CN111318835A - Nickel-based alloy welding wire for high-temperature alloy fusion welding and preparation method and application thereof - Google Patents

Abstract

The invention discloses a nickel-based alloy welding wire for high-temperature alloy fusion welding, a preparation method and application thereof, and belongs to the technical field of high-temperature alloy fusion welding materials. The chemical composition of the welding wire (wt.%): C 0～1%, Cr 5.0～25.0%, Co 1.5～25.5%, Al 1～12.5%, W 0.5～20.5%, Mo 1.5～10.5%, Nb 0.8～12.5 %, Y 0-1.0%, Fe 0-1.0%, Si 0-2.0%, Ni is the balance. The welding wire is prepared by the directional solidification method and is used for fusion welding of high temperature alloys. The welding current is 20‑35A and the voltage is 10‑12V. The invention solves the problem of repairing the casting defects of the precipitation-strengthened nickel-based superalloy and the current situation that the nickel-based superalloy is difficult to prepare due to the strong deformation resistance of the nickel-based superalloy, and has important application value.

Description

A kind of nickel-based alloy welding wire for high temperature alloy fusion welding and its preparation method and application

technical field

The invention relates to the technical field of high-temperature alloy connection, in particular to a nickel-based alloy welding wire for high-temperature alloy fusion welding, a preparation method and application thereof, and the welding wire is suitable for high-temperature alloy fusion welding connection.

Background technique

With the development of integral precision casting technology, cast superalloys are gradually being widely used in the aerospace industry. However, as the air inlet temperature and thrust-weight ratio before the turbine of advanced aero-engines become higher and higher, and the requirements for engine weight reduction are becoming more and more stringent. As the structure of superalloy structural parts is becoming more and more complex, the precision is getting higher and higher, and the manufacturing difficulty is increasing. The final structure cannot be realized by precision casting alone, and must be combined with reliable welding technology and other advanced manufacturing It can realize the split casting of superalloy structural parts. In addition, the fusion welding method can not only realize the connection of the superalloy structural parts, but also realize the repair of defects, which can effectively improve the working reliability and economy of the aero-engine. In general, nickel-based superalloys have excellent high-temperature performance, but superalloys contain high melting point elements such as Al, Ti, W, and Mo, which are relatively high in solder. The welding position of superalloy structural parts must have excellent temperature bearing capacity, and there must be no welding defects. Among the existing welding wires in my country, there are few welding wires that can be used for high-temperature alloys, especially nickel-based high-temperature alloys with excellent high-temperature performance. As long as cracks are easily formed during welding of high-temperature alloys, they cannot meet the requirements for use. Moreover, the welding wire materials for high-performance welding of superalloys are usually similar in chemical composition to superalloys, have excellent high-temperature strength, and have strong high-temperature deformation resistance, and cannot be prepared into wires by traditional drawing methods. Therefore, it is urgent to develop a nickel-based alloy wire material for superalloy fusion welding to meet the welding requirements of superalloy parts.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a nickel-based alloy welding wire material for high-temperature alloy fusion welding and a preparation method. The prepared welding wire has a composition similar to that of the nickel-based high-temperature alloy base material, which can effectively solve the problems of high-temperature alloy casings and other parts used in harsh environments. The connection and repair of components has important application value.

For achieving the above object, technical scheme of the present invention is as follows:

A nickel-based alloy welding wire for high-temperature alloy fusion welding, the welding wire is a nickel-based alloy wire, and the chemical composition of the welding wire is as follows in terms of weight percentage:

C 0～1%, Cr 5.0～25.0%, Co 1.5～25.5%, Al 1～12.5%, W 0.5～20.5%, Mo1.5～10.5%, Nb 0.8～12.5%, Y 0～1.0%, Fe 0 to 1.0%, Si 0 to 2.0%, and Ni is the balance.

By weight percentage, the preferred chemical composition of the welding wire is as follows:

C 0.1～1%, Cr 5.0～25.0%, Co 1.5～25.5%, Al 1～12.5%, W 0.5～20.5%, Mo 1.5～10.5%, Nb 0.8～12.5%, Y 0.1～1.0%, Fe 0.1 ～1.0%, Si 0.5～2.0%, Ni is the balance.

