Efficient pickling method suitable for high-carbon high-alloy hot-rolled steel plate

Abstract

The invention discloses a high-efficiency pickling method suitable for a high-carbon high-alloy hot-rolled steel plate, and mainly solves the problems of low pickling efficiency and poor pickling quality when the high-carbon high-alloy hot-rolled steel plate is pickled by an existing pickling unit provided with a pickling bath with the length of 30-60m. According to the technical scheme, the efficient acid pickling method suitable for the high-carbon and high-alloy hot-rolled steel plate comprises the steps that (1) the high-carbon and high-alloy hot-rolled steel plate is subjected to acid pickling, specifically, the hot-rolled steel plate is subjected to acid pickling through an acid pickling solution in an acid pickling tank, the acid pickling solution comprises hydrochloric acid, an acid pickling accelerant and iron ions, the mass concentration of the hydrochloric acid is 10%-18%, and the acidity of the acid solution is 120-160 g / L; the temperature of the acid liquor is 75-90 DEG C; 2) squeezing the steel plate after acid pickling; (3) the steel plate is rinsed; (4) the rinsed steel plate is squeezed to be dry; and 5) drying the steel plate. The method provided by the invention is suitable for a pickling line with a pickling bath with the length of 30-60m and a pickling line without a scale breaking device.

Description

Technical Field

[0001] The invention relates to a pickling method for hot-rolled steel plates, in particular to a high-efficiency pickling method suitable for high-carbon and high-alloy hot-rolled steel plates, belonging to the technical field of hot-rolled steel plate pickling. Background Art

[0002] Steel with a carbon content of 0.4%-2.0% and a total alloying element content greater than 1% is called high carbon high alloy steel. Pickling of high carbon high alloy steel plates is a pickling surface treatment technology that removes the surface oxide scale of high carbon high alloy hot rolled steel plates in batches and obtains a metallic luster effect on the surface of the finished product.

[0003] After hot rolling, high-carbon high-alloy steel will form a certain thickness of oxide scale on the surface of the high-carbon high-alloy hot-rolled steel plate from the outside to the inside. The oxide scale is mainly composed of FeO, Fe2O3, Fe3O4, and a small amount of eutectoid Fe, Si and Cr oxides. The oxide scale has the characteristics of dense structure and difficult pickling.

[0004] The pickling production of high-carbon and high-alloy hot-rolled steel plates mainly uses chemical pickling processes to remove oxide scales. The oxide scale of ordinary carbon steel plates is loose and has microcracks. The acid can reach the bottom layer of the oxide scale through the microcracks to dissolve and produce hydrogen, which causes the oxide scale to peel off. However, the structure of the outer layer of the oxide scale of high-carbon and high-alloy steel plates is quite dense, and it is difficult for the acid to penetrate the oxide layer to reach the substrate surface. The reaction between the acid and the substrate is difficult to proceed, and the peeling effect is difficult to occur. For some short pickling tank units without descaling devices, production is particularly difficult.

[0005] In the conventional pickling process, the main method is to increase the acid concentration and reduce the pickling speed of the steel strip. The oxide scale on the steel strip surface is still difficult to remove, which directly affects the quality of the steel strip product. The composition, thickness and density of the oxide scale of high-carbon high-alloy steel plates are different from those of ordinary carbon steel. The pickling process of ordinary carbon steel is not suitable for the pickling process of high-carbon high-alloy steel plates.

[0006] The Chinese patent application with application publication number CN109023388A discloses a method for efficient pickling surface treatment of high-strength automotive steel series strip, which is aimed at the 500-800MPa grade automotive steel series, improves the blackening of the strip surface and under-pickling, over-pickling, and improves the quality of the strip. The acid tank has five acid tanks with a total length of 100-150m; the acid tank is long, and the equipment investment and pickling cost are high.

[0007] The Chinese patent application with application publication number CN104985018A discloses a production method for improving the pickling performance of oxide scale of high carbon steel wire rod, which produces oxide scale that is easy to pickle by controlling the hot rolling process, but does not involve a pickling process.

[0008] The Chinese patent application with application publication number CN101949021A discloses a high-efficiency pickling tank, optimizes the structure of the pickling tank, and does not involve the pickling process.

