CN-121988836-A - Back-gouging-free welding process for double-sided V-shaped butt welding seam

CN121988836ACN 121988836 ACN121988836 ACN 121988836ACN-121988836-A

Abstract

The invention discloses a back-gouging-free welding process for double-sided V-shaped butt welds, which comprises the following steps of B1, finishing blanking and forming of eight welding pieces, respectively processing double-sided symmetrical grooves at welding positions where all welding pieces are butted, arranging blunt edges at the root parts of the grooves, B2, cleaning impurities in a to-be-welded area of the eight welding pieces, B3, pairwise forming four groups of the eight welding pieces and finishing positioning welding, and setting gaps between the welding pieces in pairs, B4, fixing the four groups of the welding pieces according to a group of flat welding positions, two groups of vertical welding positions and a group of overhead welding positions, B5, using a welding machine to weld the four groups of welding pieces, respectively adopting corresponding postures for bottoming the welding pieces at the flat welding positions and the overhead welding positions, respectively adopting a vertical welding mode and a vertical welding mode for bottoming, and B6, using gas for protection welding to fill and cover the welding pieces in the flat position state. The invention realizes full penetration welding without back chipping and reduces the sensitivity of the weld joint gap precision.

Inventors

ZHANG ZHIGUANG
WANG GUOYOU
Wei Shoupan
ZHU MINGTAO
JING XIN
WU SHIQIANG

Assignees

徐州徐工矿业机械有限公司

Dates

Publication Date: 20260508
Application Date: 20260403

Claims (10)