The welding wire is a cylindrical wire with a diameter of 1-2 mm and a length greater than 200 mm.

The preparation method of the nickel-based alloy welding wire for high-temperature alloy fusion welding includes the following steps:

(1) according to the chemical composition batching of described welding wire, adopt vacuum induction furnace to smelt out master alloy ingot;

(2) The master alloy ingot is melted in a directional solidification furnace, and the molten master alloy melt is poured into an alumina ceramic shell. After filling, the ceramic shell is pulled from the furnace at a certain speed into a room temperature vacuum chamber, To achieve directional solidification of the welding wire;

(3) Breaking the solidified and cooled ceramic shell, taking out the welding wire, removing the welding wire and removing the oxide scale on the centerless grinding, thus obtaining the welding wire product.

In step (1), the smelting process is as follows: firstly heating to 1550-1600°C for 1 min, then heating to 1450-1550°C for 10min, then heating to 1300-1400°C for 10min, and pouring at 1400-1450°C.

In step (2), the melting temperature is 1400-1600° C., and the molten master alloy liquid is injected into the alumina ceramic shell.

In step (2), 100-200 cylindrical cavities with diameters of 1.1-2.1 mm are distributed inside the alumina ceramic shell.

In step (2), in the process of pulling the ceramic shell, the pulling speed is controlled to be 1-10 mm/min, so as to ensure the formability of the welding wire.

The nickel-based alloy welding wire for fusion welding of superalloys is used for fusion welding of precipitation-strengthened nickel-based superalloys. During the fusion welding process, the welding wire is placed between two base metals to be welded, and after being fixed with a clamp, the fixing clamp is The loaded sample is placed in a vacuum fusion welding furnace for fusion welding, the welding current is 20-35A, and the voltage is 10-12V.

After the fusion welding connection, there is no grain boundary in the connection joint, and the composition of the weld zone is similar to that of the precipitation-strengthened nickel-based superalloy to be connected. The lasting life of ≥ 100h.

The design idea and principle of the present invention are as follows:

In order to solve the problem of repairing casting defects of precipitation-strengthened nickel-based superalloys, a high-performance welding wire material for nickel-based superalloys was developed. The composition of the welding wire is similar to that of precipitation-strengthened nickel-based superalloys. . However, in view of the current situation that nickel-based superalloys have strong deformation resistance, making it difficult to prepare nickel-based superalloy welding wires, the present invention, in terms of component design, reduces elements that increase crack sensitivity such as Al and W within a certain range, and improves Cr , Co and other elements that increase the plasticity of the alloy and reduce the crack sensitivity. In addition, considering that Nb replaces Ta is beneficial to improve the plasticity, the addition of C slightly increases the crack sensitivity of the heat-affected zone, while the addition of B significantly improves the crack sensitivity. The content of several elements is properly adjusted, so as to obtain the welding wire material with high welding strength and good weldability.

The beneficial effects of the present invention are:

By adopting the nickel-based superalloy welding wire and the fusion welding process prepared by the invention, there are no cracks in the obtained welded joints, so as to avoid failure under high-temperature service conditions, and the melting welding temperature is high, the fluidity is moderate, and the corrosion to the base material is small, and the welding joints are less corrosive. The mechanical properties are close to the base material, and compared with the traditional high-temperature fusion welding material, the fusion welding material of the present invention is more suitable for fusion welding of nickel-based single crystal superalloy.

Description of drawings

Fig. 1 shows the microstructure of the joint of K4951 alloy by fusion welding of the welding wire prepared in Example 1; wherein: (a) is the microscopic appearance; (b) is a macroscopic photo.

FIG. 2 shows the joint microstructure of fusion-welded K4951 alloy in Comparative Example 1. FIG.

FIG. 3 shows the joint microstructure of fusion-welded K4951 alloy in Comparative Example 2. FIG.

Detailed ways

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

Example 1

The base material to be welded in this embodiment is a nickel-based superalloy K4951.

