Laser welding joint structure and welding method
By setting special-shaped holes in the welded joints of ductile iron and steel to dissipate welding stress, the problems of welding cracks and high preheating temperatures are solved, and high-quality welding and cost reduction are achieved.
Patent Information
- Application Number
- CN202411511407.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2024-12-24
AI Technical Summary
Ductile cast iron and steel are prone to welding cracks during welding, resulting in high preheating temperature and high cost.
Using laser welded joint structure, by setting special-shaped holes parallel to the weld seam on the special-material structural parts of the welded joint, the bottom end of the special-shaped hole is an opening, so as to achieve welding stress dissipation, and reduce or avoid preheating during welding. Welding of conventional materials.
Reduce the concentration of welding stress, reduce crack generation, improve welding quality and strength, reduce preheating energy consumption, avoid the use of high vanadium and high nickel welding materials, and simplify the process flow.
Smart Images
Figure CN119175459A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of dissimilar joint welding, and in particular to a laser welding joint structure and a welding method. Background Art
[0002] The welding of ductile iron and steel currently involves arc welding, oxy-acetylene gas welding, CO2 gas shielded welding, vacuum diffusion welding and brazing. These methods have their own characteristics and are suitable for different welding needs and conditions.
[0003] For arc welding: When welding ductile iron and carbon steel, arc hot welding and cold welding can be used. For arc hot welding, the preheating temperature before welding is generally 500~700℃, and nickel-based alloy electrodes with good plasticity and high crack resistance are required to improve welding quality. Arc cold welding has high productivity, but attention should be paid to problems that may be caused by rapid cooling, such as chilling structure and welding deformation. In order to prevent chilling structure in heterogeneous welds, high-vanadium electrodes and nickel-iron electrodes, such as Z408 electrodes or Z438 electrodes, are usually selected to improve the crack resistance and machinability of the weld.
[0004] CO2 gas shielded welding: Applicable to the welding of ductile iron and low carbon steel (such as No. 20 steel, No. 15 steel). Using H08Mn2SiA welding wire and surfacing a high vanadium transition layer on the groove of ductile iron can effectively eliminate the white structure and improve the tensile strength of the welded joint. This method is favored by welders because of its fast melting speed, shallow melting depth, and convenient adjustment of welding parameters.
[0005] The welding process of ductile iron and steel is widely used in the automotive industry, such as the welding of drive shafts, differentials and bridge frames: As a typical product, the automotive drive shaft is usually welded by ductile iron QT400 and 20 steel pipe through arc cold welding. This process includes pre-welding cleaning, selection of suitable welding rods, control of welding current and voltage, and use of low current, low voltage, short arc welding and other technical points to ensure welding quality.
[0006] In summary, there are many different welding methods for ductile iron and steel, but they all require preheating, beveling, and adding expensive high-vanadium and high-nickel welding materials to ensure performance. This is mainly because when welding ductile iron and steel, a lot of stress will accumulate near the fusion zone on one side of the steel, and cracks are prone to occur in the weld joint area. In severe cases, the weld and the parent metal may "peel off". Therefore, when welding ductile iron and carbon steel, beveling and adding expensive high-vanadium and high-nickel welding materials are required, and sometimes high-temperature preheating is required. In recent years, high-strength steel has been widely used in the automotive industry, resulting in the preheating temperature of ductile iron and high-strength steel often cannot exceed 300°C due to the heat treatment heat of high-strength steel. Otherwise, the strength performance of high-strength steel will decrease significantly and cannot meet the mechanical performance requirements of parts. Summary of the invention
[0007] The object of the present invention is to provide a laser welding joint structure to solve the problems of high preheating temperature and high cost during welding of ductile iron and steel in the prior art.
[0008] In order to solve the above problems, the present invention proposes a laser welding joint structure, and the technical solution adopted is: A laser welding joint structure includes a first dissimilar material structural member and a second dissimilar material structural member, a welding joint is arranged between the first dissimilar material structural member and the second dissimilar material structural member, the welding joint includes a first welding surface of the welding end face of the first dissimilar material structural member and a second welding surface of the welding end face of the second dissimilar material structural member, a butt weld is formed between the first welding surface and the second welding surface, and at least one of the first dissimilar material structural member and the second dissimilar material structural member is provided with a special-shaped hole parallel to the butt weld and penetrating the corresponding dissimilar material structural member near the butt weld, the bottom end position of the special-shaped hole is an opening setting, and the distance from a position on the butt weld that is on the same horizontal line as the bottom end position of the special-shaped hole to the upper surface of the butt weld is the welding weld.
