Sensitization Behaviour of Manganese-Alloyed Austenitic Stainless Steels

摘要

Manganese is an essential alloying element in advanced austenitic stainless steels with specific properties such as high resistance to harsh corrosive environments, high strength or low material costs. These materials are often used for welded constructions which have to be highly corrosion resistant. Hence it has to be ensured that the heat input during welding does not initiate the precipitation of chromium carbide resulting in a susceptibility to intergranular corrosion. This leads to the question whether the sensitization behaviour of manganese-alloyed austenitic stainless steels is comparable to that of the well-known conventional chromium nickel austenites. In the present work the effect of heat-input on the susceptibility of the CrNi-steel 1.4301 and the CrNiMn-steel 1.4376 to intergranular corrosion (IGC) was considered. Investigations were carried out by corrosion testing in the so-called Strauss-Test to elucidate the effect of the annealing temperatures on the microstructure. Furthermore, the influence of heat treatment on the mechanical properties was evaluated by tensile testing. As a result, it could be demonstrated that manganese-alloyed austenitic stainless steels like grade 1.4376 exhibit a sensitization behaviour very similar to the conventional austenitic steel grades. The same kinds of tests on intergranular corrosion resistance can be applied for both types of materials.