Steel surface treatment technology and application thereof

Abstract

The invention provides a steel surface treatment technology and application thereof. The steel surface treatment technology comprises the steps that to-be-treated strip steel is subjected to brush roll treatment and pulpifying and polishing treatment, and to-be-pickled strip steel is obtained; wherein the to-be-treated strip steel comprises stainless steel and common steel; the to-be-pickled strip steel is subjected to pickling to obtain the product strip steel, and pickling comprises the steps that the to-be-pickled strip steel is immersed in a pickling solution, the pickling solution comprises hydrochloric acid and sodium phosphate, the concentration of the hydrochloric acid is 150-200 g / l, and the concentration of the sodium phosphate is 3-5%. Compatible treatment of common steel and stainless steel is achieved, the steel oxide layer is thoroughly removed, and meanwhile the steel surface integrity and the structure stability are guaranteed to the maximum extent.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a steel surface treatment technology and application thereof. Background Art

[0002] With the rapid development of the national economy and the improvement of people's environmental awareness, stainless steel with excellent comprehensive performance, as a green and environmentally friendly material, has been widely used in important fields related to national economy and people's livelihood, such as petrochemical, aerospace and energy. However, stainless steel must be subjected to heat treatment in the production process. The oxide layer produced by heat treatment not only destroys the aesthetics of the stainless steel surface, but also affects the subsequent processing and use of the stainless steel material. Therefore, the oxide layer on the surface of stainless steel must be removed before subsequent processing.

[0003] At present, the commonly used technology is to use sulfuric acid + mixed acid (nitric acid + hydrofluoric acid) pickling production line to remove the oxide layer on the surface of stainless steel. However, this common technology cannot be applied to the removal of the oxide layer on the surface of ordinary steel. The reason is that ordinary steel has poor corrosion resistance and its organizational structure is not stable enough, while the strong acid production line of sulfuric acid plus mixed acid is highly corrosive. Applying strong acid to the surface treatment of ordinary steel can easily cause surface damage and quality degradation of ordinary steel, thus affecting subsequent applications.

[0004] In common technology, ordinary steel often uses traditional hydrochloric acid pickling production lines to remove the oxide layer on the surface of stainless steel. When the traditional hydrochloric acid pickling production line is applied to the surface treatment of stainless steel, the hydrochloric acid often reacts incompletely or insufficiently, resulting in partial residue of the oxide layer; or the chloride generated by the alloy elements and chloride ions in the stainless steel cannot be completely dissolved in hydrochloric acid, resulting in the residue of the oxide layer. It can be seen that the production efficiency of hydrochloric acid is relatively low when it is applied to the surface treatment of stainless steel, and considering the treatment effect, putting large quantities of hydrochloric acid into use means extremely high production costs and high practical difficulty. Based on the above, it is urgent to develop a steel surface treatment technology and its application to solve or at least alleviate the above-mentioned technical problem of not being able to take into account both ordinary steel and stainless steel surface treatment at the same time. Summary of the invention

[0005] In order to solve the technical problem that the above-mentioned related technologies cannot take into account the surface treatment of both ordinary steel and stainless steel, the present invention provides a steel surface treatment technology, comprising the steps of:

[0006] The strip steel to be processed is subjected to brush roller processing and slurry grinding processing to obtain the strip steel to be pickled; wherein the strip steel to be processed includes stainless steel and ordinary steel;

[0007] The steel strip to be pickled is pickled to obtain a product steel strip, and the pickling comprises the steps of: immersing the steel strip to be pickled in a pickling solution, the pickling solution comprises hydrochloric acid and sodium phosphate, the concentration of the hydrochloric acid is 150-200g / l, and the concentration of the sodium phosphate is 3-5%.

[0008] Furthermore, the brush roll treatment includes rough brushing treatment and fine brushing treatment. The brush filaments in the rough brushing treatment include nylon filaments containing silicon carbide abrasive, the size of the brush filaments in the rough brushing treatment is 1.5 - 1.7 mm, the brush filaments in the fine brushing treatment include nylon filaments containing micropowder silicon carbide abrasive, and the size of the brush filaments in the fine brushing treatment is 0.2 - 0.4 mm.

