Influence of the Dew Point on the Coating Quality of GA TRIP steel
Galvannealing simulations were carried out on CMnSi TRIP steel after dipping in a Zn bath at 460 oC containing 0.13 mass-% Al.The galvannealing temperature was in the range of 540-570 oC.After the galvannealing of a panel annealed in a low dew point atmosphere (-60 oC),the coating layer consisted of delta and eta phase crystals.Al and the oxides formed during annealing were present at the steel/coating interface.After the galvannealing of a panel annealed in a higher dew point atmosphere (-10 oC and +5 oC),the coating layer consisted of delta phase crystals,and a thin layer of gamma phase crystals at the steel/coating interface.Two types of delta phase crystals were observed: coarse delta crystals and fine delta phase crystals.Al was detected mainly at the surface of the coating layer.Oxides were distributed throughout the coating layer.The reduction of the thickness of the surface oxides layer on panels annealed in a high DP gas atmosphere resulted in an increased Fe content at the surface of the coating layer.The improved coating quality of the panels annealed in higher dew point gas atmospheres was due to the formation of a thinner layer of oxides.A high dew point atmosphere can therefore significantly contribute to the decrease of Zn-coating defects on CMnSi TRIP steels processed in hot dip galvanizing/galvannealing lines.
Transformation Induced Plasticity (TRIP) Selective oxidation Dew point Galvannealing
CHO Lawrence LEE Seok-Jae KIM Myung Soo KIM Young Ha DE COOMAN Bruno C
Graduate Institute of Ferrous Technology,Pohang University of Science and Technology,Pohang 790-784, POSCO Technical Research Laboratories,Gwangyang,545-090,South Korea
国际会议
Asia Steel International conference 2012(第五届亚洲钢铁大会)
北京
英文
1-5
2012-09-23（万方平台首次上网日期，不代表论文的发表时间）