The probabilistic properties of steel, namely, the mean value, coefficient of variation, and probability distribution are needed for the development of Load and Resistance Factor Design (LRFD) equations for Class 2 and 3 nuclear piping and for probabilistic and risk analysis studies. This work investigates the probabilistic properties for the most representative steels used for nuclear piping, such as carbon, stainless austenitic, and low alloy. Steel properties at room temperature and up to temperature 700 °F are examined through reported mechanical behavior. The work concludes with the impact of the stainless steels' probabilistic properties on the reliability index or else probability of failure for the piping. The presented data can help organize steel materials for LRFD and reduce the variability of the reliability index.