CN112458338B

CN112458338B - Zirconium alloy, preparation method of zirconium alloy and zirconium alloy section

Info

Publication number: CN112458338B
Application number: CN202010286768.5A
Authority: CN
Inventors: 李献军; 张天广; 李刚; 袁瑞; 王家斌; 尹建明; 赵旭东; 雷东平; 汪澜; 胡旭坤; 贾宇航; 杨晶; 王星华; 王成立
Original assignee: State Nuclear Zirconium Phosphate Chemical Testing Co ltd; State Nuclear Bao Ti Zirconium Industry Co
Current assignee: State Nuclear Zirconium Phosphate Chemical Testing Co ltd; State Nuclear Bao Ti Zirconium Industry Co
Priority date: 2020-04-13
Filing date: 2020-04-13
Publication date: 2021-09-14
Anticipated expiration: 2040-04-13
Also published as: CN112458338A

Abstract

Zirconium alloy and preparation method of zirconium alloy and zirconium alloy section bar, wherein the zirconium alloy comprises the following components: 0.2-2.0wt% of A, including 0.2-0.8wt% of molybdenum, and the balance being zirconium; and A is one or more of copper, niobium, vanadium, chromium, cobalt and tin. According to the invention, by controlling the content of the added molybdenum, niobium, copper, vanadium, chromium, cobalt and tin elements, the mechanical strength is improved, and the corrosion resistance of the alloy is improved under the use environments of sulfuric acid, nitric acid, acetic acid, molten alkali and the like and under the oxidation environment of iron-containing ions, copper ions and the like.

Description

Zirconium alloy, preparation method of zirconium alloy and zirconium alloy section

Technical Field

The invention relates to the technical field of material metal, in particular to a zirconium alloy and a preparation method of a zirconium alloy and a zirconium alloy profile.

Background

Zirconium belongs to the passivating metals. Zirconium has a strong affinity with oxygen and can react with oxygen in the air at room temperature to form a dense oxide film with strong adhesion. The oxide film protects the base metal from chemical or mechanical attack and resists corrosion in certain highly corrosive environments including various inorganic acids (e.g., hydrochloric acid, sulfuric acid, nitric acid, etc.), alkalis, most organic acids (e.g., acetic acid, formic acid, etc.), various salt solutions and molten alkalis. However, when the medium contains oxidizing ions (Fe)³⁺，Cu²⁺Etc.), the corrosion rate of zirconium is increased, so the improvement of the corrosion resistance of zirconium material in the oxidizing acid solution environment is the key point. This is also the focus of attention of users of non-nuclear zirconium materials. At the same time, intensity is also another focus of attention for the user. High strength means material savings and no need to rely on increased thickness to meet the requirements in industrial applications.

Therefore, a novel non-nuclear zirconium alloy with improved strength and corrosion resistance is developed, the upgrading and updating of the non-nuclear zirconium alloy are realized, the foreign monopoly situation is broken, and the core competitiveness of the non-nuclear zirconium alloy is mastered.

Disclosure of Invention

Objects of the invention

The invention aims to provide a zirconium alloy and a preparation method of zirconium alloy and zirconium alloy sectional materials, which improve the mechanical strength and the corrosion resistance of the zirconium alloy in the use environments of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, molten alkali and the like and in the oxidation environment of iron-containing ions, copper ions and the like. The zirconium alloy section comprises a zirconium alloy plate, a zirconium alloy pipe, a zirconium alloy rod and a zirconium alloy forging.

(II) technical scheme

To solve the above problems, a first aspect of the present invention provides a zirconium alloy comprising: 0.2-1.9 wt% of copper, 0.2-1.9 wt% of niobium, 0.3-2.0wt% of vanadium, 0.3-1.9 wt% of chromium, 0.4-2.0wt% of cobalt and 0.4-2.0wt% of tin, and further comprises 0.2-0.8wt% of molybdenum, and the balance of zirconium.

The second aspect of the present invention provides a method for preparing a zirconium alloy, which is used for preparing the above zirconium alloy, and comprises: weighing raw materials with required mass, and pressing into an electrode block; carrying out vacuum consumable arc melting on the electrode block to obtain an ingot; and forging the cast ingot to obtain a zirconium alloy blank.

Further, the smelting conditions are that the pre-vacuum degree is less than 3Pa, and the melting temperature is 2200-3000 ℃.

Further, the number of times of smelting is two.

