Structure Modification by Low Superheat Casting of Steels with High Shear Rate at British Steel

摘要

Research has been conducted on techniques for the production of steel grades at reduced superheat whilst maintaining high shear rates. Experiments have been carried out on the pilot plant scale for a range of carbon and stainless steels, and on the production scale for plate grade and high carbon grades. A generally finer and more equiaxed 'as cast' structure, as anticipated, is produced with reduction of centreline segregation, however, as superheat becomes progressively lower, off-centre, 'V' type segregation increases. For high carbon material, investigation of the regions of greatest segregation suggests an optimum superheat for casting, which prompted a shift from the initial aims of liquidus and sub-liquidus casting towards casting at low optimised superheats. Development of heat exchangers and trials results are discussed.