A nickel-chromium series precision resistance alloy pickling solution and pickling method

Abstract

The invention discloses a nickel-chromium precision resistance alloy pickling solution and a pickling method, wherein the pickling solution contains the following components in percentage by mass: 9% to 12% of hydrofluoric acid and 12% to 16% of nitric acid; the pickling method comprises: 1. washing the surface of the plate with flowing cold water; 2. placing the plate in the pickling solution for pickling treatment; 3. washing with flowing cold water; 4. washing with deionized water; 5. washing with ethanol solution. The pickling solution of the invention strictly controls its mass ratio to effectively and thoroughly remove the oxide scale generated by hot rolling on the surface of the nickel-chromium precision resistance alloy, and does not generate intergranular corrosion and pitting on the surface of the nickel-chromium precision resistance alloy substrate. The hydrogen content and oxygen content are effectively controlled, thereby ensuring the pickling effect, and the pickling process is simple, does not require heating, has low pickling cost, low risk factor, high pickling efficiency, and is suitable for popularization and application.

Description

Technical Field

[0001] The invention belongs to the technical field of metal surface treatment, and in particular relates to a nickel-chromium series precision resistance alloy pickling solution and a pickling method. Background Art

[0002] Nickel-chromium precision resistance alloy is a key component of foil strain gauge and plays a decisive role in the performance of resistance strain gauge. Nickel-chromium precision resistance alloy is a resistance alloy with nickel, chromium, copper and aluminum as the main components. Due to its excellent high tensile strength, high corrosion resistance and non-magnetic properties, it has broad application prospects in instrumentation and other fields. It can be used to make miniature high-resistance precision winding resistors, precision resistors, sliding wire resistors, etc. in instrumentation. The new generation of NiCr-based alloys is marked by the addition of appropriate Cu and Al, which not only increases the use temperature of NiCr-based alloys by about 100°C, but also significantly improves its high-temperature oxidation resistance, corrosion resistance and creep resistance. The processing of nickel-chromium precision resistance alloy foil is usually completed by hot rolling + cold rolling. After hot rolling, there is inevitably oxide scale on the surface. Pickling is the front process of cold rolling of the plate. The hot-rolled plate is continuously passed through the pickling tank and the oxide scale is removed with acid. Since nickel-chromium alloys contain 19% to 21% chromium, a layer of chromium oxide passivation film is easily formed in conventional acid solution to protect the surface oxide scale of the alloy from corrosion. At present, there is no specific pickling method for nickel-chromium precision resistance alloys that can effectively remove the oxide scale during hot rolling + cold rolling. Therefore, it is urgent to invent a method with low risk factor, simple operation process, and the ability to remove the surface oxide layer of the alloy and greatly improve the pickling efficiency. This is of great significance for the subsequent rolling processing of the alloy foil and ensuring the stability of the foil performance. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a pickling method for nickel-chromium precision resistance alloys in view of the deficiencies of the above-mentioned prior art. The pickling solution strictly controls its mass ratio to effectively and thoroughly remove the oxide scale generated by hot rolling on the surface of the nickel-chromium precision resistance alloy, and does not cause intergranular corrosion and pitting corrosion on the surface of the nickel-chromium precision resistance alloy substrate, thereby ensuring the pickling effect, and the pickling process is simple and the pickling efficiency is high, thus solving the problem of the lack of a dedicated pickling method for nickel-chromium precision resistance alloys in the prior art.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a pickling solution for nickel-chromium precision resistance alloy, characterized in that it contains the following components in percentage by mass: 9% to 12% of hydrofluoric acid and 12% to 16% of nitric acid.

[0005] The above-mentioned pickling solution for nickel-chromium precision resistance alloy is characterized in that the components of the pickling solution also include solvent water.

[0006] The above-mentioned pickling solution for nickel-chromium precision resistance alloy is characterized in that the pickling solution is prepared by a mass ratio of 30:30:40 of a hydrofluoric acid solution with a mass concentration of 40%, a nitric acid solution with a mass concentration of 40% and water, or a mass ratio of 30:40:30 of a hydrofluoric acid solution with a mass concentration of 40%, a nitric acid solution with a mass concentration of 40% and water. The present invention designs two pickling solutions with different composition ratios according to the characteristics of nickel-chromium precision resistance alloys, and utilizes the synergistic effect of the chemical properties of hydrofluoric acid and nitric acid to achieve efficient removal of oxide layers of different thicknesses on the surface of nickel-chromium precision resistance alloys, while minimizing damage to the alloy itself and maintaining its composition and performance stability.