[0009] Furthermore, in a direction parallel to the butt weld, the distance between the bottom end position of the special-shaped hole and its corresponding upper end position is the weld root depth difference, and the weld root depth difference is 0.45~3.0mm; the distance between the bottom end position of the special-shaped hole and the upper surface of the welding weld is the weld thickness, and the weld thickness is 3.0~15mm.
[0010] Furthermore, the first and second heterogeneous material structural members are provided with a first and a second heterogeneous material hole near the butt weld, which are parallel to the butt weld and penetrate the first and second heterogeneous material structural members, and the bottom ends of the first and the second heterogeneous material structural members are on the same horizontal line; the first and the second heterogeneous material holes are symmetrically arranged relative to the butt weld.
[0011] Furthermore, the welding weld adopts a non-groove or a V-groove, the V-groove is symmetrically arranged relative to the butt weld, the surface width of the V-groove is greater than 0.6mm, and the root thickness of the V-groove is 1.5~3.0mm.
[0012] Furthermore, the first special-shaped hole and the second special-shaped hole are both arc-shaped openings, and the arc-shaped surfaces of the arc-shaped openings are arranged toward the upper surface of the butt weld. On the same horizontal line of the bottom ends of the two arc-shaped openings, the distance between adjacent arc-shaped surfaces on the two arc-shaped openings is 0.2~2.0mm, and the distance between opposite arc-shaped surfaces on the two arc-shaped openings is 2.0~10mm.
[0013] Furthermore, the materials of the first heterogeneous material structural member and the second heterogeneous material structural member are steel and cast iron respectively, or the same type of steel, or different types of steel, or the same type of cast iron, or different types of cast iron; wherein the carbon equivalent of the steel is ≤1.0; and the cast iron is ductile iron or grey cast iron.
[0014] Beneficial effect: The present invention is an improved invention. The present invention provides a special-shaped hole parallel to the butt weld and penetrating the corresponding special-shaped structural member near the butt weld on at least one of the first special-shaped structural member and the second special-shaped structural member. The bottom end of the special-shaped hole is opened. At the same time, the distance from the position on the butt weld that is on the same horizontal line as the bottom end of the special-shaped hole to the upper surface of the butt weld is determined as the welding weld, so that the stress generated by the dissimilar joints or the same joints during welding is dissipated.
[0015] The laser welding joint structure of the present invention has the following advantages: 1. When in use, dissimilar joints or homogeneous joints will accumulate great stress during welding and concentrate it at the weld root. By setting special-shaped holes in the weld joints, the welding stress can be reduced and dissipated, and the influence of stress concentration on the weld root can be reduced, thereby solving the problem of stress concentration at the weld root, reducing the generation of cracks, and improving the organization and performance of the weld joints; 2. Since the arrangement of the special-shaped hole realizes stress dissipation, the welded joint of the present invention does not need to be preheated or a lower preheating temperature is used during welding, and only one of the two heterogeneous material structural parts needs to be preheated, while the other does not need to be preheated, thereby realizing low-temperature preheating, which can reduce the consumption of preheating energy for the welded joint, increase the cooling speed of the welding area, and help to improve the strength of the welded joint and further improve the welding quality; 3. The laser welding joint structure of the present invention can ensure the performance without adding expensive high-vanadium and high-nickel welding materials; 4. The welding seam in the laser welding joint structure of the present invention does not need to be preheated and does not need to be post-heat treated after welding, and the process is simple; 5. The materials corresponding to the first heterogeneous material structural member and the second heterogeneous material structural member in the laser welding joint structure of the present invention can be conventional heterogeneous or homogeneous materials that are easy to weld, or heterogeneous or homogeneous materials that are not easy to weld, and have a wide range of applications.
[0016] The present invention also provides a welding method for a laser welded joint structure, which is used for welding the above-mentioned laser welded joint structure, and comprises the following steps: S1, processing a first welding surface of a welding end surface of a first structural component made of different materials and a second welding surface of a welding end surface of a second structural component made of different materials, so that a butt weld is formed between the first welding surface and the second welding surface; S2, a special-shaped hole parallel to the butt weld and penetrating the corresponding special-shaped structure is provided on at least one of the first special-shaped structure and the second special-shaped structure near the butt weld, and the bottom end of the special-shaped hole is opened; S3, processing the welding seam between the position on the same horizontal line as the bottom end of the special-shaped hole and the upper surface of the butt weld into a non-groove or V-groove; S4, laser welding is used to fill welds without grooves or V-grooves.
[0017] Furthermore, before S4, the welding method of the laser welded joint structure also includes preheating the weld or preheating one of the two dissimilar structural parts before welding; the preheating temperature is 150-300°C.
[0018] Furthermore, in S4, the laser welding speed is ≥1m / min, and the laser welding power is the thickness of the weld. (0.6~1.2)KW.
