Titanium alloy brazing material and manufacturing method thereof

Abstract

The present invention discloses a titanium alloy brazing material and a method for manufacturing the same. The titanium alloy brazing material comprises an inner core and an outer layer covering the inner core, wherein the outer layer is made of pure titanium and the inner core is titanium-based brazing material powder; the titanium alloy brazing material is in the shape of a wire, and the cross-section of the titanium alloy brazing material is circular or non-circular; the outer diameter of the circle is 1-10 mm. The titanium-based brazing material of the wire-shaped material and other shapes with wire as raw material of the present invention has a simple manufacturing process, high efficiency and greatly reduced cost. Moreover, the composition of the brazing material and the specifications of the brazing ring can be easily changed as needed.

Description

Technical Field

[0001] The invention relates to the field of welding materials, and in particular to a brazing material used for brazing titanium and titanium alloys and a manufacturing method thereof. Background Art

[0002] Titanium alloy is an indispensable structural material in the field of aerospace, and is widely used in the fields of navigation, chemical industry, metallurgy, medical treatment, instrumentation, etc. Brazing is a commonly used manufacturing method for titanium alloy parts and structures. Brazing titanium alloy with titanium-based brazing filler metal can obtain higher joint strength, even reaching or approaching the strength of the parent material, with excellent corrosion resistance and good oxidation resistance, and the operating temperature can reach 600℃. For example, in the aviation manufacturing industry, brazing method is often used for welding various conventional titanium alloy and high-temperature titanium alloy structures, various pipelines, compressor blades, guide vanes and other parts.

[0003] Due to the characteristics of the material itself, it is difficult to prepare filamentary titanium-based brazing filler metals. Therefore, there is no titanium-based brazing filler metal wire supply on the market, and there are no related reports. The common supply methods of titanium-based brazing filler metals are powders, as well as solder pastes and adhesive tapes with powders as raw materials. In situations where welding wire is better, it can only be used in the form of solder paste or adhesive tape, but the organic matter in the solder paste and adhesive tape may have an adverse effect on the welding quality of titanium alloys and the performance of vacuum brazing equipment; in some occasions, such as in a vacuum or atmosphere environment, when high-frequency brazing is used to weld titanium alloy pipes, a powder pressing-sintering method is usually used to prepare a welding ring without an adhesive, and the practice of using wire as a raw material when preparing welding rings such as aluminum brazing filler metals and copper brazing filler metals cannot be adopted. Summary of the invention

[0004] The object of the present invention is to provide a titanium alloy brazing material and a manufacturing method thereof, which is used for low-cost preparation of high-purity titanium-based brazing alloy powder. The method relates to a titanium-based brazing material in a filamentous shape or other shapes using filaments as raw materials, and the manufacturing process is simple, efficient, and the cost is greatly reduced. In addition, the composition of the brazing material and the specifications of the brazing ring can be easily changed according to needs.

[0005] A titanium alloy brazing material, comprising an inner core and an outer layer covering the inner core, wherein the outer layer is made of pure titanium and the inner core is titanium-based brazing filler metal powder;

[0006] The cross section of the titanium alloy brazing material is circular or non-circular;

[0007] The outer diameter of the circle is 1-10 mm.

[0008] Furthermore, the material of the outer pure titanium part is TA1, TA2 or TA3 pure titanium, and the thickness of the outer pure titanium part is 0.05-0.15mm.

[0009] Further, the internal titanium-based brazing filler metal powder is B-Ti92Cu (Cu 7-10wt.%, Ti balance), B-Ti43ZrNi (Zr42-45wt.%, Ni 17-20wt.%, Ti balance), B-Ti48ZrBe (Zr 47-50wt.%, Be 3-5wt.%, Ti balance), B-Ti35ZrNiCu (Zr 34-37wt.%, Ni14-17wt.%, Cu 14-17wt.%, Ti balance), B-Ti43ZrNiBe (Zr42-45wt.%, Ni 11-14wt.%, Be 1-3wt.%, Ti balance), B-Ti57CuZrNi (Zr11-14wt.%, Ni 8-11wt.%, Cu 21-24wt.%, Ti balance), B-Ti38Zr37CuNi (Zr 36-39wt.%, Ni 9-12wt.%, Cu 14-17wt.%, Ti (balance) solder, the particle size of the titanium-based solder powder is 200-500 mesh.

