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TERM PROJECTFERROUS & NONFERROUS200823104 BYOUNGUK KWON200923171 JUNGHYUK LEE200923198 EUNPYO HONG201223109 DAYOUNG KIM201223151 AYOUNG OHINDEX 01 Topic selection02 Design concept 03 Detailed design04 Expected result05 Restrictive condition01 TOPIC SELECTION The Background

OffshorePlant

errite-based steel development at extremeenvironment of the offshore ocean plantF.4PurposeDuctility Brittlenessat extremely low temperature ( fall to 55 degrees below zero ) High strengthBecause of extremely low temperature and heavy pressure of abyss High toughnessthat have strong properties because of high resistance for deformation Focus on developing a material that have high toughness & strength.502 Design concept

6BASE METALAPI 2W

MICROSTRUCTURECOMPOSITION & MECHANICAL PROPERTY- Ferrite(white)- Pearlite(dark brown)- Bainite(gray)Base metal7Design concept01 Grain size refiningStrength

Enlarging grain boundary range Becoming smaller grain sizeHall-petch relationship y = i + kd -1/2 y = yield strength i = disturbing friction stress about dislocation movement in grain k = constant d = grain diameter

Yield strength & grian size8Design concept01 Grain size and refining

Particles smaller

dislocation(producing cracks)

Generated cracks have many obstacles

magnify XToughness Transition temperature not easily brittle fracture

9Design concept02 Dispersion hardeningReinforced materials by adding to secondary phase as oxide, nitride, boride and carbide

carbon combine with other elements Carbide fomer : TI, V, Nb, Mo, Cr and W

Make steel hard and strong 10Design conceptGrain size refiningStrength improvement through Grain miniatureExcellent toughness at lower temperature by lowering the DBTT temperature for steelDispersion hardening improve strength by a carbide extraction1103 Detailed concept

Grain size refininga01 Grain size refining By adding Nb during TMCP

Temperature of coarsening

13Grain size refining

950 Controlled rolling Rolled Prociding nucleation site

14Grain size refining

500 Accelerated coolling process

15Grain size refiningekAr A(500c) temperature As accelerated cooling process (10c/sec) martensite or bainit (transformation) Reheating(900c)Nb precipitate Pinning effectprevents austenite grain growth Austenite not recrystallization many heterogeneous ferrite nuclation sitesSTEP 1STEP 2STEP 3GRAIN SIZE REFININGThe offshore ocean plant consist equipment that excavates resources underneath the ocean (oil, natural gas, tidal energy, etc). Although our country possesses high-tech machineries to derive high quality products and have the man power for construction work, we lack the knowledge to design and build offshore plants. As a result, we heavily rely on foreign corporations regarding this issue. Thus, there is an urgent need for us to develop our own unique way to construct offshore plant. Also, if we acquire the design, apparatus, material, and management technology with respect to offshore plant early in advanced we will be able to dominate the market of offshore plant in extreme environment. For such reason, our objective is to develop a ferrite-based steel for the use of extreme environment such as offshore ocean plant.

16Dispersion hardening

02 Dispersion hardening17Dispersion hardening

Extractions as NbCN, VCN, TiC NaCL structureNot suitable for the lattice of ferrite Incoherency (ferrite & extraction) strength 1804 Result expectation

Result expectationIn conclusion, Improved yield strength & tensile strength

Demand characteristics for TMCP20Result expectationToughness improve at low temperature By lowering transition temperature

Yield strength improveGrain size refining is induced by adding to alloy element Nb 21Result expectation

Strength improveLattice distortion is generated because of misfit between lattice by forming carbide in ferrite matrix2205 Realistic limit condition23Realistic limit condition The alloy element Nb as design key factorEconomics 1 ton x o.o4 x 0.01 = 0.0004ton = 0.4kg by adding to Nb of 0.04%The price for Nb = $1410 per 1kg 57.2 ten thousand won 0.4kgEnvironment Doesnt influence on the environment because of that adding the amount is very small

Healthy and safety Its using dont have a big problem, because of slightly addition of 0.40wt%

24PORPOSEIndustry standardCompliance with dindustry standardsSocialityContribute greatly to the economic developmentProductivity and durabilityExcellent durability & similar productivityAestheticThat apparently will not be a big problem25RULE: Leader, Overall design , Collect data of alloying elements make final report. : Presenter, Research, Collect the data about concept & detail design. : Translation, Research about offshore plant and API 2w gr.50, Make final report. : Writer, Research about TMCP, Nb and dispersion hardening, Make presentation. : Research about grain size refinement, Make presentation, Realistic limit condition.RULEE26REFERENCE / PD(KEIT PD ), (), (KEIT PD) Progress in thermomechanical control of steel plates and their commercialization ( : Kiyoshi Nishioka1,2 and Kazutoshi Ichikawa3) DONALD R.ASKELAND H.K.D.H. BHADESHIA, R.W.K. HONEYCOMBE Development Trends of Steel Plates for Ship Building andOff-Shore Construction and It's Weldability (Il Wook Han, Young Hwan Park, Gyu Baek An and Young Ho An) API 2W Grade 50 TMCP Structural Steel Plate - www.ssab.comNippon steel & Sumitomo metal - http://www.nssmc.com/Evaluation of Fracture Toughness and Microstructure on FCAWeldment According to Heat Input(Yong-Taek Shin*, Sung-Won Kang** and Myung-Hyun Kim**)Weldability of TMCP type Steel for Offshore Structures (, , )Effects of V on the Formation of Ti-Nb_V Cabonitrides and Mechanical Properties in Low Carbon HSLA Steels - , , Microstructural Unit of Acicular Ferrite - Hee Jin Kim, Ka Hee Kim, Joon Seok Soe, Hoi Soo Ryoohttp://care.kins.re.kr/RRMP/PRGM/FILE/001/SHIN200729103647http://mechbam.tistory.com/2

27THANK YOUQ&APRESENTATION