A method for cleaning the surface of a steel workpiece of mill scale

Abstract

The application discloses a method for cleaning oil sludge on the surface of a steel workpiece, and belongs to the field of heat treatment and surface treatment. The method comprises the following steps: placing the workpiece to be cleaned into a deep cooling box, and fully cooling the workpiece at-160 DEG C to-140 DEG C; hoisting the fully cooled workpiece out of the deep cooling box, and keeping the workpiece in a moving state in the air for 3-5 min, so that the frost on the surface of the workpiece is uniformly distributed, and then placing the workpiece into a water displacement medium tank; immersing the workpiece into water displacement medium with a temperature of 25 DEG C plus or minus 5 DEG C, and keeping the workpiece in the water displacement medium for 1.9-2.1 min, then oscillating the workpiece up and down for 9-11 times, and then keeping the workpiece in the water displacement medium for 9-11 min. The application is applied to the cleaning of oil sludge on the surface of a steel workpiece, solves the technical problem that the existing surface cleaning technology still has poor cleaning effect when used for cleaning oil sludge on the surface of a steel workpiece, and can effectively remove oil, inorganic salt, adhered carbon black dust, iron filings and other sundries on the surface of the workpiece.

Description

Technical Field

[0001] This invention belongs to the field of heat treatment and surface treatment, and particularly relates to a method for cleaning sludge from the surface of steel workpieces. Background Technology

[0002] Surface modification technology, a commonly used technique in the heat treatment industry, is widely applied in the machining and manufacturing sector. Before heat treatment, workpieces may undergo processes such as forging, grinding, turning, rust prevention, and polishing. These processes utilize forging lubricants, cutting fluids, cutting oils, grinding fluids, grinding oils, rust inhibitors, rust-preventive oils, polishing agents, and even particulate substances like graphite powder and shaping agents. Before heat treatment, these substances can form a visible layer of sludge or an invisible protective film on the workpiece surface. Some of these substances may even react at high temperatures, hindering subsequent surface modification treatments such as carburizing or nitriding. Furthermore, as the machinery industry increasingly demands high-quality workpieces with attractive appearances, customers desire products with aesthetically pleasing designs. The aforementioned substances can make the product appear unsightly, increasing subsequent processing costs and potentially failing to achieve the desired results. Therefore, cleaning the sludge or oil film from the workpiece surface is crucial before heat treatment.

[0003] Currently, commonly used surface cleaning technologies include those relying on dissolution, adsorption, and displacement; those relying on physical methods; and those relying on high-temperature laser cleaning. Dissolution, adsorption, and displacement methods include water-based cleaning, hydrocarbon cleaning, organic solvent cleaning, acid washing, alkaline washing, and electropolishing. Physical methods include sandblasting, shot blasting, and wiping. Each of these technologies has its advantages and plays different roles in various industries. However, when used to remove sludge from steel workpieces, these surface cleaning technologies still suffer from unsatisfactory cleaning results. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to overcome the technical problem that the existing surface cleaning technology still has poor cleaning effect when cleaning oil sludge on the surface of steel workpieces. The present invention proposes a new method for cleaning oil sludge on the surface of steel workpieces that can effectively remove oil, inorganic salts, adhering carbon black, dust, iron filings and other impurities from the workpiece surface.

[0005] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows:

[0006] This invention provides a method for cleaning sludge from the surface of steel workpieces, comprising a cryogenic treatment step, a transfer step, and a water replacement step.

[0007] The cryogenic treatment step includes: placing the workpiece to be cleaned into a cryogenic chamber and cooling it fully at -160°C to -140°C;

[0008] The transfer step includes: lifting the fully cooled workpiece out of the cryogenic chamber and keeping it in the air for 3-5 minutes. During the period of keeping it in the air, the workpiece is kept in a moving state so that the white frost on the surface of the workpiece is evenly distributed. Then the workpiece is placed in the water replacement medium tank.

[0009] The water replacement step includes: immersing the workpiece in a water replacement medium at a temperature of 25℃±5℃, and after standing in the water replacement medium for 1.9-2.1 minutes, swinging the workpiece up and down 9-11 times, and then standing in the water replacement medium for 9-11 minutes.

