CN106032559A - Corrosion-resistant high-nickel alloy and manufacturing method thereof - Google Patents

Abstract

The invention relates to a corrosion-resistant high-nickel alloy and its manufacturing method. The corrosion-resistant high-nickel alloy is calculated based on its total weight of 100wt%, including 99.6~99.9wt% nickel, 0.03~0.12wt% titanium, 0.003~0.02wt% carbon and the rest with a total weight less than 0.3wt% Impurity elements, the impurity elements include at least manganese, iron, silicon, cobalt and copper. By adding a small amount of titanium element, the present invention can form a secondary phase in which impurities such as carbon, manganese, iron and silicon gather inside the high-nickel alloy grains, thereby reducing the carbon content on the grain boundaries and the overall impurity concentration in the alloy, thereby preventing crystallization. graphitization and improve the corrosion resistance of the alloy.

Description

Corrosion-resistant high-nickel alloy and manufacturing method thereof

technical field

The invention relates to an alloy, in particular to a corrosion-resistant high-nickel alloy and a manufacturing method thereof.

Background technique

Nickel metal is a material with a high melting point (about 1453°C). It has a stable face-centered cubic structure below the melting point, and it is easy to accommodate other alloying elements in solid solution, making it not only excellent in ductility, but also conductive and It also has good thermal conductivity and is magnetic at room temperature, so it is widely used in industry. Table 1 shows the basic properties of pure nickel.

Table 1. Basic properties of pure nickel

nature pure nickel Density (g/cm ³ ) 8.89 Thermal conductivity (W/mk) 70.2 20-95℃ thermal expansion coefficient (10 ^-6 /K) 13.3 20℃Resistivity(mOhm.cm) 9.6 Cold pumping treatment (N/mm ² ) 462 Elongation% >40 Curie temperature(℃) 360

High-nickel alloy products for industrial use are called nickel metals with a nickel content greater than 99.0wt%. They are also commonly referred to as pure nickel for industrial use. They are usually used in environments with temperatures lower than 315°C, such as caustic alkali such as food and artificial fibers. Environmental use to guarantee the purity of the product produced.

It is known that elements such as carbon, iron, manganese, silicon, etc. are usually added to help degassing in order to prevent high-nickel alloys from producing porosity defects. However, although the addition of these elements can reduce the occurrence of porosity defects, it will have an adverse effect on the properties of high-nickel alloys. For example, the addition of carbon will make the alloy material prone to intergranular graphitization at high temperature, resulting in a decrease in mechanical properties, and the corrosion resistance will also be greatly reduced with the addition of impurity elements such as iron, manganese, and silicon.

Therefore, it is necessary to provide an innovative and progressive corrosion-resistant high-nickel alloy and a manufacturing method thereof to solve the above-mentioned problems.

Contents of the invention

The invention provides a corrosion-resistant high-nickel alloy. The high-corrosion-nickel alloy includes 99.6-99.9wt% nickel, 0.03-0.12wt% titanium, 0.003-0.02wt% Carbon and other impurity elements whose total weight is less than 0.3wt%, said impurity elements at least include manganese, iron, silicon, cobalt and copper.

The present invention provides a kind of manufacture method of corrosion-resistant high-nickel alloy in addition, it comprises the following steps:

(a) Provide alloy ingredients, the alloy ingredients are calculated based on the total weight of 100wt%, including 99.5-99.9wt% nickel, 0.05-0.3wt% titanium, 0.005-0.1wt% carbon and other impurity elements , the impurity elements include at least manganese, iron, silicon, cobalt and copper; and

(b) smelting the alloy ingredients to produce a corrosion-resistant high-nickel alloy, which includes 99.6-99.9wt% nickel, 0.03-0.12wt% nickel and 0.03-0.12wt% titanium, 0.003-0.02wt% carbon and other impurity elements whose total weight is less than 0.3wt%.

In the present invention, by adding a small amount of titanium element, a secondary phase of impurities such as carbon, manganese, iron and silicon can be formed inside the high-nickel alloy grains, so as to reduce the carbon content on the grain boundary and the overall impurity concentration in the alloy, thereby preventing the inter-graphitization and improve the corrosion resistance of the alloy.

In order to be able to understand the technical means of the present invention more clearly, so that it can be implemented according to the contents of the description, and in order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited together with the accompanying drawings , detailed below.