1. The back chipping-free welding process for the double-sided V-shaped butt welding seam is characterized by comprising the following steps of: step B1, blanking and forming of eight welding pieces are completed, double-sided symmetrical grooves are respectively processed at the welding seam positions of all the welding pieces in butt joint, blunt edges are arranged at the root parts of the grooves, and the groove sizes of the eight welding pieces are consistent; step B2, removing impurities in the to-be-welded areas of the eight welding pieces; step B3, two pairs of eight welding pieces are divided into four pairs of welding pieces, positioning welding is completed, and gaps are reserved between the pairs of welding pieces; step B4, fixing the four groups of welding parts according to a group of flat welding positions, two groups of vertical welding positions and a group of overhead welding positions; step B5, using a welding machine to prime and weld the four groups of welding pieces, respectively priming welding pieces at the flat welding position and the bottom welding position by adopting corresponding postures, and priming welding pieces at the vertical welding position by adopting a vertical upward welding mode and a vertical downward welding mode; and step B6, filling and covering the welding piece in a flat welding position state by using gas shielded welding.
2. The back-gouging-free welding process of a double-sided V-shaped butt weld of claim 1, wherein: in the step B1, symmetrical grooves are machined on two sides of eight welding pieces, the blunt edge size between the symmetrical grooves is B, B is not less than 1.5mm and not more than 2.5mm, the thickness of the welding pieces is t and not less than 20mm, the groove angle of the welding pieces is beta, and beta is not less than 30 degrees and not more than 45 degrees.
3. The back-gouging-free welding process of a double-sided V-shaped butt weld of claim 1, wherein: In the step B2, the groove parts of eight welding parts are welding areas, and impurities affecting the welding quality are removed by using brushes within the range of 50mm on two sides of the welding areas.
4. The back-gouging-free welding process of a double-sided V-shaped butt weld of claim 1, wherein: In the step B3, the groove sides of the two welding pieces are in butt joint, four groups of welding pieces are paired together, the gap size of each group of welding pieces after the joint is a is 3 mm-5 mm, and the misalignment amount of each group of welding pieces is 1.5mm.
5. The back-gouging-free welding process of a double-sided V-shaped butt weld of claim 1, wherein: In the step B4, the first group of welding pieces are arranged at a flat welding position, the second group of welding pieces and the third group of welding pieces are arranged at a vertical welding position, and the fourth group of welding pieces are arranged at an overhead welding position; In the step B5, the welding machine is adjusted to be in an STT mode when the welding piece at the first group of flat welding positions is subjected to backing welding, the welding wire of the welding gun points to the blunt edge at one end of the welding piece, the included angle between the welding gun and the welding direction is 75-90 degrees, the included angle between the welding gun and the surface of the welding piece is 90+/-5 degrees, the welding current is 110A-130A, the welding voltage is 15V-16V, the welding speed is 130 mm/min-140 mm/min, and the dry extension length of the welding wire is 10 mm-15 mm; The welding machine is adjusted to be in an STT mode when the second vertical upward welding piece is subjected to backing welding, the welding wire of the welding gun points to the blunt edge at one end of the welding piece, the included angle between the welding gun and the welding direction is 80-90 degrees, the included angle between the welding gun and the surface of the welding piece is 90+/-5 degrees, the welding current is 110A-130A, the welding voltage is 14.7V-15.5V, the welding speed is 100-120 mm/min, and the dry extension length of the welding wire is 10-15 mm; the welding machine is adjusted to be in an STT mode when the third assembly downward welding piece is subjected to backing welding, a welding wire of the welding gun points to the blunt edge at one end of the welding piece, an included angle between the welding gun and the welding direction is 75-90 degrees, an included angle between the welding gun and the surface of the welding piece is 90+/-5 degrees, welding current is 140-160A from top to bottom during welding, welding voltage is 16-17V, welding speed is 130-150 mm/min, and dry extension length of the welding wire is 10-15 mm; And when the fourth group of overhead welding pieces are primed, the welding machine is adjusted to be in an STT mode, the welding wire of the welding gun points to the blunt edge at one end of the welding piece, the included angle between the welding gun and the welding direction is 80-90 degrees, the included angle between the welding gun and the surface of the welding piece is 90+/-5 degrees, the welding current is 100-120A, the welding voltage is 14-15V, the welding speed is 105-120 mm/min, and the dry extension length of the welding wire is 10-15 mm.
6. The back-gouging-free welding process of a double-sided V-shaped butt weld of claim 5, wherein: when the first group of flat welding position welding parts are subjected to backing welding, a left welding method is adopted, and/or, When the welding pieces at the first assembly welding position, the second assembly welding piece at the upward direction, the third assembly welding piece at the downward direction and the fourth assembly welding piece are subjected to bottoming, the welding gun swings in a crescent shape or a zigzag shape.
7. The back-gouging-free welding process of a double-sided V-shaped butt weld of claim 1, wherein: In the step B6, after the priming welding of the four groups of welding pieces is finished, filling and covering surfaces are all carried out at a flat welding position, welding is carried out by adopting a left welding method during welding, an included angle between a welding gun and the welding direction is 65-80 degrees, an included angle between the welding gun and the surface of the welding piece is 90+/-5 degrees, welding current is 280-320A, welding voltage is 30-34V, welding speed is 250-350 mm/min, and welding wire dry extension length is 10-20 mm.
8. The back-gouging-free welding process of a double-sided V-shaped butt weld of claim 1, wherein: in the step B5 and the step B6, solid welding wires which are matched with a base metal in equal strength are selected as welding materials, the diameter of the welding wires is 1.2mm, and 84 percent Ar+16 percent CO 2 is selected as shielding gas; in step B6, the filling and covering of the welding plate may be performed by manual welding or robot welding.
9. The back-gouging-free welding process of a double-sided V-shaped butt weld of claim 1, further comprising: and B7, performing appearance inspection, ultrasonic flaw detection, magnetic powder flaw detection, internal macroscopic metallographic inspection and mechanical property inspection on the weld joint.
10. The back-gouging-free welding process of a double-sided V-shaped butt weld of claim 1, wherein: In the step B5, when the welding pieces at different welding positions are primed, a short-circuit transitional arc is adopted; in step B6, a jet transition arc is used to fill and cap the weld.

