Multiple combined machining method integrating laser cutting blanking, groove machining and combined welding

Abstract

The invention discloses a multiple composite processing method integrating laser cutting blanking, groove processing and composite welding, which comprises the following steps of: firstly, quickly blanking a medium-thickness plate test piece by adopting a laser cutting mode, and cutting a semicircular groove at a to-be-welded part of a medium-thickness plate while blanking; clamping the medium-thickness plate test piece, and carrying out positioned welding by utilizing laser and MAG (Metal Active Gas Welding) hybrid welding; and finally, carrying out laser-electric arc hybrid welding on the medium-thickness plate test piece by adopting a single-side welding and double-side forming method. According to the invention, a processing mode of integrating blanking and groove processing is realized, the production efficiency can be improved, meanwhile, the size of a medium-thickness plate test piece and the size of an assembly gap can be accurately controlled, the consistency of the groove gap is ensured, the assembly time is shortened, the assembly efficiency is improved, and the production cost is reduced. Meanwhile, due to the semicircular groove, the change of the size of an assembly gap caused by welding deformation in the welding process can be prevented, the penetrating power of a laser key hole is improved, and high-quality, high-efficiency and low-cost combined machining is achieved.

Description

Technical Field

[0001] This invention relates to the field of composite welding processing technology for plates, specifically to a high-quality, high-efficiency welding method suitable for medium and heavy plates, and in particular to a multi-component composite processing method that integrates laser cutting, specific beveling, and laser-MAG composite welding. Background Technology

[0002] In the manufacturing of major equipment such as energy equipment, shipbuilding, petrochemicals, marine engineering, and aerospace, welding of thick-walled components is frequently encountered. Traditional welding faces challenges such as difficulty in heat input control, large welding deformation, and low production efficiency. In recent years, with the emergence and development of high-power lasers, laser deep penetration welding technology has been further applied in the welding and manufacturing of medium and thick plates in large-scale projects such as aerospace, shipbuilding, and nuclear power. Since single-laser welding of medium and thick plates easily produces deep surface depressions, laser-arc hybrid welding technology is often used. However, laser-arc hybrid welding of medium and thick plates is prone to various welding defects such as spatter, surface collapse, and bottom hump. In particular, the bottom hump defect is a key issue restricting the development and application of laser-arc hybrid welding technology, especially in the welding of medium and thick plates. Therefore, when the plate thickness exceeds 10mm, double-sided welding or beveling is mostly used to ensure welding quality. This results in low welding production efficiency and limited welding positions. In particular, it is difficult or impossible to flip large, thick-walled components. Therefore, adjusting the process to make single-sided welding and double-sided forming more advantageous for laser-arc composite welding of medium and thick plates is more important.

[0003] However, laser-arc hybrid welding of medium and thick plates currently faces a series of problems when using single-sided welding for double-sided forming. The primary challenge lies in the precise control and consistency of the assembly gap. To achieve good back-side forming, extremely precise assembly gaps (usually on the order of a few tenths of a millimeter) are required. Traditional methods use gapless or narrow-gap assembly, but gapless assembly easily leads to incomplete penetration or burn-through, which is more likely to occur with thicker plates, making it difficult to ensure welding quality. Narrow gaps, on the other hand, place extremely stringent requirements on assembly precision. Moreover, during the thermal cycling process of clamping, tack welding, and formal welding, the workpiece inevitably undergoes thermal expansion and contraction deformation, causing uncontrollable fluctuations in the preset micro-gap, which in turn leads to a series of defects such as weld bottom hump, undercut, lack of fusion, and uneven forming. The tolerance of welding quality for assembly gaps is extremely low, resulting in poor process stability and difficulty in guaranteeing yield. Therefore, maintaining the precise dimensions of the reserved assembly gap and the uniformity and consistency during welding are both extremely challenging.

[0004] Secondly, traditional beveling preparation methods are inefficient and costly. For welding medium and thick plates that require beveling, the process of separating the material preparation and machining (mechanical cutting, milling, planing) is usually adopted. This method has a long production cycle and requires a large investment in equipment. It is not only time-consuming and labor-intensive, but also extremely costly. Moreover, it is almost impossible to process a sawtooth-shaped bevel for some large or complex structural parts. At the same time, it is also difficult for a dedicated beveling machine to process a sawtooth-shaped bevel.

