A method for surface cleaning of superalloy turnings
By employing a two-step cleaning process that combines alkaline and oxidizing cleaning solutions, the problem of incomplete cleaning of high-temperature alloy scraps has been solved, achieving efficient removal of surface oil and processing layers to meet the requirements of remelting and smelting.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF METAL RESEARCH - CHINESE ACAD OF SCI
- Filing Date
- 2026-03-13
- Publication Date
- 2026-06-16
Smart Images
Figure CN122214869A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metal material recycling technology, and in particular to a method for surface cleaning treatment of high-temperature alloy scrap. Background Technology
[0002] High-temperature alloys, due to their excellent high-temperature strength and oxidation resistance, are widely used in key hot-end components in aerospace, gas turbines, petrochemicals, and nuclear power. Currently, the global annual consumption of high-temperature alloys is approximately 300,000 tons, with wrought high-temperature alloys accounting for about 70%. The yield of finished products is only 50%, with raw material losses mainly occurring in smelting, casting, hot working (forging), and cold working (machining) stages. Among these, waste materials (cutting chips) generated from the subsequent finishing of forgings account for the largest proportion and are also valuable secondary resources of nickel and cobalt metals for recycling.
[0003] The recycling method for high-temperature alloy cutting chips is pyrometallurgy, which involves mixing alloy waste with primary raw materials and then remelting them. Common methods include electron beam melting, vacuum induction melting, electroslag remelting, and vacuum arc melting. Because the waste contains a large amount of molten cutting fluid and impurities, rigorous cleaning is essential to remove these contaminants and prevent any impact on the purity and performance of the remelted high-temperature alloy.
[0004] Currently, alkaline reagents are commonly used to clean cutting fluid adhering to the surface of cutting materials. Saponification is used to break down the grease into glycerol and carboxylates. Glycerol has excellent water solubility, while carboxylates are anionic surfactants that promote emulsification, thus removing the oil stains. For example, the first related technology provides a method for treating scraped high-temperature alloy return materials, which involves sorting, crushing, and a two-step alkaline wash followed by citric acid neutralization, effectively removing non-metallic inclusions from the surface of the scrap and improving the utilization rate of the return material. The second related technology discloses a method for cleaning rare and precious metal turning materials, including sorting and impurity removal, spray rough washing, ultrasonic cleaning, bubbling rinsing, and drying, enabling the original smelting of rare and precious metals.
[0005] However, current chip cleaning technology faces at least two problems that urgently need to be addressed:
[0006] (1) High-temperature alloys are difficult to process, and the cutting fluid needs to take into account multiple functions such as lubrication, cooling and corrosion prevention. Alkaline cleaning fluid (with sodium hydroxide and sodium carbonate as the core) cannot deeply remove the coolant through saponification reaction, resulting in the residue of non-metallic impurity elements. Although the cleaning effect can be improved by supplementing with high-concentration surfactants and chelating agents / complexing agents, the cleaning fluid remains on the metal surface and some cleaning agent components have poor degradability, which can easily cause environmental pollution.
[0007] (2) The instantaneous high temperature during material processing causes the surface of the scrap to form a complex processing layer, mainly composed of oxides and nitrides. It is difficult to achieve efficient removal by alkaline cleaning solution. The scrap has low purity and excessive content of gaseous elements such as O, N, and S. It cannot be recycled as a return material through remelting and smelting. Existing cleaning processes rarely consider the structural characteristics of the processing layer and its efficient removal.
[0008] In summary, there is an urgent need for a new method for cleaning the surface of high-temperature alloy scrap to solve the technical problems of incomplete cleaning and easy contamination of high-temperature alloy scrap in existing technologies. Summary of the Invention
[0009] In view of this, the present invention provides a method for cleaning the surface of high-temperature alloy scrap, the main purpose of which is to solve the technical problems of incomplete cleaning of high-temperature alloy scrap and easy contamination in the prior art.
[0010] To achieve the above objectives, the present invention mainly provides the following technical solutions:
[0011] This invention provides a method for cleaning the surface of high-temperature alloy scrap, which includes the following steps:
[0012] Alkaline washing step: The high-temperature alloy scrap to be treated is cleaned with an alkaline cleaning solution to remove the oil layer covering the surface of the high-temperature alloy scrap; the high-temperature alloy scrap after alkaline washing is obtained; wherein, by mass percentage, the alkaline cleaning solution includes: 0.1~4 wt.% emulsifier, 2~6 wt.% alkaline additive, 0.2~1 wt.% flocculant, and the balance is water; wherein, the emulsifier includes ionic surfactants and nonionic surfactants;
[0013] Pickling step: The high-temperature alloy scrap after alkaline washing is cleaned with an oxidizing pickling solution to remove the surface processing layer on the high-temperature alloy scrap; after washing with water and drying, the high-temperature alloy scrap after surface cleaning treatment is obtained; wherein, the oxidizing pickling solution includes hydrohalic acid, oxidizing substances with hydroxyl bond structure and water.
[0014] Preferably, the high-temperature alloy chips to be processed are chips formed during machining.
[0015] Preferably, the surface of the high-temperature alloy scrap to be processed has a processing layer formed during the processing; an oil stain layer adheres to the surface of the processing layer; wherein the processing layer comprises oxides; preferably, the oxides comprise chromium oxide; preferably, the oil stain layer comprises cutting oil; more preferably, the cutting oil comprises coolant, organic rust inhibitor, bactericide, and extreme pressure additive.
[0016] Preferably, the high-temperature alloy scrap to be processed is deformed high-temperature alloy scrap.
[0017] Preferably, the ionic surfactant is selected from at least one of alkyl sulfate and alkyl sulfonate; more preferably, the ionic surfactant is selected from sodium dodecylbenzene sulfonate (SDBS) and / or sodium dodecyl sulfate (SDS).
[0018] Preferably, the nonionic surfactant is a nonionic surfactant with an HLB value between 8 and 18, and preferably at least one of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and alkyl glycoside; more preferably, the nonionic surfactant is one or more of octylphenol polyoxyethylene ether OP-10, fatty alcohol polyoxyethylene ether (AEO-9), and alkyl glycoside (APG-0810).
[0019] Preferably, the mass ratio of the nonionic surfactant to the ionic surfactant is 1:1 to 3:1.
[0020] Preferably, the alkaline additive includes sodium hydroxide and sodium carbonate; wherein, in the alkaline cleaning solution: the mass fraction of sodium hydroxide is 1~3% and the mass fraction of sodium carbonate is 1~3%.
[0021] Preferably, the flocculant is sodium silicate.
