Preparation process of low-temperature corrosion-resisting steel

Abstract

The invention relates to the technical field of alloy steel, and provides a preparation process of low-temperature corrosion-resistant steel, which comprises the following steps: smelting, continuous casting, heating and hot rolling, hot rolling comprises rough rolling and finish rolling; water-based nano lubricating liquid needs to be used in the rough rolling process and the finish rolling process; the water-based nano lubricating liquid is prepared from the following components in percentage by weight: 0.7 to 1.6 percent of filler, 3 to 4.8 percent of additive and the balance of water, the filler comprises nano aluminum oxide; the nano aluminum oxide comprises nano aluminum oxide particles and flaky nano aluminum oxide in a mass ratio of (3-4): 1. By means of the technical scheme, the problem that in the prior art, low-temperature steel is insufficient in corrosion resistance is solved.

Description

Technical Field

[0001] This invention relates to the field of alloy steel technology, and more specifically, to a preparation process for low-temperature corrosion-resistant steel. Background Technology

[0002] When steel is used in environments with low temperatures, large temperature fluctuations, and complex corrosive media, more stringent requirements are placed on the comprehensive performance of the steel.

[0003] Extensive research has been conducted on low-temperature steels, but achieving a balance between low temperature and corrosion resistance remains challenging. During the billet rolling stage, a thick oxide scale (≥15μm) easily forms on the steel plate surface. This scale has poor adhesion to the steel matrix, a loose structure, and is prone to detachment. Subsequent pickling processes fail to completely remove this thick oxide scale, leaving residues on the steel plate surface. These residual oxide scales become corrosion initiation points during subsequent service, accelerating steel corrosion failure. Conventional rolling lubrication technologies cannot balance rolling efficiency with oxide scale control, making them unsuitable for the large-scale, high-quality production requirements of high-performance low-temperature steels. Summary of the Invention

[0004] This invention proposes a preparation process for low-temperature corrosion-resistant steel, which solves the problem of insufficient corrosion resistance of low-temperature steel in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a preparation process for low-temperature corrosion-resistant steel, comprising the following steps: smelting, continuous casting, heating, and hot rolling; The hot rolling includes roughing and finishing rolling; Water-based nano-lubricant is required during the roughing and finishing rolling processes. The water-based nano-lubricant is composed of the following components by weight percentage: 0.7%~1.6% filler, 3%~4.8% additives, and the balance being water; The filler includes nano-alumina; The nano-alumina includes nano-alumina particles and flake-shaped nano-alumina with a mass ratio of 3~4:1.

[0006] As a further technical solution, the additives include the following components in weight percentage: 1.4%~2.0% anionic dispersant, 0.6%~0.8% wetting agent, and 1%~2% polyethylene glycol.

[0007] As a further technical solution, the filler also includes nano-titanium dioxide.

[0008] As a further technical solution, the mass ratio of the nano-alumina to the nano-titanium dioxide is 1.5:0.8~1.

[0009] As a further technical solution, the particle size of the sheet-like nano-alumina is 3nm; The particle size of the nano-alumina particles is 20~30nm; The particle size of the nano-titanium dioxide is 10~15nm.

[0010] In the water-based nano-lubricant of this invention, 3nm-diameter flake-shaped nano-alumina can be more tightly arranged on the surface of the roll and the billet, forming a denser lubricating film and reducing the coefficient of friction. The larger-diameter nano-alumina particles can withstand a certain pressure under the rolling force to avoid breakage and ensure the continuity of rolling friction reduction. The 10-15nm-diameter nano-titanium dioxide fills the gaps between the nano-alumina particles, enhancing the overall stability and uniformity of the lubricating film, reducing the contact between the billet and oxygen, and preventing the formation of oxide scale, thereby giving the final steel plate excellent corrosion resistance.

[0011] As a further technical solution, the hot rolling also includes descaling, cooling, and coiling.

[0012] As a further technical solution, the casting temperature during the continuous casting process is 1450~1550℃, and the casting speed is 0.9~1.2m / min.

[0013] As a further technical solution, the heating temperature is 1150~1250℃, and the time is 2~4h.