[0005] Therefore, how to develop an efficient beveling preparation method that can provide the necessary gap while actively suppressing gap changes during the welding process and optimizing the interaction environment between laser and electric arc is a technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0006] To address the challenges of controlling assembly gaps and ensuring consistent welding quality in single-sided welding with double-sided forming of medium-thick plates, this invention provides a multi-functional composite processing method integrating laser cutting, beveling, and composite welding. This method achieves integrated cutting and beveling, improving production efficiency. Simultaneously, it precisely controls the dimensions of the medium-thick plate specimen and the assembly gap, ensuring consistent bevel gaps, reducing assembly time, and increasing assembly efficiency. Furthermore, the semi-circular bevel prevents variations in assembly gap size due to welding deformation and enhances the penetration capability of the laser keyhole. This multi-functional composite processing method effectively guarantees the welding quality of single-sided welding with double-sided forming in laser + MAG composite welding of medium-thick plates (good weld formation on both sides and no hump defects at the bottom).

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a multi-functional composite processing method integrating laser cutting, beveling, and composite welding, comprising the following steps: S1. A laser cutting system is used to cut medium-thick plates. During the cutting process, a continuous bevel with a semi-circular cross-section is cut simultaneously and quickly at the edge of the plate to be welded, realizing an integrated processing mode of cutting and beveling. S2. Clean the bevel and adjacent areas of the plate to remove the oxide layer and cutting residue. Specifically, tools such as wire brushes and angle grinders can be used to clean the bevel and surrounding areas of the medium-thick plate specimen. S3. Place the two plates to be welded with their beveled edges facing each other, and clamp them together so that the bevels on the two plates are aligned and the mating surfaces are tightly fitted. Clean the area to be welded with anhydrous ethanol before and after clamping. S4. Use laser-MAG composite welding process to perform positioning spot welding on the clamped plates; S5. Using laser-MAG composite welding process, single-sided welding and double-sided forming welding are performed on the joints of the plates after positioning electric welding.

[0008] In step S1, the present invention creatively chooses to simultaneously and rapidly laser-cut a continuous, semi-circular bevel at the edge of the plate to be welded, instead of laser-cutting a V-shaped or other shaped bevel, such as a V-shaped bevel. This is because the power of laser cutting thick plates is relatively high, which would cause more burn damage to the tip of the V-shape, narrowing the gap between the bevels and increasing the contact area, which would seriously affect the welding effect. Although laser cutting to form a semi-circular bevel will also cause some burn damage, compared with cutting a V-shaped bevel, the change in the gap between the bevels is relatively small and the contact area is relatively small, thus ensuring a better welding effect.

[0009] Furthermore, in step S1, the medium-thick plate specimen is a carbon steel plate with a thickness ranging from 10 to 16 mm.

[0010] Furthermore, in step S1, the geometric parameters of the continuous semi-circular bevel satisfy the following: the radius R of the semi-circle is 0.6 to 0.9 mm, the depth H of the semi-circle is 0.4 to 0.6 mm, and the horizontal distance S between the centers of adjacent semi-circles is 0.1 to 0.15 mm.

[0011] By controlling the dimensions of the continuous semi-circular bevel within the above range, the required precise gap size and uniformity of the gap are achieved when welding carbon steel plates with a thickness range of 10 to 16 mm to obtain a qualified welded joint.

[0012] Furthermore, in step S1, the laser cutting process parameters are as follows: cutting power of 30-60kW, cutting speed of 10-18m / min, focal position of -2--3mm, protective gas of 10%CO2+90%Ar, and gas pressure of 6-7Bar.

[0013] Furthermore, in step S3, the medium-thick plate is rigidly clamped using tooling fixtures, and the horizontal distance S between adjacent semicircles of the bevel corresponds to each other.

[0014] Furthermore, in step S4, the spot welding process parameters are as follows: laser power is 3-5kW, defocusing amount is -2--4mm, laser deflection angle is 5°, welding wire diameter is 1.2mm, welding speed is 1.0-1.5m / min, wire feed speed is 6-8m / min, welding current is 200-234A, shielding gas is 10%CO2+90%Ar, gas flow rate is 15-20 L / min, and wire spacing is 2-3mm.

[0015] Spot welding is mainly used to secure the test piece before welding. The parameter settings are suitable for spot welding of carbon steel plates with a thickness of 16-20mm. It is necessary to ensure that the spot weld is firm, but it is not required to penetrate the test piece and form a large spot weld, so as to avoid affecting the subsequent welding process.

[0016] Furthermore, in step S5, the welding process parameters are as follows: laser power is 7-11kW, welding speed is 1.8-2.0m / min, defocusing amount is -2 to -4mm, welding wire diameter is 1.2mm, wire feed speed is 11.5-17.5m / min, welding current is 322-439A, shielding gas is 10%CO2+90%Ar, gas flow rate is 15-20 L / min, and wire spacing is 2-3mm.

