CN118808987B

CN118808987B - Welding wire laser splice welding structural member, preparation method thereof and vehicle

Info

Publication number: CN118808987B
Application number: CN202411296024.6A
Authority: CN
Inventors: 张兴孟
Original assignee: Xiaomi Automobile Technology Co Ltd
Current assignee: Xiaomi Automobile Technology Co Ltd
Priority date: 2024-09-14
Filing date: 2024-09-14
Publication date: 2024-12-17
Anticipated expiration: 2044-09-14
Also published as: CN118808987A

Abstract

The present disclosure relates to a welding wire, a laser splice welding structure, a method of manufacturing the same, and a vehicle, wherein the welding wire contains 0.26 to 0.48 wt% of C,0.1 to 0.3 wt% of Si,0.8 to 3 wt% of Mn,0.1 to 0.4 wt% of Cr,0.03 to 0.1 wt% of Zr, and the balance of Fe and unavoidable impurity elements, based on the total weight of the welding wire. The welding wire provided by the disclosure can realize high-quality laser splice welding of high-strength-level steel, has high weld strength, good toughness, strong hydrogen-induced delayed cracking resistance, strong universality and low cost, and is suitable for producing other key industrial components such as high-strength, high-safety and lightweight vehicle structural parts.

Description

Welding wire laser splice welding structural member, preparation method thereof and vehicle

Technical Field

The present disclosure relates to a welding wire, a laser splice welded structure, a method of making the same, and a vehicle.

Background

In recent years, with urgent demands for energy saving and environmental protection and increased safety requirements, weight saving and safety have become popular pursuits for automobile manufacturing, and high strength steel has received increasing attention in the field. In automobile manufacturing, the laser tailor-welding method can weld steel plates with different thicknesses, different materials and even different surface states together. This approach allows the desired materials to be placed in the desired locations of the part, thereby achieving optimal cost, weight and safety performance. The sheet after laser splice welding is subjected to hot stamping, so that the number of vehicle body parts can be reduced while the weight is reduced, the manufacturing precision is improved, the parts have better collision performance, and the light weight effect is more obvious.

In order to meet more severe collision requirements and achieve the greatest degree of weight reduction, various tailor welded components have been developed. The splice welding component can be formed by splice welding materials (such as steel plates) with the same strength and thickness, and can also be formed by splice welding materials with different strengths (the strength level comprises, for example, 500MPa, 1000MPa, 1500MPa, 2000MPa and the like) and thicknesses. However, in the prior art, when a high-strength grade material is subjected to laser welding to form a welding part, a welding wire with high carbon and high manganese is often adopted to obtain a high-strength welding line, but the obtained welding line is often insufficient in toughness, and the risk of delayed cracking caused by hydrogen is high.

Disclosure of Invention

The invention aims to provide a welding wire, a laser splice welding structural member, a preparation method thereof and a vehicle, so as to improve the strength and toughness of a welding seam and improve the hydrogen induced delayed cracking resistance of the welding seam.

To achieve the above object, according to a first aspect of the present disclosure, there is provided a welding wire, which contains 0.26 to 0.48 wt% of C,0.1 to 0.3 wt% of Si,0.8 to 3 wt% of Mn,0.1 to 0.4 wt% of Cr,0.03 to 0.1 wt% of Zr, and the balance of Fe and unavoidable impurity elements, based on the total weight of the welding wire.

Optionally, the welding wire further comprises Ti, nb and Co, wherein the welding wire comprises 0.01-0.08 wt% of Ti, 0.01-0.06 wt% of Nb and 0.01-0.1 wt% of Co based on the total weight of the welding wire.

Optionally, the total content of the Ti element and the Nb element is 0.02-0.1 wt% based on the total weight of the welding wire.

Optionally, in the welding wire, the weight ratio of Zr element to Ti element is not less than 2.5.

Optionally, the welding wire contains 0.3-0.45 wt% of C, 0.15-0.25 wt% of Si, 1-2.8 wt% of Mn, 0.1-0.4 wt% of Cr, 0.03-0.1 wt% of Zr, 0.01-0.08 wt% of Ti, 0.01-0.06 wt% of Nb, 0.01-0.1 wt% of Co, and the balance of Fe and unavoidable impurity elements based on the total weight of the welding wire.

According to a second aspect of the disclosure, a method for manufacturing a laser splice welding structural member is provided, and the method comprises the steps of performing laser splice welding on two plated steel plates through a laser filler wire welding process by adopting the welding wire disclosed in the first aspect of the disclosure, so as to obtain a splice welding steel plate.

