T-shaped joint double-beam laser wire-filling welding method capable of reducing porosity of welding seam
阅读说明：本技术 一种可降低焊缝气孔率的t型接头双束激光填丝焊接方法 (T-shaped joint double-beam laser wire-filling welding method capable of reducing porosity of welding seam ) 是由 彭进 于 2020-06-09 设计创作，主要内容包括：本发明涉及一种可降低焊缝气孔率的T型接头双束激光填丝焊接方法,立筋和基板之间预留间隙,在接头的两侧分别利用两束激光进行激光填丝焊接,第一束激光用于熔化固态焊丝,第二束激光熔化母材形成匙孔及熔池。本发明的焊接方法中在T型接头立筋和基板之间预留一定的间隙,沿焊接方向利用小能量的激光束预先熔化焊丝之后液态金属通过毛细作用填充进间隙中,间隙增大了激光熔透效果,而且形成匙孔的激光束前方的焊丝熔化呈液态不但能流入间隙中预先填充而且可以大大提高对形成匙孔的第二束激光束的能量吸收率,可以保证在T型接头两侧更易形成相互贯通的匙孔,有利于降低熔池中气泡的数量,从而降低焊缝气孔率。(The invention relates to a T-shaped joint double-beam laser wire-filling welding method capable of reducing the porosity of a welding seam. In the welding method, a certain gap is reserved between the T-shaped joint stud and the base plate, liquid metal is filled into the gap through capillary action after a small-energy laser beam is used for melting a welding wire in advance along the welding direction, the gap increases the laser penetration effect, the welding wire in front of the laser beam for forming the key hole is melted into a liquid state, the welding wire can flow into the gap for filling in advance, the energy absorption rate of a second laser beam for forming the key hole can be greatly improved, the key holes which are communicated with each other can be more easily formed on two sides of the T-shaped joint, the number of bubbles in a molten pool is favorably reduced, and the porosity of a welding line is reduced.)
1. A double-beam laser wire-filling welding method for a T-shaped joint capable of reducing porosity of a welding seam is characterized by comprising the following steps: a gap is reserved between the T-shaped joint stud and the base plate, two beams of laser are respectively utilized to carry out laser wire filling welding on two sides of the T-shaped joint, the first beam of laser is used for melting a solid welding wire, the second beam of laser melts a base material to form a keyhole and a molten pool, and light spots of the second beam of laser on two sides of the T-shaped joint coincide.
2. The double-beam laser wire-filling welding method for the T-shaped joint capable of reducing the porosity of the weld joint, according to claim 1, is characterized in that: the method specifically comprises the following steps:
s1, performing surface treatment on the stud and the base plate of the T-shaped joint before welding to remove impurities on the surface of the welded workpiece;
s2, fixing the T-shaped joint stud and the base plate on a welding fixture, and reserving a gap;
s3, arranging a laser on each of two sides of the T-shaped joint, and adjusting a light splitting module of the laser to enable the laser to split a first laser beam for melting a welding wire and a second laser beam for melting a base material to form a keyhole;
s4, adjusting second laser beams emitted by lasers on two sides of the T-shaped joint to enable light spots of the second laser beams on two sides of the T-shaped joint to coincide;
and S5, presetting an active agent in advance in the welding area, starting a laser and a wire feeder, and simultaneously spraying protective gas above the molten pool to prevent the molten pool from being oxidized, so as to carry out the T-shaped joint double-beam laser wire filling welding.
3. The double-beam laser wire-filling welding method for the T-shaped joint capable of reducing the porosity of the weld joint as claimed in claim 2, characterized in that: the laser is Nd: YAG laser, CO2A laser or a fiber laser.
4. The double-beam laser wire-filling welding method for the T-shaped joint capable of reducing the porosity of the weld joint as claimed in claim 1 or 2, wherein: the clearance between the T-shaped joint stud and the base plate is 0.01mm-0.5 mm.
5. The double-beam laser wire-filling welding method for the T-shaped joint capable of reducing the porosity of the weld joint as claimed in claim 2, characterized in that: the beam distance between the first laser beam and the second laser beam separated by the laser is 0.5-1.3 mm.
6. The double-beam laser wire-filling welding method for the T-shaped joint capable of reducing the porosity of the weld joint as claimed in claim 2, characterized in that: the protective gas is argon or helium.
Technical Field
The invention relates to the technical field of laser welding, in particular to a double-beam laser wire-filling welding method for a T-shaped joint of an aluminum alloy sheet, which can reduce the porosity of a welding seam.