[0019] Further, in S4, during the welding process, compressed air is used for side blowing just above the welding seam.
[0020] Beneficial effects: The present invention provides a special-shaped hole parallel to the butt weld and penetrating the corresponding dissimilar material structural member near the butt weld on at least one of the first dissimilar material structural member and the second dissimilar material structural member, and the bottom end of the special-shaped hole is opened, which can reduce and dissipate welding stress and reduce the influence of stress concentration on the weld root, thereby solving the problem of stress concentration at the weld root; at the same time, the welding method of the laser welding joint structure of the present invention does not need to preheat the welding weld and the dissimilar material structural member, and can also preheat the welding weld and the dissimilar material structural member, and has a wide range of applications; in addition, the weld joint without weld groove of the present invention does not need to add expensive high-vanadium and high-nickel welding materials to ensure the performance, the welding weld does not need to be protected by inert gas during the welding process, and does not need to be post-heated after welding, and the process is simple.
[0021] In the direction parallel to the butt weld, the distance between the bottom end position of the special-shaped hole and its corresponding upper end position is the weld root depth difference, and the weld root depth difference is 0.45~3.0mm; the distance between the bottom end position of the special-shaped hole and the upper surface of the welding weld is the weld thickness, and the weld thickness is 3.0~15mm, which effectively realizes stress dissipation and ensures the formation and effectiveness of welding.
[0022] The first and second heterogeneous material structural members are provided with a first special-shaped hole and a second special-shaped hole near the butt weld, which are parallel to the butt weld and penetrate the first and second heterogeneous material structural members, and the bottom ends of the first special-shaped hole and the second special-shaped hole are on the same horizontal line; the first special-shaped hole and the second special-shaped hole are symmetrically arranged relative to the butt weld, so that the first special-shaped hole and the second special-shaped hole dissipate stress evenly and quickly.
[0023] The welding weld adopts a non-groove or a V-shaped groove. The welding weld adopts a non-groove setting to complete the welding of the weld, which has a simple structure and is easy to operate; the welding weld adopts a V-shaped groove setting, and the V-shaped groove is symmetrically arranged relative to the butt weld. The surface width of the V-shaped groove is greater than 0.6mm, and the root thickness of the V-shaped groove is 1.5~3.0mm, which can ensure that the root of the welding weld can be welded through and obtain better weld formation.
[0024] The first special-shaped hole and the second special-shaped hole are both arc-shaped openings, and the arc-shaped surfaces of the arc-shaped openings are arranged toward the upper surface of the butt weld. The structure is simple and can effectively achieve stress dissipation. On the same horizontal line of the bottom ends of the two arc-shaped openings, the distance between adjacent arc-shaped surfaces on the two arc-shaped openings is 0.2~2.0mm, and the distance between opposite arc-shaped surfaces on the two arc-shaped openings is 2.0~10mm, which further ensures that the two arc-shaped openings can effectively and quickly dissipate stress and prevent failure of stress dissipation during welding melting.
[0025] Before S4, the welding method of the laser welding joint structure also includes preheating the weld or preheating one of the two heterogeneous structural parts before welding; the temperature of the preheating treatment is 150~300℃, ensuring a low preheating temperature while ensuring that the temperature heat is transferred to the non-preheated heterogeneous structural part. Before welding, one of the two heterogeneous structural parts is preheated, and the other does not need to be preheated. Only the heat conduction of the preheated structural part is needed to control the temperature of the non-preheated structural part, thereby achieving low-temperature preheating, which can reduce the consumption of preheating energy for the weld joint, increase the cooling rate of the welding area, and help to improve the strength of the weld joint and further improve the welding quality. In S4, the laser welding speed is ≥1m / min, and the laser power is the thickness of the weld. (0.6~1.2)KW, ensuring that the welding seam is completed quickly and effectively, and ensuring the quality of the welding.