[0007] At the same time, the present invention also discloses a method for pickling a nickel-chromium precision resistance alloy using the pickling solution as described above, characterized in that the method comprises the following steps:

[0008] Step 1: Use running cold water to clean the surface of the nickel-chromium precision resistance alloy plate;

[0009] Step 2: Place the nickel-chromium precision resistance alloy plate washed with running cold water in step 1 in a pickling solution for pickling for 20 to 40 minutes, until the black-gray oxide scale on the surface of the nickel-chromium precision resistance alloy plate is completely removed, presenting a silvery white luster;

[0010] Step 3: Clean the surface of the nickel-chromium precision resistance alloy plate after the pickling treatment in step 2 with running cold water;

[0011] Step 4: Clean the surface of the nickel-chromium precision resistor alloy plate after being cleaned with running cold water in step 3 with deionized water;

[0012] Step 5: Use ethanol solution to clean the surface of the nickel-chromium precision resistor alloy plate after being cleaned with deionized water in step 4.

[0013] The above method is characterized in that the nickel-chromium precision resistance alloy plate in step 1 contains the following components in mass percentage: Ni 69% to 85%, Cr 10% to 21%, Cu 1.0% to 6.0%, and Al 2.0% to 9.0%. When the mass percentage of Cr in the nickel-chromium precision resistance alloy plate is greater than 15%, the chromium oxide passivation film formed on its surface after hot rolling is thicker, and it is necessary to use a pickling solution prepared by a mass ratio of 30:40:30 of a hydrofluoric acid solution with a mass concentration of 40%, a nitric acid solution with a mass concentration of 40% and water; when the mass percentage of Cr in the nickel-chromium precision resistance alloy plate is 10% to 15%, the oxide layer on its surface after hot rolling is thinner. At this time, it is effective and relatively gentle to select a pickling solution prepared by a mass ratio of 30:30:40 of a hydrofluoric acid solution with a mass concentration of 40%, a nitric acid solution with a mass concentration of 40% and water.

[0014] The above method is characterized in that the temperature of the pickling solution during the pickling treatment in step 2 does not exceed 40° C. This temperature condition helps to maintain the chemical stability of the pickling solution, ensures that hydrofluoric acid and nitric acid can react with oxide impurities on the surface of the nickel-chromium precision resistance alloy in an expected manner, and makes the pickling process more stable and controllable.

[0015] The above method is characterized in that the temperature of the deionized water in step 4 is 20°C to 30°C, and the cleaning time is 3min to 4min. By controlling the temperature of the deionized water, it is possible to effectively avoid the thermal expansion of the nickel-chromium precision resistance alloy caused by high or low temperature, which may cause changes in the internal stress of the alloy and affect subsequent processing; and the cleaning time of 3min to 4min can most effectively ensure the cleaning quality and efficiency.

[0016] The above method is characterized in that, in step 5, after cleaning with the ethanol solution, a clean blowing device is used to quickly dry the surface of the nickel-chromium precision resistance alloy plate to keep the surface dry.

[0017] The above method is characterized in that the surface finish, hydrogen content and oxygen content of the dried nickel-chromium precision resistance alloy plate are detected.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The present invention adopts a pickling solution composed of hydrofluoric acid and nitric acid in a specific ratio, which effectively avoids excessive corrosion of the alloy caused by a single acid solution due to excessively high concentration or chemical property limitations, and synergistically utilizes the complementary advantages of hydrofluoric acid and nitric acid to achieve accurate and efficient cleaning, thereby ensuring the pickling effect.

