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High-cleanliness pipeline steel smelting process

A high-cleanliness, pipeline steel technology, applied in the field of metallurgy, can solve problems such as carburization of molten steel, inability to produce stable batches, insufficient consumption of steel materials for converter furnace condition maintenance, etc.

Active Publication Date: 2015-05-20
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the use of carbon-containing materials such as alloys, covering agents, mold slags, and corrosion of refractory materials during the process from tapping the converter to pouring, it will inevitably cause carburization of the molten steel. Generally, the carbon content of the finished product is between 0.04% and 0.08%, and the anti-HIC pipeline Steel requires finished product C≤0.04%. Only relying on decarburization of the converter and controlling the carbon increase in the subsequent process cannot be produced stably in batches. In addition, there are certain deficiencies in the maintenance of the converter and the consumption of steel materials.

Method used

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  • High-cleanliness pipeline steel smelting process

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Embodiment 1

[0031] This embodiment provides a high-cleanliness pipeline steel smelting process. In this embodiment, X70 pipeline steel is selected, and its main chemical composition is shown in Table 1; figure 1 As shown, the process route is: molten iron pouring → molten iron pretreatment → converter smelting → tapping deoxidation alloying → LF refining furnace → calcium treatment → RH vacuum furnace → continuous casting, which is characterized in that it includes the following specific steps:

[0032] Step 1, converter smelting:

[0033] (1) Hot metal pretreatment operation: the hot metal in the furnace is pretreated by desulfurization and slag is cleaned, wherein the S element content is 0.001%, and the S element content in scrap steel is 0.005%;

[0034] (2) Deep dephosphorization in the converter treatment process: adopt the "double slag method", blow smelting in the converter for 4 minutes, that is, the stage of the carbon-oxygen reaction, and perform the first slag dumping. Using ...

Embodiment 2

[0050] This embodiment provides a high-cleanliness pipeline steel smelting process. In this embodiment, X70 pipeline steel is selected, and its main chemical composition is shown in Table 1; figure 1 As shown, the process route is: molten iron pouring → molten iron pretreatment → converter smelting → tapping deoxidation alloying → LF refining furnace → calcium treatment → RH vacuum furnace → continuous casting, which is characterized in that it includes the following specific steps:

[0051] Step 1, converter smelting:

[0052] (1) Hot metal pretreatment operation: the hot metal that enters the furnace is pretreated by desulfurization and cleaned of slag, wherein the S element content is 0.004%, and the S element content in scrap steel is 0.008%;

[0053] (2) Deep dephosphorization in the converter treatment process: adopt the "double slag method", blowing in the converter for 5 minutes, that is, the stage of the carbon-oxygen reaction, and perform the first slag dumping. Usi...

Embodiment 3

[0069] This embodiment provides a high-cleanliness pipeline steel smelting process. In this embodiment, X70 pipeline steel is selected, such as figure 1 As shown, this embodiment provides a high-cleanliness pipeline steel smelting process. In this embodiment, X70 pipeline steel is selected, and its main chemical composition is shown in Table 1; figure 1 As shown, the process route is: molten iron pouring → molten iron pretreatment → converter smelting → tapping deoxidation alloying → LF refining furnace → calcium treatment → RH vacuum furnace → continuous casting, which is characterized in that it includes the following specific steps:

[0070] Step 1, converter smelting:

[0071] (1) Molten iron pretreatment operation: the molten iron entering the furnace is pretreated by desulfurization and cleaned of slag, wherein the S element content is 0.005%, and the S element content in scrap steel is 0.010%;

[0072] (2) Deep dephosphorization in the converter treatment process: the ...

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Abstract

The invention discloses a high-cleanliness pipeline steel smelting process. The process route comprises molten iron pouring, molten iron pretreatment, converter smelting, tapping, deoxidizing, alloying, LF refining furnace, treating with calcium, RH vacuum furnace and continuous casting and is characterized by comprising the following specific steps: firstly, converter smelting process; secondly, refining furnace smelting process; and thirdly, continuous casting process. The invention belongs to a steel-making process in the field of metallurgy and relates to a method for smelting and controlling a high-cleanliness pipeline steel. By molten iron desulphurization pretreatment, optimizing a converter tapping and deoxidizing system and a slagging system, LF refining furnace deep deoxygenation and reducing slag manufacturing processes, RH high-vacuum-degree degassing and inclusion removal process, the pouring is protected by the continuous casting in the whole process so that the composition of a casting billet is uniform, the contents of harmful elements such as S, P, O, N and H are low, the non-metallic inclusions are effectively controlled, the casting billet is good in internal quality and the production of high value-added ultra-low sulfur steel is ensured.

Description

technical field [0001] The invention belongs to the field of metallurgy and relates to a pipeline steel smelting process, in particular to a pipeline steel smelting process with high cleanliness. Background technique [0002] With the rapid development of pipeline steel demand industries such as oil and natural gas, the reliability requirements for pipeline steel pipes are getting higher and higher, not only requiring high strength, high low temperature crack arrest toughness and good weldability, but also for special areas. Pipeline steel also requires anti-H 2 S corrosion ability and large strain resistance. [0003] In sour gas environment, the main quality problems that lead to the failure of pipeline steel are hydrogen induced cracking (HIC) and sulfide stress corrosion cracking (SSCC). It is generally believed that HIC mostly originates from harmful elements and inclusions in molten steel, and the formation of SSCC is closely related to HIC. In order to improve the ...

Claims

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Application Information

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IPC IPC(8): C21C7/06C21C7/10C21C1/02C21C5/28B22D11/18
Inventor 曹余良蔡可森周桂成周贺贺张小伟朱安静
Owner NANJING IRON & STEEL CO LTD
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