[0009] Furthermore, the pulping and grinding treatment includes the steps of: a nozzle spraying mortar abrasive onto the strip to be treated after the brush roll treatment to achieve physical grinding, wherein the throwing speed of the mortar abrasive is 150 m / s - 250 m / s.

[0010] Furthermore, the jet density of the mortar abrasive is 3000 kg / m 3 - 3100 kg / m 3 , and the vertical height from the nozzle to the strip to be treated after the brush roll treatment is 90 mm - 110 mm.

[0011] Furthermore, the material of the mortar abrasive includes steel sand, the Vickers hardness of the mortar abrasive is 600 - 1000 kg / mm 2 , the particle size of the mortar abrasive is 100 - 200 mesh; the shape of the mortar abrasive is small angular type.

[0012] Furthermore, during the pickling process, the moving speed of the strip to be pickled is 70 m / min - 90 m / min.

[0013] Furthermore, the fan angle of the nozzle is 55° - 65°, the scattering angle of the nozzle is 25° - 35°, the diameter of the nozzle is 1.3 mm - 1.6 mm, the outlet pressure of the nozzle is 60 MPa - 70 MPa, and the incident angle of the mortar abrasive projected onto the steel strip is 60° - 70°.

[0014] Furthermore, the strip to be pickled is pickled to obtain a product strip, which further includes the step of: the pickled strip is subjected to skin pass treatment to obtain the product strip; wherein, the elongation of the skin pass treatment is not more than 2%.

[0015] Furthermore, the skin pass treatment includes four-high small rolling treatment, and in the four-high small rolling treatment, the diameter of the backup roll is 500 - 600 mm, and the diameter of the work roll is 250 - 300 mm.

[0016] The present invention provides an application of the steel surface treatment method as described in any one of the above in the removal of oxide layers on the surfaces of stainless steel and carbon steel.

[0017] Compared with the prior art, the present invention has at least the following advantages:

[0018] The present invention provides a steel surface treatment technology, which mainly includes the following steps: brush roll treatment - slurry grinding treatment - pickling treatment. First, the Fe2O3 layer and Fe3O4 layer on the outer layer of FeO scale are removed through surface brush roll treatment, and at the same time, the FeO and lean Cr layers are descaled. Then, the FeO and lean Cr layers are removed through the mortar grinding treatment technology. Finally, the treated strip steel surface is cleaned through hydrochloric acid pickling and sodium phosphate rinsing, achieving the complete removal of the oxide layer on the strip steel surface to be treated.

[0019] The pickling solution used in the pickling treatment of the present invention includes hydrochloric acid with a concentration of 180 g / l and sodium phosphate with a concentration of 3% - 5%. Among them, hydrochloric acid can dissolve iron oxide and other metal element oxides, and sodium phosphate is a salt of a strong base and a weak acid, which hydrolyzes in water to be alkaline. When sodium phosphate and hydrochloric acid are used in combination, a synergistic effect is produced, enhancing the pickling effect. At the same concentration, the acidity of the pickling solution used in the present invention is lower than that of the pickling solution used in the conventional technology for treating stainless steel. Combining with the foregoing brush roll treatment and mortar grinding treatment, the compatible treatment of plain steel and stainless steel is realized, and while completely removing the steel oxide layer, the integrity of the steel surface and the tissue stability are guaranteed to the greatest extent. Brief Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0021] Figure 1 It is a physical diagram of the sample in Embodiment 1 of the present invention.

[0022] Figure 2 It is a metallographic diagram of the oxide layer of Sample No. 5 in Embodiment 1 of the present invention under 200 times magnification.

[0023] Figure 3 It is a metallographic diagram of the oxide layer of Sample No. 5 in Embodiment 1 of the present invention under 200 times magnification.

[0024] Figure 4 It is a schematic diagram of the oxygen element distribution intensity of Sample No. 5 in Embodiment 1 of the present invention.

[0025] Figure 5 It is a schematic diagram of the oxygen element distribution intensity of Sample No. 5 in Embodiment 1 of the present invention.

[0026] Figure 6 It is a metallographic structure diagram of the oxide layer of Sample No. 1 in Embodiment 1 of the present invention under 200 times magnification.

[0027] Figure 7Schematic diagram of the oxygen element distribution intensity of Sample No. 1 in Embodiment 1 of the present invention.