[0009] The prior art lacks an effective method for pickling high-carbon and high-alloy hot-rolled steel plates, and the high-carbon and high-alloy hot-rolled steel plates have poor pickling quality and high pickling cost. Summary of the invention

[0010] The purpose of the present invention is to provide an efficient pickling method suitable for high-carbon high-alloy hot-rolled steel plates, which mainly solves the problem of low pickling efficiency and poor pickling quality of pickling high-carbon high-alloy hot-rolled steel plates in the existing pickling unit with a pickling tank length of 30-60m. The method realizes low-cost and efficient pickling of high-carbon high-alloy hot-rolled steel plates. The surface of the high-carbon high-alloy hot-rolled steel plates pickled by the method has no residual iron oxide scale and high surface quality.

[0011] The technical idea of ​​the present invention is to achieve the purpose of efficient pickling by optimizing the pickling process such as controlling the iron ion concentration in the acid solution, the acid solution additives, the acidity of the acid solution and the acid solution temperature.

[0012] The technical solution adopted by the present invention is an efficient pickling method suitable for high-carbon high-alloy hot-rolled steel plates, the method comprising:

[0013] 1) Pickling a high-carbon high-alloy hot-rolled steel plate, wherein the hot-rolled steel plate with a thickness of 2.0 to 12.7 mm is pickled by a pickling solution in a pickling tank, wherein the pickling solution comprises hydrochloric acid, a pickling accelerator and iron ions, wherein the mass concentration of the hydrochloric acid is 10% to 18%, and the acidity of the acid solution is 120 to 160 g / L; the temperature of the acid solution is 75 to 90° C.; the volume content of the pickling accelerator is 0.1% to 1.0% of the volume of the hydrochloric acid; the components of the pickling accelerator are: a mass fraction of carboxylate of 20% to 25%; a mass fraction of urea of ​​15% to 20%; a mass fraction of phosphates of 5% to 10%, and the remaining components are water; the mass concentration of iron ions is 10 to 100 mg / L; the mass content of carbon in the high-carbon high-alloy hot-rolled steel plate is 0.4% to 2.0%, and the sum of the mass contents of alloy elements is greater than 1%; and the length of the pickling tank is 30 to 60 m;

[0014] 2) After pickling, the steel plate is squeezed dry by using a pickling squeeze roller, and the pressure of the pickling squeeze roller is controlled to be 0.3-0.5MPa;

[0015] 3) rinsing the steel plate, rinsing the squeezed steel plate with rinsing water in a rinsing tank, wherein the rinsing water comprises industrial desalted water and a rinsing inhibitor, the conductivity of the rinsing water is ≤100 μs / cm, the pH value of the rinsing water is 6-9, and the temperature of the rinsing water is 30-70° C.; the rinsing inhibitor component comprises: a carboxylate mass fraction of 35%-40%, a fatty group carboxylic acid mass fraction of 1%-5%, an ammonium hydroxide mass fraction of <1%, and the remaining component is water;

[0016] 4) After rinsing, the steel plate is squeezed dry, and the rinsed steel plate is squeezed dry with a rinse and squeeze roller, and the pressure of the rinse and squeeze roller is controlled to be 0.3-0.5MPa;

[0017] 5) Drying of the steel plate: The steel plate after rinsing and squeezing is dried by hot air, the hot air temperature is 120-170°C, and the hot air pressure is 0.03-0.05MPa.

[0018] Furthermore, in step 1), when the length of the pickling tank is 30 to 40 m, adding a pickling accelerator into the last pickling tank has a good effect, which can reduce the risk of intergranular corrosion of high-carbon high-alloy steel plates while increasing the pickling speed.

[0019] When the length of the pickling tank is 50 to 60 m, adding a pickling accelerator at 1 / 2 to 3 / 4 of the total length of the pickling tank has a good effect, reducing the risk of intergranular corrosion of high-carbon high-alloy steel plates while increasing the pickling speed.

[0020] When the acid tank is a plurality of tanks connected in series, the volume concentration of the pickling accelerator in the pickling solution is distributed in a positive gradient from low concentration to high concentration, thereby increasing the pickling speed of the steel plate or steel strip and saving costs.

[0021] The method of the invention is applicable to a pickling unit equipped with a pickling tank with a length of 30 to 60 m and a pickling unit without a descaling device.

