Method for reducing low-temperature corrosion and pickling deficiency defects of nickel-saving austenitic stainless steel

Abstract

The present invention relates to the technical field of strip steel production in a continuous annealing production line, and specifically to a method for reducing the low-temperature corrosion and insufficient pickling defects of nickel-saving austenitic stainless steel. The thickness of the nickel-saving austenitic stainless steel plate is more than 2 mm, and specifically as follows: controlling the gas flow rate and air flow rate in the first to third furnace zones of the continuous rolling, annealing and pickling line; controlling the combustion air pressure of the continuous rolling, annealing and pickling line; controlling the furnace head negative pressure of the continuous rolling, annealing and pickling line; controlling that the continuous annealing and pickling line uses at least one set of final cleaning section brush rolls; controlling the gas flow rate and air flow rate in the first and second furnace zones of the continuous annealing and pickling line; controlling the furnace head negative pressure of the continuous annealing and pickling line; controlling the furnace head negative pressure of the continuous annealing and pickling line to be 20 ± 5 PA. Reducing the low-temperature corrosion and insufficient pickling defects of the 2B thick plate (thickness greater than 2.0 mm) coils of nickel-saving austenitic stainless steel.

Description

Technical Field

[0001] The present invention relates to the technical field of strip steel production in a continuous annealing and pickling line, and specifically to a method for reducing low-temperature corrosion and pickling deficiency defects of nickel-saving austenitic stainless steel. Background Art

[0002] Nickel-saving austenitic stainless steel is a metastable austenitic stainless steel obtained by partially replacing nickel in chromium-nickel stainless steel with manganese and nitrogen. This series of steels has good strength, plasticity and considerable corrosion resistance, and its corrosion resistance can be comparable to that of 304 stainless steel under general service environments; therefore, it is extremely widely used, mainly in civil fields such as kitchen and bathroom equipment and utensils, and building decoration industries.

[0003] However, 2B thick plates (thickness greater than 2.0 mm) of nickel-saving austenitic stainless steel coils are extremely prone to low-temperature corrosion and pickling deficiency defects. Those skilled in the art have adjusted the furnace zone heating curve, acid zone concentration, production parameters of the previous process, and even adjusted the composition of the steel grade, but the defects still cannot be improved, which is a technical problem urgently to be solved in this field. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a method for reducing low-temperature corrosion and pickling deficiency defects of nickel-saving austenitic stainless steel. It reduces low-temperature corrosion and pickling deficiency defects of 2B thick plates (thickness greater than 2.0 mm) of nickel-saving austenitic stainless steel coils.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0006] A method for reducing low-temperature corrosion and pickling deficiency defects of nickel-saving austenitic stainless steel, where the thickness of the nickel-saving austenitic stainless steel plate is above 2 mm, specifically as follows:

[0007] 1) Control the gas flow rate and air flow rate in the first furnace zone of the continuous rolling, annealing and pickling line (WRAP);

[0008] Control the gas flow rate in the first furnace zone of the continuous rolling, annealing and pickling line to be 50 - 100 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous rolling, annealing and pickling line to be 3500 - 4000 NM 3 / H;

[0009] 2) Control the gas flow rate and air flow rate in the second furnace zone of the continuous rolling, annealing and pickling line;

[0010] Control the gas flow rate in the second furnace zone of the continuous rolling, annealing and pickling line to be 100 - 150 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous rolling, annealing and pickling line to be 4000 - 5000 NM 3 / H;

[0011] 3) Control the gas flow rate and air flow rate in the third furnace zone of the continuous rolling annealing pickling line;

[0012] Control the gas flow rate in the third furnace zone of the continuous rolling annealing pickling line to be 100 - 150 NM 3 / H, and control the air flow rate in the third furnace zone of the continuous rolling annealing pickling line to be 4000 - 5000 NM 3 / H;

[0013] 4) Control the combustion air pressure of the continuous rolling annealing pickling line;

[0014] Control the combustion air pressure of the continuous rolling annealing pickling line to be ≥6.6 KPA;

[0015] 5) Control the negative pressure at the furnace head of the continuous rolling annealing pickling line;

[0016] Control the negative pressure at the furnace head of the continuous rolling annealing pickling line to be 30 ± 5 PA;.