[0028] Figure 8 Schematic diagram of the oxygen element distribution intensity of Sample No. 1 in Embodiment 1 of the present invention.

[0029] Figure 9 Schematic diagram of the oxygen element distribution intensity of Sample No. 3 in Embodiment 1 of the present invention.

[0030] Figure 10 Schematic diagram of the oxygen element distribution intensity of Sample No. 3 in Embodiment 1 of the present invention.

[0031] Figure 11 Metallographic diagram of Sample No. 2 at 200 times in Comparative Example 1 of the present invention.

[0032] Figure 12 Schematic diagram of the oxygen element distribution intensity of Sample No. 2 in Comparative Example 1 of the present invention.

[0033] Figure 13 Schematic diagram of the oxygen element distribution intensity of Sample No. 2 in Comparative Example 1 of the present invention.

[0034] Figure 14 Schematic diagram of the oxygen element distribution intensity of Sample No. 4 in Comparative Example 1 of the present invention.

[0035] Figure 15 Schematic diagram of the oxygen element distribution intensity of Sample No. 4 in Comparative Example 1 of the present invention.

[0036] Figure 16 Surface energy spectrum analysis diagram of Sample No. 5 in Embodiment 1 of the present invention.

[0037] Figure 17 Surface energy spectrum analysis diagram of Sample No. 1 in Embodiment 1 of the present invention.

[0038] Figure 18 Surface energy spectrum analysis diagram of Sample No. 4 in Comparative Example 1 of the present invention. Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0040] Moreover, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions conflicts with each other or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0041] When numerical ranges are given in the embodiments, it should be understood that unless otherwise specified in the present invention, either endpoint of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention, based on the understanding of those skilled in the art of the present technology field of the prior art and the description of the present invention, any method, device, and material of the prior art similar or equivalent to those described in the embodiments of the present invention can also be used to implement the present invention.

[0042] The present invention provides a steel surface treatment technology, including the steps:

[0043] S1. The strip to be processed is subjected to brush roll treatment and slurry grinding treatment to obtain the strip to be pickled; wherein, the strip to be processed includes stainless steel and common steel.

[0044] In some embodiments, the brush roll treatment includes rough brush treatment and fine brush treatment. The brush filaments in the rough brush treatment include nylon filaments containing silicon carbide abrasive, with a size of 1.5 - 1.7 mm, and the brush filaments in the fine brush treatment include nylon filaments containing micro powder silicon carbide abrasive, with a size of 0.2 - 0.4 mm.

[0045] Specifically, the strip to be processed moves through the brush roll device, successively undergoing rough brush treatment and fine brush treatment.

[0046] In some embodiments, the slurry grinding treatment includes shot blasting treatment, which may include the steps: the nozzle sprays the mortar abrasive onto the strip to be processed after the brush roll treatment to achieve physical grinding. Among them, the throwing speed of the mortar abrasive can be 150 m / s - 250 m / s, the jet density of the mortar abrasive can be 3000 kg / m 3 ~3100 kg / m 3 , and the vertical height from the nozzle to the strip to be processed after the brush roll treatment can be 90 mm - 110 mm.

[0047] The material of the mortar abrasive can include steel sand, the Vickers hardness of the mortar abrasive can be 800 kg / mm 2 , the particle size of the mortar abrasive can be 150; the shape of the mortar abrasive can be small angular type.

[0048] Furthermore, the fan angle of the nozzle is 55° - 65°, the scattering angle of the nozzle is 25° - 35°, the diameter of the nozzle is 1.3 mm - 1.6 mm, the outlet pressure of the nozzle is 60 MPa - 70 MPa, and the incident angle of the mortar abrasive projected onto the steel strip is 60° - 70°.

[0049] After the brush roll treatment, the strip is thinned significantly over a large area, while locally remaining at the original thickness. After the slurry grinding treatment, the oxide layer is basically removed, but there is still an oxide layer of about 10 microns locally.

[0050] S2. The strip to be pickled is pickled to obtain a product strip. The pickling includes the steps of: immersing the strip to be pickled in a pickling solution, where the pickling solution includes hydrochloric acid and sodium phosphate. The concentration of the hydrochloric acid is 150 - 200 g / l, and the concentration of the sodium phosphate is 3% - 5%.

