A dissimilar metal laser welding method for titanium alloy and stainless steel

Abstract

The invention discloses a dissimilar metal laser welding method of titanium alloy and stainless steel, belonging to the field of metal welding technology. Specifically, the following steps are included: step S1: material preparation, preparing titanium alloy plate, stainless steel plate, bronze plate and nickel-based high-temperature alloy plate; step S2: polishing and cleaning, polishing and cleaning titanium alloy plate, stainless steel plate, bronze plate and nickel-based high-temperature alloy plate; step S3: arranging and placing, arranging titanium alloy plate, stainless steel plate, bronze plate and nickel-based high-temperature alloy plate in the order of titanium alloy plate-bronze plate-nickel-based high-temperature alloy plate-stainless steel plate; step S4: welding, step S41: welding bronze plate and nickel-based high-temperature alloy plate; step S42: welding titanium alloy plate and part of bronze plate; step S43: welding nickel-based high-temperature alloy plate and stainless steel plate. The strength of the welding joint between titanium alloy plate and stainless steel plate is high.

Description

Technical Field

[0001] The invention relates to the technical field of metal welding, and in particular to a dissimilar metal laser welding method of titanium alloy and stainless steel. Background Art

[0002] Titanium alloy and stainless steel are both important engineering metal materials, which are widely used in various industrial fields, especially in high-tech fields such as aerospace. With the development of science and technology, the requirements for the performance of product parts are becoming more and more stringent, and a single material (titanium alloy plate or stainless steel plate) can no longer meet the requirements of performance. However, when welding titanium alloy and stainless steel, brittle Ti-Fe intermetallic compounds (for example, TiFe, TiFe2 and other intermetallic compounds) are easily generated at the welded joints of titanium alloy and stainless steel, thereby reducing the welding mechanical properties of titanium alloy and stainless steel.

[0003] In order to solve the brittle Ti-Fe intermetallic compounds produced by titanium alloy and stainless steel, researchers added Cu foil as an intermediate metal transition layer between titanium alloy and stainless steel. The infinite mutual dissolution of titanium alloy and Cu foil in liquid state and solidification will form a less brittle titanium alloy bronze weld area, thereby improving the welding mechanical properties of titanium alloy and stainless steel. Through tensile specimen testing, the tensile strength between titanium alloy and stainless steel is 286MPa. However, the strength of the welded joint of titanium alloy and stainless steel is still relatively low, which is difficult to meet some higher strength requirements in practical applications. Summary of the invention

[0004] Based on this, it is necessary to provide a dissimilar metal laser welding method of titanium alloy and stainless steel with a higher strength of the weld joint of titanium alloy and stainless steel.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for laser welding dissimilar metals of titanium alloy and stainless steel, comprising the following steps:

[0006] Step S1: preparing materials, including preparing titanium alloy plates, stainless steel plates, bronze plates and nickel-based high-temperature alloy plates;

[0007] Step S2: polishing and cleaning, polishing and cleaning the titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate, so as to obtain clean titanium alloy plates, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate;

[0008] Step S3: arranging and placing the titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate whose surfaces have been polished and cleaned in a certain order, wherein the arrangement order is titanium alloy plate-bronze plate-nickel-based high-temperature alloy plate-stainless steel plate, and ensuring that the gap between each material is less than 0.1 mm;

[0009] Step S4: welding, laser welding is performed on the arranged titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate. The welding sequence is performed in the following three steps, namely:

[0010] Step S41: laser welding is performed on the interface between the bronze plate and the nickel-based high-temperature alloy plate, with the gap between the bronze plate and the nickel-based high-temperature alloy plate as the origin, the first laser beam is offset toward the nickel-based high-temperature alloy plate, the offset is S1, 0.1≤S1≤0.4, and laser welding is performed after the offset;

[0011] Step S42: laser welding is performed on the interface between the titanium alloy plate and the bronze plate, with the gap between the titanium alloy plate and the bronze plate as the origin, and the second laser beam is offset toward the bronze plate side, the offset is S2, 0.1≤S2≤0.4, and laser welding is performed after the offset;

[0012] Step S43: laser welding is performed on the interface between the nickel-based high-temperature alloy plate and the stainless steel plate. The gap between the nickel-based high-temperature alloy plate and the stainless steel plate is used as the origin. The third laser beam is offset toward the stainless steel plate. The offset is S3, 0.1≤S3≤0.4. Laser welding is performed after the offset.

