Vanadium-based welding wire for welding titanium-steel dissimilar materials and preparation method thereof

Abstract

The application discloses a vanadium-based welding wire for welding titanium-steel dissimilar materials, which comprises a core and a welding sheath. The core is composed of the following components in percentage by mass: Cu powder 40-60%, Ag powder 10-20%, Mo powder 5-10%, Co powder 1-3%, CeO2 powder 0.5-1%, and the rest V powder. The sum of the above components is 100%. The welding wire solves the cracking problem of titanium-steel dissimilar materials during fusion welding. The application further discloses a preparation method of the vanadium-based welding wire for welding titanium-steel dissimilar materials.

Description

Technical Field

[0001] This invention belongs to the field of metal material welding technology, specifically relating to a vanadium-based welding wire for welding dissimilar materials such as titanium and steel. This invention also relates to a method for preparing the vanadium-based welding wire for welding dissimilar materials such as titanium and steel. Background Technology

[0002] Titanium and its alloys possess excellent corrosion resistance, but are expensive; steel, on the other hand, offers advantages such as low cost and high strength. Titanium-steel dissimilar material welded structures effectively combine the superior corrosion resistance of titanium with the high strength and low cost of steel, attracting significant attention in engineering practice. However, according to the Ti-Fe binary phase diagram, direct fusion welding of the two materials generates brittle intermetallic compounds, FeTi and Fe2Ti, leading to severe joint cracking.

[0003] An effective way to avoid cracking in titanium-steel dissimilar joints is to avoid the metallurgical reaction between Ti and Fe. However, avoiding the reaction between Ti and Fe under fusion welding conditions is very difficult. How to achieve direct fusion welding of titanium and steel has always been a key focus and challenge for researchers. Existing research has found that using one or more alloying elements to indirectly achieve titanium-steel bonding is a feasible approach. Summary of the Invention

[0004] The purpose of this invention is to provide vanadium-based welding wire for welding dissimilar materials such as titanium and steel, which solves the cracking problem during the fusion welding of dissimilar materials such as titanium and steel.

[0005] Another object of the present invention is to provide a method for preparing vanadium-based welding wire for welding dissimilar materials such as titanium and steel.

[0006] The first technical solution adopted in this invention is a vanadium-based welding wire for welding dissimilar materials such as titanium and steel, comprising a flux core and a welding sheath, wherein the flux powder is composed of the following components by mass percentage: 40-60% Cu powder, 10-20% Ag powder, 5-10% Mo powder, 1-3% Co powder, 0.5-1% CeO2 powder, and the remainder being V powder, and the sum of the mass percentages of the above components is 100%.

[0007] The invention is further characterized in that,

[0008] The purity of each core powder is ≥99.9%, and the particle size of each core powder is 100-200 mesh.

[0009] The soldering material is made of pure vanadium strip, with a thickness of 0.3 mm and a width of 7 mm.

[0010] The filling amount of flux-cored welding wire is controlled between 30wt% and 32wt%.

[0011] The second technical solution adopted in this invention is a method for preparing the above-mentioned vanadium-based welding wire for welding dissimilar titanium and steel materials, the specific steps of which are as follows:

[0012] Step 1: Weigh the following powders according to their mass percentages: Cu powder 40-60%, Ag powder 10-20%, Mo powder 5-10%, Co powder 1-3%, CeO2 powder 0.5-1%, and the remainder is V powder. The sum of the mass percentages of the above components is 100%.

[0013] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at a temperature of 200℃~250℃ for 1h~3h to remove the water of crystallization from the powder; place the dried powder into a powder mixer for thorough mixing for 30min~40min.

[0014] Step 3: Use alcohol to remove the grease from the surface of the pure vanadium strip, and use a flux-cored wire drawing device to wrap the flux powder prepared in step 2 inside the pure vanadium strip. The diameter of the first drawing die is 2.6mm.

[0015] Step 4: After the first drawing process is completed, the die diameter is changed to 2.5mm, 2.3mm, 2.1mm, 1.9mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm, and 1.2mm respectively for drawing. The final diameter of the flux-cored wire is 1.2mm. Step 5: After the flux-cored wire is drawn, it is wound onto the wire spool by a wire winding machine and finally sealed in a flux-cored wire vacuum packaging bag for later use.

