Welding wire for welding heat-resistant steel and stainless steel dissimilar materials and preparation method thereof

Abstract

The application discloses a welding wire for welding heat-resistant steel and stainless steel dissimilar materials, which comprises a core and a welding sheath, wherein the core is composed of the following components in percentage by mass: Cr powder 30-40%, Nb powder 5-10%, V powder 5-6%, Mn powder 2-4%, Si powder 2-4%, Ti powder 1-3%, Co powder 1-3%, CeO2 powder 0.5-1%, Y2O3 powder 0.5-1%, and the rest is Ni powder, and the sum of the percentage by mass of the above components is 100%. The welding wire solves the problem of unstable performance when welding heat-resistant steel and stainless steel dissimilar materials. The application further discloses a preparation method of the welding wire for welding heat-resistant steel and stainless steel dissimilar materials.

Description

Technical Field

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

[0002] From an economic perspective, components operating at different temperatures in power plants utilize steels with varying chemical compositions and microstructures, inevitably leading to welding challenges between dissimilar steels during construction. Heat-resistant steel P91 and stainless steel TP347 are commonly used in power plant components. When austenitic stainless steel welds are within the sensitization temperature range (450–850℃) during welding and subsequent reheating, chromium-depleted grain boundaries are easily formed, resulting in intergranular corrosion. Problems in welding dissimilar martensitic and austenitic steels mainly include the formation of a brittle martensitic layer in the transition zone, decarburized and carburized layers in the diffusion zone, and thermal stress caused by differences in thermal expansion coefficients. Summary of the Invention

[0003] The purpose of this invention is to provide a welding wire for welding dissimilar materials such as heat-resistant steel and stainless steel, which solves the problem of unstable performance when welding these materials.

[0004] Another object of the present invention is to provide a method for preparing welding wire for welding dissimilar materials such as heat-resistant steel and stainless steel.

[0005] The first technical solution adopted in this invention is a welding wire for welding dissimilar materials of heat-resistant steel and stainless steel, comprising a flux core and a welding sheath, wherein the flux powder is composed of the following components by mass percentage: Cr powder 30-40%, Nb powder 5-10%, V powder 5-6%, Mn powder 2-4%, Si powder 2-4%, Ti powder 1-3%, Co powder 1-3%, CeO2 powder 0.5-1%, Y2O3 powder 0.5-1%, and the remainder is Ni powder, the sum of the mass percentages of the above components being 100%.

[0006] The invention is further characterized in that,

[0007] The purity of each powder is ≥99.9%, and the particle size of each powder is 100-200 mesh.

[0008] The solder pads are made of Inconel 625 tape, 0.3mm thick and 7mm wide.

[0009] The filling amount of flux-cored welding wire is controlled between 25wt% and 30wt%.

[0010] The second technical solution adopted in this invention is a method for preparing welding wire for welding dissimilar materials such as heat-resistant steel and stainless steel, the specific steps of which are as follows:

[0011] Step 1: Weigh out the following components by mass percentage: 30-40% Cr powder, 5-10% Nb powder, 5-6% V powder, 2-4% Mn powder, 2-4% Si powder, 1-3% Ti powder, 1-3% Co powder, 0.5-1% CeO2 powder, 0.5-1% Y2O3 powder, with the remainder being Ni powder. The sum of the mass percentages of the above components should be 100%.

[0012] 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.

[0013] Step 3: Use alcohol to remove the grease from the surface of the Inconel 625 strip, and use a flux-cored wire drawing device to wrap the flux powder prepared in step 2 inside the Inconel 625 strip. The diameter of the first drawing die is 2.6mm.

[0014] 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.

[0015] 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.

[0016] The invention is further characterized in that,

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

[0018] In step 3, the Inconel 625 strip is used as the solder skin, with a thickness of 0.3 mm and a width of 7 mm; the filler content of the flux-cored wire is controlled between 25 wt% and 30 wt%.

[0019] The beneficial effects of this invention are:

[0020] (1) The flux-cored welding wire of the present invention has a relatively small diameter. The flux-cored welding 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 is drawn from Inconel 625 welding strip, with low C content, high alloy element content, low tendency of joint brittleness, and more uniform composition of cladding metal.

