CN103008896A - Composite welding method combining laser with friction stir welding - Google Patents

Abstract

The invention discloses a composite welding method that can achieve fast welding speed and high welding quality of stainless steel. The welding method applies laser and friction stir welding, a composite welding technology, to the efficient connection of welded plates with relatively hard materials such as stainless steel, and solves the problem of The problem of efficient connection of friction stir welding of hard material welded plates. The method mainly includes: on the stainless steel plate to be welded, the thickness of the stainless steel plate is between 20-50mm, the first laser beam is arranged on the back of the stainless steel plate, the second laser beam and the friction stirring head are arranged on the front of the stainless steel plate, along the In the direction opposite to the welding direction, the first laser beam, the first friction stirring head, the second friction stirring head, and the second laser beam are sequentially arranged; wherein the first friction stirring head and the second friction stirring head are respectively located on different sides of the stainless steel plate. side.

Description

A Hybrid Welding Method Combining Laser and Friction Stir Welding

technical field

The invention relates to the field of laser processing and manufacturing, in particular to a composite welding method combining laser and friction stir welding.

Background technique

Since the friction stir welding is a solid phase welding method that uses the high-speed rotating stirring head and the shaft shoulder and the metal to be in a plastic state. As the stirring head advances, the metal moves to the rear of the stirring head to form a solid-phase welding method, so it is suitable for The welding of softer metals has been successfully applied to the welding of non-ferrous metals such as Al and Cu, but at the same time, there are still disadvantages when friction stir welding harder metals such as stainless steel. Due to the high hardness of stainless steel, its welding speed is slow and its efficiency is low, which has become a shackle that restricts the wide application of friction stir welding of stainless steel; in addition, based on the characteristics of friction stir welding itself, there is a "keyhole" at the end of the welded parts. Therefore, when necessary, it is necessary to add "welding plate or welding plate" to the welding process, which is a waste of resources for the installation of welding equipment. In addition, there are researches, inventions and designs of special stirring heads or embedded friction stirring Welding method to reduce the probability of occurrence of such problems, Chinese published patent CN102120287A discloses a dissimilar metal embedded friction stir seam welding method, which specifically discloses processing one or more dovetail grooves on a harder second base material , and then assembled according to the overlapping form, it is required to place the aluminum plate on the upper side of the dovetail groove of the harder second base material; use a needleless stirring head and install it obliquely; start the stirring head to rotate and make it contact with the surface of the aluminum plate: limit the stirring head The pressing depth is between 0.1mm and 2mm, and there is no need to penetrate the welding interface; after a few seconds of friction and preheating at the starting end, the rotating stirring head or worktable can be moved to squeeze the aluminum plate into the groove of the lower plate In this friction welding method, the keyhole can be avoided, but the application range is narrow, and the workload before welding is large, and the welding efficiency is very low. Therefore, it is urgent to solve these two problems. At the same time, because laser welding has the characteristics of high power density, low welding heat input, small welding heat-affected zone and small welding deformation, it is widely used in the field of stainless steel welding, but laser welding has high requirements for clamping accuracy, which also restricts The development of laser welding of stainless steel.

Due to the influence of the size of the stirring head during friction stir welding, each type of stirring head has a maximum processing size, which also restricts its welding thickness, and cannot complete the processing of plates exceeding its maximum processing size .

Contents of the invention

In order to solve the problems existing in the welding of welding plates with relatively hard materials in the background technology, this invention provides a composite welding method that can realize fast welding speed and high welding quality of welding plates. This welding method successfully combines laser and dual Stir head friction welding, a composite welding technology, is applied to the efficient connection of welded plates, which solves the problem of efficient connection of large thickness welded plates by friction stir welding.

In order to solve the above problems, the present invention proposes a composite welding method of laser welding and friction stir welding, which includes: arranging a first friction stirring head on the front of the plate to be welded, and arranging a first laser beam on the back of the plate to be welded; During welding, the first laser beam is used to irradiate and soften the part to be welded on the plate to be welded, and then the first friction stirring head is used to perform friction stir welding.

