No serious galvanic action will occur by combining the same metals only dissimilar ones. The metals listed at the top of the table below will corrode first due to galvanic reaction before those at bottom of the table. Stands for Military Standards. The overriding characteristic of MS fittings compared to commercial products is the extensive inspection and lot traceability for MS, guaranteeing the chemical, physical and dimensional qualities. While commercial fittings may look similar and happen to pass many tests given MS products, the commercial fittings lack the pedigree of guaranteed quality or chemical, physical and dimensional aspects that users who order MS fittings rely on.
Test simply determines the level of magnetism.
This term differs depending on the application. Fittings and hardware are usually made of Type 316 stainless to resist corrosion. They are usually highly polished. Nicknamed moly, molybdenum is a metal added to 316 stainless steel, sharply increasing its corrosion resistance to chlorides and sulfates especially various sulfurous acids in the pulp industry. Molybdenum helps reduce hardness and increase tensile strength at higher temperatures.