[0022] The method of the present invention is based on the following research findings:

[0023] The applicant has found through research that the process of removing oxide scale by hydrochloric acid pickling can be summarized into three aspects: the dissolution of iron oxide scale by acid reaction, the oxidation-reduction reaction, and the stripping effect of hydrogen. The principle is shown in the following chemical reaction:

[0024] Fe2O3+6HCl=2FeCl3+3H2O(1)

[0025] Fe3O4+8HCl=2FeCI3+FeCl2+4H2O (2)

[0026] FeO+2HCl=FeCl2+H20 (3)

[0027] Fe+2HCl=FeCl2+2[H] (4)

[0028] 2[H]=H2↑ (5)

[0029] FeCl3+[H]=FeCl2+HCl (6)

[0030] 2FeCl3+Fe=3FeCl2 (7)

[0031] Among them, reaction formula (4) and reaction formula (5) are that hydrochloric acid penetrates into the gap of iron oxide scale and reacts with elemental iron to generate hydrogen. The expansion force of hydrogen can be used to peel off part of the iron oxide scale from the surface of the steel plate. Reaction formula (1), reaction formula (2), and reaction formula (3) are chemical dissolution of iron oxide scale, which mainly reacts with hydrochloric acid to generate corresponding ions and dissolve into the acid solution. Reaction formula (6) and reaction formula (7) are mainly redox reactions, reducing trivalent iron to divalent iron. Among them, reaction (3) and reaction (4) react the fastest, and reaction (8) reacts the slowest. To speed up the reaction, it is necessary to speed up the reaction and increase the speed of each chemical reaction.

[0032] The increase of iron ions, especially the increase of trivalent iron ions, increases the self-corrosion current of the steel plate, indicating that the corrosion rate increases, thereby increasing the pickling speed.

[0033] The reasons for the production process adopted by the present invention are as follows:

[0034] 1. Setting of pickling acid composition and acid temperature

[0035] The process of removing scale by hydrochloric acid pickling can be summarized into three aspects: the dissolution of scale and acid reaction, the redox reaction and the stripping effect of hydrogen. Hydrochloric acid penetrates into the gaps of scale and reacts with elemental iron to generate hydrogen. The expansion force of hydrogen can be used to strip part of the scale from the surface of the steel plate. This process is affected by. On the other hand, the chemical reaction process of pickling is affected by the concentration and temperature of the acid solution. The higher the concentration of the acid solution and the higher the temperature of the acid solution, the faster the chemical reaction, and the scale on the surface of the steel plate or strip can be removed quickly. Taking into account the production cost and the actual bearing capacity of the equipment, this section sets the acid solution of the pickling tank to be hydrochloric acid with a mass fraction of 10% to 18%, and the acid temperature is 75℃ to 90℃.

[0036] 2. Setting of pickling accelerator in pickling acid solution

[0037] The functions of each component of the pickling accelerator are as follows: carboxylate is a negative ion, which acts as a surfactant and accelerates the penetration of acid into the iron oxide scale. Urea is a reducing agent, which activates the outer layer of the iron oxide scale and reacts the high-valent metal oxides on the outer layer of the iron oxide scale that are difficult to react with acid to form low-valent metal oxides that are easily soluble in acid, thereby accelerating the dissolution of the iron oxide scale; phosphate is an emulsifier and dispersant, which ensures that the carboxylate and urea are evenly distributed in the solution without deposition and aggregation.

[0038] The pickling accelerator in the acid solution can improve the activation of the iron oxide scale by the acid solution, reduce the high-valent iron in the iron oxide scale to low-valent iron, which is easier to react with the acid solution, increase the wettability of the acid solution, and make the acid solution quickly penetrate into the iron oxide scale to accelerate the reaction. The present invention is calculated based on the production speed of the unit. The volume fraction concentration of the pickling accelerator is 0.1% to 1.0% of the acid solution, which can meet the production needs of steel plates or steel strips at different speeds.

[0039] 3. Setting of iron ion content in pickling acid

[0040] The increase of iron ions in the acid solution, especially the increase of the content of trivalent iron ions, according to reaction formula (7), trivalent iron ions have strong oxidizing properties and can increase the chemical reaction of the solution. According to the inventor's electrochemical experiments, it is found that the self-corrosion current of the steel plate increases with the increase of iron ions, indicating that the corrosion rate increases, thereby increasing the pickling speed. However, according to the solution diffusion theory, too high iron ion content will reduce the chemical reaction speed of reaction formulas (1), (2), (3), and (4), so the iron ion content, iron ion concentration, and iron ion mass concentration are 10 to 100 mg / L.