[0026] In S4, during the welding process, compressed air is used for side blowing just above the welding seam to ensure that the plasma generated during welding is blown away in time, thereby reducing the influence of the plasma on the laser absorption efficiency of the weld. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 1 is a schematic structural diagram of a joint structure without a groove in Example 2 of a laser welding joint structure of the present invention; Figure 2 1 is a schematic structural diagram of a V-groove joint structure in Example 2 of a laser welding joint structure of the present invention; Figure 3 is a schematic diagram of the welding seam after welding in Example 1 of the welding method of the laser welding joint structure of the present invention; In the figure, 1. ductile iron structural part, 2. high-strength steel structural part, 3. arc opening, 4. welding weld, 5. V-shaped groove, 6. root thickness of V-shaped groove. DETAILED DESCRIPTION
[0028] As cited in the background art, in the prior art, welding cracks are easily generated when ductile iron and steel are welded, which results in high preheating temperature and high cost during welding. Therefore, the present invention provides a laser welding joint structure, comprising a first dissimilar material structural member and a second dissimilar material structural member, a welding joint is arranged between the first dissimilar material structural member and the second dissimilar material structural member, for realizing welding of the first dissimilar material structural member and the second dissimilar material structural member; the welding joint comprises a first welding surface of the welding end face of the first dissimilar material structural member and a second welding surface of the welding end face of the second dissimilar material structural member, a butt weld is formed between the first welding surface and the second welding surface, for welding the first dissimilar material structural member and the second dissimilar material structural member together; a special-shaped hole parallel to the butt weld and penetrating the corresponding dissimilar material structural member is arranged near the butt weld on at least one of the first dissimilar material structural member and the second dissimilar material structural member, the bottom end position of the special-shaped hole is opened, for reducing and dissipating welding stress; the distance from the position on the butt weld that is on the same horizontal line as the bottom end position of the special-shaped hole to the upper surface of the butt weld is the welding weld, so as to ensure that the special-shaped hole is at the root of the welding weld and reduce stress The influence of force concentration on the weld root and the solution of the stress concentration problem of the weld root can reduce and dissipate the welding stress and reduce the influence of stress concentration on the weld root, thereby solving the stress concentration problem of the weld root, thereby reducing the generation of cracks and improving the structure and performance of the weld joint; since the setting of the special-shaped hole realizes stress dissipation, the welding joint of the present invention does not need to preheat the welding weld or one of the two heterogeneous material structural parts during welding, or can use a lower preheating temperature and only need to preheat one of the two heterogeneous material structural parts, while the other does not need to be preheated, thereby realizing low-temperature preheating, which can reduce the consumption of preheating energy for the welding joint, increase the cooling rate of the welding area, and is beneficial to improve the strength of the welding joint and further improve the welding quality; the laser welding of cast iron and steel dissimilar joints of the present invention does not need to add expensive high-vanadium and high-nickel welding materials to ensure the performance, and the welding weld does not need to be post-heat treated after welding, and the process is simple.
[0029] Specific embodiment 1 of the laser welding joint structure of the present invention: In this embodiment, Figure 1As shown, the laser welding joint structure includes a first heterogeneous material structural member and a second heterogeneous material structural member, a welding joint is arranged between the first heterogeneous material structural member and the second heterogeneous material structural member, the welding joint includes a first welding surface of the welding end face of the first heterogeneous material structural member and a second welding surface of the welding end face of the second heterogeneous material structural member, a butt weld is formed between the first welding surface and the second welding surface, and the first heterogeneous material structural member and the second heterogeneous material structural member are respectively provided with a first special-shaped hole and a second special-shaped hole parallel to the butt weld and penetrating the first heterogeneous material structural member and the second heterogeneous material structural member near the butt weld, the bottom ends of the first special-shaped hole and the second special-shaped hole are on the same horizontal line, and the bottom ends of the first special-shaped hole and the second special-shaped hole are both open. The first special-shaped hole and the second special-shaped hole are symmetrically arranged relative to the butt weld, and the distance from the position on the butt weld that is on the same horizontal line as the bottom ends of the first special-shaped hole and the second special-shaped hole to the upper surface of the butt weld is welding weld 4. Among them, in the direction parallel to the butt weld, the distance between the bottom end position of the first special-shaped hole and the second special-shaped hole and their corresponding upper end position is the weld root depth difference, and the weld root depth difference is 0.45~3.0mm; the distance between the bottom end position of the first special-shaped hole and the second special-shaped hole and the upper surface of the welding weld 4 is the weld thickness, and the weld thickness is 3.0~15mm, which effectively realizes stress dissipation and ensures the forming and effectiveness of welding. The materials of the first heterogeneous material structural part and the second heterogeneous material structural part are steel and cast iron, respectively, and the carbon equivalent of steel is ≤1.0; the cast iron is ductile iron or gray cast iron, and the carbon equivalent of steel is calculated according to formula 1: Formula 1 Specifically, Figure 1 As shown, the first heterogeneous material structural member is a ductile iron structural member 1, the second heterogeneous material structural member is a high-strength steel structural member 2, the first heterogeneous hole and the second heterogeneous hole are both arc-shaped openings 3, the arc surface of the arc-shaped opening 3 is arranged toward the upper surface of the butt weld, and on the same horizontal line at the bottom end position of the two arc-shaped openings 3, the distance between the adjacent arc-shaped surfaces on the two arc-shaped openings 3 is 0.2~2.0mm, and the distance between the opposite arc-shaped surfaces on the two arc-shaped openings 3 is 2.0~10mm. The structure is simple, and during welding, it further ensures that the two arc-shaped openings can effectively and quickly dissipate stress, while preventing the failure of dissipating stress during the welding melting process.
