Descaling methods and grading of steel structures

A large amount of steel is needed in the design of steel structure project, but if the steel used in construction rusts a lot, it will greatly shorten the service life. For personal safety is also a challenge, the collapse of the house is common, in recent years more and more attention, today Fangtong steel structure will teach you some rust removal methods!

1、Descaling by pickling

It is to put the steel member to be painted in the acid pool, and remove the oil and rust on the surface of the member with acid. The efficiency of the pickling process is also high, and the rust removal is more thorough, but after pickling, the components must be rinsed with hot water or water, and if there is residual acid, the corrosion of the components will be more powerful.

2、Descale manually

It is to remove the rust on the steel components by manual labor with some relatively simple tools, such as scraper, grinding wheel, emery cloth, wire brush and other tools. This method has low working efficiency, poor labor conditions and incomplete rust removal.

3、Sandblast and descale

It is the use of compressed air pressure, continuous quartz sand or iron sand impact on the surface of steel components, the surface of the steel rust, oil and other debris clean up, revealing the metal steel color of a rust removal method. This method has high efficiency, removes rust thoroughly, and is a more advanced rust removal process.

How to classify the steel structure rust grade?

Grade A: Steel surfaces that are fully covered with oxidized skin and almost free of rust.
Grade B: Steel surface that has been rusted and part of the oxide skin has been peeled off.
Grade C: the oxide skin has been peeled off due to corrosion or can be scraped off, and a small amount of pitting of the steel surface
Grade D: Steel surfaces on which the oxide skin has been completely peeled off due to corrosion and generalized pitting has occurred.

Construction method	Characteristics of Applicable Coatings			coatings	Use of tools or equipment	Main advantages and disadvantages
Construction method	Drying speed	Viscosity	Variety	coatings	Use of tools or equipment	Main advantages and disadvantages
brushing	Dry and slower	low plasticity	Oil-based paints Phenolic paint Alkyd paint, etc.	General components and buildings, various equipment piping, etc.	Various brushes	Low investment, simple construction method, suitable for all kinds of shapes and sizes of the area of the coating; drawbacks are less decorative, low construction efficiency
Hand rolling method	Dry and slower	low plasticity	Oil-based paints Phenolic paint Alkyd paint, etc.	Components and management of large planes in general, etc.	rollers	Less investment, simple construction method, suitable for large area coating; drawbacks with the brush coating method
dip coating	Appropriate dryness, good leveling, moderate drying speed	Good thixotropy	Various synthetic resin coatings	Small parts, equipment and machine components	Paint dipping tanks, centrifugal and vacuum equipment	Less investment in equipment, simple construction methods, less loss of paint, suitable for the construction of complex components; the disadvantage is that the leveling is not very good, there is a phenomenon of hanging phenomenon, pollution phenomenon, the solvent is easy to volatile
air spraying method	Fast evaporation and moderate drying	low viscosity	Various nitro lacquers, rubber lacquers, construction vinyl lacquers, polyurethane lacquers, etc.	Various large components and equipment and piping	Spray guns, air compressors, oil/water separators, etc.	Smaller investment in equipment, more complex construction methods, construction efficiency is higher than the painting method; the disadvantage is that the consumption of large doses, pollution phenomenon, easy to cause a fire
mist spraying	Coatings with only high boiling solvents	Highly nonvolatile, thixotropic	Paste-based coatings and high nonvolatile coatings	Various large steel structures, bridges, pipelines, vehicles, ships, etc.	High-pressure airless spray guns, air compressors, etc.	Larger investment in equipment, more complex construction methods, higher efficiency than the air spraying method, can obtain a thick coating; the disadvantage is that it also needs to lose part of the paint, less decorative