Welding wire and welding process thereof

Abstract

The invention belongs to the technical field of welding, and particularly relates to a welding wire and a welding process thereof. In particular to a welding wire which is prepared from the following components in parts by weight: 0.2 to 0.9 part of Mo, 0 to 10 parts of Ni, 1.5 to 6 parts of Mn, 0 to 6 parts of Cr, 0.02 to 0.06 part of C, 0.5 to 0.8 part of Si, 0.01 to 0.06 part of P and 0.002 to 0.005 part of S. The components of the welding wire are optimized, multiple metal elements are matched, the proportion of all the elements is optimized, and the elements are molten into a welding seam in the welding process, so that the influence of the aluminum element is reduced, the metal components of a molten pool are adjusted, and a welding seam joint with good performance is formed.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to a welding wire and a welding process thereof. Background Art

[0002] In recent years, China's automotive industry has developed rapidly, and consumers have placed increasingly higher demands on automobiles. Range, lightweighting, and safety are key technological innovations. Hot-formed steel plates, due to their excellent performance and characteristics, are increasingly being used in automotive body parts. They can not only reduce weight but also withstand greater loads and impact forces, especially in safety structural parts such as automobile A-pillars, B-pillars, and door rings.

[0003] In order to prevent oxidation and carbonization during the subsequent processing of hot-formed steel plates, a layer of aluminum-silicon alloy is often coated on their surface. The aluminum component in the coating is easily mixed into the weld during welding, which greatly reduces the mechanical properties of the weld. In order to avoid performance degradation, it is necessary to reduce the impact of aluminum on the weld. This has always been a technical difficulty that has plagued the stable and qualified production of laser welding of aluminum-silicon coated plates.

[0004] Some companies in the market use lasers to strip the surface coating of hot-formed steel plates, or use steel brushes to eliminate the impact of aluminum on welds. This method requires an additional stripping process. The equipment for the stripping process is expensive, has high maintenance costs, and is not competitive in the market.

[0005] The existing welding wires on the market are often high in nickel content, which can reduce the formation of brittle intermetallic compounds in the weld. The high nickel content is expensive. Some companies also use welding wires with high molybdenum content, which will lead to a significant increase in costs. As a production consumable, reducing its cost is urgent.

[0006] The existing welding wires on the market have very strict requirements for the gap reserved for tailor-welded blanks during laser wire welding. This is due to the limitations of the welding wire composition and the process method itself, which puts higher requirements on the equipment. In particular, the welding fixtures for reserving gaps are expensive, difficult to debug, and have poor production process stability. Summary of the Invention

[0007] In order to solve the above problems, the present invention provides the following solutions:

[0008] The welding wire is composed of the following components in parts by weight:

[0009] Mo is 0.2~0.9 parts,

[0010] Ni is 0 to 10 parts,

[0011] Mn is 1.5 to 6 parts,

[0012] Cr is 0 to 6 parts,

[0013] C is 0.02 to 0.06 parts,

[0014] Si is 0.5 to 0.8 parts,

[0015] P is 0.01 to 0.06 parts,

[0016] S is 0.002 to 0.005 parts.

[0017] In some examples, the diameter of the welding wire is 0.8-1.6 mm.

[0018] In some examples, the welding wire has a yield strength ranging from 400 to 700 MPa and a tensile strength ranging from 400 to 800 MPa.

[0019] Application of any of the aforementioned welding wires in laser wire-filling welding.

[0020] In some embodiments, the application includes the following steps:

[0021] S1. Keep one end of any of the aforementioned welding wires in the gap between two base materials to be welded, wherein the base materials include at least a first plate and a second plate;

[0022] S2, using laser to melt the welding wire and the base material to be welded, and forming a weld seam after cooling;

[0023] S3. Heat the weld area to the hot forming temperature of the base material and then quench it at a rate of at least 40°C / s.

[0024] In some examples, the spacing between the first plate and the second plate is less than or equal to 10-20% of the thickness of the parent material.

[0025] This invention optimizes the welding wire composition, combining multiple metal elements in an optimized ratio. These elements melt into the weld during welding, reducing the impact of aluminum and regulating the composition of the molten pool metal to achieve a high-performance weld joint. The key metal elements regulated are C, Si, Mn, P, S, Mo, and Ni. By utilizing specialized welding wire and laser welding process parameters, aluminum-silicon coated thermoformed steel sheets can be welded without requiring a gap. Optimizing process parameters allows for stable welding of tailor-welded sheets with gaps between 0 and 0.3 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the welding application state of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below.

