韩国钢铁材料研究现状 Choo Wung Yong院士.pdf

HIPERS-21 POSLABPresent Developing Status of High Performance Steel in Korea(Hipers-21 Project)Choo, Wung YongTechnical Res. Labs.POSCOHIPERS-21 POSLAB100-200 Stories BuildingImprovement in Transportation Efficiency Safety Requirement and Easy Forming`Required Properties• High Strength• High Toughness• Easy Fabrication• Long Endurance Life• Good RecyclabilityIndustrial Circumstance of 21CLong Span Bridge and Maintenance FreeHIPERS-21 POSLABProperties of HIPERS-21 SteelHIPERS - 21High Strength Bolt Weathering Steel• Strength : 800MPa →1,500MPa• Delayed Fracture Resistance• tσ = 0.5TS ≥ 150hr• Maintenance-Free• Long Life : 50year → 100year• Seawater Corrosion Resistance800MPa Structural Steel• Strength : 400MPa → 800MPa• C-Mn Base Steel : Recyclability• No Heat Treatment• Low Ceq : Preheating-Freein Welding• DBTT ＜ -200 ℃HIPERS-21 POSLABDeveloping TargetHigh Strength Bolt● TS : 800 MPa → 1500 MPa● Improvement of DelayedFracture BehaviorWeathering Steel● Corrosion Resistance: Twice● Service Life Cycle: 50yr → 100yrStructural Steel● TS : 400 MPa → 800 MPa● Elimination of PreheatingWelding● Oxide metallurgy● Development of Welding WireDesign & Construction● Development of New Design Concept● Evaluation of JointPropertiesFabrication● New Concept Welding Technology● Analysis of Structural StabilityOxide Metallurgy● Dispersion & Precipitationof Fine Particles● Ultra Clean Steel● Enhanced Safety● Long Life cycle● EconomicalConstruction● Maintenance-freeSteel StructureHIPERS-21 POSLAB● Basic Research for Ultra Fine-Grained Steel (1㎛ ) Multi-axis Deform E-cap Groove rolling● Commercial Production ● Design & Development of Pilot Scale New Facility for Ultra Fine-Grained Steel● Application of Ultra Fine-Grain to Large Steel Structure 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007First Stage Second StageMile stone 600 mpa grade fine grained steel 500 Mpa grade seawater resistance steel13 1300 Mpa grade high strength bolt steel● Commercial Production  800 mpa grade fine grained steel 600 Mpa grade seawater resistance steel 1500 Mpa grade high strength bolt steelHIPERS-21 POSLABStructural Steels Tensile Strength : 400 MPa → 800 MPaBreakthrough : Grain Refinement 10 mm → 1 mm◇ Uniform through-thickness deformation◇ Shear deformation by ECAP◇ Uniform distribution of fine carbidesand nitrides◇ Multi-variant technology◇ Controlled cooling◇ Construction of electromagnetic magnet (- Deriving the method for accelerating the formation of stable a-FeOOH - Development of weathering steel and coating technology for seaside atmosphere (Airborne salt content : ≤1.0mg/d㎡ /day) POSLABHIPERS-21 POSLABKey Technology for Weathering Steel POSLABCoating for stable rust Development of Matrix Steel NaCl, g-FeOOHa-FeOOHCaS and CaOAlcalic atm.Steel Matrixa-FeOOH byreagentNaClBreakthrough : · Acceleratiion of a-FeOOH formation by CaO and CaS inclusion· Acceleration of a-FeOOH formation by coatingHIPERS-21 POSLABEffects of Ca and S on Seaside Corrosion ResistanceAnti-corrosion Mechanism of 0.007Ca-0.008S Steel(CaS + H2O  Ca2+ + OH- + HS- Acceleration of fine a-FeOOH formation)Scanning Vibrating Electrode Technique- Electrolyte : 3.5%NaCl- Specimen : exposed for 480cycles0 . 0 0 0 3 C a - 0 . 0 0 6 S 0 .0 0 7 Ca - 0 .0 0 8 SAccelerated Corrosion Test· Salt spray -Wet-Dry ·4hrs/cycle· 1.0Ni-0.4Cu-Ca-S Steel05101520253Ca-60S4Ca-100S8Ca-130S30Ca-60S70Ca-80SSMA50BWGeneralA l l o y D e s i g n a t i o n ( u n i t : p p m )CorrodedDepth(¥ìm)C o r r o s i o n o f 2 4 0 4 8 0C o r r o s i o n o f 0 2 4 0¡Ü¡ãPOSLABHIPERS-21 POSLAB0 20 40 60 80 100 120 140 160 180 200 220 2404 . 55 . 05 . 56 . 06 . 57 . 07 . 58 . 0C1 0ppm CaC2 1 1ppm CaC3 2 0ppm CaC4 5 7ppm CaC5 6 0ppm Ca -0.23 S iC6 6 4ppm Ca -0.39 S iC7 6 8ppm Ca -0.62 S iC8 6 0ppm Ca -0.3C uC9 6 0ppm Ca -0.6C upHT i m e ( m i n )- Change of pH with time under thin electrolyte film(Electrolyte : distilled water)Anti-corrosion Mechanism of Ni-Si-Cu-Ca-S Steel POSLAB-2 -1 0 1- 8 0- 7 0- 6 0- 5 0- 4 0- 3 0- 2 0- 1 0010Membranepotential[mV]R a t i o o f c o n c e n t r a t i o n o f K C l s o l u t i o n s [ l o g ( CI/CII)]C 1 0 p p m C aC 2 1 1 p p m C aC 5 6 0 p p m C a - 0 . 2 3 S iC 6 6 4 p p m C a - 0 . 3 9 S iC 7 6 8 p p m C a - 0 . 6 2 S i- Cl ion permeability of rust :Si  Suppression of Cl ion permeabilityHIPERS-21 POSLABSurface Treatment for Stable Anti-corrosion Rust Surface treatment foranti-corrosion rustα-FeOOHγ-FeOOHβ-FeOOHFe3O4Fraction of α-FeOOH:Bare  below 30%,Coated  above 70% Evaluation of surface treated plate(Air-borne salt 1.0mdd, 13 months) Criterion for Anticorrosion rust(Fraction of α-FeOOH> 50%)POSLABSteel Matrixa-FeOOHNaClButyl-alcohol resin + Al3+, Ni2+, SO42-, NO3-, O2, H2OHIPERS-21 POSLABSummary and Future Developing Plan1.By adopting SIDT technology and dual phase structure, fine grained structuralsteel with 5 um ferrite grai。