[0016] The invention is further characterized in that,

[0017] In step 1, the purity of each core powder is ≥99.9%, and the particle size of each core powder is 100-200 mesh.

[0018] In step 3, the pure vanadium strip is used as the welding skin, with a thickness of 0.3 mm and a width of 7 mm; the filling amount of the flux-cored welding wire is controlled between 30 wt% and 32 wt%.

[0019] The beneficial effects of this invention are:

[0020] (1) The flux-cored wire of the present invention has a relatively small diameter. The flux-cored wire with a wire diameter of 1.2 mm is widely applicable. It can be used for both TIG welding and MIG welding.

[0021] (2) The flux-cored welding wire of the present invention uses multiple alloying elements such as V, Cu, Ag, Mo, and Co to achieve the welding connection of dissimilar joints of titanium and steel, thus solving the cracking problem that occurs in the welding of titanium and steel: V and Cu alloys act as a bridge connecting Ti and Fe elements; Ag element lowers the melting point of the weld and improves the fluidity and toughness of the weld; Mo and Co elements strengthen the weld metal.

[0022] (3) The flux-cored welding wire of the present invention incorporates CeO2 to fully purify the grain boundaries and reduce the tendency of joint cracking.

[0023] (4) The flux-cored welding wire of the present invention has fewer alloy elements, the preparation process is simple, and it is easy to carry out large-scale mass production. Attached Figure Description

[0024] Figure 1 The microstructure of the steel side of the flux-cored welding wire prepared in Example 2 during the welding of dissimilar titanium and steel materials;

[0025] Figure 2 The microstructure of the weld seam when the flux-cored welding wire prepared in Example 2 is used for welding dissimilar materials such as titanium and steel;

[0026] Figure 3 The flux-cored welding wire prepared in Example 2 was used for titanium-steel dissimilar material welding, and the tensile fracture morphology of the joint after welding was obtained. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0028] This invention provides a vanadium-based welding wire for welding dissimilar materials such as titanium and steel, comprising a flux core and a welding sheath, wherein the flux powder is composed of the following components by mass percentage: 40-60% Cu powder, 10-20% Ag powder, 5-10% Mo powder, 1-3% Co powder, 0.5-1% CeO2 powder, and the remainder being V powder, the sum of the mass percentages of the above components being 100%.

[0029] The purity of each core powder is ≥99.9%, and the particle size of each core powder is 100-200 mesh.

[0030] The soldering material is made of pure vanadium strip, with a thickness of 0.3 mm and a width of 7 mm.

[0031] The filling amount of flux-cored welding wire is controlled between 30wt% and 32wt%.

[0032] The roles and functions of each component in this flux-cored welding wire are as follows:

[0033] (1) V is the main alloying element of welding wire. According to the V-Ti binary phase diagram, V and Ti can be infinitely dissolved at high temperature, resulting in excellent weldability; according to the V-Fe binary phase diagram, V and Fe have a certain degree of solid solubility within a certain range, which allows for welding connection.

[0034] (2) Cu is the main alloying element in welding wire powder. According to the Cu-V binary phase diagram, V and Cu do not form intermetallic compounds, so welding is possible; according to the Cu-Ti binary phase diagram, although Cu and Ti will form various intermetallic compounds, their brittleness is much lower than that of the Fi-Ti brittle phase; according to the Cu-Fe binary phase diagram, the two do not form brittle intermetallic compounds, so welding is possible.

[0035] (3) Ag is the main alloying element in welding wire powder. Ag has a low melting point, and Ag, Cu and Ti will form a eutectic structure with good plasticity and toughness, thus avoiding the formation of a large-scale Cu-Ti phase.

[0036] (4) Mo and Co are additive elements in welding wire powder. Mo and Co are dissolved in vanadium-based welds and can strengthen the strength of vanadium-based welds. In addition, Mo and Co have good weldability with steel, and these two alloying elements can improve the bonding strength between the weld and the steel.

[0037] (7) The addition of CeO2 oxide can purify the grain boundaries of the weld and improve the grain boundary bonding force, thereby improving the plasticity and toughness of vanadium-based welds.