[0022] Preferably, in the alkaline washing step: the high-temperature alloy scrap to be treated is immersed in the alkaline cleaning solution for ultrasonic cleaning; preferably, the temperature of the ultrasonic cleaning treatment is below 60°C, preferably 25~50°C; the ultrasonic power is 300~600W, and the ultrasonic power density is 0.4~0.8W / cm³. 2 The ultrasonic cleaning process takes 30 to 90 minutes. Preferably, the ratio of the mass of the high-temperature alloy scrap to the volume of the alkaline cleaning solution is 1:1 to 1:5, in kg / L, and preferably 1:2.
[0023] Preferably, in the oxidizing pickling solution: the oxidizing substance having a hydroxyl bond structure is hydrogen peroxide; the hydrohalic acid is hydrochloric acid; preferably, the concentration of the hydrochloric acid is 2~4 mol / L, and the concentration of the hydrogen peroxide is 0.4~2.2 mol / L.
[0024] Preferably, in the pickling step: the high-temperature alloy scrap after alkaline washing is immersed in an oxidizing pickling solution for ultrasonic cleaning; preferably, the temperature of the ultrasonic cleaning is below 60°C, preferably 20~50°C, the ultrasonic power is 300~600W, and the ultrasonic power density is 0.4~0.8W / cm³. 2The ultrasonic cleaning time is 15~45min, preferably 30~45min.
[0025] Preferably, in the alkaline washing step: after the cleaning treatment, the high-temperature alloy scraps treated with the alkaline cleaning solution need to be rinsed with deionized water.
[0026] Preferably, in the pickling step, the water washing is performed by rinsing the high-temperature alloy scrap after cleaning with oxidizing pickling solution using deionized water.
[0027] Preferably, the oxygen content in the surface layer of the high-temperature alloy scrap after the surface cleaning treatment is ≤50ppm, the nitrogen content is ≤25ppm, and the sulfur content is less than 10ppm.
[0028] Compared with the prior art, the surface cleaning treatment method for high-temperature alloy scrap of the present invention has at least the following beneficial effects:
[0029] This invention provides a method for surface cleaning treatment of high-temperature alloy scrap, comprising the following steps: Alkaline washing step: using an alkaline cleaning solution to clean the high-temperature alloy scrap to remove the oil layer coating the surface of the scrap; obtaining alkaline-washed high-temperature alloy scrap; wherein, by mass percentage, the alkaline cleaning solution comprises: 0.1~4 wt.% emulsifier, 2~6 wt.% alkaline additive, 0.2~1 wt.% flocculant, and the balance being water; wherein, the emulsifier comprises ionic surfactants and nonionic surfactants; Acid washing step: using an oxidizing acid washing solution to clean the alkaline-washed high-temperature alloy scrap to remove the surface processing layer on the scrap; after washing with water and drying, obtaining surface-cleaned high-temperature alloy scrap; wherein, the oxidizing acid washing solution comprises hydrohalic acid (preferably hydrochloric acid), an oxidizing substance with a hydroxyl bond structure (preferably hydrogen peroxide), and water. The above scheme is explained as follows:
[0030] This invention addresses the contaminants and compositional characteristics of high-temperature alloy scrap surfaces (the surface of high-temperature alloy scrap has a machining layer formed by the instantaneous high temperature during processing, mainly composed of oxides such as chromium oxide, and the outer layer is generally coated with cutting oil, mainly coolant, organic rust inhibitors, bactericides, and extreme pressure additives, etc.). A two-step cleaning process was designed as described above. First, the alkaline cleaning solution is used to remove the oil layer coating the scrap surface. The alkaline cleaning solution designed in this invention combines nonionic and ionic surfactants to produce a synergistic cleaning effect. The nonionic surfactant mainly forms a hydration layer, reducing surface tension through steric hindrance, thus emulsifying and dispersing the oil. The ionic surfactant imparts a certain charge to the oil-in-water emulsion, preventing the washed-off oil droplets from re-aggregating. The synergistic combination of these two surfactants can deeply remove complex cutting fluids including organic rust inhibitors (alkylamines, amides), bactericides, and extreme pressure additives, and is not limited to treating single mineral or vegetable oils. Subsequently, an oxidizing pickling solution is used to remove the surface processing layer. This invention designs an acidic cleaning agent composed of hydrohalic acid (preferably hydrochloric acid) and an oxidizing substance with a hydroxyl bond structure (preferably hydrogen peroxide). The synergistic effect of halide ions (preferably chloride ions) and the oxidizing substance with a hydroxyl bond structure (hydrogen peroxide) triggers an imbalance in the "generation and repair" of defects within the oxide layer. Halogen ions (preferably chloride ions) first adsorb and catalyze lattice decomposition, generating oxygen vacancies and cation vacancies. The oxidizing substance with a hydroxyl bond structure (hydrogen peroxide) plays a crucial role: its high oxidation potential significantly accelerates the generation of cation vacancies. Simultaneously, as a strong electron absorber, it creates an electron surplus environment at the metal interface, strongly inhibiting the repair reaction of cation vacancies. This leads to the continuous aggregation and merging of cation vacancies at the interface into microscopic voids, ultimately undermining the structural integrity of the oxide layer from the inside, achieving rapid and thorough stripping.
[0031] It should be noted that in the alkaline washing step of the above-mentioned scheme of the present invention, the selection of a nonionic surfactant with a specific structure not only plays a role in emulsification and degreasing, but more importantly, it forms a temporary directional adsorption layer on the alloy surface. This adsorption layer plays a key role in the subsequent acid washing: ① Regulating wetting: It enables the hydrochloric acid-hydrogen peroxide mixture to uniformly wet the entire surface, avoiding local over-corrosion. ② Corrosion inhibition function: The oxygen atoms on the polyoxyethylene chains or sugar rings can temporarily coordinate with the active sites on the metal surface, slowing down the direct attack of acid on the substrate. ③ Promoting peeling: The adsorption layer is gradually destroyed during the acid washing process, and the interfacial micro-perturbation generated in this process helps the mechanical peeling of the oxide layer. Therefore, the selection of nonionic surfactant in the alkaline washing step directly affects the acid washing effect of the acid washing step. These two steps are a tightly coupled synergistic system, rather than a simple series connection. Therefore, the scheme of the present invention solves the problems of incomplete cleaning, heavy contamination, or damage to the substrate in the prior art.
[0032] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description
[0033] Figure 1 EPMA plots showing the morphology and elemental distribution of the cross-section of the high-temperature alloy sample; among them,
[0034] (a) Figure is an EPMA diagram of the cross-sectional morphology and elemental distribution of the high-temperature alloy sample after alkaline washing in Comparative Example 4; (b) Figure is an EPMA diagram of the cross-sectional morphology and elemental distribution of the high-temperature alloy scrap sample after surface cleaning treatment obtained in Comparative Example 4; (c) Figure is an EPMA diagram of the cross-sectional morphology and elemental distribution of the high-temperature alloy scrap sample after surface cleaning treatment obtained in Example 1.
