A low-cost production method of Ti-alloyed X42M pipeline steel plate for export

Abstract

The application discloses a production method of a low-cost Ti-alloyed X42M pipeline steel plate for export, which comprises the following steps: (1) a converter process; (2) an LF refining process; (3) a continuous casting process; (4) a heating process; (5) a rolling mill process; (6) a straightening process; and (7) a flaw detection process. The chemical components of the X42M pipeline steel plate are as follows: C: 0.05-0.08%, Si: 0.10-0.30%, Mn: 1.30-1.50%, P: ≤0.015%, S: ≤0.005%, Ti: 0.015-0.030%, Al: 0.020-0.050%, and the balance of Fe and inevitable impurities. The Ti micro-alloying can refine grains, and the production cost can be greatly reduced while the product performance is ensured.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgy technology, and in particular relates to a low-cost method for producing Ti alloyed X42M pipeline steel plates for export. Background Technology

[0002] Patent CN 110735084 A discloses a hot-rolled X42M pipeline steel strip and its preparation method, and patent CN112111689 A discloses a hot-rolled X42M pipeline steel strip with Nb+Mo composition for export and its preparation process. Both inventions use Nb and Mo alloying, which greatly increases the production cost. Summary of the Invention

[0003] The purpose of this invention is to provide a low-cost method for producing Ti alloyed X42M pipeline steel plates for export. By refining the grains through Ti microalloying, the product meets the requirements of API Spec 5L 46th standard, significantly reducing production costs while ensuring product performance.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] This invention discloses a low-cost method for producing Ti alloyed X42M pipeline steel plates for export, comprising:

[0006] (1) Converter process: oxygen blowing and decarburization in converter, slag formation and dephosphorization, steel tapping temperature in converter ≥1620℃, aluminum ferro, silicon ferro and manganese ferro added during steel tapping process for deoxidation and alloying.

[0007] (2) LF refining process: LF refining involves slag formation and desulfurization, and the addition of aluminum ferrophosphate, silicon ferrophosphate, manganese ferrophosphate, and titanium ferrophosphate alloys. After the LF treatment, calcium treatment is carried out, and the soft blowing time after calcium treatment is guaranteed to be more than 8 minutes;

[0008] (3) Continuous casting process: The casting machine adopts constant casting speed control, and the casting speed is controlled at 1.0 to 1.5 m / min;

[0009] (4) Heating process: Heating temperature ≥1180℃, furnace time ≥180 minutes;

[0010] (5) Rolling mill process: The rolling process consists of two processes: roughing and finishing. The roughing start temperature is ≥1150℃ and the roughing finish temperature is ≥1100℃. The finishing start temperature is ≤1000℃ and the finishing finish temperature is 830-860℃. After rolling, ACC cooling is used, and the cooling temperature is 500-560℃.

[0011] (6) Straightening process: Straightening temperature ≥500℃, steel plate straightness ≤12mm / m;

[0012] The chemical composition of the X42M pipeline steel plate, by weight percentage, is C: 0.05-0.08%, Si: 0.10-0.30%, Mn: 1.30-1.50%, P: ≤0.015%, S: ≤0.005%, Ti: 0.015-0.030%, Al: 0.020-0.050%, with the balance being Fe and unavoidable impurities.

[0013] Furthermore, it also includes: (7) Flaw detection process: Flaw detection is carried out in accordance with the provisions of EN10160 standard, the layer inspection coverage is 100% of the steel plate surface, and there are no layer defects within 50mm of the longitudinal edge of the steel plate.

[0014] Furthermore, the chemical composition of the X42M pipeline steel plate by weight percentage is C: 0.060%, Si: 0.20%, Mn: 1.35%, P: 0.013%, S: 0.005%, Ti: 0.020%, Al: 0.035%, with the balance being Fe and unavoidable impurities.

[0015] Furthermore, the chemical composition of the X42M pipeline steel plate by weight percentage is C: 0.065%, Si: 0.115%, Mn: 1.40%, P: 0.013%, S: 0.004%, Ti: 0.020%, Al: 0.040%, with the balance being Fe and unavoidable impurities.

[0016] Furthermore, the produced X42M pipeline steel plate has an elongation of ≥25%.

