Corrosion-resistant alloy reinforcing steel and its manufacturing method

Abstract

The present application provides a corrosion-resistant alloy rebar and a manufacturing method thereof. The corrosion-resistant alloy rebar contains 0.05-0.25% by weight of C, 1.05-2% by weight of Si, 0.3-1.5% by weight of Mn, 0.5-2.5% by weight of Cr, 0.05-1% by weight of Ni, 0.001-0.005% by weight of O, 0.001-0.0035% by weight of S, 0.005-0.1% by weight of Ti, 0.005-0.1% by weight of Al, 0.005-0.03% by weight of V, and 0.005-0.03% by weight of Nb, with the balance being Fe and unavoidable impurities. The manufacturing method thereof includes the steps of smelting, refining, continuous casting, rolling, and cooling, which are performed in sequence. The present invention uses elements such as Si, Ti, Al, and Mn to compensate for the decrease in corrosion resistance caused by the decrease in Cr content, thereby significantly reducing the production costs of corrosion-resistant alloy rebars.

Description

Cross-reference of related applications

[0001] This application claims priority to the Chinese patent application filed with the Chinese National Intellectual Property Office on June 22, 2022, with application number 202210708417.8, titled "Corrosion-resistant alloy reinforcing steel and method for manufacturing the same," the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] This application relates to the technical field of reinforcing bars, and more specifically, to corrosion-resistant alloy reinforcing bars and methods for manufacturing the same. [Background technology]

[0003] Reinforced concrete structures are among the most important types of structures, but their lack of durability remains a major challenge for the industry. Corrosion-resistant alloy reinforcing steel combines the appearance, mechanical properties, workability, and corrosion resistance of conventional reinforcing steel, making it an important solution to the durability issues of reinforced concrete structures. However, existing corrosion-resistant alloy reinforcing steel still has several challenges, making it difficult to fully promote its adoption.

[0004] For example, Patent CN112375995A discloses a 400 MPa grade corrosion-resistant reinforcing bar and a method for producing the same. The composition of the 400 MPa grade corrosion-resistant reinforcing bar is Cr: 9.5~10.4 mass%, Mo: 1.0~1.2 mass%, Mn: 0.3~0.6 mass%, Ni: 0.01~1 mass%, Cu: 0.01~0.5 mass%, C≦0.014 mass%, N≦0.004 mass%, Nb: 0.01~0.05 mass%, Si: 0.2~0.6 mass%, with the remainder being Fe and unavoidable impurities. The microstructure of the above corrosion-resistant reinforcing bar is bainite and ferrite, and it belongs to the category of extremely low-carbon, high-alloy corrosion-resistant reinforcing bars, possessing excellent mechanical properties and corrosion resistance.

[0005] However, due to the high content of Cr and Mo in the aforementioned corrosion-resistant reinforcing steel alloy elements, its production costs are high, severely limiting the use of corrosion-resistant reinforcing steel. [Overview of the project] [Problems that the invention aims to solve]

[0006] The technical problem that this invention aims to solve is to overcome the shortcomings of the conventional technology, which suffer from high production costs due to the high content of Cr and Mo in corrosion-resistant reinforcing steel alloy elements, and which severely limits the use of corrosion-resistant reinforcing steel. [Means for solving the problem]

[0007] Therefore, this application provides corrosion-resistant alloy reinforcing steel containing C: 0.05~0.25 wt%, Si: 1.05~2 wt%, Mn: 0.3~1.5 wt%, Cr: 0.5~2.5 wt%, Ni: 0.05~1 wt%, O: 0.001~0.005 wt%, S: 0.001~0.0035 wt%, Ti: 0.005~0.1 wt%, Al: 0.005~0.1 wt%, V: 0.005~0.03 wt%, Nb: 0.005~0.03 wt%, with the remainder being Fe and unavoidable impurities. The Si and Mn content satisfies 2 ≤ Si / Mn ≤ 5, the Si and Cr content satisfies 0.75 ≤ Si / Cr ≤ 1.5, and the Ti and Al content satisfies 0.02 wt% ≤ Ti + Al ≤ 0.2 wt%.

[0008] The Si content is optionally 1.2-1.8%. And / or, the Mn is 0.4-1%, And / or, the Cr content is 0.85-2%.

[0009] The Si content is optionally 1.35 to 1.65%. And / or, the Mn is 0.45-0.75%, And / or, the Cr content is 1.35 to 1.75%.

[0010] Selectively, C is between 0.05% and 0.15%.

[0011] Selectively, C is between 0.07% and 0.12%.

[0012] Selectively, the Ti content is 0.01 to 0.075%. And / or, the Al content is 0.01 to 0.075%.

[0013] The present invention also provides a method for manufacturing the aforementioned corrosion-resistant alloy reinforcing steel, comprising the steps of sequential smelting, refining, continuous casting, rolling, and cooling.

[0014] The raw materials for producing the corrosion-resistant alloy reinforcing steel may optionally include ferrosilicon alloy and silicon-manganese alloy, with a mass ratio of (2-5):1 between the ferrosilicon alloy and the silicon-manganese alloy.

