阅读说明：本技术 钛-钢梯度复合材料cmt制备用过渡层焊丝及制备方法 (Transition layer welding wire for preparing titanium-steel gradient composite material CMT and preparation method ) 是由 褚巧玲 夏拓 张�林 张敏 赵鹏康 李继红 王锵 于 2021-08-19 设计创作，主要内容包括：本发明公开的钛-钢梯度复合材料CMT制备用过渡层焊丝,包括药芯和焊皮,其中药芯按质量百分比由以下组分组成：Cr粉10～20％,Ni粉10～20％,Nb粉10～20％,Co粉5～10％,剩余为Cu粉,以上组分质量百分比之和为100％。该药芯焊丝既可用于TIG焊,又可用于MIG焊,解决了钛-钢梯度复合材料的电弧增材直接制备问题。还提供了一种钛-钢梯度复合材料CMT制备用过渡层焊丝的制备方法。(The invention discloses a transition layer welding wire for preparing a titanium-steel gradient composite material CMT, which comprises a flux core and a welding skin, wherein the flux core consists of the following components in percentage by mass: 10-20% of Cr powder, 10-20% of Ni powder, 10-20% of Nb powder, 5-10% of Co powder and the balance of Cu powder, wherein the sum of the mass percentages of the components is 100%. The flux-cored wire can be used for TIG welding and MIG welding, and solves the problem of direct preparation of the titanium-steel gradient composite material by electric arc additive. Also provides a preparation method of the transition layer welding wire for preparing the titanium-steel gradient composite material CMT.)

1. The transition layer welding wire for preparing the titanium-steel gradient composite material CMT is characterized by comprising a flux core and a welding skin, wherein the flux core comprises the following components in percentage by mass: 10-20% of Cr powder, 10-20% of Ni powder, 10-20% of Nb powder, 5-10% of Co powder and the balance of Cu powder, wherein the sum of the mass percentages of the components is 100%.

2. The transition layer welding wire for preparing the titanium-steel gradient composite material CMT as claimed in claim 1, wherein the purity of Cr powder is not less than 99.9%, the purity of Ni powder is not less than 99.9%, the purity of Nb powder is not less than 99.9%, the purity of Co powder is not less than 99.9%, the purity of Cu powder is not less than 99.9%, and the particle sizes of 5 metal powders are all 100-200 meshes.

3. The transition layer welding wire for the preparation of titanium-steel gradient composite CMT of claim 1, wherein the welding skin is a copper strip, the thickness of the copper strip is 0.3mm, and the width of the copper strip is 7 mm.

4. The transitional layer welding wire for titanium-steel gradient Composite (CMT) production of claim 1, wherein the filling rate of the flux-cored powder in the welding wire is 25 wt.% to 30 wt.%.

5. The preparation method of the transition layer welding wire for preparing the titanium-steel gradient composite material CMT is characterized by comprising the following specific steps of:

step 1: respectively weighing 10-20% of Cr powder, 10-20% of Ni powder, 10-20% of Nb powder, 5-10% of Co powder and the balance of Cu powder according to mass percent, wherein the sum of the mass percentages of the components is 100%;

step 2: placing the Cr powder, the Ni powder, the Nb powder, the Co powder and the Cu powder weighed in the step 1 into a vacuum heating furnace for heating at the temperature of 150-200 ℃ for 1-2 h, and removing crystal water in the medicinal powder; placing the dried medicinal powder in a powder mixer for mixing for 30-40 min;

and step 3: a red copper strip is used as a welding skin, oil on the surface of the red copper strip is removed by adopting alcohol, the powder prepared in the step 2 is wrapped in the red copper strip by flux-cored wire drawing equipment, and the aperture of a first drawing grinding tool is 2.6 mm;

and 4, step 4: after the first process is finished, the aperture of a grinding tool is reduced in sequence for drawing, and the diameter of the finally obtained flux-cored wire is 1.2 mm;

and 5: and after the flux-cored wire is drawn, the flux-cored wire is wound on a wire reel through a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for later use.