[0017] 6) Control the continuous rolling annealing pickling line to use at least one set of final cleaning section brush rolls;

[0018] 7) Control the gas flow rate and air flow rate in the first furnace zone of the continuous annealing pickling line (CAPL);

[0019] Control the gas flow rate in the first furnace zone of the continuous annealing pickling line to be 50 - 100 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous annealing pickling line to be 2000 - 3000 NM 3 / H;

[0020] 8) Control the gas flow rate and air flow rate in the second furnace zone of the continuous annealing pickling line;

[0021] Control the gas flow rate in the second furnace zone of the continuous annealing pickling line to be 100 - 200 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous annealing pickling line to be 3000 - 4000 NM 3 / H;

[0022] 9) Control the negative pressure at the furnace head of the continuous annealing pickling line;

[0023] Control the negative pressure at the furnace head of the continuous annealing pickling line to be 20 ± 5 PA;

[0024] 10) Control the continuous annealing pickling line to use at least one set of final cleaning section brush rolls (FR07).

[0025] Further, 1) control the gas flow rate in the first furnace zone of the continuous rolling annealing pickling line to be 70 - 100 NM3 / H, and control the air flow rate in the first furnace zone of the continuous rolling annealing pickling line to be 3800 - 4000 NM3 / H.

[0026] Further, 2) control the gas flow rate in the second furnace zone of the continuous rolling annealing pickling line to be 110 - 135 NM3 / H, and control the air flow rate in the second furnace zone of the continuous rolling annealing pickling line to be 4150 - 5000 NM3 / H.

[0027] Further, 3) control the gas flow rate in the third furnace zone of the continuous rolling annealing pickling line to be 120 - 145 NM3 / H, and control the air flow rate in the third furnace zone of the continuous rolling annealing pickling line to be 4700 - 5000 NM3 / H.

[0028] Further, 7) control the gas flow rate in the first furnace zone of the continuous annealing pickling line to be 60 - 100 NM3 / H, and control the air flow rate in the first furnace zone of the continuous annealing pickling line to be 2250 - 3000 NM3 / H.

[0029] Further, 8) control the gas flow rate in the second furnace zone of the continuous annealing pickling line to be 100 - 140 NM3 / H, and control the air flow rate in the second furnace zone of the continuous annealing pickling line to be 3450 - 4000 NM3 / H.

[0030] Compared with the existing method, the beneficial effects of the present invention are as follows:

[0031] When the gas flow rate is large, the diameter of the flame increases, and the distance between the outer flame and the steel strip shortens, forming the outer flame to roast the surface of the steel strip. Small rust spots that are difficult to pickle are generated on the surface of the steel strip, resulting in the defect of insufficient pickling. At the same time, because the production line improves the defect of insufficient pickling of the steel strip and reduces the steel strip out of the furnace, the steel strip fails to reach the solution temperature, forming the defect of low-temperature corrosion. Finally, both the high-temperature pickling deficiency defect and the low-temperature low-temperature corrosion defect exist on the surface of the steel strip.

[0032] By restricting the gas flow rate in the furnace zone, the present invention reduces the flame diameter and controls the defect rate within a reasonable range. The degradation rate of low-temperature corrosion and insufficient pickling defects is reduced from an average of 30% before improvement to less than 5% after improvement. The quality is significantly improved, and the rework cost is greatly saved. Description of the Drawings

[0033] Figure 1 It is the laminar diffusion flame structure formed by concentric jets. Detailed Embodiments

[0034] The present invention discloses a method for reducing low-temperature corrosion and pickling deficiency defects of nickel-saving austenitic stainless steel. Those skilled in the art can draw on the content of this article and appropriately improve the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously make changes or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0035] According to Figure 1 The laminar diffusion flame structure formed by the concentric jets shown.

[0036] According to the flame diameter calculation formula:

[0037]

[0038] d - The diameter at the top of the flame, m;

[0039] W - The maximum emission of the flame, kg / h;

[0040] P - The gas pressure at the top of the flame, kPa;

[0041] Ma - Mach number, the ratio of the flame gas flow to the sound speed of the fluid;

[0042] M - The average molecular weight of the flame;

[0043] K - Adiabatic index:

[0044] T - The flame gas temperature under operating conditions, K.