[0014] As a further technical solution, the initial rolling temperature of the roughing mill is 1120~1150℃, the final rolling temperature is 1050~1080℃, the roughing mill is rolled in 3~5 passes, and the cumulative reduction rate is ≥50%.

[0015] As a further technical solution, the initial rolling temperature of the finishing mill is 950~1000℃, the final rolling temperature is 800~820℃, the finishing mill is rolled in 4~6 passes, and the cumulative reduction rate is ≥60%.

[0016] As a further technical solution, the anionic dispersant includes one of sodium polyacrylate and ammonium polyacrylate.

[0017] As a further technical solution, the wetting agent includes sodium dodecylbenzenesulfonate.

[0018] As a further technical solution, the descaling pressure is 20~25MPa.

[0019] As a further technical solution, during the cooling process, the temperature of the laminar water is 25~30℃, and the cooling rate is 15~25℃ / s.

[0020] As a further technical solution, the winding temperature is 550~650℃.

[0021] As a further technical solution, the preparation method of the water-based nano-lubricant includes the following steps: Polyethylene glycol is added to water and mixed, and then anionic dispersant, wetting agent and filler are added in sequence and mixed evenly to obtain water-based nano lubricant.

[0022] The present invention also proposes a low-temperature corrosion-resistant steel, which is prepared by the aforementioned preparation process; The low-temperature corrosion-resistant steel is composed of the following components by mass percentage: C 0.04%~0.08%, Si 0.5%~0.8%, Mn 1.5%~2.0%, P ≤0.008%, S 0.005%~0.008%, Ni 0.1%~0.3%, Cr 0.3%~0.8%, Nb 0.06%~0.12%, Cu 0.2%~0.5%, with the balance being Fe and other unavoidable impurities.

[0023] The working principle and beneficial effects of this invention are as follows: In this invention, nano-alumina particles and flake-shaped nano-alumina are used in combination as fillers in a water-based nano-lubricant. The nano-alumina particles roll like ball bearings during rolling, effectively reducing sliding friction and lowering the rolling friction coefficient. The flake-shaped nano-alumina forms relative sliding parallel to the rolls and the steel billet, further reducing the friction coefficient and ultimately significantly improving the corrosion resistance of the steel. Furthermore, both are alumina with consistent density and surface properties, making them more stable within the same system. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In the following examples and comparative examples, the polyethylene glycol is PEG-200.

[0026] Example 1 A low-temperature corrosion-resistant steel is composed of the following components in weight percentage: C 0.04%, Si 0.5%, Mn 1.5%, P 0.005%, S 0.005%, Ni 0.1%, Cr 0.3%, Nb 0.06%, Cu 0.2%, with the balance being Fe and other unavoidable impurities; A process for preparing a low-temperature corrosion-resistant steel includes the following steps: The raw materials are melted to obtain molten steel. The molten steel is then cast at 1450℃ and pulled at 0.9 m / min to obtain a continuously cast billet. The billet is heated to 1150℃ and held for 4 hours. Descaling is performed at 20 MPa, and then it enters the rough rolling stage. The rough rolling starts at 1120℃, is rolled in 3 passes, with a cumulative reduction of 50%, and a final rolling temperature of 1050℃. Descaling is then performed again at 20 MPa, and the billet enters the finish rolling stage. The finish rolling starts at 950℃, is rolled in 4 passes, with a cumulative reduction of 60%, and a final rolling temperature of 800℃. Water-based nano-lubricant is used during the rough rolling and finish rolling processes. The billet is then cooled in laminar water at 25℃ with a cooling rate of 15℃ / s. Finally, it is coiled at 550℃ to obtain low-temperature corrosion-resistant steel. The water-based nano-lubricant is composed of the following components by weight percentage: 0.7% filler, 1.4% sodium polyacrylate, 0.6% sodium dodecylbenzenesulfonate, 1% polyethylene glycol, and the balance being water; The filler consists of nano-alumina particles (40 nm in diameter) and flake-shaped nano-alumina (3 nm in diameter) in a mass ratio of 3:1. The preparation method of water-based nano-lubricating fluid includes the following steps: Polyethylene glycol was added to water and mixed evenly. Then, sodium polyacrylate, sodium dodecylbenzene sulfonate and filler were added in sequence and mixed evenly again to obtain a water-based nano lubricant.

