Chang Ju Lee
Research Subjects
Chang Ju Lee has a total of 5 co-authors. Here are the top co-authors by number of shared publications:
- Il Dong Seo
Daedong Co. Ltd. 47-59, Dongbuk-ro 1109 beon-gil, Sangdong-myeon, Gimhae-si 50803, Gyeongsangnam-do, Korea
1 shared publication - Jong Bok Byun
Engineering Research Institute, School of Mechanical and Aerospace Engineering, Gyeongsang National University, Jinju 52828, Korea
1 shared publication - Man Soo Joun
ReCAPT, School of Mechanical and Aerospace Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea
1 shared publication - Mohd Kaswandee Razali
Graduate School of Mechanical and Aerospace Engineering, Gyeongsang National University (GNU), Gyeongnam, Jinju, 52828, Republic of Korea
1 shared publication - Wan Jin Chung
Department of Mechanical System Design Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
1 shared publication
Latest Publications
- Open Access
Automatic Multi-Stage Cold Forging of an SUS304 Ball-Stud with a Hexagonal Hole at One End
SUS304 stainless steel is characterized by combined tensile and compression testing, with an emphasis on flow stress at higher strain and temperature. The plastic deformation behavior of SUS304 from room temperature to 400 °C is examined and a general approach is used to express flow stress as a closed-form function of strain, strain rate, and temperature; this is optimal when the strain is high, especially during automatic multi-stage cold forging. The fitted flow stress is subjected to elastothermoviscoplastic finite element analysis (FEA) of an automatic multi-stage cold forging process for an SUS304 ball-stud. The importance of the thermal effect during cold forging, in terms of high material strength and good strain-hardening, is revealed by comparing the forming load, die wear and die stress predictions of non-isothermal and isothermal FEAs. The experiments have shown that the predictions of isothermal FEA are not feasible because of the high predicted effective stress on the weakest part of the die.
Open AccessAutomatic Multi-Stage Cold Forging of an SUS304 Ball-Stud with a Hexagonal Hole at One End
SUS304 stainless steel is characterized by combined tensile and compression testing, with an emphasis on flow stress at higher strain and temperature. The plastic deformation behavior of SUS304 from room temperature to 400 °C is examined and a general approach is used to express flow stress as a closed-form function of strain, strain rate, and temperature; this is optimal when the strain is high, especially during automatic multi-stage cold forging. The fitted flow stress is subjected to elastothermoviscoplastic finite element analysis (FEA) of an automatic multi-stage cold forging process for an SUS304 ball-stud. The importance of the thermal effect during cold forging, in terms of high material strength and good strain-hardening, is revealed by comparing the forming load, die wear and die stress predictions of non-isothermal and isothermal FEAs. The experiments have shown that the predictions of isothermal FEA are not feasible because of the high predicted effective stress on the weakest part of the die.