Tungsten is a very dense and robust metal that has the highest melting point and boiling point of any metal. This makes it very resilient in certain situations but also makes it hard to craft stuff with in a forge.
Let's say that in 1300 AD, every kingdom gains access to a magic wand. This wand can turn a steel weapon or steel armor into pure single-crystalline tungsten. The tungsten will be in the same shape as the steel was in. Will tungsten weapons and armors prove superior to steel ones now that production isn't an issue?