Manufacturing method of hot-rolled H-shaped steel for ocean engineering structure

Abstract

The invention discloses a manufacturing method of hot-rolled H-shaped steel for an ocean engineering structure, which is used for successfully manufacturing the hot-rolled H-shaped steel for the ocean engineering structure by controlling rolling processes such as special-shaped blank heating, rough rolling, finish rolling, cooling and the like. The steel comprises the following chemical components in percentage by mass: 0.06%-0.20% of C, 0.10%-0.50% of Si, 1.00%-1.60% of Mn, less than or equal to 0.030% of P, less than or equal to 0.030% of S, 0.010%-0.050% of Nb, 0.04%-0.10% of V and the balance of Fe and inevitable impurities, and the total mass fraction is 100%. By optimizing the chemical components and accurately controlling the rolling process, the produced hot-rolled H-shaped steel has good yield strength, tensile strength and ductility, meanwhile has excellent low-temperature impact toughness, and is particularly suitable for meeting the requirements of complex environments of ocean engineering.

Description

Technical Field

[0001] The present invention belongs to the technical field of rolling, and particularly relates to a manufacturing method of hot-rolled H-beams for offshore engineering structures. Background Art

[0002] The H-beams for offshore engineering have broad prospects for future popularization and application. Especially in the context of global offshore resource development and the construction of green energy such as offshore wind power, the demand is continuously increasing. H-beams possess excellent strength, corrosion resistance, and fatigue resistance, and are suitable for the harsh conditions of the marine environment. By optimizing the composition design, controlling the production process, and surface treatment, the service life and reliability of the steel can be significantly improved. At the same time, with the continuous progress of domestic and foreign steel technologies and the increasing demand for high-performance structural materials, the H-beams for offshore engineering have great application potential in fields such as large offshore platforms and submarine pipeline support structures, and are expected to promote the technological upgrading of steel mills and the high value-added of products. A steel mill organized technical research based on its own technical equipment characteristics and successfully developed hot-rolled H-beams for offshore engineering structures.

[0003] Literature 1 (Development and Research of H-Beams for Offshore Oil Platforms - Gu Jianguo) introduces the domestic and foreign development overview, performance requirements, production process technologies of H-beams for offshore oil platforms, as well as the production process route, key process measures, controlled composition, and physical quality of the development of such H-beams by Magang, and conducts relevant discussions and summaries. This patent introduces a hot-rolled H-beam for offshore engineering structures and its manufacturing method, introduces its chemical composition, and manufactures H-beams that meet the requirements of offshore engineering through processes such as heating of special-shaped billets, rough rolling, finish rolling, and cooling. This patent focuses on the manufacturing method and performance improvement of hot-rolled H-beams for offshore engineering structures. Through more refined process control (such as chemical composition, parameters of each link) and the setting of ratios, it can better ensure the comprehensive mechanical properties and quality stability of H-beams, and better meet the usage requirements of offshore engineering structures.

[0004] Literature 2 (Optimization of the Production Process of Hot-Rolled H-Beams for Offshore Oil Platforms - Sun Wei, Wang Kaizhong) analyzes the factors affecting the transverse low-temperature impact toughness of hot-rolled H-beams for offshore oil platforms through industrial tests, including aspects such as smelting, continuous casting, and controlled rolling processes. On this basis, the production process is optimized to make the product meet the requirements, and the physical quality of the product is also introduced. This patent introduces a hot-rolled H-beam for offshore engineering structures and its manufacturing method, introduces its chemical composition, and manufactures H-beams that meet the requirements of offshore engineering through processes such as heating of special-shaped billets, rough rolling, finish rolling, and cooling.

[0005] Document 3 (Publication No. CN103556055A) provides a hot-rolled section steel for the structure of an offshore natural gas production platform and its production method, including its chemical composition. Through processes such as converter smelting and refining, various process parameters and different example situations are introduced, and the product meets the relevant technical requirements. This patent focuses on the manufacturing method and performance improvement of hot-rolled H-section steel for offshore engineering structures. Through more refined process control (such as chemical composition and parameters of each link) and the setting of ratios, it can better ensure the comprehensive mechanical properties and quality stability of the H-section steel, and better meet the usage requirements of offshore engineering structures. Summary of the Invention

[0006] The object of the present invention is to provide a manufacturing method of hot-rolled H-section steel for offshore engineering structures. By optimizing the chemical composition and precisely controlling the rolling process, the hot-rolled H-section steel produced by the present invention has good yield strength, tensile strength and elongation, and at the same time has excellent low-temperature impact toughness, and is particularly suitable for the requirements of complex offshore engineering environments.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A manufacturing method of hot-rolled H-section steel for offshore engineering structures of the present invention, its rolling production includes: heating of the special-shaped billet, rough rolling, finish rolling, and cooling; among them:

[0009] Heating of the special-shaped billet: When heating the special-shaped billet, ensure that the atmosphere in the heating furnace is a reducing atmosphere, the temperature in the preheating section ≤ 890 °C, the heating section 1 ≤ 1050 °C, the temperature in the heating section 2 is controlled at 1100 - 1200 °C, and the soaking section temperature is controlled at 1200 - 1260 °C, and the total heating time is 2.5 - 3.2 h;

[0010] Rough rolling: Before the billet enters BD1, high-pressure water descaling is carried out to remove the scale on the surface of the billet to ensure the smooth surface of the finished product. The rolling temperature of the BD1 blooming mill is 1130 - 1180 °C, rolling 5 passes, and the reduction ratio ≥ 50%;

[0011] Finish rolling: The rolling temperature of the CCS universal mill is 900 - 1000 °C, rolling 7 passes, carrying out controlled rolling, and the finish rolling temperature is 850 - 890 °C.

[0012] Cooling: The finished H-section steel is densely arranged on the cooling bed for cooling, and the temperature on the cooling bed ≥ 800 °C;

[0013] The mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.06% - 0.20%, Si 0.10% - 0.50%, Mn 1.00% - 1.60%, P ≤ 0.030%, S ≤ 0.030%, Nb 0.010% - 0.050%, V 0.04 - 0.10%, and the rest is Fe and inevitable impurities, with the total mass fraction being 100%.

[0014] Furthermore, the finished product size of the H-beam is H700mm × 300mm × 13mm × 24mm.

[0015] Furthermore, the mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.10%, Si 0.21%, Mn 1.38%, P 0.015, S 0.008%, Nb 0.037%, V 0.055%, and the rest is Fe and inevitable impurities, with the total mass fraction being 100%.

[0016] Furthermore, the mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.09%, Si 0.20%, Mn 1.36%, P 0.014%, S 0.007%, Nb 0.039%, V 0.065%, and the rest is Fe and inevitable impurities, with the total mass fraction being 100%.

[0017] Furthermore, the mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.08%, Si 0.22%, Mn 1.35%, P 0.013%, S 0.006%, Nb 0.041%, V 0.060%, and the rest is Fe and inevitable impurities, with the total mass fraction being 100%.

[0018] Furthermore, the mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.09%, Si 0.19%, Mn 1.37%, P 0.015%, S 0.008%, Nb 0.040%, V 0.068%, and the rest is Fe and inevitable impurities, with the total mass fraction being 100%.

[0019] Furthermore, this method effectively improves the comprehensive mechanical properties of the steel and improves the low-temperature properties.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0021] (1) By optimizing the chemical components and precisely controlling the rolling process, the hot-rolled H-beam produced by the present invention has good yield strength, tensile strength, and elongation, and at the same time has excellent low-temperature impact toughness, which is particularly suitable for the requirements of the complex environment of offshore engineering.

[0022] (2) The use of processes such as heating of special-shaped billets, high-pressure water descaling and temperature-controlled rolling can greatly reduce surface defects, making the surface defect rate of H-shaped steel less than 2%, thereby improving the stability of product quality and surface finish.

[0023] (3) By precisely controlling the process parameters of heating, rough rolling, finishing rolling and cooling, the present invention can ensure the consistency of product performance and is suitable for large-scale production, thereby improving production efficiency and yield rate. DETAILED DESCRIPTION

[0024] Embodiment 1:

[0025] When heating the special-shaped blanks, ensure that the heating furnace is in a reducing atmosphere, the temperature of the preheating section is ≤890℃, the temperature of the first heating section is ≤1050℃, the temperature of the second heating section is controlled at 1100-1200℃, the temperature of the soaking section is controlled at 1235℃, and the total heating time is 2.9h.

[0026] Before the ingot enters BD1, high-pressure water descaling is carried out to remove the iron oxide scale on the surface of the ingot to ensure the surface of the finished product is smooth. The starting rolling temperature of BD1 ingot mill is 1140℃, and the rolling is 5 times with a reduction rate of ≥50%.

[0027] The CCS universal rolling mill starts rolling at 925°C, rolls for 7 passes, performs temperature-controlled rolling, and the final rolling temperature is 870°C.

[0028] Embodiment 2:

[0029] When heating the special-shaped blanks, ensure that the heating furnace is in a reducing atmosphere, the preheating section temperature is ≤890°C, the first heating section temperature is ≤1050°C, the second heating section temperature is controlled at 1100-1200°C, the soaking section temperature is controlled at 1245°C, and the total heating time is 3.0h.