[0051] In some embodiments, the strip to be pickled is pickled to obtain a product strip and further includes the step of: subjecting the pickled strip to a skin pass treatment to obtain the product strip; wherein, the elongation of the skin pass treatment is not more than 2%.

[0052] In some embodiments, the skin pass treatment includes a four-high small rolling treatment. In the four-high small rolling treatment, the diameter of the backup roll is 500 - 600 mm, and the diameter of the work roll is 250 - 300 mm.

[0053] During the pickling process, the moving speed of the strip is 70 m / min - 90 m / min.

[0054] Compared with the prior art, the present invention has at least the following advantages:

[0055] The present invention provides a steel surface treatment technology, which is a method for removing the surface oxide layer of stainless steel with low cost, high surface quality, and high production line compatibility. Aiming at the composition structure of the scale on the strip surface, a combination of brush roll treatment, slurry grinding treatment, surface pickling technology, and surface skin pass technology is adopted in sequence. It mainly includes the following steps: brush roll treatment - slurry grinding treatment - pickling treatment. First, the Fe2O3 layer and Fe3O4 layer on the outer layer of the FeO scale are removed through the surface brush roll treatment, and at the same time, the FeO and the poor Cr layer are descaled. Then, the FeO and the poor Cr layer are removed through the mortar grinding treatment technology. Finally, through hydrochloric acid pickling and sodium phosphate rinsing and cleaning after the above treatment steps, the complete removal of the oxide layer on the strip to be treated is achieved.

[0056] The pickling solution used in the pickling treatment of the present invention includes hydrochloric acid with a concentration of 180 g / l and sodium phosphate with a concentration of 3% - 5%. Among them, hydrochloric acid can dissolve iron oxide and other metal element oxides, and sodium phosphate is a weak base salt of a strong base, which hydrolyzes in water to be alkaline. When sodium phosphate is used in combination with hydrochloric acid, a synergistic effect is produced, enhancing the pickling effect. At the same concentration, the acidity of the pickling solution used in the present invention is lower than that of the pickling solution used to treat stainless steel in the common technology. Combining with the aforementioned brush roll treatment and mortar grinding treatment, the compatible treatment of plain steel and stainless steel is realized, and while completely removing the steel oxide layer, the integrity of the steel surface and the tissue stability are ensured to the greatest extent.

[0057] In contrast, the patent with publication number CN116479429 A discloses a stainless steel pickling solution and its preparation method and usage method. Compared with the traditional hydrochloric acid pickling method, the formula of the pickling solution is extremely complex and the cost is relatively high. However, the pickling solution, its preparation method and usage method of the traditional hydrochloric acid pickling method are relatively simple. There are significant differences in the equipment investment for the two pickling methods, and neither can be compatible with the production of stainless steel and plain steel simultaneously. Moreover, according to actual production practices, when stainless steel is pickled to remove the surface oxide layer on the traditional hydrochloric acid pickling production line, the production efficiency is very low and the production cost is relatively high. That is, it is very uneconomical to solely use the traditional hydrochloric acid pickling method to remove the surface oxide layer of stainless steel.

[0058] The patent with publication number CN 218252181 U discloses a high-efficiency EPS treatment equipment for the oxide scale on the surface of steel strips. According to the production practices and related research of domestic EPS production lines, through energy spectrum scanning analysis of the surface of the finished products produced by the brush roll technology, oxides in most areas of the surface have fallen off and been removed, but there are still very few obvious Mn x O y 、Cr x O y 、Fe x O y and other oxide residues, and the oxide residues in the metallographic cross-section are about 10 - 20 μm thick. Through energy spectrum scanning and electron probe surface scanning analysis of the surface of the finished products produced by the EPS technology, oxides in most areas of the surface have fallen off and been removed, and no obvious oxide residues are seen, but about 5 μm thick oxide residues can be seen in the metallographic cross-section. That is to say, both the brush roll technology and the EPS technology cannot completely remove the oxide scale on the surface of hot-rolled steel plates.

[0059] In addition, from the macroscopic surface view, there are obvious differences in the surface colors of the finished products of the EPS production line and the pickling line. Compared with the finished products of the pickling line, the finished products of the EPS production line are black and bright

[0060] The present invention also provides an application of the steel surface treatment method as described in any one of the above in removing the oxide scale on the surfaces of stainless steel and plain steel.