[0020] 2. The nickel-chromium precision resistance alloy of the present invention contains 10% to 21% Cr, which will quickly form a passivation film under the strong oxidizing property of nitric acid to protect the surface of the alloy matrix from corrosion. Therefore, by strictly controlling the mass ratio of hydrofluoric acid, nitric acid and water in the pickling solution, the hydrogen ions (H + ) content is just enough to react with the oxide scale on the surface of the nickel-chromium precision resistance alloy after hot rolling, destroy the structure of the chromium oxide passivation film, effectively and thoroughly remove the oxide scale generated on the surface of the nickel-chromium precision resistance alloy by hot rolling, and prevent the rapid generation of a new passivation film by maintaining the redox potential, thereby ensuring effective pickling.

[0021] 3. The content of main elements Ni and Cr in nickel-chromium precision resistance alloy and the interaction between other elements determine the properties of the surface oxide scale after hot rolling and the degree of acid tolerance. Based on the composition of nickel-chromium precision resistance alloy, the present invention specifically designs two pickling solutions with different mass ratios. They are precisely matched with the composition of nickel-chromium precision resistance alloy in terms of the ability to dissolve oxide scale, the protection of alloy matrix, overcoming the passivation characteristics of chromium and pickling efficiency, so as to ensure the best pickling effect.

[0022] 4. The pickling process of the present invention is simple and convenient, the pickling cost is low, the risk factor is small, and the surface of the nickel-chromium precision resistance alloy plate after pickling is silvery white and bright without surface defects. Its hydrogen content and oxygen content are effectively controlled, and the H element content is less than 0.001% and the O element content is less than 0.01%, which is suitable for promotion and application.

[0023] 5. The pickling solution of the present invention has good pickling effect, simple pickling process, no need for heating, and a fast removal rate at room temperature, which greatly improves the pickling efficiency.

[0024] 6. The pickling solution and pickling method of the present invention break the shackles of the lack of corresponding pickling solution for nickel-chromium precision resistance alloy plates, have broad application prospects, and can also be extended to the removal of thick oxide scale on the surface of other high-precision resistance alloy materials.

[0025] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Ni after drying in Example 1 of the present invention 69 Cr 21 Low-magnification microstructure of Cu1Al9 precision resistance alloy plate.

[0027] Figure 2 Ni after drying in Example 2 of the present invention 80 Cr 10 Macrostructure of Cu6Al4 precision resistance alloy sheet.

[0028] Figure 3 Ni after drying in Example 3 of the present invention 85 Cr 10 Low-magnification microstructure of Cu3Al2 precision resistance alloy plate. DETAILED DESCRIPTION

[0029] Example 1

[0030] This embodiment includes the following steps:

[0031] Step 1: Use running cold water to clean Ni 69 Cr 21 The surface of Cu1Al9 precision resistance alloy plate; 69 Cr 21 Cu1Al9 precision resistance alloy sheet contains the following components in mass percentage: Ni69%, Cr 21%, Cu 1%, Al9%;

[0032] Step 2: Wash the Ni 69 Cr 21 The Cu1Al9 precision resistance alloy plate is placed in the pickling solution for pickling for 40 minutes. The temperature of the pickling solution does not exceed 40°C during the pickling process until the Ni 69 Cr 21 The surface of the Cu1Al9 precision resistance alloy plate has silvery white bright oxide scale; the pickling solution contains the following components in percentage by mass: 9% hydrofluoric acid and 16% nitric acid, and the pickling solution is prepared by a hydrofluoric acid solution with a mass concentration of 40%, a nitric acid solution with a mass concentration of 40% and water in a mass ratio of 30:40:30;

[0033] Step 3: Use running cold water to clean the Ni after pickling in step 2 69 Cr 21 The surface of Cu1Al9 precision resistance alloy sheet;

[0034] Step 4: Use deionized water to clean the Ni 69 Cr 21 The surface of Cu1Al9 precision resistance alloy plate, the deionized water temperature is 20℃~30℃, and the cleaning time is 3min;

[0035] Step 5: Use ethanol solution to clean the Ni 69 Cr 21 The surface of Cu1Al9 precision resistance alloy sheet;

[0036] Step 6: Use a clean blowing device to clean the Ni 69 Cr21 The surface of the Cu1Al9 precision resistance alloy sheet is blown dry quickly to keep the surface dry.

[0037] The Ni after drying in this embodiment 69 Cr 21 The surface turning samples of Cu1Al9 precision resistance alloy plates were taken to detect the hydrogen content and oxygen mass content. The results are shown in Table 1 below.