6. The preparation method of the transition layer welding wire for preparing the titanium-steel gradient composite material CMT as claimed in claim 5, wherein the purity of Cr powder is more than or equal to 99.9%, the purity of Ni powder is more than or equal to 99.9%, the purity of Nb powder is more than or equal to 99.9%, the purity of Co powder is more than or equal to 99.9%, the purity of Cu powder is more than or equal to 99.9%, and the granularity of 5 metal powders is 100-200 meshes.

7. The method for preparing the transition layer welding wire for preparing the titanium-steel gradient composite material CMT as claimed in claim 5, wherein in the step 3, the red copper strip has a thickness of 0.3mm and a width of 7 mm.

8. The method for preparing a transition layer welding wire for preparing a titanium-steel gradient composite material CMT as claimed in claim 5, wherein the filling rate of the flux-cored powder in the welding wire is 25 wt.% to 30 wt.%.

Technical Field

The invention belongs to the technical field of metal material welding, and particularly relates to a transition layer welding wire for preparing a titanium-steel gradient composite material CMT (China Mobile technology for technology transfer), and a preparation method of the transition layer welding wire for preparing the titanium-steel gradient composite material CMT.

Background

The dissimilar metal connecting structure of titanium and steel has the characteristics of good corrosion resistance, high strength and the like, so that the dissimilar metal connecting structure has great application potential in the industrial departments of aerospace, energy power, petrochemical industry and the like. However, the difference in thermo-physical properties between titanium and steel is large, and brittle intermetallic compounds are easily formed, thereby deteriorating the connection properties of the joint. At present, research work aiming at titanium-steel dissimilar metal connection is carried out for more than 50 years, and the metal connection theory is developed into a plurality of advanced welding methods such as laser welding, electron beam welding, friction stir welding, brazing, diffusion welding, explosion welding, tungsten electrode argon arc welding, cold metal transition welding and the like. In practice, however, it is often difficult to join titanium-steel components with complex structures in practice, due to the limitations of the corresponding welding methods. Therefore, how to overcome the limitation of the titanium-steel connecting joint on the application structure is a problem to be solved when the titanium-steel connecting joint is popularized and applied to engineering.

The arc additive manufacturing technology, particularly the Cold Metal Transfer (CMT) technology can realize the preparation of structural parts with complex sizes, is simple and convenient to operate and high in adaptability, and becomes the most ideal choice for exploring the preparation of titanium-steel composite structures. However, due to the large difference in thermophysical properties between titanium and steel and the high susceptibility to brittle intermetallic compounds, it is important to develop a transition layer weld material for arc additive manufacturing of titanium-steel composite structures.

Disclosure of Invention

The invention aims to provide a transition layer welding wire for preparing a titanium-steel gradient composite material CMT, the flux-cored welding wire can be used for TIG welding and MIG welding, and the problem of direct preparation of electric arc additive of the titanium-steel gradient composite material is solved.

The invention also aims to provide a preparation method of the transition layer welding wire for preparing the titanium-steel gradient composite material CMT.

The technical scheme adopted by the invention is that the transition layer welding wire for preparing the titanium-steel gradient composite material CMT comprises a flux core and a welding skin, wherein the flux core comprises the following components in percentage by mass: 10-20% of Cr powder, 10-20% of Ni powder, 10-20% of Nb powder, 5-10% of Co powder and the balance of Cu powder, wherein the sum of the mass percentages of the components is 100%.

The present invention is also characterized in that,

the purity of Cr powder is more than or equal to 99.9 percent, the purity of Ni powder is more than or equal to 99.9 percent, the purity of Nb powder is more than or equal to 99.9 percent, the purity of Co powder is more than or equal to 99.9 percent, the purity of Cu powder is more than or equal to 99.9 percent, and the granularity of 5 metal powders is 100-200 meshes.

