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Title: Closed loop control of the induction heating process using miniature magnetic sensors

Abstract

A method and system for providing real-time, closed-loop control of the induction hardening process. A miniature magnetic sensor located near the outer surface of the workpiece measures changes in the surface magnetic field caused by changes in the magnetic properties of the workpiece as it heats up during induction heating (or cools down during quenching). A passive miniature magnetic sensor detects a distinct magnetic spike that appears when the saturation field, B.sub.sat, of the workpiece has been exceeded. This distinct magnetic spike disappears when the workpiece's surface temperature exceeds its Curie temperature, due to the sudden decrease in its magnetic permeability. Alternatively, an active magnetic sensor can measure changes in the resonance response of the monitor coil when the excitation coil is linearly swept over 0-10 MHz, due to changes in the magnetic permeability and electrical resistivity of the workpiece as its temperature increases (or decreases).

Inventors:
; ;
Issue Date:
Research Org.:
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1174338
Patent Number(s):
6566636
Application Number:
10/207,424
Assignee:
Sandia Corporation (Albuquerque, NM)
Patent Classifications (CPCs):
G - PHYSICS G05 - CONTROLLING G05D - SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
H - ELECTRICITY H05 - ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR H05B - ELECTRIC HEATING
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY

Citation Formats

Bentley, Anthony E., Kelley, John Bruce, and Zutavern, Fred J. Closed loop control of the induction heating process using miniature magnetic sensors. United States: N. p., 2003. Web.
Bentley, Anthony E., Kelley, John Bruce, & Zutavern, Fred J. Closed loop control of the induction heating process using miniature magnetic sensors. United States.
Bentley, Anthony E., Kelley, John Bruce, and Zutavern, Fred J. Tue . "Closed loop control of the induction heating process using miniature magnetic sensors". United States. https://www.osti.gov/servlets/purl/1174338.
@article{osti_1174338,
title = {Closed loop control of the induction heating process using miniature magnetic sensors},
author = {Bentley, Anthony E. and Kelley, John Bruce and Zutavern, Fred J.},
abstractNote = {A method and system for providing real-time, closed-loop control of the induction hardening process. A miniature magnetic sensor located near the outer surface of the workpiece measures changes in the surface magnetic field caused by changes in the magnetic properties of the workpiece as it heats up during induction heating (or cools down during quenching). A passive miniature magnetic sensor detects a distinct magnetic spike that appears when the saturation field, B.sub.sat, of the workpiece has been exceeded. This distinct magnetic spike disappears when the workpiece's surface temperature exceeds its Curie temperature, due to the sudden decrease in its magnetic permeability. Alternatively, an active magnetic sensor can measure changes in the resonance response of the monitor coil when the excitation coil is linearly swept over 0-10 MHz, due to changes in the magnetic permeability and electrical resistivity of the workpiece as its temperature increases (or decreases).},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2003},
month = {5}
}

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