Sword of Goujian: The Sword That DEFIED Time.

Bronze doesn't rust lol it may oxidize

There are quite a few incorrect info here:
1) Guojian was not an emperor. He was a king of the Yue kingdom during the Warring States period.
2) This sword doesn't rust because it only contains small amounts of iron. It is mostly bronze, which oxidizes green but doesn't rust. It contains sulfur, which decreases tarnish.

Many swords and weapons and armor are still there in India which are ancient and still no rust in them and weight over 50kg spears are like 80kg.

Must be the woolz steel technology of ancient India transported to china by Buddhist monks.