[0022] (3) The flux-cored welding wire of the present invention is reinforced with multiple alloys such as Cr, Nb, and V, which can effectively improve the strength and toughness of the weld.

[0023] (4) The flux-cored welding wire of the present invention uses CeO2 and Y2O3 composite addition to fully purify the grain boundaries and reduce the tendency of joint cracking.

[0024] (5) 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.

[0025] (6) The flux-cored welding wire of the present invention is used as the filler material for welding T91 martensitic heat-resistant steel and TP347H austenitic stainless steel, thereby ensuring the stability of the welded joint of dissimilar materials T91 and TP347H in power plants. Attached Figure Description

[0026] Figure 1 The microstructure at the interface between T91 and the weld seam of the flux-cored wire prepared in Example 2 during the welding of dissimilar materials such as heat-resistant steel and stainless steel;

[0027] Figure 2 The microstructure of TP347H and the weld seam during the welding of heat-resistant steel and stainless steel dissimilar materials, prepared by Example 2.

[0028] Figure 3 The microstructure morphology of the weld seam when the flux-cored welding wire prepared in Example 2 is used for welding dissimilar materials of heat-resistant steel and stainless steel.

[0029] Figure 4 The tensile fracture morphology at the weld seam of the flux-cored welding wire prepared in Example 2 during the welding of dissimilar materials such as heat-resistant steel and stainless steel. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0031] This invention provides a welding wire for welding dissimilar materials such as heat-resistant steel and stainless steel, comprising a flux core and a welding sheath, wherein the flux powder is composed of the following components by mass percentage: 30-40% Cr powder, 5-10% Nb powder, 5-6% V powder, 2-4% Mn powder, 2-4% Si powder, 1-3% Ti powder, 1-3% Co powder, 0.5-1% CeO2 powder, 0.5-1% Y2O3 powder, and the remainder is Ni powder, the sum of the mass percentages of the above components being 100%.

[0032] The purity of each powder is ≥99.9%, and the particle size of each powder is 100-200 mesh.

[0033] The solder pads are made of Inconel 625 tape, 0.3mm thick and 7mm wide.

[0034] The filling amount of flux-cored welding wire is controlled between 25wt% and 30wt%.

[0035] The roles and functions of each component in this flux-cored welding wire are as follows:

[0036] (1) Ni is the main alloying element in flux-cored welding wire. According to the Ni-Fe binary phase diagram, the solid solubility between the two is high. Therefore, using Ni as the main alloying element in welding wire can ensure good metallurgical bonding between the weld and T91 martensitic heat-resistant steel and TP347H austenitic stainless steel. Ni can also effectively reduce the diffusion rate of carbon and the stability of carbides, and slow down carbon migration from the low-alloy heat-resistant steel side to the high-alloy steel side.

[0037] (2) Cr is the main alloying element of the flux-cored welding wire powder. According to the Fe-Cr binary phase diagram, Cr and Fe have high solid solubility and good weldability. According to the Cr-Ni binary phase diagram, both can be infinitely dissolved in the Ni matrix, and Cr dissolves in the Ni matrix, which can effectively improve the strength of the nickel-based weld. In addition, Cr can effectively improve the high-temperature resistance of the weld by generating Cr2O3 at high temperatures. The Cr content of the T91 base metal itself is about 8-10%. In this application, increasing the Cr content in the weld can effectively improve the Cr depletion on the T91 side.

[0038] (3) V, as the main alloying element of flux-cored welding wire powder, is a strong carbide-forming element. After being added, it can form fine and stable alloy carbides with carbon, which has a strong dispersion strengthening effect. According to the V-Fe binary phase diagram, there is a possibility of forming a brittle phase between V and Fe. Therefore, it is necessary to strictly control the V content in the welding wire to ensure that it is completely dissolved in the Ni matrix.

[0039] (4) Mn and Si, as deoxidizing elements, can be added to the welding wire to effectively reduce the tendency of the weld metal to produce porosity. In addition, Mn itself can be dissolved in Ni-based welds to improve the strength of the weld.

