Magnetic-particle inspection is a method of locating surface and subsurface discontinuities in ferromagnetic materials. This article discusses the applications and advantages and limitations of magnetic-particle inspection. It describes magnetic fields in terms of magnetized ring, magnetized bar, circular magnetization, longitudinal magnetization, and effects of flux direction. General applications, advantages, and limitations of the various magnetizing methods used in magnetic-particle inspection are listed in a table. The article discusses the items that must be considered in establishing a set of procedures for the magnetic-particle inspection of a specific part: type of current, type of magnetic particles, method of magnetization, direction of magnetization, magnitude of applied current, and equipment. It concludes with a discussion on demagnetization after magnetic-particle inspection.

This article focuses on nondestructive inspection of steel bars. The primary objective in the nondestructive inspection of steel bars and wire is to detect conditions in the material that may be detrimental to the satisfactory end use of the product. The article discusses various types of flaws encountered in the inspection of steel bars, including porosity, inclusions, scabs, cracks, seams, and laps. Inspection methods, such as magnetic-particle inspection. liquid penetrant inspection, ultrasonic inspection, and electromagnetic inspection, of steel bars are also described. The article provides a discussion on electromagnetic systems, eddy-current systems, and magnetic permeability systems for detection of flaws on steel bars. It concludes with a description of nondestructive inspection of steel billets.

Magnetic-particle inspection is a nondestructive testing technique used to locate surface and subsurface discontinuities in ferromagnetic materials. Beginning with an overview of the applications, advantages, and limitations of magnetic-particle inspection, this article provides a detailed account of the portable power sources available for magnetization, and the different ways of generating magnetic fields using yokes, coils, central conductors, prod contacts, direct-contact, and induced current. In addition, the article discusses the characteristics and classification, and properties of magnetic particles and suspended liquids. Finally, the article outlines the types of discontinuities (surface and subsurface) that can be identified by magnetic-particle inspection and the importance of demagnetization after inspection.

The most popular metal hot working processes for which induction heating is applied are forging, forming, extrusion, and rolling. This article focuses on estimation techniques to determine basic induction heating process parameters, including coil power, length of heating line, and frequency selection. It discusses three modes of heat transfer: conduction, convection, and radiation, in induction heating. The article describes the factors affected by a distortion of the magnetic field at the coil end through a schematic illustration of distribution of three magnetic force components experienced by the turns of the coil. It concludes with information on some case studies of numerical simulation.

Induction heating has the ability to concentrate the electromagnetic field and heat within a certain area of the workpiece. This article provides a detailed discussion on the end heating of bars, rods, and billets using solenoid inductors, oval inductors, and channel inductors. It reviews the importance of computer modeling in predicting the impact of different, interrelated, and nonlinear factors on the transitional and final thermal conditions of billets and bars. The article describes the most appropriate processes to improve end heating process effectiveness. Induction bending of narrow circumferential band of pipe or tube is also discussed. The article concludes with a discussion on stress relieving of pipe ends and welded areas.

This article provides a rough estimate of the basic parameters, including coil efficiency, power, and frequency in induction heating of billets, rods, and bars. It focuses on the frequency selection for heating solid cylinders made of nonmagnetic metals, frequency selection when heating solid cylinders made from nonmagnetic alloys, and frequency selection when heating solid cylinders made from magnetic alloys. The article describes several design concepts that can be used for induction billet heating, namely, static heating and progressive/continuous heating. It presents the four major factors associated with the location and magnitude of subsurface overheating: frequency, refractory, final temperature, and power distribution along the heating line. The article summarizes the pros and cons of using a single power supply. It also reviews the design features of modular systems, and concludes with information on the temperature profile modeling software.