Corrosion-resistant steel for oil well and production method for corrosion-resistant steel

Abstract

The invention provides corrosion-resistant steel for an oil well and relates to the technical field of steel. The corrosion-resistant steel is prepared from, by mass, 0.10%-0.20% of C, 0.20%-1% of Si, 0.05%-1.5% of Mn, 4.0%-6.0% of Cr, 0.10-1.0% of Ni, 0.10%-0.8% of Mo, 0.20%-0.80% of Cu, 0.01%-0.10% of Al and the balance Fe and inevitable impurity elements, wherein the total content of the inevitable impurity elements is not higher than 0.5%. The corrosion-resistant steel for the oil well achieves the mechanical properties that the yield strength ranges from 1,020 MPa to 1,150 MPa, the tensile strength ranges from 1,140 MPa to 1,300 MPa, the elongation is around 20%, and the Kv of a 140 ksi steel grade casting pipe product is around 30 J at 0 DEG C. In addition, the corrosion-resistant steel for the oil well belongs to the category of low-alloy steel, and the content of Cr and Ni is low; and the CO2 corrosion resisting performance and the H2S corrosion resisting performance of the steel are improved through the methods such as simultaneously adding a small quantity of elements retarding the anode process and elements promoting the cathode process and the surface activity. The corrosion-resistant steel for the oil well is low manufacturing cost and high in CO2 corrosion and H2S stress corrosion resistance.

Description

technical field

[0001] The invention relates to the technical field of iron and steel, in particular to a corrosion-resistant steel for oil wells and a production method thereof. Background technique

[0002] The common corrosion method of steel is chemical corrosion. After the steel reacts with oxidizing gases such as air, oxygen, water vapor, carbon dioxide, sulfur dioxide and chlorine, it will form loose oxides to cause oxidative corrosion, or it will react with sulfides, such as H 2 Contact with substances such as S causes sulfidation corrosion.

[0003] Currently, in anti-CO 2 In the selection of corrosion materials, the addition of Cr, Ni, Mo and other elements that can improve the thermodynamic stability of the alloy and directly block the anodic process is commonly used in the world, so that the surface of the material can quickly form a highly stable alloy group with a thickness of one or several atomic layers. The surface protection layer of the element corrodes ...

Examples

Embodiment 1

[0055] This embodiment provides a kind of corrosion-resistant steel for oil wells, which has the chemical composition as shown in Example 1 in Table 1 in terms of mass percentage:

[0056] Except for the chemical elements in Table 1, the rest are Fe and unavoidable impurity elements, and the total content of unavoidable impurity elements is not more than 0.5%, among unavoidable impurities: S: ≤0.01%, P ≤0.01%, N+O+H ≤80ppm.

[0057] The production method of corrosion-resistant steel for oil well in the present embodiment comprises the following steps:

[0058] S1: the step of electric furnace smelting, adding steel scrap and / or pig iron into the electric furnace for smelting, smelting until the carbon content is lower than 0.3%, and the phosphorus content is lower than 0.01%, and the steel is tapped;

[0059] S2: the step of tapping, adding Si and Mn alloy elements for deoxidation during tapping, and adding carbon powder and slagging agent;

[0060] S3: the step of refining ...

Embodiment 2

[0066] This embodiment provides a corrosion-resistant steel for oil wells, which has the chemical composition as shown in Example 2 in Table 1 in terms of mass percentage:

[0067] Except for the chemical elements in Table 1, the rest are Fe and unavoidable impurity elements, and the total content of unavoidable impurity elements is not more than 0.5%, among unavoidable impurities: S: ≤0.01%, P ≤0.01%, N+O+H ≤80ppm.

[0068] The production method of corrosion-resistant steel for oil wells of the present embodiment comprises the following steps:

[0069] S1: the step of electric furnace smelting, adding steel scrap and / or pig iron into the electric furnace for smelting, smelting until the carbon content is lower than 0.3%, and the phosphorus content is lower than 0.01%, and the steel is tapped;

[0070] S2: the step of tapping, adding Si and Mn alloy elements for deoxidation during tapping, and adding carbon powder and slagging agent;

[0071] S3: the step of refining outside...

Embodiment 3

[0077] This embodiment provides a kind of corrosion-resistant steel for oil wells, which has the chemical composition as shown in Example 3 in Table 1 in terms of mass percentage:

[0078] Except for the chemical elements in Table 1, the rest are Fe and unavoidable impurity elements, and the total content of unavoidable impurity elements is not more than 0.5%, among unavoidable impurities: S: ≤0.01%, P ≤0.01%, N+O+H ≤80ppm.