The welding skin is a red copper strip, the thickness of the red copper strip is 0.3mm, and the width of the red copper strip is 7 mm.

The filling rate of the flux-cored powder in the welding wire is 25-30 wt.%.

The invention adopts another technical scheme that the preparation method of the transition layer welding wire for preparing the titanium-steel gradient composite material CMT comprises the following specific steps:

step 1: respectively weighing 10-20% of Cr powder, 10-20% of Ni powder, 10-20% of Nb powder, 5-10% of Co powder and the balance of Cu powder according to mass percent, wherein the sum of the mass percentages of the components is 100%;

step 2: placing the Cr powder, the Ni powder, the Nb powder, the Co powder and the Cu powder weighed in the step 1 into a vacuum heating furnace for heating at the temperature of 150-200 ℃ for 1-2 h, and removing crystal water in the medicinal powder; placing the dried medicinal powder in a powder mixer for mixing for 30-40 min;

and step 3: a red copper strip is used as a welding skin, oil on the surface of the red copper strip is removed by adopting alcohol, the powder prepared in the step 2 is wrapped in the red copper strip by flux-cored wire drawing equipment, and the aperture of a first drawing grinding tool is 2.6 mm;

and 4, step 4: after the first process is finished, the aperture of a grinding tool is reduced in sequence for drawing, and the diameter of the finally obtained flux-cored wire is 1.2 mm;

and 5: and after the flux-cored wire is drawn, the flux-cored wire is wound on a wire reel through a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for later use.

The present invention is also characterized in that,

the purity of Cr powder is more than or equal to 99.9 percent, the purity of Ni powder is more than or equal to 99.9 percent, the purity of Nb powder is more than or equal to 99.9 percent, the purity of Co powder is more than or equal to 99.9 percent, the purity of Cu powder is more than or equal to 99.9 percent, and the granularity of 5 metal powders is 100-200 meshes.

In the step 3, the thickness of the red copper strip is 0.3mm, and the width is 7 mm.

The filling rate of the flux-cored powder in the welding wire is 25-30 wt.%.

The invention has the beneficial effects that:

(1) the flux-cored wire has a small diameter, the wire diameter is 1.2mm, and the flux-cored wire is widely applicable, and can be used for TIG welding and MIG welding;

(2) cu, Cr, Ni, Nb and Co are used as main components in the flux-cored wire, and when CMT is carried out to directly prepare a titanium-steel gradient composite structure, the alloy elements react with Ti and Fe elements of a matrix to form a plurality of compound phases, and a titanium-steel composite gradient layer is formed together. The transition layer welding wire is mainly made of Cu, and the formed gradient layer is mainly made of Cu-Ti intermetallic compounds and Cu-based solid solution. Wherein one side close to the steel is provided with a Cu-based solid solution and a Fe-based solid solution; one side close to the titanium is mainly CuTi₂，Cu₄Ti，Cu₃Ti₂An intermetallic compound. Cr and Ni elements play a role in adjusting the morphology and distribution of a Cu-Ti intermetallic compound in the gradient layer; the Nb and Co elements mainly play a role in improving the bonding strength between the gradient layer and Ti.

(3) The flux-cored wire has less alloy elements, simple preparation process and convenient large-scale batch production.

Drawings

FIG. 1 is a schematic view of a titanium-steel gradient composite structure of example 1;

FIG. 2 is a scanning electron microscope microstructure topography of a flux-cored wire prepared in embodiment 2 and deposited on a steel substrate;

FIG. 3 is a microstructure of a flux-cored wire prepared in embodiment 2 by a scanning electron microscope and deposited on a titanium substrate;

fig. 4 is a scanning electron microscope high-power microstructure morphology image of a ladder layer when the titanium-steel gradient composite material is prepared by the flux-cored wire prepared in the embodiment 2.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The transition layer welding wire for preparing the titanium-steel gradient composite material CMT comprises a flux core and a welding skin, wherein the flux core comprises the following components in percentage by mass: 10-20% of Cr powder, 10-20% of Ni powder, 10-20% of Nb powder, 5-10% of Co powder and the balance of Cu powder, wherein the sum of the mass percentages of the components is 100%.

