CN100393473C - Welding wire for high-strength duplex titanium alloy - Google Patents

Abstract

The invention relates to a welding wire suitable for welding multiple high-strength duplex titanium alloys. The alloy composition of the welding wire is (wt%): Al: 3.0-5.0, Mo: 1.5-3.0, V: 1.5-3.0, Zr: 1.0-2.0, Nb: 3.0-5.0, Hf: 0.1-0.3, Ti: balance . When preparing filler material or welding wire: (alloy Al) Ti, Zr, Hf are added in 0-grade sponge state, Al, Mo, V, Nb are added in the form of Al-based master alloy; melting ingots in vacuum consumable electric arc furnace ≥3 Times; forging, annealing, drawing.

Description

Welding wire for high-strength duplex titanium alloy

technical field

The invention relates to a welding wire suitable for welding various high-strength duplex titanium alloys.

Background technique

At present, when welding medium-strength and high-strength titanium alloys in my country, C∏2 welding wire with a molybdenum equivalent of nearly 2.2 is generally used (the brand is TA20 welding wire after localization), and its chemical composition is (wt%): Al 3.5～4.5, V 2.5～ 3.5, Zr 1.0~2.0, Ti balance. When welding medium-strength titanium alloys with it, welded joints with excellent mechanical properties can be obtained; but when welding high-strength titanium alloys with it, due to the low alloying degree of C∏2 welding wire, the necessary strength of the joint cannot be guaranteed. This trend is more obvious. The present invention aims at this problem, and develops a Ti-Al-Mo-V-Zr-Nb-RE multi-element alloyed welding wire with a molybdenum equivalent of 4.0-6.0, and uses it to weld various high-strength dual-phase titanium alloys to obtain Welded joints with satisfactory strength, plasticity and toughness indicators.

SUMMARY OF THE INVENTION: The object of the present invention is to provide a welding wire suitable for welding various high-strength dual-phase titanium alloys. The technical solution of the present invention is that the alloy composition of the welding wire is (wt%): Al: 3.0-5.0, Mo: 1.5-3.0, V: 1.5-3.0, Zr: 1.0-2.0, Nb: 3.0-5.0, Hf: 0.1 to 0.3, Ti: balance.

The method of preparing welding wire: (1) Alloy Ti, Zr, Hf are added in 0-grade sponge state, Al, Mo, V, Nb are added in the form of Al-based master alloy; (2) Melting ingot in vacuum consumable electric arc furnace ≥ 3 times; (3) Remove the shrinkage cavity of the ingot and turn the skin, then carry out blank forging. The forging specification is: heating temperature 1100±10°C, heat preservation for 60 minutes; (4) Free forging the solder after blank forging into rods The standard for free forging is: heating temperature 950±10°C, holding time: 30-60min, the holding time is shortened with the reduction of the cross section of the bar; (5) Anneal the bar after free forging, anneal The specification is: 700±10°C, heat preservation for 60 minutes, air cooling, and then rolling it into a thin bar on the hot rolling equipment; (6) Drawing the hot rolled thin bar on the wire drawing equipment, during the wire drawing process , continuously annealing the thin rods, the annealing specification is 700±10°C, heat preservation for 20min, air cooling, until it is drawn into the welding wire of the target size. Wire cut the hot rolled foil or strip into the shape and size required by the filling material.

Before using the welding wire, it is vacuum dehydrogenated. After pickling and drying the welding wire, put it into a vacuum furnace for degassing. The pickling solution is: HF+HNO ₃ aqueous solution, dry thoroughly in an oven for at least 3 hours. The specification for vacuum dehydrogenation is: 800±10°C, heat preservation for 180min, and cool with the furnace. The invention is suitable for welding various high-strength dual-phase titanium alloys. Experiments have proved that under the same heat treatment specification, the tensile strength of the welded TC18 titanium alloy is nearly 1200MPa, the nominal composition is Ti-5Al-4.75Mo-4.75V-1Cr-1Fe, and the joint strength is 100% of the base material. The impact toughness is 97% of the base material; the tensile strength of the welded TC21 titanium alloy is greater than 1200MPa, the nominal composition is Ti-6Al-2Sn-2Zr-2.5Mo-1.7Cr-2Nb-0.1Si, and the joint strength is the base material The impact toughness is 100% of that of the matrix material; the tensile strength of the welded TC6 titanium alloy is nearly 1100MPa, and the nominal composition is Ti-6Al-2.5Mo-1.5Cr-0.5Fe-0.3Si. The joint strength is the matrix 110% of the material, and 80% of the impact toughness of the base material. The invention can also be processed into foil or strip, and used as filling material to weld various high-strength dual-phase titanium alloys.

