Strengthen, in metallurgy (6)

I believe the answer is:

anneal

(Other definitions for anneal that I've seen before include "Heat treat (metal/glass)" , "Soften or toughen" , "Make tough" , "Toughen using heat" , "Harden by heating and cooling" .)

I've seen this clue in the LA Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.