[0035] Figure 2 Figure 1 shows the surface morphology and elemental distribution of the high-temperature alloy scrap sample after alkaline washing. (a) shows the surface morphology and elemental distribution of the free surface of the high-temperature alloy scrap sample after alkaline washing; (b) shows the surface morphology and elemental distribution of the contact surface of the high-temperature alloy scrap sample after alkaline washing.
[0036] Figure 3 Figure 1 shows the morphology and elemental distribution of high-temperature alloy scrap samples. (a) Figure 2 shows the morphology and elemental distribution of high-temperature alloy scrap samples after pickling for 15 min in Comparative Example 4; (b) Figure 3 shows the morphology and elemental distribution of high-temperature alloy scrap samples after pickling for 15 min in Example 1; (c) Figure 4 shows the morphology and elemental distribution of the contact surface of high-temperature alloy scrap samples after pickling for 30 min in Example 1; and (d) Figure 5 shows the morphology and elemental distribution of the free surface of high-temperature alloy scrap samples after pickling for 30 min in Example 1. Detailed Implementation
[0037] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description, in conjunction with preferred embodiments, provides a detailed explanation of the specific implementation methods, structures, features, and effects according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.
[0038] To address the problems existing in current technologies, and in order to improve the utilization rate of high-temperature alloy cutting waste, reduce the pressure of deep removal of gaseous impurities during subsequent remelting and smelting processes, and obtain remelted high-temperature alloys whose composition and properties meet regeneration standards, this invention develops a surface cleaning treatment method for high-temperature alloy scrap. The main solution of this invention is as follows:
[0039] This invention provides a method for cleaning the surface of high-temperature alloy scrap, which mainly includes the following steps:
[0040] Alkaline washing step: The high-temperature alloy scrap to be treated is cleaned with an alkaline cleaning solution to remove the oil layer covering the surface of the high-temperature alloy scrap; the high-temperature alloy scrap after alkaline washing is obtained; wherein, by mass percentage, the alkaline cleaning solution includes: 0.1~4 wt.% emulsifier, 2~6 wt.% alkaline additive, 0.2~1 wt.% flocculant, and the balance is water; wherein, the emulsifier includes ionic surfactants and nonionic surfactants;
[0041] The surface of the high-temperature alloy chips to be processed has a machining layer formed by the instantaneous high temperature during machining, mainly composed of oxides, such as chromium oxide. The outer layer is generally also covered with cutting oil, mainly a composite cutting oil containing coolant, organic rust inhibitors, bactericides, and extreme pressure additives. These high-temperature alloy chips are mainly formed during the machining of deformed high-temperature alloys, belonging to the machining waste generated during turning and milling processes.
[0042] The emulsifier comprises ionic and nonionic surfactants. The ionic surfactant is selected from at least one of alkyl sulfates and alkyl sulfonates. More preferably, the ionic surfactant is selected from sodium dodecylbenzene sulfonate (SDBS) and / or sodium dodecyl sulfate (SDS). The nonionic surfactant is selected from nonionic surfactants with an HLB value between 8 and 18, preferably from at least one of alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, and alkyl glycosides. More preferably, the nonionic surfactant is selected from one or more of octylphenol polyoxyethylene ether OP-10, fatty alcohol polyoxyethylene ether (AEO-9), and alkyl glycoside (APG-0810). The mass ratio of the nonionic surfactant to the ionic surfactant is 1:1 to 3:1.
[0043] The alkaline additives include sodium hydroxide and sodium carbonate; wherein, in the alkaline cleaning solution, the mass fraction of sodium hydroxide is 1-3% and the mass fraction of sodium carbonate is 1-3%.
[0044] Sodium silicate is selected as the flocculant.
[0045] In this step, the high-temperature alloy scrap to be treated is immersed in the alkaline cleaning solution for ultrasonic cleaning; preferably, the ultrasonic cleaning temperature is below 60°C, more preferably 25~50°C, the ultrasonic power is 300~600W, and the ultrasonic power density is 0.4~0.8W / cm³. 2 The ultrasonic cleaning process takes 30 to 90 minutes.
[0046] It should be noted that during alkaline washing, the temperature should not exceed the cloud point or decomposition temperature of the emulsifier to avoid dehydration and shrinkage of organic chains due to reduced emulsifier solubility, thus ensuring optimal emulsification. Simultaneously, the ultrasonic power parameters must be selected to suit the dimensions of the cleaning tank, ensuring the cleaning power density is controlled within 0.4~0.8 W / cm³. 2 Ideally, the ultrasonic power range should be determined by whether the cleaning solution forms a stable emulsion, exhibiting neither stratification nor excessive foaming. Insufficient ultrasonic power leads to sludge buildup at the bottom of the debris, resulting in poor emulsification by the emulsifier and low degreasing efficiency of the alkaline cleaning solution. Conversely, excessively high ultrasonic power causes rapid heat accumulation and a rapid temperature rise, significantly impacting nonionic surfactants and easily leading to precipitation.
[0047] The nonionic surfactant is a nonionic surfactant with an HLB value (hydrophilic-lipophilic balance value) between 8 and 18, preferably at least one of alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, and alkyl glycosides. Each of these surfactants contains a hydrophobic group (alkyl chain or alkylphenol) and a hydrophilic group (polyoxyethylene chain or sugar ring) connected by an ether bond (or glycosidic bond). The hydrophilic group contains multiple oxygen atoms (ether oxygen atoms or hydroxyl groups) capable of forming hydrogen bonds with water. This forms a hydration layer in the aqueous solution, reducing surface tension through steric hindrance and emulsifying and dispersing oil stains. The nonionic surfactant can be compounded with ionic surfactants to produce a synergistic effect, further improving the cleaning effect. Ionic surfactants are preferably alkyl sulfates or alkyl sulfonates, whose main function is to impart a certain charge characteristic to the oil-in-water emulsion, preventing the washed-off oil droplets from re-aggregating. By using two types of surfactants in synergy to balance emulsification, it can deeply remove complex cutting fluids containing organic rust inhibitors (alkylamines, amides), bactericides, and extreme pressure additives, rather than just treating single mineral or vegetable oils.
[0048] Pickling step: The high-temperature alloy scrap after alkaline washing is cleaned with an oxidizing pickling solution to remove the surface processing layer on the high-temperature alloy scrap; after washing with water and drying, the high-temperature alloy scrap after surface cleaning treatment is obtained.
[0049] The oxidizing pickling solution includes hydrohalic acid (selected here as an acid with complexing ability and small anionic radius), an oxidizing substance with a hydroxyl bond structure (which can be excited to form hydroxyl radicals under ultrasonic action), and water; wherein the concentration of hydrohalic acid is 2~4 mol / L, and the concentration of the oxidizing substance with a hydroxyl bond structure is 0.4~2.2 mol / L.