Background
The aluminum alloy has the advantages of small specific gravity and elastic modulus, corrosion resistance and the like. Currently, aluminum alloy T-frame fuselage panels have been used in C919 large aircraft. The T-shaped structure of the aluminum alloy sheet can be welded by adopting a laser filler wire welding process. However, laser welding of aluminum alloys presents several problems, including: (1) the aluminum alloy has high reflectivity to laser, and the base material has low absorptivity to laser when the base material is not melted. (2) The cooling speed of the welding seam of the laser welding is high, bubbles in a molten pool are not easy to escape before the molten pool is solidified, and air holes are easy to form. At present, two sets of laser filler wire welding devices are adopted for a T-shaped structure of an aluminum alloy sheet and are respectively positioned on two sides of a fillet weld of a T-shaped joint for simultaneous welding. Because the diameter of a laser beam spot is small (generally 0.2 mm), poor stability of a keyhole in a welding process is easily caused, welding bubbles can be generated when the middle part or the bottom of the keyhole collapses, the welding bubbles can be easily generated when the keyhole formed by the laser beams on two sides of the T-shaped structure does not form a through structure, and when the welding bubbles do not escape from a molten pool before the molten pool is solidified, air holes are formed in a welding line to influence the quality of the welding line.
Disclosure of Invention
The invention aims to provide a T-shaped joint double-beam laser filler wire welding method capable of reducing the porosity of a welding seam, and aims to solve the problem that the porosity of the welding seam of the T-shaped joint double-beam laser filler wire welding of an aluminum alloy sheet in the prior art is high.
In order to solve the technical problems, the invention adopts the technical scheme that: a gap is reserved between a T-shaped joint stud and a base plate, two beams of laser are respectively utilized to carry out laser wire filling welding on two sides of the T-shaped joint, the first beam of laser is used for melting a solid welding wire, the second beam of laser is used for melting a base material to form a keyhole and a molten pool, and light spots of the second beam of laser on two sides of the T-shaped joint coincide.
The invention relates to a T-shaped joint double-beam laser wire-filling welding method capable of reducing the porosity of a welding seam, which comprises the following steps: the method specifically comprises the following steps:
s1, performing surface treatment on the stud and the base plate of the T-shaped joint before welding to remove impurities on the surface of the welded workpiece;
s2, fixing the T-shaped joint stud and the base plate on a welding fixture, and reserving a gap;
s3, arranging a laser on each of two sides of the T-shaped joint, and adjusting a light splitting module of the laser to enable the laser to split a first laser beam for melting a welding wire and a second laser beam for melting a base material to form a keyhole;
s4, adjusting second laser beams emitted by lasers on two sides of the T-shaped joint to enable the beam distance of the second laser beams emitted by the lasers on two sides to be 0 mm;
and S5, presetting an active agent in advance in the welding area, starting a laser and a wire feeder, and simultaneously spraying protective gas above the molten pool to prevent the molten pool from being oxidized, so as to carry out the T-shaped joint double-beam laser wire filling welding.
The invention relates to a T-shaped joint double-beam laser wire-filling welding method capable of reducing the porosity of a welding seam, which comprises the following steps: the laser is Nd: YAG laser, CO2A laser or a fiber laser.
The invention relates to a T-shaped joint double-beam laser wire-filling welding method capable of reducing the porosity of a welding seam, which comprises the following steps: the clearance between the T-shaped joint stud and the base plate is 0.01mm-0.5 mm.
The invention relates to a T-shaped joint double-beam laser wire-filling welding method capable of reducing the porosity of a welding seam, which comprises the following steps: the beam distance between the first laser beam and the second laser beam separated by the laser is 0.5-1.3 mm.
The invention relates to a T-shaped joint double-beam laser wire-filling welding method capable of reducing the porosity of a welding seam, which comprises the following steps: the protective gas is argon or helium.