The chemical composition of the welding wire in this embodiment is (wt.%): C 0.8%, Cr 15.0%, Co 15.5%, Al 8.5%, W5.5%, Mo 4.5%, Nb 4.5%, Y 0.5%, Fe 0.5%, Si 0.5%, the rest is Ni, the master alloy ingot is smelted by a vacuum melting furnace, and the master alloy ingot is smelted by a vacuum induction furnace. A master alloy ingot was prepared.

Welding wire preparation method: The master alloy ingot is melted in a directional solidification furnace, and the melting temperature is 1400 ° C. The molten master alloy liquid enters the alumina ceramic shell with a cavity diameter of 2.1 mm through the liquid outlet. The ceramic shell is pulled out, and the pull-out speed is 1mm/min, and the directional solidification is carried out; the solidified and cooled ceramic shell is broken, the welding wire is taken out, and the oxide scale is removed on the welding wire on the centerless grinding, that is, the welding wire material with a diameter of 2 mm is obtained. .

Welding method: Before welding, a sample of solid solution nickel-based superalloy K4951 was polished with 800 grit sandpaper on the surface to be welded, ultrasonically cleaned in acetone for 15 minutes to remove the oil stain on the surface of the sample to be welded, and the welding wire was placed on the base metal to be welded. During the time, after fixing with a fixture, smear the surface of the sample with aluminum oxide powder as a flow blocking agent to prevent the loss of solder during the fusion welding process. During welding, the welding current is 20A and the voltage is 10V. and aging treatment. After fusion welding, there is no grain boundary in the joint, the composition of the weld zone is similar to that of K4951 alloy, the tensile strength is 80% of that of K4951 alloy, and the durable life at 980℃/66MPa is 125h.

Example 2

The base material to be welded in this embodiment is a nickel-based superalloy K4951.

The chemical composition of the welding wire in this embodiment is (wt.%): C 0.5%, Cr 5.0%, Co 1.5%, Al 2.5%, W2.5%, Mo 1.5%, Nb 1.8%, Y 0.5%, Fe 0.5%, Si 0.3%, the rest is Ni, the master alloy ingot is smelted by a vacuum melting furnace, and the master alloy ingot is smelted by a vacuum induction furnace. , the master alloy ingot was obtained.

Welding wire preparation method: The mother alloy ingot is melted in a directional solidification furnace, and the melting temperature is 1600 ° C. The molten mother alloy liquid enters the alumina ceramic shell with a cavity diameter of 1.1 mm through the liquid outlet. The ceramic shell is pulled out, and the pull-out speed is 1mm/min, and the directional solidification is carried out; the solidified and cooled ceramic shell is broken, the welding wire is taken out, and the oxide scale is removed from the welding wire on the centerless grinding, that is, the welding wire material with a diameter of 1 mm is obtained. .

Welding method: Before welding, a sample of solid solution nickel-based superalloy K4951 was polished with 800 grit sandpaper on the surface to be welded, ultrasonically cleaned in acetone for 15 minutes to remove the oil stain on the surface of the sample to be welded, and the welding wire was placed on the base metal to be welded. During the time, after fixing with a fixture, apply a flow blocking agent alumina powder on the surface of the sample to prevent the loss of solder during the fusion welding process. During welding, the welding current is 25A and the voltage is 12V. and aging treatment. After fusion welding, there is no grain boundary in the joint, and the composition of the weld zone is similar to that of K4951 alloy.

Example 3

The base material to be welded in this embodiment is a nickel-based superalloy K4951.

The chemical composition of the welding wire in this embodiment is (wt.%): C 0.3%, Cr 10.0%, Co 2.5%, Al 4.5%, W7.5%, Mo 8.5%, Nb 7.5%, Y 0.5%, Fe 0.3%, Si0.5%, the rest is Ni, the master alloy ingot is smelted by vacuum melting furnace, and the master alloy ingot is smelted by vacuum induction furnace. The melting process is: 1575℃/1min→1475℃/10min→1350℃/10min→1450℃ pouring , the master alloy ingot was obtained.