[0045] Z - Gas compression factor.

[0046] The formula shows that when the fuel composition is certain, the length of the laminar diffusion flame mainly depends on the volume flow rate. When the flow rate is certain, the flame length is independent of the diameter; if the flow velocity is certain, the flame length increases with the increase of the diameter (increase of the flow rate); if the diameter is certain, the flame length increases with the increase of the flow velocity (increase of the flow rate).

[0047] Therefore, to avoid the flame burning the surface of the steel strip, it can be improved by two means: 1. By reducing the volume flow rate by reducing gas and air to reduce the flame diameter; 2. When the flow rate is certain, by increasing the flow velocity, the flame diameter can be reduced.

[0048] A method for reducing low-temperature corrosion and pickling deficiency defects of nickel-saving austenitic stainless steel, the thickness of the nickel-saving austenitic stainless steel plate is more than 2 mm, specifically as follows:

[0049] A method for reducing low-temperature corrosion and insufficient pickling defects of nickel-saving austenitic stainless steel, where the thickness of the nickel-saving austenitic stainless steel plate is more than 2 mm, specifically as follows:

[0050] 1) Control the gas flow rate and air flow rate in the first furnace zone of the continuous rolling, annealing and pickling line (WRAP);

[0051] Control the gas flow rate in the first furnace zone of the continuous rolling, annealing and pickling line to be 50 - 100 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous rolling, annealing and pickling line to be 3500 - 4000 NM 3 / H;

[0052] 2) Control the gas flow rate and air flow rate in the second furnace zone of the continuous rolling, annealing and pickling line;

[0053] Control the gas flow rate in the second furnace zone of the continuous rolling, annealing and pickling line to be 100 - 150 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous rolling, annealing and pickling line to be 4000 - 5000 NM 3 / H;

[0054] 3) Control the gas flow rate and air flow rate in the third furnace zone of the continuous rolling, annealing and pickling line;

[0055] Control the gas flow rate in the third furnace zone of the continuous rolling, annealing and pickling line to be 100 - 150 NM 3 / H, and control the air flow rate in the third furnace zone of the continuous rolling, annealing and pickling line to be 4000 - 5000 NM 3 / H;

[0056] 4) Control the combustion air pressure of the continuous rolling, annealing and pickling line;

[0057] Control the combustion air pressure of the continuous rolling, annealing and pickling line to be ≥6.6 KPA;

[0058] 5) Control the furnace head negative pressure of the continuous rolling, annealing and pickling line;

[0059] Control the furnace head negative pressure of the continuous rolling, annealing and pickling line to be 30 ± 5 PA;.

[0060] 6) Control the continuous rolling, annealing and pickling line to use at least one set of final cleaning section brush rolls;

[0061] 7) Control the gas flow rate and air flow rate in the first furnace zone of the continuous annealing and pickling line (CAPL);

[0062] Control the gas flow rate in the first furnace zone of the continuous annealing and pickling line to be 50 - 100 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous annealing and pickling line to be 2000 - 3000 NM 3 / H;

[0063] 8) Control the gas flow rate and air flow rate in the second furnace zone of the continuous annealing and pickling line;

[0064] Control the gas flow rate in the second furnace zone of the continuous annealing and pickling line to be 100 - 200 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous annealing and pickling line to be 3000 - 4000 NM 3 / H;

[0065] 9) Control the negative pressure at the furnace head of the continuous annealing and pickling line;

[0066] Control the negative pressure at the furnace head of the continuous annealing and pickling line to be 20 ± 5 PA;

[0067] 10) Control the continuous annealing and pickling line to use at least one set of final cleaning section brush rolls (FR07).