Optionally, the coated steel sheet is an al—si coated steel sheet, and the tensile strength of the al—si coated steel sheet is not less than 2000MPa.

Optionally, the Al-Si plated steel sheet includes a substrate and a plating layer disposed on a surface of the substrate;

Optionally, the substrate contains 0.27 to 0.39 wt% of C,0.1 to 0.6 wt% of Si,0.7 to 2.2 wt% of Mn,0.1 to 0.4 wt% of Al, not more than 0.1wt% of P, not more than 0.1wt% of S, not more than 0.7 wt% of Cr, not more than 0.01 wt% of B, not more than 0.16 wt% of Ti, not more than 0.1wt% of Nb, not more than 0.3 wt% of V, the balance being Fe and unavoidable impurity elements based on the total weight of the substrate, and/or,

Based on the total weight of the coating, the coating contains 80-95 wt% of Al, 5-11 wt% of Si, and the balance of Fe and unavoidable impurity elements.

Optionally, the thickness of the plating layer is 6-19 μm, and/or the thickness of the substrate is 1-2.5 mm.

Optionally, the laser welding conditions comprise a butt joint gap of 0-0.5 mm, a welding speed of 80-120 mm/s, a welding wire diameter of 0.8-1.2 mm and a wire feeding speed of 80-110 mm/s.

Optionally, the method further comprises the steps of carrying out hot stamping forming on the welding steel plate to obtain a laser welding structural member;

Optionally, the hot stamping forming conditions comprise a heating temperature of 880-930 ℃, a heating time of 200-480 s, a quenching cooling speed of 30-50 ℃ per second and a quenching cooling time of 15-40 s.

In a third aspect of the present disclosure, there is provided a laser tailor welded construction made by the method of the second aspect of the present disclosure;

Optionally, the yield strength of the laser splice welding structural member is not lower than 1200MPa, the tensile strength is not lower than 1700MPa, the elongation after fracture is not lower than 4.5%, and the weld hardness is not lower than 520Hv.

In a fourth aspect of the present disclosure, there is provided a vehicle comprising the laser tailor welded construction of the third aspect of the present disclosure.

Through above-mentioned technical scheme, the welding wire that this disclosure provided can realize the high quality laser welding to high strength level steel, and welding seam intensity is high, toughness is good, and hydrogen-induced delayed cracking resistance is strong, has stronger commonality and with low costs, is suitable for other key industrial components such as production high strength, high security and lightweight vehicle structure spare.

Additional features and advantages of the present disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification, illustrate the disclosure and together with the description serve to explain, but do not limit the disclosure. In the drawings:

FIG. 1 shows a golden phase diagram of a laser tailor welded construction of embodiment 9 of the present disclosure;

FIG. 2 shows a photograph of a tensile fracture test of a laser tailor welded structure of example 9 of the present disclosure;

fig. 3 shows a hardness profile of a laser tailor welded structure of example 9 of the present disclosure.

Detailed Description

Specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the disclosure, are not intended to limit the disclosure.

A first aspect of the present disclosure provides a welding wire, which contains 0.26 to 0.48 wt% of C (carbon), 0.1 to 0.3 wt% of Si (silicon), 0.8 to 3 wt% of Mn (manganese), 0.1 to 0.4 wt% of Cr (chromium), 0.03 to 0.1 wt% of Zr (zirconium), and the balance of Fe (iron) and unavoidable impurity elements, based on the total weight of the welding wire.

According to the welding wire disclosed by the invention, a proper amount of C element is added to improve the strength and hardness of the material, mn element is beneficial to expanding an austenite phase region (gamma-phase region) in the material and forming an infinite solid solution, the hardenability of the material is improved, a proper amount of Cr element is beneficial to reducing the critical transition temperature of the material, improving the hardenability and promoting the wide formation of a martensitic structure in the quenching process, and a proper amount of Zr element and C element are added to form stable carbide, so that coarsening of austenite grains is effectively inhibited, the martensitic structure is promoted to be finer, and the toughness of the material is improved.

