Surface impurity removal method for electrodeposited nickel starting sheet lug material for high-temperature alloy smelting

Abstract

The invention relates to the technical field of cast high-temperature alloy smelting, in particular to a surface impurity removal method of an electrodeposited nickel starting sheet lug material for high-temperature alloy smelting, which comprises the following steps: S1, vibration pretreatment; s2, high-temperature cleaning; s2, after treatment in S2 is completed, liquid in a cleaning tank is discharged, a sulfuric acid solution with the mass concentration being 10%-15% is added into the cleaning tank, a throw-in type ultrasonic cleaning rod is immersed into the sulfuric acid solution, and the throw-in type ultrasonic cleaning rod is powered on for ultrasonic acid pickling treatment; s4, low-temperature drying is conducted, after treatment in the S3 is completed, the sulfuric acid solution in the cleaning tank is discharged, and the cleaning tank containing the lug materials is put into a trolley type resistance furnace to be heated and dried; and S5, shot blasting final treatment. According to the method, a gradient purification system is formed, impurities are thoroughly removed, residues of harmful elements S and P can be reduced, it is guaranteed that components of the high-temperature alloy casting are stable, the performance is excellent, pure smelting is achieved, the smelting efficiency is improved, the cost of the electrodeposited nickel starting sheet lug is lower than that of electrolytic nickel, and the production cost is remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of casting high-temperature alloy smelting technology, specifically to a method for surface impurity removal of electrolytic nickel starter sheet lugs used in high-temperature alloy smelting. Background Technology

[0002] High-temperature alloys exhibit stable microstructure and excellent mechanical, physical, and chemical properties under high-temperature operating conditions above 650℃, and are widely used in industries such as aerospace, aviation, and petrochemicals. Nickel is one of the main components of high-temperature alloys and has a certain impact on their high-temperature performance. To achieve the target nickel content during the high-temperature alloy smelting process, using high-purity electrolytic nickel (purity ≥99.9%) as the nickel source can avoid compositional fluctuations during smelting. However, electrolytic nickel is expensive, increasing production costs.

[0003] Currently, using the starting electrode lugs generated during the electrolytic nickel production process for the smelting of high-temperature alloys to achieve the target nickel content has certain advantages in the production of high-temperature alloy castings. However, due to the incomplete electrolysis of the starting electrode lugs during the electrolytic nickel production process, a large number of residual impurities (such as loose dust, fine metal fragments, nickel sulfate particles, nickel oxide layers, etc.) remain on the surface of the lugs. Therefore, its performance is not as good as that of electrolytic nickel, which makes its advantages less obvious in the application of high-performance high-temperature alloy castings in special fields.

[0004] Current traditional impurity removal processes in the industry are mostly two-step methods combining mechanical vibration and single acid pickling. These methods can only separate some loose impurities through mechanical vibration and dissolve a small amount of oxides through single acid pickling. They lack a specific step to treat adhered substances and stubborn residual impurities, resulting in limited impurity removal efficiency (total impurity removal rate of only 60-65%). Furthermore, traditional impurity removal processes easily damage the ear-shaped alloy substrate, and residual impurities during smelting increase smelting losses and reduce smelting efficiency, further limiting the application of electrolytic nickel starter sheets. Therefore, when using electrolytic nickel starter sheets for high-performance high-temperature alloy smelting, it is crucial to address the residual impurities from electrolytic electrolysis on their surface, reduce the impact of harmful elements such as sulfur (S) and phosphorus (P), achieve pure smelting, reduce smelting losses, improve smelting efficiency, avoid damage to the ear-shaped alloy substrate caused by traditional processes, and simultaneously ensure the high performance of high-temperature alloy castings. This achieves the effect of using electrolytic nickel while reducing production costs, and is a pressing issue that needs to be resolved. Summary of the Invention