Description of drawings

Fig. 1 shows the manufacture method flowchart of corrosion-resistant high-nickel alloy of the present invention;

Fig. 2 shows that the titanium-containing high-nickel alloy of embodiment 2 presents a photo of an equiaxed grain structure under low-magnification electron microscope observation; and

Fig. 3 shows the secondary phase photo (a) and the EDX composition analysis result (b) of the titanium-containing high-nickel alloy of Example 2 observed under a high-magnification electron microscope.

detailed description

The invention provides a corrosion-resistant high-nickel alloy, which comprises 99.6-99.9wt% of nickel, 0.03-0.12wt% of titanium, 0.003-0.02wt% of carbon and the remaining total weight is less than 100wt%. 0.3wt% impurity elements, said impurity elements at least include manganese, iron, silicon, cobalt and copper.

In this embodiment, in order to increase the corrosion resistance of the alloy, preferably, the content of titanium is greater than that of silicon.

In addition, in order to further prevent porosity defects in high-nickel alloys, it is necessary to improve the degassing efficiency when smelting high-nickel alloys. Therefore, in this embodiment, in addition to the above-mentioned manganese, iron, silicon, cobalt and copper, the impurity elements may also include sulfur or zinc, and preferably, the content of sulfur or zinc should be less than that of titanium content to improve the degassing efficiency when smelting high-nickel alloys.

Fig. 1 shows the flow chart of the manufacturing method of corrosion-resistant high-nickel alloy of the present invention. Referring to step S11 in Fig. 1, alloy ingredients are provided, and the alloy ingredients are calculated based on the total weight of 100wt%, including 99.5-99.9wt% of nickel, 0.05-0.3wt% of titanium, 0.005-0.1wt% of carbon and The remaining impurity elements include at least manganese, iron, silicon, cobalt and copper. In this step, in order to increase the corrosion resistance of the alloy, preferably, the content of titanium is greater than that of silicon.

In addition, in order to improve the degassing efficiency during the subsequent smelting of high-nickel alloys and to further prevent the occurrence of pore defects in high-nickel alloys, the impurity elements may also include sulfur or Zinc, and preferably, the content of sulfur or zinc should be less than that of titanium, so as to improve the degassing efficiency when smelting high-nickel alloys.

Referring to step S12, smelting the alloy ingredients to produce a corrosion-resistant high-nickel alloy, the corrosion-resistant high-nickel alloy is calculated as 100wt% of its total weight, including 99.6-99.9wt% nickel, 0.03-0.12wt% % titanium, 0.003-0.02wt% carbon and other impurity elements whose total weight is less than 0.3wt%.

In this step, the smelting method can be selected from one of the following: fuel heating furnace smelting, non-vacuum electric furnace (Electric Arc Furnace, EAF) smelting, vacuum induction furnace (Vacuum Induction Melting, VIM) smelting and vacuum electric arc furnace (Vacuum Arc Melting, VAM) melting.

In addition, after the step S12, a step of refining the corrosion-resistant high-nickel alloy may be included to improve the uniformity of the composition and structure of the alloy. Preferably, the refining method can be selected from one of the following: Argon Oxygen Decarburization (AOD), Vacuum Oxygen Decarburization (VOD), electroslag remelting (electroslag remelting, ESR) and vacuum arc remelting (Vacuum arc remelting, VAR).

In this embodiment, the electroslag remelting refining method may include adding titanium-containing slag material for refining, so as to cope with the burning loss of titanium during electroslag remelting. Preferably, the titanium-containing slag contains 3-20% TiO ₂ (titanium dioxide), and the titanium-containing slag can optionally include CaF ₂ -CaO-MgO-Al ₂ O ₃ -SiO ₂ -TiO ₂ (calcium fluoride-calcium oxide-magnesia-alumina-silicon dioxide-titania) slag system.

Moreover, in order to ensure that the surface quality of the corrosion-resistant high-nickel alloy meets the requirements of subsequent processing applications, a surface treatment step may be included after the refining step. In this embodiment, the surface treatment step may include surface finishing procedures such as cutting, grinding and peeling.

