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Steelmaking process capable of improving quality of U71Mn heavy rail steel product

A technology of product quality and heavy rail steel, applied in the direction of improving process efficiency and manufacturing converters, can solve problems such as difficult to meet transportation needs, achieve the effect of improving center shrinkage defects and eliminating white spots

Inactive Publication Date: 2015-12-09
HBIS COMPANY LIMITED HANDAN BRANCH COMPANY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

By the end of 2010, my country's railway mileage has reached 80,000 km, but it is still difficult to meet the huge transportation demand

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Example 1: The desulfurization and desulfurization time of molten iron is 30 minutes, the S content after treatment is 0.003% (mass fraction), the P content is 0.11% (mass fraction), and the temperature is 1280°C; the target C of the converter smelting end point is 0.06% (mass fraction), and P is 0.011 % (mass fraction), temperature 1620°C; 1 / 4 of the steel is tapped with low-nitrogen recarburizer, high-purity ferrosilicon, and metal manganese for deoxidation alloying, and the order of adding alloy and slag is low-nitrogen recarburizer, metal manganese , high-purity ferrosilicon and silicon-calcium-barium; after the LF refining molten steel enters the station, lime and fluorite are added to reduce the electricity and chemical slag, and then slag is added to make white slag. The white slag is kept for 15 minutes and the refining time is 45 minutes.

[0015] The continuous casting slab has a center shrinkage cavity of 0.5 grade and a center segregation of 0.5 grade after l...

Embodiment 2

[0017] The desulfurization and desulfurization time of molten iron is 35 minutes, the S content after treatment is 0.005% (mass fraction), the P content is 0.12% (mass fraction), and the temperature is 1300°C; ), the temperature is 1630°C; 1 / 4 of the steel is tapped with low-nitrogen carburizer, high-purity ferrosilicon, and metal manganese for deoxidation alloying. The order of alloy and slag addition is low-nitrogen carburizer, metal manganese, and high-purity silicon Iron and silicon-calcium-barium; LF refining molten steel is added to the station after lime and fluorite are added to reduce the electrolytic slag, and then slag is added to make white slag. The white slag is kept for 16 minutes and the refining time is 50 minutes.

[0018] The continuous casting slab has no central shrinkage cavity defect, 0.5 grade of central segregation, 0.5 grade of central loose defect after low power pickling inspection, no edge crack, corner crack, center crack and middle crack. After b...

Embodiment 3

[0020] The desulfurization and desulfurization time of molten iron is 40 minutes, the S content after treatment is 0.002% (mass fraction), the P content is 0.10% (mass fraction), and the temperature is 1350°C; ), the temperature is 1640°C; 1 / 4 of the steel is tapped with low-nitrogen carburizer, high-purity ferrosilicon, and metal manganese for deoxidation alloying. The order of alloy and slag addition is low-nitrogen carburizer, metal manganese, and high-purity silicon Iron and silicon-calcium-barium; LF refining molten steel is added to the station after lime and fluorite are added to reduce the electrolytic slag, and then slag is added to make white slag. The white slag is kept for 18 minutes and the refining time is 60 minutes.

[0021] The continuous casting slab has no central shrinkage cavity defect, no central segregation, central loose defect of 0.5 level, no edge crack, corner crack, center crack, and middle crack after low-power pickling inspection. After being roll...

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Abstract

The invention discloses a steelmaking process capable of improving the quality of a U71Mn heavy rail steel product, and belongs to the technical field of steelmaking processes. The steelmaking process comprises the process steps of molten iron desulfurization, converter smelting, LF refining, RH refining and special-shaped blank continuous casting, and is characterized in that a deep desulfurization mode is adopted for the molten iron desulfurization, wherein the desulfurization time is 30-40 min; and after the treatment, S is not more than 0.005% (mass fraction), [P] is not more than 0.120% (mass fraction), and T is not lower than 1250 DEG C. As the steelmaking process is adjusted and controlled according to the invention, the defects of center segregation, center porosity and center hole shrinkage of heavy rail steel cast blanks are prominently alleviated; the crack low-power defect of the cast blanks is effectively prevented; and the surface defectless rate of the heavy rail steel continuous cast blanks reaches 100%. The rolled heavy rail steel low-power structure prevents white dots, shrinkage residues, internal cracks, skull patches, delamination and inclusion visible to the naked eyes; the steel rail tensile strength is averagely higher than or equal to 900 MPa; and the steel rail tread hardness is higher than or equal to 260 HB.

Description

technical field [0001] The invention relates to a steelmaking process capable of improving the quality of U71Mn heavy rail steel products, and belongs to the technical field of steelmaking process. Background technique [0002] For a long time, my country's railway transport capacity has been in short supply, and the growth of railway passenger traffic has been severely restricted. Therefore, in the face of the demand for railway passenger transport, the demand for heavy rail has continued to grow. At present, heavy load, high speed and increased traffic density have become the main means to solve the contradiction between the volume and capacity of railway transportation in my country, and the domestic demand for rail steel is increasing day by day. By the end of 2010, my country's railway mileage has reached 80,000 km, but it is still difficult to meet the huge transportation demand. According to the "Medium and Long-term Railway Network Planning Adjustment Plan" announce...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/064C21C7/076C21C5/28
CPCY02P10/20
Inventor 许斌张义春安君辉
Owner HBIS COMPANY LIMITED HANDAN BRANCH COMPANY
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