thickness of each welding seam is the same and the thickness distribution is uniform, and the thickness of each welding seam in each layer of welding seams is the same, so that the angle between the surface of each welding seam and the non-welded bevel face 3 is not less than 90 degrees, as shown in fig. 1 to 4.

The T-joint groove welding method provided by the present invention is described in detail below with reference to a typical welding case:

in this embodiment, the T-joint groove welding method provided by the present invention was used to weld a box beam of a railway vehicle. Referring to fig. 2, the original welding process of the box beam is as follows: the connecting weld joints of the box beam cover plate (i.e. the first workpiece 1), the web plate (i.e. the second workpiece 22) and the reinforcing plate (i.e. the second workpiece 21) are in the form of T-shaped double-groove angle joint joints with different angles, and as shown in fig. 2, a multilayer multi-pass welding method is adopted, and MAG welding (metal active gas welding, gas shielded welding for short) is adopted to be matched with MAG solid welding wires for welding.

In the groove weld multilayer multi-pass welding of the box-shaped beam, the first weld of each layer of weld is flat fillet welding, the size of a weld leg is about 5-6 mm, the second weld is horizontal welding, the thickness of the weld is about 3-5 mm, the angle of a web groove is only 15 degrees and is different from the angle of a conventional single V groove 45 degrees, in the early actual production process, when a reinforcing plate groove is welded to a web groove, the width of the weld is narrow at the bottom and the top due to the accumulation of the sizes of the weld 5, the surface of the weld is not perpendicular to a cover plate, the included angle between the surface of the weld and the web groove is reduced and is about 60 degrees, the accessibility of welding electric arc is reduced, the last weld of each layer of weld welded to the web plate is caused to generate an incomplete penetration defect, the thickness of the plate is thick, the repair is difficult, and the welding quality cannot meet the technical requirements of.

After the technology is upgraded, aiming at the double-crevasse T-shaped joint with different angles, the T-shaped joint groove welding method provided by the invention is adopted, the process steps are unchanged, and the welding still comprises priming layer welding; welding the filling layer; and (6) welding the cover layer. MAG welding (gas metal arc welding, short for gas shielded welding) is adopted to be matched with MAG solid welding wire for welding. Before welding, cleaning before welding and tack welding are required, and the process requirements are as follows:

(1) Cleaning before welding

Polishing two ends of tack welding to be in a slope shape, cleaning oil stain, water and rust on the surface of the groove and within 30mm of the outer side of the groove until the metal luster is exposed, and cutting off the globular oxide at the front end of the welding wire on a welding gun.

(2) Requirement for tack welding

Because the cover plate of box girder and the restraint stress of web are great, the spot welding should be divided into two layers: the length of a first layer of welding seams is 80-100 mm, and the size of a welding leg is 5-6 mm; the second layer of welding seam is located the centre of first layer welding seam, and welding seam length is 40 ~ 60mm, and the leg size is 7 ~ 8mm, and the welding seam joint of twice welding seam staggers more than 20mm to make things convenient for follow-up welding. The distance between two adjacent spot welding seams is 500-600 mm.

The specific welding process is as follows:

1. welding a priming coat: adopting a left welding method or a right welding method, wherein the size of a welding leg is 5-6 mm; during welding, the included angle α 1 between the welding gun 4 and the first workpiece 1 (cover plate) is 15 ° to 35 °, as shown in fig. 4, and the included angle α 1 is preferably 20 ° to 30 °, for example, 22 °, 24 °, 25 °, 27 °, 29 °. The front inclination angle of the welding gun 4 to the welding direction (the advancing direction of the welding gun during welding is the welding direction, the included angle with the welding direction is the front inclination angle when the included angle is measured, and the included angle with the welding line direction is the back inclination angle) is 70-110 degrees, such as 75 degrees, 80 degrees, 85 degrees, 90 degrees, 103 degrees, 105 degrees and the like; the method delays the propulsion of liquid metal in the molten pool by using the blowing action of the electric arc, so as to prolong the retention time of the electric arc in the molten pool, increase the weld penetration when obtaining larger heat of the electric arc, ensure the penetration of the root of the weld and good fusion property, and simultaneously obtain the weld with full and smooth appearance.

2. And (3) welding a filling layer: and (4) adopting a left-hand welding method, and after the welding of the filling layer is finished, reserving the welding bead for 1-3 mm in depth and welding the cover surface layer. The welding of filling layer is multilayer multichannel welding, and specific welding strategy is: the ith layer adopts i welding, i belongs to [2, N ], and N is the total number of layers of the multilayer and multi-pass welding. That is, the first layer adopts one welding, and the second layer uses twice welding, and the third layer uses three welding, and so on.

2-1, first layer welding of filling layer welding: the size of the welding leg is 7-8 mm; during welding, the included angle α 2 between the welding gun 4 and the first workpiece 1 (cover plate) is 20 ° to 40 °, as shown in fig. 5, and the included angle α 2 is preferably 25 ° to 35 °, for example, 25 °, 27 °, 29 °, 32 °, 34 °, and the like. The back-tilt angle α 3 of the welding gun 4 with respect to the weld direction is 70 ° to 90 °, for example, 75 °, 77 °, 79 °, 82 °, 84 °, 88 °, as shown in fig. 6.

