Excuse me, what corrosive agent is used for metallographic examination of Monel alloy?

Monel alloy, also known as nickel alloy, is an alloy based on metallic nickel and added with other elements such as copper, iron and manganese. Monel alloy has good corrosion resistance and is silvery white, which is suitable for edge line materials.

use

The structure of Monel 400 alloy is high-strength single-phase solid solution and single-phase austenite structure [2], which is a corrosion-resistant alloy with the largest dosage, the widest application and excellent comprehensive properties. The alloy has excellent corrosion resistance in hydrofluoric acid and fluorine gas medium, and also has excellent corrosion resistance to hot concentrated lye. At the same time, it is also resistant to the corrosion of neutral solution, water, seawater, atmosphere and organic compounds. An important feature of this alloy is that it generally does not produce stress corrosion cracks and has good cutting performance. The alloy is mainly used for valve stem, pump shaft and impeller, scraper of conveyor, oil well drill ring, elastic parts, valve gasket and so on.

corrosion resistance

The alloy has excellent corrosion resistance in fluorine gas, hydrochloric acid, sulfuric acid, hydrofluoric acid and its derivatives. Acid medium: M400 is corrosion-resistant in sulfuric acid with concentration less than 85%. M400 is one of the few important materials that can resist hydrofluoric acid. Water corrosion: In most cases of water corrosion, M400 alloy not only has excellent corrosion resistance, but also rarely finds pitting corrosion and stress corrosion, with the corrosion rate less than 0.025mm/a. High temperature corrosion: the highest temperature for M400 to work continuously in air is generally around 600℃, and the corrosion rate is less than 0.026mm/a in high temperature steam. Ammonia: Monel 400 alloy contains high nickel content, so it can resist the corrosion of anhydrous ammonia below 585℃ and ammoniation conditions.

The corrosion resistance of Monel K500 in general solution state is basically the same as that of Monel 400 alloy, so the corrosion resistance data of Monel 400 can be completely applied to Monel K500 alloy. This alloy has low corrosion rate and high strength in flowing seawater, and is especially suitable for manufacturing centrifugal pump shafts with seawater corrosion resistance.

product application

The nuclear industry is used to manufacture uranium refining and isotope separation equipment, seamless water pipes, steam pipes, seawater exchangers and evaporators in power plants, pumps and propellers of equipment used in sulfuric acid and hydrochloric acid environment, crude oil distillation, seawater, pumps and valves of equipment used in uranium refining and isotope separation, and hydrochloric acid production.

Monel K500(K500, NCu30-2- 1, UNS N05500) alloy not only has excellent mechanical properties such as high strength, corrosion resistance and non-magnetism, but also has the same corrosion resistance as Monel 400. It can be used as pump shaft material and is suitable for working in harsh geological mining conditions with high sulfur and high wax oil layer. Because the alloy has no plastic-brittle transition temperature, it is very suitable for all kinds of low temperature equipment. This alloy is mainly used for pump shaft and valve stem, conveyor scraper, oil well drill ring, elastic parts, valve gasket and so on. Suitable for petroleum, chemical shipbuilding, pharmacy, electronics and other departments.

Monel 400 alloy (UNS N04400 or MCu-28- 1.5- 1.8 or Ni68Cu28Fe) has good properties in seawater, chemical solvents, ammonia sulfur chloride, hydrogen chloride, various acidic media such as sulfuric acid, hydrofluoric acid, hydrochloric acid, phosphoric acid, organic acids, alkaline media, salts and molten salts.

Monel 400 alloy also has good mechanical properties, can be used in a wide temperature range from low temperature to high temperature, and has good weldability and medium-high strength.

Monel 400 is mainly used in the fields of chemistry, petrochemical industry and marine development. It can be used to manufacture various heat exchange equipment, boiler feed water heaters, petrochemical pipelines, containers, towers, tanks, valves, pumps, reaction vessels, shafts, etc.

Implementation standards: ASTM B 164 (bar and wire), ASTM B 564 (forging), ASTM B 127 (plate and strip) and ASTM B 165 (seamless pipe).

Monel 400 process

The alloy can be processed by traditional processing methods of iron-based materials. High-speed machines use water coolant when working overtime. Materials will shrink during processing, so pay attention to shrinkage allowance to ensure dimensional accuracy. Monel 400 welding

Monel 400 has good welding performance, and can adopt TIG and MIG methods, Monel or EniCu-7 welding wire and covered electrode; Or manual arc welding and submerged arc welding; Can be welded with carbon steel and low alloy steel.

mechanical properties

The alloy has no plastic-brittle transition temperature and is very suitable for manufacturing various low-temperature equipment. Welding can improve the strength of the alloy, but reduce the plasticity of the alloy. Therefore, in order to maintain high plasticity, Monel K500 alloy needs heat treatment after welding.

product application

This alloy has comprehensive properties of toughness and corrosion resistance, and is widely used in chemical industry. For example, it is used to manufacture heaters, heat exchangers, evaporators, distillers, distillation columns, fatty acid treatment condensers, rosin acid treatment equipment, chemical pumps, etc. Because the alloy also has high strength and good high-temperature oxidation resistance, it can also be used in heat treatment industry to manufacture various structural parts. In the nuclear power industry, the alloy has good corrosion resistance to high temperature and high pressure water, so it is also an important structural material for light water reactor nuclear power plants. Products include plates, rods, wires, belts and tubes.