In the present invention, by adding a small amount of titanium element, a secondary phase of impurities such as carbon, manganese, iron and silicon can be formed inside the high-nickel alloy grains, so as to reduce the carbon content on the grain boundary and the overall impurity concentration in the alloy, thereby preventing the inter-graphitization and improve the corrosion resistance of the alloy.

The present invention is described in detail with the following examples, but it does not mean that the present invention is limited to the content disclosed in these examples.

Example 1

According to the weighing and batching method in Table 2, the raw materials of each element are smelted to become high-nickel alloy blanks within the target composition range, and the blanks can be obtained by decarburization with argon blowing oxygen after smelting in an electric furnace. Then carry out the surface treatment step, depending on the surface condition of the casting blank, carry out surface finishing including cutting, grinding, peeling, etc., so as to ensure the surface quality of the casting blank before processing.

Table 2. Ingot composition of titanium-containing high-nickel alloy obtained by weighing ingredients

Example 2

According to the batching method in Table 3, the billet can be refined by electroslag remelting (ESR) after smelting in an electric furnace. Because titanium is prone to burning loss during electroslag remelting, titanium-containing slag can be added, and the above-mentioned The titanium-containing slag material selects the slag system containing CaF ₂ -CaO-MgO-Al ₂ O ₃ -SiO ₂ -TiO ₂ to ensure the titanium content in the alloy ingot. Usually, the refined alloy embryo has a uniform structure, no coarse inclusions, and good processing properties, so it is suitable for forming methods such as forging or rolling. Then carry out the surface treatment step, depending on the surface condition of the casting blank, carry out surface finishing including cutting, grinding, peeling, etc., so as to ensure the surface quality of the casting blank before processing.

Table 3. Ingot composition of titanium-containing high-nickel alloy obtained by electroslag remelting and refining with titanium-containing slag

Comparative example 1 of the present invention selects Ni 200 for use, and its composition is 99.5Ni-0.15Fe-0.1Mn-0.1Si-0.05C-0.03Co; And comparative example 2 selects Ni 201 for use, and its composition is 99.75Ni-0.08Fe-0.07Mn -0.01Si-0.02C-0.05Co.

Table 4 shows the immersion corrosion test results of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 in different solutions. In Table 4, the lower the corrosion rate or the less the immersion weight loss, the better the corrosion resistance of the alloy.

The results in Table 4 show that the corrosion rates of Comparative Example 1 and Comparative Example 2 are not much different, indicating that when the nickel content is higher than 99.5wt%, it is difficult to clearly judge the influence of the slight difference in nickel content on the corrosion resistance of high-nickel alloys. However, the corrosion rate of the high-nickel alloys in Examples 1 and 2 was not only significantly reduced after titanium was added, but also the immersion weight loss was also greatly reduced, which proves that the high-nickel alloys containing titanium do have excellent corrosion resistance.

Table 4. The immersion corrosion test results of embodiment 1, embodiment 2, comparative example 1 and comparative example 2 in different solutions

FIG. 2 shows a photo of the titanium-containing high-nickel alloy of Example 2 showing an equiaxed grain structure under low-magnification electron microscope observation. Fig. 3 shows the secondary phase photo (a) and the EDX composition analysis result (b) of the titanium-containing high-nickel alloy of Example 2 observed under a high-magnification electron microscope. Figure 2 and Figure 3 show the secondary phase of carbon oxides unique to titanium-containing high-nickel alloys. Such inclusions (interventions) take advantage of the high binding ability of titanium to carbon, oxygen and other elements, and these unfavorable corrosion resistance The elements (such as carbon, oxygen, manganese, iron, silicon, etc.) are concentrated in the secondary phase inside the grain to effectively reduce the impurity content in the substrate and its easily corroded grain boundaries, thereby achieving the purpose of improving corrosion resistance result.

In addition, comparing the titanium loss in Table 2 and Table 3, it can also be known that the use of titanium-containing slag in the electroslag remelting process in Example 2 can indeed reduce the burning loss of titanium during refining, and can reduce the loss of titanium due to heavy electroslag. The melting effect avoids the segregation of impurities, makes the distribution of the secondary phase more uniform, and then obtains the good corrosion resistance results shown in Table 4.

