MetallurgistMember of ASTM, Naval Weapons Center, Materials Engineering Branch, China Lake, Calif.
An investigation was conducted to assess the relative merits of five soft magnet materials proposed as alternatives to ARMCO Electromagnet Iron (EMI), which is no longer available. Four irons and an SAE J403 (1005) (Unified Numbering System [UNS] G10050) steel were considered. When annealed in 94% nitrogen-6% hydrogen at 843°C (1550°F) for 4 h and aged at 100°C (212°F) for 400 h, two of the irons were found to be equivalent to EMI with regard to both coercive force and magnetic stability. A third iron exhibited similar magnetic properties after annealing but required a higher annealing temperature to reduce the coercive force to an acceptable value. The fourth iron and the 1005 steel met the coercive force requirement after annealing at 843°C (1550°F) in 94% nitrogen-6% hydrogen, but suffered significant increases in coercive force during aging at 100°C (212°F).
Paper ID: JTE11238J