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Arc heating in the tundish with a graphite electrode in comparison to a metallic plasma torch
Author(s) -
Neuschütz Dieter,
Stadler Peter,
Bebber Hans J.
Publication year - 1996
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199605522
Subject(s) - torch , graphite , metallurgy , plasma torch , tundish , electrode , materials science , carbon steel , tungsten , chemistry , composite material , plasma , analytical chemistry (journal) , continuous casting , corrosion , physics , chromatography , quantum mechanics , welding
Since 1991, BGH Edelstahl, Siegen, operated a 0.4 MW tundish heater equipped with a DC metal plasma torch containing a tungsten electrode. Due to cost considerations, the metal torch has recently been replaced by a 100 mm diameter hollow graphite electrode. After 6 months of operational experience first results are now available on graphite wear rates, carbon pickup and running costs as compared to the metal torch system. The average wear rate was 0.46 kg/h or 0.03 kg/t steel. Carbon pickup under normal conditions was below 10 ppm for all steel grades investigated ranging from 0.015 to 0.455% C. The case of accidental direct contact between melt and graphite has also been investigated. The normal carbon pickup to be expected can be correlated to the tip wear rate of the graphite electrodes. From this correlation, carbon pickup would increase with power from 3 over 10 to 25 ppm for 0.3, 1 and 2 MW. The running costs proved to be lower than with metal torches due to less water cooling, less wear parts like nozzles and starting electrodes, and less personnel for maintenance.