INTRADOS INDUCTION HEATING FOR TIGHT RADIUS ROTARY DRAW BEND

摘要

A boost bend method of making tight radius bends in boiler tubes, such as bends having a radius of lxD or less, in which a selected portion of the intrados of the tube is heated in a controlled manner thereby reducing the necessary tube wall thickness relative to the diameter of the tube for 180.degree. bends. Tubes bent using the method may have wall thicknesses of about 6.6% of the tube diameter and suffer less than about 7% thinning of the extrados tube wall.