[0030] In other embodiments, in the laser welding joint structure, a special-shaped hole parallel to the butt weld and penetrating the first special-shaped structural member is provided near the butt weld on the first special-shaped structural member, and the bottom end of the special-shaped hole is open; no special-shaped hole is provided on the second special-shaped structural member.
[0031] In other embodiments, in the laser welding joint structure, a special-shaped hole parallel to the butt weld and penetrating the second special-shaped structural member is provided near the butt weld on the second special-shaped structural member, and the bottom end of the special-shaped hole is open; no special-shaped hole is provided on the first special-shaped structural member.
[0032] In other embodiments, the first special-shaped hole and the second special-shaped hole may be asymmetrically arranged relative to the butt weld, that is, the distance from the butt weld to the first special-shaped hole is different from the distance from the butt weld to the second special-shaped hole; or the shapes of the first special-shaped hole and the second special-shaped hole may be different.
[0033] In other embodiments, the first special-shaped hole and the second special-shaped hole may be elliptical holes or T-shaped holes, as long as the stress can be dissipated.
[0034] In other embodiments, the first heterogeneous material structural part may be a ductile iron structural part, and the second heterogeneous material structural part may be a low alloy steel structural part; the first heterogeneous material structural part may be a ductile iron structural part, and the second heterogeneous material structural part may be a stainless steel structural part; the first heterogeneous material structural part may be a gray cast iron structural part, and the second heterogeneous material structural part may be a high-strength steel structural part; the first heterogeneous material structural part may be a gray cast iron structural part, and the second heterogeneous material structural part may be a low alloy steel structural part; the first heterogeneous material structural part may be a gray cast iron structural part, and the second heterogeneous material structural part may be a stainless steel structural part; the first heterogeneous material structural part may be a low alloy steel structural part, and the second heterogeneous material structural part may be a low alloy steel structural part that is the same as or different from the first heterogeneous material structural part; wherein the carbon equivalent of steel is ≤1.0; specifically, the first heterogeneous material structural part may be a ductile iron 600 structural part, and the second heterogeneous material structural part may be a 40Cr structural part.
[0035] In other embodiments, the first heterogeneous material structural part and the second heterogeneous material structural part can be the same type of steel and steel structural part; the first heterogeneous material structural part and the second heterogeneous material structural part can also be different types of steel and steel structural parts; the first heterogeneous material structural part and the second heterogeneous material structural part can also be the same type of cast iron and cast iron structural part; the first heterogeneous material structural part and the second heterogeneous material structural part can also be different types of cast iron and cast iron structural parts; specifically, the first heterogeneous material structural part can be a 40Cr structural part, and the second heterogeneous material structural part can be a 40Cr structural part; the first heterogeneous material structural part can be a ductile iron 600 structural part, and the second heterogeneous material structural part can be a ductile iron 600 structural part.
[0036] Specific embodiment 2 of the laser welding joint structure of the present invention: Based on the above technical concept of the present invention, or based on the above specific embodiment of the present invention, another embodiment is provided below.
[0037] In this embodiment, Figure 1As shown, the welding weld 4 adopts a non-groove setting, the weld root depth difference of the arc-shaped opening 3 is 0.45~3.0mm, and on the same horizontal line of the bottom end position of the two arc-shaped openings 3, the distance between the arc-shaped surfaces on the two arc-shaped openings 3 is 0.2~2.0mm, and the distance between the opposite arc-shaped surfaces on the two arc-shaped openings 3 is 2.0~10mm.
[0038] In another embodiment, if Figure 2 As shown, the welding seam 4 adopts a V-shaped groove 5, which is symmetrically arranged relative to the butt weld, and two arc-shaped openings 3 are opened at the root of the V-shaped groove 5, wherein the surface width of the V-shaped groove 5 is greater than 0.6mm, specifically 0.8-20mm, and the root thickness 6 of the V-shaped groove is 1.5-3.0mm, which can ensure that the root can be welded through and obtain a better weld formation. Figure 2 As shown, the root thickness 6 of the V-groove refers to the distance from the bottom of the V-groove to the position on the butt weld that is on the same horizontal line as the bottom positions of the two arc-shaped openings 3. When welding the V-groove, the corresponding weld needs to be filled with welding wire, and the chemical composition of the welding wire is selected according to the chemical composition of the parent material. For example, when welding 42CrMo steel / 42CrMo steel, the welding wire uses an iron-based welding wire with an iron content of >50% and a nickel content of >40%.