The purity of Cr powder is more than or equal to 99.9 percent, the purity of Ni powder is more than or equal to 99.9 percent, the purity of Nb powder is more than or equal to 99.9 percent, the purity of Co powder is more than or equal to 99.9 percent, the purity of Cu powder is more than or equal to 99.9 percent, and the granularity of 5 metal powders is 100-200 meshes.

The welding skin is a red copper strip, the thickness of the red copper strip is 0.3mm, and the width of the red copper strip is 7 mm.

The filling rate of the flux-cored powder in the welding wire is 25-30 wt.%.

The flux-cored wire has the following functions and functions of the components:

the Cu element is used as a main alloy element of the flux-cored wire, the Cu element and the Ti element react to generate a plurality of Cu-Ti compounds, and a brittle phase is not formed between Cu and Fe, so that Cu is the most ideal element for preparing the titanium-steel gradient composite structure. In addition, the melting point of the Cu alloy is low, and low heat input can be selected in the additive manufacturing process;

cr and Ni elements are used as main components of the traditional Chinese medicine powder of the flux-cored wire, Cr-Ti intermetallic compounds can be formed between Cr and Ti, and the weldability between Cr and Fe is good; various intermetallic compounds of Ni-Ti can be formed between Ni and Ti, and the weldability between Ni and Fe is good; ni and Cr also have excellent weldability. Therefore, the addition of the 2 elements can comprehensively regulate and control the distribution and the content of the Cu-Ti intermetallic compound in the gradient layer, and avoid the appearance of a coarse structure.

The Nb element is used as the other main component of the traditional Chinese medicine powder of the flux-cored wire, the welding property between Nb and Ti is good, an infinite solid solution can be generated, and the plasticity and toughness are good. Therefore, the addition of Nb can strengthen the connection between the gradient layer and the titanium side.

The addition of Co element can improve the strength of the welding seam through dispersion strengthening and solid solution strengthening on one hand, and can also improve the high-temperature performance of the welding seam on the other hand;

the invention also provides a preparation method of the transition layer welding wire for preparing the titanium-steel gradient composite material CMT, which comprises the following specific steps:

step 1: respectively weighing 10-20% of Cr powder, 10-20% of Ni powder, 10-20% of Nb powder, 5-10% of Co powder and the balance of Cu powder according to mass percent, wherein the sum of the mass percentages of the components is 100%;

in the step 1, the purity of Cr powder is more than or equal to 99.9 percent, the purity of Ni powder is more than or equal to 99.9 percent, the purity of Nb powder is more than or equal to 99.9 percent, the purity of Co powder is more than or equal to 99.9 percent, the purity of Cu powder is more than or equal to 99.9 percent, and the granularity of 5 metal powders is 100-200 meshes.

Step 2: placing the Cr powder, the Ni powder, the Nb powder, the Co powder and the Cu powder weighed in the step 1 into a vacuum heating furnace for heating at the temperature of 150-200 ℃ for 1-2 h, and removing crystal water in the medicinal powder; placing the dried medicinal powder in a powder mixer for mixing for 30-40 min;

and step 3: a red copper strip is used as a welding skin, oil on the surface of the red copper strip is removed by adopting alcohol, the powder prepared in the step 2 is wrapped in the red copper strip by flux-cored wire drawing equipment, and the aperture of a first drawing grinding tool is 2.6 mm;

in the step 3, the thickness of the red copper strip is 0.3mm, and the width is 7 mm.

And 4, step 4: after the first process is finished, the aperture of a grinding tool is reduced in sequence for drawing, and the diameter of the finally obtained flux-cored wire is 1.2 mm; the filling rate of the flux-cored powder in the welding wire is 25-30 wt.%.