[0005] The purpose of this invention is to provide a method for removing surface impurities from electrolytic nickel starter sheet lugs used in high-temperature alloy smelting. This method addresses the technical problems of incomplete removal of surface impurities and high residual levels of harmful elements (S / P) in electrolytic nickel starter sheet lugs, which lead to low purity in high-temperature alloy smelting, unstable casting performance, and high production costs.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This application provides a method for surface impurity removal of electrolytic nickel starter sheet material for high-temperature alloy smelting, comprising the following steps: S1. Vibration pretreatment: Before smelting, a vibrating screen is used to screen the electrolytic nickel starting sheet material to separate the loose dust and fine metal fragments attached to the surface of the material. S2. High-temperature cleaning: The electrolytic nickel starting sheet material treated in S1 is placed in a cleaning tank, and high-temperature steam is introduced into the cleaning tank to clean the material. S3, Ultrasonic pickling: After the S2 treatment is completed, drain the liquid in the cleaning tank, add a sulfuric acid solution with a mass concentration of 10-15% to the cleaning tank, immerse the submersible ultrasonic cleaning rod in the sulfuric acid solution, and perform ultrasonic pickling treatment by turning on the power. S4. Low-temperature drying: After the S3 treatment is completed, the sulfuric acid solution in the cleaning tank is discharged, and the cleaning tank containing the ear material is placed in a trolley-type resistance furnace for heating and drying. S5. Final shot peening treatment: The electrolytic nickel starting sheet material dried in S4 is taken out from the cleaning tank and placed into the shot peening machine for shot peening treatment.

[0007] Furthermore, the vibration frequency of the vibrating screen in S1 is 15-25Hz, and the amplitude is 1-3mm; the pressure of the high-temperature steam in S2 is 0.2-0.3MPa, the cleaning temperature is 150-200℃, and the cleaning time is 10-15min.

[0008] Furthermore, the ultrasonic pickling process described in S3 is performed at a temperature of 40-60°C for 15-20 minutes.

[0009] Furthermore, the heating temperature for low-temperature drying described in S4 is 100-120℃, and the holding time is 25-30 minutes.

[0010] Furthermore, in S5, the shot used for shot peening is stainless steel shot with a diameter of 0.8 mm, and the shot peening time is 10-15 min.

[0011] Furthermore, the amount of sulfuric acid solution added in S3 is based on completely immersing the electrodeposited nickel starter sheet material.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses a gradient impurity removal scheme (vibration pretreatment → high temperature cleaning → ultrasonic acid washing → low temperature drying → shot peening final treatment) to specifically remove different types of impurities from the surface of ear material, avoid secondary adhesion of impurities, and achieve efficient and comprehensive surface purification. The total impurity removal efficiency is more than 30% higher than the traditional "mechanical vibration combined with single acid washing" process.

[0013] 2. Through the synergistic effect of ultrasonic pickling and shot peening final treatment, the residual amount of harmful elements S and P is effectively reduced, ensuring the stability of the composition and high performance of high-temperature alloy castings. At the same time, it avoids the damage to the ear material substrate caused by traditional processes and improves the utilization rate of ear material.

[0014] 3. This invention achieves multiple objectives, including complete removal of impurities, improved smelting efficiency, matrix protection, and cost reduction. It is particularly suitable for high-temperature alloy smelting where surface cleanliness and elemental stability are extremely important, and successfully replaces expensive electrolytic nickel with low-cost electrolytic nickel lump material. Attached Figure Description

[0015] Figure 1 This is a process flow diagram of a surface impurity removal method for electrolytic nickel starting material used in high-temperature alloy smelting according to the present invention. Detailed Implementation

[0016] To better understand the technical content of this invention, the following detailed description of the invention is provided in conjunction with specific examples.