In one embodiment, the welding wire further comprises Ti (titanium), nb (niobium) and Co (cobalt). Through the composite addition of Nb element and Ti element, the fine precipitates formed by Nb and Ti, namely carbonitride, can inhibit the recrystallization and growth of austenite grains through pinning action, the fine dispersed second-phase precipitates also provide remarkable precipitation strengthening action, the strength and hardness of the material are effectively improved, and the addition of a proper amount of Co element is beneficial to improving the martensitic transformation starting temperature (Ms point) so as to obtain self-tempering effect, reduce the brittleness of the material, simultaneously be beneficial to infinitely expanding an austenite phase region and reduce the adverse effect of a steel plate coating component (such as Al element) in the welding process. Specifically, the welding wire may contain 0.01 to 0.08 wt% of Ti,0.01 to 0.06 wt% of Nb, and 0.01 to 0.1 wt% of Co, based on the total weight of the welding wire.

Further, the total content of Ti element and Nb element may be 0.02 to 0.1 wt%, more preferably 0.04 to 0.1 wt%, based on the total weight of the welding wire. The above range is advantageous for further improving the strength and hardness of the material.

Further, in the welding wire, the weight ratio of Zr element to Ti element is not less than 2.5. Through a large number of experiments, when the weight ratio of Zr element to Ti element meets the above conditions, the formed carbide is finer and dispersed, and has more excellent toughness improving effect.

In a preferred embodiment of the present disclosure, the welding wire contains 0.3 to 0.45 wt% of C,0.15 to 0.25 wt% of Si,1 to 2.8 wt% of Mn,0.1 to 0.4 wt% of Cr,0.03 to 0.1 wt% of Zr,0.01 to 0.08 wt% of Ti,0.01 to 0.06 wt% of Nb,0.01 to 0.1 wt% of Co, and the balance of Fe and unavoidable impurity elements, based on the total weight of the welding wire. The proportion is favorable for further improving the strength, hardness and toughness of the material.

The welding wire disclosed by the invention has excellent strength, hardness and toughness, can be prepared into the forms of welding wires, welding plates, welding powder and the like, has stronger universality and lower cost, can realize high-quality laser tailor-welding of high-strength level (such as 2000MPa level, 2200MPa level and the like) steel, and effectively inhibits the diffusion and aggregation of hydrogen in a welding seam, thereby reducing the formation probability of cracks, being suitable for producing other key industrial parts such as high-strength, high-safety and lightweight vehicle structural parts, ensuring the long-term stability and reliability of the structural parts, and meeting the industrial development demands.

A second aspect of the disclosure provides a method for manufacturing a laser splice welding structural member, the method comprising the steps of performing laser splice welding on two plated steel plates by using the welding wire according to the first aspect of the disclosure through a laser filler wire welding process to obtain a splice welded steel plate.

In a specific embodiment, the coated steel sheet is an Al-Si coated steel sheet, particularly an Al-Si coated steel sheet of high strength grade, and in particular, the tensile strength of the Al-Si coated steel sheet is not less than 2000MPa. The method is suitable for two plating steel plates with various strength and thickness combinations, and can comprise the combination of equal strength, unequal strength, equal thickness, unequal thickness and the like, and good welding quality can be realized. By way of example, the two plated steel sheets may include a first Al-Si plated steel sheet having a tensile strength of 2000MPa and a second Al-Si plated steel sheet having a tensile strength of 2200 MPa.

Further, the al—si plated steel sheet may include a substrate and a plating layer disposed on a surface of the substrate.

In one embodiment, the substrate may contain 0.27 to 0.39 wt% of C,0.1 to 0.6 wt% of Si,0.7 to 2.2 wt% of Mn,0.1 to 0.4 wt% of Al, not more than 0.1 wt% of P, not more than 0.1 wt% of S, not more than 0.7 wt% of Cr, not more than 0.01 wt% of B, not more than 0.16 wt% of Ti, not more than 0.1 wt% of Nb, not more than 0.3 wt% of V, and the balance Fe and unavoidable impurity elements, based on the total weight of the substrate.

The thickness of the substrate may be adjusted within a certain range, for example, may be 1 to 2.5mm.

The plating layer contains Al (aluminum) and Si (silicon), specifically, the plating layer may contain 80 to 95 wt% of Al,5 to 11 wt% of Si, and the balance of Fe and unavoidable impurity elements, based on the total weight of the plating layer.

The thickness of the plating layer may be adjusted within a certain range, for example, may be 6 to 19 μm.

The operation condition of the laser tailor-welding can be adjusted in a larger range, and the welding wire provided by the disclosure can be particularly well adapted to the butt joint gap change of the steel plates in a wider range. Specifically, the laser welding conditions can include a butt joint gap of 0-0.5 mm, a welding speed of 80-120 mm/s, a welding wire diameter of 0.8-1.2 mm and a wire feeding speed of 80-110 mm/s.

