| 摘要 |
A plating layer containing 7.2-10.6 mass% Fe, 0.2-0.4 mass% Al, and 0.1 mass% Ni and the like, the balance comprising Zn and impurities, wherein a galvannealed steel plate having excellent press formability is characterized in being provided with the plating layer in which, in the vertical section of the plating layer, the average thickness of a ? phase is no greater than 0.2 µm, and the average thickness of a G phase that exists in contact with the base steel is no greater than 0.5 µm, and within the G phase, Ni and the like is contained at a ratio within the G phase of at least 0.5 mass%, the phase that exists in contact with the G phase being a mixed phase of a G1 phase and a d phase, the d phase ratio defined in the following equation being at least 10%: d phase ratio=( d phase/G phase contact interface length)/( d phase/ G phase contact interface length + G1 phase/G phase contact interface length) × 100, such that here, the d phase/G phase contact interface length is the length of the interface at which the d phase and the G phase are in contact, and the G1 phase/G phase contact interface length is the length of the interface at which the G1 phase and the G phase are in contact. |