And the first layer of the filling layer adopts a circular strip conveying method, a crescent strip conveying method, a zigzag strip conveying method or a triangular strip conveying method, when the welding wire conveys the strip to the included angle between the upper side of the welding bead and the bevel face 3 of the second workpiece 21 (reinforcing plate) for 0.5 s-1 s, the welding wire is quickly and downwards obliquely pulled to the position, away from the front end 1/4 of the welding pool, of the connecting position of the lower side of the welding pool and the first workpiece 1 (cover plate), so as to ensure that the two sides of the welding line are fully fused with the base metal.

2-2, second layer welding of filling layer welding: and (5) multi-layer and multi-pass welding.

First welding: the size of the welding leg is 3-6 mm, the thickness of the welding seam is 3-6 mm, and the optimal thickness is 4-5 mm; during welding, the included angle between the welding gun 4 and the first workpiece 1 (cover plate) is 15 ° to 35 °, preferably 20 ° to 30 °, such as 22 °, 24 °, 25 °, 27 °, 29 °, and the like. The back dip angle of the welding gun 4 and the welding line direction is 60-85 degrees, and a straight line reciprocating strip conveying method is adopted.

And (3) second welding: the thickness of the welding line is 3-6 mm, preferably 4-5 mm, and is consistent with that of the first welding line; during welding, the included angle α 5 between the welding gun 4 and the bevel face 3 of the second workpiece 21 (reinforcing plate) is 40 ° to 70 °, as shown in fig. 7, and the included angle α 5 is preferably 45 ° to 65 °, for example, 45 °, 47 °, 50 °, 54 °, 58 °, 62 °, or the like. The back inclination angle of the welding gun 4 and the welding line direction is 60-70 degrees, such as 60 degrees, 62 degrees, 64 degrees, 68 degrees, 70 degrees and the like, and a small crescent strip transporting method or a small inclined circle strip transporting method is adopted; when the welding wire is conveyed to the lower side of the welding bead, the welding wire is pressed back to the position of the upper welding seam width 1/2-2/3.

In the second layer welding process, the thickness of the second and the rest welding seams is consistent with that of the first welding seam, so that the surface of the welding seam 5 is vertical to the first workpiece 1 (cover plate), the subsequent arrangement of the welding seam layer is facilitated, the angle between the surface of the welding seam and the non-welded bevel face 3 is always ensured not to be smaller than 90 degrees, and the welding process is completed until the second workpiece 21 (reinforcing plate) is welded.

In the second layer welding process, the first welding is flat fillet welding (with welding foot size), the rest welding is transverse welding (without welding foot size), the welding speed is slowed down as much as possible during transverse welding, for example, the conventional welding speed is 100-700 mm/min, the transverse welding speed is 100-450 mm/min, for example, 150mm/min, 200mm/min, 250mm/min, 300mm/min, 350mm/min, 400mm/min and the like, and the thickness of the welding seam is increased.

2-3, third layer welding of filling layer welding: and multiple layers and multiple welding, wherein the first welding operation and the last welding operation of each layer are consistent with the first welding operation and the last welding operation of the second layer.

First welding: the size of the welding leg is 3-6 mm, and the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun 4 and the first workpiece 1 (cover plate) is 15-35 degrees, the back inclination angle between the welding gun 4 and the welding line direction is 60-85 degrees, and a linear reciprocating strip conveying method is adopted. This process is in the first pass of the second layer.

Welding a middle channel: and (3) adopting a left welding method, wherein the thickness of the welding line is 3-6 mm, preferably 4-5 mm, and is consistent with that of the first welding line. The lower angle α 6 of the welding gun 4 to the surface of the weld is 75 ° to 95 °, as shown in fig. 8, and the angle α 6 is preferably 80 ° to 90 °, for example, 82 °, 85 °, 87 °, 90 °, and the like. The back inclination angle of the welding gun 4 to the welding line direction is 60 to 70 degrees, such as 60 degrees, 62 degrees, 64 degrees, 68 degrees, 70 degrees, and the like. And (3) adopting a linear reciprocating strip conveying method or a small inclined circle strip conveying method, and when the welding wire conveys the strip to the lower side of the welding bead, pressing the upper welding seam back at the position of 1/2-2/3 of the width of the welding seam.

And (3) final welding: the thickness of the welding seam is 3-6 mm; in the welding process, the included angle between the welding gun 4 and the bevel face 3 is 40-70 degrees, the back inclination angle between the welding gun 4 and the welding line direction is 60-70 degrees, and a small crescent strip conveying method or a small inclined circle strip conveying method is adopted; when the welding wire is conveyed to the lower side of the welding bead, the welding wire is pressed back to the position of the upper welding seam width 1/2-2/3. This process is the last step of the second layer.

