A surface treatment method for resisting metal dust adhesion

Abstract

The application discloses a surface treatment method for resisting metal powder chip adhesion. The method comprises the following steps: performing surface nanocrystallization treatment on a base material, so that nanocrystals are formed on the surface of the base material, and a surface-nanocrystallized base material is obtained; and performing thermal oxidation treatment or chemical oxidation treatment on the surface-nanocrystallized base material, so that a pre-oxidation layer is formed on the nanocrystals, and a base material with resistance to metal powder chip adhesion is obtained. The base material treated by the method can have the performance of resisting metal powder chip adhesion in a metal processing process, thereby prolonging the service life and reducing the metal plate strip processing defective product rate.

Description

Technical Field

[0001] This invention belongs to the field of metal material surface treatment technology, specifically a surface treatment method for preventing metal powder adhesion. It is a surface treatment technology applicable to metal material tools used in the processing of metal sheets and strips, especially roll tools. Background Technology

[0002] Metal sheet and strip rolling is a crucial step in metal product processing. The surface quality of the rolls directly affects the surface quality of the metal sheet and strip, especially in aluminum processing, copper processing, and galvanized sheet processing. Figure 1 and Figure 2 As shown, during aluminum processing, straightening rolls, guide rolls, tension rolls, and conveyor rolls often suffer from aluminum powder adhesion, leading to ring marks and powder accumulation on the roll surface, thus affecting production efficiency. Furthermore, work rolls used in aluminum sheet and strip processing also experience a decrease in surface roughness due to aluminum adhesion. Consequently, after rolling a certain number of aluminum sheets and strips, the forward slip value decreases, making the rolling process prone to slippage and affecting product quality. Similar situations also occur in the processing of phosphor bronze and galvanized sheets.

[0003] Therefore, there is a need for a surface treatment technology that can enhance the resistance of metal dust adhesion to tools used in sheet and strip processing, especially rolling tools, in order to reduce the frequency of roll changes and achieve efficient processing and rolling of sheet and strip. Summary of the Invention

[0004] The purpose of this invention is to provide a surface treatment method for preventing metal powder adhesion, namely, performing a surface nano-processing treatment on the substrate surface to make the substrate surface nanocrystalline, and then combining it with a pre-oxidation treatment to form a thin layer of nanocrystalline oxide, thereby preventing the substrate from contacting metal powder and achieving the purpose of anti-adhesion.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a surface treatment method for preventing metal dust adhesion. The method includes: performing a surface nano-treatment on a substrate to form nanocrystals on the surface of the substrate, thereby obtaining a surface-nano-treated substrate; and then performing a thermal oxidation treatment or a chemical oxidation treatment on the surface-nano-treated substrate to form a pre-oxidized layer on the nanocrystals, thereby obtaining a substrate with resistance to metal dust adhesion.

[0006] It should be noted that the surface nanocrystals enhance the mechanical properties of the substrate surface and provide rapid diffusion channels for the nucleation of the subsequent pre-oxidation layer. The pre-oxidation layer, on the other hand, acts as a protective layer on the substrate surface. On one hand, its high adhesion ensures the mechanical properties of the substrate surface; on the other hand, it separates the substrate from metal dust, effectively preventing metal dust adhesion. Specifically, this is a surface treatment method for metallic substrates, where the pre-oxidation layer formed after thermal or chemical oxidation has a thickness of 1-100 nm. More specifically, this pre-oxidation layer is a metal oxide layer.

[0007] Furthermore, the thermal oxidation treatment includes: tempering the nano-sized substrate at a tempering temperature for 0.5-20 h under atmospheric conditions.

[0008] Furthermore, the thermal oxidation treatment includes: pre-oxidizing the nano-sized substrate; wherein the oxygen partial pressure of the pre-oxidation treatment is adapted to the material of the substrate, and the temperature of the pre-oxidation treatment does not exceed the tempering temperature of the substrate. It is understood that the pre-oxidation treatment time also depends on the material of the substrate. Preferably, the pre-oxidation treatment time is sufficient to form a pre-oxidized layer with a thickness of 1-100 nm on the substrate surface. Increasing the depth of the pre-oxidized layer while ensuring its excellent mechanical properties further enhances the anti-metal adhesion effect.