[0061] For the convenience of those skilled in the art to further understand the present invention, examples are given below for illustration:

[0062] Example 1

[0063] S1. The strip to be processed is treated by a brush roll (sample No. 5 is taken after the brush roll, and its physical diagram is as Figure 1 shown) and then undergoes slurry grinding treatment to obtain the strip to be pickled (sample No. 1 is taken after slurry grinding, and its physical diagram is as Figure 1 shown); wherein, the strip to be processed includes stainless steel and plain steel;

[0064] The brush roll treatment includes rough brushing and fine brushing; the brush filaments of the rough brushing roll are nylon filaments containing silicon carbide abrasive, and their length is set to 1.5 - 1.7 mm; the brush filaments of the fine brushing roll are nylon filaments containing micro powder silicon carbide abrasive, and their length is set to 0.2 - 0.4 mm.

[0065] The material of the abrasive for slurry grinding treatment is steel shot, and its Vickers hardness is 800 kg / mm 2 ; the particle size of the slurry abrasive is 150; the shape of the slurry abrasive is small angular; the throwing speed of the slurry abrasive is 150 m / s - 250 m / s; the incident angle of the slurry abrasive projected onto the steel strip is 60° - 70°; the vertical height from the nozzle to the strip steel is 90 mm - 110 mm; the fan angle of the nozzle is 55° - 65°; the scattering angle of the nozzle is 25° - 35°; the nozzle diameter is 1.3 mm - 1.6 mm; the nozzle outlet pressure is 60 MPa - 70 MPa; the abrasive jet density is 3000 kg / m 3 -3100 kg / m 3 .

[0066] S2. The strip steel to be pickled is pickled (sample No. 3 is taken after pickling, and its physical drawing is as Figure 1 shown) and skin-passed to obtain the product strip steel. The pickling includes the steps of: immersing the strip steel to be pickled in the pickling solution, where the pickling solution includes hydrochloric acid and sodium phosphate, the concentration of the hydrochloric acid is 180 g / l, and the concentration of the sodium phosphate is 3% - 5%.

[0067] During the pickling treatment, the running speed of the steel strip is 70 m / min.

[0068] Among them, the thickness of the strip steel to be treated is 15 - 50 microns. After the heavy brushing treatment, the thickness of sample No. 5 is largely reduced, and the local part still maintains the original thickness. The metallographic diagram of the oxide layer of sample No. 5 at 200 times magnification is as Figure 2 , Figure 3 shown, and the schematic diagram of the oxygen element distribution intensity of sample No. 5 is as Figure 4 , Figure 5 shown. The surface energy spectrum analysis diagram of sample No. 5 is as Figure 16 shown, and the energy spectrum element analysis table is shown in Table 1.

[0069] Table 1 Energy spectrum element analysis table of sample No. 5

[0070]

[0071] After the slurry grinding treatment, the oxide layer of sample No. 1 is basically removed, and there is about 10 um of residue locally. The metallographic structure diagram of the oxide layer of sample No. 1 at 200 times magnification is as Figure 6 shown, and the schematic diagram of the oxygen element distribution intensity of sample No. 1 is as Figure 7 , Figure 8 shown. The surface energy spectrum analysis diagram of sample No. 1 is asFigure 17 As shown, the energy spectrum element analysis table is shown in Table 2.

[0072] Table 2 Energy Spectrum Element Analysis Table of Sample No. 1

[0073]

[0074] No residual oxide layer was found in Sample No. 3 obtained after pickling treatment. The schematic diagram of the oxygen element distribution intensity is as Figure 9 、 Figure 10 shown.

[0075] Smoothing parameters: The diameter of the four-roll small rolling backup roll is 500 - 600 mm, the diameter of the work roll is 250 - 300 mm, and the maximum elongation is 2%.

[0076] Comparative Example 1

[0077] In Comparative Example 1, other steps remained unchanged, only the step of brush roll treatment was deleted. After mortar grinding treatment, Sample No. 2 was sampled (the physical diagram of Sample No. 2 is as Figure 1 shown), and after pickling treatment, Sample No. 4 was sampled (the physical diagram of Sample No. 4 is as Figure 1 shown).