The third aspect of the invention provides a preparation method of a zirconium alloy plate, which comprises the following steps: preparing a zirconium alloy blank by adopting the method; hot rolling the zirconium alloy blank; annealing the hot-rolled zirconium alloy blank at the temperature lower than the phase change point; and carrying out surface treatment on the annealed zirconium alloy blank to obtain the zirconium alloy plate.

Further, the hot rolling condition is that the temperature is 700-.

Further, the rolling process comprises tempering, wherein the tempering temperature is 700-.

The fourth aspect of the invention provides a method for preparing a zirconium alloy pipe, which comprises the following steps: preparing a zirconium alloy blank by adopting the method; processing the zirconium alloy blank to obtain a bar blank with a smooth surface and without cracks and oxide skin; extruding the bar billet to obtain a tube blank; performing multi-pass cold rolling on the tube blank; and annealing the hot-rolled tube blank at the temperature lower than the phase change point to obtain the zirconium alloy tube.

Further, the extruding the bar stock to obtain a tube blank comprises: heating to 850 ℃ by using a resistance furnace or an induction furnace, and keeping the temperature of the resistance furnace for 0.5-3 hours; the heat preservation time of the induction furnace is 1-30 minutes; and (5) extruding after heat preservation to obtain a pipe blank.

Further, the pass reduction rate of the cold rolling is 15-85%.

The fifth aspect of the present invention provides a method for producing a zirconium alloy rod, comprising: preparing a zirconium alloy blank by adopting the method; processing the zirconium alloy blank to obtain a bar blank with a smooth surface and without cracks and oxide skin; forging the bar blank to obtain a bar blank; carrying out multi-pass rolling on the bar stock; and annealing the rolled bar at the temperature lower than the phase change point to obtain the zirconium alloy bar.

Further cooling the rolled material of the bar billet to 600-800 ℃, and keeping the temperature for 0.5-4 hours.

According to the invention, molybdenum is added into zirconium alloy, and an electron vacancy of a molybdenum secondary outer layer is used as a dissolved oxygen receptor and is combined with oxygen to form a passivation film, so that the corrosion current is reduced, the influence of oxide ions is resisted, and the corrosion resistance is improved. In addition, they can effectively reduce H₂Can reduce the adverse effect of elements such as carbon, nitrogen and the like on zirconium, thereby enhancing the corrosion resistance of the zirconium. At the same time, molybdenum forms a second phase in zirconium, the atomic arrangement at the phase interface no longer having integrity. These phase interfaces hinder the slip of dislocations, thus strengthening the material.

Niobium is added into zirconium alloy, electron vacancy of niobium secondary outer layer is used as a dissolved oxygen acceptor, and the niobium secondary outer layer is combined with oxygen to form a passivation film, so that corrosion current is reduced, the influence of oxide ions is resisted, and the corrosion resistance is improved. In addition, the corrosion resistance of the zirconium can be enhanced by effectively reducing the absorption of H2 and reducing the adverse effect of elements such as carbon, nitrogen and the like on the zirconium. While niobium forms a second phase in zirconium, the atomic arrangement at the phase interface no longer has integrity. These phase interfaces hinder the slip of dislocations, thus strengthening the material.

Tin element is added into zirconium alloy, tin atoms fused into solid solution cause lattice distortion, and the lattice distortion increases the resistance of dislocation motion, so that slippage is difficult to carry out, and the strength and hardness of the material are improved. Meanwhile, the addition of tin can eliminate the influence of element elements such as carbon, nitrogen and the like on the strength, particularly the influence of nitrogen elements.

The copper element is added into the zirconium, the cathodic polarization of the copper promotes the zirconium passivation, and the zirconium (alpha-zirconium) is less than 0.2 wt% at normal temperature, so that the Zr can be formed in the alloy₂Cu intermediate compound, Zr₂The Cu intermediate compound can improve corrosion resistance under an oxidizing environment.

Chromium is added to zirconium alloys in which it is present in the form of metal compounds having high strength and hardness. When it is distributed on the metal base body in the form of granular dispersivity, it can greatly raise strength and toughness of said material, and under the condition of oxidizing medium, the chromium can form a layer of firm and compact oxide film on the surface of zirconium, so that the corrosion current can be reduced, and the influence of oxide ion can be resisted to raise corrosion property of zirconium alloy.

Vanadium is added into the zirconium alloy, exists in the zirconium alloy in the form of metal compounds, can refine tissues and grains, improves the coarsening temperature of the grains, improves the strength and plasticity of the zirconium alloy, reduces the impact toughness, forms vanadate with different compositions in an acidic aqueous solution, and has stronger corrosion performance.