[0040] (5) As another additive element in flux-cored wire powder, Ti can react with Ni to form Ni3(Ti), which effectively improves the strength of nickel-based welds.

[0041] (6) As another additive element in flux-cored welding wire powder, Co can be dissolved in Ni-based welds to improve weld strength. In addition, Co can effectively improve the high-temperature resistance of welds.

[0042] (7) The combined addition of CeO2 and Y2O3 has the effect of purifying the grain boundaries of the weld, improving the grain boundary bonding force, and inhibiting carbon migration of the base material.

[0043] The present invention also provides a method for preparing the above-mentioned welding wire for welding dissimilar materials such as heat-resistant steel and stainless steel, the specific steps of which are as follows:

[0044] Step 1: Weigh out the following components by mass percentage: 30-40% Cr powder, 5-10% Nb powder, 5-6% V powder, 2-4% Mn powder, 2-4% Si powder, 1-3% Ti powder, 1-3% Co powder, 0.5-1% CeO2 powder, 0.5-1% Y2O3 powder, with the remainder being Ni powder. The sum of the mass percentages of the above components should be 100%. In Step 1, the purity of each powder should be ≥99.9%, and the particle size of each powder should be 100-200 mesh.

[0045] 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.

[0046] Step 3: Remove the grease from the surface of the Inconel 625 strip using alcohol. Then, wrap the flux powder prepared in Step 2 inside the Inconel 625 strip using a flux-cored wire drawing machine. The diameter of the first drawing die is 2.6 mm. In Step 3, the Inconel 625 strip is the solder 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 25 wt% and 30 wt%.

[0047] 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.

[0048] 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.

[0049] Example 1

[0050] Step 1: Weigh out the following components by mass percentage: 30% Cr powder, 5% Nb powder, 5% V powder, 2% Mn powder, 2% Si powder, 1% Ti powder, 1% Co powder, 0.5% CeO2 powder, 0.5% Y2O3 powder, and the remainder Ni powder. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each powder is ≥99.9%, and the particle size of each powder is 200 mesh.

[0051] 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.

[0052] Step 3: Remove the grease from the surface of the Inconel 625 strip using alcohol. Then, wrap the flux powder prepared in Step 2 inside the Inconel 625 strip using a flux-cored wire drawing machine. The first drawing die has a bore diameter of 2.6 mm. In Step 3, the Inconel 625 strip is the welding skin, with a thickness of 0.3 mm and a width of 7 mm. The flux-cored wire filling amount is controlled at 30 wt%.

[0053] 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.

[0054] 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.

[0055] The welding wire prepared in Example 1 was used for welding dissimilar materials of heat-resistant steel and stainless steel. The results are as follows:

[0056] (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 heat-resistant steel and stainless steel.

[0057] (2) The tensile strength of the heat-resistant steel-stainless steel dissimilar material joint is 681 MPa, and the elongation after fracture is 18%.

[0058] (3) The room temperature impact toughness of the heat-resistant steel-stainless steel dissimilar material joint is 100J.

[0059] Example 2

[0060] Step 1: Weigh out the following components by mass percentage: 40% Cr powder, 10% Nb powder, 6% V powder, 4% Mn powder, 4% Si powder, 3% Ti powder, 3% Co powder, 1% CeO2 powder, 1% Y2O3 powder, and the remainder is Ni powder. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each powder is ≥99.9%, and the particle size of each powder is 100 mesh.

[0061] 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.

[0062] Step 3: Remove the grease from the surface of the Inconel 625 strip with alcohol. Encapsulate the flux powder prepared in Step 2 into the Inconel 625 strip using a flux-cored wire drawing machine. The first drawing die has a bore diameter of 2.6 mm. In Step 3, the Inconel 625 strip is the solder skin, with a thickness of 0.3 mm and a width of 7 mm. The flux-cored wire filling amount is controlled at 25 wt%.

[0063] 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.

[0064] 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.

[0065] The welding wire prepared in Example 2 was used for welding dissimilar materials of heat-resistant steel and stainless steel. The results are as follows:

[0066] (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 heat-resistant steel and stainless steel.

