PROCESS FOR HEAT TREATING A HEAT EXCHANGER TUBE SURROUNDED BY A SUPPORT PLATE

摘要

A process for rapidly and uniformly heat treating an Inconel* heat exchanger tube in the vicinity of a heat sink such as a support plate is disclosed herein. The process utilizes a radiant heater assembly capable of directing heat along a zone whose length is less than the length of the section of tubing to be stress relieved, and generally comprises the step of actuating the heater assembly, and oscillating it between the ends of the tube section in order to heat the tube section having nonhomogeneous thermal conductivity to a temperature that is substantially uniform along its length. The specific timing pattern used in the oscillatory movement of the heater assembly results in a substantially uniform heat gradient along the tube axis despite conductive heat losses through the support plate. The process allows heat exchanger tubes to be readily and reliably stress-relieved in the vicinity of the support plates of a nuclear steam generator.