steel rust removing

例句：

1. 1. The steel wasrusted and needed to be removed beforepainting.
   这钢材生锈了，需要在上漆前除去。
2. 2. Thecar's engine needsrust removal before it can berepainted.
   这辆车的引擎需要除锈才能重新上漆。
3. 3. Theold iron gate needs rust removal before beingrestored.
   那把旧铁门需要除锈才能恢复原貌。