[0017] like Figure 1 As shown, a method for surface impurity removal of electrolytic nickel starter sheet material for high-temperature alloy smelting is described. Includes the following steps: S1. Vibration pretreatment: Before smelting, a vibrating screen is used to screen the starting material of the electrolytic nickel sheet to separate the loose dust and fine metal debris attached to the surface of the material, reduce the impurity load in subsequent steps, and avoid the secondary adhesion of such impurities during the cleaning process; the vibration frequency of the vibrating screen is 15-25Hz and the amplitude is 1-3mm. S2. High-temperature cleaning: The electrolytic nickel starting sheet material treated in S1 is placed in the cleaning tank, and high-temperature steam is introduced into the cleaning tank to clean the material, soften and remove organic adhering substances such as nickel sulfate particles, and specifically treat organic and semi-adhered impurities; the pressure of the high-temperature steam is 0.2-0.3MPa, the cleaning temperature is 150-200℃, and the cleaning time is 10-15min; the cleaning tank is equipped with a high-temperature steam inlet, a waste liquid outlet, and an ultrasonic cleaning rod mounting position, and the position layout of the inlet, outlet, and mounting position is adapted to the continuous operation process of high-temperature steam cleaning and ultrasonic acid washing; S3. Ultrasonic pickling: After the S2 treatment is completed, drain the liquid in the cleaning tank, add a sulfuric acid solution with a mass concentration of 10-15% to the cleaning tank, immerse the submersible ultrasonic cleaning rod in the sulfuric acid solution, and perform ultrasonic pickling treatment by turning on the power to chemically dissolve the nickel oxide layer and other metal impurities on the surface; the ultrasonic pickling treatment temperature is 40-60℃, and the ultrasonic treatment time is 15-20min; the 10-15% sulfuric acid solution corresponds to a sulfuric acid to water volume ratio of 1:9.8-1:6.3.

[0018] S4. Low-temperature drying: After the S3 treatment is completed, drain the sulfuric acid solution from the cleaning tank, place the cleaning tank containing the ear material into a trolley-type resistance furnace, and heat and dry it to dry and remove the impurities dissolved on the surface. The heating temperature for low-temperature drying is 100-120℃, and the holding time is 25-30 minutes. The amount of sulfuric acid solution added is enough to completely immerse the electrolytic nickel starting sheet ear material. S5. Final shot peening treatment: The electrolytic nickel starting sheet material dried in S4 is taken out of the cleaning tank and placed in the shot peening machine for shot peening treatment to clean the surface impurities; the shot used for shot peening treatment is stainless steel shot with a diameter of 0.8mm, and the shot peening treatment time is 10-15min.

[0019] The present invention discloses a surface impurity removal method for electro-concentrated nickel starter sheet lugs used in high-temperature alloy smelting. The treated electro-concentrated nickel starter sheet lugs are used to smelt high-temperature alloy castings. The chemical composition of the high-temperature alloy castings meets the following requirements: C: 0.40-0.60%, Si≤1.75%, Mn≤1.5%, P≤0.03%, S≤0.03%, Cr: 27.0-30.0%, Ni: 47.0-50.0%, W: 4.0-6.0%, with the remainder being iron.

[0020] [Example] The following parameters are all within the scope defined in the claims and are preferred embodiments. The main steps of the surface impurity removal method for electrowinning nickel starter sheet lugs used in high-temperature alloy smelting according to the present invention are as follows: S1. Vibration pretreatment: Before smelting, a vibrating screen is used to screen the nickel electrode material to separate the loose dust and fine metal fragments attached to the surface of the material. At the same time, the vibration frequency and amplitude are adjusted to control the separation speed of impurities, so as to achieve the effect of quickly removing solid impurities, thereby reducing the impurity load in subsequent steps and avoiding the secondary adhesion of such impurities during the cleaning process. S2. High-temperature cleaning: The electrolytic nickel starting sheet ear material after S1 treatment is placed in the cleaning tank, and high-temperature steam is introduced into the cleaning tank to clean the ear material, soften and peel off organic adhering substances such as nickel sulfate particles, and specifically treat organic and semi-adhered impurities. The pressure of the high-temperature steam is set to 25MPa, the cleaning temperature is set to 180℃, and the cleaning time is set to 13min. After S3 and S2 treatments are completed, drain the liquid from the cleaning tank, add 15% sulfuric acid solution (the volume ratio of sulfuric acid to water is 1:6.3) to the cleaning tank to cover the ear material, heat the solution to 50°C, immerse the submersible ultrasonic cleaning rod in the sulfuric acid solution, set the ultrasonic vibration time to 17 minutes, and perform ultrasonic acid washing treatment by powering on to chemically dissolve the nickel oxide layer and other metal impurities on the surface. After S4 and S3 are completed, drain the waste liquid in the cleaning tank and put the cleaning tank into a trolley-type resistance furnace to heat to 105℃ and keep it at that temperature for 25 minutes to dry it, so that the impurities dissolved on the surface are completely dried and removed. S5. Take the electrode material of nickel-concentrated starting sheet after drying in S4 out of the cleaning tank and put it into the shot peening machine. Select stainless steel shot with a diameter of 0.8mm and set the shot peening time to 15min to perform shot peening treatment to thoroughly clean the impurities on the surface.

