Effects of Orthogonal Heat Treatment on Microstructure and Mechanical Properties of GN9 Ferritic/Martensitic Steel  

作　　者：Tingwei Ma Xianchao Hao Ping Wang 

机构地区：[1]Key Laboratory of Electromagnetic Processing of Materials,Ministry of Education,Northeastern University,Shenyang 110004,China [2]Yingkou Institute of Technology,Yingkou 115014,China [3]CAS Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China

出　　处：《Chinese Journal of Mechanical Engineering》2023年第6期289-300,共12页中国机械工程学报（英文版）

基　　金：Supported by Natural Science Foundation Guidance Plan of Liaoning Province of China(Grant No.2019-ZD-0362);CAS Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences(Grant No.2021NMSAKF02).

摘　　要：Microstructure and mechanical properties of GN9 Ferritic/Martensitic steel for sodium-cooled fast reactors have been investigated through orthogonal design and analysis.Scanning electron microscopy(SEM),transmission electron microscopy(TEM),differential scanning calorimeter(DSC),tensile and impact tests were used to evaluate the heat treatment parameters on yield strength,elongation and ductile-to-brittle transition temperature(DBTT).The results indicate that the microstructures of GN9 steel after orthogonal heat treatments consist of tempered martensite,M23C6,MX carbides and MX carbonitrides.The average prior austenite grains increase and the lath width decreases with the austenitizing temperature increasing from 1000°C to 1080°C.Tempering temperature is the most important factor that influences the dislocation evolution,yield strength and elongation compared with austenitizing tempera-ture and cooling methods.Austenitizing temperature,tempering temperature and cooling methods show interactive effects on DBTT.Carbide morphology and distribution,which is influenced by austenitizing and tempering tempera-tures,is the critical microstructural factor that influences the Charpy impact energy and DBTT.Based on the orthogo-nal design and microstructural analysis,the optimal heat treatment of GN9 steel is austenitizing at 1000°C for 0.5 h followed by air cooling and tempering at 760°C for 1.5 h.

关 键 词：Ferritic/Martensitic steel Orthogonal design M23C6 carbide Ductile-to-brittle transition temperature 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG156[金属学及工艺—金属材料]