Prediction Model of Cleavage Fracture Toughness of Ferrite Steel
A numerical model to quantitatively predict a cleavage fracture toughness in ferrite-cementite steel is proposed based on a microscopic fracture initiation process of three stages; (I) formation of fracture origin by cementite cracking,(II) propagation of the cementite crack into ferrite matrix,and (III) propagation across ferrite grain boundary.The fracture condition of Stage (I) is formulated as a ratio of cementite cracking based on experimental results of a tensile testing with notched specimens and SEM observation.Stage (II) and Stage (III) conditions are formulated based on a concept of fracture stress criterion.In the numerical model,an active zone is divided into finite volume elements.Ferrite grains and cementite particles are assigned based on their distributions into each volume element.Strain and stress at each volume element are calculated by a macroscopic FEA.Fracture is assumed to initiate at the time when the fracture conditions of the all stages are satisfied in any one of the volume elements.The model is validated by three point bend testing with notched specimens.The predicted values of fracture toughness show good agreement with the experimental results.Therefore,the effectiveness of the proposed model is found out.
Cleavage fracture Fracture toughness Multiscale Fracture stress Ferrite
Kazuki Shibanuma Shuji Aihara Motoyuki Matsubara Hiroyuki Shirahata Tsunehisa Handa
Department of Systems Innovation,The University of Tokyo,Tokyo 113-8656,Japan Hanshin Plant,Kubota Corporation,Hyogo 660-0857,Japan Oita R&D Lab.,Nippon Steel & Sumitomo Metal Corporation,Oita 870-0992,Japan Joining & Strength Research Department,JFE Steel Corporation,Chiba 260-0835,Japan
国际会议
北京
英文
1-10
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）