[0028] The welding wire is composed of the following components in parts by weight:

[0029] Mo is 0.2~0.9 parts,

[0030] Ni is 0 to 10 parts,

[0031] Mn is 1.5 to 6 parts,

[0032] Cr is 0 to 6 parts,

[0033] C is 0.02 to 0.06 parts,

[0034] Si is 0.5 to 0.8 parts,

[0035] P is 0.01 to 0.06 parts,

[0036] S is 0.002 to 0.005 parts.

[0037] In some examples, the diameter of the welding wire is 0.8-1.6 mm.

[0038] In some examples, the welding wire has a yield strength ranging from 400 to 700 MPa and a tensile strength ranging from 400 to 800 MPa.

[0039] The application of any of the aforementioned welding wires in laser welding with filler wire is subject to certain specific conditions: the wire feeding mechanism may use a cold wire or a hot wire device, the wire feeding speed may be selected to be 1 to 5 m / min, and the wire feeding angle may be selected to be 15 to 75 degrees.

[0040] In some embodiments, the application includes the following steps:

[0041] S1. Keep one end of any of the aforementioned welding wires in the gap between two base materials to be welded, wherein the base materials include at least a first plate and a second plate;

[0042] S2, using laser to melt the welding wire and the base material to be welded, and forming a weld seam after cooling;

[0043] S3. Heat the weld area to the hot forming temperature of the base material and then quench it at a rate of at least 40°C / s.

[0044] In some examples, the spacing between the first plate and the second plate is less than or equal to 10-20% of the thickness of the parent material; however, in actual application, the thickness of the two plates is not strictly required to be consistent, and errors may exist while meeting the requirements.

[0045] like Figure 1As shown in , during welding: an electromagnet clamp is used to clamp the first plate and the second plate respectively, so that the gap between the edges of the two plates to be welded is less than or equal to 10-20% of the plate thickness (depending on the plate thickness); a linear axis motion mechanism is used to drive the welding head, and the laser beam emitted by the welding head can be in a non-vibrating form or a vibrating form, and the vibration form can be in a spiral, Z-shaped or other forms. The vibration of the laser beam can improve the bridging ability and allow the welding wire and the base material to be fully and evenly combined; a laser wire filling welding process is used for the joint of the first plate and the second plate, and the welding wire and the base material are melted at the same time, so that the two are combined and condensed to form a weld, and the strength of the weld is then tested after welding; the welded product is placed in a heating furnace, heated to the hot forming temperature required by the base material itself, and then quenched at a cooling rate greater than 40 degrees / s, and then a tensile test is performed on the weld test plate. The joint breaks at the base material, indicating that the joint performance is not lower than that of the base material and meets the use requirements.

[0046] Using high-power laser wire-filling welding technology and special welding wire, there is no need to clean or ablate the surface of the aluminum-silicon coated plate. Direct welding can achieve welded joints with good mechanical properties. It is applicable to aluminum-silicon coated hot-formed steel from many mainstream steel mills on the market.

[0047] It will be apparent to those skilled in the art that various modifications to the above embodiments may be made without departing from the overall spirit and concept of the present invention. Such modifications fall within the scope of protection of the present invention. The protection scheme of the present invention shall be subject to the claims appended hereto.

Claims

1. Welding wire, characterized in that The welding wire is composed of the following components in parts by weight: Mo is 0.2 to 0.9 parts, Ni is 0 to 10 parts, Mn is 1.5 to 6 parts, Cr is 0 to 6 parts, C is 0.02 to 0.06 parts, Si is 0.5 to 0.8 parts, P is 0.01 to 0.06 parts, and S is 0.002 to 0.005 parts.

2. The welding wire according to claim 1, characterized in that The diameter of the welding wire is 0.8-1.6 mm.

3. The welding wire according to claim 1, wherein The yield strength of the welding wire is in the range of 400-700 MPa, and the tensile strength is in the range of 400-800 MPa.

4. Use of the welding wire according to any one of claims 1 to 3 in laser filler wire welding.

5. The use according to claim 4, wherein: The application includes the following steps S1. Place one end of the welding wire according to any one of claims 1 to 3 in the gap between two base materials to be welded, wherein the base materials include at least a first plate and a second plate; S2, using laser to melt the welding wire and the base material to be welded, and forming a weld seam after cooling; S3. Heat the weld area to the hot forming temperature of the base material and then quench it at a rate of at least 40°C / s.

6. The use according to claim 4, wherein: The spacing between the first plate and the second plate is less than or equal to 10-20% of the thickness of the parent material.

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