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ISSN : 1225-0562(Print)
ISSN : 2287-7258(Online)
Korean Journal of Materials Research Vol.28 No.11 pp.663-670
DOI : https://doi.org/10.3740/MRSK.2018.28.11.663

Correlation between Microstructure and Mechanical Properties of the Additive Manufactured H13 Tool Steel

Woojin An1, Junhyeok Park1, Jungsub Lee1, Jungho Choe2, Im Doo Jung2, Ji-Hun Yu2, Sangshik Kim1 , Hyokyung Sung1†
1Department of Materials Engineering and Convergence Technology, ReCAPT, Gyeongsang National University, Jinju 52828, Republic of Korea
2Powder & Ceramics Division, Korea Institute of Materials Science, Sang Nam Dong 66, Changwon 51508, Republic of Korea
Corresponding author
E-Mail : hksung@gnu.ac.kr (H. Sung, Gyeongsang Nat'l Univ.)

Abstract

H13 tool steels are widely used as metallic mold materials due to their high hardness and thermal stability. Recently, many studies are undertaken to satisfy the demands for manufacturing the complex shape of the mold using a 3D printing technique. It is reported that the mechanical properties of 3D printed materials are lower than those of commercial forged alloys owing to micropores. In this study, we investigate the effect of microstructures and defects on mechanical properties in the 3D printed H13 tool steels. H13 tool steel is fabricated using a selective laser melting(SLM) process with a scan speed of 200 mm/ s and a layer thickness of 25 μm. Microstructures are observed and porosities are measured by optical and scanning electron microscopy in the X-, Y-, and Z-directions with various the build heights. Tiny keyhole type pores are observed with a porosity of 0.4%, which shows the lowest porosity in the center region. The measured Vickers hardness is around 550 HV and the yield and tensile strength are 1400 and 1700 MPa, respectively. The tensile properties are predicted using two empirical equations through the measured values of the Vickers hardness. The prediction of tensile strength has high accuracy with the experimental data of the 3D printed H13 tool steel. The effects of porosities and unmelted powders on mechanical properties are also elucidated by the metallic fractography analysis to understand tensile and fracture behavior.

적층 제조된 H13 공구강의 미세조직과 기계적 특성간의 상관관계

안우진1, 박준혁1, 이정섭1, 최중호2, 정임두2, 유지훈2, 김상식1, 성효경1†
1경상대학교 나노신소재융합공학과, 2한국기계연구원 부설 재료연구소, 분말/세라믹연구본부

초록

 

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