Secondary Refining for Steel and Pretreatment for Hot Metal（Bilingual Language）主讲讲教师师：成国光 王灿灿国Teaching Schedule(27 teaching hours)Three parts：First Part ：Content with “Secondary Refining for Steel”， 14 teaching hours.Second Part ： Content with ”Pretreatment for Hot Metal”， 10 teaching hours.Third Part：students-selves study and fininshing course examination paper,3 teaching hours. 1Part 1 Secondary Refining of Steel1、Introduction (2 hr. ) 1.1Bachground,task,future development for secondary refining 1.2 Brief introduction to main teaching contents 2、Fundmental principles for steel refining (2 hr. ) 2.1 Deoxidation, Desulphurization 2.2 Decarburization 3、 Fundmental principles for steel refining (2 hr. ) 3.1 Degassing 3.2 Inclusions Removal 4、Typical apparatus for secondary refining (2 hr. ) 4.1 LF 4.2 RH 5、 Typical apparatus for secondary refining (2 hr. ) 5.1 VOD 5.2 AOD 6、Refining process for high quality steel (2 hr. ) The process for ultra-low oxygen special steelmaking for high quality automobile parts 7、 Refining process for high quality steel (2 hr. )The process for ultra-low carbon steel refining for IF automobile sheet2Part 2 Pretreatment of Hot Metal1、Introduction (2 hr. ) 1.1Bachground,task,future development for hot metal pretreatment 1.2 Brief introduction to main learning contents 2、Fundamentals for desulphurization (2 hr. ) 2.1 Basic principles 2.2 desulphurization process 3、 Fundmentals for desiliconization (2 hr. ) 3.1 Basic principles 3.2 desiliconization process 4、 Fundmentals dephoursphrization (2 hr. ) 4.1 Basic principles 4.2 dephoursphrization process 5、 Typical integrated “three Des” process for hot metal (2 hr. )Brief introduction combined with one advanced example. 3The possible gains to be expected for those students who listen to and are interested in this bilingual course: (1)To understand the fundamentals of secondary refining for high quality steels.(2)To understand the processes and operations concerned with clean steel .(3)To learn some new making processes and technology for improvement of steel quality. 41.Introduction-Requiremens for High quality SteelIn order to satisfy the requirements placed by consumers on the material “steel” ,steelmakers who wish to produce steel competitively for the market of today,must come up with acceptable prices and also guarantee highest quality.5BF (Blast Furnace)BOFEAFSCRAPCastingSteel RefiningPretreatment ofHot MetalPresent Steelmaking Process System6As a result, EAF(Electric Arc Furnace) is being forced to an increasing degree into the role of pure melting and a lot of metallurgical works are carried out in downstream units. BOF (Blowing-Oxygen- Furnace) is also only used to decarburizaion unit.7The increasing use of continuous casting units with strict quality requirements and short sequence casting times also calls for appropriate secondary steelmaking installations.8Every steelworker should be familiar with the fundamental metallurgical principles of ladle treatment.These principles form the basis for selecting suitable secondary steelmaking facilities to be used.The integration of ladle treatment installations between melting and casting units as well as the choice of appropriate plant concepts and equipment are part of the primary engineering activities of plant constructors.9Secondary steelmaking installations such as ladle furnaces(LF), vacuum tank degassers(VD), vacuum circulation degassers (RH) have proved to be successful and are today an indispensable components in the planning of new steelworks or modernization of existing facilities.AOD and VOD are still keeping the leading position as refining means in stainless making. LFVDRH10VOD AOD112、Fundmental principles for steel refining 2.1 Deoxidation, Desulphurization2.1.1 Deoxidation 2.1.2 Desulphurization2.2 Decarburization122.1.1 Deoxidation(1) Si,Al-Killed reactionAdvantages: reaction very quickly Disadvanges: deoxidation resultants such as SiO2 , Al2O3 etc. still remaining in steel bath,which have to be removed in following process.13The factors related to deoxidation reaction efficiency:uInitial oxygen content in steel ;uKinds of deoxidant；uReaction temperature；uK.14(2) Vacuum Carbon Deoxidation(VCD)C+O=COK=PCO/(%C%O)%O=PCO/(%CK)Advantages: no deoxidation resultant remaining in steel bathDisadvanges: vacuum is indispensable15The factors related to VCD deoxidation reaction efficiency:uPressure in vacuum chamber ；u Initial oxygen content in steel ;uStirring；uReaction lasting time.162Al + 3O = (Al2O3)(3) Covering Slag Deoxidation17The effect of slag composition on oxgyen content in steelAl-killed18Si deoxidation：Si + 2O = (SiO2)1920(4).Steel Deoxidation Example21Bad quality found in final productsCracks occurred during fanmakingCracks formed in pipe drawing22Bad bending specimen23Sketch map of slag- steel reaction in ladleOSi SiPSFeO大气SiO2SiO224(FeO)OSlag bas