[0013] Further, in step S41, the offset amount S1 of the first laser beam toward the nickel-based high-temperature alloy plate side is 0.3 mm.

[0014] Further, in step S42, the offset amount of the second laser beam toward the bronze plate side is S2 = 0.2 mm.

[0015] Further, in step S43, the offset amount S3 of the third laser beam toward the stainless steel plate side is 0.3 mm.

[0016] Furthermore, the parameters of the welding process in step S41 are: power of 2600 W, spot diameter of 0.4 mm, welding speed of 2100 mm / min, shielding gas of Ar=12 L / min, powder feeding gas of He=8 L / min, and defocus amount=-3 mm.

[0017] Furthermore, the parameters of the welding process in step S42 are: power of 3500 W, spot diameter of 0.4 mm, welding speed of 2100 mm / min, shielding gas of Ar=12 L / min, powder feeding gas of He=8 L / min, and defocus amount=-3 mm.

[0018] Furthermore, the parameters of the welding process in step S43 are: power of 3500 W, spot diameter of 0.4 mm, welding speed of 2100 mm / min, shielding gas of Ar=12 L / min, powder feeding gas of He=8 L / min, and defocus amount=-3 mm.

[0019] Furthermore, the titanium alloy plate is made of TC4 titanium alloy material, the stainless steel plate is made of 304 stainless steel material, the bronze plate is made of nickel aluminum bronze material, and the nickel-based high temperature alloy plate is made of inconel 625 material.

[0020] Furthermore, in step S2, the surfaces to be welded of the titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate are polished using sandpaper, and then the polished surfaces are wiped with alcohol and dried with cold air to prevent impurities from being introduced into the surfaces of the titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate.

[0021] The beneficial effects of the present invention are as follows: the dissimilar metal laser welding method of titanium alloy and stainless steel provided by the present invention performs laser welding on the interface between the titanium alloy plate and the bronze plate, and the unmelted portion of the bronze plate forms an unmelted bronze area, which can prevent the diffusion of Ti elements and Fe elements. At the same time, the nickel-based high-temperature alloy plate has good plasticity and ductility, and the nickel-based high-temperature alloy plate can be infinitely soluble in the stainless steel plate and the bronze plate without generating intermetallic compounds, thereby not causing adverse effects on the nickel-based high-temperature alloy plate and the stainless steel plate and the bronze plate. Compared with the prior art, the strength of the welding joint between the titanium alloy plate and the stainless steel plate is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] Figure 1 It is a flow chart of the dissimilar metal laser welding method of titanium alloy and stainless steel of the present invention;

[0024] Figure 2 yes Figure 1 The schematic diagram of the structure of the arrangement of various test plates in the welding of titanium alloy and stainless steel metal is shown;

[0025] Figure 3 yes Figure 2The structural schematic diagram of the welding position in the welding of titanium alloy and stainless steel metal is shown;

[0026] Figure 4 yes Figure 2 The microstructural morphology of the welding of titanium alloy and stainless steel metal is shown.

[0027] The names and numbers of the parts in the figure are:

[0028] Titanium alloy plate 1 Stainless steel plate 2 Bronze plate 3

[0029] Nickel-based high-temperature alloy plate 4 Titanium alloy weld Bronze area A Bronze unmelted area B

[0030] Nickel-based high-temperature alloy weld area Stainless steel weld area D The first laser beam 5-1

[0031] Domain C

[0032] The second laser beam 5-2 The third laser beam 5-3 DETAILED DESCRIPTION

[0033] The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the present invention in a schematic manner, and therefore only shows the components related to the present invention.

