ISAMELT technology is a relatively new commercially available approach which launched in 2009 and is based on furnace design which was derived and developed from the first ever demonstration level furnace in 1983 in Australia.
Advantages include lower emissions, highly efficient mixing through lance injection, and small plant footprint through vertical process approach.
Semi-austenitic stainless steels are just one of three groups of materials which are precipitation hardened steels, the others being martensitic and austenitic.
Some key characteristics of semi-austenitic stainless steels are high strengths, as well as high toughness, and corrosion resistance along with less favorable traits such as low fracture toughness in high strength conditions and low (subzero) temperatures.
The main objectives of grain refinement is to achieve a fine, uniform and equiaxed grain structure which in turn will lead to a much improved, stable and predictable set of mechanical properties.
There are several process techniques for achieving refinement including rapid cooling, melt super heating, alloying addition of Zr and carbon inoculation as well as mechanical methods such as vibration and agitation.
Non-metallic inclusions are an ever present issue which adversely affects mechanical properties and therefore overall material performance.
As we know, the presence of Sulphur can significantly improve the machinability of steel but deformable MnS inclusions resulting from rolling and forging, can lead to anisotropy in mechanical and fatigue properties.