Hot Dip Galvanising

The achievement of a quality hot dip galvanized coating, for general and architectural use, is dependent on many issues, some controllable and some not. This checklist addresses the issues that can be controlled by the designer and those controllable by the galvanizer.     LEAD TIMES In the case of large contracts, the galvanizer should […]

Staining and Discolouration of Galvanised Steel Galvanized steelwork can be subject to staining and discolouration which can sometimes be mistaken for failure of the coating and rusting of the base steel. There are numerous reasons why such staining may take place and there are summaries below. Surface Contamination One of the most common causes of

Distortion & Warping During Galvanising      In practice, cases of distortion during hot dip galvanizing are relatively infrequent. There are a number of important criteria that designers should keep in mind.   Causes   Distortion occurs due to the relief of locked-in stresses within a steel section or fabrication. At room temperature, the steel

Protecting Threads During Galvanising     When galvanizing a steel article, it may be desirable to prevent a coating from forming in certain areas which will have special functions such as: A threaded component on a fabrication Drilled holes Surfaces which will be subject to welding after galvanizing There are several different methods that may

The galvanized coating applied by immersion in a bath containing molten zinc not only provides a high level of corrosion protection but is also very robust, such that it will normally withstand handling and erection. However, the coating may occasionally be subject to small areas of mechanical damage typically as chips at edges or corners

Galvanizing of castings is covered by EN ISO 1461:2009. Hot dip galvanizing of cast iron provides excellent protection from corrosion and the coating is applied by immersion in molten zinc at 450°C forming a tough, adherent coating which is bonded to the base metal by series of zinc-iron alloy layers overlaid with free zinc.  

Welding Before and After Hot Dip Galvanizing     A proportion of steelwork that is hot dip galvanized is subject to fabrication by welding prior to dipping. The welding process can affect galvanizing in terms of coating quality, distortion and creating an increased potential for cracking in isolated instances. By taking suitable actions these issues

Dark, grey or light grey – it`s all galvanised. Protection is equal – and often better – with dark grey coatings than with light grey.   When rimmed or aluminium killed steels are hot dip galvanised, compact zinc-iron alloy layers are formed and covered by zinc, which has a light bluish grey metallic lustre. In

Hot dip galvanising is a process in which articles are immersed in various baths. Most hot dip galvanising is contracted out to specialist firms, which may also be responsible for the transport and handling of the material. Although bath sizes have increased over the years they can still be a limiting factor. Dimensions, weights and

Processes in the galvanising plant, such as degreasing, pickling, rinsing, fluxing and actual hot dip galvanising itself involve immersion in baths. It is important therefore that the liquid in the bath can reach into every corner and crevice – even with hollow components.   In got dip galvanising vessels and hollow fabrications are coated on