[0010] Furthermore, the internal titanium-based solder powder is one of B-Ti92Cu (containing Cu 8wt.%, balance Ti), B-Ti43ZrNi (containing Zr 43wt.%, Ni 18wt.%, balance Ti), B-Ti48ZrBe (containing Zr 48wt.%, Be 4wt.%, balance Ti), B-Ti35ZrNiCu (containing Zr 35wt.%, Ni15wt.%, Cu 15wt.%, balance Ti), B-Ti43ZrNiBe (containing Zr43wt.%, Ni 12wt.%, Be 2wt.%, balance Ti), B-Ti57CuZrNi (containing Zr 12wt.%, Ni 9wt.%, Cu22wt.%, balance Ti), B-Ti38Zr37CuNi (containing Zr 37wt.%, Ni 10wt.%, Cu 15wt.%, balance Ti) solders,

[0011] Furthermore, the non-circular shape is a triangle, a rectangle, an ellipse or other shapes, and the non-circular shape can be a circle in cross section and only processed into a triangle, a rectangle, an ellipse or other shapes in cross section.

[0012] Furthermore, the titanium alloy brazing material also includes: products of other shapes made from the titanium alloy brazing wire material as raw material, such as welding rings and sheet solder (welding sheets).

[0013] The preparation method of the titanium alloy brazing material comprises the following steps:

[0014] (1) Material preparation: Select pure titanium tubes and titanium-based brazing filler metal powders of appropriate diameters. The material grades of pure titanium tubes are TA1, TA2 or TA3. The outer diameter of the pure titanium tube is 5-20 mm, the wall thickness is 0.1-1.5 mm, and the length is 0.5-5 m. Select annealed pure titanium tubes, and use anhydrous ethanol or acetone to remove oil stains on the inner and outer surfaces of the tubes. Or after ultrasonic cleaning of the pure titanium tubes to remove oil stains, perform recrystallization annealing on the pure titanium tubes under vacuum or argon protection to soften the pure titanium tubes. Annealing is carried out under vacuum at a temperature of 615-730 ° C and a holding time of 30-120 min. Select 200-500 mesh titanium-based brazing filler metal powders.

[0015] (2) Powder filling: Flatten one end of the pure titanium tube, seal the end by arc welding, resistance welding or laser welding, and then fill the titanium-based brazing powder into the pure titanium tube. Vibrate and use a thin rod to insert the powder into the tube to compact the powder to improve the density of the powder in the tube. The relative density of the powder in the titanium tube is ≥40%.

[0016] (3) Sealing welding: Connect the other end of the titanium tube to the vacuum exhaust system and evacuate the vacuum inside the titanium tube to below 0.0067Pa; use resistance welding to weld and seal the titanium tube close to the vacuum system.

[0017] (4) Diameter reduction: Use radial forging equipment - rotary forging machine to stretch and thin the titanium tube. Each time the diameter is reduced to no more than 30%, intermediate annealing is performed. Annealing is carried out under vacuum at a temperature of 615-730℃ and a holding time of 30-120min. The diameter reduction and intermediate annealing processes are carried out alternately until the wire is reduced to the required diameter, and then the final annealing is carried out. The final annealing process is the same as the intermediate annealing.

[0018] Furthermore, when the titanium alloy brazing material is in the form of round wire, it can be used directly; when the titanium alloy brazing material is in the form of non-round wire, the method also includes forming: using round wire as raw material, changing its cross-sectional shape through processing: when a triangular material or an elliptical cross-sectional welding wire is required, drawing or rolling is used for processing; and sheet brazing material can be processed using round wire as raw material. When the titanium alloy brazing material requires annular brazing material, the welding wire is cut according to the circumference of the required ring, and wound into a ring, and the interface of the ring is welded by argon arc spot welding or laser spot welding.

