Production method of thin-gauge sulfuric acid dew point corrosion resistant steel

Abstract

The invention discloses a production method of thin-gauge sulfuric acid dew point corrosion resistant steel. A hot rolling production technological process comprises the steps of slab heating, high-pressure water descaling, a fixed-width press, rolling of an E1R1 roughing mill, rolling of an E2R2 roughing mill, flying shearing, high-pressure water descaling, rolling of an F1F7 finishing mill, dense laminar cooling, coiling, warehousing, sampling, inspecting, weighing and packaging. The mass percentage content of the chemical components is as follows: 0.06-0.08% of C; 0.20% to 0.30% of Si; mn: 0.35 to 0.45%; p: less than or equal to 0.02%; s: less than or equal to 0.008%; 0.20% to 0.25% of Cu; cr: 0.35 to 0.45%; 0.05 to 0.10 percent of Sb, and the balance of Fe and impurities. A conventional C-Si-Mn component system design is adopted, and the sulfuric acid dew point corrosion resistance of the steel strip is improved by adding corrosion-resistant elements Cu, Cr and Sbi.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical plate production technology, and particularly relates to a production method of thin-gauge steel resistant to sulfuric acid dew point corrosion. Background Technology

[0002] In industries such as metallurgy, power generation, and petrochemicals, heavy oil or coal typically contains 2%–3% sulfur. After combustion, the flue gas contains approximately 0.2% sulfur dioxide (SO2). Of this, 1%–2% of SO2 is catalyzed by ash and metal oxides to produce sulfur trioxide (SO3). SO3 then combines with moisture in the combustion gas (approximately 5%–10%) or in the air to form sulfuric acid. When the temperature is below the acid dew-point temperature (ADT) (approximately 130–150°C when the SO3 content in the flue gas is 30 × 10⁻⁶), dew droplets condense on low-temperature parts of equipment such as oil-fired or coal-fired boilers, including air preheaters, economizers, flues, chimneys, and desulfurization devices, corroding the metal. This is known as sulfuric acid dew-point corrosion.

[0003] Steel plates resistant to sulfuric acid dew point corrosion are widely used and have achieved good results in the application of sulfuric acid dew point corrosion resistant materials in industries such as steel enterprises, gas pipelines, chemical industry, power industry, and tobacco industry, due to their low cost and excellent acid resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for producing thin-gauge sulfuric acid dew point corrosion resistant steel. The method adopts a conventional C-Si-Mn composition system and improves the sulfuric acid dew point corrosion resistance of the steel strip by adding corrosion-resistant elements Cu, Cr, and Sbi.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This invention discloses a production method for thin-gauge sulfuric acid dew point corrosion resistant steel. The hot-rolling production process is as follows: slab heating—high-pressure water descaling—width-fixed press—E1R1 roughing mill rolling—E2R2 roughing mill rolling—flying shear—high-pressure water descaling—F1F7 finishing mill rolling—intensive laminar flow cooling—coiling—warehousing—sampling and inspection—weighing and packaging; wherein: rolling is carried out using a traditional 2250 hot rolling production line; the slab heating temperature is 1270±20℃, the heating time is 150±20min, and hot continuous rolling is used; the finishing rolling temperature is 870±20℃, and the finished product thickness is 4mm; laminar flow cooling adopts pre-dispersive cooling, the cooling rate is 15-25℃ / s, and the steel strip temperature is reduced to 650±20℃ before coiling.

[0007] The chemical composition of the thin-gauge sulfuric acid dew point corrosion resistant steel is as follows (mass percentage): C: 0.06-0.08%; Si: 0.20-0.30%; Mn: 0.35-0.45%; P: ≤0.02%; S: ≤0.008%; Cu: 0.20-0.25%; Cr: 0.35-0.45%; Sb: 0.05-0.10%, with the remainder being Fe and impurities.

[0008] Furthermore, the rolling process is carried out using a traditional 2250 hot rolling production line; the slab heating temperature is 1270℃, the heating time is 150min, and the rolling is carried out using a hot continuous rolling mill; the finishing rolling temperature is 870℃, and the finished product thickness is 4mm; laminar flow cooling adopts pre-dispersion cooling, the cooling rate is 20℃ / s, and the steel strip temperature is reduced to 650℃ before coiling; finally, product performance testing is carried out.

[0009] Furthermore, the rolling process is carried out using a traditional 2250 hot rolling production line; the slab heating temperature is 1280℃, the heating time is 150min, and the rolling is carried out using a hot continuous rolling mill; the finishing rolling temperature is 878℃, and the finished product thickness is 4mm; laminar flow cooling adopts pre-dispersion cooling, the cooling rate is 18℃ / s, and the steel strip temperature is reduced to 653℃ before coiling; finally, product performance testing is carried out.

[0010] Furthermore, the rolling process is carried out using a traditional 2250 hot rolling production line; the slab heating temperature is 1279℃, the heating time is 150min, and the hot continuous rolling mill is used for rolling; the finishing rolling temperature is 890℃, and the finished product thickness is 4mm; laminar flow cooling adopts pre-dispersion cooling, the cooling rate is 19℃ / s, and the steel strip temperature is reduced to 644℃ before coiling; finally, product performance testing is carried out.

