-- Introduce

Hastelloy is a nickel based corrosion-resistant alloy, mainly divided into two categories: nickel chromium alloy and nickel chromium molybdenum alloy. Hastelloy alloy has good corrosion resistance and thermal stability, and is commonly used in aviation, chemical fields, and other fields.

Hastelloy alloy is a general term for the commercial grades of nickel based corrosion-resistant alloys produced by Hastelloy International in the United States. Including nickel molybdenum Hastelloy B-2, nickel chromium molybdenum Hastelloy C-4, etc.

-- Hastelloy grades include the following:

HASTELLOY B-2 nickel molybdenum alloy has excellent corrosion resistance in reducing environments. The upgraded version of HASTELLOY B-3 B-2 has excellent corrosion resistance to hydrochloric acid at any temperature and concentration.

HASTELLOY C-4 has good thermal stability, good toughness and corrosion resistance at 650-1040 degrees Celsius.

HASTELLOY C-22 has better resistance to uniform corrosion in oxidizing media than C-4 and C-276, and excellent resistance to local corrosion. HASTELLOY C-276 has good resistance to oxidative and moderate reducing corrosion, and excellent stress corrosion resistance. HASTELLOY C-2000 is the most comprehensive corrosion-resistant alloy with excellent resistance to uniform corrosion in both oxidation and reduction environments.

The upgraded product of HASTELLOY G-35 G-30 has better corrosion resistance and thermal stability. HASTELLOY G-30 nickel based alloy with high chromium content exhibits excellent performance in phosphoric acid and other strong oxidizing mixed acid media.

HASTELLOY X combines the characteristics of high strength, oxidation resistance, and ease of processing. Each of the above grades has specific chemical composition, mechanical properties, and each has its own strengths. It cannot be generalized to say what characteristics Hastelloy alloy has.

-- Use

Hastelloy alloy plates are suitable for various chemical industries containing oxidizing and reducing media. The high content of molybdenum and chromium makes the alloy resistant to chloride ion corrosion, while tungsten further improves its corrosion resistance. At the same time, C-276 Hastelloy tube is one of the few materials that is resistant to corrosion from damp chlorine gas, hypochlorite, and chlorine dioxide solutions, and has significant corrosion resistance to high concentration chloride solutions such as iron chloride and copper chloride.

Application fields: heat exchangers, corrugated pipe compensators, chemical equipment, flue gas desulfurization and denitrification, papermaking industry, aerospace applications, acidic environments.

-- Characteristic

In both oxidation and reduction atmospheres, it exhibits excellent corrosion resistance to most corrosive media.

Has excellent resistance to pitting corrosion, crevice corrosion, and stress cracking corrosion.

-- Chemical composition

-- Mechanical property

1. Hastelloy alloy comes from Hastelloy and originated from Hastelloy B alloy, which is applied to rocket nozzles in aircraft; Later, Hastelloy C alloy was applied and promoted in chemical industry, petrochemical industry, Nuclear Energy industry and pharmaceutical industry; Subsequently, Hastelloy X alloy exhibited excellent high-temperature resistance, accompanied by the rapid growth of the jet aircraft industry.

2. The early Hastelloy B, Hastelloy C, and Hastelloy X alloys need solution treatment after welding, otherwise, the corrosion resistance of the welded Heat-affected zone will be greatly reduced; So the above alloys have gradually been improved or no longer used;

3. The key factor affecting the welding performance of the above materials is the C and Si content. Due to the emergence and improvement of refining technology, the welding problems of Hastelloy have been improved, resulting in many improved Hastelloy B series and Hastelloy C series alloys being promoted and used. Unfortunately, many Hastelloy production and promotion units have instead replaced the previous Hastelloy with the later improved Hastelloy, not only without reducing the C and Si content, Instead, it returned to the previous high Si and high C content; The promotion of the special steel industry has a long way to go.

4. The Hastelloy B series alloy with resistance to reducing media has been improved on the basis of the Hastelloy B grade. The focus of the improvement includes improving the performance of the welding area with extremely low C and Si content, further alloying ideas, and the application of pure purification steel ideas. As a result, the Hastelloy B series has developed Hastelloy B-2, Hastelloy B-3, and Hastelloy B-4 alloys; Among them, Hastelloy B-2 alloy solves the performance problem of the welding area to a certain extent; Hastelloy B-3 solves the problem that Hastelloy B-2 is easy to precipitate Ni Mo precipitation hardening, and greatly improves the hot working and cold working properties.

5. In the process of improving the Hastelloy B series of materials for reducing environmental applications; The Hastelloy C series alloy in the redox composite environment is also continuously improving. Among them, Hastelloy C276 alloy has improved the performance of the welding area to some extent due to lower C and Si content, but it is still not satisfactory, and the processing performance has not been significantly improved; And the Hastelloy C22 material has completely solved the corrosion resistance and processing performance problems in the welding area, mainly on the basis of not increasing the material cost. Therefore, Hastelloy C22 material is the most cost-effective material in the Hastelloy C series, and will be applied in larger quantities in the future; The newly developed Hastelloy C2000 material has added Cu to the alloy, which expands the corrosion ability of Hastelloy C alloy in reducing environments, providing possibilities for safer use and higher equipment life requirements, as well as for new process trial production occasions.

Hastelloy is an ultra-low carbon type, Ni, Mo, Cr series nickel based, corrosion resistant, high temperature resistant material. Hastelloy is used in harsh industrial environments such as chemurgy, nuclear facilities, biological pharmaceuticals, etc. because of its excellent high temperature resistance, oxidation resistance, corrosion resistance in weld affected areas, good long-term thermal stability and processability. It also has excellent corrosion resistance, uniform corrosion resistance, and intergranular corrosion resistance in the medium of wet oxygen, sulfuric acid, acetic acid, formic acid, and strong oxidizing salts. Therefore, it is widely used in the chemical industry. The conductivity and thermal conductivity of Hastelloy gold are much lower than those of low-carbon steel, while the resistivity and expansion rate are much higher than low-carbon steel. The molten pool has poor fluidity, poor wettability, low penetration, and shallow melting depth.

-- Classify

Hastelloy alloys are mainly divided into three series: B, C, and G, which are mainly used in strong corrosive media such as iron based Cr Ni or Cr Ni Mo stainless steel and non-metallic materials that cannot be used.

In order to improve the corrosion resistance and cold and hot working properties of Hastelloy, Hastelloy has made three major improvements. The development process is as follows:

B series: B → B-2 (00Ni70Mo28) → B-3.

C series: C → C-276 (00Cr16Mo16W4) → C-4 (00Cr16Mo16) → C-22 (00Cr22Mo13W3) → C-2000 (00Cr20Mo16).

G series: G → G-3 (00Cr22Ni48Mo7Cu) → G-30 (00Cr30Ni48Mo7Cu).

The most widely used materials are the second generation materials N10665 (B-2), N10276 (C-276), N06022 (C-22), N06455 (C-4), and N06985 (G-3).

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