HIGH STRENGTH STAINLESS STEEL HAVING A HIGH RESISTANCE TO CORRO SIVE AND ABRASIVE WEAR IN CORROSIVE ENVIRONMENTS PARTICULARLY CHLORIDE ENVIRONMENTS

摘要

1456634 Stainless steel compositions LANGLEY ALLOYS Ltd 13 Dec 1973 [13 Sept 1972] 42534/72 Addition to 1158614 Heading C7A A stainless steel alloy as defined in Specification No. 1158614 and consisting, by weight, of:- the balance being iron, is provided with a microstructure having 40 to 60% austenitic grains in a ferrite matrix and a corrosion resistance measured by a potentiostatic test such that when held at a potential of 600 mv. in a 3% solution of NaCI at 30‹C for 10 minutes, the current flow does not exceed 100 microamps per sq. centimetre, these properties being conferred by solution heattreatment at 1050 to 1150‹C. An optional hotworking may be incorporated, e.g. rolling forging or extrusion. The solution heat-treated product may be aged at 480 to 550‹C for 2 to 6 hours. The products are particularly suited to materials in marine or chemically corrosive environments, e.g. marine propellers and shafts, valves, pumps or pies and valves in chemical apparatus; the invention is also applicable to the scrubber tanks of marine tankers.