[0027] Example 2 A low-temperature corrosion-resistant steel is composed of the following components in weight percentage: C 0.08%, Si 0.8%, Mn 2.0%, P 0.008%, S 0.008%, Ni 0.3%, Cr 0.8%, Nb 0.12%, Cu 0.5%, with the balance being Fe and other unavoidable impurities; A process for preparing a low-temperature corrosion-resistant steel includes the following steps: The raw materials are melted to obtain molten steel. The molten steel is then cast at 1550℃ and pulled at 1.2 m / min to obtain a continuously cast billet. The billet is heated to 1250℃ and held for 2 hours. Descaling is performed at 25 MPa, and then it enters the rough rolling stage. The rough rolling starts at 1150℃, is rolled in 5 passes, with a cumulative reduction of 60%, and a final rolling temperature of 1080℃. Descaling is then performed again at 25 MPa, and the billet enters the finish rolling stage. The finish rolling starts at 1000℃, is rolled in 6 passes, with a cumulative reduction of 75%, and a final rolling temperature of 820℃. Water-based nano-lubricant is used during the rough rolling and finish rolling processes. The billet is then cooled in a laminar flow at 30℃ at a cooling rate of 25℃ / s. Finally, it is coiled at 650℃ to obtain low-temperature corrosion-resistant steel. The water-based nano-lubricant is composed of the following components by weight percentage: 1.6% filler, 2.0% ammonium polyacrylate, 0.8% sodium dodecylbenzenesulfonate, 2% polyethylene glycol, and the balance being water; The filler consists of nano-alumina particles (40 nm in diameter) and flake-shaped nano-alumina (3 nm in diameter) in a mass ratio of 3:1. The preparation method of water-based nano-lubricating fluid includes the following steps: Polyethylene glycol was added to water and mixed evenly. Then, ammonium polyacrylate, sodium dodecylbenzene sulfonate and filler were added in sequence and mixed evenly again to obtain a water-based nano-lubricant.

[0028] Example 3 A low-temperature corrosion-resistant steel is composed of the following components in weight percentage: C 0.06%, Si 0.7%, Mn 1.8%, P 0.004%, S 0.006%, Ni 0.2%, Cr 0.55%, Nb 0.09%, Cu 0.35%, with the balance being Fe and other unavoidable impurities; A process for preparing a low-temperature corrosion-resistant steel includes the following steps: The raw materials are melted to obtain molten steel. The molten steel is then cast at 1500℃ and pulled at 1.1 m / min to obtain a continuously cast billet. The billet is heated to 1200℃ and held for 3 hours. Descaling is performed at 25 MPa, and then it enters the roughing rolling stage. The roughing rolling starts at 1130℃, is rolled in 4 passes, with a cumulative reduction of 55%, and a final rolling temperature of 1060℃. Descaling is then performed again at 25 MPa, and the billet enters the finishing rolling stage. The finishing rolling starts at 970℃, is rolled in 5 passes, with a cumulative reduction of 65%, and a final rolling temperature of 810℃. Water-based nano-lubricant is used during the roughing and finishing rolling processes. The billet is then cooled in laminar water at 25℃ with a cooling rate of 20℃ / s. Finally, it is coiled at 600℃ to obtain low-temperature corrosion-resistant steel. The water-based nano-lubricant is composed of the following components by weight percentage: 1.3% filler, 1.6% sodium polyacrylate, 0.7% sodium dodecylbenzenesulfonate, 1.4% polyethylene glycol, and the balance being water; The filler consists of nano-alumina particles (40 nm in diameter) and flake-shaped nano-alumina (3 nm in diameter) in a mass ratio of 3:1. The preparation method of water-based nano-lubricating fluid includes the following steps: Polyethylene glycol was added to water and mixed evenly. Then, sodium polyacrylate, sodium dodecylbenzene sulfonate and filler were added in sequence and mixed evenly again to obtain a water-based nano lubricant.

[0029] Example 4 The only difference between this embodiment and Embodiment 3 is that the filler is nano-alumina particles (40 nm in diameter) with a mass ratio of 3.5:1 and flake-shaped nano-alumina (3 nm in diameter).

