What is the role of cr (chromium) in 42CrMo4 seamless steel pipe? Use chromium, the chemical symbol Cr, and the element is steel gray metal.
What is the role of cr (chromium) in 42CrMo4 seamless steel pipe?
The element name comes from the Greek, which originally meant “color” because chromium compounds all have color. Obtained with carbon reduction. The content of chromium in the crust is 0.01%, ranking 17th. There is no free chromium in nature, mainly in chromite. In the periodic table, it belongs to group ⅥB. The atomic number of chromium is 24, the atomic weight is 51.9961, and body-centered cubic crystals. The oxidation number is 6, 5, 4, 3, 2, 1, −1, −2, −4 and it is the hardest metal.
The decisive role of chromium in stainless steel gold
42CrMo4 seamless steel pipe is only one element that determines the nature of stainless steel. This is chromium. Each stainless steel contains a certain amount of chromium. To date, there is no chromium-free stainless steel. The fundamental reason why chromium becomes the main element that determines the performance of stainless steel,it’s the addition of chromium to steel, as an alloy element promotes the development,the internal contradictory movement in favor of resisting corrosion damage. This change can be explained from the following aspects: ① Chromium increases,the electrode potential of the iron-based solid solution ② Chromium absorbs iron electrons to passivate the iron, the passivation is due to the anode reaction is prevented,and the corrosion resistance of the metal and alloy is improved phenomenon. There are many theories that constitute the passivation of metals and alloys, mainly including thin film theory, adsorption theory and electron arrangement theory.
Chromium is used to make stainless steel, auto parts, tools, tapes and video tapes. Chrome plated on the metal can prevent rust, also known as dormitory, strong and beautiful.
Chromium can be used to make stainless steel. The color of red and emerald also comes from chromium. As the most important metal in modern technology, chromium-nickel steel fused in different percentages is ever-changing, and there are many kinds of incredible. The toxicity of chromium is related to its existing valence state. Hexavalent chromium is 100 times more toxic than trivalent chromium ,and it can be easily absorbed by the body and accumulated in the body. Trivalent chromium and hexavalent chromium can be converted into each other. Natural water does not contain chromium; the average concentration of chromium in seawater is 0.05ug / l; lower in drinking water. The sources of chromium pollution include sewage discharged from the processing of chromium-bearing ores, metal surface treatment, leather tanning, printing and dyeing, etc.
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