[0034] See also Figures 1 to 4 The present invention provides a method for laser welding dissimilar metals of titanium alloy and stainless steel, which specifically comprises the following steps:

[0035] Step S1: prepare materials, prepare a titanium alloy plate 1, a stainless steel plate 2, a bronze plate 3 and a nickel-based high-temperature alloy plate 4. In this embodiment, the titanium alloy plate 1 is made of TC4 titanium alloy material, the stainless steel plate 2 is made of 304 stainless steel material, the bronze plate 3 is made of nickel-aluminum bronze material, and the nickel-based high-temperature alloy plate 4 is made of inconel 625 material.

[0036] Step S2: Polishing and cleaning: the titanium alloy plate 1, the stainless steel plate 2, the bronze plate 3 and the nickel-based high-temperature alloy plate 4 are polished with sandpaper, and then the polished surface is wiped with alcohol and blown dry with cold air to prevent impurities from being introduced into the surface of the titanium alloy plate 1, the stainless steel plate 2, the bronze plate 3 and the nickel-based high-temperature alloy plate 4, thereby obtaining a clean titanium alloy plate 1, the stainless steel plate 2, the bronze plate 3 and the nickel-based high-temperature alloy plate 4.

[0037] Step S3: Arrange and place the titanium alloy plate 1, the stainless steel plate 2, the bronze plate 3 and the nickel-based high-temperature alloy plate 4 whose surfaces have been polished and cleaned in a certain order, wherein the arrangement order is titanium alloy plate 1 - bronze plate 3 - nickel-based high-temperature alloy plate 4 - stainless steel plate 2, and ensure that the gap between each material is less than 0.1 mm.

[0038] Step S4: welding, laser welding is performed on the arranged titanium alloy plate 1, stainless steel plate 2, bronze plate 3 and nickel-based high temperature alloy plate 4, and the welding sequence is performed according to the following three steps, namely:

[0039] Step S41: laser welding is performed on the interface between the bronze plate 3 and the nickel-based high-temperature alloy plate 4. Specifically, the first laser beam 5-1 is offset toward the nickel-based high-temperature alloy plate 4 with the gap between the bronze plate 3 and the nickel-based high-temperature alloy plate 4 as the origin. The offset is S1 (unit: mm), where 0.1≤S1≤0.4. Laser welding is performed after the offset. In this embodiment, S1=0.3 mm, so that the bronze plate 3 and the nickel-based high-temperature alloy plate 4 form a nickel-based high-temperature alloy weld area C. The bronze plate 3 and the nickel-based high-temperature alloy plate 4 are infinitely soluble in each other and do not generate intermetallic compounds, so that no adverse effects are caused between the bronze plate 3 and the nickel-based high-temperature alloy plate 4.

[0040] Among them, the parameters of the welding process in step S41 are: power is 2600 W, spot diameter is 0.4 mm, welding speed is 2100 mm / min, shielding gas is Ar=12 L / min, powder feeding gas is He=8 L / min, and defocus amount=-3 mm.

[0041] Step S42: laser welding is performed on the interface between the titanium alloy plate 1 and the bronze plate 3. Specifically, the gap between the titanium alloy plate 1 and the bronze plate 3 is taken as the origin, and the second laser beam 5-2 is offset to the bronze plate 3 side, and the offset is S2 (unit: mm), wherein 0.1≤S2≤0.4. Laser welding is performed after the offset. In this embodiment, S2=0.2 mm, so that part of the bronze plate 3 and the titanium alloy plate 1 form a titanium alloy weld bronze region A, and the unmelted part of the bronze plate 3 forms an unmelted bronze region B. The brittleness of the Ti-Cu intermetallic compound in the titanium alloy weld bronze region A is less than that of the Ti-Fe intermetallic compound, and the plasticity and ductility of bronze are relatively good, which can play a role in coordinated deformation, thereby reducing the welding stress generated when the weld joint between the titanium alloy plate 1 and the bronze plate 3 is deformed, and further improving the mechanical properties of the weld joint between the titanium alloy plate 1 and the bronze plate 3. The unmelted bronze area B is located between the titanium alloy plate 1 and the stainless steel plate 2, so that the Ti element in the titanium alloy plate 1 and the Fe element in the stainless steel plate 2 are isolated from each other, and the Ti element in the titanium alloy plate 1 and the Fe element in the stainless steel plate 2 will not diffuse and react with each other, thereby preventing the formation of brittle TiFe and TiFe2 intermetallic compounds.