[0019] The present invention provides titanium-based brazing filler metals of different specifications, different cross-sectional shapes, and multiple compositions, or with wire as raw materials, and a preparation method thereof. This titanium-based brazing filler metal avoids the use of harmful organic adhesives during the brazing process; facilitates the arrangement of the brazing filler metal during the titanium alloy brazing process; and can conveniently adjust the shape, specifications, and even composition of the brazing filler metal according to application requirements. For example, this method can be used to prepare a large batch of titanium-based brazing filler metal rings, even of different diameters, at a low cost (compared to the powder pressing-sintering method).

[0020] Instruction Manual

[0021] Figure 1 Photographs of solder wettability and gap filling test in Example 1. DETAILED DESCRIPTION

[0022] The following non-limiting embodiments may enable a person skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0023] Example 1

[0024] The method proposed in the present invention is used to prepare a filamentary titanium-based solder. The diameter of the solder wire is 3 mm. The cross section is circular. The outer ring of the solder cross section is made of TA2 pure titanium material, and the inner part is B-Ti92Cu (containing 8wt.% Cu and the balance Ti) titanium-based solder powder. The wall thickness of the TA1 outer ring is 0.1 mm.

[0025] The preparation method of the welding wire comprises the following steps:

[0026] (1) Material preparation: Select TA2 pure titanium tube and titanium-based brazing filler metal powder of appropriate diameter. The outer diameter of the tube is 10 mm, the wall thickness is 0.5 mm, and the length is 2 m. Use anhydrous ethanol to remove oil stains on the inner and outer surfaces of the tube. Perform recrystallization annealing on the titanium tube in a vacuum tube furnace to soften the titanium tube. The annealing temperature is 650°C and the holding time is 30 min. Use 250-400 mesh titanium-based brazing filler metal powder.

[0027] (2) Powder filling: Flatten one end of the titanium tube and seal it by argon arc welding. Use a funnel to pour titanium-based brazing powder into the pure titanium tube. Vibrate and insert a stainless steel rod into the tube to compact the powder to improve the density of the powder in the tube. The relative density of the powder reaches 40%.

[0028] (3) Sealing welding: Connect the other end of the titanium tube to the vacuum exhaust system. Pump the vacuum inside the tube to below 0.0067Pa. Use resistance welding to weld and seal the titanium tube near the vacuum system.

[0029] (4) Diameter reduction: Use radial forging equipment - rotary forging machine to stretch and thin the titanium tube. The first diameter reduction is to 7mm, and then intermediate annealing is performed. Annealing is carried out in a vacuum tube furnace at a temperature of 650℃ and a holding time of 30min. The second diameter reduction is to 5mm, and then intermediate annealing is performed. Annealing is carried out in a vacuum annealing furnace at a temperature of 650℃ and a holding time of 30min. The third diameter reduction is to 4mm, and then intermediate annealing is performed. Annealing is carried out in a vacuum annealing furnace at a temperature of 650℃ and a holding time of 30min. The fourth diameter reduction is to 3mm, and the final annealing is performed. The final annealing is carried out in a vacuum annealing furnace at a temperature of 650℃ and a holding time of 30min.

[0030] According to this method, a titanium-based brazing wire for brazing is obtained. The melting temperature range (solidus temperature to liquidus temperature) of the brazing material is 795-850°C. The application method of the brazing material is to cut a welding wire of suitable length (or weight) as needed, and then fix it outside the brazing weld by spot welding to perform vacuum brazing of TC4 titanium plate. The vacuum brazing temperature is 920°C. Figure 1 As shown, the brazing filler metal has good wettability and can be completely melted and flow into the weld. The outer fillet of the brazed weld is smooth without corrosion or weld nodules. The shear strength of the brazed sample in the tensile test is 387MPa.

[0031] Example 2

[0032] The method proposed in the present invention is used to prepare a titanium-based solder ring. The diameter of the solder wire is 2.5 mm. The cross section is circular. The outer ring of the solder cross section is made of TA1 pure titanium, and the inner titanium-based solder powder is B-Ti35ZrNiCu (containing Zr35wt.%, Ni15wt.%, Cu15wt.%, Ti balance). The wall thickness of the TA1 outer ring is 0.05 mm.