[0010] Preferably, the cryogenic chamber uses liquid nitrogen for cooling, and in the cryogenic treatment step, the workpiece to be cleaned continues to be cooled at -150°C for at least 2 hours after the temperature of the workpiece to be cleaned reaches -150°C.

[0011] Preferably, the temperature of the air in the transfer step is -10 to 20°C.

[0012] Preferably, the water replacement medium is an organic solvent. After the workpiece passes through the water replacement step, the water formed by the frost on the workpiece in the transfer step becomes liquid water after entering the water replacement medium. The water replacement medium surrounds the water and the oil sludge and dirt encapsulated by the water, and causes the water and the oil sludge and dirt encapsulated by the water to flow into the bottom of the water replacement medium tank under the action of gravity.

[0013] Preferably, the process also includes a cleaning step following the water displacement step, wherein the cleaning step further includes cleaning the workpiece with a hydrocarbon cleaner within 10 minutes after the water displacement step to remove the water displacement medium adhering to the surface.

[0014] Preferably, it also includes tooling for fixing the workpiece, the tooling including a support frame and a stainless steel mesh connected to the connecting support frame.

[0015] Preferably, the tooling is rectangular with dimensions of 1.2m * 0.6m * 0.6m.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] This invention provides a method for cleaning sludge from the surface of steel workpieces. It employs a combination of cryogenic technology-assisted water replacement and hydrocarbon cleaning technology to clean the workpieces. No water-based media are involved, making it environmentally friendly, pollution-free, and wastewater-free. This method effectively cleans sludge formed on the workpiece surface without the need for external forces such as wiping, vibration, or ultrasonic cleaning. It can remove oil films invisible to the naked eye, especially those formed by rust-preventive oil, demonstrating excellent cleaning performance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the water replacement medium tank provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the surface of a gray iron workpiece before cleaning, provided in an embodiment of the present invention.

[0020] Figure 3 for Figure 2 A schematic diagram of the workpiece surface after cleaning;

[0021] Figure 4 A schematic diagram of the appearance of a workpiece after nitriding following hydrocarbon cleaning.

[0022] Figure 5 A schematic diagram of the appearance of the nitrided product after cleaning by the method of the present invention;

[0023] Figure 6 This is a schematic diagram of the tooling provided in an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions in specific embodiments of the present invention will now be described in detail and completely with reference to the accompanying drawings. Obviously, the described embodiments are merely some specific implementations of the overall technical solution of the present invention, and not all implementations. Based on the overall concept of the present invention, all other embodiments obtained by those skilled in the art fall within the protection scope of the present invention.

[0025] This invention provides a method for cleaning sludge from the surface of steel workpieces, comprising a cryogenic treatment step, a transfer step, and a water replacement step. This method uses a combination of cryogenic technology assisted by water replacement and hydrocarbon cleaning technology to clean the workpiece. No water-based media are involved, making it environmentally friendly and pollution-free, with no wastewater discharge. It has a good cleaning effect on sludge formed on the workpiece surface, removing contaminants without the need for external forces such as wiping, vibration, or ultrasonic cleaning. It can remove oil films invisible to the naked eye on the workpiece surface, especially those formed by rust-preventive oil, exhibiting excellent cleaning performance.

[0026] The cryogenic treatment step includes: placing the workpiece to be cleaned into a cryogenic chamber at -160°C to -140°C.

[0027] Sufficient cooling at -150°C is preferred. In a preferred embodiment, the cryogenic chamber uses liquid nitrogen for cooling. During the cryogenic treatment step, the workpiece to be cleaned continues to be cooled at -160°C to -140°C (preferably -150°C) for at least 2 hours after the workpiece temperature reaches -160°C to -140°C (preferably -150°C) to ensure that the workpiece surface temperature reaches -150°C. The cryogenic chamber uses liquid nitrogen for cooling, and the minimum temperature can reach -196°C. When performing cryogenic treatment on the workpiece, the temperature of the cryogenic chamber is set to -150°C.