[0030] Example 5 The only difference between this embodiment and Embodiment 3 is that the filler is nano-alumina particles (40nm in diameter) with a mass ratio of 4:1 and sheet-like nano-alumina (3nm in diameter).

[0031] Example 6 The only difference between this embodiment and Example 4 is that the filler is nano-alumina and nano-titanium dioxide with a mass ratio of 1.5:0.8 (particle size of 20nm). The nano-alumina consists of nano-alumina particles (40 nm in diameter) in a mass ratio of 4:1 and flake-shaped nano-alumina (3 nm in diameter).

[0032] Example 7 The only difference between this embodiment and Example 4 is that the filler is nano-alumina and nano-titanium dioxide (particle size of 20nm) with a mass ratio of 1.5:1. The nano-alumina consists of nano-alumina particles (40 nm in diameter) in a mass ratio of 4:1 and flake-shaped nano-alumina (3 nm in diameter).

[0033] Example 8 The only difference between this embodiment and Embodiment 7 is that the particle size of the nano-alumina particles is 30 nm, and the particle size of the nano-titanium dioxide particles is 15 nm.

[0034] Example 9 The only difference between this embodiment and Embodiment 7 is that the particle size of the nano-alumina particles is 20 nm, and the particle size of the nano-titanium dioxide particles is 10 nm.

[0035] Example 10 The only difference between this embodiment and Embodiment 7 is that the particle size of the nano-alumina particles is 10 nm, and the particle size of the nano-titanium dioxide particles is 5 nm.

[0036] Comparative Example 1 The only difference between this comparative example and Example 3 is that the filler is nano-alumina particles.

[0037] Comparative Example 2 The only difference between this comparative example and Example 3 is that the filler is flaky nano-alumina.

[0038] Experimental Example 1 The corrosion resistance of the low-temperature corrosion-resistant steels prepared in Examples 1-10 and Comparative Examples 1-2 was tested according to the test method specified in GB / T 19746-2018 "Corrosion Salt Solution Immersion Test of Metals and Alloys" for 20 days. The coefficient of friction was obtained according to the test method specified in GB / T 12583-1998 "Determination of Extreme Pressure Properties of Lubricants (Four-Ball Method)" with a friction load of 100 N and a rotation speed of 800 rpm. The test results are shown in Table 1: Table 1. Performance test results of the low-temperature corrosion-resistant steels prepared in Examples 1-10 and Comparative Examples 1-2

[0039] 1. Compared with Comparative Examples 1 and 2, the corrosion rate of the low-temperature corrosion-resistant steel prepared in Examples 1 to 10 was significantly lower than that in Comparative Examples 1 and 2. This indicates that when nano-alumina particles and flake nano-alumina are used in combination in the water-based nano-lubricant used in the roughing and finishing rolling stages, the low-temperature corrosion-resistant steel exhibits excellent corrosion resistance.

[0040] 2. The water-based nano-lubricants prepared in Examples 1-10 have a friction coefficient ≤0.1 during rolling, which is lower than that of Comparative Examples 2-2. This indicates that when nano-alumina particles and flake nano-alumina are used in combination in the water-based nano-lubricant used in the roughing and finishing stages, the rolling friction coefficient is even lower.

[0041] 3. Compared with Examples 3 to 5, the corrosion rate of the low-temperature corrosion-resistant steel prepared in Example 4 is lower than that in Examples 3 and 5, indicating that when the filler in the water-based nano lubricant is nano alumina particles and flake nano alumina in a mass ratio of 3.5:1, the corrosion resistance of the low-temperature corrosion-resistant steel can be improved.

[0042] 4. Compared with Examples 4 and 6-10, the corrosion rate of the low-temperature corrosion-resistant steel prepared in Examples 8-9 is lower than that in Examples 4, 6-7 and 10. This indicates that when the particle size of the flake-shaped nano-alumina is 3nm, the particle size of the nano-alumina particles is 20-30nm, and the particle size of the nano-titanium dioxide is 10-15nm, the corrosion resistance of the low-temperature corrosion-resistant steel is further improved.