[0021] In the above specific examples, the surface impurity removal method of the electrolytic nickel starting sheet lug for high-temperature alloy smelting of the present invention was used to remove impurities from the lug surface and to smelt high-temperature alloy castings. This achieved rapid nickel addition, reduced the interference of harmful elements S and P, and resulted in castings with stable chemical composition and performance that fully met the requirements for use.

[0022] Table 1 shows the chemical composition of the high-temperature alloy castings produced in the above embodiments, obtained by direct-reading spectrometer.

[0023] chemical composition C Si Mn P S Cr Ni W standard(%) 0.40-0.60 ≤1.75 ≤1.5 ≤0.030 ≤0.030 27.0-30.0 47.0-50.0 4.0-6.0 Detection value (%) 0.441 1.508 1.275 0.015 0.011 27.84 48.17 4.143 To further verify the technical advantages of this invention, the novel process of this invention was compared with conventional impurity removal processes in the industry from multiple dimensions. The results are shown in Table 2 below: Table 2 compares the multi-dimensional effects of traditional impurity removal processes with the novel process of this invention. Comparison content Traditional process (mechanical vibration + single pickling) This invention's new process Impurity removal process 2-step process: Mechanical vibration (separation of loose impurities) → Single acid washing (dissolving some oxides), no subsequent strengthening treatment. Five steps: vibration pretreatment → high-temperature cleaning → ultrasonic pickling → low-temperature drying → shot peening final treatment, forming a gradient purification system. Impurity removal rate (core indicator) Oxide removal rate: 65-70%; Nickel sulfate particle removal rate: 50-55%; Total impurity removal rate: 60-65%. Oxide removal rate ≥ 99.2%; nickel sulfate particle removal rate ≥ 99.5%; total impurity removal rate ≥ 99.0% (based on test results from the example). Residual levels of harmful elements S and P (ppm) S residue 450~550ppm (0.045%~0.055%); P residue 400~500ppm (0.040%~0.050%), easily exceeding the upper limit of the casting standard (≤300ppm, i.e. 0.03%). S residue 110 ppm (0.011%); P residue 150 ppm (0.015%) (sample test values), far below the standard upper limit. Compositional stability of high-temperature alloy castings The fluctuation range for Ni is ±1.5-2.0%; the fluctuation range for other key elements (Cr, W) is ±0.8-1.2%, which may easily lead to excessive levels of these elements. The Ni element fluctuation range is ±0.5-0.8% (Ni detection value in the example is 48.17%, standard is 47.0-50.0%); the Cr and W fluctuation ranges are ±0.3-0.5%. Smelting efficiency Due to the high level of impurities remaining, additional time is required for impurity removal during the smelting process. The smelting cycle for a single furnace is 8-10 hours, with a smelting efficiency of approximately 75%. Impurities are removed efficiently in advance, reducing the single-furnace smelting cycle to 5-6 hours and increasing smelting efficiency to over 95%. Ear material utilization rate Residual impurities result in only 70-75% of the ear material being usable, with some ear material being unusable due to excessive impurities. The ear material surface cleanliness meets the standards, the effective utilization rate is increased to over 98%, and there is almost no waste ear material. Production cost (RMB / ton of castings) 1. Low utilization rate of raw materials, requiring the replenishment of expensive electrolytic nickel (approximately 120,000 RMB / ton); 2. Time-consuming and energy-intensive smelting process; the overall cost is approximately 8,500-9,000 RMB. 1. High utilization rate of ear-shaped raw materials, no need to replenish electrolytic nickel (ear-shaped raw material price is only 60% of electrolytic nickel); 2. Short smelting cycle and low energy consumption; comprehensive cost is approximately 4500-5000 yuan. Casting qualification rate Due to impurities and fluctuations in composition, the mechanical properties and temperature resistance of castings are prone to failing to meet standards, with a pass rate of only 65-70%. The castings have stable composition and low impurity residue, and their performance fully meets the requirements for high-temperature alloy use, with the pass rate increased to over 99%. Craftsmanship Creativity It only targets loose impurities and some oxides, lacks specific impurity removal design, has a simplistic process, and lacks innovation. 1. Gradient impurity removal: physical separation → removal of organic adhering substances → chemical dissolution → drying to remove impurities → removal of stubborn impurities, progressing step by step; 2. Targeted enhancement: high-temperature steam softening of nickel sulfate, ultrasonic enhancement of pickling effect, shot peening to remove impurities in dead corners, solving the pain points of traditional processes. Note: Traditional process refers to the industry's conventional "mechanical vibration + single pickling" impurity removal method (without high-temperature cleaning, low-temperature drying, and shot peening final treatment steps); new process refers to the five-step method disclosed in this invention: "vibration pretreatment → high-temperature cleaning → ultrasonic pickling → low-temperature drying → shot peening final treatment"; comparative data are all based on tests conducted on the same batch of electrolytic nickel starting material (with consistent initial impurity content) and the same high-temperature alloy smelting conditions (target composition: C: 0.40-0.60%, Si≤1.75%, Mn≤1.5%, P≤0.03%, S≤0.03%, Cr: 27.0-30.0%, Ni: 47.0-50.0%, W: 4.0-6.0%, the remainder being iron), ensuring the objectivity and comparability of the data.

