In Laser Welding, or of the most basic pre-requisite is zero gap condition. I.e there must be absolutely zero gap between the two surfaces to be welded.
Hardening is one of the oldest metallurgical processes known to mankind, originally, in the form of heating the sword and then dipping it in water to achieve hardness.
In 1960, when Laser was first invented, it was regarded as a device looking for applications. Today, in the 21st century, it is difficult to find any field where laser cannot be used.
Laser is a modern advanced technology and it provides very powerful tools in a wide range of applications like manufacturing industries, mining , automotive, etc.