Low superheat casting
The project took previous knowledge about improving the quality of products in slab casting and applied it to the production of heavy plates. The use of a very low superheat level in the mould has been found to improve internal soundness and homogeneity of the steel when casting slabs. An innovative heat exchanger, the submerged 'Hollow Jet Nozzle' (HJN), was developed by CRM to allow casting with a low superheat in the mould without varying the temperature level in the tundish. The design, building and testing of an HJN exchanger suited to casting with a high steel flow rate was the first phase of the project, followed by the integration of the new casting technique into industrial slab casters. Trials with industrial casters of both slabs and plates, with various steel output rates and various grades of steel, were carried out. The results showed the effectiveness of the HJN in achieving the reduction in temperature between the tundish and the slab moulds, and the products showed the desired high quality in terms of the high proportion of equiaxed structure and reduced centreline segregation. No improvement was seen in the mechanical properties of heavy plates (80mm) cast with a low superheat, perhaps because of the effects of the hot rolling process. Moreover, for the X65 steel grade, a loss of cleanliness was observed, and there was an increase in hydrogen-induced cracking, when mould superheats below 15ºC were used.
Bibliographic Reference: EUR 18614 FR (1998)
Availability: Available from OOPEC Sales agents
Record Number: 199910506 / Last updated on: 1999-03-26
Original language: fr
Available languages: fr,en