[0017] The welding process parameter setting range is designed to meet the welding requirements of carbon steel plates with a thickness range of 10 to 16 mm. Within the parameter setting range of the semi-circular bevel, qualified welded joints can be obtained by single-sided welding and double-sided forming welding.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) In this invention, laser cutting is used to quickly cut the medium-thick plate specimen and at the same time, a bevel with a semi-circular shape is quickly cut at the welding point of the medium-thick plate specimen. This realizes the integrated processing mode of cutting and beveling. Compared with the method of cutting first and then machining to process a sawtooth-shaped bevel, it can not only greatly improve productivity and reduce costs, but also realize the beveling of complex structural parts.

[0019] (2) By controlling the values ​​of the semicircular radius R, the semicircular recess depth H, the horizontal distance S between adjacent semicircles, and the laser cutting process parameters, the required pre-reserved assembly gap size can be cut quickly and accurately, greatly reducing the impact of changes in the assembly gap size on the welding quality. During assembly, ensure that the horizontal distance S between adjacent semicircles at the bevels of the two test pieces corresponds and they are in contact with each other. This will better resist the deformation of the bevel caused by thermal expansion and contraction due to welding heat energy during the positioning spot welding and welding process, thus ensuring the uniformity of the assembly gap throughout the welding process.

[0020] (3) There is no need to measure the bevel gap during the assembly process; simply clamping is sufficient, which greatly improves the assembly efficiency and has significant value for improving actual production efficiency.

[0021] (4) Compared with narrow gaps, this gap with a semi-circular bevel can better limit the lateral dissipation of laser energy, which is conducive to the laser beam reflecting back and forth in the gap with a semi-circular bevel, further improving the keyhole penetration depth and further enhancing the stability of the bottom of the molten pool, thereby greatly reducing the probability of porosity and bottom hump.

[0022] (5) The assembly gap size with a semi-circular bevel provided by the integrated processing of blanking and beveling is more likely to obtain a high-quality welded joint (good formation on both sides of the weld and no hump defect at the bottom) under the condition of single-sided welding and double-sided forming welding of laser-MAG composite welding, compared with narrow gap or no gap. Attached Figure Description

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0024] Figure 1 This is a schematic diagram of the bevel with a semi-circular shape formed by laser cutting in Example 1; Figure 2 Metallographic image of the welded joint in Example 1; Figure 3 Metallographic image of the welded joint in Example 2; Figure 4 The image shows the metallographic diagram of the welded joint in Example 3. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1 This embodiment provides a multi-composite processing method for medium-thick steel plates, and the specific process flow is as follows: Select a 12mm thick Q235 steel plate and use laser cutting to quickly cut the Q235 steel plate into blanks. Simultaneously, cut a semi-circular bevel at the welding area of ​​the steel plate (see attached image). Figure 1 The laser cutting process parameters and the semi-circular bevel values ​​are shown in Table 1. A 12mm thick Q235 steel plate specimen was obtained by using 10% CO2 + 90% Ar as the cutting gas.

[0027] Table 1 Cutting process parameters and semi-circular bevel values Cutting speed (m / min) Cutting power (W) Cutting air pressure (bar) Defocusing amount (mm) The radius R (mm) of the semicircle Depth of the semi-circular concavity (H) Horizontal distance S (mm) between adjacent semicircles 17 40000 7 -2 0.6 0.4 0.1 Then, use tools such as wire brushes and angle grinders to clean the bevel and surrounding area of ​​the 12mm thick Q235 steel plate specimen, removing oxide film, cutting residue, etc.

[0028] Next, the test plates are clamped using tooling fixtures to ensure that the horizontal distance S between the adjacent semicircles of the two test pieces corresponds. Before and after clamping, the bevel and surrounding area are cleaned with anhydrous ethanol.

[0029] After clamping, the 12mm thick Q235 steel plate specimen was first tack welded using laser-MAG composite welding. The welding wire diameter was 1.2mm, the shielding gas was 10%CO2+90%Ar, the laser deflection angle was 5°, and other tack welding process parameters are shown in Table 2.

[0030] Table 2. Spot welding process parameters Laser power (W) Welding speed (m / min) Defocusing amount (mm) Wire feeding speed (m / min) Welding current (A) Gas flow rate (L / min) filament spacing (mm) 4000 1.2 -2 6 200 15 2 The 12mm thick Q235 steel plate specimen was then subjected to laser-MAG hybrid welding using a single-sided welding and double-sided forming method. The welding wire diameter was 1.2mm, the shielding gas was 10%CO2+90%Ar, the laser deflection angle was 5°, and other welding process parameters are shown in Table 3.