[0030] Before the ingot enters BD1, high-pressure water descaling is carried out to remove the iron oxide scale on the surface of the ingot to ensure the smooth surface of the finished product. The rolling temperature of BD1 ingot mill is 1150℃, and the rolling is 5 times with a reduction rate of ≥50%.

[0031] The CCS universal rolling mill starts rolling at a temperature of 935°C, performs 7 passes, performs temperature-controlled rolling, and the final rolling temperature is 865°C.

[0032] Embodiment 3:

[0033] When heating the special-shaped blanks, ensure that the heating furnace is in a reducing atmosphere, the temperature of the preheating section is ≤890℃, the temperature of the first heating section is ≤1050℃, the temperature of the second heating section is controlled at 1100-1200℃, the temperature of the soaking section is controlled at 1255℃, and the total heating time is 2.8h.

[0034] Before the billet enters BD1, high-pressure water descaling is carried out to remove the scale on the surface of the billet to ensure the smooth surface of the finished product. The rolling temperature of the BD1 blooming mill is 1160°C, and it is rolled for 5 passes with a reduction ratio of ≥50%.

[0035] The rolling temperature of the CCS universal mill is 945°C, and it is rolled for 7 passes with controlled rolling, and the final rolling temperature is 875°C.

[0036] Example 4:

[0037] When heating the special-shaped billet, ensure that the atmosphere in the heating furnace is a reducing atmosphere. The temperature in the preheating section is ≤890°C, the first heating section is ≤1050°C, the temperature in the second heating section is controlled at 1100 - 1200°C, the soaking section temperature is controlled at 1265°C, and the total heating time is 3.2 h.

[0038] Before the billet enters BD1, high-pressure water descaling is carried out to remove the scale on the surface of the billet to ensure the smooth surface of the finished product. The rolling temperature of the BD1 blooming mill is 1170°C, and it is rolled for 5 passes with a reduction ratio of ≥50%.

[0039] The rolling temperature of the CCS universal mill is 955°C, and it is rolled for 7 passes with controlled rolling, and the final rolling temperature is 885°C.

[0040] Comparative Example 1:

[0041] Except that the V content is reduced and it is different from Example 1, the rest of Comparative Example 1 is exactly the same as Example 1. The V content in this comparative example is 0.030%.

[0042] Comparative Example 2:

[0043] Except that the Mn content is reduced and it is different from Example 1, the rest of Comparative Example 2 is exactly the same as Example 1. The Mn content in this comparative example is 0.90%.

[0044] Comparative Example 3:

[0045] Except that the final rolling temperature is increased and it is different from Example 1, the rest of Comparative Example 3 is exactly the same as Example 1. The final rolling temperature in this comparative example is 920°C.

[0046] Comparative Example 4:

[0047] Except that no Nb element is added and it is different from Example 1, the rest of Comparative Example 4 is exactly the same as Example 1.

[0048] Check the surface quality of the finished AH40 hot-rolled H-beam for offshore engineering structures, and at the same time test its mechanical properties.

[0049] No obvious surface quality defects were found during the inspection. The finished product has good quality. The rolling defect rate of the finished product surface is less than 2%. The performance of the H-beam after rolling meets the standard requirements. Table 1 shows the chemical compositions of various steel grades. Tables 2 and 3 further illustrate the present invention in combination with the embodiments.

[0050] Table 1 Chemical Compositions of Each Example (Mass Percent / %)

[0051] Example C Si Mn P S Nb V Example 1 0.10 0.21 1.38 0.015 0.008 0.037 0.055 Example 2 0.09 0.20 1.36 0.014 0.007 0.039 0.065 Example 3 0.08 0.22 1.35 0.013 0.006 0.041 0.060 Example 4 0.09 0.19 1.37 0.015 0.008 0.040 0.068 Comparative Example 1 0.11 0.21 1.42 0.016 0.009 0.039 0.030 Comparative Example 2 0.09 0.19 0.90 0.015 0.007 0.037 0.058 Comparative Example 3 0.10 0.23 1.38 0.014 0.008 0.041 0.057 Comparative Example 4 0.11 0.21 1.39 0.014 0.009 —— 0.058

[0052] Table 2 Heating and Rolling Control of Each Example

[0053]

[0054] Table 3 Mechanical Properties of Rolled H-beams of Each Example

[0055]

[0056]

[0057] As can be seen from Tables 1 - 3, through the above comparative examples, we can clearly see the advantages of the embodiments in chemical composition design and process control. Compared with these comparative examples, the embodiments perform better in terms of strength, toughness, especially low-temperature impact toughness, which is attributed to the precise control of key alloying elements (such as vanadium, manganese, niobium) and the careful adjustment of heating and rolling processes.