The corrosion-resistant high-nickel alloy of the present invention can be subsequently subjected to hot or cold processing such as forging, rolling, and wire drawing to form products such as plates, coils, rods, and wires, so as to facilitate various types of industrial applications. In addition, the corrosion-resistant high-nickel alloy of the present invention can also be applied to caustic alkali environments such as KOH and NaOH, and acid and alkali environments containing NH ₄ F, H ₂ SO ₄ , HCl, HF, NH ₄ , HNO ₃ or their mixtures.

The above-mentioned embodiments are only for illustrating the principles and functions of the present invention, but not for limiting the present invention. Therefore, those skilled in the art can modify and change the above-mentioned embodiments without departing from the spirit of the present invention.

Claims (16)

1. A kind of corrosion-resistant high-nickel alloy, described corrosion-resistant high-nickel alloy calculates with its gross weight as 100wt%, comprises the nickel of 99.6～99.9wt%, the titanium of 0.03～0.12wt%, the titanium of 0.003～0.02wt% Carbon and other impurity elements whose total weight is less than 0.3wt%, said impurity elements at least include manganese, iron, silicon, cobalt and copper. 2. corrosion-resistant high-nickel alloy according to claim 1, Wherein the content of titanium is greater than that of silicon. 3. corrosion-resistant high-nickel alloy according to claim 1, Wherein the content of copper is less than that of titanium. 4. corrosion-resistant high-nickel alloy according to claim 1, The impurity elements mentioned therein also include sulfur, and the content of sulfur is less than that of titanium. 5. corrosion-resistant high-nickel alloy according to claim 1, The impurity elements mentioned therein also include zinc, and the content of zinc is less than that of titanium. 6. A method for manufacturing a corrosion-resistant high-nickel alloy, comprising the following steps: (a) Provide alloy ingredients, the alloy ingredients are calculated based on the total weight of 100wt%, including 99.5-99.9wt% of nickel, 0.05-0.3wt% of titanium, 0.005-0.1wt% of carbon and other impurity elements , the impurity elements include at least manganese, iron, silicon, cobalt and copper; and (b) smelting alloy batching, to make corrosion-resistant high-nickel alloy, described corrosion-resistant high-nickel alloy calculates with its gross weight as 100wt%, comprises the nickel of 99.6～99.9wt%, the titanium of 0.03～0.12wt%, 0.003-0.02wt% carbon and other impurity elements whose total weight is less than 0.3wt%. 7. the manufacture method of corrosion-resistant high-nickel alloy according to claim 6, Wherein the content of titanium in the alloy batch of step (a) is greater than the content of silicon. 8. the manufacture method of corrosion-resistant high-nickel alloy according to claim 6, Wherein the content of copper in step (a) is less than that of titanium. 9. the manufacture method of corrosion-resistant high-nickel alloy according to claim 6, Wherein the impurity element in step (a) also includes sulfur, and the content of sulfur is less than that of titanium. 10. the manufacture method of corrosion-resistant high-nickel alloy according to claim 6, Wherein the impurity element in step (a) also includes zinc, and the content of zinc is less than that of titanium. 11. the manufacture method of corrosion-resistant high-nickel alloy according to claim 6, The smelting method in step (b) is selected from one of the following: fuel heating furnace smelting, non-vacuum electric furnace smelting, vacuum induction furnace smelting and vacuum electric arc furnace smelting. 12. the manufacture method of corrosion-resistant high-nickel alloy according to claim 6, Wherein after the step (b) also includes the step of refining the corrosion-resistant high-nickel alloy, and the refining method is selected from one of the following: argon oxygen blowing decarburization, vacuum oxygen blowing decarburization, electroslag remelting and vacuum Arc remelting. 13. the manufacture method of corrosion-resistant high-nickel alloy according to claim 12, Wherein, after the refining step, it also includes the step of surface treating the corrosion-resistant high-nickel alloy. 14. the manufacture method of corrosion-resistant high-nickel alloy according to claim 12, The electroslag remelting refining method described therein includes adding titanium-containing slag material for refining. 15. the manufacture method of corrosion-resistant high-nickel alloy according to claim 14, The titanium-containing slag material contains 3-20% TiO ₂ . 16. the manufacture method of corrosion-resistant high-nickel alloy according to claim 14, The titanium-containing slag material is selected from the slag system comprising CaF ₂ -CaO-MgO-Al ₂ O ₃ -SiO ₂ -TiO ₂ .