CN114260615B - Welding wire for welding T91-TP304H dissimilar materials and preparation method thereof - Google Patents

Abstract

The invention discloses a welding wire for welding T91-TP304H dissimilar materials and a preparation method thereof, wherein the welding wire comprises a flux core and a welding skin, wherein the flux comprises the following components in percentage by mass: 45-50% of Cr powder, 17-20% of Mo powder, 13-15% of Nb powder, 8-10% of V powder, 3-5% of ferromanganese powder, 2-4% of ferrosilicon powder, 1-3% of Al powder and 1-3% of Cu powder, wherein the sum of the mass percentages of the components is 100%. The preparation method comprises the following steps: mixing Cr powder, mo powder, nb powder, V powder, ferromanganese powder, ferrosilicon powder, al powder and Cu powder, drying, wrapping by a pure nickel belt, and drawing to obtain the alloy. The welding joint obtained by the flux-cored wire has excellent obdurability; the flux-cored wire has less alloy elements, simple preparation process and convenient large-scale batch production.

Description

T91-TP304H Welding wire for welding dissimilar materials and its preparation method

technical field

The invention belongs to the technical field of metal material welding, and in particular relates to T91-TP304H welding wire for welding dissimilar materials and a preparation method of the welding wire.

Background technique

The steel used in thermal power plants has strict requirements on material properties. In terms of mechanical properties, it is mainly the strength at room temperature and high temperature. The performance of T91 steel meets the standard of ASME-AS335. The tensile strength at room temperature can reach 770MPa, and it has good plasticity and toughness, good processability and oxidation resistance, and has excellent comprehensive mechanical properties. In terms of physical properties, T91 steel has good thermal conductivity and high heat exchange efficiency, which can reduce the temperature gradient stress of pipes and accessories; it has a low thermal expansion coefficient, and its use can reduce thermal transient stress and thermal expansion stress caused by temperature gradients , can well adapt to the harsh high temperature and high pressure environment of thermal power plants. In addition, due to the excellent performance of T91 steel at high temperatures, reducing the wall thickness of the pipe will not affect its function, so the weight of the pipe can be reduced, the thrust of the pipe on steam turbines and boilers and other equipment can be reduced, the elasticity of the pipe system can be improved, and it is convenient for the pipe processing and installation.

TP304H stainless steel belongs to austenitic heat-resistant steel, which is used to manufacture high-temperature pipes for superheaters and reheaters. It is characterized by high durable strength, excellent oxidation resistance and corrosion resistance. In the piping system of the power plant, as the working temperature of each part is different, the components of the thermal engine unit use various steels with different chemical compositions and structural structures, and welding problems of dissimilar steels will inevitably be encountered. Among them, the connection between T91 and TP304H pipelines is a typical connection form of dissimilar steel in power plants. However, at present, when welding T91 and TP304H, there is no welding material specially matched for connecting dissimilar materials of T91 and TP304H. Due to the differences in thermophysical properties and chemical composition between T91 and TP304H, stress concentration and diffusion of alloy elements are prone to occur during welding and connection, which affects the overall performance. Therefore, it is of great engineering practical significance to develop a welding material specially used for the connection of T91 and TP304H.

Contents of the invention

The object of the present invention is to provide a T91-TP304H welding wire for dissimilar materials, which can solve the problems of unstable performance when welding T91-TP304H dissimilar materials.

Another object of the present invention is to provide a preparation method of T91-TP304H welding wire for welding dissimilar materials.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

A T91-TP304H welding wire for welding dissimilar materials, including a flux core and a weld skin, wherein the flux powder is composed of the following components by mass percentage: Cr powder 45-50%, Mo powder 17-20%, Nb powder 13-15%, 8-10% of V powder, 3-5% of ferromanganese powder, 2-4% of ferrosilicon powder, 1-3% of Al powder, 1-3% of Cu powder, the sum of the mass percentages of the above components is 100%.

The present invention is also characterized in that:

The purity of the eight kinds of metal powders included in the medicinal powder is all more than 99.9%, and the particle size of the eight kinds of metal powders is all 200 mesh.

The welding skin is made of pure nickel strip, the thickness of the pure nickel strip is 0.3mm, and the width is 7mm.

The filling amount of the flux-cored wire is controlled at 35-40wt%.

