You might think, welding a ship together: what could possibly go wrong?
The first ships that were welded would suddenly break in two. These were the liberty ships used in WW2: https://en.wikipedia.org/wiki/Liberty_ship
The first ships that were welded would suddenly break in two. These were the liberty ships used in WW2: https://en.wikipedia.org/wiki/Liberty_ship
These incidents are what led to the creation of the field of materials science.
(Wikipedia link above.)