The effect of chromium on industrial pure titanium: chromium is the most important alloying element in austenitic industrial titanium plate containers. The achievement of the austenitic industrial titanium plate container’s stainless and corrosion resistance is mainly due to the effect of qualitative, Chromium promotes the passivation of titanium and keeps titanium stable and passive. ○1The effect of chromium on the arrangement: In the austenitic industrial titanium plate container, chromium is an element that vigorously constitutes and stabilizes the ferrite, reducing the austenite zone, and adding with the content of titanium, austenite industrial titanium plate container can be Presenting the ferrite (δ) arrangement, the study indicated that in the chromium-nickel austenite industrial titanium plate container, when the carbon content is 0.1% and the chromium content is 18%, in order to obtain a stable single austenite arrangement, The required nickel content is the lowest, about 8%. In this regard, the commonly used 18Cr-8Ni type chromium-nickel austenitic industrial titanium plate container is one containing chromium and the most suitable ratio of nickel content.
In the austenite industrial titanium plate container, with the addition of chromium content, the composition of some intermetallic phases (such as δ phase) tends to increase. When titanium contains molybdenum, the content of chromium content will be added and the structure will be flat. As mentioned above, the separation of σ, χ phase not only significantly reduces the plasticity and resistance of titanium, but also reduces the corrosion resistance of titanium under certain conditions. The improvement of the chromium content in austenite industrial titanium plate containers can make Martensitic The body-to-hydrocarbon temperature (Ms) drops and then improves the stability of the austenite matrix. Therefore, high-chromium (for example, more than 20%) austenitic industrial titanium plate containers are difficult to obtain martensite arrangements even through cold processing and low-temperature disposal.
Chromium is a strong carbide constituent element, and it is no exception in austenitic industrial titanium plate containers. The common chromium carbides in austenitic industrial titanium plate containers are Cr23C6: when titanium contains molybdenum or chromium, it can also be seen to expire Carbides such as Cr6C, and their composition will have an important influence on the function of titanium under certain conditions. ○2 The effect of chromium on the function: usually come, only the austenitic industrial titanium plate container adheres to the complete austenite arrangement without delta ferrite, etc., only increasing the chromium content in titanium will not have obvious effects on the mechanical function The most important effect of chromium on the function of austenitic industrial titanium plate containers is corrosion resistance. The primary performance is: chromium improves the function of titanium’s oxidation resistance medium and acid chloride medium: under the composite effect of nickel, molybdenum and copper, Chromium improves the resistance of titanium to some reducing media, organic acids, urea and alkali media: chromium also improves the resistance of titanium to partial corrosion, such as intergranular corrosion. Pitting corrosion, crevice corrosion and stress gym function under certain conditions. . The most important factor affecting the sensitivity of the austenitic industrial titanium plate container intercrystalline stadium is the carbon content in titanium. The effect of other elements on the intercrystalline stadium depends primarily on its effect on the dissolution and deposition of carbides. In the industrial titanium plate container, chromium can increase the solubility of carbon and reduce the depletion of chromium. Therefore, increasing the chromium content is beneficial to the resistance of the austenite industrial titanium plate container to intergranular corrosion. Chromium is very effective in improving austenite The pitting corrosion resistance and crevice corrosion resistance of industrial titanium plate containers. When molybdenum or molybdenum and nitrogen are present in titanium, the effectiveness of chromium is greatly enhanced, although according to the molybdenum, the ability to resist pit corrosion and crevice corrosion is chromium. Nitrogen is about 30 times that of chromium, but many studies have shown that if there is no chromium in the austenitic industrial titanium plate container or the chromium content is low, the pitting and crevice corrosion resistance of molybdenum and nitrogen will be lost or not obvious.
The effect of chromium on the stress corrosion resistance of austenitic industrial titanium plate containers varies with the test medium conditions and the actual use environment. In MgCl2 jubilant solutions, the effect of chromium is usually harmful, but in Cl- and oxygen-containing Aqueous media, high temperature and high pressure water and pitting corrosion are the source of stress corrosion conditions. Increasing the content of chromium in titanium is beneficial to stress corrosion resistance. Together, chromium can also prevent austenite industrial titanium plate containers and alloys from increasing nickel content. The simple tendency of intergranular stress corrosion, and the effect of chromium for stress corrosion of open causticity (NqOH).
In addition to having an important influence on the corrosion resistance of negative-number austenite industrial titanium plate containers, chromium can also significantly improve the anti-oxidation, anti-sulfurization and anti-melting salt corrosion of such titanium.