A heat recovery device including: a warm-water bath storing warm water and a drying chamber, wherein warm exhausted air from the chamber heats the water includes: an exhaust duct that the exhausted air from the chamber to the outside air passes; an exhaust bypass duct between two positions in the exhaust duct; a circulation pipe through which the water circulates; a heat exchanger provided generates air in the bypass duct to be absorbed by water in the circulation pipe; a warm-water bypass pipe between two positions downstream to the heat exchanger in the circulation pipe or between one position downstream to the heat exchanger in the circulation pipe and the warm-water bath; a heatsink provided at the bypass pipe; a first distribution-changing valve for distribution of air flowing from the exhaust duct to the exhaust bypass duct; and a second distribution valve for distributing water to the bypass pipe.

A heat recovery device including: a warm-water bath storing warm water and a drying chamber, wherein warm exhausted air from the chamber heats the water includes: an exhaust duct that the exhausted air from the chamber to the outside air passes; an exhaust bypass duct between two positions in the exhaust duct; a circulation pipe through which the water circulates; a heat exchanger provided generates air in the bypass duct to be absorbed by water in the circulation pipe; a warm-water bypass pipe between two positions downstream to the heat exchanger in the circulation pipe or between one position downstream to the heat exchanger in the circulation pipe and the warm-water bath; a heatsink provided at the bypass pipe; a first distribution-changing valve for distribution of air flowing from the exhaust duct to the exhaust bypass duct; and a second distribution valve for distributing water to the bypass pipe.

A high-gross manufacturing method for magnesium alloy object includes providing a magnesium alloy object; performing micro-arc oxidation or conversion coating treatment on the magnesium alloy object to form oxide film on a surface of the magnesium alloy object; spraying a paint layer on MAO-treated or conversion coating-treated surface of the magnesium alloy object to protect the magnesium alloy object; performing CNC high gross cutting to cut away part of paint layer and part of the oxide film to expose metallic main body; using specific conversion coating solution to passivate the magnesium alloy object; and spraying UV curable paint on the surface of the magnesium alloy object to provide corrosion protection. The present invention also provides a high-gross magnesium alloy structure.

A high-gross manufacturing method for magnesium alloy object includes providing a magnesium alloy object; performing micro-arc oxidation or conversion coating treatment on the magnesium alloy object to form oxide film on a surface of the magnesium alloy object; spraying a paint layer on MAO-treated or conversion coating-treated surface of the magnesium alloy object to protect the magnesium alloy object; performing CNC high gross cutting to cut away part of paint layer and part of the oxide film to expose metallic main body; using specific conversion coating solution to passivate the magnesium alloy object; and spraying UV curable paint on the surface of the magnesium alloy object to provide corrosion protection. The present invention also provides a high-gross magnesium alloy structure.

Disclosed are pretreatment compositions and associated methods for treating metal substrates with pretreatment compositions, including ferrous substrates, such as cold rolled steel and electrogalvanized steel. The pretreatment composition includes: a Group IIIB and/or IVB metal; free fluoride; and molybdenum. The methods include contacting the metal substrates with the pretreatment composition.

Disclosed are pretreatment compositions and associated methods for treating metal substrates with pretreatment compositions, including ferrous substrates, such as cold rolled steel and electrogalvanized steel. The pretreatment composition includes: a Group IIIB and/or IVB metal; free fluoride; and molybdenum. The methods include contacting the metal substrates with the pretreatment composition.

A method for anti-corrosion coating of metal components, in series, comprising a plurality of wet-chemical treatment steps concluding in cathodic electrodeposition, in which method each component is received by a conveying rack; then the component and conveying rack proceed through all treatment steps; the finished coated component is separated from the conveying rack; and an uncoated component is then received by the same conveying rack for coating; wherein build-up of solid coating deposits on the conveying rack is prevented by using an additional treatment step before cleaning/degreasing, passivation and electrodeposition, thereby avoiding extraction of individual conveying elements for removing coating deposits; wherein removal of cathodic electrodeposition coating constituents from conveying racks is achieved by contacting the conveying racks carrying components to be coated with an aqueous acidic agent, containing phosphoric acid, before the wet-chemical treatment steps for cleaning/degreasing, passivation and cathodic electrodeposition.

A method for anti-corrosion coating of metal components, in series, comprising a plurality of wet-chemical treatment steps concluding in cathodic electrodeposition, in which method each component is received by a conveying rack; then the component and conveying rack proceed through all treatment steps; the finished coated component is separated from the conveying rack; and an uncoated component is then received by the same conveying rack for coating; wherein build-up of solid coating deposits on the conveying rack is prevented by using an additional treatment step before cleaning/degreasing, passivation and electrodeposition, thereby avoiding extraction of individual conveying elements for removing coating deposits; wherein removal of cathodic electrodeposition coating constituents from conveying racks is achieved by contacting the conveying racks carrying components to be coated with an aqueous acidic agent, containing phosphoric acid, before the wet-chemical treatment steps for cleaning/degreasing, passivation and cathodic electrodeposition.

An electrodeposition coating method includes a degreasing/cleaning step, a chemical conversion step, and an electrodeposition coating layer formation step. The degreasing/cleaning step includes a degreasing step of ultrasonically vibrating a degreasing solution in which a target object is immersed, using an ultrasonic vibrator. The electrodeposition coating layer formation step includes: a first electrodeposition step; a first rinsing step; a rinse water removal/reduction step of removing or reducing rinse water on a rinse water stagnating surface of the target object; a thermal flow step of allowing the first electrodeposition coating film to thermally flow so that the first electrodeposition coating film formed on a portion of the target object near a first counter electrode has a higher electrical resistance than the first electrodeposition coating film formed on a portion of the target object far from the first counter electrode; and a second electrodeposition step.

An electrodeposition coating method includes a degreasing/cleaning step, a chemical conversion step, and an electrodeposition coating layer formation step. The degreasing/cleaning step includes a degreasing step of ultrasonically vibrating a degreasing solution in which a target object is immersed, using an ultrasonic vibrator. The electrodeposition coating layer formation step includes: a first electrodeposition step; a first rinsing step; a rinse water removal/reduction step of removing or reducing rinse water on a rinse water stagnating surface of the target object; a thermal flow step of allowing the first electrodeposition coating film to thermally flow so that the first electrodeposition coating film formed on a portion of the target object near a first counter electrode has a higher electrical resistance than the first electrodeposition coating film formed on a portion of the target object far from the first counter electrode; and a second electrodeposition step.