Further, the method can further comprise the step of carrying out hot stamping forming on the laser splice welded material. The hot stamping forming conditions can include a heating temperature of 880-930 ℃, a heating time of 200-480 s, a quenching cooling speed of 30-50 ℃ per second and a quenching cooling time of 15-40 s.

In a third aspect of the present disclosure, there is provided a laser tailor welded construction made by the method of the second aspect of the present disclosure.

The laser splice welded structure of the present disclosure has excellent strength, hardness and toughness, specifically, the yield strength of the laser splice welded structure may be not less than 1200MPa, preferably not less than 1300MPa, the tensile strength may be not less than 1700MPa, preferably not less than 1900MPa, the elongation after break may be not less than 4.5%, preferably not less than 5%, and the weld hardness may be not less than 520Hv, preferably not less than 560Hv.

The laser splice welding structural member comprises a steel plate area and a welding area, wherein the welding area is formed by the welding wire, the microstructure of the welding area is a martensitic structure, and the microstructure of the welding area endows the welding area with extremely high hardness and strength, so that the reliability of the laser splice welding structural member in high-strength application is ensured. In addition, in the tensile test, the fracture position of the laser splice welded structural member occurs in the steel plate area (namely, the base material area) instead of the welding area, and the result shows that the strength of the welding area is higher than that of the steel plate area, and the whole laser splice welded structural member shows excellent mechanical property and stability in practical application.

A fourth aspect of the present disclosure provides a vehicle comprising the laser tailor welded structure of the third aspect of the present disclosure.

In one embodiment, the vehicle includes a door ring made from the laser tailor welded structure. The specific structure of the door ring may be conventional in the art and may include, for example, an a-pillar, a B-pillar, a rocker, an a-pillar roof rail, a B-pillar roof rail, and other connectors. The laser splice welding structural member is used for manufacturing the door ring, is used as an important part of a vehicle body, can play a key role in protecting the safety of drivers and passengers in the vehicle when the vehicle body is impacted, especially when the vehicle body is impacted in a small offset manner and in a side impact manner, and remarkably improves the safety performance of the vehicle.

The present disclosure is further illustrated in detail by the following examples.

Example 1

The welding wire of this example has the chemical composition of 0.33 wt% of C,0.21 wt% of Si,1.58 wt% of Mn,0.02 wt% of Ti,0.031 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Example 2

The welding wire of this example had chemical composition of 0.33 wt% of C,0.21 wt% of Si,1.58 wt% of Mn,0.03 wt% of Ti,0.013 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Example 3

The welding wire of this example has the chemical composition of 0.33 wt% of C,0.21 wt% of Si,1.58 wt% of Mn,0.01 wt% of Ti,0.02 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Example 4

The welding wire of this example has the chemical composition of 0.27 wt% of C,0.21 wt% of Si,1.58 wt% of Mn,0.02 wt% of Ti,0.031 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Example 5

The welding wire of this example has the chemical composition of 0.33 wt% of C,0.11 wt% of Si,1.58 wt% of Mn,0.02 wt% of Ti,0.031 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Example 6

The welding wire of this example has the chemical composition of 0.33 wt% of C,0.21 wt% of Si,1.58 wt% of Mn,0.02 wt% of Ti,0.031 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr, and the balance of Fe and unavoidable impurity elements.

Example 7

The welding wire of this example has the chemical composition of 0.33 wt% of C,0.21 wt% of Si,0.8 wt% of Mn,0.02 wt% of Ti,0.031 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Example 8

The welding wire of this example has the chemical composition of 0.33 wt% of C,0.21 wt% of Si,1.58 wt% of Mn,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Comparative example 1

The welding wire of this comparative example had chemical composition of 0.22 wt% of C,0.21 wt% of Si,1.58 wt% of Mn,0.03 wt% of Ti,0.031 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Comparative example 2

The welding wire of this comparative example had chemical composition of 0.33 wt% of C,0.21 wt% of Si,0.61 wt% of Mn,0.03 wt% of Ti,0.031 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Comparative example 3

The welding wire of this comparative example had chemical composition of 0.33 wt% of C,0.21 wt% of Si,1.58 wt% of Mn,0.03 wt% of Ti,0.031 wt% of Nb,0.22 wt% of Cr,0.02 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Comparative example 4

The welding wire of this comparative example had chemical composition of 0.33 wt% of C,0.44 wt% of Si,1.58 wt% of Mn,0.03 wt% of Ti,0.031 wt% of Nb,0.22 wt% of Cr,0.06 wt% of Zr,0.03 wt% of Co, and the balance of Fe and unavoidable impurity elements.