The second technical scheme adopted by the present invention is a preparation method of T91-TP304H welding wire for welding dissimilar materials, and the specific steps are as follows:

Step 1: Weigh respectively 45-50% of Cr powder, 17-20% of Mo powder, 13-15% of Nb powder, 8-10% of V powder, 3-5% of ferromanganese powder and 2-5% of ferrosilicon powder according to mass percentage. 4%, Al powder 1-3%, Cu powder 1-3%, the sum of the mass percentages of the above components is 100%;

Step 2: Heat the powder weighed in step 1 in a vacuum heating furnace at a heating temperature of 260-300°C and a holding time of 0.5-1h to remove the crystal water in the powder; place the dried powder in a mixing powder Fully mix in the machine, the mixing time is 0.3-0.5h;

Step 3: Use alcohol to remove the grease on the surface of the pure nickel strip, and wrap the drug powder prepared in step 2 in the pure nickel strip through the flux-cored wire drawing equipment, and the aperture of the first drawing abrasive tool is 2.5mm;

Step 4: After the first process is drawn, change the hole diameter of the abrasive tool to 2.3mm, 2.2mm, 2.1mm, 2.0mm, 1.9mm, 1.8mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3 mm, 1.2mm aperture abrasive drawing, the final flux cored wire diameter is 1.2mm;

Step 5: After the flux-cored wire is drawn, it is wound on the wire reel by a wire winding machine, and finally sealed in a flux-cored wire vacuum packaging bag for use.

The third technical scheme adopted in the present invention is to adopt the above-mentioned welding wire to weld the groove form of T91-TP304H dissimilar materials, and open a V-shaped groove, wherein the groove angle on the T91 side is 30°, and the groove angle on the TP304H side is 20°.

The beneficial effect of the present invention is,

(1) Using multi-alloy composite strengthening such as Cr, Mo, Nb, V, etc., can effectively improve the strength and toughness of the weld;

(2) Considering the problem of carburization and decarburization caused by the different Cr content in T91 ferritic steel and TP304H austenitic steel, reasonably design the Cr content in the welding wire, thereby reducing the decarburization and decarburization of the T91 ferritic weld side Carburization on the side of TP304H austenitic stainless steel.

(3) Pulled with pure nickel welding strip, the content of C is low, and the tendency of joint brittleness is small;

(4) The diameter of the flux-cored welding wire of the present invention is relatively small, and the flux-cored welding wire with a wire diameter of 1.2mm is widely applicable, and the flux-cored welding wire can be used for both TIG welding and MIG welding;

(5) When T91-TP304H dissimilar materials are welded, the groove angle on the T91 side is larger than that on the TP304H side, which is mainly set in consideration of the different alloying elements of the base metals on both sides. Compared with TP304H, increasing the T91 side bevel angle can effectively reduce the dilution rate of T91 base metal welding, thereby reducing the problem of decarburization.

(6) The flux-cored welding wire of the present invention has less alloy elements, simple preparation process, and is convenient for large-scale batch production.

Description of drawings

Fig. 1 is the groove structure when T91-TP304H dissimilar materials are welded among the present invention;

Fig. 2 is the flux-cored welding wire prepared in implementation case 2, when T91-TP304H dissimilar materials are welded, the microstructure at the interface between TP1 and the weld seam (corroded by 4% nitric acid alcohol);

Fig. 3 is the microstructure of the welded seam (corroded by aqua regia, cross-section) when the flux-cored welding wire prepared in Example 2 is welded with T91-TP304H dissimilar materials;

Fig. 4 is the flux-cored welding wire prepared in Example 2, when T91-TP304H dissimilar materials are welded, the microstructural morphology of the weld (corroded by aqua regia, longitudinal section);

Fig. 5 shows the impact fracture morphology of the weld seam when the flux-cored welding wire prepared in Example 2 is welded with T91-TP304H dissimilar materials.

Detailed ways

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

The T91-TP304H welding wire for welding dissimilar materials of the present invention includes a flux core and a weld skin, wherein the medicinal powder is composed of the following components in terms of mass percentage: 45-50% of Cr powder, 17-20% of Mo powder, 13-15% of Nb powder, 8-10% of V powder, 3-5% of ferromanganese powder, 2-4% of ferrosilicon powder, 1-3% of Al powder, 1-3% of Cu powder, the sum of the mass percentages of the above components is 100%.