[0009] Furthermore, the chemical oxidation treatment includes: subjecting the nano-sized substrate to alkaline oxidation treatment at 135-155°C for 1-20 min; preferably, before the alkaline oxidation treatment, the nano-sized substrate is subjected to surface cleaning, acid pickling activation and water washing treatment in sequence.

[0010] It is evident that, regardless of whether thermal oxidation or chemical oxidation is used, the goal is to obtain a dense nanocrystalline oxide layer on the substrate after surface nano-sizing.

[0011] Furthermore, between the surface nano-sizing treatment and the thermal or chemical oxidation treatment, the process includes: combining grinding to process the nano-sized substrate to meet the requirements for machine use. Specifically, combining grinding to process the nano-sized roll to meet the requirements for machine use includes: using a grinding machine to process the nano-sized roll to the surface roughness and precision requirements for machine use. Then, the nano-sized substrate is cleaned to ensure its surface is free of dust and oil.

[0012] Furthermore, the surface nano-sizing treatment includes: performing surface nano-sizing treatment on the substrate using a specialized surface nano-sizing machine or CNC lathe, specifically surface mechanical grinding, surface mechanical rolling, or surface mechanical pressing technology, to form nanocrystals on the substrate surface. It is understood that surface nano-sizing treatment can also be performed using other methods such as shot peening.

[0013] The present invention also provides a substrate with resistance to metal dust adhesion, the substrate comprising a body, nanocrystals formed on the surface of the body, and a pre-oxidized layer formed on the nanocrystals; wherein the substrate is made of metal, and the pre-oxidized layer is a metal oxide layer with a thickness of 1-100 nm. Specifically, the substrate is a rolling mill roll. Preferably, the substrate with resistance to metal dust adhesion can be obtained by the above-described surface treatment method for resisting metal dust adhesion.

[0014] Furthermore, the nanocrystalline layer is obtained by surface nano-sizing of the substrate, and the pre-oxidized layer is obtained by further thermal oxidation or chemical oxidation of the substrate.

[0015] It should be noted that in this invention, nanocrystals are prepared on the surface of the substrate by performing a surface nano-sizing treatment, thereby enhancing the overall surface mechanical properties of the substrate and providing a rapid diffusion channel for the subsequent nucleation of the pre-oxidized layer. After the surface nano-sizing treatment, a protective nanocrystalline pre-oxidized layer is formed through a pre-oxidation treatment. The high bonding strength and toughness of this pre-oxidized layer ensure the mechanical properties of the outermost layer of the substrate, while separating the substrate from metal powder to establish metal bonding, thereby preventing metal powder from adhering to the rolls. Specifically, this pre-oxidized layer is a relatively thin metal oxide layer.

[0016] The present invention also provides the application of the above-mentioned substrate with anti-metal dust adhesion in the field of metal sheet and strip rolling.

[0017] Furthermore, the metal sheet and strip rolling process includes aluminum processing, copper processing, galvanized sheet processing, and other metal processing.

[0018] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages: This invention provides a surface treatment method to prevent metal powder adhesion. By performing a nano-scale treatment on the substrate, the refined nanocrystals enhance the substrate's wear resistance and fatigue life. Combined with a pre-oxidation treatment, this prevents metal powder from contacting the substrate, thus achieving an anti-adhesion effect. Simultaneously, the thin nano-oxidized layer possesses excellent toughness and good adhesion to the substrate, ensuring the substrate's surface mechanical properties while achieving anti-adhesion. This method is simple to operate, non-destructive, and can achieve anti-adhesion of metal powder (anti-adhesion of aluminum, phosphor bronze, etc.) to the substrate, thereby improving roll life and reducing the reject rate in metal sheet and strip processing. Attached Figure Description