Wherein, a second friction stirring head is arranged on the back of the plate to be welded, and a second laser beam is arranged on the front of the plate to be welded; the first laser beam, the first friction stirring head, the second friction stirring head The head and the second laser beam are arranged sequentially along the direction opposite to the welding direction; the action points of the first friction stirring head and the second friction stirring head on the surface of the plate to be welded are separated by a certain distance in the horizontal direction; during welding, The first laser beam softens the part to be welded, the first friction stirring head and the second friction stirring head perform friction welding on the front and back sides of the plate to be welded simultaneously, and the second laser beam Seam for redissolution.

The plate to be welded is a stainless steel plate.

By adding another friction stirring head on the back of the stainless steel plate, the thickness of the stainless steel plate that can be welded by the welding method can be greatly improved, and the first laser beam is preheated in advance along the welding direction and initially softens the stainless steel plate to be welded, which can Significantly improve the welding speed of friction stir welding; the second laser beam can remelt the weld seam that has been welded by friction stir welding, on the one hand, it can improve the appearance of the weld seam completed by friction stir welding, and eliminate The keyhole left; on the other hand, the quality of the weld can be further improved. Reasonably select the appropriate power of the first laser beam and the second laser beam according to the thickness of the plate. When welding starts, the first laser beam first acts on the stainless steel plate to be welded, and then the first friction stirring head, the second friction stirring head, The second laser beam acts on the stainless steel plate to be welded in turn; when the welding is over, the first laser beam leaves the stainless steel plate to be welded first, and then the first friction stirring head, the second friction stirring head, and the second laser beam leave the stainless steel plate to be welded in turn board. The whole welding process does not require soldering plate or soldering plate. Through the laser beam + double stirring head friction stir welding composite welding method, the effect of 1+1>2 is achieved, so that the welding of stainless steel can achieve fast and good welding.

Description of drawings

Fig. 1 is a schematic diagram of assembly of a composite welded stainless steel plate by laser welding and friction stir welding in a preferred embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

As shown in Figure 1, the present invention proposes a hybrid welding method combining laser and friction stir welding. The method includes: on the plate to be welded 1, sequentially arrange the first laser beam 3, the first friction stirring head 2, the second friction stirring head 5, and the second laser beam 4 along the direction opposite to the welding direction; One laser beam and the second friction stirring head are arranged on the back of the plate to be welded, the second laser beam and the first friction stirring head are arranged on the front of the plate to be welded, and the first friction stirring head and the second friction stirring head are arranged on the plate to be welded The action points on the surface are separated by a certain distance in the horizontal direction; the first laser beam can be derived from a CO2 laser, and the angle between the center line of the first laser beam and the vertical direction of the upper surface of the plate to be welded is α, wherein , 15°≤α≤30°, the laser power of the first laser beam is P1, wherein 1200w≤P1≤2000w, adjust the position of the focus of the laser beam relative to the surface of the plate to be welded, so that the welder irradiated on the plate to be welded The diameter of the laser spot on the piece is 2-5mm; the second laser beam can originate from a CO2 laser, the centerline of the second laser beam is perpendicular to the surface of the stainless steel plate, and the laser power of the second laser beam is P2, wherein 3000w≤P2≤6000w; the included angle between the center line of the first friction stirring head and the second friction stirring head and the vertical direction of the upper surface of the plate to be welded is θ, wherein 0°<θ≤2° ; No welding plate or welding plate is needed in the welding process, and the welding speeds of the first laser beam, the first friction stirring head, the second friction stirring head and the second laser beam are the same, which are 1.5-3m/min. The point of action of the first laser beam on the surface of the plate to be welded is 3-6 cm away from the point of action of the first friction stirring head on the surface of the plate to be welded. The horizontal distance of the point of action on the surface of the welding plate is 3-6cm, and the horizontal distance of the point of action of the second laser beam on the surface of the plate to be welded is 8-18cm from the point of action of the second friction stirring head on the surface of the plate to be welded , wherein the plate to be welded can be a hard stainless steel plate, and the thickness of the stainless steel plate is less than or equal to 50mm.