[0039] Specific embodiment 1 of the welding method of the laser welding joint structure of the present invention: In this embodiment, Figure 3 As shown, for the welding of the above-mentioned laser welding joint structure, the welding method of the laser welding joint structure includes the following steps: First, a first welding surface of a welding end surface of a first structural component made of different materials and a second welding surface of a welding end surface of a second structural component made of different materials are processed so that a butt weld is formed between the first welding surface and the second welding surface; Secondly, a first special-shaped hole and a second special-shaped hole are respectively processed on the first special-shaped structural member and the second special-shaped structural member near the butt weld, parallel to the butt weld and penetrating the first special-shaped structural member and the second special-shaped structural member, the bottom ends of the first special-shaped hole and the second special-shaped hole are on the same horizontal line, and the bottom ends of the first special-shaped hole and the second special-shaped hole are both open; Next, the welding weld 4 between the position on the butt weld that is on the same horizontal line as the bottom ends of the first special-shaped hole and the second special-shaped hole and the upper surface of the butt weld is processed into a non-groove or V-shaped groove; Then, the welding seam is preheated before welding or one of the two heterogeneous structural parts is preheated, and the preheating temperature is 150-300°C; specifically, when the two heterogeneous structural parts are of different materials, the one with higher thermal conductivity is preheated before welding; when the two heterogeneous structural parts are of the same material, any one of the two heterogeneous structural parts is preheated before welding; Finally, laser welding is used to fill the weld seam 4 without groove or V-shaped groove, wherein the welding speed of laser welding is ≥1m / min, and the power of laser welding is the thickness of the weld seam 4. (0.6~1.2)KW, during the welding process, compressed air is used for side blowing just above the welding weld 4.
[0040] In other embodiments, the weld is not preheated before welding in step 4 or one of the two dissimilar structural members is not preheated.
[0041] In other embodiments, the weld may be shielded by an inert gas during the welding process.
[0042] Specifically, the first heterogeneous material structural member is a ductile iron structural member 1, and the second heterogeneous material structural member is a high-strength steel structural member 2. The welding of cast iron and steel includes the following steps: First, the first welding surface and the second welding surface of the ductile iron structural member 1 and the high-strength steel structural member 2 are processed so that a butt weld is formed between the first welding surface and the second welding surface; Secondly, two arc openings 3 are respectively processed on the ductile iron structural member 1 and the high-strength steel structural member 2 near the butt weld, which are parallel to the butt weld and penetrate the ductile iron structural member 1 and the high-strength steel structural member 2, and the bottom ends of the two arc openings 3 are on the same horizontal line and are symmetrically arranged relative to the butt weld. Specifically, the weld root depth difference of the arc opening 3 is 2.0 mm, and on the same horizontal line of the bottom ends of the two arc openings, the distance between adjacent arc surfaces on the two arc openings 3 is 2 mm, the distance between the opposite arc surfaces on the two arc openings 3 is 10 mm, and the weld thickness is 8 mm; Next, the welding seam 4 between the position on the butt weld that is on the same horizontal line as the bottom ends of the two arc-shaped openings 3 and the upper surface of the butt weld is processed into a V-shaped groove 5, wherein the V-shaped groove 5 is symmetrically arranged relative to the butt weld, the surface width of the V-shaped groove 5 is 1 mm, and the root thickness 6 of the V-shaped groove is 1.5 mm; Then, the ductile iron structural member 1 is preheated before welding, and the preheating temperature is 300°C. At this time, one side of the high-strength steel structural member 2 does not need to be preheated, and the temperature of the high-strength steel structural member 2 is controlled by heat conduction on the side of the ductile iron structural member 1. When the preheating temperature on the side of the ductile iron structural member 1 reaches the requirement, the temperature on the high-strength alloy steel side is controlled below the low-temperature tempering temperature; Finally, laser welding is used to fill the V-shaped groove 5. The welding speed of laser welding is 1m / min, and the power of laser welding is 5KW. At the same time, during the welding process, compressed air is used for side blowing just above the welding weld 4 to complete the welding of the weld.
