What is Corrosion?
Corrosion is often used in everyday life. It means people with corrosion, abrasion, corrosion, rusting, calcification and similar conditions in daily life. More technically, corrosion means that metal materials wear under the conditions of weather and humidity for electrical, chemical or mechanical reasons, and many metals undergo such corrosion.
Corrosion is a situation in which metal materials undergo electrochemical and chemical reactions and changes in their physical, chemical and mechanical properties under the influence of their environment. Corrosion occurs in several ways. For example, chemical corrosion is the state of oxidation of metals and alloys in the presence of gases. This is called dry corrosion. Decomposition of metals and alloys in humid environments is defined as electrochemical or wet corrosion. In nature, all metals except gold and platinum are oxidized. Removal of oxidized metals from oxides is a challenging process.
In short, the chemical, physical and mechanical properties of metals or their alloys exhibit undesirable changes, that is, damage to these materials is called corrosion. In other words, both the deterioration of these materials, for example the oxidation, as well as the damage of these materials is called corrosion. The rate of corrosion of metals or their alloys in different environments varies depending on the size of surface areas and time.
Now, let's see why corrosion is so important. First of all, all metal structures undergo more or less corrosion in the natural environment. Even stainless steel, brass, bronze, zinc and aluminum materials are very slow, but they experience corrosion.
Today, iron and steel are widely used in terms of both physical properties and costs. However, if these metals are not properly protected, their structural corrosion progresses very quickly. Therefore, it is particularly important that these metals be susceptible to corrosion. It is estimated that the loss of steel in the US due to corrosion is around $ 70 billion annually. Therefore, the protection of iron and steel against corrosion is of great importance.
What is Cathodic Protection?
Corrosion is a serious hazard, especially for metal materials that are underground or in water, for example pipes. Different protection methods have been developed in order to prevent corrosion of the material in which these pipes are made. One of these methods is cathodic protection. In order to prevent corrosion, this method of protection is called cathodic protection by placing a more active metal under the soil or near the pipes in wet environments.
Cathodic protection method is mostly applied in underground metal flooring area. In this method, an electrochemical cell constituting the metal structure to be protected is brought into a cathodic state and anoic reactions running on the metal are prevented.
The cathodic protection method was first applied during the 1930 years, but much progress has been made today. Due to the advancement of technology, new high-performance vehicles have emerged and cathodic protection has become both an economic and effective method of combating corrosion.
Today, cathodic protection is applied in two ways: external current source and galvanic anode. External flow-induced cathodic protection method is applied in areas with larger surface area. The negative end of the direct current obtained in this method is connected to the metal material to be protected and the positive end is connected to an auxiliary anode. In general, doped iron anodes are used in underground structures. In the cathodic protection method with galvanic anode, a galvanic battery is formed by connecting another metal material which has a more negative potential than the metal material in the underground which is to be protected. In this way, the metal structure to be protected is brought into cathode state. Galvanite anodes produce current like batteries. This method of protection is mostly preferred to protect the fuel and natural gas pipelines under the ground. LPG fuel tanks placed under ground are protected by galvanic anodes. In addition, galvanic anode protection method is used in the inner surface of hot water boilers, in fresh water storage tanks, in the water heater and in special structures in contact with all kinds of soil and water.
Cathodic Protection Measurements Inspection What are the basics?
In all cathodic protection methods, anodes are depleted over time and the expected cathodic protection is not achieved. If the external current protection method is applied, the outdoor units do not function correctly over time. For this reason, the long-term operation of cathodic protection systems as expected depends on regular measurements and controls. If faults are detected, necessary interventions should be made to ensure the continuous operation and correct operation of the protection system.
Cathodic protection measurements are performed by electrical engineers, electrical technicians or high technicians working in test and muyanene organizations in facilities of different sizes according to the requirements of the facilities.
In the annex of, Maintenance, Repairs and Periodic Inspections in of the Regulation on Health and Safety in the Use of Work Equipment issued by the Ministry of Labor and Social Security, this type of inspection and inspection is subject to the requirements of the relevant legislation and standards. at least once.
According to the regulation, the legal regulations that are taken into consideration in cathodic protection measurements are as follows:
- Regulation on Grounding in Electrical Installations
- Regulation on Electrical High Current Plants
- Electrical Internal Facilities Regulation
In addition, a few of the standards adopted in these studies are as follows:
- TS 5141 EN 12954 Cathodic protection - For embedded or submerged metallic structures - General principles and application for pipelines
- TS EN 13636 Cathodic construction of embedded metallic tanks and related piping system
- TS EN ISO 12696 Cathodic protection of steel in concrete
- TS EN 16222 Cathodic protection of ship hulls
- TS EN ISO 13174 Cathodic protection - for port facilities
- TS EN 16299 Cathodic protection of external surfaces on soil storage tank based on soil or base contact