[0068]

Example

[0069] Example 1:

[0070] A method for reducing the low - temperature corrosion and pickling deficiency defects of nickel - saving austenitic stainless steel. In February 2023, the steel mill produced 365 tons of steel coils with a thickness of more than 2 mm of nickel - saving austenitic stainless steel plates, and the first - grade product rate was 100%. The specific conditions are as follows:

[0071] 1) Control the gas flow rate and air flow rate in the first furnace zone of the continuous rolling, annealing and pickling line;

[0072] Control the gas flow rate in the first furnace zone of the continuous rolling, annealing and pickling line to be 90 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous rolling, annealing and pickling line to be 3900 NM 3 / H;

[0073] 2) Control the gas flow rate and air flow rate in the second furnace zone of the continuous rolling, annealing and pickling line;

[0074] Control the gas flow rate in the second furnace zone of the continuous rolling, annealing and pickling line to be 130 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous rolling, annealing and pickling line to be 4500 NM 3 / H;

[0075] 3) Control the gas flow rate and air flow rate in the third furnace zone of the continuous rolling, annealing and pickling line;

[0076] Control the gas flow rate in the third furnace zone of the continuous rolling, annealing and pickling line to be 135 NM 3 / H, and control the air flow rate in the third furnace zone of the continuous rolling, annealing and pickling line to be 4800 NM 3 / H;

[0077] 4) Control the combustion air pressure of the continuous rolling annealing pickling line;

[0078] Control the combustion air pressure of the continuous rolling annealing pickling line to be ≥6.6 KPA;

[0079] 5) Control the negative pressure at the furnace head of the continuous rolling annealing pickling line;

[0080] Control the negative pressure at the furnace head of the continuous rolling annealing pickling line to be 30 ± 5 PA;

[0081] 6) Control the continuous rolling annealing pickling line to use two groups of FR07 brush rolls;

[0082] 7) Control the gas flow rate and air flow rate in the first furnace zone of the continuous annealing pickling line;

[0083] Control the gas flow rate in the first furnace zone of the continuous annealing pickling line to be 85 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous annealing pickling line to be 2450 NM 3 / H;

[0084] 8) Control the gas flow rate and air flow rate in the second furnace zone of the continuous annealing pickling line;

[0085] Control the gas flow rate in the second furnace zone of the continuous annealing pickling line to be 100 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous annealing pickling line to be 3450 NM 3 / H;

[0086] 9) Control the negative pressure at the furnace head of the continuous annealing pickling line;

[0087] Control the negative pressure at the furnace head of the continuous annealing pickling line to be 20 ± 5 A;

[0088] 10) Control the continuous annealing pickling line to use two groups of final cleaning section brush rolls.

[0089] Example 2:

[0090] A method for reducing low-temperature corrosion and pickling deficiency defects of nickel-saving austenitic stainless steel. In March 2023, 563 tons of steel coils with a thickness of more than 2 mm of nickel-saving austenitic stainless steel plates were produced, and the first-class product rate was 98.5%. The specific details are as follows:

[0091] 1) Control the gas flow rate and air flow rate in the first furnace zone of the continuous rolling annealing pickling line;

[0092] Control the gas flow rate in the first furnace zone of the continuous rolling annealing pickling line to be 70 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous rolling annealing pickling line to be 3800 NM 3 / H;

[0093] 2) Control the gas flow rate and air flow rate in the second furnace zone of the continuous rolling annealing pickling line;

[0094] Control the gas flow rate in the second furnace zone of the continuous rolling annealing pickling line to be 110 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous rolling annealing pickling line to be 4150 NM 3 / H;

[0095] 3) Control the gas flow rate and air flow rate in the third furnace zone of the continuous rolling annealing pickling line;

[0096] Control the gas flow rate in the third furnace zone of the continuous rolling annealing pickling line to be 120 NM 3 / H, and control the air flow rate in the third furnace zone of the continuous rolling annealing pickling line to be 4700 NM 3 / H;

[0097] 4) Control the combustion air pressure of the continuous rolling annealing pickling line;

[0098] Control the combustion air pressure of the continuous rolling annealing pickling line to be ≥6.60 KPA;

[0099] 5) Control the furnace head negative pressure of the continuous rolling annealing pickling line;

[0100] Control the furnace head negative pressure of the continuous rolling annealing pickling line to be 30 ± 5 PA;.