[0050] Here, for the aforementioned oxidizing pickling solution, the optimal compounding scheme is hydrochloric acid, hydrogen peroxide, and water. Synergistic regulation of Cl is required. - The ratio of hydrochloric acid to hydrogen peroxide (concentration of hydrochloric acid is 2~4 mol / L, concentration of hydrogen peroxide is 0.4~2.2 mol / L), when the Cl in the pickling solution... - At low concentrations, surface oxides dissolve slowly, and the alloy matrix becomes passivated. After pickling, the O and N contents remain at a high level. When the H2O2 in the pickling solution reaches a critical value, the surface oxides on the alloy surface dissolve rapidly and form a salt film mainly composed of matrix elements such as Ni and Cr. This product layer has low density. After pickling, rinsing again can deeply remove elements such as O and N, and the gaseous impurities meet the requirements for remelting. However, when the H2O2 content continues to increase, although the surface oxides can also dissolve quickly, the matrix dissolution state is close to polishing. The surface is over-pickled, forming a large number of pitting corrosions. At the same time, the local alkalinity is enhanced, and the salt film is converted into hydroxides. After rinsing, the O content remains at a high level, and the metal loss rate is high.
[0051] In this step, the high-temperature alloy scrap after alkaline washing is immersed in an oxidizing acid pickling solution for ultrasonic cleaning. The ultrasonic cleaning temperature is below 60°C, preferably 20-50°C, the ultrasonic power is 300-600W, and the ultrasonic power density is 0.4-0.8W / cm³. 2 The ultrasonic cleaning time is 15-45 minutes, preferably 30-45 minutes. It should be noted that the cleaning temperature and frequency also need to be controlled in tandem to avoid the rapid decomposition of hydrogen peroxide into water and oxygen due to heat accumulation. Simultaneously, the ultrasonic cavitation effect induces the breakage of hydroxyl bonds in the solution components, forming hydroxyl radicals, increasing the solution potential, and promoting the electrochemical dissolution of oxides such as Cr2O3 on the surface of the high-temperature alloy. If the pickling time is too long, although the processed layer will be removed, a large amount of the metal substrate will also begin to dissolve, significantly reducing the metal yield. Therefore, the pickling time should not exceed 45 minutes.
[0052] It should be noted that the ultrasonic treatment in the above steps is to make it easier to drag the oil off the metal surface; while the ultrasonic treatment in the acid washing process is to stimulate the hydride bond to break and form hydroxyl radicals.
[0053] Preferably, the surface cleaning treatment method for high-temperature alloy scrap provided in this embodiment of the invention includes a pretreatment step before the alkaline washing step: crushing and screening the high-temperature alloy scrap to uniformly process the size to -8.00mm to +3.35mm.
[0054] In the high-temperature alloy scrap obtained after surface cleaning treatment according to the above-described scheme of the present invention, both the contact surface and the free surface have a metallic luster and no significant difference in surface finish. The O, N, and S contents in the surface layer are comparable to those in the matrix, at 30-50 ppm, 10-25 ppm, and <10 ppm, respectively. Here, "contact surface" refers to the surface of the high-temperature alloy scrap that contacts the cutting tool during machining; this surface is relatively rough and has a relatively large oxide layer. "Free surface" refers to the other surfaces of the high-temperature alloy scrap besides the contact surface; these surfaces have a smaller oxide layer.
[0055] The present invention will be further illustrated below with specific embodiments:
[0056] Example 1
[0057] This embodiment involves surface cleaning treatment of GH4738 wrought superalloy scrap. The scrap surface has a processing layer and an oil layer. On the scrap surface, the C content can reach 0.25%; the O, N, and S contents are 420ppm, 83ppm, and 36ppm, respectively. The contents of these elements are all much higher than the corresponding element contents in the GH4738 wrought superalloy matrix, so it cannot be used as a relatively pure return material for remelting and reuse.
[0058] The surface cleaning treatment method provided in this embodiment includes the following steps:
[0059] Pre-treatment steps: The GH4738 deformed high-temperature alloy scrap is crushed and screened to uniformly process the size to -8.00mm to +3.35mm, thus obtaining the GH4738 deformed high-temperature alloy scrap to be processed.
[0060] Alkaline cleaning step: Prepare an alkaline cleaning solution, which, by mass percentage, comprises: 1 wt.% octylphenol polyoxyethylene ether (OP-10), 1 wt.% sodium dodecylbenzene sulfonate (SDBS), 1.5 wt.% sodium hydroxide, 3 wt.% sodium carbonate, 0.5 wt.% sodium silicate, and the balance being deionized water. Immerse the GH4738 deformed high-temperature alloy scrap to be treated in the alkaline cleaning solution and perform ultrasonic cleaning to obtain alkaline-treated high-temperature alloy scrap. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the ultrasonic power density is 0.8 W / cm³. 2The ultrasonic cleaning process was performed at a temperature of 40℃ for 60 minutes. The ratio of the mass of the GH4738 deformed high-temperature alloy scrap to the volume of the alkaline cleaning solution was 1:3 kg / L. The resulting high-temperature alloy scrap contained 0.047% C, 53 ppm O, 44 ppm N, and 15 ppm S.
[0061] Pickling Steps: Prepare an oxidizing pickling solution (including hydrochloric acid, hydrogen peroxide, and water), with an HCl concentration of 3 mol / L and an H₂O₂ concentration of 1.3 mol / L. Immerse the alkaline-washed high-temperature alloy scrap in the oxidizing pickling solution for ultrasonic cleaning. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the cleaning power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 30 minutes. After pickling, the material was rinsed twice with deionized water and dried to obtain high-temperature alloy scrap with a cleaned surface.
[0062] In the surface layer of the GH4738 wrought superalloy scrap obtained after surface cleaning treatment in this embodiment, the contents of C, O, N and S are 0.047%, 31ppm, 24ppm and 9ppm, respectively; the C content is consistent with the GH4738 wrought superalloy matrix, and the content of gaseous impurity elements meets the requirements of remelting smelting standards.
[0063] Example 2
[0064] This embodiment involves surface cleaning treatment of GH4738 wrought superalloy scrap. The scrap surface has a processing layer and an oil layer. On the scrap surface, the C content can reach 0.25%; the O, N, and S contents are 420ppm, 83ppm, and 36ppm, respectively. The contents of these elements are all much higher than the corresponding element contents in the GH4738 wrought superalloy matrix, so it cannot be used as a relatively pure return material for remelting and reuse.
[0065] The surface cleaning treatment method provided in this embodiment includes the following steps:
[0066] Pre-treatment steps: The GH4738 deformed high-temperature alloy scrap is crushed and screened to uniformly process the size to -8.00mm to +3.35mm, thus obtaining the GH4738 deformed high-temperature alloy scrap to be processed.