[0031] Table 3 Single-sided welding double-sided forming welding process parameters Laser power (W) Welding speed (m / min) Defocusing amount (mm) Wire feeding speed (m / min) Welding current (A) Gas flow rate (L / min) filament spacing (mm) 8200 1.8 -2 13 340 20 3 Example 2 This embodiment provides a multi-composite processing method for medium-thick steel plates, and the specific process flow is as follows: A 14mm thick Q235 steel plate was selected and laser cutting was used to quickly cut the Q235 steel plate. At the same time as cutting, a semi-circular bevel was quickly cut at the welding point of the steel plate to obtain a 14mm thick Q235 steel plate specimen. The cutting gas was 10% CO2 + 90% Ar. The laser cutting process parameters and semi-circular bevel values ​​are shown in Table 4.

[0032] Table 4 Cutting process parameters and semi-circular bevel values Cutting speed (m / min) Cutting power (W) Cutting air pressure (bar) Defocusing amount (mm) The radius R (mm) of the semicircle Depth of the semi-circular concavity (H) Horizontal distance S (mm) between adjacent semicircles 15 60000 7 -2 0.7 0.5 0.12 Then, use tools such as wire brushes and angle grinders to clean the bevel and surrounding area of ​​the 14mm thick Q235 steel plate specimen, removing oxide film, cutting residue, etc.

[0033] Next, the test plates are clamped using tooling fixtures to ensure that the horizontal distance S between the adjacent semicircles of the two test pieces corresponds. Before and after clamping, the bevel and surrounding area are cleaned with anhydrous ethanol.

[0034] After clamping, the 14mm thick Q235 steel plate specimen was first tack welded using laser-MAG composite welding. The welding wire diameter was 1.2mm, the shielding gas was 10%CO2+90%Ar, the laser deflection angle was 5°, and other tack welding process parameters are shown in Table 5.

[0035] Table 5. Positioning spot welding process parameters Laser power (W) Welding speed (m / min) Defocusing amount (mm) Wire feeding speed (m / min) Welding current (A) Gas flow rate (L / min) filament spacing (mm) 4200 1.2 -2 6 200 15 2 The 14mm thick Q235 steel plate specimen was then subjected to laser-MAG hybrid welding using a single-sided welding and double-sided forming method. The welding wire diameter was 1.2mm, the shielding gas was 10%CO2+90%Ar, the laser deflection angle was 5°, and other welding process parameters are shown in Table 6.

[0036] Table 6 Single-sided welding double-sided forming welding process parameters Laser power (W) Welding speed (m / min) Defocusing amount (mm) Wire feeding speed (m / min) Welding current (A) Gas flow rate (L / min) filament spacing (mm) 10300 1.8 -2 17.5 439 20 3 Example 3 This embodiment provides a multi-composite processing method for medium-thick steel plates, and the specific process flow is as follows: A 16mm thick Q235 steel plate was selected and laser cutting was used to quickly cut the Q235 steel plate. At the same time as cutting, a semi-circular bevel was quickly cut at the welding point of the steel plate to obtain a 16mm thick Q235 steel plate specimen. The cutting gas was 10% CO2 + 90% Ar. The laser cutting process parameters and semi-circular bevel values ​​are shown in Table 7.

[0037] Table 7 Cutting process parameters and semi-circular bevel values Cutting speed (m / min) Cutting power (W) Cutting air pressure (bar) Defocusing amount (mm) The radius R (mm) of the semicircle Depth of the semi-circular concavity (H) Horizontal distance S (mm) between adjacent semicircles 13.5 60000 7 -2 0.9 0.6 0.15 Next, use tools such as wire brushes and angle grinders to clean the bevel and surrounding area of ​​the 16mm thick Q235 steel plate specimen, removing oxide film, cutting residue, etc.

[0038] Next, the test plate is clamped using tooling fixtures to ensure that the horizontal distance S between adjacent semicircles corresponds. Before and after clamping, the bevel and surrounding area are cleaned with anhydrous ethanol.

[0039] After clamping, the 16mm thick Q235 steel plate specimen was first tack welded using laser-MAG composite welding. The welding wire diameter was 1.2mm, the shielding gas was 10%CO2+90%Ar, the laser deflection angle was 5°, and other tack welding process parameters are shown in Table 8.

[0040] Table 8. Spot welding process parameters Laser power (W) Welding speed (m / min) Defocusing amount (mm) Wire feeding speed (m / min) Welding current (A) Gas flow rate (L / min) filament spacing (mm) 4500 1.2 -2 6 200 15 2 The 16mm thick Q235 steel plate specimen was then subjected to laser-MAG hybrid welding using a single-sided welding and double-sided forming method. The welding wire diameter was 1.2mm, the shielding gas was 10%CO2+90%Ar, the laser deflection angle was 5°, and other welding process parameters are shown in Table 9.