The above-mentioned consistent welding method proposed by the present invention is especially suitable for welding thicker welding plates, such as stainless steel plates. The welding process is as follows: after the welding seam is softened by using the first laser beam to irradiate the welding plate, the first friction stirring head and the second friction stirring head The stirring head performs stirring welding on the front and back sides of the welding plate at the same time, and after the welding is completed, the second laser beam remelts the welding seam to make the welding seam smoother.

It can be seen that the above-mentioned composite welding method proposed by the present invention can greatly increase the thickness of the welded plate that can be welded by the welding method by adding a second friction stirring head on the back of the welded plate. By arranging the first laser beam on the back of the welded plate , can prevent the first friction stirring head from hindering the injection of the first laser beam, and can effectively reduce the level of the action point of the first laser beam on the surface of the stainless steel plate and the action point of the friction stirring head on the surface of the stainless steel plate In this way, friction stir welding can be performed immediately after the first laser beam irradiates the stainless steel to soften, which greatly improves the production efficiency; by adjusting the position of the focus of the first laser beam relative to the surface of the welding plate to be welded, a large spot is irradiated on the surface of the welding plate In this way, the welding plate can be heated and softened evenly on a large area. Since the contact area between the friction stir head and the welding plate is large, the welding plate can be irradiated with a large spot, so that in the subsequent friction stir welding process, the stirring head The contact with the softened and uniform welding plate makes the effect of friction stir welding significantly improved, and the surface of the weld seam after welding is more beautiful; the oblique incidence of the first laser beam can also increase the irradiation area of the first laser beam to a certain extent; Both the first laser beam and the second laser beam are produced by CO2 laser, which can make full use of the mechanism of CO2 laser wavelength and stainless steel, so that the stainless steel plate has a good softening effect and greatly saves costs.

Several specific implementations of the above-mentioned composite welding method proposed by the present invention are given below.

Embodiment (1)

When the thickness of the stainless steel plate 1 to be welded is 30 mm, the first laser beam 3, the first friction stirring head 2, the second friction stirring head 5, and the second laser beam 4 are sequentially arranged along the direction opposite to the welding direction; The beam 3 and the second friction stirring head 5 are arranged on the back of the stainless steel plate, and the second laser beam 4 and the first friction stirring head 2 are arranged on the front of the stainless steel plate; the first laser beam 3 originates from a CO2 laser, and the first laser beam The angle between the centerline of the beam 3 and the vertical direction on the surface of the stainless steel plate is α=15°, the laser power of the first laser beam is P1=1200w, and the focal point of the first laser beam is adjusted relative to the surface of the stainless steel plate to be welded The position that makes the diameter of the laser spot radiated on the stainless steel plate to be welded is 3.5mm; the second laser beam 4 originates from a CO2 laser, and the center line of the second laser beam is perpendicular to the surface of the stainless steel plate, The laser power of the second laser beam is P2=3000w; the first friction stirring head is arranged on the front of the stainless steel plate, the second friction stirring head is arranged on the back of the stainless steel plate, the first friction stirring head, the second friction stirring head The included angle between the centerline of the head and the vertical direction on the surface of the stainless steel plate is θ=2°; The distance is 4cm, the horizontal distance of the action point of the first friction stirring head and the second friction stirring head on the surface of the stainless steel plate is 3cm, and the action point of the second laser beam on the surface of the stainless steel plate is the same as that of the second friction stirring head. The action point distance of the head on the surface of the stainless steel plate is 12cm; during the welding process, there is no need for a welding plate or a welding plate, and the welding speed of the first laser beam, the first friction stirring head, the second friction stirring head, and the second laser beam The same, both are 1.5m/min. The tensile strength of the welding zone of the welded stainless steel plate is higher than that of the base material of the stainless steel plate.