[0015] Optionally, in the continuous casting process, the drawing speed is 2.5 to 3.5 m / min. And / or, in the cooling process, the temperature of the reinforcing bars transferred to the cooling bed is 820°C to 1000°C. and / or the rolling process includes heating the continuous casting billet and performing rough rolling and finish rolling.

[0016] Optionally, the heating temperature for the continuously cast billet is 1150 to 1250°C, the rough rolling temperature is 1000 to 1120°C, and the finish rolling temperature is 1000°C or higher. [Effects of the Invention]

[0017] The technical solution of this application has the following advantages.

[0018] 1. In the corrosion-resistant alloy reinforcing steel according to this application, the Si, Mn, Cr, Al, and Ti in the formulation of this application are comprehensively designed, and by compensating for the decrease in corrosion resistance due to the decrease in Cr content with elements such as Si, Ti, Al, and Mn, a corrosion-resistant alloy reinforcing steel with excellent mechanical properties and corrosion resistance can be obtained even when the Cr content is significantly reduced without incorporating the Mo element into the formulation, and the production cost of the corrosion-resistant alloy reinforcing steel is significantly reduced.

[0019] 2. The corrosion-resistant alloy steel bars according to the present application, based on the chemical composition design of the present application, not only realize the excellent corrosion resistance of the corrosion-resistant alloy steel bars, but also the corrosion-resistant alloy steel bars have excellent mechanical properties, low production costs, and are suitable for actual production and processing.

[0020] 3. The corrosion-resistant alloy steel bars according to the present application, on the premise of the chemical composition design scheme of the present application, are combined with the steelmaking technology and the controlled rolling and controlled cooling processes in the manufacturing method, so as to ensure the exertion of the strengthening effect by alloy elements and obtain a ferrite + pearlite multiphase structure. The corrosion resistance and mechanical properties of the corrosion-resistant alloy steel bars are ensured, and at the same time, the difficulty and production cost of production are reduced.

Embodiments for Carrying out the Invention

[0021] The following examples are provided to better understand the present application, and are not limited to the aforementioned best embodiments, nor do they limit the content and protection scope of the present application. Any product identical or similar to the present application obtained by combining the suggestions of the present application or the features of the present application and other prior arts falls within the protection scope of the present application.

[0022] When specific experimental procedures or conditions are not specified in the examples, they may be carried out according to the operations or conditions of the usual experimental procedures described in the literature in the relevant field. The reagents or instruments used are not specified by the manufacturer, and are all ordinary reagent products that can be obtained through commercial channels.

[0023] The ferrosilicon alloy in the present application has a particle size of 10 - 30 mm, and the main components are Si: 75 wt%, S: 0.002 wt%, C: 0.01 wt%, Al: 0.1 wt%, Ti: 0.01 wt%, P: 0.02 wt%, and the rest are iron and impurities. It was purchased from Qinghai Baitong High-Purity Materials Co., Ltd.

[0024] The silicon-manganese alloy used in this application has a particle size of 10-30 mm, and its main components are Mn: 83 wt%, Si: 1.94 wt%, C: 0.65 wt%, P: 0.15 wt%, S: 0.005 wt%, with the remainder being iron and impurities. It was purchased from Ningxia Yitong Industrial Co., Ltd.

[0025] The ferrochrome alloy used in this application has a particle size of 30-50 mm, and its main components are Cr: 60 wt%, Si: 0.87 wt%, C: 0.14 wt%, S: 0.002 wt%, P: 0.034 wt%, with the remainder being iron and impurities. It was purchased from Tianjin Haoyuan Metal Materials Co., Ltd.

[0026] The ferrotitanium alloy used in this application has a particle size of 10-30 mm, and its main components are Si: 1.85 wt%, S: 0.014 wt%, C: 0.04 wt%, Al: 1.35 wt%, Ti: 32.94 wt%, P: 0.042 wt%, Mn: 1.57 wt%, with the remainder being iron and impurities. It was purchased from Jinzhou Haixin Metal Materials Co., Ltd.

[0027] The ferroniob alloy used in this application has a particle size of 5 to 30 mm, and its main components are Nb: 65.92 wt%, Si: 1.97 wt%, C: 0.12 wt%, Al: 0.94 wt%, S: 0.018 wt%, and P: 0.258 wt%, with the remainder being iron and impurities. It was purchased from Beijing Gaoke New Materials Technology Co., Ltd.

[0028] The vanadium nitrogen alloy used in this application has a particle size of 5-10 mm, and its main components are V: 77.69 wt%, S: 0.075 wt%, C: 5.53 wt%, N: 14.1 wt%, P: 0.045 wt%, with the remainder being iron and impurities. It was purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd.

[0029] In this application, the nickel is 99.9% by weight, with the remainder being iron and impurity elements, and is added as nickel plate purchased from Jiangsu Guoyan Steel Co., Ltd.

