The control range of 1Mg Mg is flammable metal, and there will be burning loss during smelting operation. When determining the control range of Mg, the error caused by burning loss should be considered, but not too wide, so as not to lose control of the alloy properties. We control the fluctuation range of Mg to 0 according to our experience and the level of ingredients, smelting and testing. Within 04%, the T5 profile is set as 0. 47% ~ 0. 50%, T6 section is 0. 57% ~ 0. 60%.