[0101] 6) Control the continuous rolling annealing pickling line to use at least one set of FR07 brush rolls;

[0102] 7) Control the gas flow rate and air flow rate in the first furnace zone of the continuous annealing pickling line;

[0103] Control the gas flow rate in the first furnace zone of the continuous annealing pickling line to be 60 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous annealing pickling line to be 2250 NM 3 / H;

[0104] 8) Control the gas flow rate and air flow rate in the second furnace zone of the continuous annealing pickling line;

[0105] Control the gas flow rate in the second furnace zone of the continuous annealing pickling line to be 120 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous annealing pickling line to be 3600 NM 3 / H;

[0106] 9) Control the furnace head negative pressure of the continuous annealing pickling line;

[0107] Control the furnace head negative pressure of the continuous annealing pickling line to be 20 ± 5 PA;.

[0108] 10) Control at least one set of final cleaning section brush rolls for the continuous annealing and pickling line.

[0109] Example 3:

[0110] A method for reducing the low-temperature corrosion and pickling deficiency defects of nickel-saving austenitic stainless steel. On April 6, 2023, 468 tons of steel coils with a thickness of more than 2 mm of nickel-saving austenitic stainless steel plates were produced, and the first-class product rate was 98.1%. Specifically as follows:

[0111] 1) Control the gas flow rate and air flow rate in the first furnace zone of the continuous rolling, annealing and pickling line;

[0112] Control the gas flow rate in the first furnace zone of the continuous rolling, annealing and pickling line to be 90 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous rolling, annealing and pickling line to be 4000 NM 3 / H;

[0113] 2) Control the gas flow rate and air flow rate in the second furnace zone of the continuous rolling, annealing and pickling line;

[0114] Control the gas flow rate in the second furnace zone of the continuous rolling, annealing and pickling line to be 135 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous rolling, annealing and pickling line to be 4900 NM 3 / H;

[0115] 3) Control the gas flow rate and air flow rate in the third furnace zone of the continuous rolling, annealing and pickling line;

[0116] Control the gas flow rate in the third furnace zone of the continuous rolling, annealing and pickling line to be 145 NM 3 / H, and control the air flow rate in the third furnace zone of the continuous rolling, annealing and pickling line to be 5000 NM 3 / H;

[0117] 4) Control the combustion air pressure of the continuous rolling, annealing and pickling line;

[0118] Control the combustion air pressure of the continuous rolling, annealing and pickling line to be ≥6.6 KPA;

[0119] 5) Control the furnace head negative pressure of the continuous rolling, annealing and pickling line;

[0120] Control the furnace head negative pressure of the continuous rolling, annealing and pickling line to be 30 ± 5 PA;

[0121] 6) Control at least one set of FR07 brush rolls for the continuous rolling, annealing and pickling line;

[0122] 7) Control the gas flow rate and air flow rate in the first furnace zone of the continuous annealing and pickling line;

[0123] Control the gas flow rate in the first furnace zone of the continuous annealing and pickling line to 80 NM 3 / H, and control the air flow rate in the first furnace zone of the continuous annealing and pickling line to 2400 NM 3 / H;

[0124] 8) Control the gas flow rate and air flow rate in the second furnace zone of the continuous annealing and pickling line;

[0125] Control the gas flow rate in the second furnace zone of the continuous annealing and pickling line to 135 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous annealing and pickling line to 3950 NM 3 / H;

[0126] 9) Control the negative pressure at the furnace head of the continuous annealing and pickling line;

[0127] Control the negative pressure at the furnace head of the continuous annealing and pickling line to 20 ± 5 PA;.

[0128] 10) Control the continuous annealing and pickling line to use at least one set of final cleaning section brush rolls.

[0129] Compare the prior art with the low-temperature corrosion degradation rate and pickling deficiency degradation rate of this method, as shown in Table 1.

[0130] Table 1 Comparison table of the prior art and this method

[0131]

[0132] The present invention controls the defect rate within a reasonable range by restricting the gas flow rate in the furnace zone and reducing the flame diameter. This technology has been applied to the cold rolling annealing and pickling line of Angang Lisheng (Guangzhou) Stainless Steel Co., Ltd. since January 2022. The degradation rates of low-temperature corrosion and pickling deficiency defects have been reduced from an average of 30% before improvement to less than 5% after improvement. The quality has been significantly improved and the rework cost has been greatly saved.

