What is hot-dip galvanizing?

The best and the logical solution to protect the steel materials against corrosion is coating it with the hot-dip galvanizing method.

Steel materials are corroded by loosing their physical, chemical, electrical and other characteristics affecting from the atmospheric conditions where they are. Those changes are summarized as “rusting”. Rusting is not only a visual defect but also a chemical reaction which negatively affects the metal. Also, as rust has about thirty times the volume of steel, rusty metal tends to destroy its environment. Therefore, the surface of steel structures should be treated with protective methods to get rid of the corrosive effects of the environment. Some examples of protective methods are painting and coating with plastics, nickel, chrome, copper and zinc. However, among all the methods, hot-dip galvanizing is the most reliable and long lasting coating method.
Hot-dip galvanizing features following advantages against other surface treatment methods:

• Buildup of a thick, penetrating and homogenous surface film even in critical spots like interiours, sharp edeges, cutting edges, bore surfaces, cavities, difficult to approach with other methods.
• All other methods are sensitive to surface damage like minor scratches as corrosion will start from these areas and will peel away the surface film. However, hot-dip galvanizing is resistant to scratching and has “self healing” properties. These properties can be summarized as “cathodic protection”.By the same token, hot-dip galvanized surfaces are resistant agains shocks like hammer blows.
• Zinc will form a metallurgical bond with the ferrous substrate and the alloy formed at the surface will increase the surface resistance to external influences.
• Within all surface treatment films, galvanizing is the most long lasting treatment and does not require any maintenance.
• Hot-dip galvanized surfaces display a certain visual appeal. Freshly galvanized surfaces show up a shiny and two dimensionally chyrstalline sturcture, later the surface assumes a homogenous dull gray appearance.
• Hot-dip galvanizing is an economical treatment of ferrous metals.

However, hot-dip galvanizing has also certain disadvantages:

• No repairs and modifications are possible with hot-dip galvanized structures. Any changes require the process to be repeated.
• Preferably, all members have to be galvanized separately, thus, an assembly has to be disassembled, galvanized and the reassembled and rebedded as required.
• Some structures, like tanks with small openings are not suitable for hot-dip galvanizing. The designer has to know beforehand, that the upcoming structure will be subjected to hot-dip galvanizing.
• The hot-dip galvanizing plant is an expensive and not very common investment, the logistics of the process may be difficult.

On most yachts chains and anchors are hot-dip galvanized. Specially classic yachts display hot dip galvanized anchor fittings, chain plates, fairleads, gooseneck and masttop fittings and a number of other structures.

YachtWORKS, recommends and performs hot-dip galvanizing according to TS-914 and DIN 50976 standards. Please contact us for quotes and for schedules.