Abstract: A louvered clamshell door assembly for the bottom of a preheating charging bucket includes a pair of doors which open by swinging outwardly and upwardly to discharge scrap metal from the bucket and which cooperably adjoin upon closing to retain scrap metal in the bucket. The doors include multiple stepped louvers which form the bottom weight-bearing surface of the charging bucket. The louvers of each door are supported by underlying chair support plates and are pivotably attached thereto to prevent jamming of scrap metal pieces between the louvers and to also permit thermal contraction and expansion of the louvers over many preheating cycles. Free convection of air through the louvers and scrap metal is facilitated by air deflectors attached to the chair support plates. Lateral shock absorption slots in the chair support plates improve the shock absorption capacity of the clamshell door assembly during loading of the bucket with scrap metal.