The best flame for gas cutting is neutral flame (or micro-carbonized flame), not wind line! The wind line is a pure oxygen cutting wind line.

When adjusting the flame, first open the gas valve and a little oxygen valve before ignition, and then slowly increase the amount of oxygen after ignition. At this time, the flame in the blue area of the flame is slowly shortened from the outer flame to about 10~ 12mm outside the flame center, which is a neutral flame.

See the picture.