[0019] Figure 1 This is a morphology diagram of aluminum adhesion on the surface of the aluminum processing work roll in the background of this invention; Figure 2 for Figure 1 Aluminum element distribution diagram in [the image / image]; Figure 3 This refers to the pre-oxidized layer obtained by pre-oxidizing the GCr15 roll at 150°C for 18 hours in Example 1 of the present invention. Figure 4 This describes the aluminum adhesion situation of the original GCr15 roll in Embodiment 1 of the present invention; Figure 5 This describes the aluminum adhesion situation of the original GCr15 roll after pre-oxidation treatment at 150°C for 18 hours in Example 1 of this invention; Figure 6 This describes the aluminum adhesion situation of the surface-nanosized GCr15 roll in Example 1 of the present invention; Figure 7 This describes the aluminum adhesion situation of the surface-nanosized GCr15 rolls in Example 1 of the present invention after 18 hours of pre-oxidation treatment at 150°C. Figure 8 This is the aluminum adhesion situation of the surface nano-sized GCr15 roll after 4 hours of pre-oxidation treatment at 150°C in Example 2 of the present invention. Detailed Implementation

[0020] As is known from the background art, metal dust is inevitably generated during the processing of metal sheets and strips. This metal dust interacts with the surface of tools, especially metal tools such as rolls, and adheres to them, causing defects on the surface of the rolls and affecting the quality of the sheet and strip.

[0021] Taking a rolling mill roll as an example, the inventors discovered that the adhesion of metal dust to the roll is caused by cold-pressed welding of metal. Since strip processing easily generates metal dust, when this dust is located between the roll and the strip during rolling, it comes into contact with the roll substrate under friction and pressure, resulting in cold-pressed welding. However, forming a 1-100 nm nanocrystalline oxide layer on the roll surface can prevent contact between the roll and the metal dust, breaking the necessary conditions for interatomic bonding and thus preventing the roll from adhering to metal dust.

[0022] Therefore, the present invention provides a surface treatment method for preventing metal dust adhesion, which is a surface treatment method for tools used in metal processing scenarios that come into contact with metal dust, specifically a surface treatment method for preventing metal dust adhesion of roll-type tools.

[0023] The surface treatment method provided by the present invention is as follows: after performing surface nano-sizing treatment on the substrate, nanocrystals are formed on the surface of the substrate to obtain a substrate with surface nano-sizing; then, the substrate with surface nano-sizing is subjected to thermal oxidation treatment or chemical oxidation treatment to form a pre-oxidation layer on the nanocrystals to obtain a substrate with resistance to metal powder adhesion.

[0024] In addition, a 1-100 nm pre-oxidized layer, which is a nanocrystalline oxide layer, is formed on the surface of the roll. This layer has good adhesion to the roll substrate and does not affect the mechanical properties of the roll. It can enhance the anti-metal powder adhesion characteristics while ensuring the mechanical properties of the roll.

[0025] The present invention will now be described in detail with reference to specific embodiments and taking rolling mill rolls as an example.

[0026] This invention provides a surface treatment method for preventing metal powder adhesion, the method comprising: (1) The surface of the roll is nano-treated using a special surface nano-processing machine or CNC lathe. Options include surface mechanical grinding, surface mechanical rolling, and surface mechanical pressing, resulting in a nanocrystalline surface. Combined with grinding, the roll is processed to meet the surface roughness and precision requirements for use on the machine. (2) The surface of the rolls is cleaned and free of dust and oil; (3) Pre-oxidation treatment of surface nano-sized rolls: There are three main types of pre-oxidation treatment. The first type is to heat the roll surface to the tempering temperature for 0.5-20 h under atmospheric conditions to obtain a 1-100 nm nanocrystalline oxide layer. Or, this invention aims to generate a 1-100 nm nanocrystalline oxide layer on the roll surface. The second type is to change the oxygen partial pressure for pre-oxidation treatment, but considering mechanical properties, the pre-oxidation temperature should not exceed the tempering temperature. The third type is a chemical treatment method, that is, after cleaning the surface of the surface nano-sized roll, acid pickling and activation are performed, followed by water washing, and alkaline oxidation at 135-155℃ for 1-20 min to obtain a dense pre-oxide layer.

