Microstructure and mechanical properties of an Nb-microalloyed EH47 steel  

作　　者：LU Xiaohui GAO Shan ZHANG Caiyi 

机构地区：[1]Research Institute,Baoshan Iron&Steel Co.,Ltd.,Shanghai 201999,China

出　　处：《Baosteel Technical Research》2023年第2期15-28,共14页宝钢技术研究（英文版）

摘　　要：The loading capacity of ultralarge container ships has reached 24000 TEUs so far,and to ensure the safe operation of these ships,the maxmium thickness of crack arrest steel used in the upper deck areas reaches 100 mm,and crack arrest toughness(K_(ca))needs to be>8000 N/mm^(3)/2.The EH47 steel was employed to study the effect of Nb on the phase transformation of supercooled austenite in the continuous cooling process after rolling and the effect of Nb on microstructure and mechanical properties of the crack arrest steel plate.It was found that the addition of 0.02%Nb can inhibit the ferrite transformation,improve the steel plate strength,and reduce the strength inhomogeneity in the thickness direction.Industrial production of 100 mm-thick EH47 was carried out based on the function of Nb in EH47 steel,and the test results reveal that high-strength EH47 shipbuilding plates with high toughness,excellent fracture and crack arrest toughness,and good welding properties can be produced using Nb-microalloyed composition design and the thermal mechanical control process(TMCP);furthermore,the value of the crack arrest toughness reached 9450.7 N/mm^(3/2) at-10℃.

关 键 词：EH47 crack arrest steel MICROALLOY crack arrest toughness 

分 类 号：TG142.1[一般工业技术—材料科学与工程]