Magnetic Steel Chamfer Magnetic steel chamfer strip has been used in the precast concrete industry for several decades. They can handle extreme working conditions and are used to attach steel surfaces. They were designed to create beveled edges on the corners of concrete wall panels as well as some formwork. There are two commonly used shapes: triangle and trapezoid. Magnetic strips for precast concrete are one of the most versatile accessories used in the precast concrete industry. They come in several different sizes and can be fully customized to suit a manufacturer’s specific requirements.