【Corrosion Technology Edition】Daily Question 20170717: What is high-temperature oxidative corrosion?
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To increase the popularity of the Corrosion Technology section, foster communication among users, and enable mutual progress and improvement, the 【One Question per Day】 activity has been launched. Reward rules: 3 wealth points for replying, 10 wealth points for correct answers. This topic is valid for two days; no scoring or rewards will be given after that. Term explanation: What is high-temperature oxidative corrosion? The high-temperature oxidation of metals begins with the chemical reaction between gas molecules and the metal surface to form an oxide film. Since no metal or alloy is immune to reaction with oxygen, it is the structure of the oxide film formed on the metal surface that determines whether that metal is resistant to oxidation or not. ============================= Event Promotion: Petrochemical Zone – “Creative Ideas for Energy Savings” event (the second phase is in full swing) http://bbs.hcbbs.com/thread-1666758-1-1.html (Source: Haichuan Chemical Industry Forum) 2017 Coal Chemical Industry Event – “My Technical Upgrades” http://bbs.hcbbs.com/thread-1786290-1-1.html (Source: Haichuan Chemical Industry Forum)
A type of metal corrosion that occurs at high temperatures when a metal reacts with oxygen to form oxides.
The process by which metals react with oxygen in the environment to form oxides
A type of metal corrosion that occurs at high temperatures when a metal reacts with oxygen to form oxides. Broadly defined, high-temperature oxidation includes sulfidation, halidation, nitridation, carburization, etc.
A type of metal corrosion that occurs when metal materials react with oxygen at high temperatures to form oxides
High-temperature corrosion is the degradation of metal materials caused by their reaction with environmental media at high temperatures. High-temperature corrosion is generally classified into three categories based on the state of the corrosive medium. (1) Corrosion in high-temperature gaseous media is commonly referred to as high-temperature oxidation, high-temperature gas corrosion, gas corrosion, or dry corrosion. (The steel industry is primarily affected by this type of corrosion.) (2) Corrosion in high-temperature liquid media, also known as high-temperature liquid corrosion or thermal corrosion, includes corrosion caused by high-temperature liquid metals and molten salts. (3) Corrosion of high-temperature solid media, also known as high-temperature abrasion or erosion.
High-temperature corrosion is the degradation of metal materials caused by their reaction with environmental media at high temperatures. High-temperature corrosion is generally classified into three categories based on the state of the corrosive medium. (1) Corrosion in high-temperature gaseous media is commonly referred to as high-temperature oxidation, high-temperature gas corrosion, gas corrosion, or dry corrosion. (The steel industry is primarily affected by this type of corrosion.) (2) Corrosion in high-temperature liquid media, also known as high-temperature liquid corrosion or thermal corrosion, includes corrosion caused by high-temperature liquid metals and molten salts. (3) Corrosion of high-temperature solid media, also known as high-temperature abrasion or erosion.
High-temperature oxidation refers to a type of metal corrosion that occurs when a metal material reacts with oxygen at high temperatures to form oxides. Broadly defined, high-temperature oxidation includes sulfidation, halidation, nitridation, carburization, etc.
Warm corrosion, also known as ash corrosion, refers to the situation where the inner ash layer formed due to high-temperature ash accumulation contains a high amount of alkali metals. Through prolonged chemical reactions between these alkali metals and components such as iron and aluminum present in the fly ash, as well as sulfur oxides that diffuse in from the outside ash layer via the flue gases, compounds such as sulfates of alkali metals are formed. Alkali metal sulfate complexes in a molten or semi-molten state undergo intense oxidation reactions with the alloy steel of reheaters and superheaters, causing the wall thickness to decrease and stresses to increase; this leads to internal creep of the tube walls, further thinning them until damage occurs and the tube bursts.
Warm corrosion, also known as ash corrosion, refers to the situation where the inner ash layer formed due to high-temperature ash accumulation contains a high amount of alkali metals. Through prolonged chemical reactions between these alkali metals and components such as iron and aluminum present in the fly ash, as well as sulfur oxides that diffuse in from the outside ash layer via the flue gases, compounds such as sulfates of alkali metals are formed. Alkali metal sulfate complexes in a molten or semi-molten state undergo intense oxidation reactions with the alloy steel of reheaters and superheaters, causing the wall thickness to decrease and stresses to increase; this leads to internal creep of the tube walls, further thinning them until damage occurs and the tube bursts.
Warm corrosion, also known as ash corrosion, refers to the situation where the inner ash layer formed due to high-temperature ash accumulation contains a high amount of alkali metals. Through prolonged chemical reactions between these alkali metals and components such as iron and aluminum present in the fly ash, as well as sulfur oxides that diffuse in from the outside ash layer via the flue gases, compounds such as sulfates of alkali metals are formed. Alkali metal sulfate complexes in a molten or semi-molten state undergo intense oxidation reactions with the alloy steel of reheaters and superheaters, causing the wall thickness to decrease and stresses to increase; this leads to internal creep of the tube walls, further thinning them until damage occurs and the tube bursts.