Answer:
Laser Welding
Explanation:
Step 1: Let us first define what Heat-Affected-Zone (HAZ) is
According to https://www.twi-global.com, the heat affected zone (HAZ) is a non-melted area of metal that has undergone changes in material properties as a result of being exposed to high temperatures. These changes in material property are usually as a result of welding or high-heat cutting. The HAZ is the area between the weld or cut and the base (unaffected), parent metal.
Step 2: Which welding process produces the smallest HAZ?
According to https://www.weiss-aug.com, Laser welding may still use filler material, but it results in a very small heat affected zone, and may need a lot less in terms of follow-up processes than products welded through traditional methods.
Answer: Laser Welding