[0030] In this application, the aluminum has an aluminum content of 99.5% by weight, with the remainder being iron and impurity elements, and is added as aluminum particles purchased from Xuchang Shengtong Metal Materials Co., Ltd. Example 1

[0031] This invention relates to a material containing C:0.07 wt%, Si:1.35 wt%, Mn:0.45 wt%, Cr:1.35 wt%, Ni:0.05 wt%, O:0.001 wt%, S:0.001 wt%, Ti:0.01 wt%, Al:0.01 wt%, V:0.005 wt%, Nb:0.005 wt%, with the remainder being Fe and unavoidable impurities. Here, we provide a corrosion-resistant alloy reinforcing bar in which the Si and Mn content satisfies Si / Mn=3, the Si and Cr content satisfies Si / Cr=1, and the Ti and Al content satisfies Ti+Al=0.02%. The above method for manufacturing corrosion-resistant alloy reinforcing steel includes the following steps. Smelting process: Ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1610°C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy was 3.3:1, and the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy was 3.3:0.05:0.1:0.05:1. The amount of nickel plate added was 60 kg, the amount of aluminum particles added was 25 kg, and the amount of silicon manganese alloy added was 750 kg. Refining process: Argon gas was introduced into the molten steel, followed by refining at 1550°C for 40 minutes. Continuous casting process: The molten steel after refining was cast into billets using a continuous casting machine, and the drawing speed was set to 3 m / min during continuous casting. The resulting continuous casting billets had a cross-sectional size of 140 mm. 2 That is the case. Rolling process: The continuously cast billet obtained in the continuous casting process was heated to 1190°C over 100 minutes, and then rolled at a rough rolling temperature of 1035°C and a finish rolling temperature of 1000°C to obtain reinforcing bars with a diameter of 14 mm. Cooling process: After cooling the reinforcing bars obtained in the rolling process to 920°C, they were transferred to a cooling bed for further cooling, followed by air cooling, with the conveying speed of the cooling bed set to 2 m / min. Example 2

[0032] This application describes a material containing C: 0.1 wt%, Si: 1.5 wt%, Mn: 0.55 wt%, Cr: 1.5 wt%, Ni: 0.5 wt%, O: 0.003 wt%, S: 0.0025 wt%, Ti: 0.05 wt%, Al: 0.05 wt%, V: 0.015 wt%, Nb: 0.015 wt%, with the remainder being Fe and unavoidable impurities. Here, we provide a corrosion-resistant alloy reinforcing bar that satisfies the following conditions: Si / Mn = 2.7 for Si and Mn content, Si / Cr = 1 for Si and Cr content, and Ti + Al = 0.1% for Ti and Al content. The above method for manufacturing corrosion-resistant alloy reinforcing steel includes the following steps. Smelting process: Ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1630°C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy was 3.1:1, and the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy was 3.1:0.15:0.5:0.15:1. The amount of nickel plate added was 600 kg, the amount of aluminum particles added was 130 kg, and the amount of silicon manganese alloy added was 920 kg. Refining process: Argon gas was introduced into the molten steel, followed by refining at 1555°C for 40 minutes. Continuous casting process: The molten steel after refining was cast into billets using a continuous casting machine, and the drawing speed was set to 2.7 m / min during continuous casting. The resulting continuous casting billet had a cross-sectional size of 140 mm. 2 That is the case. Rolling process: The continuously cast billet obtained in the continuous casting process was heated to 1210°C over 110 minutes, and then rolled at a rough rolling temperature of 1025°C and a finish rolling temperature of 1010°C to obtain reinforcing bars with a diameter of 25 mm. Cooling process: After cooling the reinforcing bars obtained in the rolling process to 930°C, they were transferred to a cooling bed for further cooling, followed by air cooling, with the conveying speed of the cooling bed set to 1.5 m / min. Example 3

[0033] This application describes a material containing C: 0.12 wt%, Si: 1.65 wt%, Mn: 0.75 wt%, Cr: 1.75 wt%, Ni: 1 wt%, O: 0.005 wt%, S: 0.0035 wt%, Ti: 0.075 wt%, Al: 0.075 wt%, V: 0.03 wt%, Nb: 0.03 wt%, with the remainder being Fe and unavoidable impurities. Here, we provide a corrosion-resistant alloy reinforcing bar that satisfies the following conditions: Si / Mn = 2.2 for Si and Mn content, Si / Cr = 0.94 for Si and Cr content, and Ti + Al = 0.15% for Ti and Al content. The above method for manufacturing corrosion-resistant alloy reinforcing steel includes the following steps. Smelting process: Ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1635°C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy was 2.5:1, and the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy was 2.7:0.3:0.8:0.3:1. The amount of nickel plate added was 1200 kg, the amount of aluminum particles added was 250 kg, and the amount of silicon manganese alloy added was 1250 kg. Refining process: Argon gas was introduced into the molten steel, followed by refining at 1515°C for 50 minutes. Continuous casting process: The molten steel after refining was cast into billets using a continuous casting machine, and the drawing speed was set to 2.6 m / min during continuous casting. The resulting continuous casting billet had a cross-sectional size of 140 mm. 2 That is the case. Rolling process: The continuously cast billet obtained in the continuous casting process was heated to 1210°C over 110 minutes, and then rolled at a rough rolling temperature of 1025°C and a finish rolling temperature of 1010°C to obtain reinforcing bars with a diameter of 32 mm. Cooling process: After cooling the reinforcing bars obtained in the rolling process to 880°C, they were transferred to a cooling bed for further cooling, followed by air cooling, with the conveying speed of the cooling bed set to 1.1 m / min. Example 4