[0067] Alkaline cleaning step: Prepare an alkaline cleaning solution, which, by mass percentage, comprises: 0.9 wt.% fatty alcohol polyoxyethylene ether (AEO-9), 1 wt.% sodium dodecylbenzene sulfonate (SDBS), 1.5 wt.% sodium hydroxide, 3 wt.% sodium carbonate, 0.5 wt.% sodium silicate, and the balance being deionized water. Immerse the GH4738 deformed high-temperature alloy scrap to be treated in the alkaline cleaning solution and perform ultrasonic cleaning to obtain alkaline-treated high-temperature alloy scrap. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the ultrasonic power density is 0.8 W / cm³. 2 The ultrasonic cleaning temperature was 40℃, and the ultrasonic cleaning time was 60 minutes. The mass ratio of the GH4738 deformed high-temperature alloy chips to the volume of the alkaline cleaning solution was 1:3 kg / L. The C, O, N, and S content in the alkaline-treated high-temperature alloy chips was 0.047%, 58 ppm, 48 ppm, and 13 ppm, respectively. The deviation of the C, O, N, and S removal rates in each sample group of alkaline-treated high-temperature alloy chips was controlled within 5%. (It should be noted that alkaline cleaning only removes cutting oil and has a poor effect on oxide layer removal. Since the oxide layer thickness varies, the ONS value in each sample group after alkaline cleaning may differ. However, this does not mean that the cleaning was ineffective; a deviation within 5% is considered a relatively ideal alkaline cleaning effect.)
[0068] Pickling Steps: Prepare an oxidizing pickling solution (including hydrochloric acid, hydrogen peroxide, and water), with an HCl concentration of 3 mol / L and an H₂O₂ concentration of 2 mol / L. Immerse the alkaline-washed high-temperature alloy scrap in the oxidizing pickling solution for ultrasonic cleaning. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the cleaning power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 30 minutes. After pickling, the material was rinsed twice with deionized water and dried to obtain high-temperature alloy scrap with a cleaned surface.
[0069] In the surface layer of the GH4738 wrought superalloy scrap obtained after surface cleaning treatment in this embodiment, the contents of C, O, N and S are 0.047%, 35ppm, 21ppm and 10ppm, respectively. Among them, the C content is consistent with the GH4738 wrought superalloy matrix, and the content of gaseous impurity elements meets the requirements of remelting smelting standards.
[0070] Example 3
[0071] This embodiment involves surface cleaning treatment of GH4738 wrought superalloy scrap. The scrap surface has a processing layer and an oil layer. On the scrap surface, the C content can reach 0.25%; the O, N, and S contents are 420ppm, 83ppm, and 36ppm, respectively. The contents of these elements are all much higher than the corresponding element contents in the GH4738 wrought superalloy matrix, so it cannot be used as a relatively pure return material for remelting and reuse.
[0072] The surface cleaning treatment method provided in this embodiment includes the following steps:
[0073] Pre-treatment steps: The GH4738 deformed high-temperature alloy scrap is crushed and screened to uniformly process the size to -8.00mm to +3.35mm, thus obtaining the GH4738 deformed high-temperature alloy scrap to be processed.
[0074] Alkaline cleaning step: Prepare an alkaline cleaning solution, which, by mass percentage, comprises: 0.6 wt.% alkyl glycoside (APG-0810), 0.83 wt.% sodium dodecyl sulfate (SDS), 1.5 wt.% sodium hydroxide, 3 wt.% sodium carbonate, 0.5 wt.% sodium silicate, with the balance being deionized water. Immerse the GH4738 deformed high-temperature alloy scrap to be treated in the alkaline cleaning solution and perform ultrasonic cleaning to obtain alkaline-treated high-temperature alloy scrap. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the ultrasonic power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was conducted at 40℃ for 90 minutes. The mass ratio of the GH4738 deformed high-temperature alloy scrap to the volume of the alkaline cleaning solution was 1:3 kg / L. After alkaline cleaning, the C, O, N, and S content in the high-temperature alloy scrap was 0.047%, 64 ppm, 52 ppm, and 16 ppm, respectively. The deviation in the removal rates of C, O, N, and S after alkaline cleaning was controlled within 5%, and the alkaline cleaning wastewater exhibited good biodegradability.
[0075] Pickling Steps: Prepare an oxidizing pickling solution with HCl concentration of 2.5 mol / L and H₂O₂ concentration of 1.6 mol / L. Immerse the alkaline-washed high-temperature alloy scrap in the oxidizing pickling solution for ultrasonic cleaning. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the cleaning power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 30 minutes. After pickling, the material was rinsed twice with deionized water and dried to obtain high-temperature alloy scrap with a cleaned surface.
[0076] In this embodiment, the surface layer of the GH4738 wrought superalloy scrap after surface cleaning treatment contains 0.047% C, 26 ppm O, 19 ppm N, and 11 ppm S, respectively. The C content is consistent with the GH4738 wrought superalloy matrix, and the content of gaseous impurity elements meets the remelting and smelting standards.
[0077] Comparative Example 1
[0078] Comparative Example 1: GH4738 wrought superalloy scrap was subjected to surface cleaning treatment. The scrap surface had a processing layer and an oil layer. On the scrap surface, the C content reached 0.25%; the O, N, and S contents were 420 ppm, 83 ppm, and 36 ppm, respectively. The contents of these elements were all much higher than the corresponding element contents in the GH4738 wrought superalloy matrix, and therefore it could not be used as a relatively pure return material for remelting and reuse.
[0079] The surface cleaning treatment of Comparative Example 1 includes the following steps:
[0080] Pre-treatment steps: The GH4738 deformed high-temperature alloy scrap is crushed and screened to uniformly process the size to -8.00mm to +3.35mm, thus obtaining the GH4738 deformed high-temperature alloy scrap to be processed.
[0081] Alkaline cleaning step: Prepare an alkaline cleaning solution, which, by mass percentage, comprises: 2 wt.% sodium dodecylbenzenesulfonate (SDBS), 1.5 wt.% sodium hydroxide, 3 wt.% sodium carbonate, 0.5 wt.% sodium silicate, and the balance being deionized water. Immerse the GH4738 deformed high-temperature alloy scrap to be treated in the alkaline cleaning solution and perform ultrasonic cleaning to obtain alkaline-treated high-temperature alloy scrap. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the ultrasonic power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was performed at a temperature of 40℃ for 60 minutes. The mass ratio of the GH4738 deformed high-temperature alloy scrap to the volume of the alkaline cleaning solution was 1:3 kg / L. After alkaline cleaning, the C, O, N, and S content in the scrap was 0.056%, 162 ppm, 71 ppm, and 13 ppm, respectively, indicating a decrease in oil removal rate.
[0082] Pickling Steps: Prepare an oxidizing pickling solution with HCl concentration of 3 mol / L and H2O2 concentration of 1.3 mol / L. Immerse the alkaline-washed high-temperature alloy scrap in the oxidizing pickling solution for ultrasonic cleaning. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the cleaning power density is 0.8 W / cm³. 2The ultrasonic cleaning process was carried out at a temperature of 40℃ for 30 minutes. After pickling, the material was rinsed twice with deionized water and dried to obtain high-temperature alloy scrap with a cleaned surface.