[0043] In another embodiment, the first heterogeneous material structural member is a ductile iron structural member 1, and the second heterogeneous material structural member is a high-strength steel structural member 2, and the welding of cast iron and steel includes the following steps: First, the first welding surface and the second welding surface of the ductile iron structural member 1 and the high-strength steel structural member 2 are processed so that a butt weld is formed between the first welding surface and the second welding surface; Secondly, two arc openings 3 are respectively processed on the ductile iron structural member 1 and the high-strength steel structural member 2 near the butt weld, which are parallel to the butt weld and penetrate the ductile iron structural member 1 and the high-strength steel structural member 2, and the bottom ends of the two arc openings 3 are on the same horizontal line and are symmetrically arranged relative to the butt weld. Specifically, the weld root depth difference of the arc opening 3 is 1.0 mm, and on the same horizontal line of the bottom ends of the two arc openings, the distance between adjacent arc surfaces on the two arc openings 3 is 0.2 mm, the distance between the opposite arc surfaces on the two arc openings 3 is 4.2 mm, and the weld thickness is 6 mm; Next, the welding seam 4 between the position on the butt weld seam that is on the same horizontal line as the bottom ends of the two arc-shaped openings 3 and the upper surface of the butt weld seam is processed into a welding seam 4 without a groove; Then, the ductile iron structural member 1 is preheated before welding, and the preheating temperature is 150°C. At this time, one side of the high-strength steel structural member 2 does not need to be preheated, and the temperature of the high-strength steel structural member 2 is controlled by heat conduction on the side of the ductile iron structural member 1. When the preheating temperature on the side of the ductile iron structural member 1 reaches the requirement, the temperature on the high-strength alloy steel side is controlled below the low-temperature tempering temperature; Finally, laser welding is used to fill the weld seam 4 without a groove. The welding speed of the laser welding is 3m / min, and the power of the laser welding is 4.5KW. At the same time, during the welding process, compressed air is used for side blowing just above the weld seam 4 to complete the welding of the weld seam.
[0044] In another embodiment, the first heterogeneous material structural member is a 40Cr structural member, the second heterogeneous material structural member is a 40Cr structural member, and the welding of steel and steel comprises the following steps: First, a first welding surface and a second welding surface of a 40Cr structural member and a welding end of the 40Cr structural member are processed so that a butt weld is formed between the first welding surface and the second welding surface; Secondly, two arc openings 3 parallel to the butt weld and penetrating the 40Cr structural member and the 40Cr structural member are respectively processed near the butt weld on the 40Cr structural member and the 40Cr structural member, and the bottom ends of the two arc openings 3 are on the same horizontal line and are arranged opposite to the butt weld. Specifically, the weld heel depth of the arc opening 3 is 0.4 mm, and on the same horizontal line of the bottom ends of the two arc openings, the distance between adjacent arc surfaces on the two arc openings 3 is 0.4 mm, the distance between the opposite arc surfaces on the two arc openings 3 is 2 mm, and the weld thickness is 8 mm; Next, the welding seam 4 between the position on the butt weld seam that is on the same horizontal line as the bottom ends of the two arc-shaped openings 3 and the upper surface of the butt weld seam is processed into a V-shaped groove 5, the V-shaped groove 5 is symmetrically arranged relative to the butt weld seam, the surface width of the V-shaped groove 5 is 1.0 mm, and the root thickness 6 of the V-shaped groove is 6 mm; Finally, laser welding is used to fill the V-shaped groove 5. The weld can be protected by inert gas during the welding process. The laser welding speed is 1.2m / min, and the laser welding power is 6.4KW. At the same time, during the welding process, compressed air is used for side blowing just above the weld 4 to complete the welding of the weld.
[0045] Through the above description of the specific embodiments of the laser welding joint structure of the present invention, it can be seen that the laser welding joint structure of the present invention includes a first heterogeneous material structural member and a second heterogeneous material structural member, and a welding joint is arranged between the first heterogeneous material structural member and the second heterogeneous material structural member, for realizing the welding of the first heterogeneous material structural member and the second heterogeneous material structural member; the welding joint includes a first welding surface of the welding end face of the first heterogeneous material structural member and a second welding surface of the welding end face of the second heterogeneous material structural member, and a butt weld is formed between the first welding surface and the second welding surface, for welding the first heterogeneous material structural member and the second heterogeneous material structural member together; a special-shaped hole parallel to the butt weld and penetrating the corresponding special-shaped structural member is arranged on at least one of the first heterogeneous material structural member and the second heterogeneous material structural member near the butt weld, and the bottom end position of the special-shaped hole is an opening arrangement for reducing and dissipating welding stress; the distance from the position on the butt weld that is on the same horizontal line as the bottom end position of the special-shaped hole to the upper surface of the butt weld is the welding weld, so as to ensure that the special-shaped hole The root of the welding weld can reduce the influence of stress concentration on the weld root, solve the problem of stress concentration at the weld root, reduce and dissipate welding stress, reduce the influence of stress concentration on the weld root, thereby solve the problem of stress concentration at the weld root, thereby reducing the generation of cracks and improving the structure and performance of the welding joint; since the setting of the special-shaped hole can achieve stress dissipation, the welding joint of the present invention does not need to be preheated for the welding weld or one of the two heterogeneous material structural parts during welding, or a lower preheating temperature can be used and only one of the two heterogeneous material structural parts needs to be preheated, while the other does not need to be preheated, thereby achieving low-temperature preheating, which can reduce the consumption of preheating energy for the welding joint, increase the cooling rate of the welding area, and is beneficial to improving the strength of the welding joint and further improving the welding quality; the laser welding of cast iron and steel dissimilar joints of the present invention does not need to add expensive high-vanadium and high-nickel welding materials to ensure the performance, and the welding weld does not need to be post-heat treated after welding, and the process is simple.