[0027] Example 1 GCr15 rolls (aluminum machining straightening rolls) underwent surface nano-sizing treatment. The nano-sizing parameters were: rotation speed 300 rpm, feed rate 0.02 mm / r, single-pass reduction of 200 μm, and the nano-sizing tool was a 6 mm diameter YG6 cemented carbide ball. After processing, the rolls were washed and cleaned, followed by pre-oxidation treatment at 150℃ for 18 hours to obtain the desired result. Figure 3 The 10-20 nm pre-oxidized layer is shown. For comparison, four samples were used: a raw GCr15 roll sample, a raw GCr15 roll sample pre-oxidized at 150℃ for 18 hours, a surface nano-sized sample, and a surface nano-sized sample pre-oxidized at 150℃ for 18 hours. The surface hardness of the roll after pre-oxidation was the same as before treatment. Friction simulation tests were then conducted using these four samples. The grinding pair consisted of pure aluminum balls with a diameter of 10 mm, and the grinding medium was a lubricating and cooling medium used in the cold rolling of aluminum sheet and strip by an aluminum industry. Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown in the figure. The results showed that the surface nano-composite combined with the pre-oxidation treatment at 150℃ for 18h was significantly better than the surface nano-composite sample, the original GCr15 combined with the roll sample pre-oxidized at 150℃ for 18h, and the original GCr15 roll sample. Its aluminum adhesion area was only 2.7% of that of the original sample, significantly improving the aluminum adhesion phenomenon.

[0028] Example 2 GCr15 rolls (aluminum processing straightening rolls) underwent surface nano-sizing treatment. The nano-sizing parameters were: rotation speed 300 rpm, feed rate 0.02 mm / r, single-pass reduction of 200 μm, and the nano-sizing tool was a 6 mm diameter YG6 cemented carbide ball. After processing, the rolls were washed and cleaned, followed by pre-oxidation treatment at 150℃ for 4 hours. For comparison, three samples were taken: the original GCr15 roll sample, the nano-sized sample, and the sample with nano-sizing combined with 4 hours of pre-oxidation treatment at 150℃. The surface hardness of the rolls after pre-oxidation treatment was consistent with that before treatment. Friction simulation tests were then conducted using these four samples. The grinding pair consisted of 10 mm diameter pure aluminum balls, and the grinding medium was a lubricating and cooling medium used in the cold rolling of aluminum sheet and strip in an aluminum industry. Figure 4 , Figure 6 and Figure 8 As shown in the figure. The results showed that the surface nano-combined sample with pre-oxidation treatment at 150℃ for 4 hours was significantly better than the surface nano-combined sample and the original GCr15 roll sample. However, its aluminum adhesion area was smaller than that of the surface nano-combined sample with pre-oxidation treatment at 150℃ for 18 hours, indicating that before the oxide layer grows to a loose state, the thicker the oxide layer, the better the anti-metal powder adhesion effect.

[0029] Example 3 GCr15 rolls (aluminum machining straightening rolls) underwent surface nano-sizing treatment. The nano-sizing parameters were: rotation speed 300 rpm, feed rate 0.02 mm / r, single-pass reduction of 200 μm, and the nano-sizing tool was a 6 mm diameter YG6 cemented carbide ball. After processing, the rolls were cleaned with water, then acid-etched for activation, followed by water washing and high-temperature alkaline oxidation at 150℃ for 5 min, generating a dense, wear-resistant, and highly adhesive pre-oxide layer. The surface hardness of the rolls after pre-oxidation treatment was consistent with that before treatment.