[0078] Among them, the metallographic diagram of Sample No. 2 at 200 times is as Figure 11 shown, and the schematic diagram of the oxygen element distribution intensity of Sample No. 2 is as Figure 12 、 Figure 13 shown.

[0079] The schematic diagram of the oxygen element distribution intensity of Sample No. 4 is as Figure 14 、 Figure 15 shown. The surface energy spectrum analysis diagram of Sample No. 4 is as Figure 18 shown, and the energy spectrum element analysis table is shown in Table 3.

[0080] Table 3 Energy Spectrum Element Analysis Table of Sample No. 4

[0081]

[0082] Analysis Example 1

[0083] Comparison of Surface Roughness of Finished Products with Different Process Technologies

[0084]

[0085] Compared with the stainless steel pickling technology, the industrial application acid solution of the present invention is simpler, more environmentally friendly, the product outline of the production line has better compatibility and a wider range; compared with the traditional pickling line for producing stainless steel, the production efficiency is higher and the production cost is lower; compared with the high-efficiency pickling-free EPS technology and the surface brush roll technology, the quality of removing the oxide layer on the stainless steel surface is better, and at the same time, the surface roughness is greatly improved.

[0086] In the above technical solution of the present invention, the above is only the preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A steel surface treatment technology, characterized in that, Including the steps: The strip to be processed is treated by a brush roll and slurry grinding to obtain the strip to be pickled; wherein, the strip to be processed includes stainless steel and common steel; The strip to be pickled is pickled to obtain the product strip. The pickling includes the steps of: immersing the strip to be pickled in pickling solution, the pickling solution includes hydrochloric acid and sodium phosphate, the concentration of the hydrochloric acid is 150 - 200 g / l, and the concentration of the sodium phosphate is 3 - 5%.

2. The steel surface treatment technology according to claim 1, wherein The brush roll treatment includes rough brushing and fine brushing. The brush filaments in the rough brushing include nylon filaments containing silicon carbide abrasive, the size of the brush filaments in the rough brushing is 1.5 - 1.7 mm, the brush filaments in the fine brushing include nylon filaments containing micro powder silicon carbide abrasive, and the size of the brush filaments in the fine brushing is 0.2 - 0.4 mm.

3. The steel surface treatment technology according to claim 1, characterized in that, The slurry grinding treatment includes the step of: a nozzle sprays slurry abrasive onto the strip to be processed after the brush roll treatment to achieve physical grinding, wherein, the throwing speed of the slurry abrasive is 150 m / s - 250 m / s.

4. The steel surface treatment technology according to claim 1, characterized in that, The density of the mortar abrasive jet is 3000 kg / m 3 ~3100 kg / m 3 , and the vertical height from the nozzle to the strip to be treated after being processed by the brush roll is 90 mm to 110 mm.

5. The steel surface treatment technology according to claim 4, characterized in that, The material of the mortar abrasive includes steel sand, and the Vickers hardness of the mortar abrasive is 600-1000 kg / mm 2 , the particle size of the mortar abrasive is 100-200 mesh; the shape of the mortar abrasive is small angular type.

6. The steel surface treatment technology according to claim 4, characterized in that, During the pickling process, the moving speed of the strip to be pickled is 70 m / min - 90 m / min.

7. The steel surface treatment technology according to claim 5, characterized in that, The fan angle of the nozzle is 55° - 65°, the scattering angle of the nozzle is 25° - 35°, the diameter of the nozzle is 1.3 mm - 1.6 mm, the outlet pressure of the nozzle is 60 MPa - 70 MPa, and the incident angle of the slurry abrasive projected onto the steel strip is 60° - 70°.

8. The steel surface treatment technology according to claim 1, characterized in that, The strip to be pickled is pickled to obtain the product strip and further includes the step of: the pickled strip is subjected to skin pass treatment to obtain the product strip; wherein, the elongation of the skin pass treatment is not more than 2%.

9. The steel surface treatment technology according to claim 8, wherein, The skin pass treatment includes four-high small rolling treatment. In the four-high small rolling treatment, the diameter of the backup roll is 500 - 600 mm, and the diameter of the work roll is 250 - 300 mm.

10. Application of the steel surface treatment method according to any one of claims 1 - 9 in removing the oxide layer on the surfaces of stainless steel and common steel.

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