Detailed ways

Selected alloy (wt%): Al: 3.0-5.0, Mo: 1.5-3.0, V: 1.5-3.0, Zr: 1.0-2.0, Nb: 3.0-5.0, Hf: 0.1-0.3, Ti: balance.

The preparation method of welding wire is:

(1) Welding wire composition ratio

Ti, Zr, Hf are added in 0-level sponge state, Al, Mo, V, Nb are added in the form of Al-based master alloy;

(2) Melting ingot

The welding wire ingot is smelted at least three times in a vacuum consumable electric arc furnace to ensure uniform composition.

(3) Blank forging

Remove shrinkage cavities from the ingot, turn the skin, and then carry out billet forging. The forging specification is: heating temperature 1100±10°C, holding temperature for 60 minutes.

(4) Free forging

Free forge the solder after blank forging into a φ14mm bar. The free forging specification is: heating temperature 950±10°C, holding time: 30-60min, and the holding time is shortened with the reduction of the cross section of the bar.

(5) Hot rolling

In order to eliminate the stress and make the structure uniform, the free-forged bar is first annealed. The annealing specification is: 700±10°C, heat preservation for 60min, and air cooling. It is then rolled into thin bars or foil or strip on hot rolling equipment.

(6) Processing of welding wire

The hot-rolled thin bar is drawn on the wire drawing equipment. During the wire drawing process, the thin bar is continuously annealed. The annealing specification is 700±10°C, kept for 20 minutes, and air-cooled until it is drawn as the target. size wire. Wire cut the hot rolled foil or strip into the shape and size required by the filling material.

(7) Vacuum dehydrogenation

Hydrogen has a great influence on the mechanical properties of titanium, especially the impact toughness, so it must be vacuum dehydrogenated before the welding wire is used. After pickling and drying the welding wire, put it into a vacuum furnace for degassing.

The pickling solution is: HF+HNO ₃ aqueous solution, dry thoroughly in an oven for at least 3 hours.

The specification for vacuum dehydrogenation is: 800±10°C, heat preservation for 180min, and cool with the furnace.

Example 1:

Selected alloy (wt%): Al: 5.0, Mo: 1.5, V: 3.0, Zr: 2.0, Nb: 3.0, Hf: 0.1, Ti: balance.

Prepare welding wire:

(1) Welding wire composition ratio

Ti, Zr, Hf are added in 0-level sponge state, Al, Mo, V, Nb are added in the form of Al-based master alloy;

(2) Melting ingot

The welding wire ingot is smelted at least three times in a vacuum consumable electric arc furnace to ensure uniform composition.

(3) Blank forging

Remove shrinkage cavities from the ingot, turn the skin, and then carry out billet forging. The forging specification is: heating temperature 1100±10°C, holding temperature for 60 minutes.

(4) Free forging

Free forge the solder after blank forging into a thin bar. The free forging specification is: heating temperature 950±10°C, holding time: 30-60min, and the holding time is shortened with the reduction of the cross section of the solder.

(5) hot rolling

In order to eliminate the stress and make the structure uniform, the free forged bar is annealed first. The annealing specification is: 700±10°C, heat preservation for 60min, and air cooling. It is then rolled into bars of target dimensions on hot rolling equipment.

(6) Drawing welding wire

The target size bar is drawn on the wire drawing equipment. In order to eliminate work hardening, the bar needs to be continuously annealed. The annealing specification is 700±10°C, heat preservation for 20 minutes, and air cooling until it is drawn to the target size. silk.

(7) Vacuum dehydrogenation

Hydrogen has a great influence on the mechanical properties of titanium, especially the impact toughness, so it must be vacuum dehydrogenated before the welding wire is used. After pickling and drying the welding wire, put it into a vacuum furnace for degassing.

The pickling solution is: HF+HNO ₃ aqueous solution, dry thoroughly in an oven for at least 3 hours.

The specification for vacuum dehydrogenation is: 800±10°C, heat preservation for 180min, and cool with the furnace.

Example 2

Selected alloy (wt%): Al: 3.0, Mo: 3.0, V: 1.5, Zr: 1.0, Nb: 5.0, Hf: 0.3, Ti: balance.

Prepare filling material:

(1) Filling material composition ratio

Ti, Zr, Hf are added in 0-level sponge state, Al, Mo, V, Nb are added in the form of Al-based master alloy;

(2) Melting ingot

The ingots for filling materials are smelted at least three times in a vacuum consumable electric arc furnace to ensure uniform composition.

(3) Blank forging

Remove shrinkage cavities from the ingot, turn the skin, and then carry out billet forging. The forging specification is: heating temperature 1100±10°C, holding temperature for 60 minutes.

