This high speed, continuous annealing process removes internal stresses induced during cold rolling and allows desired mechanical properties to be developed in Advanced High Strength Steel and Tinplate strip by following pre-determined heating and cooling profiles.
Cold rolled coils are either batch annealed(BA) in vertical stacks of typically 4 or 5 coils high, covered by a bell shaped furnace jacket or in a continuous annealing furnace found as either a stand-alone process line (CAL) or as part of a continuous galvanizing or galvannealing line (CGL/CGAL). In both processes the steel is heated and cooled in a controlled manner to allow re-crystallisation to occur which reduces its hardness and strength, returning it to a more ductile state suitable for further working or tempering. In most cases where surface oxidation should be avoided, annealing takes place in an inert or endothermic gas mixture combination of either carbon monoxide, hydrogen or nitrogen gas.
Annealed strip is inspected at the end of a continuous annealing line usually after in-line temper rolling to ensure surface defects have not been introduced by this process or in the case of batch annealed strip after further rolling in a stand-alone temper mill or skin-pass mill before recoiling. Manual surface inspection is difficult in either of these operations, so a real-time automated solution is essential.
EXAMPLE CUSTOMER INSTALLATION
(Click each image to enlarge)
The images below show a typical installation of a SmartView Inspection System in a continuous annealing or other heat treatment line to supply defect-free coated strip, mainly for the battery industry. This particular line normalizes the strip (a type of annealing process) before electroplating with copper, brass, nickel-cobalt or nickel-zinc, and both top and bottom sides of the coated strip are inspected in real-time.
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The lights and cameras are installed on customer-supplied mounting frames with heavy-duty guards to prevent damage to lights from strip breaks.
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| Image shows air blower connection to light to maintain optimum operating temperature for maximum life of LED modules. |