2 1 Classification of Rolling Mills Institut für

2. 1 Classification of Rolling Mills Institut für Metallurgi Werkstoffumformung . . . following • Number of rolls 2 -, 3 -, 4 -, 6 -, 12 -, 20 -high rolling mill • Type of stands Mill housing, Roon tilting frame, Sendzimir, Steckel, multi roll CRM, Planetary RM, Pilger mill • Type of rolls Smooth, patterned, grooved rolls • Product Flat, section, sheet, strip, wire, tube, . . . mill • Configuration of stands Single, open-type, conti, horizontal, vertical, . . . mill • Working temperature Hot / cold RM common: heating up: hot rolling B Fundamentals TFV Rolling of flat material 1

2. 1 6 -High with Cross-Crown-Control B Fundamentals Institut für Metallurgi Werkstoffumformung TFV Rolling of flat material 2

Institut für Metallurgi 2. 1 12 -High stand Werkstoffumformung 12 -roll application for combined 4/12 -roll stand B Fundamentals TFV Rolling of flat material 3

Institut für Metallurgi Werkstoffumformung 2. 1 20 -roll stand B Fundamentals TFV Rolling of flat material 4

Institut für Metallurgi 2. 1 Classification of rolled products Werkstoffumformung Semi-finished and finished products Semi-finished Finished Sections Flat products Sheet Slab, bloom, billet, sheet bar Bar, beam, special section, rails, piling section, wire, tube B Fundamentals Plate and medium plate Strip Hot wide strip, narrow strip TFV Rolling of flat material 5

Institut für Metallurgi 2. 1 Classification of finished flats • Hot rolled Werkstoffumformung Wide flats Plate (thickness > 3 mm) (thickness < 3 mm) Strip • Cold rolled Heavy plate Sheet Hot wide strip Steel hoop (width > 600 mm) (width < 600 mm) Cold wide strip Cold strip (width > 600 mm) (width < 600 mm) Sheet Strip B Fundamentals TFV Rolling of flat material 6

Institut für Metallurgi 2. 1 Rough material Werkstoffumformung Bloom square for billet, round material and sections side length > 120 mm : pre-shaped for sections near-net shape Billet same as bloom with side length between 50 – 120 mm Slab rectangular cross section for flat products Roughed slab rectangular cross section rolled out of a bloom B Fundamentals TFV Rolling of flat material 7

Institut für Metallurgi 2. 1 Classification by rolls Werkstoffumformung Smooth or patterned rolls Characterised by roll barrel length e. g. 80“-mill: roll barrel length W=2030 mm Utilization width: 65 – 95 % Calibrated rolls Characterised by barrel diameter of rolls not by diameter of groove! 750 -Bloom Mill: Roll diameter D = 750 mm 4 -high mills (often) Both data (roll barrel diameter and length) 1420/585Ǿ * 2030 mm B Fundamentals TFV Rolling of flat material 8

Institut für Metallurgi 2. 1 Classification of Hot Rolling Mills 1 st heat Werkstoffumformung Bloom / slab from casting shop rolled without reheating Blooming mill Rail and beam mill Mill for semi-finished products (e. g. billets) Heavy section mill Plate mill Hot strip mill (CSP-, ISP-, DSC-plant) 2 nd heat Medium and small section mills Wire rod mill 5. 5 -4. 5 mm with ca. 2000 m/min Plate mill rolled from roughed slab Tube mill B Fundamentals TFV Rolling of flat material 9

2. 2 System of forming processes Institut für Metallurgi Werkstoffumformung 1 - Deformation zone 2 - Area in front of deformation zone 3 - Area behind deformation zone 4 - Area between tool and workpiece 5 - Tools for deformation 6 - Outside contacting area workpiece / tool 7 - Machinery 8 - Surrounding area of machinery B Fundamentals TFV Rolling of flat material 10

Institut für Metallurgi Werkstoffumformung Stress 2. 2 Stress-strain curve and true stress Strain B Fundamentals TFV Rolling of flat material 11

2. 2 Flow stress curves for special steel and aluminium qualities Institut für Metallurgi Werkstoffumformung Flow stress kf normalgeglüht weichgeglüht gepresst geglüht gezogen = = = normalised soft annealed extruded annealed drawn True strain Flow stress kf True strain B Fundamentals TFV Rolling of flat material 12

2. 2 Flow stress curves under different temperatures and strain rates Institut für Metallurgi Werkstoffumformung Flow stress kf Deformation temperature Strain rate True strain B Fundamentals TFV Rolling of flat material 13

2. 2 Flow stress curves for steel as a function of T, φ and dφ/dt Institut für Metallurgi Werkstoffumformung Flow stress kf True strain Strain rate Deformation temperature B Fundamentals TFV Rolling of flat material 14

2. 2 Principle flow stress of steel as a function of temperature Institut für Metallurgi Werkstoffumformung Steel 100 Cr 6 Flow stress kf Blue brittleness Phase transformation B Fundamentals TFV Rolling of flat material 15

2. 3 Fundamentals of Steel Properties Institut für Metallurgi Werkstoffumformung Formability of materials Ceramics Glasses Wood Natural fibres Plastics very low minor limited Metalle „without limits“ Regeneration Movability of atoms Movement of dislocations Recrystallisation . . . Constant mass: Volume B Fundamentals constant! TFV Rolling of flat material 16

2. 3 Fundamentals of Steel Properties Institut für Metallurgi Werkstoffumformung Allotropy of iron α- (δ-) – Fe: Ferrite γ- Fe: Austenite B Fundamentals TFV Rolling of flat material 17

2. 3 Fundamentals of Steel Properties Institut für Metallurgi Werkstoffumformung Alloying elements • Interstitial • Substitution • Cluster interstitial substitution Dissolved carbon atom Space lattice of iron C - Solidification, equilibrium - Segregation B Fundamentals Fe Alloying elements Dissolved alloying atom Space lattice of the precipitated carbide TFV Rolling of flat material 18

2. 3 Fundamentals of Steel Properties B Fundamentals Institut für Metallurgi Werkstoffumformung TFV Rolling of flat material 19