Friction welding

Third one was induction heating, not friction welding, and last one was the shittiest friction "welding" possible

I hadn't seen glass fused using this method before

The legos will just stick together, you don’t have to weld them

The third one was induction welding; not friction welding.

Although the object was rotating, this method is electrical induction heating, not friction.

Isn’t the third one just quenching? Not sure how it’s friction welding.

Linear friction welding joins two parts by pressing them together while one moves rapidly back and forth

Helps to preheat the two parts. The one before the Lego was induction heating.

Note: Friction welding joins metals by heating them through friction. One part spins while pressing against a stationary part, generating heat until the metals bond. This process is fast, energy-efficient, and creates strong, clean welds. It's ideal for dissimilar metals and materials like steel, aluminum, and titanium, commonly used in automotive, aerospace, and manufacturing industries.

That's an induction heater