[0041] Compared with the prior art, the present invention has the following positive effects: 1. The method of the present invention effectively combines the existing pickling process, and through the use of pickling accelerators, acid solution temperature, acidity of the acid solution and iron ion concentration, in combination with the unit process, the high-efficiency pickling of high-carbon and high-alloy hot-rolled steel plates is achieved while ensuring the surface quality of the product. 2. The present invention is suitable for pickling units equipped with pickling tanks with a length of 30 to 60m and pickling units without descaling devices, achieving high-efficiency pickling of high-carbon and high-alloy hot-rolled steel plates. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with Examples 1 to 5.

[0043] In Examples 1 to 5, the number of pickling tanks is 3, and the total length of the pickling tanks is 40 m.

[0044] Embodiment 1, an efficient pickling method for high carbon high alloy hot rolled steel plate, comprising the following steps:

[0045] 1) A high-carbon high-alloy hot-rolled steel plate was pickled. A 2.5 mm thick hot-rolled steel plate was pickled by a pickling solution in a pickling tank, wherein the pickling solution comprises hydrochloric acid, a pickling accelerator and iron ions, wherein the mass concentration of the hydrochloric acid is 18%, and the temperature of the acid solution is 80° C.; the volume content of the pickling accelerator in the pickling solution is 0.1%; the mass fraction of the pickling accelerator carboxylate is 20%; the mass fraction of urea is 20%; the mass fraction of phosphates is 10%; the remaining components are water; the iron ion concentration is 10 mg / L, and the acidity of the acid solution is 150 g / L;

[0046] 2) After pickling, the steel plate is squeezed dry by using a pickling squeeze roller to remove the acid on the surface of the steel plate by squeezing; the pressure of the pickling squeeze roller is controlled to be set to 0.3MPa;

[0047] 3) Rinse the steel plate by rinsing the steel plate after squeezing out with rinsing water in the rinsing tank, the conductivity of the rinsing water is ≤100μs / cm, the pH value is 6-9, the rinsing inhibitor model is BH2, the content is 0.1%, and the rinsing water temperature is 70°C;

[0048] 4) After rinsing, the steel plate is squeezed dry, and the rinsed steel plate is squeezed dry with a rinse squeeze roller to remove the rinsing water on the surface of the steel plate by squeezing; the pressure of the rinse squeeze roller is controlled to be 0.35MPa;

[0049] 5) Drying: The rinsed and squeezed steel plate is dried with hot air to remove residual moisture on the surface of the steel plate. The hot air temperature is 150° C. and the hot air pressure is 0.05 MPa.

[0050] The pickling speed of the steel type 60Si2Mn pickled in Example 1 is increased from 8 m / min in the existing conventional process to 15 m / min.

[0051] Embodiment 2, a high-efficiency pickling surface treatment technology for high-carbon high-alloy steel plates, comprising the following steps:

[0052] 1) A high-carbon high-alloy hot-rolled steel plate was pickled. A 5.99 mm thick hot-rolled steel plate was pickled by a pickling solution in a pickling tank, wherein the pickling solution included hydrochloric acid, a pickling accelerator and iron ions, the mass concentration of the hydrochloric acid was 16%, and the acid solution temperature was 85°C; the volume content of the pickling accelerator in the pickling solution was 0.3%; the mass fraction of the pickling accelerator carboxylate was 25%; the mass fraction of urea was 15%; the mass fraction of phosphates was 10%; the remaining components were water; the iron ion concentration was 30 mg / L, and the acidity of the acid solution was 180 g / L.

[0053] 2) After pickling, the steel plate is squeezed dry by using a pickling squeeze roller to remove the acid on the surface of the steel plate by squeezing; the pressure of the pickling squeeze roller is controlled to be set to 0.5MPa;

[0054] 3) Rinse the steel plate by rinsing the steel plate after squeezing out with rinsing water in the rinsing tank, the conductivity of the rinsing water is ≤100μs / cm, the pH value is 6-9, the rinsing inhibitor model is BH2, the content is 0.15%, and the rinsing water temperature is 70°C;

[0055] 4) After rinsing, the steel plate is squeezed dry, and the rinsed steel plate is squeezed dry with a rinse squeeze roller to remove the rinsing water on the surface of the steel plate by squeezing; the pressure of the rinse squeeze roller is controlled to be 0.4MPa;

[0056] 5) Drying: The rinsed and squeezed steel plate is dried with hot air to remove residual moisture on the surface of the steel plate. The hot air temperature is 150° C. and the hot air pressure is 0.05 MPa.

[0057] The pickling speed of the steel type 60Si2Mn pickled in Example 2 was increased from 8 m / min in the existing conventional process to 20 m / min.

