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DUPLEX PROCESS OF 2.5% Si-Fe MATERIAL FOR MAGNETIC APPLICATION REQUIRING SURFACE ANNEALING

IP.com Disclosure Number: IPCOM000046691D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Verma, DK: AUTHOR

Abstract

Printhead armatures made of 2.5% Si-Fe material have inherently superior magnetic response than those made from electrical iron. The 2.5% Si-Fe material has a lower coercive force, and this results in a faster cycling time of the printhead armatures and thus the print wires. The armatures, however, require a wear resistant surface. This is achieved by providing a hardened case using carbon and nitrogen diffusion and subsequent martensitic transformation. Prior to case hardening, the armatures require annealing to relieve the cold work and thereby increase the coercive force levels.

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DUPLEX PROCESS OF 2.5% Si-Fe MATERIAL FOR MAGNETIC APPLICATION REQUIRING SURFACE ANNEALING

Printhead armatures made of 2.5% Si-Fe material have inherently superior magnetic response than those made from electrical iron. The 2.5% Si-Fe material has a lower coercive force, and this results in a faster cycling time of the printhead armatures and thus the print wires. The armatures, however, require a wear resistant surface. This is achieved by providing a hardened case using carbon and nitrogen diffusion and subsequent martensitic transformation. Prior to case hardening, the armatures require annealing to relieve the cold work and thereby increase the coercive force levels. If the raw stock for the armatures is produced by a process such as vacuum arc remelting to provide clean material, the required annealing time is reduced from approximately three hours to approximately one hour and the temperature is reduced from approximately 1700OEF to approximately 1500OEF. The gas carbonitriding process for producing the hardened case is normally done at approximately 1500OEF with a cycle time of about one hour to achieve a case depth of approximately 0.003 inch. Thus, with the clean material, the two separate steps of annealing and gas carbonitriding can be combined in one single operation because of the compatible time and temperature levels. The result of this duplex processing is a hardened case and an annealed core. The coercive force level is approximately the same or...