[0011] Furthermore, the chemical composition of the thin-gauge sulfuric acid dew point corrosion resistant steel is as follows (mass percentage): C: 0.07%; Si: 0.25%; Mn: 0.41%; P: 0.013%; S: 0.003%; Cu: 0.23%; Cr: 0.40%; Sb: 0.06%, with the remainder being Fe and impurities.

[0012] Furthermore, the chemical composition of the thin-gauge sulfuric acid dew point corrosion resistant steel is as follows (mass percentage): C: 0.07%; Si: 0.26%; Mn: 0.40%; P: 0.012%; S: 0.004%; Cu: 0.22%; Cr: 0.41%; Sb: 0.07%, with the remainder being Fe and impurities.

[0013] Furthermore, the chemical composition of the thin-gauge sulfuric acid dew point corrosion resistant steel is as follows (mass percentage): C: 0.07%; Si: 0.26%; Mn: 0.41%; P: 0.015%; S: 0.003%; Cu: 0.22%; Cr: 0.40%; Sb: 0.07%, with the remainder being Fe and impurities.

[0014] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0015] The metallographic microstructure of the steel grade of this invention is F+P. A thin-gauge sulfuric acid dew point corrosion-resistant steel produced using the method provided by this invention has been tested and found to meet relevant standards and user requirements in terms of mechanical and technological properties. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 This is a microstructure diagram of Embodiment 1 of the present invention. Detailed Implementation

[0018] The present invention will be described in more detail below through specific embodiments. These embodiments are merely descriptions of the best implementation of the invention and do not limit the scope of the invention in any way.

[0019] Example 1

[0020] Rolling was carried out using a conventional 2250 hot rolling production line. The slab was heated to 1270℃ for 150 minutes using a hot continuous rolling mill. The finishing rolling temperature was 870℃, and the finished product thickness was 4mm. Laminar flow cooling employed pre-dispersion cooling at a rate of 20℃ / s, reducing the strip temperature to 650℃ before coiling. Finally, product performance testing was conducted.

[0021] Example 2

[0022] Rolling was carried out using a conventional 2250 hot rolling production line. The slab was heated to 1280℃ for 150 minutes using a hot continuous rolling mill. The finishing rolling temperature was 878℃, and the finished product thickness was 4mm. Laminar flow cooling employed pre-dispersion cooling at a rate of 18℃ / s, reducing the strip temperature to 653℃ before coiling. Finally, product performance testing was conducted.

[0023] Example 3

[0024] Rolling was carried out using a conventional 2250 hot rolling production line. The slab was heated to 1279℃ for 150 minutes using a hot continuous rolling mill. The finishing rolling temperature was 890℃, and the finished product thickness was 4mm. Laminar flow cooling employed pre-dispersion cooling at a rate of 19℃ / s, reducing the strip temperature to 644℃ before coiling. Finally, product performance testing was conducted.

[0025] Comparative Example 1

[0026] The smelting was carried out in a laboratory furnace. The slab was heated to 1268℃ for 150 minutes and rolled using a hot continuous rolling mill. The finishing rolling temperature was 890℃, and the finished product thickness was 4mm. Laminar flow cooling was performed using pre-dispersion cooling at a rate of 19℃ / s, and the steel strip temperature was reduced to 655℃ before coiling. Finally, product performance testing was conducted.

[0027] Comparative Example 2

[0028] The smelting was carried out in a laboratory furnace. The slab was heated to 1260℃ for 150 minutes and rolled using a hot continuous rolling mill. The finishing rolling temperature was 890℃, and the finished product thickness was 4mm. Laminar flow cooling was performed using pre-dispersion cooling at a rate of 18℃ / s, and the strip temperature was reduced to 6480℃ before coiling. Finally, product performance testing was conducted.

[0029] The samples from the examples and comparative examples were tested for their resistance to sulfuric acid dew point corrosion. The specific sample dimensions and test methods met the requirements of the JB / T7901-2023 standard.

[0030] Table 1. Chemical composition (wt%) of Examples 1-3 of the present invention

[0031] chemical composition C Si Mn P S Cu Cr Sb Example 1 0.07 0.25 0.41 0.013 0.003 0.23 0.40 0.06 Example 2 0.07 0.26 0.40 0.012 0.004 0.22 0.41 0.07 Example 3 0.07 0.26 0.41 0.015 0.003 0.22 0.40 0.07 Comparative Example 1 0.10 0.35 0.63 0.013 0.003 0.25 0.35 0.05 Comparative Example 2 0.10 0.37 0.70 0.013 0.003 0.30 0.36 0.05

[0032] The mechanical properties of the steel coils in Examples 1 to 3 of the present invention were tested, and the test results are shown in Table 2.

