LIFETIME ESTIMATING METHOD FOR HEATER STRAND, HEAT TREATMENT APPARATUS, RECORDING MEDIUM, AND LIFETIME ESTIMATING PROCESS SYSTEM FOR HEATER STRAND

摘要

A method is provided to estimate the lifetime of a heater line as compared with a conventional technique by using data related to a time interval for which the heater line is easily disconnected when the lifetime of the heater line is estimated. The maximum value of power(134A-134E) supplied to a heater line(132A-132E) within a period for increasing the temperature up to a heat treatment temperature is detected. When the maximum value of the power is determined to exceed a previously determined critical value, an alarm process is performed to inform that the lifetime of the heater line comes to an end. The critical value can be predetermined according to the condition of the heat treatment.