This two-piece design also allows the screws and shafts to be replaced independently of one another, maximizing interchangeability while reducing maintenance cost and downtime. Shafts are made of high-quality stainless steel (DIN rating 1.4542, ANSI 630 S.S.) as standard equipment. The excellent physical properties and chemical resistance of this steel grade has been proven on thousands of Bornemann Pumps worldwide. The screws can be supplied in a wide range of materials including cast iron, nodular iron, bronze, and various stainless steel grades - allowing numerous different material combinations to best fit the particular application at hand. For the pump casing there are various materials available including cast iron, nodular iron, or cast steel.