[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.
Claims
1. A laser welding joint structure, characterized in that: It includes a first heterogeneous material structural member and a second heterogeneous material structural member, a welding joint is arranged between the first heterogeneous material structural member and the second heterogeneous material structural member, the welding joint includes a first welding surface of the welding end face of the first heterogeneous material structural member and a second welding surface of the welding end face of the second heterogeneous material structural member, a butt weld is formed between the first welding surface and the second welding surface, and at least one of the first heterogeneous material structural member and the second heterogeneous material structural member is provided with a special-shaped hole parallel to the butt weld and penetrating the corresponding special-shaped structural member near the butt weld, the bottom end position of the special-shaped hole is an opening setting, and the distance from a position on the butt weld that is on the same horizontal line as the bottom end position of the special-shaped hole to the upper surface of the butt weld is the welding weld.
2. The laser welding joint structure according to claim 1, characterized in that: In the direction parallel to the butt weld, the distance between the bottom end position of the special-shaped hole and its corresponding upper end position is the weld root depth difference, and the weld root depth difference is 0.45~3.0mm; the distance between the bottom end position of the special-shaped hole and the upper surface of the welding weld is the weld thickness, and the weld thickness is 3.0~15mm.
3. The laser welding joint structure according to claim 2, characterized in that: The first and second heterogeneous material structural members are provided with a first special-shaped hole and a second special-shaped hole near the butt weld, which are parallel to the butt weld and penetrate the first and second heterogeneous material structural members, and the bottom ends of the first special-shaped hole and the second special-shaped hole are on the same horizontal line; the first special-shaped hole and the second special-shaped hole are symmetrically arranged relative to the butt weld.
4. The laser welding joint structure according to claim 3, characterized in that: The welding weld adopts a non-groove or a V-groove, the V-groove is symmetrically arranged relative to the butt weld, the surface width of the V-groove is greater than 0.6mm, and the root thickness of the V-groove is 1.5-3.0mm.
5. The laser welding joint structure according to claim 4, characterized in that: The first special-shaped hole and the second special-shaped hole are both arc-shaped openings, and the arc-shaped surfaces of the arc-shaped openings are arranged toward the upper surface of the butt weld. On the same horizontal line of the bottom ends of the two arc-shaped openings, the distance between adjacent arc-shaped surfaces on the two arc-shaped openings is 0.2~2.0mm, and the distance between opposite arc-shaped surfaces on the two arc-shaped openings is 2.0~10mm.
6. The laser welding joint structure according to any one of claims 1 to 5, characterized in that: The materials of the first heterogeneous material structural member and the second heterogeneous material structural member are steel and cast iron respectively, or the same type of steel, or different types of steel, or the same type of cast iron, or different types of cast iron; wherein the carbon equivalent of the steel is ≤1.0; and the cast iron is ductile iron or grey cast iron.
7. A welding method for a laser welded joint structure according to any one of claims 1 to 6, characterized in that: The steps include: S1, processing a first welding surface of a welding end surface of a first structural component made of different materials and a second welding surface of a welding end surface of a second structural component made of different materials, so that a butt weld is formed between the first welding surface and the second welding surface; S2, a special-shaped hole parallel to the butt weld and penetrating the corresponding special-shaped structure is provided on at least one of the first special-shaped structure and the second special-shaped structure near the butt weld, and the bottom end of the special-shaped hole is opened; S3, processing the welding seam between the position on the same horizontal line as the bottom end of the special-shaped hole and the upper surface of the butt weld into a non-groove or V-groove; S4, laser welding is used to fill welds without grooves or V-grooves.
8. The welding method of the laser welding joint structure according to claim 7, characterized in that: Before S4, the welding method of the laser welded joint structure further includes preheating the weld or preheating one of the two heterogeneous material structural parts before welding; the preheating temperature is 150-300°C.
9. The welding method of the laser welding joint structure according to claim 7, characterized in that: In S4, the laser welding speed is ≥1m / min, and the laser welding power is the thickness of the weld. (0.6~1.2)KW.
10. The welding method of the laser welding joint structure according to claim 7, characterized in that: In S4, during the welding process, compressed air is used to perform side blowing directly above the welding seam.