Wrought Iron is a specific type of iron, which literally means “worked iron”. It’s a traditional material worked by the blacksmith in the past. According to Lister, (1957) the word of “worked” refers to the method to produce the wrought iron. It was repeatedly hammered to its intended shape.
As stated by Young (2008), wrought iron is the purest form of metal consisting 99.85% true iron with less than 0.1% of Carbon. The lack of Carbon in the iron makes it resistance to corrosion for a longer period of time. The corrosion process is prolonged due to the lack of Carbon content.
Wrought iron has good properties strength because it is strong in both tension and compression. It is more fibrous in texture, more ductile and has a good resistance of corrosion compared to cast iron (Kent, 1888).
Even though the good prospect in structure, because of the nature of producing the wrought iron, the structural perspectives short of both cross section and length. Resulting short spanned beams. Hence the usage of wrought iron in structural elements restricted due to the small size in length.
But because of the high ductile (due to the less carbon content and the existence of 0.05% impurities in form of slag), wrought iron often used in production of hinges, chains, ornamental grille and gates, window decoration and house furniture.
Young (2008) points out that wrought iron has few weaknesses in varies section of production, installation, reaction and maintenance. The author also explains the description as below:
2.1 Metal Fatigue
In the nature of wrought iron production method, the over-repeatedly hammering process could cause metal fatigue in future. It weakened the bonded molecules of iron and the reaction with water and oxygen resulting the lost of structural integrity through out time.
2.2 Moisture and Corrosion
The existence of carbon, even in very small amount and the connection with oxygen and water can cause moisture and corrosion in long period. The wrought iron will become discoloration, condensation and slow rust.
2.3 Jointing Failure
The jointing made by varies method (welding, bolt) has different element composition. It creates chemical reaction towards multiple elements and cause jointing failure and ruins its structural integrity as a whole.
2.4 Construction Issues
Through out the time, additional loads and requirement added in any intervention on existing wrought iron element such as window frame. The new force will be added when replacing the new glass for the window and cause a distortion or even worse, the structural composition.
3.0 Method of diagnosing its failure
To analyze the current condition of wrought iron, few methods used to diagnose its failure
The symptoms of material failure can be observed through its discoloration, the change of shape, the unsymmetrical composition, and the change of color and any mark of dampness...