[0038] Table 1

[0039]

[0040] From Table 1, we can see that after pickling, Ni 69 Cr 21 The hydrogen content and oxygen content in each part of the Cu1Al9 precision resistance alloy plate are effectively controlled to meet the specified requirements.

[0041] Figure 1 Ni after drying in this embodiment 69 Cr 21 Low-power microstructure diagram of Cu1Al9 precision resistance alloy plate. Figure 1 It can be seen that the pickling solution and pickling method of this embodiment can effectively remove Ni 69 Cr 21 Surface oxide scale of Cu1Al9 nickel-chromium precision resistance alloy hot-rolled plate.

[0042] Example 2

[0043] This embodiment includes the following steps:

[0044] Step 1: Use running cold water to clean Ni 80 Cr 10 The surface of Cu6Al4 precision resistance alloy plate; 80 Cr 10 Cu6Al4 precision resistance alloy sheet contains the following components in mass percentage: Ni80%, Cr 10%, Cu 6%, Al4%;

[0045] Step 2: Wash the Ni 80 Cr 10 The Cu6Al4 precision resistance alloy plate is placed in the pickling solution for pickling for 20 minutes. The temperature of the pickling solution does not exceed 40°C during the pickling process until the Ni 80 Cr 10The surface of the Cu6Al4 precision resistance alloy plate has silvery white bright oxide scale; the pickling solution contains the following components in percentage by mass: 12% hydrofluoric acid and 12% nitric acid, and the pickling solution is prepared by a hydrofluoric acid solution with a mass concentration of 40%, a nitric acid solution with a mass concentration of 40% and water in a mass ratio of 30:30:40;

[0046] Step 3: Use running cold water to clean the Ni after pickling in step 2 80 Cr 10 The surface of Cu6Al4 precision resistance alloy sheet;

[0047] Step 4: Use deionized water to clean the Ni 80 Cr 10 The surface of Cu6Al4 precision resistance alloy plate, the deionized water temperature is 20℃~30℃, and the cleaning time is 4min;

[0048] Step 5: Use ethanol solution to clean the Ni 80 Cr 10 The surface of Cu6Al4 precision resistance alloy sheet;

[0049] Step 6: Use a clean blowing device to clean the Ni 80 Cr 10 The surface of the Cu6Al4 precision resistance alloy sheet is blown dry quickly to keep the surface dry.

[0050] The Ni after drying in this embodiment 80 Cr 10 The surface turning samples of Cu6Al4 precision resistance alloy plates were taken to detect the hydrogen content and oxygen mass content. The results are shown in Table 2 below.

[0051] Table 2

[0052]

[0053] From Table 2, we can see that after pickling, Ni 80 Cr 10 The hydrogen content and oxygen content in each part of the Cu6Al4 precision resistance alloy plate are effectively controlled to meet the specified requirements.

[0054] Figure 2 Ni after drying in this embodiment 80 Cr 10 Low-power microstructure diagram of Cu6Al4 precision resistance alloy plate. Figure 2 It can be seen that the pickling solution and pickling method of this embodiment can effectively remove Ni 80 Cr 10Surface oxide scale of Cu6Al4 nickel-chromium precision resistance alloy hot-rolled plate.

[0055] Example 3

[0056] This embodiment includes the following steps:

[0057] Step 1: Use running cold water to clean Ni 85 Cr 10 The surface of Cu3Al2 precision resistance alloy plate; 85 Cr 10 Cu3Al2 precision resistance alloy sheet contains the following components in mass percentage: Ni85%, Cr 10%, Cu 3%, Al2%;

[0058] Step 2: Wash the Ni 85 Cr 10 The Cu3Al2 precision resistance alloy plate is placed in the pickling solution for pickling for 30 minutes. The temperature of the pickling solution does not exceed 40°C during the pickling process until the Ni 85 Cr 10 The surface of the Cu3Al2 precision resistance alloy plate has a silvery white bright oxide scale; the pickling solution contains the following components in percentage by mass: 12% hydrofluoric acid and 12% nitric acid, and the pickling solution is prepared by a hydrofluoric acid solution with a mass concentration of 40%, a nitric acid solution with a mass concentration of 40% and water in a mass ratio of 30:30:40;