Welding wire preparation method: The mother alloy ingot is melted in a directional solidification furnace, and the melting temperature is 1500 ° C. The molten mother alloy liquid enters the alumina ceramic shell with a cavity diameter of 1.9 mm through the liquid outlet. The ceramic shell is pulled out, and the pull-out speed is 1 mm/min, and directional solidification is performed; the solidified and cooled ceramic shell is broken, the welding wire is taken out, and the oxide scale is removed on the welding wire on the centerless grinding, that is, the welding wire with a diameter of 1.8 mm is obtained. Material.

Welding method: Before welding, a sample of solid solution nickel-based superalloy K4951 was polished with 800 grit sandpaper on the surface to be welded, ultrasonically cleaned in acetone for 15 minutes to remove the oil stain on the surface of the sample to be welded, and the welding wire was placed on the base metal to be welded. During the time, after fixing with a fixture, smear the surface of the sample with aluminum oxide powder as a flow blocking agent to prevent the loss of solder during the fusion welding process. During welding, the welding current is 22A and the voltage is 10V. and aging treatment. After fusion welding, there is no grain boundary in the joint, and the composition of the weld zone is similar to that of K4951 alloy.

Comparative Example 1

The base metal to be welded in this example is a nickel-based superalloy K4951.

Welding wire preparation method: The K4951 ingot is melted in a directional solidification furnace, and the melting temperature is 1450 ° C. The molten mother alloy liquid enters the alumina ceramic shell with a cavity diameter of 2.1 mm through the liquid outlet. The shell is pulled out at a pull-out speed of 1 mm/min, and directional solidification is carried out; the solidified and cooled ceramic shell is broken, the welding wire is taken out, and the oxide scale is removed on the welding wire on a centerless grinding, that is, the welding wire material with a diameter of 2 mm is obtained.

Before welding, the sample of solid solution nickel-based superalloy K4951 was polished with 800 grit sandpaper on the surface to be welded, ultrasonically cleaned in acetone for 15 minutes to remove the oil stain on the surface of the sample to be welded, and the welding wire was placed between the base metals to be welded. After the fixture is fixed, the surface of the sample is smeared with alumina powder as a flow blocking agent to prevent the loss of solder during the fusion welding process. During welding, the welding current is 22A and the voltage is 10V. and aging treatment. After fusion welding, there is no grain boundary in the joint, and the composition of the weld zone is similar to that of K4951 alloy.

Comparative Example 2

The base metal to be welded in this example is a nickel-based superalloy K4951.

Welding wire preparation method: the K4951 ingot is machined to obtain welding wire material.

Before welding, the sample of solid solution nickel-based superalloy K4951 was polished with 800 grit sandpaper on the surface to be welded, ultrasonically cleaned in acetone for 15 minutes to remove the oil stain on the surface of the sample to be welded, and the welding wire was placed between the base metals to be welded. After the fixture is fixed, the surface of the sample is smeared with alumina powder as a flow blocking agent to prevent the loss of solder during the fusion welding process. During welding, the welding current is 22A and the voltage is 10V. and aging treatment. After fusion welding, there is no grain boundary in the joint, the composition of the weld zone is similar to that of K4951 alloy, the tensile strength is 40% of that of K4951 alloy, and the durable life at 980℃/66MPa is 40h.

It can be seen from the microstructure and macroscopic photos of the fusion welded joint of the sample in the above embodiment (Fig. 1) that there is no crack in the welded joint, which avoids failure under high temperature service conditions. The composition of the welded seam area of the sample after welding in the example is similar to that of the K4951 alloy, the tensile strength reaches more than 80% of that of the K4951 alloy, and the lasting life at 980°C/66MPa is more than 100h. It shows that compared with the traditional superalloy fusion welding material, the fusion welding wire of the present invention is more suitable for the fusion welding of nickel-based single crystal superalloy.

It can be seen from the microstructure diagrams of the fusion welded joints of the samples in the above comparative examples (Figure 2-Figure 3) that compared with the examples, there are more cracks in the fusion welded joints, which will reduce the high temperature performance of the joints. . It can be seen from the tensile strength test results of the samples after connection in the comparative example that the tensile strength and lasting life of welded joints after connection cannot meet the tensile strength requirements of the joints.

