The invention provides an alloyed
zinc aluminum
magnesium alloy coated steel plate and a production method thereof. The
coating has an
Fe content of not more than 5%, the
coating surface contains an MgZn2 phase, which has a particle size of not greater than 5 micrometers. The
coating surface is in the form of equiaxed grains, and in the coating, Mg accounts for 1.5-8wt%, aluminum accounts for 1.5-15wt%, and
rare earth accounts for 0-0.2wt%. According to the production method, cold rolled
strip steel is subjected to
continuous annealing and hot dipping in a continuous hot dip galvanizing unit, and then
alloy treatment is carried out on the hot-dip galvanized
zinc aluminum
magnesium steel plate. Chemically, a plating solution comprises 1.0-11wt% of Al, 0.5-5wt% of Mg, and the balance Zn and inevitable impurities. After the steel plate undergoes annealing by N2 containing 0.5%-30 vol % of H2, the steel plate is immersed in the plating solution at a temperature of 450-650DEG C, the steel plate enters a
zinc pot at 420-580DEG C, and the immersion plating time of the steel plate in the plating solution is 1-10s. After
air knife cooling, the zinc aluminum
magnesium steel plate enters an alloying furnace to undergo alloying treatment, the alloying temperature is 450-650DEG C, the alloying time is 3-20s, and then the steel plate is cooled at a speed of 10-50DEG C / s. The steel plate provided by the invention ensures that the coating does not fall off in a complex forming process, and after forming, the zinc aluminum magnesium coating can put its excellent
corrosion resistance to good use, thus prolonging the service life of components.