Steel Strip from rebrebarandsteel's blog

Steel strip is uncoiled and guided, cold, through units of forming rolls to supply the cylindrical form. At the purpose where the perimeters meet, a high frequency present is introduced into the edges of the strip, either by induction utilizing an encircling coil or by contacts sliding on the surface of the strip. The electric present produces sufficient native heat to melt the strip edges as they're cast collectively - diesel motors.