460 MPa极地船舶用钢及焊接接头低温力学性能  

Low temperature mechanical properties of 460MPa polar ship steel and its welded joints

作　　者：王超逸 洪晓莉 严玲 张红岩 高珍鹏 刘鑫 WANG Chaoyi;HONG Xiaoli;YAN Ling;ZHANG Hongyan;GAO Zhenpeng;LIU Xin(State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan 114009,Liaoning,China;Ansteel Beijing Research Institute Co.,Ltd.,Beijing 102200,China;Qingdao NMEI Group Co.,Ltd.,Qingdao 266000,Shandong,China;Luoyang Ship Material Research Institute,Luoyang 471023,Henan,China)

机构地区：[1]海洋装备用金属材料及其应用国家重点实验室,辽宁鞍山114009 [2]鞍钢集团北京研究院有限公司,北京102200 [3]青岛海检集团有限公司,山东青岛266000 [4]中国船舶重工集团公司第七二五研究所,河南洛阳471023

出　　处：《中国冶金》2024年第7期58-67,共10页China Metallurgy

基　　金：国家重点研发计划资助项目(2021YFB3701701)。

摘　　要：极地船舶用钢及其焊接接头必须在低温环境下安全服役。为了研究极地低温环境对高强度极地船舶用钢及其焊接接头性能的影响,使用控轧控冷工艺(TMCP)生产了54 mm厚的460 MPa强度级别极地船舶用低温钢,采用埋弧自动焊(SMA)工艺对钢板进行焊接试验,分析母材、焊缝中心及焊接热影响区(HAZ)的组织形貌,测试母材及焊接接头在低温环境下的强度、断裂韧性及疲劳性能。结果表明,母材的组织以多边形铁素体(PF)、珠光体(P)及粒状贝氏体(GB)为主;焊接接头中心组织主要由针状铁素体(AF)和粒状贝氏体(GB)构成,焊接熔合线清晰,热影响粗晶区(CGHAZ)组织以贝氏体(B)为主,晶粒较粗大,热影响细晶区(FGHAZ)则呈现正火态组织。温度直接影响着极地船舶用钢母材及其焊接接头的力学性能。随着温度的下降,母材及焊接接头的强度上升、冲击功下降,在-70℃极端低温环境下,母材的屈服强度可达500 MPa以上;-10℃时,母材、焊缝中心、热影响区裂纹尖端张开位移(CTOD)的断裂最大值δ;m;分别为1.18、1.11、0.98 mm;随着温度的降低,材料抗断裂的能力显著下降,-40℃时,母材、焊缝中心、热影响区CTOD的脆性失稳值δ;u;分别为0.62、0.70、0.32 mm;在-70℃极端低温环境下,热影响区试样发生脆性断裂。母材的疲劳性能优于焊接接头,低温能提升材料抗拉强度,同时也能提升材料的疲劳极限强度。对于极地船舶用低温钢,必须重视焊接工艺和焊接质量,进而提高焊接接头的实际低温应用性能。The steel used for polar ships and its welded joints must be safely served at low temperatures.In order to study the effect of polar low temperature environment on the properties of ultra-high strength polar ship steel and its welded joints,the 460MPa strength grade low temperature steel with thickness of 54mm for polar ships was produced by thermo-mechanical control process(TMCP),and welding tests were conducted by submerged arc automatic welding(SMA)process.The microstructure of base metal,welded line and welding heat affected zone(HAZ)was analyzed.The tensile strength,fracture toughness and fatigue limit strength of base metal and welded joint were tested at low temperature.The results show that the microstructure of base metal is mainly composed of polygonal ferrite(PF),pearlite(P)and granular bainite(GB).In the welded joint prepared by submerged arc automatic welding,the center structure of the weld is mainly composed of acicula ferrite(AF)and granular bainite(GB),the welding fusion line is clear,the coarse grain heat affected zone(CGHAZ)structure is mainly bainite(B)with coarse grains,and the fine grain heat affected zone(FGHAZ)shows a normal microstructure.The temperature directly affects the mechanical properties of base metal and its welded joints used in polar ships.With the decrease of temperature,the strength of base metal and welded joint increases and the impact work decreases.Under the extreme low temperature environment of-70℃,the yield strength of base metal can reach more than 500MPa.At-10℃,the characteristic valuesδmof crack tip opening displacement(CTOD)of base metal,welded line and heat affected zone are 1.18,1.11and 0.98mm,respectively.With the decrease of temperature,the fracture resistance of the material decreases significantly.At-40℃,the CTOD characteristic valuesδuof base material,welded line and heat affected zone are 0.62,0.70and 0.32mm,respectively.In the extreme low temperature environment of-70℃,brittle fracture occurs in the samples of the heat affected zone.The fatigue

关 键 词：极地船舶用钢 控轧控冷 低温性能 热影响区 裂纹尖端张开位移 

分 类 号：U668.2[交通运输工程—船舶及航道工程] U671.8[交通运输工程—船舶与海洋工程] TG407[金属学及工艺—焊接]