Impact Toughness of Spring Steel after Bainite and Martensite Transformation

Metals

Min-Soo Suh¹  Seung-Hoon Nahm²  No-Keun Park³  Chang-Min Suh⁴ 

[1] Korea Institute of Energy Research, Daejeon 34129, Republic of Korea;Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea;School of Materials Science and Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea;School of Mechanical Engineering, Kyungpook Nat’l University, Daegu 41566, Republic of Korea;

关键词: spring steel;    electron backscatter diffraction;    bainite;    martensite;    austempering;    lath;   

DOI  :  10.3390/met12020304

来源: DOAJ

【 摘 要 】

It has been reported that a multiphase microstructure with bainite, martensite, and retained austenite obtained by austempering, or quenching and tempering of spring steel containing Si, Mn, and Cr exhibits high strength and ductility. However, little research has been conducted on the bainite formation and impact fracture behavior of next-generation spring steel from the perspective of engineering and industrial applications. The microstructural transformation characteristics of bainite and martensite related to the heat treatment cycle on the maker side were quantitatively analyzed using electron backscatter diffraction (EBSD) and scanning electron microscopy (SEM) analyses. Moreover, the effects and mechanical properties of bainite and martensite formation in response to changes in lath length and width were studied and analyzed. That is, to obtain the mechanical properties of spring steel with the highest quality, tensile and impact specimens, whose microstructure and notch shape change according to the heat-treatment cycle, were prepared and studied.

【 授权许可】

Unknown