Claims (10)

1. The nickel-based alloy welding wire for the high-temperature alloy fusion welding is characterized in that: the welding wire is a nickel-based alloy wire material, and comprises the following chemical components in percentage by weight:

0-1% of C, 5.0-25.0% of Cr, 1.5-25.5% of Co, 1-12.5% of Al, 0.5-20.5% of W, 1.5-10.5% of Mo, 0.8-12.5% of Nb, 0-1.0% of Y, 0-1.0% of Fe, 0-2.0% of Si, and the balance of Ni.

2. The nickel-based alloy welding wire for superalloy fusion welding according to claim 1, wherein: the welding wire comprises the following chemical components in percentage by weight:

0.1-1% of C, 5.0-25.0% of Cr, 1.5-25.5% of Co, 1-12.5% of Al, 0.5-20.5% of W, 1.5-10.5% of Mo1, 0.8-12.5% of Nb, 0.1-1.0% of Y, 0.1-1.0% of Fe, 0.5-2.0% of Si, and the balance of Ni.

3. The nickel-based alloy welding wire for superalloy fusion welding according to claim 1, wherein: the welding wire is a cylindrical wire with the diameter of 1-2mm, and the length of the welding wire is more than 200 mm.

4. The method for preparing a nickel-based alloy welding wire for superalloy fusion welding according to claim 1, wherein: the method comprises the following steps:

(1) preparing materials according to the chemical components of the welding wire, and smelting a master alloy ingot by adopting a vacuum induction furnace;

(2) melting a master alloy ingot by adopting a directional solidification furnace, pouring the molten master alloy melt into an alumina ceramic shell, and after the alumina ceramic shell is fully filled, drawing the ceramic shell from the furnace at a certain speed into a room-temperature vacuum chamber to realize directional solidification of a welding wire;

(3) and crushing the solidified and cooled ceramic shell, taking out the welding wire, removing the welding wire, and removing oxide skin on a centerless grinder to obtain the welding wire product.

5. The method for preparing a nickel-based alloy welding wire for superalloy fusion welding according to claim 4, wherein: in the step (1), the smelting process comprises the following steps: heating to 1550-1600 ℃ and preserving heat for 1min, then heating to 1450-1550 ℃ and preserving heat for 10min, then heating to 1300-1400 ℃ and preserving heat for 10min, and pouring at 1400-1450 ℃.

6. The method for preparing a nickel-based alloy welding wire for superalloy fusion welding according to claim 4, wherein: in the step (2), the melting temperature is 1400-1600 ℃, and the melted mother alloy liquid is injected into the alumina ceramic shell.

7. The method for preparing a nickel-based alloy welding wire for superalloy fusion welding according to claim 4, wherein: in the step (2), 100-200 cylindrical cavities with the diameter of 1.1-2.1mm are distributed in the alumina ceramic shell.

8. The method for preparing a nickel-based alloy welding wire for superalloy fusion welding according to claim 4, wherein: in the step (2), in the process of drawing the ceramic shell, the drawing speed is controlled to be 1-10 mm/min so as to ensure the formability of the welding wire.

9. Use of the nickel-based alloy welding wire for superalloy fusion welding according to claim 1, wherein: the welding wire is adopted to carry out fusion welding of the precipitation strengthening nickel-based high-temperature alloy, the welding wire is placed between two base metals to be welded in the fusion welding connection process, after the welding wire is fixed by a clamp, a sample which is fixedly clamped is placed in a vacuum fusion welding furnace to carry out fusion welding, the welding current is 20-35A, and the voltage is 10-12V.

10. The nickel-based alloy welding wire for superalloy fusion welding according to claim 8, wherein: after fusion welding connection, no crystal boundary exists in the connection joint, the components of a welding seam area are similar to those of the precipitation strengthening nickel-based high-temperature alloy to be connected, the tensile strength can reach more than 80% of that of the precipitation strengthening nickel-based high-temperature alloy, and the lasting life of 980 ℃ and 66MPa is more than or equal to 100 h.

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