[0034] This invention relates to a material containing C: 0.05 wt%, Si: 1.2 wt%, Mn: 0.4 wt%, Cr: 0.85 wt%, Ni: 0.05 wt%, O: 0.001 wt%, S: 0.001 wt%, Ti: 0.005 wt%, Al: 0.025 wt%, V: 0.005 wt%, Nb: 0.005 wt%, with the remainder being Fe and unavoidable impurities. Here, we provide a corrosion-resistant alloy reinforcing bar that satisfies the following conditions: Si / Mn = 3 for Si and Mn content, Si / Cr = 1.41 for Si and Cr content, and Ti + Al = 0.03% for Ti and Al content. The above method for manufacturing corrosion-resistant alloy reinforcing steel includes the following steps. Smelting process: Ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1600°C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy was 3.5:1, and the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy was 2.5:0.05:0.05:0.05:1. The amount of nickel plate added was 60 kg, the amount of aluminum particles added was 70 kg, and the amount of silicon manganese alloy added was 670 kg. Refining process: Argon gas was introduced into the molten steel, followed by refining at 1540°C for 30 minutes. Continuous casting process: The molten steel after refining was cast into billets using a continuous casting machine, and the drawing speed was set to 3 m / min during continuous casting. The resulting continuous casting billets had a cross-sectional size of 140 mm. 2 That is the case. Rolling process: The continuously cast billet obtained in the continuous casting process was heated to 1230°C over 120 minutes, and then rolled at a rough rolling temperature of 1070°C and a finish rolling temperature of 1050°C to obtain reinforcing bars with a diameter of 28 mm. Cooling process: After cooling the reinforcing bars obtained in the rolling process to 920°C, they were transferred to a cooling bed for further cooling, followed by air cooling, with the conveying speed of the cooling bed set to 1.2 m / min. Example 5

[0035] This application describes a material containing C: 0.15 wt%, Si: 1.8 wt%, Mn: 0.9 wt%, Cr: 2 wt%, Ni: 1 wt%, O: 0.005 wt%, S: 0.0035 wt%, Ti: 0.1 wt%, Al: 0.1 wt%, V: 0.03 wt%, Nb: 0.03 wt%, with the remainder being Fe and unavoidable impurities. Here, we provide a corrosion-resistant alloy reinforcing bar that satisfies the following conditions: Si / Mn = 2 for Si and Mn content, Si / Cr = 0.9 for Si and Cr content, and Ti + Al = 0.2% for Ti and Al content. The above method for manufacturing corrosion-resistant alloy reinforcing steel includes the following steps. Smelting process: Ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1639°C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy was 2:1, and the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy was 2.5:0.3:1.2:0.3:1. The amount of nickel plate added was 1200 kg, the amount of aluminum particles added was 30 kg, and the amount of silicon manganese alloy added was 1500 kg. Refining process: Argon gas was introduced into the molten steel, followed by refining at 1560°C for 45 minutes. Continuous casting process: The molten steel after refining was cast into a continuous casting billet using a continuous casting machine. During continuous casting, the drawing speed was set to 2.5 m / min. The resulting continuous casting billet had a cross-sectional size of 140 mm. 2 That is the case. Rolling process: The continuously cast billet obtained in the continuous casting process was heated to 1150°C over 90 minutes, and then rolled at a rough rolling temperature of 1000°C and a finish rolling temperature of 1000°C to obtain reinforcing bars with a diameter of 10 mm. Cooling process: After cooling the reinforcing bars obtained in the rolling process to 820°C, they were transferred to a cooling bed for further cooling, followed by air cooling, with the conveying speed of the cooling bed set to 2.2 m / min. Example 6

[0036] This invention relates to a material containing C: 0.05 wt%, Si: 1.05 wt%, Mn: 0.3 wt%, Cr: 0.8 wt%, Ni: 0.05 wt%, O: 0.001 wt%, S: 0.001 wt%, Ti: 0.025 wt%, Al: 0.005 wt%, V: 0.005 wt%, Nb: 0.005 wt%, with the remainder being Fe and unavoidable impurities. Here, we provide a corrosion-resistant alloy reinforcing bar that satisfies the following conditions: Si / Mn = 3.5 for Si and Mn content, Si / Cr = 1.31 for Si and Cr content, and Ti + Al = 0.03% for Ti and Al content. The above method for manufacturing corrosion-resistant alloy reinforcing steel includes the following steps. Smelting process: Ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1650°C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy was 3.8:1, and the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy was 2.6:0.05:0.3:0.05:1. The amount of nickel plate added was 60 kg, the amount of aluminum particles added was 20 kg, and the amount of silicon manganese alloy added was 500 kg. Refining process: Argon gas was introduced into the molten steel, followed by refining at 1550°C for 35 minutes. Continuous casting process: The molten steel after refining was cast into a continuous casting billet using a continuous casting machine. During continuous casting, the drawing speed was set to 2.5 m / min. The resulting continuous casting billet had a cross-sectional size of 140 mm. 2 That is the case. Rolling process: The continuously cast billet obtained in the continuous casting process was heated to 1180°C over 100 minutes, and then rolled at a rough rolling temperature of 1020°C and a finish rolling temperature of 1000°C to obtain reinforcing bars with a diameter of 18 mm. Cooling process: After cooling the reinforcing bars obtained in the rolling process to 860°C, they were transferred to a cooling bed for further cooling, followed by air cooling, with the conveying speed of the cooling bed set to 1.4 m / min. Example 7