And 5: and after the flux-cored wire is drawn, the flux-cored wire is wound on a wire reel through a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for later use.

Example 1

Step 1: respectively weighing 20% of Cr powder, 20% of Ni powder, 20% of Nb powder, 10% of Co powder and the balance of Cu powder according to the mass percent, wherein the sum of the mass percent of the components is 100%.

In step 1, the purity of Cr powder is more than or equal to 99.9%, the purity of Ni powder is more than or equal to 99.9%, the purity of Nb powder is more than or equal to 99.9%, the purity of Co powder is more than or equal to 99.9%, the purity of Cu powder is more than or equal to 99.9%, and the granularity of 5 metal powders is 100 meshes.

Step 2: placing the Cr powder, the Ni powder, the Nb powder, the Co powder and the Cu powder which are weighed in the step 1 into a vacuum heating furnace for heating, wherein the heating temperature is 150 ℃, the heat preservation time is 1h, and removing crystal water in the medicinal powder; placing the dried medicinal powder in a powder mixer for mixing for 30 min;

and step 3: a red copper strip is used as a welding skin, oil on the surface of the red copper strip is removed by adopting alcohol, the powder prepared in the step 2 is wrapped in the red copper strip by flux-cored wire drawing equipment, and the aperture of a first drawing grinding tool is 2.6 mm;

in the step 3, the thickness of the red copper strip is 0.3mm, and the width is 7 mm.

And 4, step 4: after the first process is finished, the aperture of a grinding tool is reduced in sequence for drawing, and the diameter of the finally obtained flux-cored wire is 1.2 mm; the fill rate of the flux core powder in the wire was 25 wt.%.

And 5: and after the flux-cored wire is drawn, the flux-cored wire is wound on a wire reel through a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for later use.

Using the transition layer welding wire for preparing the titanium-steel gradient composite material CMT prepared in example 1, preparing a gradient layer by means of CMT equipment, wherein fig. 1 is a schematic view of a titanium-steel gradient composite structure, as shown in fig. 1, firstly performing surfacing welding on a steel substrate, and the welding current is as follows: 150-180A; and (3) after the gradient layer reaches 5mm, overlaying a titanium layer on the gradient layer by using an ERTi-1 welding wire, wherein the welding current is as follows: 100-.

Through tests, the mechanical properties of the welding joint are as follows: tensile strength 521MPa and elongation after fracture 12 percent.

Example 2

Step 1: respectively weighing 10% of Cr powder, 10% of Ni powder, 10% of Nb powder, 5% of Co powder and the balance of Cu powder according to the mass percentage, wherein the sum of the mass percentages of the components is 100%.

In step 1, the purity of Cr powder is more than or equal to 99.9%, the purity of Ni powder is more than or equal to 99.9%, the purity of Nb powder is more than or equal to 99.9%, the purity of Co powder is more than or equal to 99.9%, the purity of Cu powder is more than or equal to 99.9%, and the granularity of 5 metal powders is 200 meshes.

Step 2: placing the Cr powder, the Ni powder, the Nb powder, the Co powder and the Cu powder which are weighed in the step 1 into a vacuum heating furnace for heating, wherein the heating temperature is 150 ℃, the heat preservation time is 1h, and removing crystal water in the medicinal powder; placing the dried medicinal powder in a powder mixer for mixing for 30 min;

and step 3: a red copper strip is used as a welding skin, oil on the surface of the red copper strip is removed by adopting alcohol, the powder prepared in the step 2 is wrapped in the red copper strip by flux-cored wire drawing equipment, and the aperture of a first drawing grinding tool is 2.6 mm;

in the step 3, the thickness of the red copper strip is 0.3mm, and the width is 7 mm.