Comparative example 5

The welding wire of this comparative example had chemical composition of 0.22 wt% of C,0.25 wt% of Si,1.24 wt% of Mn,0.03 wt% of Ti,0.17 wt% of Cr,0.045 wt% of Al, and the balance of Fe and unavoidable impurity elements.

Comparative example 6

The welding wire of this comparative example had chemical composition of 0.24 wt% of C,0.01 wt% of Si,1.43 wt% of Mn,0.02 wt% of Ti,0.012 wt% of Nb,0.23 wt% of Cr,0.003 wt% of N,6.7 wt% of Ni,0.035 wt% of Al, and the balance of Fe and unavoidable impurity elements.

Comparative example 7

The welding wire of this comparative example had chemical composition of 0.04 wt% of C,0.25 wt% of Si,1.54 wt% of Mn,0.17 wt% of W,0.05 wt% of Nb,0.2 wt% of Cr,0.8 wt% of Mo,4.05 wt% of Ni,0.14 wt% of Cu, and the balance of Fe and unavoidable impurity elements.

Comparative example 8

The welding wire of this comparative example had chemical composition of 0.2 wt% of C,0.35 wt% of Si,2.31 wt% of Mn,0.025 wt% of Nb,2.24 wt% of Cr,4.11 wt% of Ni, and the balance of Fe and unavoidable impurity elements.

Table 1 shows the components (unit, wt%) of the welding wires of examples 1 to 8 and comparative examples 1 to 8.

TABLE 1

Examples 9 to 16

The welding wires of the embodiments 1-8 are adopted to prepare a laser welding structural member, and the specific steps are that two Al-Si plated steel plates are subjected to laser welding under the conditions that the butt joint gap of the steel plates is 0.3mm, the welding speed is 100mm/s, the diameter of the welding wire is 1.0mm, the wire feeding speed is 100mm/s, the welding steel plates are obtained, then the welding steel plates are heated in a 900 ℃ roller hearth furnace for 380s, quenched at the cooling speed of 40 ℃/s, the quenching cooling time is 20s, and the welding steel plates are cooled to below 300 ℃ in a die, so that the laser welding structural member is obtained.

In the Al-Si plated steel sheet, the substrate composition (except Fe and unavoidable impurity elements), the thickness and the tensile strength are shown in Table 2 (unit, wt%), the plating composition was 88 wt% of Al,9 wt% of Si, the balance being Fe and unavoidable impurity element components, and the plating thickness was 10. Mu.m.

Comparative examples 9 to 16

Laser splice welded structural members were prepared in the same manner as in example 9 using the welding wires of comparative examples 1 to 8.

TABLE 2

Test example 1

Weld metallographic detection and performance detection are carried out on the laser splice welding structural members prepared in examples 9-16 and comparative examples 9-16, and specific results are shown in Table 3.

The metallographic detection method is a GB/T13298 metal microstructure detection method. The golden phase diagram of the welding area of the laser splice welded structure of example 9 is shown in fig. 1, and it can be seen that the microstructure of the welding area (i.e. the weld) is all martensitic structure, and the golden phase diagrams of the welding area of the laser splice welded structure of examples 10-16 are similar to those of fig. 1.

The test method of the tensile fracture mechanical property is GB/T228.1 part 1 of the tensile test of the metal material, namely a room temperature test method. The tensile fracture test results of the laser splice welded structure of example 9 are shown in FIG. 2, and it can be seen that the fracture site occurs in the steel plate region (i.e., the base material region) on the left side of the welded region (i.e., the weld), and the tensile fracture test photographs of the laser splice welded structures of examples 10 to 16 are similar to those of FIG. 2.

The hardness test method is GB/T4340.1 part 1 of the Vickers hardness test of the metal material, namely the test method. As shown in fig. 3, the hardness distribution test result of the laser tailor welded structure of example 1 shows that the hardness distribution of the welded zone (i.e., the weld) is 574 to 598 Hv, and the hardness distribution of the low-strength steel plate zone (i.e., the base material zone) is 563 to 569Hv.

TABLE 3 Table 3

In table 3, F represents that the weld microstructure type is ferrite, and M represents that the weld microstructure type is martensite.

As can be seen from table 3, the laser tailor welded constructions prepared using the welding wire of the present disclosure exhibit higher tensile strength, yield strength, elongation after break, and minimum hardness of the weld.

