알루미늄과 마그네슘 첨가가 용융아연 도금강판 도금층의 미세조직과 경도에 미치는 영향 (Effects of Al and Mg on the Microstructure and Hardness of the Coating Layer of Hot-dip Galvanized Steel Sheet)

서지정보

· 발행기관 : 한국열처리공학회
· 수록지 정보 : 열처리공학회지 / 36권 / 4호 / 198 ~ 205페이지
· 저자명 : 성윤제, 김동규, 서준기, 한경현, 홍범기, 김강민, 허성욱, 박성현, 임재택, 손승배, 이석재, 정재길

초록

We investigated the effects of Al and Mg on the microstructure and hardness of the coating layer of galvanized steel sheets, by thermodynamic calculations, X-ray diffraction, scanning electron microscopy, and Vickers hardness tests of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers. Regardless of the alloy composition of the galvanizing bath, a Fe-Al layer was observed between the coating layer and steel sheet. The Zn- 0.2Al coating layer consists of major h.c.p. Zn phase and minor f.c.c. Al phase. The fraction of f.c.c. Al phase (containing a significant amount of Zn) of the coating layer increases with increasing the chemical composition of Al of the galvanizing bath. The h.c.p. MgZn2 phase was formed in the Al/Mg-containing Zn-6Al-2Mg and Zn-10Al- 5Mg coating layers, forming Zn-Al-MgZn2 eutectic microstructure. The primary MgZn2 phase was additionally formed in the Zn-10Al-5Mg coating layers containing high concentrations of Al and Mg. The Vickers hardness values of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers were 59.1 ± 1.2 HV, 161.2 ± 5.7 HV, and 215.5 ± 40.3 HV, respectively. The addition of Al and Mg increased the hardness of the coating layer by increasing the fraction of the Al phase (containing Zn) and MgZn2 intermetallic compound, which were harder than the Zn phase.

영어초록

We investigated the effects of Al and Mg on the microstructure and hardness of the coating layer of galvanized steel sheets, by thermodynamic calculations, X-ray diffraction, scanning electron microscopy, and Vickers hardness tests of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers. Regardless of the alloy composition of the galvanizing bath, a Fe-Al layer was observed between the coating layer and steel sheet. The Zn- 0.2Al coating layer consists of major h.c.p. Zn phase and minor f.c.c. Al phase. The fraction of f.c.c. Al phase (containing a significant amount of Zn) of the coating layer increases with increasing the chemical composition of Al of the galvanizing bath. The h.c.p. MgZn2 phase was formed in the Al/Mg-containing Zn-6Al-2Mg and Zn-10Al- 5Mg coating layers, forming Zn-Al-MgZn2 eutectic microstructure. The primary MgZn2 phase was additionally formed in the Zn-10Al-5Mg coating layers containing high concentrations of Al and Mg. The Vickers hardness values of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers were 59.1 ± 1.2 HV, 161.2 ± 5.7 HV, and 215.5 ± 40.3 HV, respectively. The addition of Al and Mg increased the hardness of the coating layer by increasing the fraction of the Al phase (containing Zn) and MgZn2 intermetallic compound, which were harder than the Zn phase.

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