The Successive Hydrogen Concentration Control in Molten Steel by Direct Hydrogen Measuring System

摘要

Low hydrogen content in the steel is required to steels, such as special bar quality, crank-shaft, railway wheel, structural steel etc. By using the conventional hydrogen analyzer, quick response and necessary accuracy can not be obtained. Long time RH treatment was essential. Eventually, RH vessel life has been shorter. Therefore, "dynamic-dehydrogenation model" has been developed to attain both an optimum operation of RH-degasser and a security for dehydrogenation of hydrogen content after treatment. Follow-ings are features of the dynamic dehydrogenation model: 1) Prompt adjustment of dehydrogenation by using direct hydrogen measurement system. 2) Correspondence to hydrogen pick-up from added alloys. 3) The K_H depends on many factors, for example, RH conditions, chemical component and other characteristics. It is well known that Q depends on the RH operating conditions. 4) The K_H clearly shows that maintenance of the snorkel diameter is important to keep the enough dehydrogenate rate. Also K_H is decreased sharply in the low [H] region lower than 1 ppm. With this model, treatment time was reduced by 6 min and the hydrogen content was controlled within the accuracy of ±0.2 ppm.