CORROSION RESISTANCE OF ALLOY 31 AND 59 IN HIGHLY CORROSIVE DANGEROUS GOODS

摘要

Alloy 31 (UNS N08031, X1NiCrMoCu32-28-7) is a superaustenitic iron-nickel-chromium-molybdenum alloy with nitrogen addition filling the gap between existing stainless steels and nickel alloys. Alloy 59 (UNS N06059, NiCr23Mo16Al) with a high chromium, molybdenum and nickel content possesses excellent resistance not only to reducing but also to oxidizing chemicals.Both are already in use as shell materials for tank vehicles or tank containers. They allow the transport of quite more chemicals and especially waste mixtures than when using common austenitic steels. Another advantage is the reduction of required inspections of the transport tanks. In Germany the "BAM-List - Requirements for Tanks for the Transport of Dangerous Goods" is the basis for substance-related prototype approvals for tank containers designed for the carriage of dangerous goods undertaken by BAM, the Federal Institute for Materials Research and Testing. Compatibility evaluations of selected metallic material groups as well as of polymeric gasket and lining materials under the influence of approximately 7000 dangerous goods and water-polluting substances are published in the BAM-List.Due to the large number of dangerous goods in the BAM-List the established corrosion test program with welded specimens of these higher-alloyed materials is being continued. Various acid mixtures were added to the exposures of the two materials at 55 °C. Other corrosive test substances are different organic an inorganic halogenides, peroxyacetic acid, and molten substances. In case of molten chemicals and due to other practical reasons the test temperature is increased to more than 100 °C. The test results, presented in this paper, are already included in the current edition of the BAM-List and therefore available to the costumer.