Garrett Barnes This is an excellent question that touches on a number of interesting and competing effects. In the video we refer to one of the principal driving forces as simply “adhesion”. In actuality this is more of an adhesion balance. We have competing effects of base to base metal adhesion, oxide layer adhesion, and oxide layer self-adhesion. By employing dissimilar metals, we can accomplish multiple outcomes including increasing oxide-to-oxide adhesion in comparison to oxide-base adhesion and reducing base-base adhesion. Combining that with the aforementioned hardness disparity and we can limit the propensity for galling.

The future is now! You've described cold welding: kzfaq.info/get/bejne/Y62DdLaJ3dfUnaM.html

BlackHawkEP Amazing! Too bad it needs high pressures to work. It would be great if you could put two pieces against each other and they just grew together. It would probably demand extremely high precision on the surface quality so that the atom structures comes really really close together. PS: Thanks for all the replies =)

There is already a group of welding processes called "Friction Welding". It is practically what you had described.

You're right - we're experts at bolted joint integrity; we need to up our audio mixing game! Thanks for the feedback.

Exactly the same here! Great presentation, hated the music - not needed at all.