Converter Smelting Process And Properties Of 40Cr Steel Containing Rare Earth Element

At present,alloy structural steel enterprises generally use electric furnace smelting process as the main production equipment of alloy structural steel.However,Chinese electric furnace smelting technology is poor with high cost of power consumption.whilethe long term of alloy structural steel scrap cycle and the small scrap supply restricted the development of the electric furnace smelting alloy steel structure and steeltechnology.This paper focuses on the status quo of our country,focusing on the alternative process of electric furnace smelting process.In order to carry out the alloy structure steel smelting production,we choose the general smelting process of plain carbon steel.Focusing on the yield index of chromium element in alloy structural steel production process,we select the general smelting process of dephosphorization of pig iron in blast furnace--the smelting process of oxygen blowing in converter--external refining--continuous casting.We alsoadopt pure molten iron as raw material instead of scrap.Through the change in smelting process of furnace temperature,oxygen supply intensity and oxygen lance position,we reduce the gas content in terminal steel and adjust the components of molten steel.Through Dephosphorizing pig iron berfore getting into the furnace,we adopt the refinemet procedure to purify the liquid steel to ensure the end point steel to achieve the quality of molten steel in electric arc furnace.Adding lanthanon in refinement,with the basic heat treatment method,we analyze the property ofquenching and tempering and findings are as follows:(a)Researching the oxidation characteristics of Si-Cr,we may add the saturated silicon element4)2 to reduce the oxidation of chromium.(b)In the process of BOF alloy structural steel smelting,we may adjust oxygen pressure to reduce PCO in molten bath as well as increase the temperature in molten bath to decarburize and to keep chromium.(c)Add lanthanon to smelt 40 Cr alloy structural steel,under the circumstance of water quenching800?�15min and tempering550?�90min,it shows excellent mechanical properties.(d)With high phosphorus hot metal and converter oxidation process,the problem of pour slag,adjusting slag and dephosphorization can be effectively relieved in the process ofelectric furnace,which improves the smelting efficiency and reduce the problem of phosphorus enrichment during the whole process of scrap.(e)The adding of ianthanon greatly reduced the crack which caused by the non metallic inclusion based on Mn elements during rolling process.The adverse effect appeared in the use of finished product that is the fatigue pointinfluece the material quality performance.