PROSES PEMBUATAN BAJA

Modul 2 &3 Steels Making IPBMPRODI MESIN

Steels Making 122PROSES PEMBUATAN BAJA

D.R.ISpong IronHow is Steel made-I

4

MODEL BLAST FURNACE Udara Panas

BIJI BESI ( IRON ORE)Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, deep purple, to rusty red.

The iron itself is usually found in the form of magnetite (Fe3O4), hematite (Fe2O3), goethite (FeO(OH)), limonite (FeO(OH).n(H2O)) or siderite (FeCO3). Hematite is also known as "natural ore", a name which refers to the early years of mining, when certain hematite ores containing up to 66% iron could be fed directly into iron-making blast furnaces. Iron ore is the raw material used to make pig iron, which is one of the main raw materials to make steel. 98% of the mined iron ore is used to make steel.[1]Nama Meneral ( Iron Ore)

Lanjutan

BENTUK IRON ORE

PELETBRIQUETTESSINTERNODULESProses Reduksi Blast furnace

3Fe2O3+CO 2Fe3O4+ CO2Fe2O3+CO 2FeO + CO2

Lame stone : Batu Kapur ( Kalsium Karbonat CaCo3) untuk menghasilkan terak (slag)CaCo3====>CaO+CO2(terak)FeS+CaO+C=====>Fe+CaS+CO(terak)

Zone of Fusion: It is the zone where carbon ( C ) reacts with ferric oxide (FeO ) to give Iron ( Fe ) at 1300cFeO + 3C Fe + 3Co CO2+ C 2CO

LOGAM CAIR /PIG IRONBlast- furnace

STEEL MAKING PROSES O.H.F/B.O.F

LADLE-FURNACECONTINOUS CASTINGLOGAM CAIRTERPEDO-CAR

Desulfurisasi , Kandungan Sulfur diturunkan(S,P,Si)CaC2,CaO,Mg,Na2OProses pemurnian I (C,P,S,Si) dengan CO2 atau O2RH VACUM DEGASSINGPemurnian II:

Strong StirMenurunkan InclusionsMenurunkan CBASIC-OXYGEN FURNACE(B.O.F)

Open Hearth ProcessPerubahan % Unsur B.O.F

Proses Iron ore Besi Sponge

Iron-OreProses Iron ore- Sponge

Electrical Furnace- Pemaduan unsur logam

Continous casting

Menurunkan biayaMemperbaiki kualitasMeningkatkan sifat mekaniknya

Hasil-Continous castingBloomSlabBilletREHEATING HOT ROLLINGCOLD ROLLINGPICKLING PROSES1370 o C1315oCH2SO4HCL40 s.d 70 %

Hot Rolling [ 1200oC]

IIIIIITujuan Cold RollingMemperbaiki kualitas permukaan;Memperbaiki ukuran/bentuk ;Hasil Cold rollingLogam menjadi keras [mampu bentuknya rendah]Cara memperbaiki ;1. Dengan melakukan Annealing [705oC]2. Pendinginan lambat sampai [90oC]Proses Pengerolan

Cold Rolling dilakukan pada suhu di bawah Temperatur rekristalisasi

OperatorRol Bagian Atas Pelat Hasil PengerolanAnnealing after cold rollingBox annealingContinuous annealing

Logam menjadi lunakTerjadi RekristalisasiButir Memanjang Butir equaxialTEMPER ROLLING MENURUNKAN PENGARUH DARI STRAIN AGINGMEMBENTUK : UPPER & LOWER YIELDING

Struktur MikroNama Meneral Komposisi KimiaPenamaan

Oxide: Magnetite Hematite Ilmenite Limonite

Fe3O4Fe2O3FeTiO3HFeO2*Fe2O(OH)**

Ferrous-Ferric oxideFerric-OxideIron-titanium oxide}Hydrous iron oxide}

Carbonate Siderite

FeCO3Iron carbonate

Silicate Chamosite Stilpnomelane Greenalite Minnesotaite GruneriteIron Silicates

Sulphide Pyrite(iron pyrites) Marcasite(white iron pyrites) Pyrrhotite(Magnetic iron pyrite)FeS2FeS2

FeS

Iron Sulfide

Ferrous Alloy

Plant Karbon Steel

Steel

Low Alloy Steel 8% Alloying Element

Low Carbon Steel(0.5%C)

Corrosion Resistant

Heat Resistant

Wear Resistan

Ferritic

Ferritic-Pearlitic

Pearlitic

Martensitic

Bainitic

Austenitic

Precipation-Hardened

Austenitic-Ferritic

Duplex Structure