SUN Li-yuan
,
LI Jing-she
,
ZHANG Li-feng
,
YANG Shu-feng
,
CHEN Yong-feng
钢铁研究学报(英文版)
To replace nickel-based stainless steel, a nitrogen-bearing stainless steel was produced to lower the production cost stemming from the shortage of nickel recourses. Thermodynamic model to calculate the saturated nitrogen content in the stainless steel was developed and the model was validated by experimental measurements performed with a high temperature induction furnace. Nitrogen gas under constant pressure was injected into the molten steel with a top lance. Thus, the nitrogen was transferred to the molten stainless steel. The effects of chemical composition, temperature, superficial active elements and nitrogen flow rate on the transfer of nitrogen to the steel were investigated and discussed. The results showed that the dissolution rate of nitrogen in the molten steel increases with a higher temperature and larger nitrogen flow rate but decreases significantly with an increase in the content of surface-active elements. Alloying elements such as chromium and manganese having a negative interaction coefficient can increase the dissolution of nitrogen in the molten steel. It was also proposed that the primary factor affecting the final saturated nitrogen content is temperature rather than the dissolved oxygen content.
关键词:
nitrogen-bearing stainless steel
,
nitrogen
,
thermodynamic modeling
FU Jian-xun
,
LI Jing-she
钢铁研究学报(英文版)
The broadening of slab was investigated on the basis of several industrial manufactures of continuous casting. The results show that slab broadening commonly exists in the process of continuous casting. It is found that there are few reports on it until now. In order to find out the reasons of slab broadening, we checked the effect of change of mold size, excepting technological parameters, conditions of soft reduction, and contraction of roll gap on slab broadening. Our examinations exclude the possibility of change of mold size, excepting technological parameters to be the causes of broadening of slab. The broadening of slab probably results from the static pressure of molten steel and the force from driving rolls. At the same time, online observations on three kinds of steel in the process of continuous casting reveal that the average objective ratio of slab broadening ranges from 1.27 % to 3.00 %, and even arrives at 4.4 %. In addition, the width of mold and formulas of calculating the broadening of slab was deduced.
关键词:
continuous casting;slab;broadening;industrial investigation
