active iron

例句：

1. 1.The steel is made from active iron, which makes it strong and durable.
   这种钢是由活性铁制成的，因此它既坚固又耐用。
2. 2.Active iron is a type of metal that undergoes a phase transformation when heated.
   活性铁是一种在加热时会发生相变类型的金属。
3. 3. In the manufacturing process, active iron is often used to create molds for casting parts.
   在制造过程中，活性铁常被用于制作铸造部件的模具。