Motor generator set
Engine generator set
AC arc welding machine
AC welding transformer with a rectifier
Brass
Cast iron
Mild steel
High carbon steel
Rolling
Sliding
Dragging
Use a trolly
Cooling the metal
Heating the metal slowly
Hold at a given temperature
Heat and cool the metal as soon as possible
To increase softness
To with stand wear resistance
To withstand heavy load
To decrease the brittleness