And 4, step 4: after the first process is finished, the aperture of a grinding tool is reduced in sequence for drawing, and the diameter of the finally obtained flux-cored wire is 1.2 mm; the filling rate of the flux core powder in the wire was 35 wt.%.

And 5: and after the flux-cored wire is drawn, the flux-cored wire is wound on a wire reel through a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for later use.

Using the transition layer welding wire for preparing the titanium-steel gradient composite material CMT prepared in example 2, firstly, overlaying is performed on a steel substrate, a gradient layer is prepared by means of CMT equipment, and the welding current is as follows: 150-180A; when the gradient layer reaches 5mm, overlaying an ERTi-1 welding wire on the gradient layer, wherein the welding current is as follows: 100-.

Through tests, the mechanical properties of the welding joint are as follows: tensile strength is 551MPa, and elongation after fracture is 15%.

The appearance of a surfacing structure of the flux-cored wire prepared in the embodiment 2 on a steel substrate is shown in fig. 2, and the structure mainly comprises a Cu-based solid solution and a Fe-based solid solution; the appearance of the overlaying structure of the flux-cored wire prepared in the embodiment 2 on a titanium substrate is shown in fig. 3, and the structure is mainly a Cu-Ti intermetallic compound; the flux-cored wire prepared in example 2 was used to prepare a titanium-steel gradient structure, and the structure of the gradient layer was mainly columnar Cu-Ti compounds, Cu-based solid solutions, and Fe-based solid solutions, as shown in fig. 4. The above observation shows that no cracks, pores and other common defects are found.

The CMT cold metal transition welding technology is adopted as a heat source, and is a brand-new MIG/MAG welding process. This technique links wire feed to welding process control. In the welding process, when a short-circuit signal of excessive molten drops is monitored in a circuit, the short-circuit signal is immediately fed back to a wire feeder, the wire feeder quickly responds, the welding wire is drawn back, the molten drops are separated from the end part of the welding wire in a mechanical force mode, and molten drop transition is assisted.

Example 3

Step 1: weighing 15% of Cr powder, 15% of Ni powder, 15% of Nb powder and 7% of Co powder according to the mass percent, and the balance of Cu powder, wherein the sum of the mass percent of the components is 100%.

In step 1, the purity of Cr powder is more than or equal to 99.9%, the purity of Ni powder is more than or equal to 99.9%, the purity of Nb powder is more than or equal to 99.9%, the purity of Co powder is more than or equal to 99.9%, the purity of Cu powder is more than or equal to 99.9%, and the granularity of 5 metal powders is 100 meshes.

Step 2: placing the Cr powder, the Ni powder, the Nb powder, the Co powder and the Cu powder which are weighed in the step 1 into a vacuum heating furnace for heating, wherein the heating temperature is 150 ℃, the heat preservation time is 1h, and removing crystal water in the medicinal powder; placing the dried medicinal powder in a powder mixer for mixing for 30 min;

and step 3: a red copper strip is used as a welding skin, oil on the surface of the red copper strip is removed by adopting alcohol, the powder prepared in the step 2 is wrapped in the red copper strip by flux-cored wire drawing equipment, and the aperture of a first drawing grinding tool is 2.6 mm;

in the step 3, the thickness of the red copper strip is 0.3mm, and the width is 7 mm.

And 4, step 4: after the first process is finished, the aperture of a grinding tool is reduced in sequence for drawing, and the diameter of the finally obtained flux-cored wire is 1.2 mm; the filling rate of the flux core powder in the wire was 30 wt.%.

And 5: and after the flux-cored wire is drawn, the flux-cored wire is wound on a wire reel through a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for later use.

Using the transition layer welding wire for preparing the titanium-steel gradient composite material CMT prepared in example 3, firstly, overlaying was performed on a steel substrate, and a gradient layer was prepared by means of CMT equipment, with welding currents: 150-180A; when the gradient layer reaches 5mm, overlaying an ERTi-1 welding wire on the gradient layer, wherein the welding current is as follows: 100-.