[0042] Among them, the parameters of the welding process in step S42 are: power is 3500 W, spot diameter is 0.4 mm, welding speed is 2100 mm / min, shielding gas is Ar=12 L / min, powder feeding gas is He=8 L / min, and defocus amount=-3 mm.

[0043] Step S43: Laser welding is performed on the interface between the nickel-based high-temperature alloy plate 4 and the stainless steel plate 2. Specifically, the gap between the nickel-based high-temperature alloy plate 4 and the stainless steel plate 2 is taken as the origin, and the third laser beam 5-3 is offset to the stainless steel plate 2 side by S3 (unit: mm), wherein 0.1≤S3≤0.4. Laser welding is performed after the offset. In this embodiment, S3=0.3 mm, so that the nickel-based high-temperature alloy plate 4 and the stainless steel plate 2 form a stainless steel weld area D. The nickel-based high-temperature alloy plate 4 has good plasticity and ductility, and the melting point of the nickel-based high-temperature alloy plate 4 is very close to that of the stainless steel plate 2. The nickel-based high-temperature alloy plate 4 and the stainless steel plate 2 can be infinitely soluble in each other and no intermetallic compound is generated, so that the nickel-based high-temperature alloy plate 4 and the stainless steel plate 2 will not have adverse effects.

[0044] Among them, the parameters of the welding process in step S43 are: power is 3500W, spot diameter is 0.4mm, welding speed is 2100mm / min, shielding gas is Ar=12L / min, powder feeding gas is He=8L / min, and defocus amount=-3mm.

[0045] The present invention conducts a tensile test on the welded sample, as shown in Table 1.

[0046] Table 1 Mechanical properties of dissimilar metal laser welding of titanium alloy / stainless steel

[0047]

[0048] From the test results in Table 1, it can be found that when a specimen is cut into two specimens, the tensile strength of specimen 1 is 338 MPa, and the elongation after fracture is 2.5%; the tensile strength of specimen 2 is 316 MPa, and the elongation after fracture is 1.5%. The tensile strengths of the above specimens 1 and 2 are both greater than 286 MPa. It can be seen that the tensile strengths of the above specimens 1 and 2 are higher than the tensile strength of the Cu foil as the intermediate layer metal in the prior art, and thus the welding mechanical properties of the titanium alloy and the stainless steel are better.

[0049] The dissimilar metal laser welding method of titanium alloy and stainless steel provided by the present invention performs laser welding on the interface of the titanium alloy plate 1 and the bronze plate 3, and the unmelted portion of the bronze plate 3 forms an unmelted bronze area B, which can prevent the diffusion of Ti elements and Fe elements. At the same time, the nickel-based high-temperature alloy plate 4 has good plasticity and ductility, and the nickel-based high-temperature alloy plate 4 and the stainless steel plate 2 and the bronze plate 3 can be infinitely soluble in each other without generating intermetallic compounds, thereby preventing the nickel-based high-temperature alloy plate 4 from causing adverse effects on the stainless steel plate 2 and the bronze plate 3. Compared with the prior art, the strength of the welding joint between the titanium alloy plate and the stainless steel plate is higher.

