Stefano Martines Tenova SpA - Strip Processing Lines Combined Annealing and Pickling Line New Technologies & Techniques applied on recent Projects

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1 Stefano Martines Tenova SpA - Strip Processing Lines Combined Annealing and Pickling Line New Technologies & Techniques applied on recent Projects September 2011

2 Tenova Strip Processing: a long history 1927: Aetna Standard (USA) starts strip processing line s business 1987: ITALIMPIANTI (designing Processing Lines since the 77) acquires Aetna Standard s strip processing business 1995: TECHINT acquires the Strip Processing business of Italimpianti 04/06: TECHINT acquires Presind Automation and integrates electrical and automation competencies for strip processing lines; establishes Key Technologies for Acid Regeneration Plants 2008: TENOVA is born from Techint group (network of companies supplying technologies for the metal and mining industries) 2009: TENOVA incorporates Multiform (India) and I2S (USA) for cold rolling mills and processing lines 2

3 Stainless Steel Lines: a long tradition Starting from Aetna Standard SS important projects followed in Italy - Cold-APL (1990) - Bright Annealing (1994) - Combined APLs major revamping called LAF 1 (1994) and Line 4 (1995) - Hot-APL called LAC2 (1999), Tenova confirmed its competencies in SS Thanks to a very good result of the LAC 2 in terms of productivity, strip quality and plant reliability, Tenova was awarded for the supply of: - new high productivity Cold APL called LAF4 in 2003 (350 kt/y). 3

4 Stainless Steel Lines: a long tradition Then other two projects followed: Bright Annealing Line (BAL 1) in Mexico (2006) Bright Annealing Line (BAL 3) ) in Italy (2008) 4

5 ANNEALING & PICKLING LINE: AN ESSENTIAL IN STAINLESS STEEL COLD ROLLING CYCLE STAINLESS STEEL STRIP: Cold Rolling cycle (conventional) AISI 300 AISI 400 H-APL BAF CRM C-APL BA SPM 5

6 ANNEALING & PICKLING LINE: AN ESSENTIAL IN STAINLESS STEEL COLD ROLLING CYCLE STAINLESS STEEL STRIP: Cold Rolling cycle through the Combined APL AISI 300 AISI 400 Combi-APL BAF Suitable for small cold mill plant as a first step or as a flexible line in case of important production CRM BA SPM 6

7 The Line LAC 4 project : a flexible Combined Stainless Steel APL Line start up: Winter 2009 /2010 Scope of the job: Design and supply of new Equipment Transfer and revamp several re-used equipment from a shut off plant. Main line parameters: Productivity: 50 t/h (max) H. R. SS Thickness: mm C.R. SS Thickness: mm Width: mm 7

8 The Line LAC 4 project : a flexible Combined Stainless Steel APL The project main guide lines were: to modernize the plant, making (or prearranging) possible improvements, avoiding significant changes of the operator interface, operation standard practices and receipts. to replace obsolete equipment in order to improve strip tracking and quality to minimize environmental impact to minimize civil works (taking in consideration existing galleries for fluids and effluents from other lines, new safety galleries and corridors) to allow following steps, improving product quality and productivity, with future minor upgrading. 8

9 The Line LAC 4 project : New and consolidated technologies Mechanical equipment The new looper car, of the 4-strand type is provided with two steering rolls on boars operating in an inclined plane in order to have the proportional integral correction mainly useful during the passage of cambered tail and head ends. The looping arms are actuated by a cam mechanism according to the Tenova s no-scratch design suitable also for cold rolled material: the strip strands are completely supported by rollers arms fixed on board of the car, during the opening-closing phase. 9

10 Mechanical equipment Driven Deflector & Steering rolls: Useful to: -compensate the high roll inertia typical in Combined lines -improve the strip tension control (improving the bridles delta tension capability) 10

11 The Line LAC 4 project : New and consolidated technologies Annealing Furnace The furnace sections (By Tenova LOI-Italimpianti) New Furnace with fumes Preheating chamber, driven up&down rolls Innovative multimedia cooling section is composed of air+light fog, fog and a final sprayed water section; special ramps have been installed to modulate the cooling effect along the width of the strip (center versus edges) to get homogeneous temperature gradient and strip flatness. 11

12 The Line LAC 4 project : New and consolidated technologies Special Mechanical equipment Thermoflattenig Steering rolls Useful to: Eliminate (partially) the strip camber at the exit of the Annealing Furnace reducing slightly the strip tension on the longer edge Improving the strip tracking along the pickling and exit sections 12

13 The Line LAC 4 project : New and consolidated technologies Pickling section New pickling section circulating system and acid management New brushing machines High turbulence Pickling tanks New pickling section rinsing and drying 13

14 The Line LAC 4 project : Pickling section COMBINED LINES: Hot/Cold APL Traditional lay out include Shot blasting (used only for Hot coils) and long Na 2 SO 4 electrolytic tank not optimized for Hot coils (efficiency much lower than H 2 SO 4 ). Scale Breaker Shot Blasting Na 2 SO 4 Electrolytic Brush Mixed acid Mixed acid Rinse and Brushing Very important advantages are obtained from the new technologies based on H 2 SO 4 at controlled Temperature Scale Breaker Shot Blasting H 2 SO 4 Electrol. DC or AC+DC Brush Mixed acid Mixed acid Rinse and Brushing The new H2SO4 AC+DC has a very high flexibility : very high efficiency with Hot and Cold coils Hot coil with reduced use of shot blasting and reduced Mixed acid pickling load Cold coil: high efficiency, reduced Mixed Acid load, Cr6+ absent in the waste acid! Very high quality (Not Shot blasted) Hot strip can be produced with limited speed limitation 14

15 Annealing & Pickling Lines: acid de-scaling section The H2SO4 electrolytic shallow tank tested from 2003 in the line LAF 4 : operated with sulphuric acid at controlled Temperature Characterized with: -an optimum descaling effect with a superior efficiency -the high efficiency allow a reduced mixed acid consumption (in the following tanks) -reduced voltage and consequently electrical energy consumption -Cr 6+ absent: in acid ambient chromium is not present as hexavalent ions - Cr 6+ reduction plant eliminated for the waste pickling solution as well for the waste rinsing water 15

16 Annealing & Pickling Lines: pickling section PICKLING TANKS MAIN FEATURES: Shallow tanks for increased turbulence Turbulent pickling for higher efficiency and a shorter pickling time designed to be operated with conventional Nitric+Fluoridric acid or Nitric free ecological mix of acid : in this case nitric acid is not used and consequently nitrates in waste solutions and NOx in the fumes are eliminated 16

17 Annealing & Pickling Line: Pickling tank FEM modelling Picture: liquid flow speed field (m/s) close to the strip (grey) and at the side wall Significant turbulence and local recirculation close to the strip (velocity up to 1 m/s). Higher flow at strip inlet where vessel depth is lower. Flow circulations are asymmetrical due to the staggered nozzle design. 17

18 Annealing & Pickling Line: Pickling tank FEM modelling Picture: liquid flow field at tanks walls and bottom Significant liquid turbulence induced by both strip and nozzles. 18

19 The Line LAC 4 project : Pickling section The adopted technical solutions and their harmonic assembly in the line lay out allowed the production of coils having a very high quality standard starting from the first month after hot commissioning 19

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