啮出弧 arc of recess

电弧炉出渣门 [冶] arc furnace slagging door

电弧炉出钢槽 [冶] arc furnace spout

电弧炉出烟弯管 [冶] arc furnace fume elbow

状态转移弧输出 state transition-arc output

伸高弧形出水嘴 extended curved spout