[0028] The transfer step includes: lifting the fully cooled workpiece out of the cryogenic chamber and allowing it to remain in the air for 3-5 minutes, ensuring the workpiece is in a moving state during this time to ensure even distribution of frost on its surface before placing it in a water replacement medium tank. In a preferred embodiment, the air temperature during the transfer step is -10 to 20°C. It should be noted that the transfer process from the cryogenic chamber to the water replacement medium significantly affects the treatment effect on the oil sludge on the workpiece surface. Specifically, the ambient temperature and dwell time have a significant impact on the frost thickness, and the movement method also significantly affects the frost thickness of the workpieces inside and outside the frame, potentially leading to insufficient frost thickness on the inner workpiece, thus affecting the subsequent dehydration effect. Therefore, the dwell time, transfer operation, and air temperature are specifically limited in the transfer step.

[0029] The water replacement step includes: immersing the workpiece in a water replacement medium at a temperature of 25℃±5℃, and allowing it to stand in the water replacement medium for 1.9-2.1 minutes (preferably 2 minutes), then swinging the workpiece up and down 9-11 times (preferably 10 times), and then allowing it to stand in the water replacement medium for 9-11 minutes (preferably 10 minutes). In a preferred embodiment, the water replacement medium is an organic solvent, specifically a rapidly dehydrating organic solvent. After the water replacement step, the water formed by frost on the workpiece during the transfer step becomes liquid water upon entering the water replacement medium. The water replacement medium surrounds the water and the oil sludge encapsulated by the water, and the water and the oil sludge encapsulated by the water flow into the bottom of the water replacement medium tank under gravity, thereby achieving the effect of cleaning the oil sludge on the surface of the workpiece. The structure of the water replacement medium tank is as follows: Figure 1As shown, due to the different shapes of the workpieces, after standing for 2 minutes, the water replacement medium has cleaned most of the oil stains wrapped in water to the bottom of the medium tank. However, some flat areas still cannot flow away. Therefore, the up-and-down swinging method is used to completely remove the oil stains from the workpiece surface. Then, it is left to stand, so that the oil stains wrapped in water accumulate at the bottom of the tank and remain there. The water replacement medium is completely separated from the water. After standing, the bottom of the tank is water and sludge, and the upper layer is the water replacement medium. The boundary is clear and there is no interference. The water replacement medium can continue to be used without affecting its performance. The bottom of the tank should be emptied periodically to remove the water and sludge to ensure the cleanliness of the tank.

[0030] Existing workpiece cleaning methods include sandblasting, shot peening, manual cleaning, and laser cleaning. However, sandblasting increases workpiece roughness and fails to completely remove the anti-rust oil film; shot peening also increases roughness, prevents dust removal, and makes cleaning difficult when there is a lot of grease; manual cleaning is time-consuming, labor-intensive, and extremely costly; laser cleaning has difficulties in treating holes. This invention uses ultra-low temperature cooling to solidify oil stains on the workpiece surface, allowing them to quickly move into the water replacement medium and rapidly detach from the workpiece surface. After ultra-low temperature cooling, moisture in the air adheres to the workpiece surface, forming a white frost that evenly covers the surface, facilitating the water replacement medium to fully replace the moisture and the water-encapsulated dirt, which then flows to the bottom of the water replacement tank. After water replacement, some grease remains on the workpiece surface, requiring vacuum cleaning within a short time to prevent the grease from solidifying after the water replacement medium evaporates, thus reducing the effectiveness of vacuum cleaning. Images of the workpiece before and after cleaning using this invention are shown below. Figure 2 , 3 As shown in Figures 4 and 5.

[0031] In a preferred embodiment, the process further includes a cleaning step following the water replacement step. The cleaning step further includes cleaning the workpiece using a hydrocarbon cleaner within 10 minutes after the water replacement step to remove the water replacement medium adhering to its surface. After the workpiece is removed from the water replacement medium, a layer of oily water replacement medium covers its surface, requiring removal. Therefore, it needs to be cleaned using a hydrocarbon cleaner within 10 minutes to remove the adhering water replacement medium.

[0032] In a preferred embodiment, it further includes tooling for fixing the workpiece, such as... Figure 6As shown, the fixture includes a support frame and a stainless steel mesh connected to the support frame. Further, the fixture is rectangular, with dimensions of 1.2m * 0.6m * 0.6m. Specifically, a workpiece containing sludge and various contaminants is placed inside this rectangular fixture, which, except for the main support frame which is a steel column, is surrounded by 304 stainless steel mesh. The workpiece undergoes a series of cleaning steps within the fixture, including cryogenic treatment, transfer, water replacement, and washing.

