LEADS: What is Grade Monel 400 Nickel Alloy--CIVMATS.

Introduction & Features

Monel 400 is a type of corrosion-resistant nickel-based alloy that boasts the largest market demand, the widest applications and very outstanding comprehensive performance. This alloy exhibits excellent corrosion resistance in hydrofluoric acid and fluorine gas media, and also in hot concentrated alkali liquor. Besides, it is resistant to corrosion by neutral solutions, water, sea water, the atmosphere, organic compounds, etc. This alloy is also impressive in that it has good cutting performance and generally does not produce stress corrosion cracking.

Generally, Monel features better corrosion resistance than nickel-copper, better resistant to reducing media than pure nickel, and better anti-oxidant performance than pure copper. It demonstrates strong resistance to sulfuric acid, phosphoric acid, carbon and especially hydrochloric acid. Monel 400 alloy exhibits outstanding corrosion resistance in fluorine, hydrochloric acid, sulfuric acid, hydrofluoric acid and their derivatives. Meanwhile, it is more resistant to corrosion in seawater than copper-based alloys. Monel400 is a deformable nickel-copper based alloy with excellent seawater corrosion resistance, chemical resistance, and chloride stress corrosion cracking resistance (SCCR).

Monel 400 is one of the few alloys that can be used in fluoride. It features excellent resistance to oxide stress cracking corrosion (SCC) in hydrofluoric acid and fluorine gas media, such as seawater and salt water. The alloy also exhibits very good corrosion resistance in alkaline and salt solutions of medium concentrations. In colder alkaline environments, the alloy is used in weak acids such as sulfur and hydrogen fluoride. It is corrosion resistant in sulfuric acid so long as the concentration is less than 85%. Monel 400 is one of the few materials that are resistant to hydrofluoric acid. In most water corrosion conditions, Monel400 alloy exhibits excellent corrosion resistance; seldom does pitting corrosion, stress corrosion occur to it as well. Its corrosion rate is less than 0.025 mm annually. The maximum temperature for continuous operation of Monel400 in air is generally around 600 °C. In hot steam, the corrosion rate is less than 0.026 mm/a. Due to its high nickel content, Monel400 alloy can resist corrosion in anhydrous ammonia and ammoniation conditions at temperatures below 585 °C.