[0058] Embodiment 3, a high-efficiency pickling surface treatment technology for high-carbon high-alloy steel plates, comprising the following steps:

[0059] 1) A high-carbon high-alloy hot-rolled steel plate was pickled. A 3.5 mm thick hot-rolled steel plate was pickled by a pickling solution in a pickling tank, wherein the pickling solution included hydrochloric acid, a pickling accelerator and iron ions, the mass concentration of the hydrochloric acid was 18%, and the acid solution temperature was 85°C; the volume content of the pickling accelerator in the pickling solution was 0.7%; the mass fraction of carboxylate in the pickling accelerator was 20%; the mass fraction of urea was 18%; the mass fraction of phosphates was 10%; the remaining components were water; the iron ion concentration was 20 mg / L, and the acid solution acidity was 195 g / L.

[0060] 2) After pickling, the steel plate is squeezed dry by using a pickling squeeze roller to remove the acid on the surface of the steel plate by squeezing; the pressure of the pickling squeeze roller is controlled to be set to 0.5MPa;

[0061] 3) Rinse the steel plate by rinsing the steel plate after squeezing out with rinsing water in the rinsing tank, the conductivity of the rinsing water is ≤100μs / cm, the pH value is 6-9, the rinsing inhibitor model is BH4, the content is 0.3%, and the rinsing water temperature is 60°C;

[0062] 4) After rinsing, the steel plate is squeezed dry, and the rinsed steel plate is squeezed dry with a rinse squeeze roller to remove the rinsing water on the surface of the steel plate by squeezing; the pressure of the rinse squeeze roller is controlled to be 0.5MPa;

[0063] 5) Drying: The rinsed and squeezed steel plate is dried with hot air to remove residual moisture on the surface of the steel plate. The hot air temperature is 150° C. and the hot air pressure is 0.05 MPa.

[0064] The pickling speed of the steel type 60Si2Mn pickled in Example 3 is increased from 8 m / min in the existing conventional process to 30 m / min.

[0065] Embodiment 4, a high-efficiency pickling surface treatment technology for high-carbon high-alloy steel plates, comprising the following steps:

[0066] 1) A high-carbon high-alloy hot-rolled steel plate was pickled. A 3.0 mm thick hot-rolled steel plate was pickled by a pickling solution in a pickling tank, wherein the pickling solution included hydrochloric acid, a pickling accelerator and iron ions, the mass concentration of the hydrochloric acid was 18%, and the acid solution temperature was 83°C; the volume content of the pickling accelerator in the pickling solution was 0.5%; the mass fraction of the pickling accelerator carboxylate was 22%; the mass fraction of urea was 15%; the mass fraction of phosphates was 8%; the remaining components were water; the iron ion concentration was 100 mg / L, and the acidity of the acid solution was 150 g / L.

[0067] 2) After pickling, the steel plate is squeezed dry by using a pickling squeeze roller to remove the acid on the surface of the steel plate by squeezing; the pressure of the pickling squeeze roller is controlled to be set to 0.5MPa;

[0068] 3) Rinse the steel plate by rinsing the steel plate after squeezing out with rinsing water in the rinsing tank, the conductivity of the rinsing water is ≤100μs / cm, the pH value is 6-9, the rinsing inhibitor model is BH2, the content is 0.2%, and the rinsing water temperature is 70°C;

[0069] 4) After rinsing, the steel plate is squeezed dry, and the rinsed steel plate is squeezed dry with a rinse squeeze roller to remove the rinsing water on the surface of the steel plate by squeezing; the pressure of the rinse squeeze roller is controlled to be 0.5MPa;

[0070] 5) Drying: The rinsed and squeezed steel plate is dried with hot air to remove residual moisture on the surface of the steel plate. The hot air temperature is 150° C. and the hot air pressure is 0.05 MPa.

[0071] The pickling speed of the steel grade SK85 pickled in Example 4 was increased from 40 m / min in the existing conventional process to 60 m / min.

[0072] Embodiment 5, a high-efficiency pickling surface treatment technology for high-carbon high-alloy steel plates, comprising the following steps:

[0073] 1) A high-carbon high-alloy hot-rolled steel plate was pickled. A 2.75 mm thick hot-rolled steel plate was pickled by a pickling solution in a pickling tank, wherein the pickling solution included hydrochloric acid, a pickling accelerator and iron ions, the mass concentration of the hydrochloric acid was 13%, and the acid solution temperature was 85°C; the volume content of the pickling accelerator in the pickling solution was 0.7%; the mass fraction of the pickling accelerator carboxylate was 25%; the mass fraction of urea was 20%; the mass fraction of phosphates was 5%; the remaining components were water; the iron ion concentration was 80 mg / L, and the acidity of the acid solution was 160 g / L.