[0083] In the surface layer of the GH4738 deformed high-temperature alloy scrap after surface cleaning treatment obtained in Comparative Example 1, the contents of C, O, N and S were 0.051%, 48ppm, 50ppm and 12ppm, respectively.
[0084] In Comparative Example 1, because no nonionic surfactant was added to the alkaline cleaning solution, the emulsification and dispersion effect during alkaline washing was poor. Furthermore, due to the complex composition of the cutting oil, some components that were difficult to undergo saponification could not be removed from the chip surface, resulting in a poor cleaning effect. The removal of gaseous elements during the acid washing stage was also somewhat limited, and the surface cleanliness of the chips was not as good as in the example.
[0085] Comparative Example 2
[0086] Comparative Example 2 involved surface cleaning treatment of GH4738 wrought superalloy scrap. The scrap surface had a processing layer and an oil layer. On the scrap surface, the C content reached 0.25%; the O, N, and S contents were 420 ppm, 83 ppm, and 36 ppm, respectively. The contents of these elements were all much higher than the corresponding element contents in the GH4738 wrought superalloy matrix, and therefore it could not be used as a relatively pure return material for remelting and reuse.
[0087] The surface cleaning treatment of Comparative Example 1 includes the following steps:
[0088] Pre-treatment steps: The GH4738 deformed high-temperature alloy scrap is crushed and screened to uniformly process the size to -8.00mm to +3.35mm, thus obtaining the GH4738 deformed high-temperature alloy scrap to be processed.
[0089] Alkaline cleaning step: Prepare an alkaline cleaning solution, which, by mass percentage, comprises: 2 wt.% octylphenol polyoxyethylene ether (OP-10), 1.5 wt.% sodium hydroxide, 3 wt.% sodium carbonate, 0.5 wt.% sodium silicate, and the balance being deionized water. Immerse the GH4738 deformed high-temperature alloy scrap to be treated in the alkaline cleaning solution and perform ultrasonic cleaning to obtain alkaline-treated high-temperature alloy scrap. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the ultrasonic power density is 0.8 W / cm³. 2The ultrasonic cleaning process was performed at 40°C for 60 minutes. The mass ratio of the GH4738 deformed high-temperature alloy scrap to the volume of the alkaline cleaning solution was 1:3 kg / L. After alkaline cleaning, the C, O, N, and S content in the scrap was 0.047%, 258 ppm, 77 ppm, and 13 ppm, respectively. The O content was significantly higher than in the previous example, indicating a decreased oil removal rate.
[0090] Pickling Steps: Prepare an oxidizing pickling solution with HCl concentration of 3 mol / L and H2O2 concentration of 1.3 mol / L. Immerse the alkaline-washed high-temperature alloy scrap in the oxidizing pickling solution for ultrasonic cleaning. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the cleaning power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 30 minutes. After pickling, the material was rinsed twice with deionized water and dried to obtain high-temperature alloy scrap with a cleaned surface.
[0091] In the surface layer of the GH4738 deformed high-temperature alloy scrap obtained after surface cleaning treatment in Comparative Example 2, the contents of C, O, N and S were 0.051%, 66ppm, 48ppm and 12ppm, respectively.
[0092] In Comparative Example 2, due to the absence of ionic surfactants, the emulsification and dispersion during alkaline washing were poor. Furthermore, because the cutting oil composition was complex, some components that were difficult to undergo saponification could not be removed from the chip surface, resulting in poor cleaning performance. The removal of gaseous elements during the acid washing stage was also somewhat limited, and the surface cleanliness of the chips was not as good as in the example.
[0093] Comparative Example 3
[0094] Comparative Example 3 involved surface cleaning treatment of GH4738 wrought superalloy scrap. The scrap surface had a processing layer and an oil layer. On the scrap surface, the C content reached 0.25%; the O, N, and S contents were 420 ppm, 83 ppm, and 36 ppm, respectively. The contents of these elements were all much higher than the corresponding element contents in the GH4738 wrought superalloy matrix, and therefore it could not be used as a relatively pure return material for remelting and reuse.
[0095] The surface cleaning treatment of Comparative Example 3 includes the following steps:
[0096] Pre-treatment steps: The GH4738 deformed high-temperature alloy scrap is crushed and screened to uniformly process the size to -8.00mm to +3.35mm, thus obtaining the GH4738 deformed high-temperature alloy scrap to be processed.
[0097] Alkaline cleaning step: Prepare an alkaline cleaning solution, which, by mass percentage, comprises: 1 wt.% octylphenol polyoxyethylene ether (OP-10), 1 wt.% sodium dodecylbenzene sulfonate (SDBS), 1.5 wt.% sodium hydroxide, 3 wt.% sodium carbonate, 0.5 wt.% sodium silicate, and the balance being deionized water. Immerse the GH4738 deformed high-temperature alloy scrap to be treated in the alkaline cleaning solution and perform ultrasonic cleaning to obtain alkaline-treated high-temperature alloy scrap. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the ultrasonic power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 60 minutes. The ratio of the mass of the GH4738 deformed high-temperature alloy scrap to the volume of the alkaline cleaning solution was 1:3 kg / L.
[0098] Pickling Steps: Prepare an oxidizing pickling solution with HCl concentration of 3 mol / L and H2O2 concentration of 4.2 mol / L. Immerse the alkaline-washed high-temperature alloy scrap into the oxidizing pickling solution for ultrasonic cleaning. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the cleaning power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 30 minutes. After pickling, the material was rinsed twice with deionized water and dried to obtain high-temperature alloy scrap with a cleaned surface.
[0099] In the surface layer of the GH4738 deformed high-temperature alloy scrap after surface cleaning treatment obtained in Comparative Example 3, the contents of C, O, N and S were 0.047%, 46ppm, 34ppm and 12ppm, respectively. Among them, there were more unwashed pickling products remaining on the surface, and the O content was significantly higher than that in the example.
[0100] Because the hydrogen peroxide concentration in the oxidizing pickling solution used in Comparative Example 3 was too high, the dissolution state of the high-temperature alloy scrap matrix was almost in the polishing state. The pickling was excessive, resulting in a large number of pitting corrosions. At the same time, the local alkalinity was enhanced, the salt film was converted into hydroxides, and the O element content after rinsing remained at a high level, resulting in a high metal loss rate.
[0101] Comparative Example 4
[0102] Comparative Example 4 involved surface cleaning treatment of GH4738 wrought superalloy scrap. The scrap surface had a processing layer and an oil layer. On the scrap surface, the C content reached 0.25%; the O, N, and S contents were 420 ppm, 83 ppm, and 36 ppm, respectively. The contents of these elements were all much higher than the corresponding element contents in the GH4738 wrought superalloy matrix, and therefore it could not be used as a relatively pure return material for remelting and reuse.
