Equipment and components in the petrochemical industry often face harsh working environments, including a variety of corrosive media, such as acids, alkalis, salts, etc. As a part of key equipment, the corrosion resistance of petrochemical forgings is of great significance to the operation life and safety of the whole equipment. In this paper, the corrosion resistance of petrochemical forgings will be deeply discussed in order to provide reference for related research and application.
The main corrosion form of petrochemical forgings
Homogeneous corrosion: homogeneous chemical or electrochemical reaction of the surface of a metal in a corrosive medium, resulting in gradual thinning of the metal.
Pitting: The rate of corrosion in local areas is much greater than in other areas, forming a pitting pit.
Gap corrosion: corrosion in small gaps between metal and metal or metal and non-metal due to differences in medium concentration.
Stress corrosion cracking: Brittle cracking occurs in metals under the combined action of tensile stress and corrosive media.
Factors affecting corrosion resistance of petrochemical forgings
Metal composition: The composition of a metal determines its inherent corrosion resistance. For example, the chromium element in stainless steel can form a dense oxide film with oxygen, thereby improving its corrosion resistance.
Microstructure: The microstructure characteristics of the metal such as grain size and phase composition will affect its corrosion resistance.
Processing and heat treatment processes: such as forging, welding, heat treatment and other processes may lead to changes in the microstructure of the metal, which affects its corrosion resistance.
Environmental factors: the type, concentration and temperature of corrosive media will affect the corrosion rate of metals.
Ways to improve corrosion resistance of petrochemical forgings
Reasonable selection of materials: according to the type and concentration of corrosive media in the working environment, select metal materials with excellent corrosion resistance.
Optimization of forging and heat treatment process: by controlling parameters such as forging temperature and cooling rate, the ideal microstructure and mechanical properties are obtained. Heat treatment processes such as solution treatment and aging treatment can further improve the corrosion resistance of metals.
Surface treatment: such as coating, coating, etc., can isolate the direct contact between corrosive media and metal, thereby improving the corrosion resistance of metal. Choosing the right coating material and process is the key.
Cathodic protection: Preventing electrochemical corrosion by applying a cathode current to a metal so that its potential is lower than that of its surroundings.
Regular inspection and maintenance: Regular corrosion detection of petrochemical forgings, timely detection and treatment of corrosion problems, can extend the service life of equipment.
Corrosion resistance of petrochemical forgings is one of the key factors to ensure the safety and longevity of equipment. It is an important way to improve the corrosion resistance of petrochemical forgings by deeply studying the corrosion forms and influencing factors and taking effective protective measures. In the future, with the emergence of new materials and new technologies, the research on corrosion resistance of petrochemical forgings will face more challenges and opportunities. Relevant enterprises and researchers need to constantly explore and innovate to adapt to changes in market demand and contribute to the sustainable development of the petrochemical industry.
