Corrosion protection of steel structures by hot dip galvanizing

Hot-dip galvanizing is one of the most widely used anti-corrosion processes for steel in the world.

In 2013, around 60% of the 13 million tonnes of zinc produced were used to galvanize steel, significantly extending its service life.

Galvanized steel can be found in all sectors of activity:

• building ;

• transport ;

• energy;

• street furniture ;

• household and industrial equipment...

The French market, with 600,000 to 800,000 tonnes of hot-dip galvanized steel depending on the year, is Europe's 5th largest galvanizing market; the German market is 1 ^er with over 2 million tonnes of galvanized steel every year.

The term "hot-dip galvanizing" covers two distinct industrial processes:

• Continuous hot-dip galvanizing (of steel coils or wires);

• custom hot-dip galvanizing (of finished parts) to standard NF EN ISO 1461 .

Since metal structures are "custom" or "dip" galvanized, we focus here on this single process and its implementation, with the aim of providing users and specifiers with the means to achieve optimum quality.

We begin with a brief overview of the various processes for protecting steel with zinc, followed by a detailed description of the hot-dip galvanizing process, its principle and application.

We then go on to discuss the design, manufacturing, assembly and inspection details required for successful hot-dip galvanizing of steel structures.