[0103] The surface cleaning treatment method provided in Comparative Example 4 includes the following steps:
[0104] Pre-treatment steps: The GH4738 deformed high-temperature alloy scrap is crushed and screened to uniformly process the size to -8.00mm to +3.35mm, thus obtaining the GH4738 deformed high-temperature alloy scrap to be processed.
[0105] Alkaline cleaning step: Prepare an alkaline cleaning solution, which, by mass percentage, comprises: 1 wt.% octylphenol polyoxyethylene ether (OP-10), 1 wt.% sodium dodecylbenzene sulfonate (SDBS), 1.5 wt.% sodium hydroxide, 3 wt.% sodium carbonate, 0.5 wt.% sodium silicate, and the balance being deionized water. Immerse the GH4738 deformed high-temperature alloy scrap to be treated in the alkaline cleaning solution and perform ultrasonic cleaning to obtain alkaline-treated high-temperature alloy scrap. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the ultrasonic power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 60 minutes. The ratio of the mass of the GH4738 deformed high-temperature alloy scrap to the volume of the alkaline cleaning solution was 1:3 kg / L.
[0106] Pickling step: Prepare a 3 mol / L HCl solution (free of hydrogen peroxide). Immerse the alkaline-washed high-temperature alloy scrap in the oxidizing pickling solution for ultrasonic cleaning. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the cleaning power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 30 minutes. After pickling, the material was rinsed twice with deionized water and dried to obtain high-temperature alloy scrap with a cleaned surface.
[0107] In the surface layer of the GH4738 deformed high-temperature alloy scrap after surface cleaning treatment obtained in Comparative Example 4, the contents of C, O, N and S were 0.047%, 55ppm, 36ppm and 12ppm, respectively. Among them, there were more unwashed pickling products remaining on the surface, and the contents of O and N were significantly higher than those in the example.
[0108] Since hydrogen peroxide was not used in the pickling solution used in Comparative Example 4, the oxidation potential of the acidic cleaning solution was low, the formation rate of cation vacancies was slow, and the processing oxide layer peeling efficiency remained at a low level. Therefore, after pickling for 30 minutes, the oxide layer was not completely peeled off, and the O and N content in the sample remained at a high level, making it unsuitable as a relatively pure return material for remelting and smelting.
[0109] Comparative Example 5
[0110] Comparative Example 5 involved surface cleaning treatment of GH4738 wrought superalloy scrap. The scrap surface had a processing layer and an oil layer. On the scrap surface, the C content reached 0.25%; the O, N, and S contents were 420 ppm, 83 ppm, and 36 ppm, respectively. The contents of these elements were all much higher than the corresponding element contents in the GH4738 wrought superalloy matrix, and therefore it could not be used as a relatively pure return material for remelting and reuse.
[0111] The surface cleaning treatment method provided in Comparative Example 5 includes the following steps:
[0112] Pre-treatment steps: The GH4738 deformed high-temperature alloy scrap is crushed and screened to uniformly process the size to -8.00mm to +3.35mm, thus obtaining the GH4738 deformed high-temperature alloy scrap to be processed.
[0113] Alkaline cleaning step: Prepare an alkaline cleaning solution, which, by mass percentage, comprises: 1 wt.% octylphenol polyoxyethylene ether (OP-10), 1 wt.% sodium dodecylbenzene sulfonate (SDBS), 1.5 wt.% sodium hydroxide, 3 wt.% sodium carbonate, 0.5 wt.% sodium silicate, and the balance being deionized water. Immerse the GH4738 deformed high-temperature alloy scrap to be treated in the alkaline cleaning solution and perform ultrasonic cleaning to obtain alkaline-treated high-temperature alloy scrap. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the ultrasonic power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 60 minutes. The ratio of the mass of the GH4738 deformed high-temperature alloy scrap to the volume of the alkaline cleaning solution was 1:3 kg / L.
[0114] Pickling Steps: Prepare the pickling solution (including glacial acetic acid, hydrogen peroxide, and water), where the concentration of glacial acetic acid is 3 mol / L and the concentration of H2O2 is 1.3 mol / L. Immerse the alkaline-washed high-temperature alloy scrap into the oxidizing pickling solution for ultrasonic cleaning. The ultrasonic frequency is 40 kHz, the ultrasonic power is 600 W, and the cleaning power density is 0.8 W / cm³. 2 The ultrasonic cleaning process was carried out at a temperature of 40℃ for 30 minutes. After pickling, the material was rinsed twice with deionized water and dried to obtain high-temperature alloy scrap with a cleaned surface.
[0115] In the surface layer of the GH4738 deformed high-temperature alloy scrap obtained after surface cleaning treatment in Comparative Example 5, the contents of C, O, N and S were 0.047%, 60ppm, 33ppm and 10ppm, respectively. Among them, there were more unwashed pickling products remaining on the surface, and the O content was significantly higher than that in the example.
[0116] Since the pickling solution used in Comparative Example 5 does not contain halide ions in its anion, it lacks the conditions for ion vacancy induction and relies solely on H... + Due to the difficulty in achieving the dissolution of the oxide layer with Cr2O3, TiO2, and Al2O3 as the core, the final sample still maintains a high O content, making it unsuitable as a relatively pure return material for remelting and smelting.
[0117] Figure 1 Figure 1 shows the EPMA images of the cross-sectional morphology and elemental distribution of high-temperature alloy scrap samples; (a) is the EPMA image of the cross-sectional morphology and elemental distribution of the high-temperature alloy scrap sample after alkaline washing in Comparative Example 4; (b) is the EPMA image of the cross-sectional morphology and elemental distribution of the high-temperature alloy scrap sample after surface cleaning treatment obtained in Comparative Example 4; (c) is the EPMA image of the cross-sectional morphology and elemental distribution of the high-temperature alloy scrap sample after surface cleaning treatment obtained in Example 1; from Figure 1 This demonstrates that simple alkaline washing cannot achieve thorough cleaning of the surface of high-temperature alloy scrap, and that the hydrogen peroxide component in the pickling solution has a significant effect on removing the processed material. In the comparative example without hydrogen peroxide, even under identical conditions, a certain amount of Al2O3 and TiO2 residue remained after 30 minutes of cleaning. (See [reference]). Figure 1 The elemental spectra of O, Al, and Ti are shown in Figure (b).
[0118] Figure 2 Figure 1 shows the surface morphology and elemental distribution of the high-temperature alloy scrap sample after alkaline washing in Example 1; wherein, (a) Figure 1 shows the surface morphology and elemental distribution of the free surface of the high-temperature alloy scrap sample after alkaline washing; and (b) Figure 1 shows the surface morphology and elemental distribution of the contact surface of the high-temperature alloy scrap sample after alkaline washing. Figure 2 It can be seen that alkaline washing can effectively clean the free surface, but it cannot treat the contact surface. Oxides and nitrides are mainly concentrated in the depressions and grooves of the contact surface, making targeted treatment difficult.