[0030] Comparative Example 1 GCr15 rolls (aluminum machining straightening rolls) underwent surface nano-sizing treatment. The nano-sizing parameters were: rotation speed 300 rpm, feed rate 0.02 mm / r, single-pass reduction of 200 μm, and the nano-sizing tool was a 6 mm diameter YG6 cemented carbide ball. After processing, the rolls were washed and cleaned, followed by pre-oxidation treatment at 200℃ for 2 hours. The hardness of the roll's hardened layer decreased by 40 HV, which is not conducive to long-term use.

[0031] Comparative Example 2 GCr15 rolls (aluminum machining straightening rolls) underwent surface nano-sizing treatment. The nano-sizing parameters were: rotation speed 300 rpm, feed rate 0.02 mm / r, single-pass reduction of 200 μm, and the nano-sizing cutter head was a 6 mm diameter YG6 cemented carbide ball. After processing, the rolls were cleaned with water, then acid-washed for activation, and finally subjected to high-temperature alkaline oxidation at 150℃ for 120 min. The resulting oxide layer was relatively thick, which affected the surface mechanical properties of the rolls.

[0032] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of the present invention. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A surface treatment method for preventing metal powder adhesion, characterized in that, The method includes: After surface nano-sizing treatment of the substrate, nanocrystals are formed on the surface of the substrate to obtain a substrate with surface nano-sizing; then, the substrate with surface nano-sizing is subjected to thermal oxidation treatment or chemical oxidation treatment to form a pre-oxidation layer on the nanocrystals to obtain a substrate with resistance to metal powder adhesion.

2. The surface treatment method for preventing metal powder adhesion according to claim 1, characterized in that, The thermal oxidation treatment includes: tempering the nano-sized substrate at a tempering temperature for 0.5-20 h under atmospheric conditions.

3. The surface treatment method for preventing metal powder adhesion according to claim 1, characterized in that, The thermal oxidation treatment includes: pre-oxidizing the substrate after surface nano-sizing; wherein the oxygen partial pressure of the pre-oxidation treatment is adapted to the material of the substrate, and the temperature of the pre-oxidation treatment does not exceed the tempering temperature of the substrate.

4. The surface treatment method for preventing metal dust adhesion according to claim 1, characterized in that, The chemical oxidation treatment includes: subjecting the nano-sized substrate to alkaline oxidation at 135-155°C for 1-20 min; preferably, before the alkaline oxidation treatment, the nano-sized substrate is subjected to surface cleaning, acid pickling activation and water washing treatment in sequence.

5. The surface treatment method for preventing metal powder adhesion according to claim 1, characterized in that, Between surface nano-sizing treatment and thermal or chemical oxidation treatment, the following is also included: The nano-sized substrate is processed by grinding to meet the requirements for machine use. The substrate with the nano-sized surface is then cleaned to ensure that the surface of the nano-sized substrate is free of dust and oil.

6. The surface treatment method for preventing metal dust adhesion according to claim 1 or 5, characterized in that, The surface nanoforming treatment includes: using a surface nanoforming machine or CNC lathe to perform surface nanoforming treatment on the substrate, specifically surface mechanical grinding technology, surface mechanical rolling technology or surface mechanical rolling technology, so that nanocrystals are formed on the surface of the substrate.

7. A substrate with resistance to metal dust adhesion, characterized in that, The substrate with anti-metal dust adhesion includes a body, nanocrystals formed on the surface of the body, and a pre-oxidized layer formed on the nanocrystals; The substrate is made of metal, and the pre-oxidized layer is a metal oxide layer with a thickness of 1-100 nm.

8. The substrate with anti-metal dust adhesion according to claim 7, characterized in that, The nanocrystalline layer is obtained by surface nano-sizing of the substrate, and the pre-oxidized layer is obtained by further thermal oxidation or chemical oxidation of the substrate.

9. The application of a substrate with anti-metal dust adhesion as described in claim 7 or 8 in the field of metal sheet and strip rolling.

10. The application according to claim 9, characterized in that, The metal sheet and strip rolling process includes aluminum processing, copper processing, and galvanized sheet processing.

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