The double-beam laser filler wire welding method for the T-shaped joint has the following beneficial effects:
in the welding method, a certain gap (the gap size is 0.01mm-1 mm) is reserved between the T-shaped joint stud and the base plate, and liquid metal is filled into the gap through capillary action after a small-energy laser beam is used for pre-melting a welding wire along the welding direction;
in the welding method, the distance between the laser beams for forming the keyhole by the second beams on two sides of the T-shaped joint is zero, so that the stability of penetrating the keyhole can be improved, and the generation of welding bubbles caused by the fact that the keyhole on two sides of the T-shaped joint cannot continuously form a penetrating keyhole in a molten pool is reduced;
in the welding method, because the small-energy laser beam is used for melting the welding wire in advance along the welding direction, the liquid metal is filled into the gap through the capillary action, so that the conditions that the requirements on the splicing gap and the welding line alignment are high and the requirements on the assembly conditions of welding production are strict due to the reserved gap and laser self-fusion welding (i.e. no welding wire or welding flux is added in the welding process) can be avoided;
in the welding method, after the small-energy laser melts the welding wire, the liquid metal at the end of the welding wire is contacted with the edge of a second molten pool forming a keyhole and a beam of the molten pool, so that liquid bridge transition can be formed, and the welding stability can be improved;
in the welding method, the welding wire is melted by the first small-energy laser beam, the second laser beam forms a keyhole and a molten pool, and the impact of the molten pool filled with liquid metal on the keyhole can be obviously reduced due to the fact that the end of the welding wire is far away from the keyhole. The first laser beam is positioned at the edge of the molten pool formed by the second laser beam, so that the liquid metal formed by the welding wire melted by the first laser beam can continuously flow into the molten pool under the attraction action of the surface tension of the molten pool, and the liquid metal continuously flows into the molten pool along the edge of the molten pool to have minimum impact on the keyhole and the molten pool, thereby obviously improving the stability of the welding process, obviously reducing the number of process air holes and further improving the quality of the welding seam;
in the welding method, the heat input of the second laser beam forming the keyhole and the molten pool acting on the welding workpiece is small, so that the deformation of the welding workpiece can be obviously reduced, and the process can meet the harsh requirements of the welding seam quality of certain welding workpieces with high requirements on welding deformation precision in the industrial field; the first low-energy laser beam only has small heat influence on the welding workpiece by melting the welding wire, so that the heat input to the welding workpiece can be obviously reduced, the grain size of the welding seam structure is further refined, and the welding seam quality is improved.
Drawings
FIG. 1 is a schematic diagram of the working principle of the double-beam laser filler wire welding method for the T-shaped joint of the invention;
FIG. 2 is a schematic view showing the shape of a keyhole of a T-shaped joint in a state where keyholes on both sides of the conventional laser filler wire welding are through;
FIG. 3 is a keyhole shape in which the laser energy at both sides of the T-shaped joint is slightly lower than that in a through state;
FIG. 4 is a keyhole shape in which laser energy on both sides of the T-shaped joint is lower than that in a through state;
FIG. 5 is a schematic view showing the shape of a keyhole at a laser beam interval of 1mm on both sides of a conventional laser filler wire welding of a T-shaped joint;
FIG. 6 is a schematic view of the shape of a keyhole at a laser beam interval of 1.5mm on both sides of a conventional laser filler wire welding of a T-shaped joint;
FIG. 7 is a schematic diagram showing the comparison between the shape of a keyhole (b) in which an active agent (a) is previously placed and the shape of a keyhole in which no active agent is placed in the laser beam welding region of a T-shaped joint stud and a riser;
FIG. 8 is a longitudinal cross-sectional view of a weld seam of a conventional laser filler wire weld of a T-joint;
FIG. 9 is a longitudinal cross-sectional view of a weld joint of the present invention in a dual-beam laser filler wire welding of a T-joint;
the labels in the figure are: 1. the welding method comprises the following steps of a first side two laser beams, a second side two laser beams, a wire feeding pipe, a wire welding pipe, a welding wire, a keyhole, a welding pool, a welding seam, a base plate, a welding seam, a welding rib and a stud, wherein the welding wire is welded on the welding seam, and the welding seam is welded on the base plate and the stud.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
A double-beam laser wire-filling welding method for a T-shaped joint capable of reducing porosity of a welding seam specifically comprises the following steps:
s1, performing surface treatment on the stud and the base plate of the T-shaped joint before welding to remove impurities on the surface of the welded workpiece;
s2, fixing the T-shaped joint stud and the base plate on a welding fixture, reserving a certain gap (the gap size is 0.01mm-0.5 mm) between the T-shaped joint stud and the base plate, filling liquid metal into the gap through capillary action after pre-melting a welding wire by utilizing a small-energy laser beam along a welding direction, wherein the laser penetration effect is increased invisibly because the T-shaped joint reserves the certain gap, and the welding wire in front of the laser beam forming the keyhole is melted into a liquid state, so that the welding wire can flow into the gap for pre-filling and the energy absorption rate of a second laser beam forming the keyhole can be greatly improved, the mutually-communicated keyhole can be easily formed on two sides of the T-shaped joint, the quantity of bubbles in a molten pool is reduced, and the porosity of a welding seam is reduced;