[0041] Table 9 Single-sided welding double-sided forming welding process parameters Laser power (W) Welding speed (m / min) Defocusing amount (mm) Wire feeding speed (m / min) Welding current (A) Gas flow rate (L / min) filament spacing (mm) 11000 1.8 -2 15 402 20 3 Comparative Example 1 Comparative Example 1 is a comparative test example of Example 1, and its difference from Example 1 is as follows: The 12mm thick Q235 steel plate was cut directly without cutting out a bevel with a semi-circular shape. The reserved assembly gap size was 0.6mm, which is similar to the assembly gap size with a semi-circular bevel in Example 1.

[0042] The other steps and parameter settings are the same as in Example 1.

[0043] Comparative Example 2 Comparative Example 2 is a comparative test example of Example 1, and its difference from Example 1 is as follows: The 12mm thick Q235 steel plate was cut directly without a beveled edge and without leaving any assembly gap.

[0044] The other steps and parameter settings are the same as in Example 1.

[0045] Comparative Example 3 Comparative Example 3 is a comparative test example of Example 1, and its difference from Example 1 is as follows: Only the parameter values ​​of the semi-circular bevel portion were changed, as shown in Table 10. In this comparative example, the parameter values ​​of each part of the semi-circular bevel are lower than the corresponding parameter values ​​in Example 1.

[0046] Table 10 Parameter values ​​for semi-circular bevels The radius R (mm) of the semicircle Depth of the semi-circular concavity (H) Horizontal distance S (mm) between adjacent semicircles 0.4 0.3 0.08 The other steps and parameter settings are the same as in Example 1.

[0047] Comparative Example 4 Comparative Example 4 is a comparative test example of Example 1, and its difference from Example 1 is as follows: Only the parameter values ​​of the semi-circular bevel portion were changed, as shown in Table 11. In this comparative example, the parameter values ​​of each part of the semi-circular bevel are higher than the corresponding parameter values ​​in Example 1.

[0048] Table 11 Parameter values ​​for semi-circular bevels The radius R (mm) of the semicircle Depth of the semi-circular concavity (H) Horizontal distance S (mm) between adjacent semicircles 1.0 0.7 0.18 The other steps and parameter settings are the same as in Example 1.

[0049] Comparative Example 5 Comparative Example 5 is a comparative test example of Example 2, and its difference from Example 2 is as follows: The 14mm thick Q235 steel plate was cut directly without cutting out a bevel with a semi-circular shape. The reserved assembly gap size was 0.7mm, which is similar to the assembly gap size with a semi-circular bevel in Example 2.

[0050] The other steps and parameter settings are the same as in Example 2.

[0051] Comparative Example 6 Comparative Example 6 is a comparative test example of Example 2, and its difference from Example 2 is as follows: The 14mm thick Q235 steel plate was cut directly without cutting a bevel with a semi-circular shape, and no assembly gap was reserved.

[0052] The other steps and parameter settings are the same as in Example 2.

[0053] Comparative Example 7 Comparative Example 7 is a comparative test example of Example 2, and its difference from Example 2 is as follows: Only the parameter values ​​of the semi-circular bevel portion were changed, as shown in Table 12. In this comparative example, the parameter values ​​of each part of the semi-circular bevel are lower than the corresponding parameter values ​​in Example 2.

[0054] Table 12 Parameter values ​​for semi-circular bevels The radius R (mm) of the semicircle Depth of the semi-circular concavity (H) Horizontal distance S (mm) between adjacent semicircles 0.5 0.3 0.09 The other steps and parameter settings are the same as in Example 2.

[0055] Comparative Example 8 Comparative Example 8 is a comparative test example of Example 2, and its difference from Example 2 is as follows: Only the parameter values ​​of the semi-circular bevel portion were changed, as shown in Table 13. In this comparative example, the parameter values ​​of each part of the semi-circular bevel are higher than the corresponding parameter values ​​in Example 2.

[0056] Table 13 Parameter values ​​for semi-circular bevels The radius R (mm) of the semicircle Depth of the semi-circular concavity (H) Horizontal distance S (mm) between adjacent semicircles 1.1 0.8 0.2 The other steps and parameter settings are the same as in Example 2.

[0057] Comparative Example 9 Comparative Example 9 is a comparative test example of Example 3, and its difference from Example 3 is as follows: The 16mm thick Q235 steel plate was cut directly without cutting out a bevel with a semi-circular shape. The reserved assembly gap size was 0.8mm, which is similar to the assembly gap size with a semi-circular bevel in Example 3.

[0058] The other steps and parameter settings are the same as in Example 3.

