Materials Larson-Miller Parameters

Tube wall temperature is an important parameter in the design and operation of steam reformers. The tubes are exposed to an extreme thermal environment. Creep of the tube material is inevitable, leading to failure of the tubes, which is exacerbated if the tube temperature is not adequately controlled. The effects of tube temperature on the strength of a tube are considered by use of the Larson-Miller parameter, P (Ridler and Twigg, 1996) ... 

C Material constant used in computing Larson-Miller parameter ... 

The creep rupture data are derived from laboratory tests on material samples having a standardized geometrical form. The convenient way to express these data is to plot the stress versus the Larson-Miller parameter P ... 

The Larson-Miller parameter, P, in Eq. (6.102), is one of the useful parameters used for predicting creep life in metallic materials, but it is useful for ceramics as well. The LMP may be used to describe the stress-temperature-life relation in a SiC/SiC composite by means of the following expression ... 

Engineering design often requires engineers to predict material properties at high temperatures where no experimental data are available. The creep deformation rate can be so slow that it might require 10 years test time to reach 1% deformation. Reliable predictions based on accelerated test data obtained over a shorter period of time are essential. Several theoretical parameters were proposed to predict long-term metal creep or stress rupture life based on short-term test data. One of the most utilized parameters is the Larson-Miller parameter, as defined by Equation 4.20 ... 

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