High temperature steam lines in power plant piping systems are often supported by the use of pipe support stanchions welded to the steam pipe. The end of the pipe stanchion has a steel plate welded to it, which typically slides on rack steel. For vertical and guide supports, there could be considerable thermal movement in the lateral unrestrained directions, and could result in significant frictional loads. The associated frictional loads are given due consideration in piping local stress evaluations as well as in the design of pipe support structures. For some situations, it often becomes necessary to utilize a teflon-fluorogold type surface at the stanchion end plate in order to reduce the coefficient of friction and hence the frictional loads. The effectiveness of the teflon-fluorogold surface is dependent on the prevailing temperature at that surface. In situations where the stanchions on very high temperature steam lines are relatively short, the temperature at the teflon surface of the stanchion plate could be high due to heat transfer from the steam line into the stanchion. This high temperature at the bottom surface of the stanchion plate may interfere with sliding and may eventually lead to unanticipated problems such as sticking, increase in the coefficient of friction, or unpredictable frictional behavior. In this paper, finite element analysis approach is utilized to perform heat transfer analysis and to obtain steady state temperature distribution due to decay or attenuation from the steam line surface along the stanchion. The temperature prevailing at the bottom plate surface of the stanchion is also evaluated and guidelines are provided for practical application of the results.
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