Identifying Metal Defects in Your Building

October 15, 2018 Defects inspection

Metals are widely used materials in buildings and construction. Thanks to their unique intrinsic properties they are often the preferred choice for roofing, heating systems, windows, cladding, and other structures and reinforcements in buildings. From old and historical buildings to new and modern architecture, the integrity of buildings relies on metals.

However, not all of these properties are beneficial in buildings and construction. Metals and alloys, just like other construction materials, may contain imperfections in their structure. These metal faults impair the chemical, mechanical, and electrical properties of these materials, such as electrical conductivity, magnetic permeability, strength, density, and plasticity.

Metal faults range from defects on the atomic scale, to coarser macroscopic defects you can see with the naked eye. They likewise vary in terms of the location, nature, and origin. In this article, we will look into different metal faults to know what to watch out for, to keep your building structure strong and sturdy.

Metal faults in terms of location

Metal defects can be classified based on where they occur. Specifically, metal defects may be local, distributed in limited, specific zones, or distributed throughout the entire surface of the metal. It is important to be aware of where a defect occurs, so that we can replace or repair the metal as needed.

1. Localised metal defects

Some metal defects are confined to a specific, limited area. They may be a point, a plane, or in three-dimensional, and may occur at the surface of the metal, or be deep inside it. They come in various forms, from pores, cavities, and cracks to ply separations, flakes, forging defects, and laps. Most of these defects are mechanical in nature. Certain physical and environmental factors have contributed to wearing down of the metal. If the wear isn’t evenly spread, local defects will occur.

Because the metal defects are localised, they are often harder to identify and inspect. However, they can be easier to repair and replace, without the need to repair or replace other unaffected structures.

2. Metal defects distributed in limited zones

Most of these defects are caused by chemical processes that affect the metal. One particular example is the damage brought by corrosion. A specific area of the metal structure exposed to oxidative agents will be highly prone to corrosion. Other examples include exposure to various liquids or temperature variations.

In contrast to localised metal faults, these distributed defects are easier to spot. However, because a larger portion of the metal structure is affected, they are harder to repair and replace.

3. Metal defects distributed throughout the entire surface

In some cases, metal defects may be distributed across the entire metal surface. These are commonly caused by problems in the production and construction of the metal structure. An example would be an issue with the chemical composition of the metals. This can create a material that has a weaker and poorer quality throughout the entire metal structure. In these cases, total replacement of the weak metal is necessary.

Metal faults in terms of nature and origin

Metal defects can also be classified on how and why they occurs. These defects are formed due to a number of causes, which include during smelting of the metal, during treatment, and as it wears down through time. Knowing how these metal faults were created often points to the process or situation that caused the defect. This way, the faulty process or unwanted situation can be corrected accordingly.

1. Defects formed during the smelting of the metal

In metal smelting, metal ores are melted and fused together. In this process, gaseous particles may be dissolved in the molten state of the metal. As the metal cools and solidifies, these dissolved gases are trapped inside, creating hollow spaces inside. These pores and cavities create a weaker integrity to the newly-formed metal structure.

Aside from gases, other non-metallic particles may be included in the molten state of the metal which may also affect its integrity. These particles are called inclusions. They may be indigenous, which means they are other by-products of the chemical reaction and are thus normal to be included in the molten mixture. They do not often place serious threat to the structure of the metal, but may be harmful if they are concentrated in one place. Exogenous inclusions, on the other hand, are larger, foreign substances introduced during the molten state which greatly affect the metal’s structure.

In general, these pores, cavities, and inclusions make the metal structure less dense than it otherwise would be. This means that metal structures with these defects may be  lighter than other similar metal structures.

2. Defects formed during treatment

Metal will often undergo treatment to alter its properties specific for a task. Some examples of these treatments are annealing and quenching. In annealing, the metal is cooled slowly after being heated to make it softer and easier to cut and sand. The opposite goes for quenching, in which the metal is cooled immediately after being heated to make it harder.

In these processes, however, defects are also likely to occur. For instance, in quenching, the rapid change in temperature may cause the metal to crack and deform a little.

3. Defects because of wearing of metals

Metals, as with other materials, wear through time. There are a lot of factors that cause the wearing of these particles. Physical wearing of metals occurs because of the repetitive or continuous effort it provides for the building. Chemical wearing of metals occurs because of oxidative agents such as water droplets corroding the metal.

Too technical? Don’t worry, Exceptional Building Inspections is here for you.

Many buildings rely on the strength and stability of metal. With routine building inspections of your property, the structural integrity of your building will be maximised.

At Exceptional Building Inspections, we offer Defect Inspection and Report services to make sure that there are no hidden defects in your property. Our services offer comprehensive reports for your needs which, of course, include inspection for metal faults. Contact us to book for an inspection today.

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