[0067] (2) The tensile strength of the heat-resistant steel-stainless steel dissimilar material joint is 683 MPa, and the elongation after fracture is 19%.

[0068] (3) The room temperature impact toughness of the heat-resistant steel-stainless steel dissimilar material joint is 110J.

[0069] Figure 1 The image shows the microstructure at the interface between T91 and the weld seam when the flux-cored wire prepared in Example 2 is used for welding dissimilar materials of heat-resistant steel and stainless steel. As can be seen from the image, the T91 side is mainly composed of martensite with coarse grains. The interface between the weld metal and T91 is well bonded, and no defects such as cracks or pores were found.

[0070] Figure 2 The image shows the microstructure of TP347H and the weld seam during the welding of dissimilar materials, heat-resistant steel and stainless steel, using the flux-cored welding wire prepared in Example 2. As can be seen from the image, the TP347H base material is a single-phase austenitic structure with an equiaxed crystal morphology. The TP347H base material and the weld seam are well bonded, and no cracks or porosity defects were found.

[0071] Figure 3 The image shows the microstructure of the weld seam when the flux-cored welding wire prepared in Example 2 is used for welding dissimilar materials of heat-resistant steel and stainless steel. As can be seen from the image, the weld seam is dominated by columnar numerical crystals, with a microstructure of γ-Ni, accompanied by Ni3Ti strengthening phases. No defects such as porosity or cracks were found in the weld seam.

[0072] Figure 4 The image shows the tensile fracture morphology at the weld seam of the flux-cored welding wire prepared in Example 2 during the welding of dissimilar materials, heat-resistant steel and stainless steel. As can be seen from the image, the fracture surface is predominantly characterized by bulge morphology, indicating good toughness.

[0073] The nickel-based alloy welding wire prepared in Example 2 was used as filler material for welding T91 martensitic heat-resistant steel and TP347H austenitic stainless steel, thereby ensuring the stability of the welded joint of dissimilar materials T91 and TP347H in the power plant.

[0074] Example 3

[0075] Step 1: Weigh out the following components by mass percentage: 35% Cr powder, 7% Nb powder, 5.5% V powder, 3% Mn powder, 3% Si powder, 2% Ti powder, 2% Co powder, 0.7% CeO2 powder, 0.7% Y2O3 powder, and the remainder Ni powder. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each powder is ≥99.9%, and the particle size of each powder is 100 mesh.

[0076] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at 230℃ 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.

[0077] Step 3: Remove the grease from the surface of the Inconel 625 strip using alcohol. Then, wrap the flux powder prepared in Step 2 inside the Inconel 625 strip using a flux-cored wire drawing machine. The diameter of the first drawing die is 2.6 mm. In Step 3, the Inconel 625 strip is the solder 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 28 wt%.

[0078] 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.

[0079] 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.

[0080] The welding wire prepared in Example 3 was used for welding dissimilar materials of heat-resistant steel and stainless steel. The results are as follows:

[0081] (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 heat-resistant steel and stainless steel.

[0082] (2) The tensile strength of the heat-resistant steel-stainless steel dissimilar material joint is 695MPa and the elongation after fracture is 17%.

[0083] (3) The room temperature impact toughness of the heat-resistant steel-stainless steel dissimilar material joint is 95J.

[0084] Example 4

[0085] Step 1: Weigh out the following components by mass percentage: 34% Cr powder, 6% Nb powder, 5.6% V powder, 2.4% Mn powder, 2.4% Si powder, 1.3% Ti powder, 1.3% Co powder, 0.6% CeO2 powder, 0.6% Y2O3 powder, and the remainder Ni powder. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each powder is ≥99.9%, and the particle size of each powder is 200 mesh.

[0086] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at 240℃ 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.

[0087] Step 3: Remove the grease from the surface of the Inconel 625 strip with alcohol. Then, wrap the flux powder prepared in Step 2 inside the Inconel 625 strip using a flux-cored wire drawing machine. The first drawing die has a bore diameter of 2.6 mm. In Step 3, the Inconel 625 strip is the solder skin, with a thickness of 0.3 mm and a width of 7 mm. The flux-cored wire filling amount is controlled at 26 wt%.

