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Several Local Corrosion Characteristics Of Titanium Materials

Aug. 30, 2019

Here is a Titanium Pipe Astm B861 Factory talking about several local corrosion characteristics of titanium materials.

1. Crevice Corrosion.

Titanium Plate has particularly strong crevice corrosion resistance, and crevice corrosion occurs only in a few chemical media. The crevice corrosion of titanium is closely related to temperature, chloride concentration, pH, and the size of the gap. According to relevant information, crevice corrosion is likely to occur when the temperature of wet chlorine gas is above 85 °C. For example, some plants use a packed tower to cool directly before the cooler to reduce the temperature of the wet chlorine gas to 65-70 ° C, and then enter the titanium cooler to improve the resistance to crevice corrosion, and the effect is also remarkable. Practice has proved that lowering the temperature is one of the effective methods to prevent crevice corrosion. Titanium crevice corrosion has also occurred in high temperature sodium chloride solution. In short, for parts and components that are prone to crevice corrosion, such as sealing surfaces, expansion joints between tube sheets and tubes, plate heat exchangers, contact parts between trays and towers, and fasteners in towers, Ti-0.2Pd and other titanium should be used. Alloys should be designed to avoid gaps and stagnant areas. For example, the fasteners in the tower should be as far as possible without bolting. The pipe plate and the pipe adopt the expansion joint and the sealing welding structure is better than the simple expansion joint. For the flange sealing surface, the asbestos pad should not be used, and the PTFE film should be used as the asbestos pad.

Titanium Plate

Titanium Plate

2. Stress corrosion.

In addition to a few kinds of media, industrial pure titanium is excellent in stress corrosion resistance, and damage to titanium equipment due to stress corrosion is rare. Industrial blunt titanium is only used in fuming nitric acid, some methanol solution or some hydrochloric acid solution, high temperature hypochlorite, molten salt at 300-450 ° C or NaCl-containing atmosphere, carbon disulfide, n-hexane and dry chlorine. Stress corrosion occurs. Titanium tends to increase in stress corrosion cracking with increasing NO2 content and water content in nitric acid. Titanium has a tendency to maximize stress corrosion in anhydrous nitric acid containing 20% free NO2. When concentrated nitric acid contains more than 6.0% NO2 and less than 0.7% H2O, even at room temperature, industrial pure titanium may undergo stress corrosion cracking. China has experienced severe stress corrosion and explosion when using titanium equipment in 98% concentrated nitric acid. Industrial pure titanium has the sensitivity of stress corrosion cracking in 10% hydrochloric acid solution, and stress corrosion occurs in titanium containing 0.4% hydrochloric acid plus methanol solution.

In summary, titanium has strong corrosion resistance in acid and alkali. It can form an oxide film in acid and alkali, but it is also conditional. I hope it will help you when using our materials.

We have Titanium Plate Gr2. If you need any information about it, feel free to let us know.

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