A Material Challenge – Pumps in Sulphuric Acid Application

Sulphuric acid is a highly corrosive liquid for metal alloys as well as for other materials. There are only a few metal alloys, which are recommended in the range of 0 – 99% H2SO4. Beside these corrosion problems there are additionally corrosion issues found in pumps caused by the high rotational speed and the turbulences depending on the point of operation. Deviations in process may lead to unexpected corrosion phenomena, too.An overview over materials as for example Duplex, higher austenitics as e.g. Alloy 20, ferritic alloys and high silicon alloys as SX and Siguss (ASTM A518) will be given. All these materials are classified for the optimal application in sulphuric acid service. Advantages and disadvantages of these materials in sulphuric acid are discussed. For example, the material Siguss shows the most universal corrosion resistance in sulphuric acid, especially for very hot and middle concentrated sulphuric acid.Some typical corrosion examples will be shown, too. An important kind of corrosion called erosion-corrosion is explained.