[0037] This application describes a material containing C:0.25 wt%, Si:2 wt%, Mn:1 wt%, Cr:2.5 wt%, Ni:1 wt%, O:0.005 wt%, S:0.0035 wt%, Ti:0.1 wt%, Al:0.1 wt%, V:0.03 wt%, Nb:0.03 wt%, with the remainder being Fe and unavoidable impurities. Here, we provide a corrosion-resistant alloy reinforcing bar in which the Si and Mn content satisfies Si / Mn=2, the Si and Cr content satisfies Si / Cr=0.8, and the Ti and Al content satisfies Ti+Al=0.2%. The above method for manufacturing corrosion-resistant alloy reinforcing steel includes the following steps. Smelting process: Ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1600°C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy was 2.2:1, and the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy was 3:0.3:1.1:0.3:1. The amount of nickel plate added was 1200 kg, the amount of aluminum particles added was 250 kg, and the amount of silicon manganese alloy added was 1665 kg. Refining process: Argon gas was introduced into the molten steel, followed by refining at 1540°C for 40 minutes. Continuous casting process: The molten steel after refining was cast into billets using a continuous casting machine, and the drawing speed was set to 2.7 m / min during continuous casting. The resulting continuous casting billet had a cross-sectional size of 140 mm. 2 That is the case. Rolling process: The continuously cast billet obtained in the continuous casting process was heated to 1250°C over 120 minutes, and then rolled at a rough rolling temperature of 1120°C and a finish rolling temperature of 1100°C to obtain reinforcing bars with a diameter of 22 mm. Cooling process: After cooling the reinforcing bars obtained in the rolling process to 1000°C, they were transferred to a cooling bed for further cooling, followed by air cooling, with the conveying speed of the cooling bed set to 1.45 m / min. Example 8

[0038] This invention relates to a material containing C: 0.1 wt%, Si: 1.05 wt%, Mn: 0.35 wt%, Cr: 0.75 wt%, Ni: 0.15 wt%, O: 0.0025 wt%, S: 0.0025 wt%, Ti: 0.03 wt%, Al: 0.03 wt%, V: 0.01 wt%, Nb: 0.01 wt%, with the remainder being Fe and unavoidable impurities. Here, we provide a corrosion-resistant alloy reinforcing bar that satisfies the following conditions: Si / Mn = 3 for Si and Mn content, Si / Cr = 1.4 for Si and Cr content, and Ti + Al = 0.06% for Ti and Al content. The above method for manufacturing corrosion-resistant alloy reinforcing steel includes the following steps. Smelting process: Ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1620°C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy was 3.3:1, and the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy was 2.1:0.1:0.3:0.1:1. The amount of nickel plate added was 180 kg, the amount of aluminum particles added was 250 kg, and the amount of silicon manganese alloy added was 585 kg. Refining process: Argon gas was introduced into the molten steel, followed by refining at 1545°C for 40 minutes. Continuous casting process: The molten steel after refining was cast into billets using a continuous casting machine, and the drawing speed was set to 3.5 m / min during continuous casting. The resulting continuous casting billet had a cross-sectional size of 140 mm. 2 That is the case. Rolling process: The continuously cast billet obtained in the continuous casting process was heated to 1200°C over 100 minutes, and then rolled at a rough rolling temperature of 1020°C and a finish rolling temperature of 1000°C to obtain reinforcing bars with a diameter of 16 mm. Cooling process: After cooling the steel bars obtained in the rolling process to 880 °C, they were transferred to a cooling bed for cooling, air-cooled, and the conveying speed of the cooling bed was set to 1.6 m / min. Example 9

[0039] This application contains C: 0.25 wt%, Si: 1.5 wt%, Mn: 0.3 wt%, Cr: 1 wt%, Ni: 0.05 wt%, O: 0.001 wt%, S: 0.001 wt%, Ti: 0.1 wt%, Al: 0.05 wt%, V: 0.005 wt%, Nb: 0.005 wt%, and the balance is Fe and inevitable impurities. Here, the contents of Si and Mn satisfy Si / Mn = 5, the contents of Si and Cr satisfy Si / Cr = 1.5, and the contents of Ti and Al satisfy Ti + Al = 0.15%, to provide a corrosion-resistant alloy steel bar. The manufacturing method of the above corrosion-resistant alloy steel bar includes the following steps. Smelting process: Ferrochrome alloy, ferroniobium alloy, ferro titanium alloy, vanadium nitride alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1650 °C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy is 5:1, the mass ratio of ferrochrome alloy, ferroniobium alloy, ferro titanium alloy, vanadium nitride alloy, and silicon manganese alloy is 3.3:0.05:1.1:0.05:1, the addition amount of nickel plate is 60 kg, the addition amount of aluminum particles is 125 kg, and the addition amount of silicon manganese alloy is 500 kg. Refining process: Argon gas was introduced into the molten steel, and then refined at 1560 °C for 60 min. Continuous casting process: The molten steel after refining was made into continuous casting billets by a continuous caster. When continuous casting, the drawing speed was set to 3.1 m / min. The cross-sectional size of the obtained continuous casting billet is 140 mm 2 is. Rolling process: The continuous casting billets obtained in the continuous casting process were heated to 1230 °C over 120 min, and then rolled with the rough rolling temperature set to 1060 °C and the finish rolling temperature set to 1000 °C to obtain steel bars with a diameter of 22 mm. Cooling process: After cooling the reinforcing bars obtained in the rolling process to 1000°C, they were transferred to a cooling bed for further cooling, followed by air cooling, with the conveying speed of the cooling bed set to 1.45 m / min. Example 10

