Engineering company ENCE GmbH in partnership with ANDRITZ METALS, Germany SUNDWIG GmbH supplies complex hot galvanizing lines of the cold-rolled steel strip have the annual output ranging from 60 to 500 ths. tons per year.
Coiled steel galvanizing is the most common corrosion protection method. The automated high-speed hot galvanizing lines include the following sections, assemblies, and machines:
- Input section:
- Coil rack
- Loading carriage
- Dual decoiler system
- Alternative operation of decoilers, coil weight 10 to 40 t
- Two thickness gages
- Designed for initial strip thickness control
- Dual guillotine shears
- for cutting the beaded edges of the strip in the alternatively used coils
- Butt-welding machine
- Butt-welding machine is equipped with straightener rollers and performs welding of strip ends of two coils; weld thickening no more than 10%, weld strength no less than 85% of the main strip characteristics
- Looping pit
- Disc shears
- Designed for cutting the strip side edges; shearings are cut up by scrap cutter
- Stretching machine
- Stretching rollers
- Multistorey storage loop (accumulator)
- Automatically monitors the strip stock and has end trolley for constant stretching of the strip.
- Strip electrochemical cleaning section
- The strip is cleaned in baths with alkali solution; after that, it is washed and dried in a way similar to that described for the strip pickling line above.
- Strip hydro-dynamic cleaning section
- Guide rollers
- Two vacuum housings
- Dual rotary blowers
- Dual high-pressure pumps
- Two cyclone separators
- Circulation water treatment system
- Strip thermal treatment section
- Strip tensioning regulator
- Scale-free heating furnace
- The strip is heated up to 450–470°C to burn the grease residues; this is followed by metal annealing to 730–950°C, depending on the material.
- Strip jet cooling unit
- The unit operates under staged accelerated cooling principle and includes the following:
- Cooling chamber body with lining layer
- Fan
- A set of water-cooled tube-type heat exchangers
- A system of nozzles for jet supply of shielding gas to the strip
- Shielding gas automatic control system
- Decay chamber
- Operates at temperature about 500°C.
- Strip galvanizing section
- Inclined channel (section)
- Filled with shielding gas and protects the heated strip (500°C) from air contact
- Bottom immersed drum with stellen or ceramic journal bearings
- Stabilizing roller with journal bearings
- Correcting roller with journal bearings
- Noncontact jet device for coating thickness control
- Electromagnetic strip stabilizer built on air doctor (EM-stabilizer)
- Bath heating system
- Removable inducers
- Gas burners
- Immersion ceramic heaters
- Strip cooling section
- Metal tempering furnace
- Maintains temperature at 320–350°C
- Strip air-cooling chamber
- Galvanizing coat thickness gage
- Strip straightening and planishing section
- Strip alignment system
- Two planishing stands
- Strip rolling with squeezing 0.5–1.5% which is controlled by induced-pulse sensors and strip tensioning regulators
- Planishing stands is equipped with zinc removal plant for rolls
- Stretch straightening machine (machine for straightening by stretching)
- Passivation bath
- Exit section:
- Strip feeding device
- Vertical storage loop (accumulator)
- A feeding device with a mechanical side guide
- Surface quality control system
- Width control device
- Penetration defects control
- Radiation thickness gage
- Strip electrostatic oiling unit ( strip oiler)
- Dual tension reel for finished strip (coiler)
- Strip marking plant
- Cross-cutting shears for finished strip
- Overhead crane
- Tilting cradles for finished coils
- Finished coils rack