[0050] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the scope of the present invention through the above description. The technical scope of this invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for laser welding dissimilar metals of titanium alloy and stainless steel, characterized in that: The following steps are involved: Step S1: preparing materials, including preparing titanium alloy plates, stainless steel plates, bronze plates and nickel-based high-temperature alloy plates; Step S2: polishing and cleaning, polishing and cleaning the titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate, so as to obtain clean titanium alloy plates, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate; Step S3: arranging and placing the titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate whose surfaces have been polished and cleaned in a certain order, wherein the arrangement order is titanium alloy plate-bronze plate-nickel-based high-temperature alloy plate-stainless steel plate, and ensuring that the gap between each material is less than 0.1 mm; Step S4: welding, laser welding is performed on the arranged titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate. The welding sequence is performed in the following three steps, namely: Step S41: laser welding is performed on the interface between the bronze plate and the nickel-based high-temperature alloy plate, with the gap between the bronze plate and the nickel-based high-temperature alloy plate as the origin, the first laser beam is offset toward the nickel-based high-temperature alloy plate, the offset is S1, 0.1 mm ≤ S1 ≤ 0.4 mm, and laser welding is performed after the offset; Step S42: laser welding is performed on the interface between the titanium alloy plate and the bronze plate. With the gap between the titanium alloy plate and the bronze plate as the origin, a second laser beam is offset toward the bronze plate side by an offset amount of S2, 0.1 mm ≤ S2 ≤ 0.4 mm. After the offset, laser welding is performed so that a portion of the bronze plate and the titanium alloy plate form a titanium alloy weld bronze region, and a portion of the bronze plate that has not melted forms an unmelted bronze region. Step S43: laser welding is performed on the interface between the nickel-based high-temperature alloy plate and the stainless steel plate. The gap between the nickel-based high-temperature alloy plate and the stainless steel plate is used as the origin. The third laser beam is offset toward the stainless steel plate. The offset is S3, 0.1 mm ≤ S3 ≤ 0.4 mm. Laser welding is performed after the offset.

2. The dissimilar metal laser welding method of titanium alloy and stainless steel according to claim 1, characterized in that: In step S41, the offset amount S1 of the first laser beam toward the nickel-based high-temperature alloy plate side is 0.3 mm.

3. The dissimilar metal laser welding method of titanium alloy and stainless steel as claimed in claim 2, characterized in that: In step S42, the second laser beam is offset toward the bronze plate by an amount S2 = 0.2 mm.

4. The dissimilar metal laser welding method of titanium alloy and stainless steel as claimed in claim 3, characterized in that: In step S43, the third laser beam is offset toward the stainless steel plate by an amount S3 = 0.3 mm.

5. The dissimilar metal laser welding method of titanium alloy and stainless steel as claimed in claim 1, characterized in that: The parameters of the welding process in step S41 are: power of 2600 W, spot diameter of 0.4 mm, welding speed of 2100 mm / min, shielding gas of Ar=12 L / min, powder feeding gas of He=8 L / min, and defocus amount=-3 mm.

6. The dissimilar metal laser welding method of titanium alloy and stainless steel as claimed in claim 5, characterized in that: The parameters of the welding process in step S42 are: power of 3500 W, spot diameter of 0.4 mm, welding speed of 2100 mm / min, shielding gas of Ar=12 L / min, powder feeding gas of He=8 L / min, and defocus amount=-3 mm.

7. The dissimilar metal laser welding method of titanium alloy and stainless steel according to claim 6, characterized in that: The parameters of the welding process in step S43 are: power of 3500 W, spot diameter of 0.4 mm, welding speed of 2100 mm / min, shielding gas of Ar=12 L / min, powder feeding gas of He=8 L / min, and defocus amount=-3 mm.

8. The dissimilar metal laser welding method of titanium alloy and stainless steel as claimed in claim 1, characterized in that: The titanium alloy plate is made of TC4 titanium alloy material, the stainless steel plate is made of 304 stainless steel material, the bronze plate is made of nickel aluminum bronze material, and the nickel-based high temperature alloy plate is made of inconel625 material.

9. The dissimilar metal laser welding method of titanium alloy and stainless steel as claimed in claim 1, characterized in that: In step S2, the surfaces to be welded of the titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate are polished with sandpaper, and then the polished surfaces are wiped with alcohol and dried with cold air to prevent impurities from being introduced into the surfaces of the titanium alloy plate, the stainless steel plate, the bronze plate and the nickel-based high-temperature alloy plate.

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