The invention concerns a continuous pickling plant (101) for the treatment of metal products (109) in the form of a strip or tube which includes a plurality of acid solution process tanks (102) each divided into a plurality of turbulence cells (114) and a recirculation system of the acid solution. The plant also includes, upstream of the plurality of process tanks (102), a device for heating (124; 126) the metal product (109), namely an induction heating (124) system and/or a tunnel with water sprays (126). A solution with only two pickling tanks (102) is also presented. Devices are described (135; 136; 138, 138a) to increase turbulence in the tanks and to accelerate pickling, e.g. by adding fresh acid (146) in the first tank. The invention also concerns a related pickling process. The invention optimizes the effect of the acid and reduces the residence time of the strip (109) in the plant.

Disclosed is a continuous thermal treatment line for a steel strip. The strip passes through consecutive thermal treatment chambers, is quickly cooled in at least one of the chambers by spraying liquid onto the strip, or by spraying a fluid made up of gas and liquid or spraying a combination of gas and liquid forming a mist. After quick cooling, a protective metal layer is deposited on the strip by dip coating. The cooling fluid strips iron oxides or other alloy elements contained in the steel to be treated, minimizing oxidation and reducing the oxides on the strip. Spray pressure and distance are chosen to facilitate the stripping property and the mechanical action of the sprayed fluid, reducing the layer of oxides on the strip. The temperature of the strip at the end of the cooling step is the temperature necessary for carrying out the desired treatment cycle.

A plant for cleaning rolled metal strips provided with a superficial layer of oxide, the plant comprising unwinding means for unwinding at least one coil of rolled strip and pickling means for pickling said rolled strip; wherein there are provided measuring means for measuring the thickness of the superficial layer of oxide, arranged between said unwinding means and said pickling means. A relating cleaning method is also claimed.

Process and device for cooling a steel strip (1) running through the cooling section (2) of a continuous line, whereby cooling is achieved by projecting the strip with an aqueous solution of formic acid with a concentration of formic acid between 0.1% and 6%, and preferably between 0.5% and 2%.

A water-based grinding machine for polishing a surface of a metal strip includes an unwinding wheel, a polishing mechanism, a cleaning mechanism, a drying mechanism and a winding wheel. The polishing mechanism includes a first polishing wheel and a first workbench. The metal strip is drawn from the unwinding wheel into a gap between a polishing wheel and a pad, and then is drawn to the cleaning mechanism. The cleaning mechanism includes a third workbench and a cleaning liquid storage tank. At least one pair of felt wheels is arranged above the third workbench. The metal strip passes through a gap between the at least one pair of felt wheels. An outer circumference of the at least one pair of felt wheels is covered with a wool layer. The cleaning liquid storage tank is provided with a cleaning pipe. The drying mechanism includes an oven.

Continuous annealing equipment (1) including a cleaning device (11, 12) for performing a cleaning treatment on a steel strip (S) and an annealing device (12) for performing an annealing treatment on the steel strip (S) comprises an exhaust gas passage (31, 41) through which an exhaust gas discharged from the annealing device (12) flows, a solution circulation passage (32, 51) through which a cleaning solution used in the cleaning device (11, 12) circulates, and a heat exchanger (53) which forms a part of the solution circulation passage (32, 51) and contacts with the exhaust gas.

A plant for cleaning rolled metal strips provided with a superficial layer of oxide, the plant comprising unwinding means for unwinding at least one coil of rolled strip and pickling means for pickling said rolled strip; wherein there are provided measuring means for measuring the thickness of the superficial layer of oxide, arranged between said unwinding means and said pickling means. A relating cleaning method is also claimed.

Process and device for cooling a steel strip (1) running through the cooling section (2) of a continuous line, whereby cooling is achieved by projecting the strip with an aqueous solution of formic acid with a concentration of formic acid between 0.1% and 6%, and preferably between 0.5% and 2%.

The invention concerns a continuous pickling plant (101) for the treatment of metal products (109) in the form of a strip or tube which includes a plurality of acid solution process tanks (102) each divided into a plurality of turbulence cells (114) and a recirculation system of the acid solution. The plant also includes, upstream of the plurality of process tanks (102), a device for heating (124; 126) the metal product (109), namely an induction heating (124) system and/or a tunnel with water sprays (126). A solution with only two pickling tanks (102) is also presented. Devices are described (135; 136; 138, 138a) to increase turbulence in the tanks and to accelerate pickling, e.g. by adding fresh acid (146) in the first tank. The invention also concerns a related pickling process. The invention optimizes the effect of the acid and reduces the residence time of the strip (109) in the plant.

Disclosed is a method for continuous thermal treatment of a steel strip. The strip passes through consecutive thermal treatment chambers, is quickly cooled in at least one of the chambers by spraying liquid onto the strip, or by spraying a fluid made up of gas and liquid or spraying a combination of gas and liquid forming a mist. After quick cooling, a protective metal layer is deposited on the strip by dip coating. The cooling fluid strips iron oxides or other alloy elements contained in the steel to be treated, minimizing oxidation and reducing the oxides on the strip. Spray pressure and distance are chosen to facilitate the stripping property and the mechanical action of the sprayed fluid, reducing the layer of oxides on the strip. The temperature of the strip at the end of the cooling step is the temperature necessary for carrying out the desired treatment cycle.