Discharge of molten steel

The simple tank discharge problem of Sec. 1.2.3.1 has been extended by Szekely and Themelis (1971) to cover the discharge of molten steel from a ladle into a vacuum degassing chamber the transfer being effected via a discharge nozzle, in which the effects of both friction and wear can be important. 

The effluent from the reaction boiler is handled in type 310 (UNS S31000) SS above 800° F (425° C), type 321 or 347 (UNS S34700) SS above 500°F (260°C), and carbon steel below 500°F (260°C). Molten sulfur is handled in steam-traced steel or aluminum. At the discharge to the pits, oxygen causes severe attack on steel, so the discharge end of the steel line often contains a short piece of alloy 20. 

Not only is there a need for the characterization of raw bulk materials but also the requirement for process controled industrial production introduced new demands. This was particularly the case in the metals industry, where production of steel became dependent on the speed with which the composition of the molten steel during converter processes could be controlled. After World War 11 this task was efficiently dealt with by atomic spectrometry, where the development and knowledge gained about suitable electrical discharges for this task fostered the growth of atomic spectrometry. Indeed, arcs and sparks were soon shown to be of use for analyte ablation and excitation of solid materials. The arc thus became a standard tool for the semi-quantitative analysis of powdered samples whereas spark emission spectrometry became a decisive technique for the direct analysis of metal samples. Other reduced pressure discharges, as known from atomic physics, had been shown to be powerful radiation sources and the same developments could be observed as reliable laser sources become available. Both were found to offer special advantages particularly for materials characterization. 

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