[0040] This application describes a material containing C: 0.05 wt%, Si: 1.86 wt%, Mn: 0.93 wt%, Cr: 2.48 wt%, Ni: 1 wt%, O: 0.005 wt%, S: 0.0035 wt%, Ti: 0.005 wt%, Al: 0.015 wt%, V: 0.03 wt%, Nb: 0.03 wt%, with the remainder being Fe and unavoidable impurities. Here, we provide a corrosion-resistant alloy reinforcing bar that satisfies the following conditions: Si / Mn = 2 for Si and Mn content, Si / Cr = 0.75 for Si and Cr content, and Ti + Al = 0.02% for Ti and Al content. The above method for manufacturing corrosion-resistant alloy reinforcing steel includes the following steps. Smelting process: Ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, ferrosilicon alloy, silicon manganese alloy, nickel plate, and aluminum particles were smelted at 1600°C to obtain molten steel. The mass ratio of ferrosilicon alloy to silicon manganese alloy was 2.2:1, and the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy was 3.0:0.3:0.2:0.3:1. The amount of nickel plate added was 1200 kg, the amount of aluminum particles added was 325 kg, and the amount of silicon manganese alloy added was 1550 kg. Refining process: Argon gas was introduced into the molten steel, followed by refining at 1540°C for 30 minutes. Continuous casting process: The molten steel after refining was cast into billets using a continuous casting machine, and the drawing speed was set to 2.8 m / min during continuous casting. The resulting continuous casting billet had a cross-sectional size of 140 mm. 2 That is the case. Rolling process: The continuously cast billet obtained in the continuous casting process was heated to 1180°C over 90 minutes, and then rolled at a rough rolling temperature of 1020°C and a finish rolling temperature of 1000°C to obtain reinforcing bars with a diameter of 22 mm. Cooling process: After cooling the reinforcing bars obtained in the rolling process to 950°C, they were transferred to a cooling bed for further cooling, followed by air cooling, with the conveying speed of the cooling bed set to 1.45 m / min. Comparative Example 1

[0041] This application relates to a material containing C: 0.1 wt%, Si: 2.15 wt%, Mn: 0.3 wt%, Cr: 1 wt%, Ni: 0.05 wt%, O: 0.001 wt%, S: 0.0035 wt%, Ti: 0.08 wt%, Al: 0.07 wt%, V: 0.005 wt%, and Nb: 0.005 wt. The present invention provides corrosion-resistant alloy reinforcing steel in which the Si and Mn content satisfies Si / Mn = 7.17, the Si and Cr content satisfies Si / Cr = 2.15, and the Ti and Al content satisfies Ti + Al = 0.15%. The above method for manufacturing corrosion-resistant alloy reinforcing bars differs from Example 8 only in that, in the smelting step, the mass ratio of ferrosilicon alloy to silicon manganese alloy is 6.5:1, the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy is 3.6:0.05:0.8:0.05:1, the amount of nickel plate added is 60 kg, the amount of aluminum particles added is 180 kg, and the amount of silicon manganese alloy added is 500 kg. Comparative Example 2

[0042] This application relates to a material containing C: 0.1 wt%, Si: 1.5 wt%, Mn: 1.65 wt%, Cr: 1 wt%, Ni: 0.05 wt%, O: 0.001 wt%, S: 0.0035 wt%, Ti: 0.08 wt%, Al: 0.07 wt%, V: 0.005 wt%, and Nb: 0.005 wt. The present invention provides corrosion-resistant alloy reinforcing steel in which the Si and Mn content satisfies Si / Mn = 0.91, the Si and Cr content satisfies Si / Cr = 1.5, and the Ti and Al content satisfies Ti + Al = 0.15%. The above method for manufacturing corrosion-resistant alloy reinforcing bars differs from Example 8 only in that, in the smelting step, the mass ratio of ferrosilicon alloy to silicon manganese alloy is 0.8:1, the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy is 0.6:0.05:0.8:0.05:1, the amount of nickel plate added is 60 kg, the amount of aluminum particles added is 180 kg, and the amount of silicon manganese alloy added is 2750 kg. Comparative Example 3

