Rolled steel with excellent toughness of sparkling heat effect section and manufacturing method thereof

A technology of welding heat effect and manufacturing method, applied in the field of steel, to achieve the effect of suppressing the fluctuation of toughness and preventing the deterioration of toughness

Inactive Publication Date: 2014-06-18
KOBE STEEL LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In addition, although there is no technology aimed at improving HAZ toughness, Patent Document 4 proposes to contain elements such as REM and Zr in steel materials, and actively contain solid-solution REM and solid-solution Zr, thereby preventing hydrogen resistance. A technology that improves the internal quality of thick steel plates and ensures the soundness of internal quality by ultrasonic flaw detection

Method used

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  • Rolled steel with excellent toughness of sparkling heat effect section and manufacturing method thereof
  • Rolled steel with excellent toughness of sparkling heat effect section and manufacturing method thereof
  • Rolled steel with excellent toughness of sparkling heat effect section and manufacturing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0077] After primary refining of molten iron in a 240-ton converter, steel is tapped from the converter to ladles, and secondary refining is performed while adjusting the composition and temperature.

[0078] In the ladle, according to the deoxidation method shown in the following table 1, adjust to the total oxygen amount [O] shown in the following table 1 1 , while adjusting the chemical composition. Total oxygen [O] 1 This means that the amount of oxygen contained as dissolved atoms in molten steel and the amount of oxygen present as oxide-based inclusions combined together, and the amount of oxygen contained as dissolved atoms in molten steel, use a solid electrolyte The oxygen sensor is used for measurement, and the total oxygen content is measured by general inert gas melting-infrared absorption method. Also, in Table 1 below, except for the total oxygen amount [O] 1 In addition, the amount of dissolved oxygen in the molten steel before adding REM and Zr is also shown...

experiment example 2

[0112] The steel slabs of No. 3, No. 4, No. 8, No. 14, and No. 20 obtained in Experimental Example 1 above were hot-rolled to obtain steel plates with a thickness of 30 mm.

[0113] For a section perpendicular to the rolling direction of the obtained steel sheet, the composition of the inclusions was quantitatively analyzed under the same conditions as in Experimental Example 1 above, and the moles of each element contained in the inclusions to be analyzed were calculated. ratio. The observation position is D / 4 of the steel plate (where D is the thickness of the steel plate), and the observation conditions are except that the observation field area is 1cm 2 Other than that, the conditions are the same as those of the above-mentioned experimental examples. The calculation results of the molar ratio are shown in Table 5 below. Blank columns in Table 5 below indicate that they were not detected.

[0114] Next, in order to evaluate the toughness of the HAZ affected by heat duri...

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Abstract

A steel material having excellent weld HAZ(Heat-Affected Zone) toughness and a manufacturing method of the same are provided to prevent toughness degradation of the HAZ, and reduce amounts of solid solution REM and of solid solution Zr, thereby restricting the change of the HAZ toughness. A steel material having excellent weld heat-affected zone toughness comprises C : 0.01 to 0.2 %, Si : less than 0.5 %, Mn : less than 2.5 %, Ti : less than 0.03 %, N : less than 0.01 %, P : less than 0.02 %, S : less than 0.015 %, Al : less than 0.01 %, REM : 0.0010 to 0.1 %, Zr : 0.001 to 0.05 %, and the remainder Fe, and unavoidable impurities. Inclusions have REM and Zr, which REM is less than 0.0010 %, and Zr is less than 0.0010 %.

Description

technical field [0001] The present invention relates to steel materials used on structures such as bridges, high-rise buildings, ships, etc., and more specifically relates to the treatment of parts affected by heat (hereinafter referred to as "welding heat-affected zone" or "HAZ") during welding. ") steel with improved toughness and its manufacturing method. Background technique [0002] The properties required for steel materials used in bridges, high-rise buildings, ships, etc. have become increasingly stringent in recent years, and particularly good toughness is required. Most of these steel materials are generally joined by welding, but especially HAZ is affected by heat during welding, and there is a problem that the toughness tends to deteriorate. The greater the heat energy during welding, the more remarkable the deterioration of toughness appears. The reason for this is considered to be that when the heat energy during welding increases, the cooling rate of the HAZ ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/14
CPCC22C38/005C22C38/02C22C38/04C22C38/06C22C38/14
Inventor 出浦哲史杉村朋子水渡英昭井上亮
Owner KOBE STEEL LTD
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