[0079] The production method of corrosion-resistant steel for oil wells of the present embodiment comprises the following steps:

[0080] S1: the step of electric furnace smelting, adding steel scrap and / or pig iron into the electric furnace for smelting, smelting until the carbon content is lower than 0.3%, and the phosphorus content is lower than 0.01%, and the steel is tapped;

[0081] S2: the step of tapping, adding Si and Mn alloy elements for deoxidation during tapping, and adding carbon powder and slagging agent;

[0082] S3: the step of refining...

technical field

[0001] The invention relates to the technical field of iron and steel, in particular to a corrosion-resistant steel for oil wells and a production method thereof. Background technique

[0002] The common corrosion method of steel is chemical corrosion. After the steel reacts with oxidizing gases such as air, oxygen, water vapor, carbon dioxide, sulfur dioxide and chlorine, it will form loose oxides to cause oxidative corrosion, or it will react with sulfides, such as H 2 Contact with substances such as S causes sulfidation corrosion.

[0003] Currently, in anti-CO 2 In the selection of corrosion materials, the addition of Cr, Ni, Mo and other elements that can improve the thermodynamic stability of the alloy and directly block the anodic process is commonly used in the world, so that the surface of the material can quickly form a highly stable alloy group with a thickness of one or several atomic layers. The surface protection layer of the element corrodes ...

Examples

Embodiment 1

[0055] This embodiment provides a kind of corrosion-resistant steel for oil wells, which has the chemical composition as shown in Example 1 in Table 1 in terms of mass percentage:

[0056] Except for the chemical elements in Table 1, the rest are Fe and unavoidable impurity elements, and the total content of unavoidable impurity elements is not more than 0.5%, among unavoidable impurities: S: ≤0.01%, P ≤0.01%, N+O+H ≤80ppm.

[0057] The production method of corrosion-resistant steel for oil well in the present embodiment comprises the following steps:

[0058] S1: the step of electric furnace smelting, adding steel scrap and / or pig iron into the electric furnace for smelting, smelting until the carbon content is lower than 0.3%, and the phosphorus content is lower than 0.01%, and the steel is tapped;

[0059] S2: the step of tapping, adding Si and Mn alloy elements for deoxidation during tapping, and adding carbon powder and slagging agent;

[0060] S3: the step of refining ...

Embodiment 2

[0066] This embodiment provides a corrosion-resistant steel for oil wells, which has the chemical composition as shown in Example 2 in Table 1 in terms of mass percentage:

[0067] Except for the chemical elements in Table 1, the rest are Fe and unavoidable impurity elements, and the total content of unavoidable impurity elements is not more than 0.5%, among unavoidable impurities: S: ≤0.01%, P ≤0.01%, N+O+H ≤80ppm.

[0068] The production method of corrosion-resistant steel for oil wells of the present embodiment comprises the following steps:

[0069] S1: the step of electric furnace smelting, adding steel scrap and / or pig iron into the electric furnace for smelting, smelting until the carbon content is lower than 0.3%, and the phosphorus content is lower than 0.01%, and the steel is tapped;

[0070] S2: the step of tapping, adding Si and Mn alloy elements for deoxidation during tapping, and adding carbon powder and slagging agent;

[0071] S3: the step of refining outside...

Embodiment 3

[0077] This embodiment provides a kind of corrosion-resistant steel for oil wells, which has the chemical composition as shown in Example 3 in Table 1 in terms of mass percentage:

[0078] Except for the chemical elements in Table 1, the rest are Fe and unavoidable impurity elements, and the total content of unavoidable impurity elements is not more than 0.5%, among unavoidable impurities: S: ≤0.01%, P ≤0.01%, N+O+H ≤80ppm.

[0079] The production method of corrosion-resistant steel for oil wells of the present embodiment comprises the following steps:

[0080] S1: the step of electric furnace smelting, adding steel scrap and / or pig iron into the electric furnace for smelting, smelting until the carbon content is lower than 0.3%, and the phosphorus content is lower than 0.01%, and the steel is tapped;

[0081] S2: the step of tapping, adding Si and Mn alloy elements for deoxidation during tapping, and adding carbon powder and slagging agent;

[0082] S3: the step of refining...

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