The purity of the eight kinds of metal powders included in the medicinal powder is all more than 99.9%, and the particle size of the eight kinds of metal powders is all 200 mesh.

The welding skin is made of pure nickel strip, the thickness of the pure nickel strip is 0.3mm, and the width is 7mm.

The filling amount of the flux-cored wire is controlled at 35-40wt%.

The functions and functions of each component in the flux-cored wire are as follows:

The welding skin is made of pure nickel strip, the weldability between Ni and the base metal on both sides is good, and the weld mainly composed of Ni has excellent low temperature toughness. In addition, Ni element is a graphitized element, which can increase the activity of carbon atoms, reduce the diffusion rate of carbon and the stability of carbides, and slow down the carbon migration from the low-alloy heat-resistant steel side to the high-alloy steel side.

Cr is the main alloy component of flux-cored wire powder. Cr can expand the α-Fe phase area, close the γ-Fe phase area, and increase A _{by 1} point. Cr can form a substitution solid solution in α-Fe and can be infinitely solid-soluble. Can form carbides strongly. The Cr element has the function of improving the oxidation resistance and corrosion resistance of heat-resistant steel. When the Cr content is less than 5%, it begins to oxidize violently at 600°C, and when the Cr content exceeds 5%, it has good oxidation resistance. The Cr content of the base metal of T91 is about 8-10%. In this application, increasing the Cr content in the weld can effectively improve the occurrence of Cr-poor on the T91 side.

As the main alloying element of flux-cored wire powder, Mo element can also expand the α-Fe phase region, close the γ-Fe phase region, and strongly increase the A ₁ point. Mo can form a replacement solid solution in α-Fe, but it cannot be infinitely dissolved, and is a strong carbide-forming element.

As the main alloying elements of flux-cored wire powder, V and Nb are strong carbide-forming elements. After adding, they can form fine and stable alloy carbides with carbon, and have a strong dispersion strengthening effect. V can expand the α-Fe phase area, close the γ-Fe phase area, and strongly increase the A1 point. V can form a replacement solid solution in α-Fe and can be infinitely solid-soluble. It is also a strong carbide-forming element. Nb can also expand the α-Fe phase region, close the γ-Fe phase region, and strongly raise the A ₁ point.

C is the most obvious solid solution strengthening element in steel. With the increase of C content, the short-term strength of steel increases, and the plasticity and toughness decrease. For ferritic steels such as T91, the increase of C content will accelerate carbonization spheroidization and aggregation speed, accelerate the redistribution of alloy elements, and reduce the weldability, corrosion resistance and oxidation resistance of steel, so in the present invention, pure nickel welding strip is used for drawing, with low C content, and through the rest of the alloy Elemental strengthening to compensate for the loss of strength due to low carbon.

Al is another element added to the flux-cored wire powder. Al can form AlN with N. AlN dissolves into the matrix in large quantities above 1100 ° C, and re-precipitates at lower temperatures, which can play a better dispersion strengthening effect.

A certain amount of Cu element is added to the flux-cored wire powder. Cu element can form a copper-rich phase that is dispersed and precipitated in the austenite matrix during the service of the steel pipe, and closely combined with it. This copper-rich compound plays an excellent role in dispersion strengthening when it meets NbC, NbN, NbCrN and M ₂₃ C ₆ and other compounds.

The preparation method of the above T91-TP304H welding wire for welding dissimilar materials, the specific steps are as follows:

Step 1: Weigh respectively 45-50% of Cr powder, 17-20% of Mo powder, 13-15% of Nb powder, 8-10% of V powder, 3-5% of ferromanganese powder and 2-5% of ferrosilicon powder according to mass percentage. 4%, Al powder 1-3%, Cu powder 1-3%, the sum of the mass percentages of the above components is 100%;

Step 2: Heat the powder weighed in step 1 in a vacuum heating furnace at a heating temperature of 260-300°C and a holding time of 0.5-1h to remove the crystal water in the powder; place the dried powder in a mixing powder Fully mix in the machine, the mixing time is 0.3-0.5h;

Step 3: Use alcohol to remove the grease on the surface of the pure nickel strip, and wrap the drug powder prepared in step 2 in the pure nickel strip through the flux-cored wire drawing equipment, and the aperture of the first drawing abrasive tool is 2.5mm;

Step 4: After the first process is drawn, change the hole diameter of the abrasive tool to 2.3mm, 2.2mm, 2.1mm, 2.0mm, 1.9mm, 1.8mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3 mm, 1.2mm aperture abrasive drawing, the final flux cored wire diameter is 1.2mm;

Step 5: After the flux-cored wire is drawn, it is wound on the wire reel by a wire winding machine, and finally sealed in a flux-cored wire vacuum packaging bag for use.