s3, arranging a laser on each of two sides of the T-shaped joint, adjusting a light splitting module of the laser to enable the laser to split a first laser beam for melting a welding wire and a second laser beam meeting the requirement of melting a base material to form a keyhole, wherein the beam distance between the first laser beam split by the laser and the second laser beam is 0.5-1.3mm, the distance between the second laser beam split by the laser and the welding wire is-1-1 mm, and the laser is Nd: YAG laser, CO2A laser or a fiber laser. After the small-energy laser melts the welding wire, the liquid metal at the end of the welding wire is contacted with the edge of a second molten pool of the beam forming the keyhole and the molten pool, so that liquid bridge transition can be formed, and the welding stability can be improved. The welding wire is melted by the first small-energy laser beam, the second laser beam forms a keyhole and a molten pool, and the impact of the molten pool filled with liquid metal on the keyhole can be obviously reduced due to the fact that the end of the welding wire is far away from the keyhole. The first laser beam is at the edge of the molten pool formed by the second laser beam, so that the liquid metal formed by the welding wire melted by the first laser beam can continuously flow into the molten pool under the attraction action of the surface tension of the molten pool, and the impact of the liquid metal on the keyhole and the molten pool caused by the continuous flow of the liquid metal into the molten pool along the edge of the molten pool is minimum, thereby obviously improving the stability of the welding process, obviously reducing the number of process air holes and further improving the quality of the welding seam
And S4, adjusting the second laser beams emitted by the lasers on the two sides of the T-shaped joint to enable the light spots of the second laser beams on the two sides of the T-shaped joint to coincide. The distance between the laser beams of the keyhole formed by the second beams on the two sides of the T-shaped joint is zero, so that the stability of penetrating the keyhole can be improved, and the generation of welding bubbles caused by the fact that the keyhole on the two sides of the T-shaped joint cannot continuously form a penetrating keyhole in a molten pool is reduced.
And S5, presetting an active agent in advance in the welding area, starting a laser and a wire feeder, and simultaneously spraying a protective gas (the protective gas is argon or helium) above the molten pool to prevent the molten pool from being oxidized, so as to carry out the T-shaped joint double-beam laser wire filling welding.
To further illustrate the superiority of the welding method of the present invention, the welding results obtained by the different comparative welding examples are further illustrated. FIG. 2 is a schematic view showing the shape of a keyhole of a T-shaped joint in a state where keyholes on both sides of the conventional laser filler wire welding are through; FIG. 3 is a keyhole shape in which the laser energy at both sides of the T-shaped joint is slightly lower than that in a through state; FIG. 4 is a keyhole shape in which laser energy on both sides of the T-shaped joint is lower than that in a through state; FIG. 5 is a schematic view showing the shape of a keyhole at a laser beam interval of 1mm on both sides of a conventional laser filler wire welding of a T-shaped joint; FIG. 6 is a schematic view of the shape of a keyhole at a laser beam interval of 1.5mm on both sides of a conventional laser filler wire welding of a T-shaped joint; FIG. 7 is a schematic diagram showing the comparison between the shape of a keyhole (b) in which an active agent (a) is previously placed and the shape of a keyhole in which no active agent is placed in the laser beam welding region of a T-shaped joint stud and a riser; FIG. 8 is a longitudinal cross-sectional view of a weld seam of a conventional laser filler wire weld of a T-joint; FIG. 9 is a longitudinal cross-sectional view of a weld joint of the present invention for dual-beam laser filler wire welding of T-joints. From a comparison of the longitudinal cross sections of the weld seams of fig. 8 and 9, it can be seen that the number of weld seam blowholes of the longitudinal cross section of the weld seam of the double-beam laser filler wire welding of the T-shaped joint of the present invention is significantly lower than that of the conventional laser filler wire welding of the T-shaped joint.
As can be seen from fig. 2-9, when two keyholes are not penetrated, the keyholes on two sides are not completely connected together (shown in fig. 3 and 4), welding bubbles are easily generated, molten pool metal flow behavior is complex, and further, the escape of the welding bubbles is not facilitated, and when the welding bubbles do not escape from the molten pool before the molten pool is solidified, weld pores are generated, and the quality of the weld is affected.
When the two key holes are not penetrated, the key holes on the two sides are not completely associated, so that the welding bubbles are easy to generate, the metal flowing behavior of the molten pool is complex, the escape of the welding bubbles is not facilitated, and when the welding bubbles do not escape out of the molten pool before the molten pool is solidified, the welding bubbles are generated, so that the welding porosity of the welding seam is high.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.