Embodiment (two)

When the thickness of the stainless steel plate 1 to be welded is 40 mm, the first laser beam 3, the first friction stirring head 2, the second friction stirring head 5, and the second laser beam 4 are sequentially arranged along the direction opposite to the welding direction; A laser beam 3 originates from a CO2 laser, the angle between the center line of the first laser beam 3 and the vertical direction on the surface of the stainless steel plate is α=30°, and the laser power of the first laser beam is P1=1600w, Adjust the position of the focus of the laser beam relative to the surface of the stainless steel plate to be welded so that the diameter of the laser spot radiated on the workpiece to be welded is 5mm; the second laser beam 4 originates from a CO2 laser, and the center of the second laser beam The line is perpendicular to the surface of the stainless steel plate, the laser power of the second laser beam is P2=4500w; the first friction stirring head is arranged on the front of the stainless steel plate, the second friction stirring head is arranged on the back of the stainless steel plate, the first The included angle between the center line of the friction stirring head and the second friction stirring head and the vertical direction on the surface of the stainless steel plate is θ=0.5°; The action point distance on the surface of the stainless steel plate is 5cm, the horizontal distance of the action point of the first friction stirring head and the second friction stirring head on the surface of the stainless steel plate is 5cm, and the distance of the second laser beam on the surface of the stainless steel plate is 5cm. The distance between the point of action and the point of action of the second friction stirring head on the surface of the stainless steel plate is 15cm; during the welding process, there is no need for a welding plate or a welding plate, the first laser beam, the first friction stirring head, the second friction stirring head, The welding speed of the second laser beam is the same, both are 3m/min. The tensile strength of the welding zone of the welded stainless steel plate is higher than that of the base material of the stainless steel plate.

Embodiment (three)