[0033] The preparation method of the welding wire comprises the following steps:

[0034] (1) Material preparation: Select TA1 pure titanium tube of appropriate diameter and titanium-based brazing filler metal powder. The outer diameter of the tube is 12 mm, the wall thickness is 0.4 mm, and the length is 1 m. Wipe with acetone to remove oil stains on the inner and outer surfaces of the tube. Further clean in an ultrasonic cleaner. Recrystallize and anneal the titanium tube in a vacuum tube furnace to soften it. The annealing temperature is 650°C and the holding time is 30 minutes. Use 250-400 mesh titanium-based brazing filler metal powder.

[0035] (2) Powder filling: Flatten one end of the titanium tube and seal it by resistance welding. Use a funnel to fill the titanium-based brazing powder into the pure titanium tube. The density of the powder in the tube is improved by vibration and by inserting a stainless steel rod into the tube to compact the powder. The relative density of the powder reaches 40%.

[0036] (3) Sealing welding: Connect the other end of the titanium tube to the vacuum exhaust system. Pump the vacuum inside the tube to below 0.0067Pa. Use resistance welding to weld and seal the titanium tube near the vacuum system.

[0037] (4) Diameter reduction: Use radial forging equipment - rotary forging machine to stretch and thin the titanium tube. The first diameter reduction is to 10mm, and then intermediate annealing is performed. Annealing is carried out in a vacuum tube furnace at a temperature of 650℃ and a holding time of 30min. The second diameter reduction is to 8mm, and then intermediate annealing is performed. Annealing is carried out in a vacuum tube furnace at a temperature of 650℃ and a holding time of 30min. The third diameter reduction is to 6mm, and then intermediate annealing is performed. Annealing is carried out in a vacuum annealing furnace at a temperature of 650℃ and a holding time of 30min. The fourth diameter reduction is to 5mm, and then intermediate annealing is performed. Annealing is carried out in a vacuum annealing furnace at a temperature of 650℃ and a holding time of 30min. The fifth diameter reduction is to 4mm, and then intermediate annealing is performed. Annealing is carried out in a vacuum annealing furnace at a temperature of 650℃ and a holding time of 30min. The sixth diameter reduction is to 3mm, and then intermediate annealing is performed. Annealing is carried out in a vacuum annealing furnace at a temperature of 650°C for 30 minutes. The seventh diameter reduction is to 2.5 mm, and the final annealing is carried out. The final annealing is carried out in a vacuum annealing furnace at a temperature of 650°C for 30 minutes.

[0038] (5) Forming: Prepare a welding ring with an inner diameter of 8 mm using wire as raw material. Wrap the welding wire around a round rod with a diameter of 8 mm, wind it into a spiral shape, and then cut the spiral along a plane parallel to the axis of the round rod to obtain multiple rings. Straighten it into a circular ring. Use argon arc spot welding to weld the interface of the ring.

[0039] The melting temperature (solidus to liquidus) of this welding ring is 835-890℃. It is used to weld titanium alloy tubes. Put the welding ring on the TA18 titanium alloy tube with a diameter of 8mm and a wall thickness of 0.75mm, and then put this titanium alloy tube inside the TA18 titanium alloy tube with an inner diameter of 8mm and a wall thickness of 0.75mm. Induction brazing is performed under vacuum. The brazing material has good wettability and completely melts and flows into the weld. The outer fillet of the resulting brazed weld is smooth without corrosion or weld nodules. The weld is dense. The airtightness test is performed and there is no air leakage. The brazed joint of this tube is stretched and broken on the parent material.