The cobalt element is added into the zirconium alloy, so that the toughness of the alloy zirconium alloy is increased, and the addition of the cobalt is a moderate active metal, so that the welding quality and the corrosion resistance of the zirconium alloy are greatly enhanced.

(III) advantageous effects

The technical scheme of the invention has the following beneficial technical effects:

(1) according to the invention, by controlling and adding at least one of molybdenum, niobium, copper, vanadium, chromium, cobalt and tin with preset content, the mechanical strength is improved, and simultaneously, the corrosion resistance of the alloy is improved under the use environments of hydrochloric acid, sulfuric acid, nitric acid, acetic acid and the like and under the oxidation environment of iron-containing ions, copper ions and the like.

(2) The pass processing rate of the invention is 15-85%, which can ensure the smooth rolling; the uneven deformation of the rolled piece is reduced, and the requirement of the product size precision is ensured.

Drawings

FIG. 1 is a schematic flow diagram of a method for preparing a zirconium alloy of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

The invention provides a zirconium alloy, comprising: 0.2-2.0wt% of A, including 0.2-0.8wt% of molybdenum, and the balance being zirconium; and A is one or more of copper, niobium, vanadium, chromium and tin.

According to the invention, molybdenum is added into zirconium alloy, and an electron vacancy of a molybdenum secondary outer layer is used as a dissolved oxygen receptor and is combined with oxygen to form a passivation film, so that the corrosion current is reduced, the influence of oxide ions is resisted, and the corrosion resistance is improved. In addition, the corrosion resistance of the zirconium can be enhanced by effectively reducing the absorption of H2 and reducing the adverse effect of elements such as carbon, nitrogen and the like on the zirconium. At the same time, molybdenum forms a second phase in zirconium, the atomic arrangement at the phase interface no longer having integrity. These phase interfaces hinder the slip of dislocations, thus strengthening the material.

Optionally, the A is copper, and the content of the copper is 0.2-1.9 wt%; or the like, or, alternatively,

the A is niobium, and the content of the niobium is 0.2-1.9 wt%; or the like, or, alternatively,

the A is vanadium, and the content of the vanadium is 0.3-2.0 wt%; or the like, or, alternatively,

the A is chromium, and the content of the chromium is 0.3-1.9 wt%; or the like, or, alternatively,

the A is cobalt, and the content of the cobalt is 0.4-2.0 wt%; or the like, or, alternatively,

the A is tin, and the content of the tin is 0.4-2.0 wt%.

Wherein the copper content is 0.2-1.9 wt%, and may be 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.9 wt%, 1.1 wt%, 1.4 wt%, 1.6 wt%, and 1.9 wt%.

Wherein the content of niobium is 0.2 to 1.9 wt%, and may be 0.2 wt%, 0.5 wt%, 0.7 wt%, 0.9 wt%, 1.1 wt%, 1.3 wt%, 1.5 wt%, 1.6 wt%, 1.8 wt%, and 1.9 wt%.

Wherein the content of vanadium is 0.3-2.0wt%, and may be, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8wt%, 0.9 wt%, and 1.0 wt%.

Wherein the chromium content is 0.3-1.9 wt%, and may be, 0.3 wt%, 0.5 wt%, 0.8wt%, 1.0 wt%, 1.2 wt%, 1.7 wt%, and 1.9 wt%.

Wherein the cobalt content is 0.4-2.0wt%, and may be 0.4 wt%, 0.6 wt%, 0.9 wt%, 0.1.1 wt%, 1.3 wt%, 1.7 wt%, and 2.0 wt%.

Wherein the content of tin is 0.4-2.0wt%, and may be 0.4 wt%, 0.6 wt%, 0.8wt%, 1.1 wt%, 1.4 wt%, 1.7 wt%, and 2.0 wt%.

Wherein the molybdenum content is 0.2-0.8wt%, and may be 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, and 0.8 wt%.

The invention provides a preparation method of a zirconium alloy, which comprises the following steps: weighing raw materials with required mass, and pressing into an electrode block; carrying out vacuum consumable arc melting on the electrode block to obtain an ingot; and forging the cast ingot to obtain a zirconium alloy blank. Wherein the raw material comprises sponge zirconium, ruthenium powder, copper foil/powder or chromium powder.

Preferably, the smelting conditions are that the pre-vacuum degree is less than 3Pa and the melting temperature is 2200-3000 ℃. The pre-vacuum degree is less than 3Pa so as to reduce impurities and improve the purity of the titanium alloy. The melting is carried out by selecting a vacuum arc melting mode, and the temperature of an electrode block during melting is between 2200 and 3000 ℃.