[0043] Experimental Example 2 The low-temperature corrosion-resistant steels prepared in Examples 1-3 were tested for their low-temperature performance according to the method specified in GB / T 229-2020 "Metallic Materials - Charpy Pendulum Impact Test Method". The test results are shown in Table 2. Table 2. Low-temperature properties of the low-temperature corrosion-resistant steels prepared in Examples 1-3

[0044] The low-temperature corrosion-resistant steels prepared in Examples 1-3 were subjected to mechanical property tests at a low temperature of -50℃. The transverse impact energy was 149-153J, indicating that the prepared steels have excellent low-temperature toughness.

[0045] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for preparing low-temperature corrosion-resistant steel, characterized in that, Includes the following steps: Smelting, continuous casting, heating, and hot rolling; The hot rolling includes roughing and finishing rolling; Water-based nano-lubricant is required during the roughing and finishing rolling processes. The water-based nano-lubricant is composed of the following components by weight percentage: 0.7%~1.6% filler, 3%~4.8% additives, and the balance being water; The filler includes nano-alumina; The nano-alumina includes nano-alumina particles and flake-shaped nano-alumina with a mass ratio of 3~4:

1.

2. The preparation process of a low-temperature corrosion-resistant steel according to claim 1, characterized in that, The additives comprise the following components by weight percentage: 1.4% to 2.0% anionic dispersant, 0.6% to 0.8% wetting agent, and 1% to 2% polyethylene glycol.

3. The preparation process of a low-temperature corrosion-resistant steel according to claim 1, characterized in that, The filler also includes nano-titanium dioxide; The mass ratio of nano-alumina to nano-titanium dioxide is 1.5:0.8~1.

4. The preparation process of a low-temperature corrosion-resistant steel according to claim 3, characterized in that, The particle size of the sheet-like nano-alumina is 3 nm; The particle size of the nano-alumina particles is 20~30nm; The particle size of the nano-titanium dioxide is 10~15nm.

5. The preparation process of a low-temperature corrosion-resistant steel according to claim 1, characterized in that, The hot rolling process also includes descaling, cooling, and coiling.

6. The preparation process of a low-temperature corrosion-resistant steel according to claim 1, characterized in that, The casting temperature during the continuous casting process is 1450~1550℃, and the casting speed is 0.9~1.2m / min; The heating temperature is 1150~1250℃, and the time is 2~4 hours; The initial rolling temperature of the roughing mill is 1120~1150℃, the final rolling temperature is 1050~1080℃, the roughing mill is rolled in 3~5 passes, and the cumulative reduction rate is ≥50%; The initial rolling temperature of the finishing mill is 950~1000℃, the final rolling temperature is 800~820℃, the finishing mill is rolled in 4~6 passes, and the cumulative reduction rate is ≥60%.

7. The preparation process of a low-temperature corrosion-resistant steel according to claim 2, characterized in that, The anionic dispersant includes one of sodium polyacrylate and ammonium polyacrylate; The wetting agent includes sodium dodecylbenzenesulfonate.

8. The preparation process of a low-temperature corrosion-resistant steel according to claim 5, characterized in that, The descaling pressure is 20~25MPa; During the cooling process, the temperature of the laminar water is 25~30℃, and the cooling rate is 15~25℃ / s; The winding temperature is 550~650℃.

9. The preparation process of a low-temperature corrosion-resistant steel according to claim 2, characterized in that, The preparation method of the water-based nano-lubricating fluid includes the following steps: Polyethylene glycol is added to water and mixed, and then anionic dispersant, wetting agent and filler are added in sequence and mixed evenly to obtain water-based nano lubricant.

10. A low-temperature corrosion-resistant steel, characterized in that, Prepared by the preparation process described in any one of claims 1 to 9; The low-temperature corrosion-resistant steel is composed of the following components by mass percentage: C 0.04%~0.08%, Si 0.5%~0.8%, Mn 1.5%~2.0%, P ≤0.008%, S 0.005%~0.008%, Ni 0.1%~0.3%, Cr 0.3%~0.8%, Nb 0.06%~0.12%, Cu 0.2%~0.5%, with the balance being Fe and other unavoidable impurities.

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