A wide range of commercial heat-resistant alloys has been tested in a H2 + 10 % HCI environment at 550°C, 650°C, 680°C, 750°C, and 850°C. The tests were carried out using a 24 h cycle with a total test time of up to 1056 h. Weight change was determined, and the average value for three specimens per alloy and temperature plotted versus time, followed by a metallographic examination of the depth of corrosion. By a statistical evaluation of the data generated, it was possible to describe the weight change and penetration depth of all the alloys under examination as a function of the concentration of their main alloying elements and test temperature. According to these results, alloying elements nickel and molybdenum have a beneficial influence on chlorination resistance, whereas silicon and titanium are detrimental. Increased temperature always resulted in enhanced corrosion. Only Ni, Ni-Mo, and NI-Cr-Mo alloys show acceptable resistance for temperatures up to 850°C.
Keywords: Chlorination, Ni-base alloys, Fe-Base alloys, statistical evaluation, Mathematical description, Factorial analysis.