Bottom gating pouring time, it is the time for liquid metal filled in the mold from bottom to top, thus avoiding the splashing and oxidation associated with vertical gating. And is denoted by Tbg. Bottom Gating Pouring Time is usually measured using the Second for Time. Note that the value of Bottom Gating Pouring Time is always positive. Typically, the value of Bottom Gating Pouring Time is greater than 0.