As shown in Figure 1, when using the above welding wire to weld T91-TP304H dissimilar materials, open a V-shaped groove, where the groove angle on the T91 side is 30°, and the groove angle on the TP304H side is 20°.

Example 1

Step 1: Weigh 45% of Cr powder, 17% of Mo powder, 15% of Nb powder, 8% of V powder, 5% of ferromanganese powder, 4% of ferrosilicon powder, 3% of Al powder and 3% of Cu powder according to mass percentage , the sum of the mass percentages of the above components is 100%;

Step 2: Heat the powder weighed in step 1 in a vacuum heating furnace at a heating temperature of 260°C and a holding time of 0.5h to remove the crystal water in the powder; place the dried powder in a powder mixer for Fully mixed, the mixing time is 0.3h;

Step 3: Use alcohol to remove the grease on the surface of the pure nickel strip, and wrap the drug powder prepared in step 2 in the pure nickel strip through the flux-cored wire drawing equipment, and the aperture of the first drawing abrasive tool is 2.5mm;

Step 4: After the first process is drawn, change the hole diameter of the abrasive tool to 2.3mm, 2.2mm, 2.1mm, 2.0mm, 1.9mm, 1.8mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3 mm, 1.2mm aperture abrasive drawing, the final flux cored wire diameter is 1.2mm;

Step 5: After the flux-cored wire is drawn, it is wound on the wire reel by a wire winding machine, and finally sealed in a flux-cored wire vacuum packaging bag for use.

Use the flux-cored wire prepared in Example 1 to weld T91-TP304H dissimilar materials, and make a V-shaped groove, wherein the groove angle on the T91 side is 30°, and the groove angle on the TP304H side is 20°. Multi-layer and multi-pass welding is adopted, the welding method is TIG welding, the welding current is 80-120A, and the interlayer temperature is controlled at 100-150°C.

After testing, the mechanical properties of the welded joint are: tensile strength 701MPa, elongation after fracture 20%, impact toughness at room temperature 90J.

Example 2

Step 1: Weigh 50% of Cr powder, 20% of Mo powder, 13% of Nb powder, 10% of V powder, 3% of ferromanganese powder, 2% of ferrosilicon powder, 1% of Al powder and 1% of Cu powder according to mass percentage , the sum of the mass percentages of the above components is 100%;

Step 2: Heat the alloy powder weighed in step 1 in a vacuum heating furnace at a heating temperature of 300°C and a holding time of 1 hour to remove the crystal water in the powder; place the dried powder in a powder mixer for Fully mixed, the mixing time is 0.5h;

Step 3: Use alcohol to remove the grease on the surface of the pure nickel strip, and wrap the drug powder prepared in step 2 in the pure nickel strip through the flux-cored wire drawing equipment, and the aperture of the first drawing abrasive tool is 2.5mm;

Step 4: After the first process is drawn, change the hole diameter of the abrasive tool to 2.3mm, 2.2mm, 2.1mm, 2.0mm, 1.9mm, 1.8mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3 mm, 1.2mm aperture abrasive drawing, the final flux cored wire diameter is 1.2mm;

Step 5: After the flux-cored wire is drawn, it is wound on the wire reel by a wire winding machine, and finally sealed in a flux-cored wire vacuum packaging bag for use.

Use the flux-cored wire prepared in Example 2 to weld T91-TP304H dissimilar materials, and make a V-shaped groove, wherein the groove angle on the T91 side is 30°, and the groove angle on the TP304H side is 20°. Multi-layer and multi-pass welding is adopted, the welding method is TIG welding, the welding current is 80-120A, and the interlayer temperature is controlled at 100-150°C.

After testing, the mechanical properties of the welded joint are: tensile strength 731MPa, elongation after fracture 22%, impact toughness at room temperature 94J.