[0038] The present invention also provides a method for preparing the above-mentioned vanadium-based welding wire for welding dissimilar titanium and steel materials, the specific steps of which are as follows:

[0039] Step 1: Weigh the following powders according to their mass percentages: Cu powder 40-60%, Ag powder 10-20%, Mo powder 5-10%, Co powder 1-3%, CeO2 powder 0.5-1%, and the remainder is V powder. The sum of the mass percentages of the above components is 100%.

[0040] In step 1, the purity of each core powder is ≥99.9%, and the particle size of each core powder is 100-200 mesh.

[0041] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at a temperature of 200℃~250℃ for 1h~3h to remove the water of crystallization from the powder; place the dried powder into a powder mixer for thorough mixing for 30min~40min.

[0042] Step 3: Remove the grease from the surface of the pure vanadium strip with alcohol, and wrap the flux powder prepared in Step 2 inside the pure vanadium strip using a flux-cored wire drawing device. The diameter of the first drawing die is 2.6 mm. In Step 3, the pure vanadium strip is the welding skin with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the flux-cored wire is controlled between 30 wt% and 32 wt%.

[0043] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.5mm, 2.3mm, 2.1mm, 1.9mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm and 1.2mm respectively for drawing. The final diameter of the flux-cored wire is 1.2mm.

[0044] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use.

[0045] Example 1

[0046] Step 1: Weigh out 40% Cu powder, 10% Ag powder, 5% Mo powder, 1% Co powder, 0.5% CeO2 powder, and the remainder is V powder, according to the following mass percentages. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each core powder is ≥99.9%, and the particle size of each core powder is 100 mesh.

[0047] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at 200℃ for 1 hour to remove the water of crystallization from the powder; place the dried powder into a powder mixer for thorough mixing for 30 minutes.

[0048] Step 3: Remove the grease from the surface of the pure vanadium strip with alcohol, and wrap the flux powder prepared in Step 2 inside the pure vanadium strip using a flux-cored wire drawing device. The diameter of the first drawing die is 2.6 mm. In Step 3, the pure vanadium strip is the welding skin, with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the flux-cored wire is controlled at 32 wt%.

[0049] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.5mm, 2.3mm, 2.1mm, 1.9mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm and 1.2mm respectively for drawing. The final diameter of the flux-cored wire is 1.2mm.

[0050] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use.

[0051] The welding wire prepared in Example 1 was used for titanium-steel dissimilar material welding, and the results are as follows:

[0052] (1) The arc is stable, spatter is less, the weld formation is beautiful, and the molten pool has good fluidity during the welding of dissimilar materials such as titanium and steel.

[0053] (2) The tensile strength of the titanium-steel dissimilar material joint is 451 MPa, and the elongation after fracture is 12%.

[0054] (3) The average value of the micro Vickers hardness at the center of the weld of the titanium-steel dissimilar material joint is 320HV0.2.

[0055] Example 2

[0056] Step 1: Weigh out the following components by mass percentage: 60% Cu powder, 20% Ag powder, 10% Mo powder, 3% Co powder, 1% CeO2 powder, and the remainder is V powder. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each core powder is ≥99.9%, and the particle size of each core powder is 200 mesh.

[0057] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at 250℃ for 3 hours to remove the water of crystallization from the powder; place the dried powder into a powder mixer for thorough mixing for 40 minutes.

[0058] Step 3: Remove the grease from the surface of the pure vanadium strip with alcohol, and wrap the flux powder prepared in Step 2 inside the pure vanadium strip using a flux-cored wire drawing device. The diameter of the first drawing die is 2.6 mm. In Step 3, the pure vanadium strip is the welding skin, with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the flux-cored wire is controlled at 30 wt%.

[0059] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.5mm, 2.3mm, 2.1mm, 1.9mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm and 1.2mm respectively for drawing. The final diameter of the flux-cored wire is 1.2mm.

[0060] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use.

[0061] The welding wire prepared in Example 2 was used for titanium-steel dissimilar material welding, and the results are as follows:

[0062] (1) The arc is stable, spatter is less, the weld formation is beautiful, and the molten pool has good fluidity during the welding of dissimilar materials such as titanium and steel.

[0063] (2) The tensile strength of the titanium-steel dissimilar material joint is 460 MPa and the elongation after fracture is 11%.

