Steel material for welding

A technology of steel and content, applied in welding media, welding equipment, welding/cutting media/materials, etc., can solve the problems of low limit value and inability to obtain high strength, and achieve the effect of excellent fracture toughness and excellent CTOD characteristics

Inactive Publication Date: 2014-07-23
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] However, at this time, P CTOD and CeqH limit values ​​are low, so it is necessary to greatly limit the amount of alloy components that can be added
Therefore, it is impossible to obtain high-strength steel with a plate thickness of 6-100mm commonly used in structural materials.

Method used

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  • Steel material for welding
  • Steel material for welding
  • Steel material for welding

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0048] In the present embodiment, B is added to refine the microstructure of the FL portion as described above. B segregates at the prior-austenite grain boundaries to lower the grain boundary energy, thereby significantly delaying the ferrite transformation of steel. Therefore, structures such as coarse ferrite formed from grain boundaries are suppressed by the HAZ structure having coarse austenite grains. In addition, the microstructure of the FL portion becomes Significantly fine. Its purpose is to suppress the phase change at the grain boundary due to solid-solution B, and to facilitate ferrite transformation from the oxide-based non-metallic inclusions existing in the crystal grains in the form of transformation nuclei. Thereby IGF increases. In addition, since coarse inclusions become the starting point of fracture, it is necessary to reduce coarse inclusions, and fine inclusions are preferable as transformation nuclei.

[0049] In order to obtain the above effects, ...

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PUM

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Abstract

This steel material for welding has a steel component in which: PCTOD is 0.065% or less, CeqH is 0.225% or less, FB is 0.0003% or more, and Bp is 0.09% to 0.30%; and at the plate-thickness center portion in the cross-section in the plate thickness direction, oxide particles having an equivalent circle diameter of no less than 2 mum are present in numbers of no more than 20 per mm2, and Ti oxides having an equivalent circle diameter of 0.05 to 0.5 mum are present in numbers of 1.0 103 to 1.0 105 per mm2.

Description

technical field [0001] The present invention relates to a welding steel material excellent in CTOD characteristics of welding heat affected zone (Heat Affected Zone; HAZ) from low heat input welding (also called small heat input welding) to medium heat input welding (also called mid line energy welding) and its The manufacturing method, especially relates to the FL part (welding fusion line, Fusion Line), which is the boundary between WM (welding metal) and HAZ (welding heat-affected zone), and the IC part (critical temperature) where the toughness is most deteriorated during low heat input welding to medium heat input welding. Intercritical HAZ) is a steel material for welding that has excellent CTOD properties at the boundary between HAZ and BM (base metal) and exhibits excellent toughness. [0002] this application claims priority based on Japanese Patent Application No. 2011-257688 for which it applied in Japan on November 25, 2011, and uses the content here. Background ...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): C22C38/00B21B3/00B22D11/00B22D11/124C21D8/02C22C38/16
CPCC22C38/001B23K35/30B23K35/3053B23K35/3073C21D8/02C22C38/00C22C38/002C22C38/008C22C38/02C22C38/04C22C38/08C22C38/12C22C38/14C22C38/16C22C38/60
Inventor福永和洋渡部义之臼井真介千千岩力雄
OwnerNIPPON STEEL CORP