The flux-cored wire prepared in Example 2 is used to weld T91-TP304H dissimilar materials. The appearance of the interface between the welded joint T91 and the weld seam is shown in Figure 2. It can be seen from the figure that due to the corrosion resistance of T91 and TP304 However, after being corroded by 4% nitric acid alcohol, martensitic structure appeared at T91, while the welding seam was made of pure nickel strip with high Ni content and strong corrosion resistance, which did not appear after 4% nitric acid alcohol corrosion Out of organization. Figure 3 shows the microstructure of the weld after being corroded by aqua regia (a mixture of concentrated hydrochloric acid HCl and concentrated nitric acid HNO3 in a volume ratio of 3:1). The weld is mainly composed of columnar dendrite γ phase. Figure 4 is the microstructure morphology of the longitudinal section of the weld. It can be seen from the figure that the section of the columnar dendrite in Figure 3 is an equiaxed structure. Figure 5 shows the fracture morphology of the weld after the impact test. It can be seen that the weld is mainly dimples and has good toughness.

Example 3

Step 1: Weigh 47% of Cr powder, 18% of Mo powder, 14% of Nb powder, 9% of V powder, 4% of ferromanganese powder, 3% of ferrosilicon powder, 2% of Al powder and 3% of Cu powder according to mass percentage , the sum of the mass percentages of the above components is 100%;

Step 2: Heat the alloy powder weighed in step 1 in a vacuum heating furnace at a heating temperature of 280°C and a holding time of 0.7h to remove the crystal water in the powder; place the dried powder in a powder mixer Fully mix, the mixing time is 0.4h;

Step 3: Use alcohol to remove the grease on the surface of the pure nickel strip, and wrap the drug powder prepared in step 2 in the pure nickel strip through the flux-cored wire drawing equipment, and the aperture of the first drawing abrasive tool is 2.5mm;

Step 4: After the first process is drawn, change the hole diameter of the abrasive tool to 2.3mm, 2.2mm, 2.1mm, 2.0mm, 1.9mm, 1.8mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3 mm, 1.2mm aperture abrasive drawing, the final flux cored wire diameter is 1.2mm;

Step 5: After the flux-cored wire is drawn, it is wound on the wire reel by a wire winding machine, and finally sealed in a flux-cored wire vacuum packaging bag for use.

Use the flux-cored wire prepared in Example 3 to weld T91-TP304H dissimilar materials, and make a V-shaped groove, wherein the groove angle on the T91 side is 30°, and the groove angle on the TP304H side is 20°. Multi-layer and multi-pass welding is adopted, the welding method is TIG welding, the welding current is 80-120A, and the interlayer temperature is controlled at 100-150°C.

After testing, the mechanical properties of the welded joint are: tensile strength 722MPa, elongation after fracture 23%, impact toughness at room temperature 89J.

Example 4

Step 1: Weigh respectively 48% of Cr powder, 17.5% of Mo powder, 14.5% of Nb powder, 8% of V powder, 3.5% of ferromanganese powder, 3.5% of ferrosilicon powder, 2.5% of Al powder and 2.5% of Cu powder according to mass percentage , the sum of the mass percentages of the above components is 100%;

Step 2: Heat the alloy powder weighed in step 1 in a vacuum heating furnace at a heating temperature of 270°C and a holding time of 0.8h to remove the crystal water in the powder; place the dried powder in a powder mixer Fully mix, the mixing time is 0.35h;

Step 3: Use alcohol to remove the grease on the surface of the pure nickel strip, and wrap the drug powder prepared in step 2 in the pure nickel strip through the flux-cored wire drawing equipment, and the aperture of the first drawing abrasive tool is 2.5mm;

Step 4: After the first process is drawn, change the hole diameter of the abrasive tool to 2.3mm, 2.2mm, 2.1mm, 2.0mm, 1.9mm, 1.8mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3 mm, 1.2mm aperture abrasive drawing, the final flux cored wire diameter is 1.2mm;

Step 5: After the flux-cored wire is drawn, it is wound on the wire reel by a wire winding machine, and finally sealed in a flux-cored wire vacuum packaging bag for use.

Use the flux-cored wire prepared in Example 4 to weld T91-TP304H dissimilar materials, and make a V-shaped groove, wherein the groove angle on the T91 side is 30°, and the groove angle on the TP304H side is 20°. Multi-layer and multi-pass welding is adopted, the welding method is TIG welding, the welding current is 80-120A, and the interlayer temperature is controlled at 100-150°C.