[0119] Figure 3 Figure 1 shows the morphology and elemental distribution of high-temperature alloy scrap samples; (a) Figure 2 shows the morphology and elemental distribution of the high-temperature alloy scrap sample after pickling for 15 min in Comparative Example 4; (b) Figure 3 shows the morphology and elemental distribution of the high-temperature alloy scrap sample after pickling for 15 min in Example 1; (c) Figure 4 shows the morphology and elemental distribution of the contact surface of the high-temperature alloy scrap sample after pickling for 30 min in Example 1; (d) Figure 5 shows the morphology and elemental distribution of the free surface of the high-temperature alloy scrap sample after pickling for 30 min in Example 1. Figure 3It can be seen that in Example 1, the pickling process only lasted 15 minutes, which was insufficient to completely remove surface impurities. Only after 30 minutes of pickling was the surface thoroughly cleaned. Compared with Comparative Example 4, Example 1 showed superior cleaning results, with the processed layer being peeled off in the pickling solution, indicating that hydrogen peroxide plays a crucial role in the cleaning effect. It can be seen that the amount of hydrogen peroxide in the pickling solution and the pickling time are two critical parameters, neither of which can be omitted. Only by simultaneously controlling both (hydrogen peroxide concentration of 0.4~2.2 mol / L and pickling time of 30~45 min) can the complete peeling off of the processed material layer be achieved.
[0120] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.
Claims
1. A method for surface cleaning treatment of high-temperature alloy scrap, characterized in that, It includes the following steps: Alkaline washing step: The high-temperature alloy scrap to be treated is cleaned with an alkaline cleaning solution to remove the oil and dirt layer covering the surface of the high-temperature alloy scrap to be treated. A high-temperature alloy scrap material after alkaline washing is obtained; wherein, by mass percentage, the alkaline cleaning solution comprises: 0.1~4 wt.% emulsifier, 2~6 wt.% alkaline additive, 0.2~1 wt.% flocculant, and the balance being water; wherein, the emulsifier comprises ionic surfactants and nonionic surfactants; Pickling step: The high-temperature alloy scrap after alkaline washing is cleaned with an oxidizing pickling solution to remove the surface processing layer on the high-temperature alloy scrap; after washing with water and drying, the high-temperature alloy scrap after surface cleaning treatment is obtained; wherein, the oxidizing pickling solution includes hydrohalic acid, oxidizing substances with hydroxyl bond structure and water.
2. The method for surface cleaning treatment of high-temperature alloy scrap according to claim 1, characterized in that, The high-temperature alloy chips to be processed are chips generated during machining; and / or The surface of the high-temperature alloy scrap to be processed has a processing layer formed during the processing; an oil stain layer adheres to the surface of the processing layer; wherein the processing layer includes oxides; Preferably, the oxide comprises chromium oxide; Preferably, the oil layer comprises cutting oil; more preferably, the cutting oil comprises coolant, organic rust inhibitor, bactericide, and extreme pressure additive.
3. The method for surface cleaning treatment of high-temperature alloy scrap according to claim 1 or 2, characterized in that, The high-temperature alloy scrap to be processed is deformed high-temperature alloy scrap.
4. The method for surface cleaning treatment of high-temperature alloy scrap according to any one of claims 1-3, characterized in that, The ionic surfactant is selected from at least one of alkyl sulfates and alkyl sulfonates; more preferably, the ionic surfactant is selected from sodium dodecylbenzene sulfonate (SDBS) and / or sodium dodecyl sulfate (SDS); and / or The nonionic surfactant is selected from nonionic surfactants with an HLB value between 8 and 18, preferably at least one of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and alkyl glycoside; more preferably, the nonionic surfactant is selected from one or more of octylphenol polyoxyethylene ether OP-10, fatty alcohol polyoxyethylene ether (AEO-9), and alkyl glycoside (APG-0810); and / or The mass ratio of the nonionic surfactant to the ionic surfactant is 1:1 to 3:
1.
5. The method for surface cleaning treatment of high-temperature alloy scrap according to any one of claims 1-4, characterized in that, The alkaline additives include sodium hydroxide and sodium carbonate; wherein, in the alkaline cleaning solution: the mass fraction of sodium hydroxide is 1~3% and the mass fraction of sodium carbonate is 1~3%.
6. The method for surface cleaning treatment of high-temperature alloy scrap according to any one of claims 1-5, characterized in that, Sodium silicate is selected as the flocculant.
7. The method for surface cleaning treatment of high-temperature alloy scrap according to any one of claims 1-6, characterized in that, In the alkaline washing step: The high-temperature alloy scrap to be treated is immersed in the alkaline cleaning solution for ultrasonic cleaning. Preferably, the ultrasonic cleaning process is carried out at a temperature below 60°C, more preferably between 25°C and 50°C; the ultrasonic power is 300-600W, and the ultrasonic power density is 0.4-0.8W / cm³. 2 The ultrasonic cleaning process takes 30-90 minutes. Preferably, the ratio of the mass of the high-temperature alloy scrap to the volume of the alkaline cleaning solution is 1:1 to 1:5, in kg / L, and preferably 1:
2.
8. The method for surface cleaning treatment of high-temperature alloy scrap according to any one of claims 1-7, characterized in that, In the oxidizing pickling solution: The oxidizing agent with a hydroxyl bond structure is selected as hydrogen peroxide; the hydrogen halide is hydrochloric acid; preferably, the concentration of the hydrochloric acid is 2~4 mol / L and the concentration of the hydrogen peroxide is 0.4~2.2 mol / L.
9. The method for surface cleaning treatment of high-temperature alloy scrap according to any one of claims 1-8, characterized in that, In the pickling step: The high-temperature alloy scrap after alkaline washing is immersed in an oxidizing pickling solution for ultrasonic cleaning; preferably, the ultrasonic cleaning temperature is below 60°C, more preferably 20~50°C, the ultrasonic power is 300~600W, and the ultrasonic power density is 0.4~0.8W / cm³. 2 The ultrasonic cleaning time is 15~45min, preferably 30~45min.
10. The method for surface cleaning treatment of high-temperature alloy scrap according to any one of claims 1-9, characterized in that, In the alkaline washing step: after cleaning, the high-temperature alloy chips treated with the alkaline cleaning solution need to be rinsed with deionized water; and / or In the pickling step, the water washing involves rinsing the high-temperature alloy scrap after the oxidizing pickling solution treatment with deionized water; and / or The oxygen content in the surface layer of the high-temperature alloy scrap after surface cleaning treatment is ≤50ppm, the nitrogen content is ≤25ppm, and the sulfur content is less than 10ppm.