Examples of the invention include the following ratios (see table 1):

TABLE 1

By controlling the content of the added molybdenum, copper, niobium, vanadium, chromium, cobalt and tin elements, the mechanical strength is improved, and the corrosion resistance of the alloy in the use environments of sulfuric acid, nitric acid, acetic acid and the like and in the oxidation environment of iron, copper and the like is improved.

Example 29

FIG. 1 is a flow chart of the preparation of the zirconium alloy of the present invention.

As shown in fig. 1, the following operations were performed on the examples in table 1, including weighing raw materials of desired mass and pressing into electrode blocks. And carrying out vacuum consumable arc melting on the electrode block, controlling the pre-vacuum degree in the melting process to be less than 3Pa and the melting temperature to be 2200-3000 ℃, and obtaining an ingot through secondary vacuum consumable arc melting. And the two end elements of the ingot are analyzed (the results are shown in Table 2). Wherein the raw material comprises sponge zirconium, ruthenium powder, copper foil/powder or chromium powder.

TABLE 2 analysis results of both-end elements of ingot

TABLE 1

As is clear from Table 2, the ingot produced by the method of the present invention has good uniformity.

Example 30

This example provides a method for preparing a zirconium alloy sheet, specifically, an ingot melted in the above example 29 is descaled to obtain an ingot with a diameter of Φ 120 mm. Heating the mixture in a box type resistance furnace to 960 ℃ in the resistance furnace, preserving heat for 1.5 hours, and forging the mixture into a plate blank with the thickness delta 40 mm. After removing the surface oxide skin, heating the plate blank to 800 ℃ in a resistance furnace, keeping the temperature for 1.5 hours, and then performing multi-pass rolling to obtain a plate with the diameter delta 6 mm. And (4) tempering for three times in the middle, wherein the tempering temperature is 800 ℃, and the heat preservation time is 0.5 hour. Delta 6mm sheet material, finished product annealing temperature 600 ℃, time 1.0 hours. After the heat treatment, the oxide skin and the defects are removed through polishing and acid washing. The novel acid corrosion resistant non-nuclear zirconium alloy plate is obtained.

Wherein the raw material comprises sponge zirconium, ruthenium powder, copper foil/powder or chromium powder.

And (3) adding the obtained zirconium alloy plate sample into a strip tensile sample according to the national standard GB/T228.1 machine, and carrying out a room temperature tensile test. The mechanical properties of the materials are shown in Table 3.

TABLE 3 mechanical Property results of the materials

As can be seen from Table 3, the zirconium alloys of examples 1 to 28 of the present invention have very high plastic elongation strength and very high tensile strength, which are far superior to those of the zirconium alloys of comparative examples 1 to 4 and foreign products. The zirconium alloy material can be suitable for plate structures with high requirements on strength.

The model of the foreign product is R60702.

The obtained zirconium alloy plate is put into the solution, and samples with the diameter of 10mm multiplied by 10mm and foreign product samples are subjected to potentiodynamic scanning. The scanning range of the potential is-1.0 to 1.5V, and the scanning speed is 1 mV/s. The corrosion potential E obtained_corrAs shown in table 4.

Solution 1: 50% strength nitric acid.

Solution 2: to 70% strength sulfuric acid, 0.02% by weight of iron ions was added.

Solution 3: to 36% strength acetic acid, 0.05% copper ion was added.

TABLE 4 results of corrosion resistance of materials

As can be seen from Table 4, the zirconium alloys of examples 1 to 28 of the present invention are far superior in corrosion resistance to the zirconium alloys of comparative examples 1 to 4 and foreign products.

Example 31

The embodiment provides a preparation method of a zirconium alloy pipe, which comprises the steps of weighing raw materials with required mass and pressing the raw materials into an electrode block. And carrying out vacuum consumable arc melting on the electrode block, wherein the pre-vacuum degree in the melting process is controlled to be less than 3Pa, and the melting temperature is 2200-3000 ℃. Removing oxide skin from the smelted cast ingot to obtain the cast ingot with the diameter phi of 280 mm. And heating the cast ingot with the removed oxide skin to 1050 ℃ in a resistance furnace, preserving heat for 2 hours, and forging the cast ingot into a rod blank with the diameter of 146 mm. And (3) adding a rotary hole into the bar stock machine, and processing the bar stock machine into an extruded ingot with the diameter phi of 146mm multiplied by the diameter phi of 40 mm. Heating to 680 ℃ by using a resistance furnace, preserving the heat for 2 hours by using the resistance furnace, and then extruding to obtain a tube blank with the diameter of 64 mm. And (4) carrying out three times of cold rolling on the pipe blank with the inner and outer surface treated to obtain a finished pipe with the diameter of 19 mm. The annealing temperature is 550 ℃, and the heat preservation time is 3 hours. And finally preparing the novel acid corrosion resistant non-nuclear zirconium alloy pipe through surface treatment.