(4) Free forging

Free forging the filling material after blank forging into thin bars. The free forging specification is: heating temperature 950±10°C, holding time: 30-60min, and the holding time is shortened with the reduction of the cross section of the filling material.

(5) Hot rolling

In order to eliminate stress and make the structure uniform, the thin bar after free forging is first annealed. The annealing specification is: 700±10°C, heat preservation for 60min, and air cooling. It is then rolled into strip on hot rolling equipment.

(6) Strip processing

The strip is processed into the required shape and size by wire cutting, and it is used as a filler material to transition to the weld seam during the fusion welding of high-strength dual-phase titanium alloy.

(7) Vacuum dehydrogenation

Hydrogen has a great influence on the mechanical properties of titanium, especially the impact toughness, so the filling material must be vacuum dehydrogenated before use. After pickling and drying the filling materials, put them into a vacuum furnace for degassing.

The pickling solution is: HF+HNO ₃ aqueous solution, dry thoroughly in an oven for at least 3 hours.

The specification for vacuum dehydrogenation is: 800±10°C, heat preservation for 180min, and cool with the furnace.

Claims (9)

1. A welding wire for high-strength dual-phase titanium alloy welding, the weight percentage of the alloy composition is: Al: 3.0-5.0, Mo: 1.5-3.0, V: 1.5-3.0, Zr: 1.0-2.0, Nb: 3.0-5.0 , Hf: 0.1～0.3, Ti: balance; the preparation method of welding wire is: (1) Alloy Ti, Zr, Hf are added in 0-level sponge state, Al, Mo, V, Nb are added in the form of Al-based master alloy; (2) Smelting ingots in a vacuum consumable electric arc furnace for more than 3 times; (3) Remove shrinkage cavities from the ingot and turn the skin, then carry out billet forging. The forging specification is: heating temperature 1100±10°C, heat preservation for 60 minutes; (4) Free forge the solder after forging into bars. The free forging specification is: heating temperature 950±10°C, holding time: 30-60min, and the holding time is shortened as the cross-section of the solder decreases; (5) Anneal the free forged bar first, the annealing specification is: 700±10°C, heat preservation for 60min, air cooling, and then roll it into thin bar or foil or strip on hot rolling equipment; (6) Draw the hot-rolled thin bar on the wire drawing equipment. During the wire drawing process, continuously anneal the thin bar. Pull the welding wire to the target size; cut the hot-rolled foil or strip wire into the shape and size required by the filler material. 2. The welding wire for high-strength dual-phase titanium alloy according to claim 1, characterized in that, before the welding wire is used, it is subjected to vacuum dehydrogenation treatment, and after the welding wire is pickled and dried, it is put into a vacuum furnace for degassing ;The pickling solution is: HF+HNO ₃ aqueous solution, thoroughly dried in an oven, the vacuum dehydrogenation specification is: 800±10°C, keep warm for 180min, and cool with the furnace. 3. The welding wire for high-strength dual-phase titanium alloy according to claim 1, its alloy composition is: Al: 4.0, Mo: 2.0, V: 2.0, Zr: 1.5, Nb: 4.0, Hf: 0.2, Ti: balance . 4. The welding wire for high-strength dual-phase titanium alloy according to claim 1, its alloy composition is: Al: 3.0, Mo: 1.5, V: 1.5, Zr: 1.5, Nb: 3.0, Hf: 0.3, Ti: balance . 5. The welding wire for high-strength dual-phase titanium alloy according to claim 1, its alloy composition is: Al: 4.0, Mo: 3.0, V: 2.0, Zr: 1.5, Nb: 5.0, Hf: 0.15, Ti: balance . 6. The welding wire for high-strength dual-phase titanium alloy according to claim 1, its alloy composition is: Al: 5.0, Mo: 2.5, V: 2.2, Zr: 1.5, Nb: 4.0, Hf: 0.2, Ti: balance . 7. The welding wire for high-strength dual-phase titanium alloy according to claim 1, its alloy composition is: Al: 3.0, Mo: 2.0, V: 1.8, Zr: 1.5, Nb: 4.0, Hf: 0.2, Ti: balance . 8. The welding wire for high-strength dual-phase titanium alloy according to claim 1, its alloy composition is: Al: 4.5, Mo: 2.5, V: 2.5, Zr: 1.5, Nb: 4.5, Hf: 0.15, Ti: balance . 9. The welding wire for high-strength dual-phase titanium alloy according to claim 1, characterized in that the welding wire can be processed as a filler material to weld foils or strips of various high-strength dual-phase titanium alloys.