[0064] (3) The average micro Vickers hardness at the center of the weld of the titanium-steel dissimilar material joint is 342HV0.2.

[0065] Figure 1 The flux-cored welding wire prepared in Example 2 was used for welding titanium-steel dissimilar materials, with the steel side undergoing microstructure analysis. As can be seen from the figure, the weld seam and the steel base material exhibit good bonding, with no cracks or porosity defects observed. Using the vanadium-based welding wire for welding titanium-steel dissimilar materials prepared in Example 2 solved the cracking problem during fusion welding of titanium-steel dissimilar materials.

[0066] Figure 2 The flux-cored welding wire prepared in Example 2 was used for welding titanium and steel dissimilar materials. The microstructure of the weld is shown in the figure. As can be seen from the figure, the weld is mainly composed of vanadium-based solid solution and copper-based solid solution, and no cracks or porosity defects are observed.

[0067] Figure 3 The flux-cored welding wire prepared in Example 2 was used for titanium-steel dissimilar material welding. The tensile fracture morphology of the welded joint is shown in the figure. As can be seen from the figure, the fracture is mainly characterized by quasi-cleavage fracture, and a bremsstrahlung morphology can be observed.

[0068] Example 3

[0069] Step 1: Weigh out 50% Cu powder, 15% Ag powder, 7% Mo powder, 2% Co powder, 0.7% CeO2 powder, and the remainder is V powder, according to the following mass percentages. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each core powder is ≥99.9%, and the particle size of each core powder is 100 mesh.

[0070] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at 220℃ for 2 hours to remove the water of crystallization from the powder; place the dried powder into a powder mixer for thorough mixing for 35 minutes.

[0071] Step 3: Remove the grease from the surface of the pure vanadium strip with alcohol, and wrap the flux powder prepared in Step 2 inside the pure vanadium strip using a flux-cored wire drawing device. The diameter of the first drawing die is 2.6 mm. In Step 3, the pure vanadium strip is the welding skin, with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the flux-cored wire is controlled at 31 wt%.

[0072] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.5mm, 2.3mm, 2.1mm, 1.9mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm and 1.2mm respectively for drawing. The final diameter of the flux-cored wire is 1.2mm.

[0073] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use.

[0074] The welding wire prepared in Example 3 was used for titanium-steel dissimilar material welding, and the results are as follows:

[0075] (1) The arc is stable, spatter is less, the weld formation is beautiful, and the molten pool has good fluidity during the welding of dissimilar materials such as titanium and steel.

[0076] (2) The tensile strength of the titanium-steel dissimilar material joint is 447 MPa, and the elongation after fracture is 12.5%.

[0077] (3) The average micro Vickers hardness at the center of the weld of the titanium-steel dissimilar material joint is 327HV0.2.

[0078] Example 4

[0079] Step 1: Weigh out the following components by mass percentage: 45% Cu powder, 12% Ag powder, 6% Mo powder, 1.3% Co powder, 0.6% CeO2 powder, and the remainder is V powder. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each core powder is ≥99.9%, and the particle size of each core powder is 200 mesh.

[0080] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at 210℃ for 1.3 hours to remove the water of crystallization from the powder; place the dried powder into a powder mixer for thorough mixing for 34 minutes.

[0081] Step 3: Remove the grease from the surface of the pure vanadium strip with alcohol, and wrap the flux powder prepared in Step 2 inside the pure vanadium strip using a flux-cored wire drawing device. The diameter of the first drawing die is 2.6 mm. In Step 3, the pure vanadium strip is the welding skin, with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the flux-cored wire is controlled at 32 wt%.

[0082] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.5mm, 2.3mm, 2.1mm, 1.9mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm and 1.2mm respectively for drawing. The final diameter of the flux-cored wire is 1.2mm.

[0083] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use.

[0084] The welding wire prepared in Example 4 was used for titanium-steel dissimilar material welding, and the results are as follows:

[0085] (1) The arc is stable, spatter is less, the weld formation is beautiful, and the molten pool has good fluidity during the welding of dissimilar materials such as titanium and steel.

[0086] (2) The tensile strength of the titanium-steel dissimilar material joint is 459 MPa, and the elongation after fracture is 13.7%.