[0024] Comparative analysis revealed that the new process of this invention, through multi-step synergistic optimization, far surpasses traditional processes in key dimensions such as impurity removal effect, composition stability, smelting efficiency, and cost control. In particular, it solves the core pain points of traditional processes, such as incomplete impurity removal, high residual harmful elements, and low casting qualification rate. It achieves the dual goals of pure smelting of high-temperature alloys and low-cost production, demonstrating outstanding creativity and significant application value.

[0025] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for surface impurity removal of electrolytic nickel starter sheet feedstock for high-temperature alloy smelting, characterized in that, Includes the following steps: S1. Vibration pretreatment: Before smelting, the electrolytic nickel starting sheet material is screened using a vibrating screen to separate the loose dust and fine metal fragments attached to the surface of the material. S2. High-temperature cleaning: The electrolytic nickel starting sheet material treated in S1 is placed in a cleaning tank, and high-temperature steam is introduced into the cleaning tank to clean the material. S3, Ultrasonic pickling: After the S2 treatment is completed, drain the liquid in the cleaning tank, add a sulfuric acid solution with a mass concentration of 10-15% to the cleaning tank, immerse the submersible ultrasonic cleaning rod in the sulfuric acid solution, and perform ultrasonic pickling treatment by turning on the power. S4. Low-temperature drying: After the S3 treatment is completed, the sulfuric acid solution in the cleaning tank is discharged, and the cleaning tank containing the ear material is placed in a trolley-type resistance furnace for heating and drying. S5. Final shot peening treatment: The electrode stock material dried in S4 is taken out from the cleaning tank and placed into the shot peening machine for shot peening treatment.

2. The method for surface impurity removal of electrolytic nickel starter sheet material for high-temperature alloy smelting according to claim 1, characterized in that, The vibration frequency of the vibrating screen in S1 is 15-25Hz and the amplitude is 1-3mm; the pressure of the high-temperature steam in S2 is 0.2-0.3MPa, the cleaning temperature is 150-200℃, and the cleaning time is 10-15min.

3. The method for surface impurity removal of electrolytic nickel starter sheet material for high-temperature alloy smelting according to claim 1, characterized in that, The ultrasonic pickling process described in S3 is performed at a temperature of 40-60℃ for 15-20 minutes.

4. The method for surface impurity removal of electrolytic nickel starter sheet material for high-temperature alloy smelting according to claim 1, characterized in that, The heating temperature for low-temperature drying described in S4 is 100-120℃, and the holding time is 25-30 minutes.

5. The method for surface impurity removal of electrolytic nickel starter sheet material for high-temperature alloy smelting according to claim 1, characterized in that, The shot used in the shot peening process described in S5 is stainless steel shot with a diameter of 0.8 mm, and the shot peening process lasts for 10-15 minutes.

6. The method for surface impurity removal of electrolytic nickel starter sheet lugs for high-temperature alloy smelting according to claim 1, characterized in that, The amount of sulfuric acid solution added in S3 is based on completely immersing the nickel electrode stock.

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