[0133] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A method for reducing low-temperature corrosion and pickling deficiency defects of nickel-saving austenitic stainless steel, characterized in that The thickness of the nickel-free austenitic stainless steel plate is more than 2 mm, specifically as follows: 1) Control the gas flow rate and air flow rate in the first furnace zone of the continuous rolling annealing pickling line; Control the gas flow rate in the first furnace area of the continuous rolling annealing pickling line to be 50 - 100 NM 3 / H, and control the air flow rate in the first furnace area of the continuous rolling annealing pickling line to be 3500 - 4000 NM 3 / H; 2) Control the gas flow rate and air flow rate in the second furnace zone of the continuous rolling annealing pickling line; Control the gas flow rate in the second furnace zone of the continuous rolling annealing and pickling line to be 100 - 150 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous rolling annealing and pickling line to be 4000 - 5000 NM 3 / H; 3) Control the gas flow rate and air flow rate in the third furnace zone of the continuous rolling annealing pickling line; Control the gas flow rate in the third furnace zone of the continuous rolling annealing and pickling line to be 100 - 150 NM 3 / H, and control the air flow rate in the third furnace zone of the continuous rolling annealing and pickling line to be 4000 - 5000 NM 3 / H; 4) Control the combustion air pressure of the continuous rolling annealing pickling line; Control the combustion air pressure of the continuous rolling annealing pickling line to be ≥6.6 KPA; 5) Control the furnace head negative pressure of the continuous rolling annealing pickling line; Control the furnace head negative pressure of the continuous rolling annealing pickling line to be 30 ± 5 PA; 6) Control the continuous rolling annealing pickling line to use at least one set of brush rolls in the final cleaning section; 7) Control the gas flow rate and air flow rate in the first furnace zone of the continuous annealing pickling line; Control the gas flow rate in the first furnace area of the continuous annealing and pickling line to be 50 - 100 NM 3 / H, and control the air flow rate in the first furnace area of the continuous annealing and pickling line to be 2000 - 3000 NM 3 / H; 8) Control the gas flow rate and air flow rate in the second furnace zone of the continuous annealing pickling line; Control the gas flow rate in the second furnace zone of the continuous annealing and pickling line to be 100 - 200 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous annealing and pickling line to be 3000 - 4000 NM 3 / H; 9) Control the furnace head negative pressure of the continuous annealing pickling line; Control the furnace head negative pressure of the continuous annealing pickling line to be 20 ± 5 PA; 10) Control the continuous annealing pickling line to use at least one set of brush rolls in the final cleaning section.

2. The method for reducing the low-temperature corrosion and pickling deficiency defects of the nickel-free austenitic stainless steel according to claim 1, characterized in that, 1) Control the gas flow rate in the first furnace area of the continuous rolling annealing and pickling line to be 70 - 100 NM 3 / H, and control the air flow rate in the first furnace area of the continuous rolling annealing and pickling line to be 3800 - 4000 NM 3 / H.

3. The method for reducing the low-temperature corrosion and pickling deficiency defects of the nickel-free austenitic stainless steel according to claim 1, characterized in that, 2) Control the gas flow rate in the second furnace zone of the continuous rolling annealing pickling line to be 110 - 135 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous rolling annealing pickling line to be 4150 - 5000 NM 3 / H.

4. The method for reducing the low-temperature corrosion and pickling deficiency defects of the nickel-free austenitic stainless steel according to claim 1, characterized in that, 3) Control the gas flow rate in the third furnace zone of the continuous rolling annealing pickling line to be 120 - 145 NM 3 / H, and control the air flow rate in the third furnace zone of the continuous rolling annealing pickling line to be 4700 - 5000 NM 3 / H.

5. The method for reducing the low-temperature corrosion and pickling deficiency defects of the nickel-free austenitic stainless steel according to claim 1, characterized in that, 7) Control the gas flow rate in the first furnace area of the continuous annealing and pickling line to be 60 - 100 NM 3 / H, and control the air flow rate in the first furnace area of the continuous annealing and pickling line to be 2250 - 3000 NM 3 / H.

6. The method for reducing the low-temperature corrosion and pickling deficiency defects of the nickel-free austenitic stainless steel according to claim 1, characterized in that, 8) Control the gas flow rate in the second furnace zone of the continuous annealing and pickling line to be 100 - 140 NM 3 / H, and control the air flow rate in the second furnace zone of the continuous annealing and pickling line to be 3450 - 4000 NM 3 / H.

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