[0059] Comparative Example 10 Comparative Example 10 is a comparative test example of Example 3, and its difference from Example 3 is as follows: The 16mm thick Q235 steel plate was cut directly without cutting a bevel with a semi-circular shape, and no assembly gap was reserved.

[0060] The other steps and parameter settings are the same as in Example 3.

[0061] Comparative Example 11 Comparative Example 11 is a comparative test example of Example 3, and its difference from Example 3 is as follows: Only the parameter values ​​of the semi-circular bevel portion were changed, as shown in Table 14. In this comparative example, the parameter values ​​of each part of the semi-circular bevel are lower than the corresponding parameter values ​​in Example 3.

[0062] Table 14 Parameter values ​​for semi-circular bevels The radius R (mm) of the semicircle Depth of the semi-circular concavity (H) Horizontal distance S (mm) between adjacent semicircles 0.55 0.35 0.09 The other steps and parameter settings are the same as in Example 3.

[0063] Comparative Example 12 Comparative Example 12 is a comparative test example of Example 3, and its difference from Example 3 is as follows: Only the parameter values ​​of the semi-circular bevel portion were changed, as shown in Table 15. In this comparative example, the parameter values ​​of each part of the semi-circular bevel are higher than the corresponding parameter values ​​in Example 3.

[0064] Table 15 Parameter values ​​for semi-circular bevels The radius R (mm) of the semicircle Depth of the semi-circular concavity (H) Horizontal distance S (mm) between adjacent semicircles 1.2 0.8 0.2 The other steps and parameter settings are the same as in Example 3.

[0065] Experimental performance testing The welded joints of the welded specimens in Examples 1-3 and Comparative Examples 1-12 were observed to observe the surface forming effect of the weld (whether there were defects such as incomplete penetration, incomplete fusion, depression, undercut, and humps at the bottom of the weld). Metallographic analysis and mechanical property testing were performed only on the welded joints with better surface forming. At the same time, mechanical property testing was also performed on the base material, as shown in Tables 16 and 17.

[0066] Table 16 Welded joint sample type Average tensile strength / MPa Welding effect at welded joints Example 1 425 The weld surface is aesthetically pleasing, with good edge fusion and no obvious defects such as undercut, concavity, or bottom hump. The weld reinforcement on both sides is normal. Metallographic analysis confirms this. Figure 2 It can be seen that no obvious defects were found inside the weld. Example 2 412 Apart from some minor undercutting at certain locations on the weld face, no other obvious defects such as concavity or bottom hump were observed. The weld reinforcement on both sides was normal. Metallographic analysis confirmed this. Figure 3 It can be seen that no obvious defects were found inside the weld. Example 3 402 Apart from some slight undercut at the edge of the weld face, no other obvious defects such as concavity or bottom hump were observed. The weld reinforcement on both sides was normal. Metallographic analysis showed that... Figure 4 It can be seen that no obvious defects were found inside the weld. Comparative Example 1 / The weld front is uneven, with some areas raised and others sunken; the weld back shows discontinuous bottom humps and incomplete penetration in some areas. Comparative Example 2 / The weld front has good formation and uniform reinforcement, but the reinforcement is too high. However, the weld back is not fully penetrated. Comparative Example 3 / Poor fusion and unevenness were observed on the front side of the weld, while a small number of discontinuous humps appeared on the back side of the weld, and most areas were not fully penetrated. Comparative Example 4 / The weld front side shows collapse and poor fusion, while the weld back side shows intermittent, large humps. Comparative Example 5 / Discontinuous depressions appear on the front side of the weld, while discontinuous humps and incomplete penetration appear on the back side of the weld, with the two alternating. Comparative Example 6 / The weld front has good formation and uniform reinforcement, but the reinforcement is too high. However, the weld back is not fully penetrated. Comparative Example 7 / Poor fusion and unevenness were observed on the front side of the weld, while a small number of humps appeared on the back side of the weld, and most areas were not fully penetrated. Comparative Example 8 / The weld front side showed collapse and poor formation, while the weld back side showed discontinuous, large humps. Comparative Example 9 / The weld surface showed some bulges and some depressions, and the back of the weld showed discontinuous bottom hump and incomplete penetration. Comparative Example 10 / The weld front has good formation and uniform reinforcement, but the reinforcement is too high. However, the weld back is not fully penetrated. Comparative Example 11 / Poor fusion and unevenness were observed on the front side of the weld, while a small number of discontinuous humps appeared on the back side of the weld, and most areas were not fully penetrated. Comparative Example 12 / The weld front side showed collapse and poor formation, while the weld back side showed discontinuous, large humps. Example 1 441 -- Example 2 435 -- Example 3 429 -- Table 17 Base material sample type Average tensile strength / MPa Welding effect at welded joints Example 1 441 -- Example 2 435 -- Example 3 429 -- As shown in Tables 16 and 17, the tensile strength of the welded joints in Examples 1-3 all reached over 90% of the tensile strength of the base material. The overall weld surface was well-formed, with no obvious defects such as depressions or bottom humps except for some minor undercuts in certain locations. The weld reinforcement on both sides was also normal. Figure 2-4 It can be seen that no obvious defects were found inside the weld, thus confirming that the processing mode of laser blanking and beveling combined with laser-MAG composite welding is very effective for carbon steel plates with a thickness of 10-16mm when using single-sided welding and double-sided forming, and has achieved the expected results.

