Unlock instant, AI-driven research and patent intelligence for your innovation.

Steel with excellent toughness in the welded heat-affected zone

A technology of steel and inclusions, applied in the field of steel, can solve the problems of HAZ toughness deterioration, difficulty in obtaining dispersion effect, uneven concentration of Ti and N, etc.

Inactive Publication Date: 2012-02-01
KOBE STEEL LTD
View PDF3 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, only the addition of Ti and N is controlled, and the concentration of Ti and N is not uniform during the solidification of molten steel, and it is difficult to obtain a sufficient dispersion effect.
Especially in the final solidification zone, etc., Ti and N are concentrated, and coarse TiN is precipitated in molten steel, so the HAZ toughness deteriorates on the contrary.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Steel with excellent toughness in the welded heat-affected zone
  • Steel with excellent toughness in the welded heat-affected zone
  • Steel with excellent toughness in the welded heat-affected zone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0021] The inventors of the present invention have studied factors affecting HAZ toughness during high heat input welding from various angles. As a result, it was found that the main reason for the deterioration of HAZ toughness is the existence of coarse Ti-containing inclusions, such Ti-containing inclusions are mainly TiN or TiO crystallized during the solidification stage of molten steel. 2 .

[0022] The following considerations can be made regarding the formation process of the above-mentioned coarse Ti-containing inclusions and the factors that cause the HAZ toughness to be deteriorated by such inclusions. First, deoxidation is performed by adding Al to molten steel, and as a result, Al in a flattened (flat) shape is dispersed in molten steel 2 o 3 The solid, at the liquidus temperature (for example, below 1535 ° C), a solid δ phase or γ phase is generated from a part of the molten steel, and Ti, N, and S are thickened in the rest of the liquid phase. Then, if the so...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention relates to a steel material which satisfies the specified chemical composition. The following impurities are dispersed: when the length at maximum width is set as the size of the impurity along the maximum projection length direction of the impurity when observing the impurity perpendicular to a microscope, the size is more than 2Mum and the impurities satisfy the following formulas (1) (2). The generation of massive TiN is prevented and the HAZ toughness is excellent. 0.01<=[Ca] / [Al]<=0.50...(1), 0.08<=([CaO]+[CaS]) / ([A]2O3])<=1.80...(2), wherein [Ca], [Al], [CaO], [CaS] and [Al2O3} respectively represent the content (mass%) of the Ca, Al, CaO, CaS and Al2O3 in the impurity.

Description

technical field [0001] The present invention relates to steel materials suitable for welded structures such as bridges, high-rise buildings, and ships, especially steel materials having excellent toughness in the heat-affected zone (hereinafter simply referred to as "HAZ") after high heat input welding. Background technique [0002] In recent years, with the increase in the size of the above-mentioned various welded structures and the promotion of thicker steel materials, from the viewpoint of reducing manufacturing costs and improving work efficiency, the welding input energy exceeds 400kJ / cm. Welding is applied. [0003] However, if large heat input welding is performed, the HAZ will be kept in the high-temperature austenite (γ) region for a long time and then slowly cooled, so the γ growth during heating is likely to cause coarse ferrite (α) in the cooling process. This coarsening of the structure typified by the formation of crystal grains has a problem that the toughne...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/14
CPCC22C38/002C22C38/005C22C38/02C22C38/04C22C38/06C22C38/14
Inventor 加藤拓太田裕己
Owner KOBE STEEL LTD