[0043] This application relates to a material containing C: 0.1 wt%, Si: 1.5 wt%, Mn: 0.3 wt%, Cr: 3 wt%, Ni: 0.05 wt%, O: 0.001 wt%, S: 0.0035 wt%, Ti: 0.08 wt%, Al: 0.07 wt%, V: 0.005 wt%, and Nb: 0.005 wt. The present invention provides corrosion-resistant alloy reinforcing steel in which the Si and Mn content satisfies Si / Mn=5, the Si and Cr content satisfies Si / Cr=0.5, and the Ti and Al content satisfies Ti+Al=0.15%. The above method for manufacturing corrosion-resistant alloy reinforcing bars differs from Example 8 only in that, in the smelting step, the mass ratio of ferrosilicon alloy to silicon manganese alloy is 4.5:1, the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy is 10:0.05:0.8:0.05:1, the amount of nickel plate added is 60 kg, the amount of aluminum particles added is 180 kg, and the amount of silicon manganese alloy added is 500 kg. Comparative Example 4

[0044] This application relates to a material containing C: 0.1 wt%, Si: 1.5 wt%, Mn: 0.3 wt%, Cr: 1 wt%, Ni: 0.05 wt%, O: 0.001 wt%, S: 0.0035 wt%, Ti: 0.15 wt%, Al: 0.07 wt%, V: 0.005 wt%, and Nb: 0.005 wt. The present invention provides corrosion-resistant alloy reinforcing steel in which the Si and Mn content satisfies Si / Mn=5, the Si and Cr content satisfies Si / Cr=1.5, and the Ti and Al content satisfies Ti+Al=0.22%. The above method for manufacturing corrosion-resistant alloy reinforcing bars differs from Example 8 only in that, in the smelting step, the mass ratio of ferrosilicon alloy to silicon manganese alloy is 4.5:1, the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy is 3.3:0.05:1.55:0.05:1, the amount of nickel plate added is 60 kg, the amount of aluminum particles added is 180 kg, and the amount of silicon manganese alloy added is 500 kg. Comparative Example 5

[0045] This application relates to a material containing C: 0.1 wt%, Si: 1.5 wt%, Mn: 0.3 wt%, Cr: 1 wt%, Ni: 0.05 wt%, O: 0.001 wt%, S: 0.0035 wt%, Ti: 0.08 wt%, Al: 0.15 wt%, V: 0.005 wt%, and Nb: 0.005 wt. The present invention provides corrosion-resistant alloy reinforcing steel in which the Si and Mn content satisfies Si / Mn=5, the Si and Cr content satisfies Si / Cr=1.5, and the Ti and Al content satisfies Ti+Al=0.22%. The above method for manufacturing corrosion-resistant alloy reinforcing bars differs from Example 8 only in that, in the smelting step, the mass ratio of ferrosilicon alloy to silicon manganese alloy is 4.5:1, the mass ratio of ferrochrome alloy, ferroniob alloy, ferrotitanium alloy, vanadium nitrogen alloy, and silicon manganese alloy is 3.3:0.05:0.8:0.05:1, the amount of nickel plate added is 60 kg, the amount of aluminum particles added is 380 kg, and the amount of silicon manganese alloy added is 500 kg. Test Example 1

[0046] The mechanical properties of the corrosion-resistant alloy reinforcing bars produced in the examples and comparative examples were tested according to the national standard GB / T228.1-2010 Tensile Testing of Metallic Materials Part 1: Room Temperature Test Methods. The tensile strength-to-yield strength ratio (i.e., tensile strength / yield strength) was calculated, and the test results are shown in Table 1.

[0047] [Table 1] As can be seen from the data in Table 1, in this invention, yield strength ≥ 430 MPa, elongation after break ≥ 20.5%, tensile strength-to-yield strength ratio ≥ 1.26, and maximum total elongation ≥ 10.6% are ensured only when the proportion conditions of each element are met, and excellent mechanical properties can be obtained even when the Cr element content is significantly reduced without adding Mo to the formulation. Test Example 2

[0048] Using a Zeiss optical microscope, the microstructure of the corrosion-resistant alloy reinforcing bars produced in the examples and comparative examples was observed under 200x magnification, and the volume percentage of ferrite was calculated. The test results are shown in Table 2. Test Example 3

[0049] Using an electrochemical workstation equipped with a working electrode, reference electrode, and counter electrode system, the critical chloride ion concentration values ​​at which the passivation film on the surface of corrosion-resistant alloy reinforcing bars manufactured in the examples and comparative examples were tested and compared with HRB400 model reinforcing bars to calculate the improvement factor of the critical chloride ion concentration value. The specific test method is as follows: Test samples were immersed in a saturated sodium hydroxide solution for 48 hours, and then placed in the electrochemical workstation and used as the working electrode. Every 24 hours, 0.01 mol / L of sodium chloride solution was added to the solution in the electrochemical workstation, and the voltage / current-chloride ion concentration curve was tested. When the current or voltage changed rapidly, the corresponding chloride ion concentration value became the critical chloride ion concentration value. The calculation formula is: Improvement factor = Critical chloride ion concentration value of corrosion-resistant alloy reinforcing bar / Critical chloride ion concentration value of HRB400 reinforcing bar. The test results are shown in Table 2. The composition and mixing ratio of the reinforcing steel in the above HRB400 model are as follows: C: 0.24%, Si: 0.40%, Mn: 1.40%, V: 0.025%, P ≤ 0.04%, S ≤ 0.04%. Test Example 4