[0074] 2) After pickling, the steel plate is squeezed dry by using a pickling squeeze roller to remove the acid on the surface of the steel plate by squeezing; the pressure of the pickling squeeze roller is controlled to be set to 0.5MPa;

[0075] 3) Rinse the steel plate by rinsing the steel plate after squeezing out with rinsing water in the rinsing tank, the conductivity of the rinsing water is ≤100μs / cm, the pH value is 6-9, the rinsing inhibitor model is BH4, the content is 0.2%, and the rinsing water temperature is 70°C;

[0076] 4) After rinsing, the steel plate is squeezed dry, and the rinsed steel plate is squeezed dry with a rinse squeeze roller to remove the rinsing water on the surface of the steel plate by squeezing; the pressure of the rinse squeeze roller is controlled to be 0.5MPa;

[0077] 5) Drying: The rinsed and squeezed steel plate is dried with hot air to remove residual moisture on the surface of the steel plate. The hot air temperature is 150° C. and the hot air pressure is 0.05 MPa.

[0078] The pickling speed of the steel grade SK85 pickled in Example 5 was increased from 40 m / min in the existing conventional process to 55 m / min.

[0079] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. An efficient pickling method suitable for high-carbon high-alloy hot-rolled steel plates, characterized in that: The method comprises the following steps: 1) Pickling a high-carbon high-alloy hot-rolled steel plate, wherein the hot-rolled steel plate with a thickness of 2.0 to 12.7 mm is pickled by a pickling solution in a pickling tank, wherein the pickling solution comprises hydrochloric acid, a pickling accelerator and iron ions, wherein the mass concentration of the hydrochloric acid is 10% to 18%, and the acidity of the acid solution is 120 to 160 g / L; the temperature of the acid solution is 75 to 90° C.; the volume content of the pickling accelerator is 0.1% to 1.0% of the volume of the hydrochloric acid; the components of the pickling accelerator are: a mass fraction of carboxylate of 20% to 25%; a mass fraction of urea of ​​15% to 20%; a mass fraction of phosphates of 5% to 10%, and the remainder is water; a mass concentration of iron ions of 10 to 100 mg / L; the mass content of carbon in the high-carbon high-alloy hot-rolled steel plate is 0.4% to 2.0%, and the sum of the mass contents of alloy elements is greater than 1%; and the length of the pickling tank is 30 to 60 m; 2) After pickling, the steel plate is squeezed dry by using a pickling squeeze roller, and the pressure of the pickling squeeze roller is controlled to be 0.3-0.5MPa; 3) rinsing the steel plate, rinsing the squeezed steel plate with rinsing water in a rinsing tank, wherein the rinsing water comprises industrial desalted water and a rinsing inhibitor, the conductivity of the rinsing water is ≤100 μs / cm, the pH value of the rinsing water is 6-9, and the temperature of the rinsing water is 30-70° C.; the rinsing inhibitor component comprises: a carboxylate mass fraction of 35%-40%, a fatty group carboxylic acid mass fraction of 1%-5%, an ammonium hydroxide mass fraction of <1%, and the remaining component is water; 4) After rinsing, the steel plate is squeezed dry, and the rinsed steel plate is squeezed dry with a rinse and squeeze roller, and the pressure of the rinse and squeeze roller is controlled to be 0.3-0.5MPa; 5) Drying of the steel plate: The steel plate after rinsing and squeezing is dried by hot air, the hot air temperature is 120-170°C, and the hot air pressure is 0.03-0.05MPa.

2. The efficient pickling method for high-carbon high-alloy hot-rolled steel sheets as claimed in claim 1, characterized in that: When the length of the pickling tank is 30 to 40 m, a pickling accelerator is added to the last pickling tank.

3. The efficient pickling method for high-carbon high-alloy hot-rolled steel sheets according to claim 1, characterized in that: When the length of the pickling tank is 50 to 60 m, the pickling accelerator is added at a position of 1 / 2 to 3 / 4 of the total length of the pickling tank.

4. The efficient pickling method for high-carbon high-alloy hot-rolled steel sheets as claimed in claim 1, characterized in that: When the pickling tank is a plurality of tanks connected in series, the volume concentration of the pickling accelerator in the pickling solution is distributed in a positive gradient from a low concentration to a high concentration.