[0067] In Comparative Example 1, because a semi-circular bevel was not cut, although a 0.6mm assembly gap was also reserved compared to Example 1, the weld face showed an uneven surface, with some areas protruding and others sunken; the weld back showed discontinuous bottom humps and incomplete penetration in some areas, resulting in poor welding quality. The reasons for this are as follows: First, the assembly gap precision was not well controlled during the assembly process; second, the uniformity of the assembly gap was significantly reduced due to thermal deformation during tack welding and welding, resulting in gaps that were too large in some areas and too small in others. A gap that was too small would limit the effective range of the welding heat source, making it difficult for the laser beam to reach the bottom of the specimen, thus reducing the keyhole penetration ability and leading to incomplete penetration in some areas; while a gap that was too large would result in an excessively wide weld pool, causing the molten metal to collapse under gravity, forming pits on the weld face and bottom humps on the weld back.

[0068] In Comparative Example 2, compared to Example 1, no bevel with a semi-circular shape was cut, and no assembly gap was reserved. The weld front was well formed and the excess height was uniform, but the excess height was too high and the weld back was not fully penetrated, indicating that the laser lateral dissipation was serious and the keyhole penetration ability was reduced, resulting in some places not being fully penetrated.

[0069] Compared to Example 1, only the parameters of the semi-circular bevel were changed in Comparative Example 3. All parameter values ​​in Comparative Example 3 were lower than the corresponding parameter values ​​in Example 1, and also lower than the optimal parameter range for the semi-circular bevel. Poor fusion and unevenness were observed on the weld face, while a small number of humps appeared on the weld back, with most areas showing incomplete penetration. This was because the assembly gap formed by the semi-circular bevel was too small. This small gap limited the expansion of the welding heat source, making it difficult for the laser beam to reach the bottom of the specimen. Consequently, the laser keyhole was insufficient to penetrate the specimen, resulting in incomplete penetration on most of the weld back. The small number of bottom humps may have been caused by heat accumulation or instability in the welding process.

[0070] Compared to Example 1, only the parameters of the semi-circular bevel were changed in Comparative Example 4. All parameter values ​​in Comparative Example 4 were higher than the corresponding parameter values ​​in Example 1, and also higher than the optimal parameter range for the semi-circular bevel. The weld face showed collapse and poor fusion, while the weld back showed intermittent, large humps. This was because the assembly gap formed by the semi-circular bevel was too large. An excessively large gap leads to an excessively wide weld surface, causing the molten pool metal to easily collapse under gravity, forming deep pits and resulting in large humps at the bottom of the weld.

[0071] In Comparative Example 5, because a bevel with a semi-circular shape was not cut, although a 0.7mm assembly gap was also reserved compared to Example 2, discontinuous depressions appeared on the front of the weld, and discontinuous humps and incomplete penetration appeared on the back of the weld, with the two alternating. The reason is similar to that of Comparative Example 1.

[0072] Compared to Example 2, Comparative Example 6 did not cut a bevel with a semi-circular shape, nor did it leave an assembly gap. The weld front was well formed and the excess height was uniform, but the excess height was too high. However, the weld back was not fully penetrated, for reasons similar to Comparative Example 2.

[0073] Comparative Example 7, compared to Example 2, only changed the parameters of each part of the semi-circular bevel. The parameter values ​​of each part were lower than the corresponding parameter values ​​of Example 2, and also lower than the optimal parameter range of the semi-circular bevel. The weld front was poorly formed, showing an uneven surface, and a small number of bottom humps appeared on the back of the weld. Most areas were not fully penetrated. The cause of this was similar to that of Comparative Example 3.

[0074] Comparative Example 8, compared to Example 2, only changed the parameters of each part of the semi-circular bevel. The parameter values ​​of each part were higher than the corresponding parameter values ​​in Example 2, and also higher than the optimal parameter range for the semi-circular bevel. The weld face showed collapse and poor formation, while the weld back showed discontinuous, large bottom humps. The cause was similar to that of Comparative Example 4.