[0033] Table 2 Mechanical properties of the steel coils in Examples 1-3 of the present invention

[0034] Product Performance <![CDATA[Yield strength R p0.2 / MPa]]> Tensile strength Rm / MPa Elongation A / % 180° cold bending test (b≥35mm) d=2a Average corrosion rate (mm / a) after 24 hours of full immersion in 20% sulfuric acid at 20℃. Average corrosion rate (mm / a) after 24 hours of full immersion in 50% sulfuric acid at 70℃. Example 1 323 438 31.5 qualified 1.08 58.90 Example 2 298 425 32.0 qualified 1.23 69.93 Example 3 311 451 29.5 qualified 1.12 61.33 Comparative Example 1 435 506 23.0 qualified 9.36 247.36 Comparative Example 2 396 521 22.0 qualified 8.98 243.87 Technical Agreement ≥265 ≥410 ≥22 qualified ≤10 ≤250

[0035] As shown in Table 2, the mechanical and technological properties of the high-strength weathering steel produced according to the method provided by this invention meet the requirements of the agreement signed with the user.

[0036] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for producing thin-gauge sulfuric acid dew point corrosion resistant steel, characterized in that: Hot rolling production process: slab heating—high-pressure water descaling—width-fixed press—E1R1 roughing mill rolling—E2R2 roughing mill rolling—flying shear—high-pressure water descaling—F1F7 finishing mill rolling—intensive laminar flow cooling—coiling—warehousing—sampling and inspection—weighing and packaging; wherein: rolling is carried out using a traditional 2250 hot rolling production line; slab heating temperature is 1270±20℃, heating time is 150±20min, and hot continuous rolling is used; finishing rolling temperature is 870±20℃, finished product thickness is 4mm; laminar flow cooling adopts pre-dispersive cooling, cooling rate is 15-25℃ / s, and the steel strip temperature is reduced to 650±20℃ before coiling; The chemical composition of the thin-gauge sulfuric acid dew point corrosion resistant steel is as follows (mass percentage): C: 0.06-0.08%; Si: 0.20-0.30%; Mn: 0.35-0.45%; P: ≤0.02%; S: ≤0.008%; Cu: 0.20-0.25%; Cr: 0.35-0.45%; Sb: 0.05-0.10%, with the remainder being Fe and impurities.

2. The method for producing thin-gauge sulfuric acid dew point corrosion resistant steel according to claim 1, characterized in that: Rolling is carried out using a traditional 2250 hot rolling production line; the slab heating temperature is 1270℃, the heating time is 150min, and hot continuous rolling is used; the finishing rolling temperature is 870℃, and the finished product thickness is 4mm; laminar flow cooling adopts pre-dispersion cooling, the cooling rate is 20℃ / s, and the steel strip temperature is reduced to 650℃ before coiling; finally, product performance testing is carried out.

3. The method for producing thin-gauge sulfuric acid dew point corrosion resistant steel according to claim 1, characterized in that: Rolling is carried out using a traditional 2250 hot rolling production line; the slab heating temperature is 1280℃, the heating time is 150min, and hot continuous rolling is used; the finishing rolling temperature is 878℃, and the finished product thickness is 4mm; laminar flow cooling adopts pre-dispersion cooling, the cooling rate is 18℃ / s, and the steel strip temperature is reduced to 653℃ before coiling; finally, product performance testing is carried out.

4. The method for producing thin-gauge sulfuric acid dew point corrosion resistant steel according to claim 1, characterized in that: Rolling is carried out using a traditional 2250 hot rolling production line; the slab heating temperature is 1279℃, the heating time is 150min, and the hot continuous rolling mill is used for rolling; the finishing rolling temperature is 890℃, and the finished product thickness is 4mm; laminar flow cooling adopts pre-dispersion cooling, the cooling rate is 19℃ / s, and the steel strip temperature is reduced to 644℃ before coiling; finally, product performance testing is carried out.

5. The method for producing thin-gauge sulfuric acid dew point corrosion resistant steel according to claim 2, characterized in that: The chemical composition (mass percentage) of the thin-gauge sulfuric acid dew point corrosion-resistant steel is: C: 0.07%; Si: 0.25%; Mn: 0.41%; P: 0.013%. S: 0.003%; Cu: 0.23%; Cr: 0.40%; Sb: 0.06%, with the remainder being Fe and impurities.

6. The method for producing thin-gauge sulfuric acid dew point corrosion resistant steel according to claim 3, characterized in that: The chemical composition (mass percentage) of the thin-gauge sulfuric acid dew point corrosion-resistant steel is: C: 0.07%; Si: 0.26%; Mn: 0.40%; P: 0.012%. S: 0.004%; Cu: 0.22%; Cr: 0.41%; Sb: 0.07%, with the remainder being Fe and impurities.

7. The method for producing thin-gauge sulfuric acid dew point corrosion resistant steel according to claim 4, characterized in that: The chemical composition (mass percentage) of the thin-gauge sulfuric acid dew point corrosion-resistant steel is: C: 0.07%; Si: 0.26%; Mn: 0.41%; P: 0.015%. S: 0.003%; Cu: 0.22%; Cr: 0.40%; Sb: 0.07%, with the remainder being Fe and impurities.

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