[0017] Furthermore, the produced X42M pipeline steel plates exhibit excellent strength and low-temperature toughness.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0019] The X42M pipeline steel plate of this invention refines the grains through Ti microalloying, which significantly reduces production costs while ensuring product performance. Compared with Nb and Mo composition design, the cost per ton of steel is reduced by more than 400 yuan. In the context of steel products no longer enjoying export tax rebates, this greatly improves the product's profitability and competitiveness in foreign markets. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 This is the organization of Embodiment 1 of the present invention. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are merely descriptions of the best mode of implementation of the present invention and do not limit the scope of the present invention in any way.

[0023] Examples 1-2 illustrate the chemical composition and process parameters used in the X42M pipeline steel plate of this invention. The chemical compositions of each example and comparative example are shown in Table 1; the process parameters are shown in Table 2; and the mechanical properties are shown in Table 3.

[0024] Table 1. Chemical composition (%) of each example and comparative example.

[0025]

[0026]

[0027] Table 2 Process Parameters

[0028]

[0029] Table 3 Mechanical Properties

[0030]

[0031]

[0032] As can be seen from the table above, the performance of the embodiments and the comparative examples is basically the same. However, compared with the comparative examples, the alloy cost of the embodiments is significantly reduced, which greatly improves the profitability of the products and their competitiveness in foreign markets.

[0033] 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 low-cost method for producing Ti alloyed X42M pipeline steel plates for export, characterized in that: include: (1) Converter process: oxygen blowing and decarburization in the converter, slag formation and dephosphorization, the steel tapping temperature of the converter is ≥1620℃, and aluminum ferrosilicon and ferromanganese are added during the steel tapping process for deoxidation and alloying. (2) LF refining process: LF refining slag formation and desulfurization, and adding aluminum ferrosilicon ferromanganese and titanium ferroalloys; after the LF treatment is completed, calcium treatment is carried out, and the soft blowing time is guaranteed to be more than 8 minutes after the calcium treatment; (3) Continuous casting process: The casting machine adopts constant casting speed control, and the casting speed is controlled at 1.0~1.5m / min; (4) Heating process: heating temperature ≥1180℃, furnace time ≥180 minutes; (5) Rolling mill process: The rolling process consists of two processes: roughing and finishing. The roughing start temperature is ≥1150℃ and the roughing finish temperature is ≥1100℃. The finishing start temperature is ≤1000℃ and the finishing finish temperature is 830-860℃. After rolling, ACC cooling is used, and the cooling temperature is 500-560℃. (6) Straightening process: Straightening temperature ≥ 500℃, steel plate straightness ≤ 12mm / m; The chemical composition of the X42M pipeline steel plate, by weight percentage, is C: 0.05-0.08%, Si: 0.10-0.30%, Mn: 1.30-1.50%, P: ≤0.015%, S: ≤0.005%, Ti: 0.015-0.030%, Al: 0.020-0.050%, with the balance being Fe and unavoidable impurities; The produced X42M pipeline steel plate has an elongation of ≥25%.

2. The method for producing low-cost Ti alloyed X42M pipeline steel plates for export according to claim 1, characterized in that: Also includes: (7) Flaw detection process: Flaw detection shall be carried out in accordance with the provisions of EN10160 standard. The layer inspection coverage shall be 100% of the steel plate surface, and there shall be no layer defects within 50mm of the longitudinal edge of the steel plate.

3. The method for producing low-cost Ti alloyed X42M pipeline steel plates for export according to claim 1, characterized in that: The chemical composition of the X42M pipeline steel plate, by weight percentage, is C: 0.060%, Si: 0.20%, Mn: 1.35%, P: 0.013%, S: 0.005%, Ti: 0.020%, Al: 0.035%, with the balance being Fe and unavoidable impurities.

4. The method for producing low-cost Ti alloyed X42M pipeline steel plates for export according to claim 1, characterized in that: The chemical composition of the X42M pipeline steel plate, by weight percentage, is C: 0.065%, Si: 0.115%, Mn: 1.40%, P: 0.013%, S: 0.004%, Ti: 0.020%, Al: 0.040%, with the balance being Fe and unavoidable impurities.

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