KUE Group offer a large range of steel surface preparation services suited to all pipework, steelwork, turbines, tanks, vessels and other steel components.

Correct steel surface preparation is vitally important for a number of reasons:

  • Prepares a surface suitable for coating or lining
  • Improves the service life of the coating or lining
  • Minimises the risk of potential paint defects
  • Removes mill scale and rust
  • Reduces soluble salts (wet blasting) and reduces the risk of corrosion

There are several methods to prepare steel surfaces, depending on the level of contamination and the surface finish required. These include:

  • Grit Blasting
  • Shot Blasting
  • Wet Abrasive Blasting – our System 918 variable low pressure system for removing soluble ferrous salts

Surface Preparation Standards

BS EN ISO 8501-1:2007 is a visual assessment of surface cleanliness that specifies a series of rust grades and preparation grades of steel surfaces. The various grades are defined by written descriptions together with photographs that are representative examples within the tolerance of each grade as described by words and summarised below.

Rust Grades

Rust Grades formatting of A,B,C,D required

A) Steel surface largely covered with adhering mill scale but little, if any, rust.

B) Steel surface which has begun to rust and from which the mill scale has begun to rust.

C) Steel surface on which the mill scale has rusted away or from which it can be scraped, but with slight pitting visible under normal vision.

D) Steel surface on which the mill scale has rusted away and on which general pitting is visible under normal vision.

Surface preparation by blast cleaning is designated by the letters “Sa”

Sa1: Light blast cleaning – When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and from poorly adhering mill scale, rust, paint coatings and foreign matter.

Sa2: Thorough blast cleaning – When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and from most of the mill scale, rust, paint coatings and foreign matter. Any residual contamination shall be firmly adhering.

Sa2½: Very thorough blast cleaning – When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and from mill scale, rust, paint coatings and foreign matter. Any remaining traces of contamination shall show only as slight stains in the form of spots or stripes.

Sa3: – Blast cleaning to visually clean steel – When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and from mill scale, rust, paint coatings and foreign matter. It shall have a uniform metallic colour.

blast cleaning steel components

Surface preparation by hand and power tool cleaning, such as scraping, wire brushing, machine brushing and grinding, is designated by the letters “St”

St2: Thorough hand and power tool cleaning – When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and from poorly adhering mill scale, rust, paint coatings and foreign matter.

St3: Very thorough hand and power tool cleaning – As for St2, but the surface shall be treated much more thoroughly to give a metallic sheen arising from the metallic substrate.

The Right Surface Treatment For Your Project

We offer a bespoke steel surface preparation service based on the starting condition of your steel surface and the required preparation grade. We use a variety of tools to achieve these results in the fastest and most cost-effective way, including purpose-built blast rooms and mobile blast units. Surface treatment can take place either in-house at our facility in Bradford, or on-site if required.

To discuss your project or find out more about our methods, please contact us on 01274 721188, or send an email to sales@kuegroup.com. You can also click here to request a quote online.

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