[0033] To provide a clearer and more detailed description of the method for cleaning sludge from the surface of steel workpieces provided in the embodiments of the present invention, specific embodiments will be described below.

[0034] Example 1

[0035] 1) Place the workpiece containing sludge and various contaminants into the tooling;

[0036] 2) Place the tooling and the workpiece to be cleaned into the cryogenic chamber, set the temperature of the cryogenic chamber to -150℃, and keep it at -150℃ for 2 hours to ensure that the surface temperature of the workpiece reaches -150℃.

[0037] 3) Lift the cryogenically cooled workpiece and tooling out of the cryogenic chamber and leave them in the air for 5 minutes. During this time, ensure that the workpiece is in a vertical moving state and that the white frost on the workpiece surface is evenly and completely distributed. The air temperature is -10℃.

[0038] 4) Place the workpiece in a dedicated water replacement medium tank, ensuring that the water replacement medium level is higher than the workpiece. The water replacement medium temperature is 25℃±5℃. After standing in the medium tank for 2 minutes, swing the workpiece up and down 10 times, then let it stand for 10 minutes.

[0039] 5) After the workpiece and tooling are lifted out of the water replacement medium, they should be cleaned with a hydrocarbon cleaning machine within 10 minutes to remove the water replacement medium adhering to the surface.

[0040] Example 2

[0041] 1) Place the workpiece containing sludge and various contaminants into the tooling;

[0042] 2) Place the tooling and the workpiece to be cleaned into the cryogenic chamber, set the temperature of the cryogenic chamber to -150℃, and keep it at -150℃ for 2 hours to ensure that the surface temperature of the workpiece reaches -150℃.

[0043] 3) Lift the cryogenically cooled workpiece and tooling out of the cryogenic chamber and leave them in the air for 5 minutes. During this time, ensure that the workpiece is in a back-and-forth moving state and that the white frost on the workpiece surface is evenly and completely distributed. The air temperature is -10℃.

[0044] 4) Place the workpiece in a dedicated water replacement medium tank, ensuring that the water replacement medium level is higher than the workpiece. The water replacement medium temperature is 25℃±5℃. After standing in the medium tank for 2 minutes, swing the workpiece up and down 10 times, then let it stand for 10 minutes.

[0045] 5) After the workpiece and tooling are lifted out of the water replacement medium, they should be cleaned with a hydrocarbon cleaning machine within 10 minutes to remove the water replacement medium adhering to the surface.

[0046] Example 3

[0047] 1) Place the workpiece containing sludge and various contaminants into the tooling;

[0048] 2) Place the tooling and the workpiece to be cleaned into the cryogenic chamber, set the temperature of the cryogenic chamber to -150℃, and keep it at -150℃ for 2 hours to ensure that the surface temperature of the workpiece reaches -150℃.

[0049] 3) Lift the cryogenically cooled workpiece and tooling out of the cryogenic chamber and leave them in the air for 5 minutes. During this time, ensure that the workpiece is in a vertical moving state and that the white frost on the workpiece surface is evenly and completely distributed. The air temperature is 0℃.

[0050] 4) Place the workpiece in a dedicated water replacement medium tank, ensuring that the water replacement medium level is higher than the workpiece. The water replacement medium temperature is 25℃±5℃. After standing in the medium tank for 2 minutes, swing the workpiece up and down 10 times, then let it stand for 10 minutes.

[0051] 5) After the workpiece and tooling are lifted out of the water replacement medium, they should be cleaned with a hydrocarbon cleaning machine within 10 minutes to remove the water replacement medium adhering to the surface.

[0052] Example 4

[0053] 1) Place the workpiece containing sludge and various contaminants into the tooling;

[0054] 2) Place the tooling and the workpiece to be cleaned into the cryogenic chamber, set the temperature of the cryogenic chamber to -150℃, and keep it at -150℃ for 2 hours to ensure that the surface temperature of the workpiece reaches -150℃.

[0055] 3) Lift the cryogenically cooled workpiece and tooling out of the cryogenic chamber and leave them in the air for 5 minutes. During this time, ensure that the workpiece is in a vertical moving state and that the white frost on the workpiece surface is evenly and completely distributed. The air temperature is 10℃.