[0059] Step 3: Use running cold water to clean the Ni after pickling in step 2 85 Cr 10 The surface of Cu3Al2 precision resistance alloy sheet;

[0060] Step 4: Use deionized water to clean the Ni 85 Cr 10 The surface of Cu3Al2 precision resistance alloy plate, the deionized water temperature is 20℃~30℃, and the cleaning time is 3min;

[0061] Step 5: Use ethanol solution to clean the Ni 85 Cr 10 The surface of Cu3Al2 precision resistance alloy sheet;

[0062] Step 6: Use a clean blowing device to clean the Ni 85 Cr 10 The surface of the Cu3Al2 precision resistance alloy sheet is quickly blown dry to keep the surface dry.

[0063] The Ni after drying in this embodiment85 Cr 10 The surface turning samples of Cu3Al2 precision resistance alloy plates were taken to detect the hydrogen content and oxygen mass content. The results are shown in Table 3 below.

[0064] Table 3

[0065]

[0066] From Table 3, we can see that after pickling, Ni 85 Cr 10 The hydrogen content and oxygen content in each part of the Cu3Al2 precision resistance alloy plate are effectively controlled to meet the specified requirements.

[0067] Figure 3 Ni after drying in this embodiment 85 Cr 10 Low-power microstructure diagram of Cu3Al2 precision resistance alloy plate. Figure 3 It can be seen that the pickling solution and pickling method of this embodiment can effectively remove Ni 85 Cr 10 Surface oxide scale of hot-rolled Cu3Al2 nickel-chromium precision resistance alloy plate.

[0068] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A pickling solution for nickel-chromium precision resistance alloy, characterized in that: The invention comprises the following components in percentage by weight: 9% to 12% of hydrofluoric acid and 12% to 16% of nitric acid.

2. The pickling solution for nickel-chromium precision resistance alloy according to claim 1, characterized in that: The components of the pickling solution also include solvent water.

3. The pickling solution for nickel-chromium precision resistance alloy according to claim 1, characterized in that: The pickling solution is prepared by a hydrofluoric acid solution with a mass concentration of 40%, a nitric acid solution with a mass concentration of 40% and water in a mass ratio of 30:30:40, or by a hydrofluoric acid solution with a mass concentration of 40%, a nitric acid solution with a mass concentration of 40% and water in a mass ratio of 30:40:

30.

4. A method for pickling a nickel-chromium precision resistance alloy using the pickling solution as claimed in any one of claims 1 to 3, characterized in that: The method comprises the following steps: Step 1: Use running cold water to clean the surface of the nickel-chromium precision resistance alloy plate; Step 2: Place the nickel-chromium precision resistance alloy plate washed with running cold water in step 1 in a pickling solution for pickling for 20 to 40 minutes, until the black-gray oxide scale on the surface of the nickel-chromium precision resistance alloy plate is completely removed, presenting a silvery white luster; Step 3: Clean the surface of the nickel-chromium precision resistance alloy plate after the pickling treatment in step 2 with running cold water; Step 4: Clean the surface of the nickel-chromium precision resistor alloy plate after being cleaned with running cold water in step 3 with deionized water; Step 5: Use ethanol solution to clean the surface of the nickel-chromium precision resistor alloy plate after being cleaned with deionized water in step 4.

5. The method according to claim 4, characterized in that The nickel-chromium precision resistance alloy plate material in step 1 contains the following components in mass percentage: Ni 69% to 85%, Cr 10% to 21%, Cu 1.0% to 6.0%, and Al 2.0% to 9.0%.

6. The method according to claim 4, characterized in that During the pickling treatment in step 2, the temperature of the pickling solution does not exceed 40°C.

7. The method according to claim 4, characterized in that The temperature of the deionized water in step 4 is 20° C. to 30° C., and the cleaning time is 3 min to 4 min.

8. The method according to claim 4, characterized in that In step 5, after cleaning with the ethanol solution, a clean blowing device is used to quickly blow dry the surface of the nickel-chromium precision resistance alloy plate to keep the surface dry.

9. The method according to claim 8, characterized in that The surface finish, hydrogen content and oxygen content of the nickel-chromium precision resistance alloy plate after drying were tested.

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