High-strength steel having excellent brittle crack arrestability and welding part brittle crack initiation resistance, and production method therefor

Abstract

One aspect of the present invention provides a high-strength steel having excellent brittle crack arrestability and welding part brittle crack initiation resistance, and a production method therefor.According to one aspect of the present invention, provided are a high-strength steel having excellent brittle crack arrestability and welding part brittle crack initiation resistance, and a productionmethod therefor, the high-strength steel: comprising, in wt%, C: 0.05-0.09%, Mn: 1.5-2.0%, Ni: 0.3-0.8%, Nb: 0.005-0.04%, Ti: 0.005-0.04%, Cu: 0.1-0.5%, Si: 0.05-0.3%, Al: 0.005-0.05%, P: 100ppm or less, S: 40ppm or less, and a remainder made up by Fe and other inevitable impurities; having a center part microstructure comprising, in area%, 70% or more of acicular ferrite and 10% or less of pearlite, wherein the equivalent circular diameter of the pearlite is 15um (micrometers) or less; having , in a 2mm or less subsurface region, a microstructure comprising, in area%, 30% or more of one typeor more among ferrite and a remainder made up by bainite, martensite, and pearlite; and having a welding heat affected zone, which is formed when welding , that comprises, in area%, 5% or less of a martensite-austenite constituent. According to the present invention, high-strength steel having high yield strength, excellent brittle crack arrestability, and excellent welding part brittle crack initiation resistance may be obtained.

Description

technical field [0001] The present disclosure relates to a high-strength steel material having excellent brittle crack arrest and weld zone brittle crack initiation resistance and a method of manufacturing the same. Background technique [0002] Recently, in consideration of domestic and international design requirements for structures used in the fields of ships, marine transportation, construction, and civil engineering, the development of ultra-thick steel plates with high strength properties is required. [0003] In the case where high-strength steel is included in the structural design, using a steel plate having a relatively reduced thickness can easily perform machining and welding operations while economical benefits can be obtained due to reduction in structural weight. [0004] In general, in the case of high-strength steel, since the reduction rate decreases when producing a thick steel plate, it may not be able to deform sufficiently compared to a thin steel plat...

AI Technical Summary

Problems solved by technology

Therefore, there is a limit to economic efficiency deterioration

Images