Through tests, the mechanical properties of the welding joint are as follows: the tensile strength is 505MPa, and the elongation after fracture is 8 percent.

Example 4

Step 1: respectively weighing 10% of Cr powder, 17% of Ni powder, 13% of Nb powder, 10% of Co powder and the balance of Cu powder according to the mass percent, wherein the sum of the mass percent of the components is 100%.

In step 1, the purity of Cr powder is more than or equal to 99.9%, the purity of Ni powder is more than or equal to 99.9%, the purity of Nb powder is more than or equal to 99.9%, the purity of Co powder is more than or equal to 99.9%, the purity of Cu powder is more than or equal to 99.9%, and the granularity of 5 metal powders is 100 meshes.

Step 2: placing the Cr powder, the Ni powder, the Nb powder, the Co powder and the Cu powder which are weighed in the step 1 into a vacuum heating furnace for heating, wherein the heating temperature is 200 ℃, the heat preservation time is 2 hours, and removing crystal water in the medicinal powder; placing the dried medicinal powder in a powder mixer for mixing for 30 min;

and step 3: a red copper strip is used as a welding skin, oil on the surface of the red copper strip is removed by adopting alcohol, the powder prepared in the step 2 is wrapped in the red copper strip by flux-cored wire drawing equipment, and the aperture of a first drawing grinding tool is 2.6 mm;

in the step 3, the thickness of the red copper strip is 0.3mm, and the width is 7 mm.

And 4, step 4: after the first process is finished, the aperture of a grinding tool is reduced in sequence for drawing, and the diameter of the finally obtained flux-cored wire is 1.2 mm; the filling rate of the flux core powder in the wire was 30 wt.%.

And 5: and after the flux-cored wire is drawn, the flux-cored wire is wound on a wire reel through a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for later use.

Using the transition layer welding wire for preparing the titanium-steel gradient composite material CMT prepared in example 4, firstly, overlaying was performed on a steel substrate, and a gradient layer was prepared by means of CMT equipment, with welding currents: 150-180A; when the gradient layer reaches 5mm, overlaying an ERTi-1 welding wire on the gradient layer, wherein the welding current is as follows: 100-.

Through tests, the mechanical properties of the welding joint are as follows: tensile strength is 528MPa, and elongation after fracture is 11%.

Example 5

Step 1: weighing 12% of Cr powder, 20% of Ni powder, 10% of Nb powder, 8% of Co powder and the balance of Cu powder according to the mass percent, wherein the sum of the mass percent of the components is 100%.

Step 2: placing the Cr powder, the Ni powder, the Nb powder, the Co powder and the Cu powder which are weighed in the step 1 into a vacuum heating furnace for heating, wherein the heating temperature is 150 ℃, the heat preservation time is 2 hours, and removing crystal water in the medicinal powder; placing the dried medicinal powder in a powder mixer for mixing for 30 min;

and step 3: removing grease on the surface of the red copper strip by using alcohol, wrapping the medicinal powder prepared in the step (2) in the red copper strip by using flux-cored wire drawing equipment, wherein the aperture of a first drawing grinding tool is 2.6 mm;

and 4, step 4: after the first process is finished, the aperture of a grinding tool is reduced in sequence for drawing, and the diameter of the finally obtained flux-cored wire is 1.2 mm;

and 5: and after the flux-cored wire is drawn, the flux-cored wire is wound on a wire reel through a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for later use.

Using the transition layer welding wire for preparing the titanium-steel gradient composite material CMT prepared in example 5, firstly, overlaying was performed on a steel substrate, and a gradient layer was prepared by means of CMT equipment, with welding currents: 150-180A; when the gradient layer reaches 5mm, overlaying an ERTi-1 welding wire on the gradient layer, wherein the welding current is as follows: 100-.

Through tests, the mechanical properties of the welding joint are as follows: tensile strength of 533MPa, and elongation after fracture of 11%.