[0075] In Comparative Example 9, because a bevel with a semi-circular shape was not cut, although an assembly gap of 0.8 mm was also reserved compared to Example 3, the weld surface showed some bulges and some depressions, and the back of the weld showed discontinuous bottom hump and incomplete penetration. The reasons are similar to those in Comparative Example 1.

[0076] Comparative Example 10, compared to Example 3, did not cut a bevel with a semi-circular shape, nor did it leave an assembly gap. The weld front was well formed and the excess height was uniform, but the excess height was too high. However, the weld back was not fully penetrated, for reasons similar to Comparative Example 1.

[0077] Comparative Example 11, compared to Example 3, only changed the parameters of each part of the semi-circular bevel. The parameter values ​​of each part were all lower than the corresponding parameter values ​​in Example 3, and also lower than the optimal parameter range for the semi-circular bevel. The weld front was poorly formed, exhibiting an uneven surface, and a small number of bottom humps appeared on the back of the weld, with most areas showing incomplete penetration. The causes were similar to those in Comparative Example 3.

[0078] Comparative Example 12, compared to Example 1, only changed the parameters of each part of the serrated bevel. The parameter values ​​of each part were higher than the corresponding parameter values ​​of Example 3, and also higher than the optimal parameter range values ​​of the semi-circular bevel. The weld face showed collapse and poor formation, and the weld back showed discontinuous, large bottom humps. The cause of this was similar to that of Comparative Example 4.

[0079] As can be seen from Examples 1-3 and Comparative Examples 1-12, the semi-circular bevel cut by the integrated blanking and beveling process has the following parameter ranges: semi-circular radius R is 0.6mm to 0.9mm, semi-circular concavity depth H is 0.4mm to 0.6mm, and horizontal distance S between adjacent semi-circles is 0.1mm to 0.15mm. The bevel with the above parameter range obtains the precise size of the reserved assembly gap. Compared with narrow gaps, no gaps, or gaps that are too small or too large (outside the parameter range of the semi-circular bevel), this type of semi-circular bevel gap makes it easier to obtain a high-quality welded joint under the condition of single-sided welding and double-sided forming welding using laser-MAG composite welding.

[0080] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-functional composite processing method integrating laser cutting, beveling, and composite welding, characterized in that, Includes the following steps: S1. A laser cutting system is used to cut medium-thick plates, and during the cutting process, a continuous bevel with a semi-circular cross-section is simultaneously cut at the edge of the plate to be welded. S2. Clean the bevel of the board and its adjacent areas to remove the oxide layer and cutting residue; S3. Place the two plates to be welded with their beveled edges facing each other, and splice and clamp them together so that the bevels on the two plates are aligned and the mating surfaces are tightly fitted. S4. Use laser-MAG composite welding process to perform positioning spot welding on the clamped plates; S5. Using laser-MAG composite welding process, single-sided welding and double-sided forming welding are performed on the joints of plates after the positioning spot welding.

2. The multiple composite processing method according to claim 1, characterized in that, In step S1, the medium-thick plate specimen is a carbon steel plate with a thickness range of 10 to 16 mm.

3. The multiple composite processing method according to claim 2, characterized in that, In step S1, the geometric parameters of the continuous semi-circular bevels are: the radius R of the semi-circle is 0.6 to 0.9 mm, the depth H of the semi-circle concavity is 0.4 to 0.6 mm, and the horizontal distance S between the centers of adjacent semi-circles is 0.1 to 0.15 mm.

4. The multiple composite processing method according to claim 3, characterized in that, In step S1, the laser cutting process parameters are: cutting power of 30-60kW, cutting speed of 10-18m / min, focal position of -2--3mm, and cutting gas pressure of 6-7bar.

5. The multiple composite processing method according to claim 3 or 4, characterized in that, In step S3, the medium-thick plate is rigidly clamped using tooling fixtures, and the horizontal distance S between adjacent semicircles of the bevel corresponds to each other.

6. The multiple composite processing method according to claim 1, characterized in that, In step S4, the spot welding process parameters are as follows: laser power is 3-5kW, defocusing amount is -2--4mm, laser deflection angle is 5°, welding wire diameter is 1.2mm, welding speed is 1.0-1.5m / min, wire feed speed is 6-8m / min, welding current is 200-234A, wire spacing is 2-3mm, and gas flow rate is 15-20 L / min.

7. The multiple composite processing method according to claim 1, characterized in that, In step S5, the welding process parameters are as follows: laser power is 7-11kW, welding speed is 1.8-2.0m / min, defocusing amount is -2--4mm, welding wire diameter is 1.2mm, wire feed speed is 11.5-17.5m / min, welding current is 322-439A, wire spacing is 2-3mm, and gas flow rate is 15-20L / min.

Images