[0056] 4) Place the workpiece in a dedicated water replacement medium tank, ensuring that the water replacement medium level is higher than the workpiece. The water replacement medium temperature is 25℃±5℃. After standing in the medium tank for 2 minutes, swing the workpiece up and down 10 times, then let it stand for 10 minutes.

[0057] 5) After the workpiece and tooling are lifted out of the water replacement medium, they should be cleaned with a hydrocarbon cleaning machine within 10 minutes to remove the water replacement medium adhering to the surface.

[0058] Example 5

[0059] 1) Place the workpiece containing sludge and various contaminants into the tooling;

[0060] 2) Place the tooling and the workpiece to be cleaned into the cryogenic chamber, set the temperature of the cryogenic chamber to -150℃, and keep it at -150℃ for 2 hours to ensure that the surface temperature of the workpiece reaches -150℃.

[0061] 3) Lift the cryogenically cooled workpiece and tooling out of the cryogenic chamber and leave them in the air for 5 minutes. During this time, ensure that the workpiece is in a vertical moving state and that the white frost on the workpiece surface is evenly and completely distributed. The air temperature is 20℃.

[0062] 4) Place the workpiece in a dedicated water replacement medium tank, ensuring that the water replacement medium level is higher than the workpiece. The water replacement medium temperature is 25℃±5℃. After standing in the medium tank for 2 minutes, swing the workpiece up and down 10 times, then let it stand for 10 minutes.

[0063] 5) After the workpiece and tooling are lifted out of the water replacement medium, they should be cleaned with a hydrocarbon cleaning machine within 10 minutes to remove the water replacement medium adhering to the surface.

[0064] Comparative Example 1

[0065] 1) Place the workpiece containing sludge and various contaminants into the tooling;

[0066] 2) Place the tooling and the workpiece to be cleaned into the cryogenic chamber, set the temperature of the cryogenic chamber to -150℃, and keep it at -150℃ for 2 hours to ensure that the surface temperature of the workpiece reaches -150℃.

[0067] 3) Lift the cryogenically cooled workpiece and tooling out of the cryogenic chamber and leave them in the air for 2 minutes. During this time, ensure that the workpiece is in a vertical moving state and that the center of the workpiece is not covered with frost. The air temperature is -10℃.

[0068] 4) Place the workpiece in a dedicated water replacement medium tank, ensuring that the water replacement medium level is higher than the workpiece. The water replacement medium temperature is 25℃±5℃. After standing in the medium tank for 2 minutes, swing the workpiece up and down 10 times, then let it stand for 10 minutes.

[0069] 5) After the workpiece and tooling are lifted out of the water replacement medium, they should be cleaned with a hydrocarbon cleaning machine within 10 minutes to remove the water replacement medium adhering to the surface.

[0070] Comparative Example 2

[0071] 1) Place the workpiece containing sludge and various contaminants into the tooling;

[0072] 2) Place the tooling and the workpiece to be cleaned into the cryogenic chamber, set the temperature of the cryogenic chamber to -150℃, and keep it at -150℃ for 2 hours to ensure that the surface temperature of the workpiece reaches -150℃.

[0073] 3) Lift the cryogenically cooled workpiece and tooling out of the cryogenic chamber and leave them in the air for 6 minutes. During this time, ensure that the workpiece is in a vertical moving state and that the white frost on the workpiece surface is evenly and completely distributed. The air temperature is -10℃.

[0074] 4) Place the workpiece in a dedicated water replacement medium tank, ensuring that the water replacement medium level is higher than the workpiece. The water replacement medium temperature is 25℃±5℃. After standing in the medium tank for 2 minutes, swing the workpiece up and down 10 times, then let it stand for 10 minutes.

[0075] 5) After the workpiece and tooling are lifted out of the water replacement medium, they should be cleaned with a hydrocarbon cleaning machine within 10 minutes to remove the water replacement medium adhering to the surface.

[0076] Comparative Example 3

[0077] 1) Place the workpiece containing sludge and various contaminants into the tooling;

[0078] 2) Place the tooling and the workpiece to be cleaned into the cryogenic chamber, set the temperature of the cryogenic chamber to -150℃, and keep it at -150℃ for 2 hours to ensure that the surface temperature of the workpiece reaches -150℃.

[0079] 3) Lift the cryogenically cooled workpiece and tooling out of the cryogenic chamber and leave them in the air for 5 minutes. During this time, ensure that the workpiece remains stationary and that the center of the workpiece is not covered with frost. The air temperature is -10℃.

