Complex protective coating of sink roll used for hot dip coating and preparation method

Abstract

The invention discloses a complex protective coating of a sink roll used for hot dip coating and a preparation method. The complex protective coating comprises a bottom layer, a transition layer and a working layer; the bottom layer is a CoCrW coating, the transition layer is a coating of a mixture formed by CaO-SiO2 and CoCrW according to a proportion, and the working layer is a CaO-SiO2 coating; and a thermal expansivity relation among the coatings and a thermal expansivity relation among the coatings and a roll body are set. Coating is performed on the bottom layer by means of high velocity oxygen-fuel equipment, coating is performed on the transition layer and the working layer by means of plasma spraying equipment, corresponding technological parameters are set in the coating forming processes, and accordingly the complex protective coating on the surface of the sink roll is obtained. According to the complex protective coating provided by the invention, through design on the coating structure, good thermal expansion matching between the complex protective coating and base metal of the roll is achieved, and the purpose that the complex protective coating can be applied to practical production stably in a long term is achieved; and the preparation method is easy to operate, and the complex protective coating on the surface of the roll can be prepared and obtained.

Description

Technical field

[0001] The invention relates to a composite protective coating of a sinking roller for hot dip plating and a preparation method. Background technique

[0002] At present, most anti-corrosion steel products must be hot-dip galvanized. Hot-dip galvanizing technology has become the most economical and effective method for steel anti-corrosion applications. Hot-dip galvanized sheets have good corrosion resistance, processing formability, weldability, Paintability and environmental protection are widely used in many manufacturing fields such as construction, home appliances, vehicles, vessels, containers, and electromechanics.

[0003] In the continuous hot-dip galvanizing production line, the zinc liquid is strongly corrosive to all parts in the zinc pot, especially the sunken roller, the surface condition of which is very important and directly affects the surface quality of the steel plate. In actual production, due to the corrosion of the zinc liquid on the parts an...

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