When the thickness of the stainless steel plate 1 to be welded is 50 mm, the first laser beam 3, the first friction stirring head 2, the second friction stirring head 5, and the second laser beam 4 are sequentially arranged along the direction opposite to the welding direction; Laser beam 3 originates from CO2 laser, the angle between the center line of the first laser beam 3 and the vertical direction on the surface of the stainless steel plate is α=22 °, and the laser power of the first laser beam is P1=2000w, adjusted The position of the focus of the laser beam relative to the surface of the stainless steel plate to be welded makes the diameter of the laser spot radiated on the workpiece to be welded at 3mm; the second laser beam 4 originates from a CO2 laser, and the center line of the second laser beam Vertical to the surface of the stainless steel plate, the laser power of the second laser beam is P2=6000w; the first friction stirring head is arranged on the front of the stainless steel plate, the second friction stirring head is arranged on the back of the stainless steel plate, the first friction The included angle between the center line of the stirring head and the second friction stirring head and the vertical direction on the surface of the stainless steel plate is θ=1°; the point of action of the first laser beam on the surface of the stainless steel plate is within The action point distance on the surface of the stainless steel plate is 4cm, the horizontal distance of the action point of the first friction stirring head and the second friction stirring head on the surface of the stainless steel plate is 6cm, and the effect of the second laser beam on the surface of the stainless steel plate The action point distance between the point and the second friction stirring head on the surface of the stainless steel plate is 18cm; during the welding process, there is no need for a welding plate or a welding plate, the first laser beam, the first friction stirring head, the second friction stirring head, the second The welding speed of the two laser beams is the same, both are 2m/min. The tensile strength of the welding zone of the welded stainless steel plate is higher than that of the base material of the stainless steel plate.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. A compound welding method of laser welding and friction stir welding, which comprises: arranging the first friction stirring head on the front of the plate to be welded, and arranging the first laser beam on the back side of the plate to be welded; during welding, at first by the first The laser beam irradiates and softens the part to be welded on the plate to be welded, and then performs friction stir welding by the first friction stirring head. 2. The method according to claim 1, wherein a second friction stirring head is also arranged on the back side of the plate to be welded, and a second laser beam is arranged on the front side of the plate to be welded; the first The laser beam, the first friction stirring head, the second friction stirring head and the second laser beam are arranged in sequence along the direction opposite to the welding direction; the effect of the first friction stirring head and the second friction stirring head on the surface of the plate to be welded The points are separated by a certain distance in the horizontal direction; during welding, the first laser beam softens the part to be welded, and the first friction stirring head and the second friction stirring head perform friction welding on both sides of the plate to be welded simultaneously , after the welding is completed, the second laser beam remelts the welding seam. 3. The method according to claim 2, wherein the plate to be welded is a stainless steel plate with a thickness less than or equal to 50 mm. 4. method as claimed in claim 3, it is characterized in that, described first laser beam and second laser beam all originate from CO2 laser device, the center line of described first laser beam is the same as the vertical direction of plate surface to be welded The included angle is α, wherein, 15°≤α≤30°, the laser power of the first laser beam is P1, wherein 1200w≤P1≤2000w, the diameter of the laser spot irradiated by the first laser beam on the plate to be welded 3-5mm; the center line of the second laser beam is perpendicular to the surface of the stainless steel plate, and the laser power of the second laser beam is P2, wherein 3000w≤P2≤6000w. 5. The method according to claim 3, wherein the angle between the center line of the first friction stirring head and the second friction stirring head and the vertical direction of the upper surface of the plate to be welded is θ, wherein 0.5° <θ≤2°. 6. The method according to claim 3, wherein the welding speeds of the first laser beam, the first friction stirring head, the second friction stirring head, and the second laser beam are the same, all being 1.5-3m/min , the horizontal distance between the point of action of the first laser beam on the surface of the plate to be welded and the point of action of the first friction stirring head on the surface of the plate to be welded is 4-5cm, the first friction stirring head and the second stirring The horizontal distance of the point of action of the friction head on the surface of the plate to be welded is 3-6 cm, the horizontal distance between the point of action of the second laser beam on the surface of the plate to be welded and the point of action of the second friction stirring head on the surface of the plate to be welded It is 12-18cm. 7. method as claimed in claim 3, is characterized in that, the thickness of described stainless steel plate is 30mm; The included angle of the center line of described first laser beam with the vertical direction of stainless steel plate surface is α=15 °, so The laser power of the first laser beam is P1=1200w, the diameter of the laser spot irradiated by the laser beam on the stainless steel plate is 3.5mm, and the laser power of the second laser beam is P2=3000w; the first friction stir The included angle between the center line of the head and the second friction stirring head and the vertical direction of the surface of the stainless steel plate is θ=2°; The distance of the point of action on the surface is 4cm; the horizontal distance of the point of action of the first friction stirring head and the second friction stirring head on the surface of the stainless steel plate is 3cm, and the point of action of the second laser beam on the surface of the stainless steel plate The action point distance with the second friction stirring head on the stainless steel plate surface is 12cm, and the welding speeds of the first laser beam, the first friction stirring head, the second friction stirring head and the second laser beam are the same, all being 1.5m /min. 8. method as claimed in claim 3 is characterized in that, the thickness of described stainless steel plate is 40mm; The included angle of the center line of described first laser beam with the vertical direction of stainless steel plate surface is α=30 °, so The laser power of the first laser beam is P1=1600w, the diameter of the laser spot irradiated by the laser beam on the stainless steel plate is 5mm, and the laser power of the second laser beam is P2=4500w; the first friction stirring head The included angle between the center line of the second friction stirring head and the vertical direction of the surface of the stainless steel plate is θ=0.5°; The distance of the action point on the surface of the stainless steel plate is 5cm; the horizontal distance of the action point of the first friction stirring head and the second friction stirring head on the surface of the stainless steel plate is 5cm, and the action point of the second laser beam on the surface of the stainless steel plate is the same as The action point distance of the second friction stirring head on the stainless steel plate surface is 15cm, and the welding speeds of the first laser beam, the first friction stirring head, the second friction stirring head and the second laser beam are the same, all being 3m/min . 9. method as claimed in claim 3 is characterized in that, the thickness of described stainless steel plate is 50mm; The included angle of the center line of described first laser beam with the vertical direction of stainless steel plate surface is α=22 °, so The laser power of the first laser beam is P1=2000w, the diameter of the laser spot irradiated by the laser beam on the stainless steel plate is 3mm, and the laser power of the second laser beam is P2=6000w; the first friction stirring head The included angle between the center line of the second friction stirring head and the vertical direction of the surface of the stainless steel plate is θ=1°; The distance of the action point on the surface of the stainless steel plate is 4cm; the horizontal distance of the action point of the first friction stirring head and the second friction stirring head on the surface of the stainless steel plate is 6cm, and the action point of the second laser beam on the surface of the stainless steel plate is the same as The action point distance of the second friction stirring head on the stainless steel plate surface is 18cm, and the welding speeds of the first laser beam, the first friction stirring head, the second friction stirring head and the second laser beam are the same, all being 2m/min .

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