Claims

1. A titanium alloy brazing material, characterized in that: The titanium alloy brazing material comprises an inner core and an outer layer covering the inner core, wherein the outer layer is made of pure titanium and the inner core is titanium-based brazing filler metal powder; The pure titanium is TA1, TA2 or TA3, and the thickness of the pure titanium is 0.05-0.15 mm; The titanium-based solder powder is one of B-Ti92Cu, B-Ti43ZrNi, B-Ti48ZrBe, B-Ti35ZrNiCu, B-Ti43ZrNiBe, B-Ti57CuZrNi, and B-Ti38Zr37CuNi solders, and the particle size of the titanium-based solder powder is 200-500 meshes; The B-Ti92Cu contains 7-10wt.% Cu and the balance Ti; the B-Ti43ZrNi contains 42-45wt.% Zr and 17-20wt.% Ni and the balance Ti; the B-Ti48ZrBe contains 47-50wt.% Zr and 3-5wt.% Be and the balance Ti; the B-Ti35ZrNiCu contains 34-37wt.% Zr and 14-17wt.% Cu and the balance Ti; the B-Ti43ZrNiBe contains 42-45wt.% Zr and 11-14wt.% Ni and 11-14wt.% Be and the balance Ti; the B-Ti57CuZrNi contains 11-14wt.% Zr and 8-11wt.% Ni and 21-24wt.% Cu and the balance Ti; the B-Ti38Zr37CuNi contains Zr and 36~39wt.%, Ni 9~12wt.%, Cu 14~17wt.%, Ti balance; The titanium alloy brazing material is in the shape of a wire, and the cross section of the titanium alloy brazing material is circular or non-circular; The outer diameter of the circle is 1-10 mm; The method for preparing the titanium alloy brazing material comprises the following steps: (1) Material preparation: Select pure titanium tubes and titanium-based brazing powder of appropriate diameters; the outer diameter of the pure titanium tube is 5-20 mm and the wall thickness is 0.1-1.5 mm; select annealed pure titanium tubes and use anhydrous ethanol or acetone to remove oil stains on the inner and outer surfaces of the tubes; or after ultrasonic cleaning of the pure titanium tubes to remove oil stains, perform recrystallization annealing on the pure titanium tubes under vacuum or argon protection to soften the pure titanium tubes; (2) Powder filling: Flatten one end of the pure titanium tube, seal the end by arc welding, resistance welding or laser welding, then fill the titanium-based brazing powder into the pure titanium tube and compact the powder so that the relative density of the powder in the titanium tube is ≥40%; (3) Sealing welding: Connect the other end of the titanium tube to the vacuum exhaust system, and evacuate the vacuum inside the titanium tube to below 0.0067Pa. Then, use resistance welding to weld and seal the titanium tube near the vacuum system end. (4) Diameter reduction: Use radial forging equipment - rotary forging machine to stretch and thin the titanium tube. Each time the diameter is reduced to no more than 30%, intermediate annealing is carried out; intermediate annealing is carried out under vacuum at a temperature of 615-730°C and a holding time of 30-120 minutes; diameter reduction and intermediate annealing processes are carried out alternately until the wire is reduced to the required diameter, and then final annealing is carried out; the final annealing process is the same as the intermediate annealing.

2. The titanium alloy brazing material according to claim 1, characterized in that: The non-circular shape is a triangle, a rectangle or an ellipse.

3. The titanium alloy brazing material according to claim 1, characterized in that: A brazing ring made of titanium alloy brazing wire material.

4. The titanium alloy brazing material according to claim 1, characterized in that: In step (1), the annealing is carried out under vacuum at a temperature of 615-730° C. and a holding time of 30-120 min.

5. The titanium alloy brazing material according to claim 1, characterized in that: The radial forging equipment is a rotary forging machine.

6. The titanium alloy brazing material according to claim 1, characterized in that: When the cross-section of the titanium alloy brazing material is circular, it can be used directly; when the cross-section of the titanium alloy brazing material is non-circular, the method also includes forming: using circular wire as raw material, changing the cross-sectional shape, and making a wire with a non-circular cross-section; or using the circular wire as raw material to process it into a sheet-shaped brazing material; when the titanium alloy brazing material is annular, the welding wire is cut according to the required circumference of the ring, and then wound into a circular ring, and the interface of the ring is welded by argon arc spot welding or laser spot welding.

Images