[0058] It can be seen from the above examples and comparative examples that: (1) Compared with the examples, the vanadium content in Comparative Example 1 was reduced (0.03%), which significantly affected the strength and low-temperature impact toughness of the steel. The experimental data showed that the lower vanadium content led to a significant decrease in the tensile strength and impact toughness, especially poor performance at low temperatures. This indicates that controlling the vanadium content within the range of 0.05% - 0.10% can significantly improve the comprehensive mechanical properties of the steel, especially the low-temperature toughness. (2) Compared with the examples, after the manganese content in Comparative Example 2 was reduced to 0.90%, the strength and toughness decreased significantly, especially the yield strength and low-temperature impact energy were significantly insufficient. As an element to enhance strength, insufficient manganese content will lead to strength loss. Controlling the manganese content within the range of 1.10% - 1.60% in the examples can ensure high strength and good low-temperature toughness. (3) Compared with the examples, the finish rolling temperature in Comparative Example 3 was increased to 920 °C, and the results showed that the mechanical properties decreased, especially the low-temperature toughness was poor. Controlling the finish rolling temperature within the range of 850 - 890 °C can effectively maintain the strength and toughness of the steel, which is the optimal temperature range obtained through a large number of experiments. (4) In Comparative Example 4, the niobium element was removed, and the results showed that the yield strength and low-temperature toughness were significantly insufficient. Niobium, as a fine grain strengthening element, is crucial for improving the strength and toughness of the steel. The addition of niobium in the examples effectively improved the comprehensive mechanical properties of the steel and improved the low-temperature performance.

[0059] The above-described examples are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A manufacturing method of hot-rolled H-shaped steel for ocean engineering structures, and its rolling production includes: Heating, rough rolling, finish rolling, and cooling of the special-shaped bloom; characterized in that: Heating of the special-shaped bloom: When heating the special-shaped bloom, ensure a reducing atmosphere in the heating furnace. The temperature in the preheating section is ≤890°C, in the first heating section is ≤1050°C, the temperature in the second heating section is controlled at 1100 - 1200°C, and the soaking section temperature is controlled at 1200 - 1260°C. The total heating time is 2.5 - 3.2 h; Rough rolling: High-pressure water descaling is carried out before the billet enters BD1 to remove the scale on the surface of the billet to ensure a smooth surface of the finished product. The rolling temperature of the BD1 blooming mill is 1130 - 1180°C, rolling 5 passes, and the reduction ratio is ≥50%; Finish rolling: The rolling temperature of the CCS universal mill is 900 - 1000°C, rolling 7 passes, and controlled rolling is carried out. The finish rolling temperature is 850 - 890°C. Cooling: The finished H-beam is densely arranged on the cooling bed for cooling, and the temperature when entering the cooling bed is ≥800°C; The mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.06% - 0.20%, Si 0.10% - 0.50%, Mn 1.00% - 1.60%, P ≤ 0.030%, S ≤ 0.030%, Nb 0.010% - 0.050%, V 0.04 - 0.10%, and the rest are Fe and inevitable impurities, with the total mass fraction being 100%.

2. The manufacturing method of the hot-rolled H-shaped steel for ocean engineering structures according to claim 1, characterized in that, The finished size of the H-beam is H700mm×300mm×13mm×24mm.

3. The manufacturing method of the hot-rolled H-shaped steel for offshore engineering structures according to claim 1, characterized in that, The mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.10%, Si 0.21%, Mn 1.38%, P 0.015, S 0.008%, Nb 0.037%, V 0.055%, and the rest are Fe and inevitable impurities, with the total mass fraction being 100%.

4. The manufacturing method of the hot-rolled H-shaped steel for offshore engineering structures according to claim 1, characterized in that, The mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.09%, Si 0.20%, Mn 1.36%, P 0.014%, S 0.007%, Nb 0.039%, V 0.065%, and the rest are Fe and inevitable impurities, with the total mass fraction being 100%.

5. The manufacturing method of the hot-rolled H-shaped steel for offshore engineering structures according to claim 1, characterized in that, The mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.08%, Si 0.22%, Mn 1.35%, P 0.013%, S 0.006%, Nb 0.041%, V 0.060%, and the rest are Fe and inevitable impurities, with the total mass fraction being 100%.

6. The manufacturing method of the hot-rolled H-shaped steel for ocean engineering structures according to claim 1, characterized in that, The mass percentages of the chemical components of the hot-rolled H-beam for offshore engineering structures include: C 0.09%, Si 0.19%, Mn 1.37%, P 0.015%, S 0.008%, Nb 0.040%, V 0.068%, and the rest are Fe and inevitable impurities, with the total mass fraction being 100%.

7. The manufacturing method of the hot-rolled H-shaped steel for ocean engineering structures according to claim 1, characterized in that, This method effectively improves the comprehensive mechanical properties of the steel and improves the low-temperature properties.

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