[0087] (3) The average micro Vickers hardness at the center of the weld of the titanium-steel dissimilar material joint is 318HV0.2.

[0088] Example 5

[0089] Step 1: Weigh out the following components by mass percentage: 59% Cu powder, 19% Ag powder, 9% Mo powder, 2.8% Co powder, 0.65% CeO2 powder, with the remainder being V powder. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each core powder is ≥99.9%, and the particle size of each core powder is 100 mesh.

[0090] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at 245℃ for 2.7 hours to remove the water of crystallization from the powder; place the dried powder into a powder mixer for thorough mixing for 37 minutes.

[0091] Step 3: Remove the grease from the surface of the pure vanadium strip with alcohol, and wrap the flux powder prepared in Step 2 inside the pure vanadium strip using a flux-cored wire drawing device. The diameter of the first drawing die is 2.6 mm. In Step 3, the pure vanadium strip is the welding skin, with a thickness of 0.3 mm and a width of 7 mm. The filling amount of the flux-cored wire is controlled at 30 wt%.

[0092] Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.5mm, 2.3mm, 2.1mm, 1.9mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm and 1.2mm respectively for drawing. The final diameter of the flux-cored wire is 1.2mm.

[0093] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use.

[0094] The welding wire prepared in Example 5 was used for titanium-steel dissimilar material welding, and the results are as follows:

[0095] (1) The arc is stable, spatter is less, the weld formation is beautiful, and the molten pool has good fluidity during the welding of dissimilar materials such as titanium and steel.

[0096] (2) The tensile strength of the titanium-steel dissimilar material joint is 458 MPa, and the elongation after fracture is 15%.

[0097] (3) The average micro Vickers hardness at the center of the weld of the titanium-steel dissimilar material joint is 334HV0.2.

Claims

1. A vanadium-based welding wire for welding dissimilar materials such as titanium and steel, characterized in that, It includes a flux core and a solder coating. The flux core powder is composed of the following components by mass percentage: 40-60% Cu powder, 10-20% Ag powder, 5-10% Mo powder, 1-3% Co powder, 0.5-1% CeO2 powder, and the remainder is V powder. The sum of the mass percentages of the above components is 100%. The solder coating is made of pure vanadium strip. The filling amount of the flux core wire is controlled at 30wt%-32wt%.

2. The vanadium-based welding wire for welding dissimilar materials of titanium and steel according to claim 1, characterized in that, The purity of each core powder is ≥99.9%, and the particle size of each core powder is 100~200 mesh.

3. The vanadium-based welding wire for welding dissimilar materials of titanium and steel according to claim 1, characterized in that, The thickness of the solder coating is 0.3mm and the width is 7mm.

4. A method for preparing vanadium-based welding wire for welding dissimilar materials such as titanium and steel, characterized in that, The specific steps are as follows: Step 1: Weigh the following core powders according to their mass percentages: Cu powder 40-60%, Ag powder 10-20%, Mo powder 5-10%, Co powder 1-3%, CeO2 powder 0.5-1%, and the remainder is V powder. The sum of the mass percentages of the above components is 100%. Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at a temperature of 200℃~250℃ for 1h~3h; place the dried core powder into a powder mixer for thorough mixing for 30min~40min. Step 3: The flux-cored powder prepared in Step 2 is wrapped in pure vanadium strip using a flux-cored wire drawing machine. The diameter of the first drawing die is 2.6 mm. The filling amount of the flux-cored wire is controlled between 30 wt% and 32 wt%. Step 4: After the first drawing process is completed, the die hole diameter is changed to 2.5mm, 2.3mm, 2.1mm, 1.9mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm and 1.2mm respectively for drawing. The final diameter of the flux-cored wire is 1.2mm. Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use.

5. The method for preparing vanadium-based welding wire for titanium-steel dissimilar material welding according to claim 4, characterized in that, In step 1, the purity of each core powder is ≥99.9%, and the particle size of each core powder is 100~200 mesh.

6. The method for preparing vanadium-based welding wire for titanium-steel dissimilar material welding according to claim 4, characterized in that, In step 3, the pure vanadium strip is used as a solder pad, with a thickness of 0.3 mm and a width of 7 mm.

Images