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355MPa yield strength steel sheet for high heat input welding and manufacturing method thereof

A technology for high-energy welding and yield strength, applied in metal rolling and other directions, can solve the problems of high cost, low performance, low production efficiency, etc., and achieve the effects of improving low-temperature toughness, inhibiting roughening, and improving low-temperature impact toughness.

Active Publication Date: 2019-02-12
NORTHEASTERN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to provide a steel plate for large heat input welding with a yield strength of 355MPa and its preparation method, which solves the problem of low performance of conventional steel plates under large heat input welding conditions, and solves the problem of the existing large heat input welding steel plate. Problems of low production efficiency and high cost

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  • 355MPa yield strength steel sheet for high heat input welding and manufacturing method thereof

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Embodiment 1

[0032] In this embodiment, the steel plate for high heat input welding with a yield strength of 355 MPa, its chemical composition is calculated by mass fraction, including: C 0.05%, Si 0.2%, Mn 1.5%, P 0.005%, S 0.005%, Nb 0.03%, Ti 0.025%, N0.003%, O 0.002%, Al 0.005%, Ca 0.0005%, Mg 0.0001%, the balance is Fe; among the inclusions with a size of 0.5-5μm in the steel plate, Ti-Al-Ca-Mn- The number of O-S composite inclusions accounts for 15%; Ti-Al-Ca-Mn-O-S composite inclusions contain an average of 15% Ti, 10% Al, and 5% Ca in terms of mass fraction, and 20% of the inclusions contain magnesium. Aluminum spinel inclusions, the outer layer contains Ca oxysulfide and Mn sulfide.

[0033] The production method of the above-mentioned steel plate comprises the following steps: using deep desulfurized molten iron for smelting, adding silicon-manganese alloy into the ladle when tapping 1 / 4 of the steel in the converter, adding ferro-titanium when tapping 1 / 2, and the oxygen content...

Embodiment 2

[0037] In this embodiment, the steel plate for high heat input welding with a yield strength of 355 MPa, its chemical composition is calculated by mass fraction, including: C 0.12%, Si 0.25%, Mn 1.25%, P 0.008%, S 0.002%, Nb 0.02%, Ti 0.015%, N0.006%, O 0.005%, Al 0.01%, Ca 0.002%, Mg 0.0005%, the balance is Fe; among the inclusions with a size of 0.5-5μm in the steel plate, Ti-Al-Ca-Mn- The number of O-S composite inclusions accounts for 50%; Ti-Al-Ca-Mn-O-S composite inclusions contain an average of 21% Ti, 15% Al, and 12% Ca in terms of mass fraction, and 16% of the inclusions contain magnesium. Aluminum spinel inclusions, the outer layer contains Ca oxysulfide and Mn sulfide.

[0038] The production method of the steel plate includes the following steps: smelting with deep desulfurized molten iron, adding silicon-manganese alloy to the ladle when 1 / 3 of the steel is tapped from the converter, adding ferro-titanium when 1 / 2 of the steel is tapped, and the oxygen content of ...

Embodiment 3

[0042] In this embodiment, the steel plate for high heat input welding with a yield strength of 355MPa, its chemical composition is calculated by mass fraction, including: C 0.15%, Si 0.1%, Mn 1.0%, P 0.01%, S 0.008%, Nb 0.005%, Ti 0.005%, N0.007%, O 0.006%, Al 0.015%, Ca 0.005%, Mg 0.001%, the balance is Fe; among the inclusions with a size of 0.5-5μm in the steel plate, Ti-Al-Ca-Mn- The number of O-S composite inclusions accounts for 60%; Ti-Al-Ca-Mn-O-S composite inclusions contain an average of 10% Ti, 8% Al, and 10% Ca by mass fraction, and 30% of the inclusions contain magnesium Aluminum spinel inclusions, the outer layer contains Ca oxysulfide and Mn sulfide.

[0043] The above steel plate production method includes the following steps: smelting with deep desulfurized molten iron, adding silicon-manganese alloy to the ladle when 1 / 2 of the steel is tapped from the converter, and adding ferro-titanium when 3 / 4 of the steel is tapped, and the oxygen content of the molten ...

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Abstract

The invention belongs to the technical field of low-alloy high-temperature steels, and particularly relates to 355MPa yield strength steel sheet for a high heat input welding and a manufacturing method thereof. The steel sheet comprises the following chemical components in percent by mass: 0.05-0.15% of C, 0.1-0.3% of Si, 1.0-1.6% of Mn, 0.001-0.01% of P, 0.001-0.008% of S, 0.004-0.04% of Nb, 0.005-0.025% of Ti, 0.002-0.007% of N, 0.001-0.006% of O, 0.001-0.015% of Al, 0.0005-0.005% of Ca, 0.0001-0.001% of Mg, and the balance Fe, wherein Ti-Al-Ca-Mg-O-S composite inclusion accounts for more than 10% of 0.5-5 microns inclusions in the steel sheet; and the steel sheet is composed of special components. The manufacturing method comprises the following steps: adding silicomanganese and ferrotitanium for deoxidation alloying during deoxidation; performing desulfuration on LF refining white slag; processing through a calcium feeding line; and controlling to roll and cool a continuous castingin two stages. According to the technical scheme, the 355MPa yield strength steel sheet for the high heat input welding and the manufacturing method thereof are high in production efficiency; the alloy adding amount is saved; the effect of refining an HAZ structure effect through the inclusion is obvious; the low-temperature toughness in high heat input welding is outstanding; and the popularization and application are conveniently carried out.

Description

technical field [0001] The invention belongs to the technical field of low-alloy high-strength steel, and in particular relates to a steel plate for large heat input welding with a yield strength of 355 MPa and a preparation method thereof. Background technique [0002] With the large-scale development of steel structures in the fields of construction, energy, shipbuilding, and marine engineering, the strength and thickness of the steel plates used have increased significantly, and the production scale has expanded rapidly. Usually, the welding workload for building such large structures accounts for about 10% of the total workload. 30-40% of that. Therefore, on the premise of ensuring the welding quality, how to improve the welding efficiency is the key to realize low-cost and economical manufacturing. The steel plate for welding with high input energy can reduce the number of welding passes and improve the efficiency. For example, for a 40mm thick ordinary steel plate, i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/12C22C38/14C22C38/02C22C38/04C22C38/06C22C33/04C21C7/06C21C7/068C21C7/00B21B1/46B21C37/02
CPCB21B1/46B21C37/02C21C7/0006C21C7/0056C21C7/06C21C7/068C22C33/04C22C38/002C22C38/02C22C38/04C22C38/06C22C38/12C22C38/14
Inventor 王昭东贾国生王丙兴李玉谦王超王彦祥王国栋陈子钢
Owner NORTHEASTERN UNIV