Abstract: A hot-dip Zn—Al alloy coated steel sheet exhibiting a beautiful coating appearance with metallic luster, in which no spangle or very fine spangles are formed, and having excellent blackening resistance and a method for manufacturing the hot-dip Zn—Al alloy coated steel sheet are provided. The hot-dip Zn—Al alloy coated steel sheet includes a hot-dip Zn—Al alloy coating layer containing 1.0 to 10 percent by mass of Al, 0.2 to 1.0 percent by mass of Mg, 0.005 to 0.1 percent by mass of Ni, and the balance being Zn and incidental impurities on at least one surface of a steel sheet. The manufacturing method includes the steps of dipping the steel sheet into a hot-dip Zn—Al alloy coating bath and pulling up and cooling the steel sheet, wherein the steel sheet pulled up from the coating bath is cooled to 250° C. at a cooling rate of 1° C. to 15° C./sec.

Abstract: A hot-dip Zn—Al alloy coated steel sheet exhibiting a beautiful coating appearance with metallic luster, in which no spangle or very fine spangles are formed, and having excellent blackening resistance and a method for manufacturing the hot-dip Zn—Al alloy coated steel sheet are provided. The hot-dip Zn—Al alloy coated steel sheet includes a hot-dip Zn—Al alloy coating layer containing 1.0 to 10 percent by mass of Al, 0.2 to 1.0 percent by mass of Mg, 0.005 to 0.1 percent by mass of Ni, and the balance being Zn and incidental impurities on at least one surface of a steel sheet. The manufacturing method includes the steps of dipping the steel sheet into a hot-dip Zn—Al alloy coating bath and pulling up and cooling the steel sheet, wherein the steel sheet pulled up from the coating bath is cooled to 250° C. at a cooling rate of 1° C. to 15° C./sec.

Abstract: A galvannealed steel sheet having a superior spot weldability characteristic in which the steel sheet has a base steel sheet cold-rolled from a material containing 0.005 wt % or less of C, 0.005 to 0.05 wt % of Ti, 0.01 to 0.1 wt % of Al, 0.005 to 0.015 wt % of Nb and 0.0002 to 0.002 wt % of B. In the process for making, the hot-dip plating layer applied after the alloying heat treatment has an Fe content of from 9 wt % to 12 wt %.