Mechanical property tests were conducted on the zirconium alloy pipe samples obtained in examples 25 to 28, and the results are shown in Table 5.

TABLE 5 mechanical Property results for zirconium alloy tubes

As can be seen from table 5, the zirconium alloy tube obtained by the method of the present example has very high plastic elongation strength and very high tensile strength, and can be applied to a tube structure requiring high strength.

Example 32

The embodiment provides a preparation method of a zirconium alloy rod, which comprises the steps of weighing raw materials with required mass and pressing the raw materials into an electrode block. And carrying out vacuum consumable arc melting on the electrode block, wherein the pre-vacuum degree in the melting process is controlled to be less than 3Pa, and the melting temperature is 2200-3000 ℃. Removing oxide skin from the smelted cast ingot to obtain the cast ingot with the diameter phi of 280 mm. And heating the cast ingot with the removed oxide skin to 1050 ℃ in a resistance furnace, preserving heat for 2 hours, and forging the cast ingot into a bar blank with the diameter of phi 55 mm. Rolling into bar with the diameter of 16mm in multiple passes, and annealing the finished product at 650 ℃ for 1.0 hour. And after the heat treatment, removing the defects by acid washing.

The zirconium alloy rods obtained in examples 25 to 28 were subjected to a room temperature tensile test. The mechanical properties of the materials are shown in Table 6

TABLE 6 mechanical Property results for zirconium alloy tubes

As is clear from table 6, the zirconium alloy rods produced by the method of the present example have very high strength and elongation, and can be applied to the rod material required for strength and plasticity.

It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.

Claims

1. The zirconium alloy is characterized by comprising 0.2-0.8wt% of molybdenum, 0.2-2.0wt% of A and the balance of zirconium; the A is vanadium or cobalt, wherein,

electron vacancies of the molybdenum secondary outer layer are used as a receptor of dissolved oxygen and are combined with oxygen to form a passivation film;

the content of the vanadium is 0.3-2.0 wt%;

the content of cobalt is 0.4-2.0 wt%.

2. A method for preparing the zirconium alloy of claim 1, comprising:

weighing raw materials with required mass, and pressing into an electrode block;

carrying out vacuum consumable arc melting on the electrode block to obtain an ingot;

and forging the cast ingot to obtain a zirconium alloy blank.

3. The method of claim 2,

the smelting times are two times.

4. A preparation method of a zirconium alloy plate is characterized by comprising the following steps:

preparing a zirconium alloy blank by the method of claim 2 or 3;

hot rolling the zirconium alloy blank;

annealing the hot-rolled zirconium alloy blank at the temperature lower than the phase change point;

and carrying out surface treatment on the annealed zirconium alloy blank to obtain the zirconium alloy plate.

5. The method of claim 4,

the hot rolling condition is that the temperature is 700-.

6. The method as claimed in claim 4, wherein the rolling process comprises tempering, wherein the tempering temperature is 700 ℃ and 800 ℃, and the holding time is 0.5-2 hours.

7. A preparation method of a zirconium alloy pipe is characterized by comprising the following steps:

preparing a zirconium alloy blank by the method of claim 2 or 3;

processing the zirconium alloy blank to obtain a bar blank with a smooth surface and without cracks and oxide skin;

extruding the bar billet to obtain a tube blank;

performing multi-pass cold rolling on the tube blank;

and annealing the hot-rolled tube blank at the temperature lower than the phase change point to obtain the zirconium alloy tube.

8. The method of claim 7, wherein extruding the billet to produce a tube blank comprises:

heating to 850 ℃ by using a resistance furnace or an induction furnace, and keeping the temperature of the resistance furnace for 0.5-3 hours; the heat preservation time of the induction furnace is 1-30 minutes;

and (5) extruding after heat preservation to obtain a pipe blank.

9. The method of claim 7, wherein the cold rolling pass reduction is 15-85%.

10. A method for producing a zirconium alloy rod, comprising:

preparing a zirconium alloy blank by the method of claim 2 or 3;

forging and rolling the zirconium alloy blank for multiple times;

annealing the rolled zirconium alloy blank at the temperature lower than the phase change point;

and carrying out surface treatment on the annealed zirconium alloy blank to obtain the zirconium alloy bar.