After testing, the mechanical properties of the welded joint are: tensile strength 739MPa, elongation after fracture 22%, impact toughness at room temperature 94J.

Example 5

Step 1: Weigh 46.5% of Cr powder, 20% of Mo powder, 15% of Nb powder, 8.5% of V powder, 4.5% of ferromanganese powder, 2.5% of ferrosilicon powder, 1.5% of Al powder and 1.5% of Cu powder according to mass percentage , the sum of the mass percentages of the above components is 100%;

Step 2: Heat the alloy powder weighed in step 1 in a vacuum heating furnace at a heating temperature of 290°C and a holding time of 0.9h to remove the crystal water in the powder; place the dried powder in a powder mixer Fully mix, the mixing time is 0.45h;

Step 3: Use alcohol to remove the grease on the surface of the pure nickel strip, and wrap the drug powder prepared in step 2 in the pure nickel strip through the flux-cored wire drawing equipment, and the aperture of the first drawing abrasive tool is 2.5mm;

Step 4: After the first process is drawn, change the hole diameter of the abrasive tool to 2.3mm, 2.2mm, 2.1mm, 2.0mm, 1.9mm, 1.8mm, 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3 mm, 1.2mm aperture abrasive drawing, the final flux cored wire diameter is 1.2mm;

Step 5: After the flux-cored wire is drawn, it is wound on the wire reel by a wire winding machine, and finally sealed in a flux-cored wire vacuum packaging bag for use.

Use the flux-cored wire prepared in Example 5 to weld T91-TP304H dissimilar materials, and make a V-shaped groove, wherein the groove angle on the T91 side is 30°, and the groove angle on the TP304H side is 20°. Multi-layer and multi-pass welding is adopted, the welding method is TIG welding, the welding current is 80-120A, and the interlayer temperature is controlled at 100-150°C.

After testing, the mechanical properties of the welded joint are: tensile strength 737MPa, elongation after fracture 26%, impact toughness at room temperature 95J.

Claims (2)

1. The welding wire for welding the T91-TP304H dissimilar materials is characterized by comprising a flux core and a welding skin, wherein the flux powder comprises the following components in percentage by mass: 45-50% of Cr powder, 17-20% of Mo powder, 13-15% of Nb powder, 8-10% of V powder, 3-5% of ferromanganese powder, 2-4% of ferrosilicon powder, 1-3% of Al powder and 1-3% of Cu powder, wherein the sum of the mass percentages of the components is 100%;

the purity of eight metal powders contained in the medicinal powder is more than or equal to 99.9 percent, and the granularity of the eight metal powders is 200 meshes;

the welding skin adopts a pure nickel strip, the thickness of the pure nickel strip is 0.3mm, and the width of the pure nickel strip is 7mm;

the filling amount of the flux-cored wire is controlled to be 35-40 wt%.

2. The method for preparing the welding wire for welding the T91-TP304H dissimilar materials, which is disclosed by claim 1, is characterized by comprising the following specific steps of:

step 1: respectively weighing 45-50% of Cr powder, 17-20% of Mo powder, 13-15% of Nb powder, 8-10% of V powder, 3-5% of ferromanganese powder, 2-4% of ferrosilicon powder, 1-3% of Al powder and 1-3% of Cu powder according to the mass percent, wherein the sum of the mass percent of the components is 100%;

step 2: heating the powder weighed in the step 1 in a vacuum heating furnace at 260-300 ℃ for 0.5-1h, and removing crystal water in the powder; placing the dried medicinal powder into a powder mixer for fully mixing for 0.3-0.5h;

and step 3: removing grease on the surface of the pure nickel strip by adopting alcohol, wrapping the medicinal powder prepared in the step (2) in the pure nickel strip by using flux-cored wire drawing equipment, wherein the aperture of a first drawing die is 2.5mm;

and 4, step 4: after the drawing of the first procedure is finished, the pore diameters of the dies are changed to 2.3mm,2.2mm,2.1mm,2.0mm,1.9mm,1.8mm,1.7mm,1.6mm,1.5mm,1.4mm,1.3mm and 1.2mm in sequence, and the diameter of the finally obtained flux-cored wire is 1.2mm;

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

Images