The third layer welding operation method for welding the filling layer can be applied to the last layer of the filling layer, namely the third layer welding operation method for welding the filling layer is adopted when the filling layer is welded from the third layer.

In the process of welding the third layer and the residual layers, the thickness of the welding seam welded by the second layer and the residual layers is consistent with that of the first welding seam, so that the surface of the welding seam 5 is vertical to the first workpiece 1 (cover plate), the subsequent arrangement of the welding seam layers is facilitated, and the angle between the surface of the welding seam and the non-welded bevel face 3 is always ensured not to be smaller than 90 degrees until the filling layer is welded.

In the welding process of the third layer and the rest layers, the first welding is flat fillet welding (with welding foot size), the rest welding is transverse welding (without welding foot size), and the welding speed is slowed down as much as possible during transverse welding, for example, the conventional welding speed is 300-700 mm/min, and the transverse welding speed is 300-650 mm/min, so that the thickness of a welding seam is increased.

3. And (3) welding a cover layer: and (5) multi-layer and multi-pass welding.

First welding: in the left-hand welding method, the included angle α 7 between the welding gun 4 and the first workpiece 1 (cover plate) is 25 ° to 55 ° as shown in fig. 9, and the included angle α 7 is preferably 30 ° to 50 °, such as 32 °, 35 °, 37 °, 40 °, 43 °, 45 °, 48 °, and the like. The back inclination angle of the welding gun 4 and the welding seam direction is 60-90 degrees, such as 62 degrees, 65 degrees, 70 degrees, 75 degrees, 77 degrees, 79 degrees, 82 degrees, 84 degrees, 88 degrees and the like, and the edge of the first workpiece 1 (cover plate) is fused by adopting a straight line reciprocating strip conveying method for 1-2 mm.

Welding a middle channel: adopting a left welding method, wherein the thickness of a welding seam is 3-6 mm, the lower included angle between a welding gun 4 and the surface of the welding seam is 75-95 degrees, the backward inclination angle between the welding gun 4 and the direction of the welding seam is 60-70 degrees, adopting a linear reciprocating strip conveying method or a small inclined circle strip conveying method, and when a welding wire conveys a strip to the lower side of the welding seam, pressing back the upper welding seam in the width of 1/2-2/3. The process is welded with the middle channel of the third layer of the filling layer.

And (3) final welding: in the welding process, the lower included angle α 8 between the welding gun 4 and the surface of the welding seam 5 is 65 ° to 95 °, as shown in fig. 10, and the included angle α 8 is preferably 70 ° to 90 °, such as 72 °, 75 °, 77 °, 80 °, 83 °, 85 °, 88 °, and the like. The back inclination angle of the welding gun 4 to the weld direction is 65 ° to 85 °, for example, 62 °, 65 °, 70 °, 75 °, 77 °, 79 °, 82 °, 84 °, and the like. And (3) carrying the strip by adopting a linear reciprocating strip carrying method, wherein the center of a fusion line on the upper side of the welding wire and the fusion line of the welding wire is used as the center, the upper welding wire and the edge of the groove of the second workpiece 22 (web plate) are fused by 0.5-1 mm, and the welding wire is controlled not to be undercut and not to transversely swing. During arc closing, the arc pits are filled with welding seams to avoid arc pit cracks, so that the welding quality is ensured, and the welding appearance is well formed.

In other embodiments, the welding of each welding seam may also adopt a zigzag strip transporting method, a reversed crescent strip transporting method, a triangular strip transporting method, and other strip transporting methods, which are not limited in this application.

The T-shaped double-groove angle joint welding method for the box beam provided by the embodiment of the invention is adopted to weld the T-shaped double-groove angle joint of the box beam at different angles, the incomplete fusion defect and undercut are avoided through manual visual inspection, the forming is attractive, the detection result is qualified through ultrasonic nondestructive detection, and the welding quality is ensured.

Through the embodiment, the invention has the following beneficial effects or advantages:

1) according to the T-shaped joint groove welding method provided by the invention, when the filling layer is welded in multiple layers and multiple channels, the thickness of each welding seam in each layer of welding seam is uniform, so that the angle between the surface of the welding seam and the bevel face which is not welded is not less than 90 degrees, the joint of the welding seam and the web groove is fully fused, and the defect that the welding seam and the web bevel face are not fused in the prior art is overcome.

2) The groove welding method for the T-shaped joint, provided by the invention, is not only suitable for welding a common horizontal T-shaped single V groove joint, but also is particularly suitable for welding a horizontal T-shaped double groove or multi-groove joint with different angles, and has the advantages of considering both the welding quality and the welding wire filling amount and reducing the production cost.

3) According to the T-shaped joint groove welding method provided by the invention, the included angle between the welding gun and the surface of the workpiece, the included angle between the welding gun and the bevel face and the inclination angle of the welding gun are controlled when each welding seam is welded, the full penetration welding seam is obtained by adopting different conventional welding gun angles and operation methods, the appearance of the welding seam is full and smooth, the welding formation is good, the welding quality is ensured, and the ultrasonic nondestructive detection can be carried out.

While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.