Description

Back-gouging-free welding process for double-sided V-shaped butt welding seam Technical Field The invention relates to a back-gouging-free welding process for a double-sided V-shaped butt welding seam, and belongs to the technical field of welding. Background In the field of medium plate welding, for a double-sided V-shaped butt welding seam, a front priming and back gouging mode is generally adopted to ensure full penetration of the welding seam. This not only increases the number of man-hours for assistance, but also causes noise, dust, and the like to affect the health of the worker. Disclosure of Invention According to the defects existing in the prior art, the invention provides the back chipping-free welding process for the double-sided V-shaped butt welding seam, which meets the multi-position backing welding operation of the double-sided V-shaped butt welding seam, solves the back chipping and polishing problems on the premise of ensuring the full penetration of the welding seam, is beneficial to shortening the manufacturing period and improving the production environment of operators. The invention is realized according to the following technical scheme: the invention provides a back-gouging-free welding process for a double-sided V-shaped butt welding seam, which comprises the following steps of: step B1, blanking and forming of eight welding pieces are completed, double-sided symmetrical grooves are respectively processed at the welding seam positions of all the welding pieces in butt joint, blunt edges are arranged at the root parts of the grooves, and the groove sizes of the eight welding pieces are consistent; step B2, removing impurities in the to-be-welded areas of the eight welding pieces; step B3, two pairs of eight welding pieces are divided into four pairs of welding pieces, positioning welding is completed, and gaps are reserved between the pairs of welding pieces; step B4, fixing the four groups of welding parts according to a group of flat welding positions, two groups of vertical welding positions and a group of overhead welding positions; step B5, using a welding machine to prime and weld the four groups of welding pieces, respectively priming welding pieces at the flat welding position and the bottom welding position by adopting corresponding postures, and priming welding pieces at the vertical welding position by adopting a vertical upward welding mode and a vertical downward welding mode; and step B6, filling and covering the welding piece in a flat welding position state by using gas shielded welding. In some embodiments, in step B1, two sides of eight welding pieces are machined into symmetrical grooves, the blunt edge between the symmetrical grooves has a size B, B is 1.5mm less than or equal to 2.5mm, the thickness of the welding pieces is t, t is more than or equal to 20mm, the groove angle of the welding pieces is beta, and beta is more than or equal to 30 degrees and less than or equal to 45 degrees. In some embodiments, in step B2, the bevel of the eight welded parts is a welding area, and the impurities affecting the welding quality are removed by using brushes within 50mm of both sides of the welding area. In some embodiments, in step B3, the bevel sides of the two welding pieces are butted, four welding pieces are paired in groups, the gap size of each welding piece is a after the welding piece is spliced, and a is 3≤a≤5 mm, and the misalignment amount of each welding piece is 1.5mm. In some embodiments, in step B4, the first set of welds is disposed in a flat position, the second and third sets of welds are disposed in a stand-up position, and the fourth set of welds are disposed in a stand-up position; In the step B5, the welding machine is adjusted to be in an STT mode when the welding piece at the first group of flat welding positions is subjected to backing welding, the welding wire of the welding gun points to the blunt edge at one end of the welding piece, the included angle between the welding gun and the welding direction is 75-90 degrees, the included angle between the welding gun and the surface of the welding piece is 90+/-5 degrees, the welding current is 110A-130A, the welding voltage is 15V-16V, the welding speed is 130 mm/min-140 mm/min, and the dry extension length of the welding wire is 10 mm-15 mm; The welding machine is adjusted to be in an STT mode when the second vertical upward welding piece is subjected to backing welding, the welding wire of the welding gun points to the blunt edge at one end of the welding piece, the included angle between the welding gun and the welding direction is 80-90 degrees, the included angle between the welding gun and the surface of the welding piece is 90+/-5 degrees, the welding current is 110A-130A, the welding voltage is 14.7V-15.5V, the welding speed is 100-120 mm/min, and the dry extension length of the welding wire is 10-15 mm; the welding machine is adjusted to be in an STT mode when the third assembly downwa