[0080] 4) Place the workpiece in a dedicated water replacement medium tank, ensuring that the water replacement medium level is higher than the workpiece. The water replacement medium temperature is 25℃±5℃. After standing in the medium tank for 2 minutes, swing the workpiece up and down 10 times, then let it stand for 10 minutes.

[0081] 5) After the workpiece and tooling are lifted out of the water replacement medium, they should be cleaned with a hydrocarbon cleaning machine within 10 minutes to remove the water replacement medium adhering to the surface.

[0082] Comparative Example 4

[0083] 1) Place the workpiece containing sludge and various contaminants into the tooling;

[0084] 2) Place the tooling and the workpiece to be cleaned into the cryogenic chamber, set the temperature of the cryogenic chamber to -150℃, and keep it at -150℃ for 2 hours to ensure that the surface temperature of the workpiece reaches -150℃.

[0085] 3) Lift the cryogenically cooled workpiece and tooling out of the cryogenic chamber and leave them in the air for 5 minutes. During this time, ensure that the workpiece is in a vertical moving state and that the white frost on the workpiece surface is evenly and completely distributed. The air temperature is -10℃.

[0086] 4) Place the workpiece in a dedicated water replacement medium tank, ensuring that the water replacement medium level is higher than the workpiece. The water replacement medium temperature is 25℃±5℃. Let it stand in the medium tank for 12 minutes.

[0087] 5) After the workpiece and tooling are lifted out of the water replacement medium, they should be cleaned with a hydrocarbon cleaning machine within 10 minutes to remove the water replacement medium adhering to the surface.

[0088] Cleaning effect

[0089] The cleaning effects of the workpieces in Examples 1-5 and Comparative Examples 1-4 are shown in Table 1.

[0090] Table 1. Cleaning effect of the workpieces in Examples 1-5 and Comparative Examples 1-4

[0091]

[0092]

Claims

1. A method for cleaning sludge from the surface of steel workpieces, characterized in that, The process includes, in sequence, a cryogenic treatment step, a transfer step, and a water replacement step; The cryogenic treatment step includes: placing the workpiece to be cleaned into a cryogenic chamber and cooling it fully at -160°C to -140°C; The transfer step includes: lifting the fully cooled workpiece out of the cryogenic chamber and keeping it in the air for 3-5 minutes. During the period of keeping it in the air, the workpiece is kept in a moving state so that the white frost on the surface of the workpiece is evenly distributed. Then the workpiece is placed in the water replacement medium tank. The water replacement step includes: immersing the workpiece in a water replacement medium at a temperature of 25℃±5℃, and after standing in the water replacement medium for 1.9-2.1 min, swinging the workpiece up and down 9-11 times, and then standing in the water replacement medium for 9-11 min. The air temperature during the transfer step is -10 to 20°C; The water replacement medium is an organic solvent. After the workpiece passes through the water replacement step, the water formed by the frost on the workpiece in the transfer step becomes liquid water after entering the water replacement medium. The water replacement medium surrounds the water and the oil sludge and dirt wrapped in the water, and causes the water and the oil sludge and dirt wrapped in the water to flow into the bottom of the water replacement medium tank under the action of gravity.

2. The method for cleaning sludge from the surface of steel workpieces according to claim 1, characterized in that, The cryogenic chamber uses liquid nitrogen for cooling, and in the cryogenic treatment step, the workpiece to be cleaned continues to be cooled at -150°C for at least 2 hours after the temperature of the workpiece to be cleaned reaches -150°C.

3. The method for cleaning sludge from the surface of steel workpieces according to claim 1, characterized in that, It also includes a cleaning step after the water replacement step, the cleaning step further including: cleaning the workpiece with a hydrocarbon cleaner within 10 minutes after the water replacement step to remove the water replacement medium adhering to the surface.

4. The method for cleaning sludge from the surface of steel workpieces according to claim 1, characterized in that, It also includes tooling for fixing the workpiece, the tooling including a support frame and a stainless steel mesh connected to the support frame.

5. The method for cleaning sludge from the surface of steel workpieces according to claim 4, characterized in that, The tooling is rectangular, with dimensions of 1.2 m * 0.6 m * 0.6 m.

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