[0050] The chlorine corrosion resistance of the corrosion-resistant alloy reinforcing bars produced in the examples and comparative examples was tested, and the improvement factor in chlorine corrosion resistance was calculated by comparing them with the HRB400 model reinforcing bars. The specific test method is as follows: One end of each example and comparative example corrosion-resistant alloy reinforcing bar was cut to a length of 100 mm, and a test piece with a diameter of 8 mm was manufactured by turning using a lathe. This test piece was placed in a corrosion solution at a temperature of 35°C and a humidity of 80% and subjected to a salt spray corrosion test. The corrosion solution used for the test was a sodium chloride solution with a chloride salt concentration of 5 wt%, a pH of 7.0, and a test period of 14 days. The weight of the test samples before and after corrosion was tested using an electronic microbalance. The calculation formula is: Improvement factor = Weight change of corrosion-resistant alloy reinforcing bar before and after corrosion / Weight change of HRB400 before and after corrosion. The test results are shown in Table 2. The composition and mixing ratio of the reinforcing steel in the above HRB400 model are as follows: C: 0.24%, Si: 0.40%, Mn: 1.40%, V: 0.025%, P ≤ 0.04%, S ≤ 0.04%.

[0051] [Table 2] JPEG0007846242000003.jpg116138

[0052] From the results in Table 2 above, it was found that in the corrosion-resistant alloy reinforcing steel according to the present invention, the proportion of ferrite in the microstructure type reaches 53-73%, the critical chloride ion concentration is improved by more than 2.1 times, the resistance to chlorine corrosion is improved by more than 2.7 times, and the overall performance is significantly improved compared to HRB400.

[0053] From the data in Tables 1 and 2, it was found that the composition ratio of the present invention achieves a balance between mechanical properties and corrosion resistance, resulting in superior overall performance. Furthermore, the composition formulation of the present invention does not contain the element Mo, and the content of the element Cr is significantly reduced, leading to a substantial reduction in cost.

[0054] Clearly, the above embodiments are merely illustrative examples and do not limit the embodiments. Those skilled in the art may make other different forms of variations or modifications based on the above description. It is neither necessary nor possible to cover all embodiments comprehensively here. And any obvious variations or modifications derived therefrom still fall within the scope of the present invention.

Claims

1. It contains C: 0.05-0.25 wt%, Si: 1.05-2 wt%, Mn: 0.3-1.5 wt%, Cr: 0.5-2.5 wt%, Ni: 0.05-1 wt%, O: 0.001-0.005 wt%, S: 0.001-0.0035 wt%, Ti: 0.005-0.1 wt%, Al: 0.005-0.1 wt%, V: 0.005-0.03 wt%, Nb: 0.005-0.03 wt%, with the remainder being Fe and unavoidable impurities. The content of Si and Mn satisfies 2 ≤ Si / Mn ≤ 5, the content of Si and Cr satisfies 0.75 ≤ Si / Cr ≤ 1.5, and the content of Ti and Al satisfies 0.02% ≤ Ti + Al ≤ 0.2%. This corrosion-resistant alloy reinforcing steel is characterized by a ferrite + pearlite multiphase microstructure, with ferrite accounting for 53-73% of the total microstructure by volume.

2. The Si content is 1.2 to 1.8%, and / or, the Mn content is 0.4 to 1%, The corrosion-resistant alloy reinforcing steel according to claim 1, characterized in that the Cr content is 0.85 to 2%.

3. The Si content is 1.35 to 1.65%, And / or, the Mn content is 0.45 to 0.75%, The corrosion-resistant alloy reinforcing steel according to claim 2, characterized in that the Cr content is 1.35 to 1.75%.

4. The corrosion-resistant alloy reinforcing steel according to claim 1, characterized in that the content of C is 0.05 to 0.15%.

5. The corrosion-resistant alloy reinforcing steel according to claim 4, characterized in that the content of C is 0.07 to 0.12%.

6. The Ti content is 0.01 to 0.075%, The corrosion-resistant alloy reinforcing steel according to claim 1, characterized in that the Al content is 0.01 to 0.075%.

7. A method for producing corrosion-resistant alloy reinforcing steel according to any one of claims 1 to 6, characterized in that it includes the steps of smelting, refining, continuous casting, rolling, and cooling, which are carried out sequentially.

8. The manufacturing method according to claim 7, characterized in that the raw materials for producing the corrosion-resistant alloy reinforcing steel include a ferrosilicon alloy and a silicon-manganese alloy, and the mass ratio of the ferrosilicon alloy to the silicon-manganese alloy is (2 to 5):

1.

9. In the aforementioned continuous casting process, the drawing speed is 2.5 to 3.5 m / min. And / or, in the cooling step, the temperature of the reinforcing bars transferred to the cooling bed is 820°C to 1000°C. The manufacturing method according to claim 7, characterized in that the rolling step includes heating the continuous casting billet and performing rough rolling and finish rolling.

10. The manufacturing method according to claim 9, characterized in that the temperature at which the continuously cast billet is heated is 1150 to 1250°C, the rough rolling temperature is 1000 to 1120°C, and the finish rolling temperature is 1000°C or higher.

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