Test example 2

The laser splice welding structural members prepared in example 1 and comparative example 1 were subjected to a hydrogen induced delayed cracking test by using a four-point bending method to determine stress corrosion cracking resistance of metals and alloys in GB/T40403-2021 corrosion, and the stress level of the test sample was selected to be 100% yield strength and stored in an air medium at 15-30 ℃. The specific results are shown in Table 4.

TABLE 4 Table 4

As can be seen from table 4, the laser tailor welded constructions prepared using the welding wire of the present disclosure exhibit more excellent hydrogen induced delayed cracking performance.

The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, but the present disclosure is not limited to the specific details of the embodiments described above, and various simple modifications may be made to the technical solutions of the present disclosure within the scope of the technical concept of the present disclosure, and all the simple modifications belong to the protection scope of the present disclosure.

In addition, the specific features described in the foregoing embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, the present disclosure does not further describe various possible combinations.

Moreover, any combination between the various embodiments of the present disclosure is possible as long as it does not depart from the spirit of the present disclosure, which should also be construed as the disclosure of the present disclosure.

Claims

1. A welding wire is characterized by comprising 0.26-0.48 wt% of C, 0.1-0.3 wt% of Si, 0.8-3 wt% of Mn, 0.1-0.4 wt% of Cr, 0.03-0.1 wt% of Zr, 0.01-0.08 wt% of Ti, 0.01-0.06 wt% of Nb and 0.01-0.1 wt% of Co, and the balance of Fe and unavoidable impurity elements, wherein the total content of Ti elements and Nb elements is 0.02-0.1 wt% based on the total weight of the welding wire.

2. The welding wire claimed in claim 1, wherein a weight ratio of Zr element to Ti element in the welding wire is not less than 2.5.

3. The welding wire according to claim 1 or 2, wherein the welding wire contains 0.3 to 0.45 wt% of C,0.15 to 0.25 wt% of Si,1 to 2.8 wt% of Mn,0.1 to 0.4 wt% of Cr,0.03 to 0.1 wt% of Zr,0.01 to 0.08 wt% of Ti,0.01 to 0.06 wt% of Nb,0.01 to 0.1 wt% of Co, and the balance of Fe and unavoidable impurity elements, based on the total weight of the welding wire.

4. A method for preparing a laser splice welding structural member is characterized by comprising the step of carrying out laser splice welding on two plated steel plates by adopting the welding wire according to any one of claims 1-3 through a laser filler wire welding process to obtain a splice welding steel plate.

5. The method according to claim 4, wherein the plated steel sheet is an Al-Si plated steel sheet having a tensile strength of not less than 2000MPa.

6. The method of claim 5, wherein the Al-Si plated steel sheet comprises a substrate and a plating layer provided on a surface of the substrate.

7. The method according to claim 6, wherein the substrate contains 0.27 to 0.39 wt% of C,0.1 to 0.6 wt% of Si,0.7 to 2.2 wt% of Mn,0.1 to 0.4 wt% of Al, not more than 0.1 wt% of P, not more than 0.1 wt% of S, not more than 0.7 wt% of Cr, not more than 0.01 wt% of B, not more than 0.16 wt% of Ti, not more than 0.1 wt% of Nb, not more than 0.3 wt% of V, the balance being Fe and unavoidable impurity elements based on the total weight of the substrate, and/or,

8. The method according to claim 6, wherein the thickness of the plating layer is 6-19 μm and/or the thickness of the substrate is 1-2.5 mm.

9. The method of claim 4, wherein the laser splice welding conditions include a butt gap of 0-0.5 mm, a welding speed of 80-120 mm/s, a wire diameter of 0.8-1.2 mm, and a wire feed speed of 80-110 mm/s.

10. The method of claim 4, further comprising hot stamping the tailor welded blank to form a laser tailor welded construction.

11. The method of claim 10, wherein the hot stamping forming conditions comprise a heating temperature of 880-930 ℃, a heating time of 200-480 s, a quenching cooling speed of 30-50 ℃ per second, and a quenching cooling time of 15-40 s.

12. A laser tailor welded construction made by the method of any one of claims 4 to 11.

13. The laser tailor welded structure of claim 12 wherein the yield strength of the laser tailor welded structure is not less than 1200MPa, the tensile strength is not less than 1700MPa, the elongation after break is not less than 4.5%, and the weld hardness is not less than 520Hv.

14. A vehicle comprising the laser tailor welded structure of claim 12 or 13.