maintaining heat meaning in English

维持热

When flux appears liquid and transparent on both tube and valve , start sweeping flame back and forth along axis of joint to maintain heat on parts to be joined , especially toward the base of the valve socket
当管道和阀门上的焊剂都变成液状和透明时，则开始沿着连接轴向前后来会扫着火焰，保持连接部件的温度，特别是阀门承插口底部的温度。
When flux appears liquid and transparent on both tube and valve , start sweeping flame back and forth along axis of joint to maintain heat on parts to be joined , especially toward base of valve socket
当焊剂变成液态并且在管道和阀门上呈现半透明状态时，开始将火焰沿着连接部件的轴线进行进退烘烤，以保持连接部件、特别是阀门套筒底座部位的热度。