Magnetic domain imaging and mechanical/magnetic property characterisation of a 2507 type duplex austenitic-ferritic stainless steel

The effects of small amounts of cold deformation on the mechanical properties (tensile, impact) of a high nitrogen austenitic-ferritic duplex stainless steel (SAF 2507) were studied with a view of achieving high strength levels. In parallel a study of the magnetic properties (maximum induction, coercivity, remanence, permeability) of the same steel was carried out, under a static magnetic field or under stress conditions, with a view of optimising the ''magnetic behaviour'' of the steel (permeability, coercivity and remanence at earth's magnetic field). The results show, that excellent values of yield strength can be achieved in the as received condition or after small amounts of strain to the steel, coupled with excellent toughness. Moreover the steel exhibits moderate ''magnetic behaviour'', despite the sizeable amounts (-50%) of ferromagnetic ferrite present in the microstructure. (orig.)