Which formula represents longitudinal magnetization?

The formula that represents longitudinal magnetization is based on the recognized relationship between magnetizing force and the length and diameter of the test piece. In magnetic particle inspection, the primary goal is to apply an appropriate magnetizing force to reveal indications of surface or near-surface defects by using magnetic particles.

For longitudinal magnetization, the formula you have chosen—Ampere-turns = 45,000/L/D—accurately reflects the balance necessary to achieve the required magnetic field for this technique. The specification of 45,000 as a factor in the formula indicates a specific multiplication factor for the ampere-turns necessary to establish the magnetic field along the length of the test piece, adjusted for its diameter.

This formula considers the physical dimensions of the part being tested, where L represents the length and D represents the diameter, ensuring proper magnetization is achieved given the size of the component. As a result, regardless of the material or size, using this formula will help technicians to effectively identify defects through controlled magnetization.

By understanding the need for the longitudinal magnetization and the specific value of 45,000, one can effectively set up a magnetic particle inspection procedure for components requiring this specific type of evaluation.