[0088] 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.

[0089] 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.

[0090] The welding wire prepared in Example 4 was used for welding dissimilar materials of heat-resistant steel and stainless steel. The results are as follows:

[0091] (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 heat-resistant steel and stainless steel.

[0092] (2) The tensile strength of the heat-resistant steel-stainless steel dissimilar material joint is 665MPa and the elongation after fracture is 22%.

[0093] (3) The room temperature impact toughness of the heat-resistant steel-stainless steel dissimilar material joint is 115J.

[0094] Example 5

[0095] Step 1: Weigh out the following components by mass percentage: 31% Cr powder, 9% Nb powder, 5.8% V powder, 3.5% Mn powder, 2.8% Si powder, 2.6% Ti powder, 2.7% Co powder, 0.65% CeO2 powder, 0.75% Y2O3 powder, and the remainder Ni powder. The sum of the mass percentages of the above components is 100%. In Step 1, the purity of each powder is ≥99.9%, and the particle size of each powder is 200 mesh.

[0096] Step 2: Place the core powder weighed in Step 1 into a vacuum heating furnace and heat it at 210℃ for 1.7 hours to remove the water of crystallization from the powder; place the dried powder into a powder mixer for thorough mixing for 32 minutes.

[0097] Step 3: Remove the grease from the surface of the Inconel 625 strip using alcohol. Then, wrap the flux powder prepared in Step 2 inside the Inconel 625 strip using a flux-cored wire drawing machine. The diameter of the first drawing die is 2.6 mm. In Step 3, the Inconel 625 strip is the solder 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 29 wt%.

[0098] 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.

[0099] 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.

[0100] The welding wire prepared in Example 5 was used for welding dissimilar materials of heat-resistant steel and stainless steel. The results are as follows:

[0101] (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 heat-resistant steel and stainless steel.

[0102] (2) The tensile strength of the heat-resistant steel-stainless steel dissimilar material joint is 688MPa and the elongation after fracture is 19%.

[0103] (3) The room temperature impact toughness of the heat-resistant steel-stainless steel dissimilar material joint is 107J.

Claims

1. A welding wire for welding dissimilar materials such as heat-resistant steel and stainless steel, characterized in that, It includes a flux core and a solder coating. The flux powder consists of the following components by mass percentage: Cr powder 30-40%, Nb powder 5-10%, V powder 5-6%, Mn powder 2-4%, Si powder 2-4%, Ti powder 1-3%, Co powder 1-3%, CeO2 powder 0.5-1%, Y2O3 powder 0.5-1%, and the remainder is Ni powder. The sum of the mass percentages of the above components is 100%. The solder coating uses Inconel 625 tape. The filler content of the flux-cored wire is controlled at 25 wt% to 30 wt%.

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

3. The welding wire for welding dissimilar materials of heat-resistant steel and stainless steel according to claim 1, characterized in that, The weld bead thickness is 0.3mm and the width is 7mm.

4. The method for preparing welding wire for welding dissimilar materials of heat-resistant steel and stainless steel according to any one of claims 1-3, characterized in that, The specific steps are as follows: Step 1: Weigh out the following components by mass percentage: 30-40% Cr powder, 5-10% Nb powder, 5-6% V powder, 2-4% Mn powder, 2-4% Si powder, 1-3% Ti powder, 1-3% Co powder, 0.5-1% CeO2 powder, 0.5-1% Y2O3 powder, with the remainder being Ni powder. The sum of the mass percentages of the above components should be 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 powder into a powder mixer for thorough mixing for 30min~40min. Step 3: The flux powder prepared in Step 2 is wrapped in an Inconel 625 tape using a flux-cored wire drawing machine. The diameter of the first drawing die is 2.6 mm. 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 welding wire for welding dissimilar materials of heat-resistant steel and stainless steel according to claim 4, characterized in that, In step 1, the purity of each powder is ≥99.9%, and the particle size of each powder is 100~200 mesh.

6. The method for preparing welding wire for welding dissimilar materials of heat-resistant steel and stainless steel according to claim 4, characterized in that, In step 3, the Inconel 625 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 at 25 wt%~30 wt%.

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