Question

even iron get rusted,we are using for building constructions as a traditional metal.is it correct if not suggest alternate metals

Answer 1

Steel has been a major component of construction since the late 1800. Before that, builders use iron which gets rusted with the passage of time. So, ever since, steel has not only become the best building material but also contributes in the economical wealth. 
Nowadays, alternate metal alloys and composite materials are gaining more popularity in both domestic and commercial construction. They are more durable then steel and require less heavy machinery. The only drawback is that they are costly as compared to steel as they are relatively new in the market.