Characteristics of Hastelloy G30

Brief description of hastelloy G30

Designated as UNS N06030 or DIN 2.4603, Hastelloy G-30 is a nickel-chromium-iron material which has excellent resistance to phosphoric acid environment(wet process). Hastelloy G-30 is an improved version of nickel-chromium-iron-molybdenum-copper alloy G-3. With higher chromium, added cobalt and tungsten, the G-30 shows superior corrosion resistance over most other nickel and iron based alloys in commercial phosphoric acids as well as complex environments containing highly oxidizing acids.

Hastelloy G30 is corrosion resistant alloy with excellent corrosion resistance to oxidizing environments. Hastelloy G30 has been very successful as phosphoric acid heat exchanger tubing and for other process components in the fertilizer industry.The high chromium content of both of these Hastelloy G30 make them the premier choices for strong oxidizing solutions and mixed acid pickling services. It is also moderately resistant to chloride-induced localized attack, which can be a problem beneath deposits in the evaporators used to concentrate phosphoric acid. Furthermore, G-30 alloy is less susceptible to chloride-induced stress corrosion cracking than the stainless steels. Due to the high chromium content Hastelloy G30 is also very resistant to other oxidizing acids, such as nitric, and mixtures containing nitric acid. The appreciable amount of molybdenum and copper addition makes it moderately resistant to reducing acids, such as hydrochloric and sulfuric. Hastelloy G-30 is widely used in phosphoric, sulfuric, and nitric acid processing industries, nuclear piping, petrochemical and fertilizer industries.

Hastelloy G-30 resists the formation of grain boundary precipitates in the heat-affected zone, making it suitable in the as-welded condition. HASTELLOY G-30 is basically the same as other high alloys in regard to formability. It is generally stiffer than an austenitic. Because of its good ductility, cold working is relatively easy and is the preferred method of forming. The alloy is easily weldable using Gas-Tungsten Arc, Gas Metal Arc and shielded Metal Arc.

Chemical composition analysis of hastelloy G30

HASTELLOY G-30 alloy (UNS N06030) is a nickel-chromium-iron material highly resistant to “wet process” phosphoric acid (P2O5). P2O5 is one of the most important industrial chemicals, being the primary source of phosphorus for agrichemical fertilizers. G-30 alloy is also moderately resistant to chloride-induced localized attack, which can be a problem beneath deposits in the evaporators used to concentrate P2O5. Furthermore, G-30 alloy is less susceptible to chloride-induced stress corrosion cracking than the stainless steels. Hastelloy G-30 (UNS N06230) is an improved version of Ni-Cr-Fe-Mo-Cu alloy G-3. G-30 has a high content of chromium, cobalt and tungsten, and its corrosion resistance is better than most other nickel and iron-based alloys in commercial phosphoric acid and complex environments containing high oxidizing acids. The alloy’s resistance to the formation of grain boundary precipitates in the heat-affected zone makes it suitable for most chemical process applications under welding conditions.

The composition features of Hastelloy G-30 are mainly as follows:

Nickel-based alloy: The matrix of Hastelloy G-30 is a nickel-based alloy, which is one of the main reasons for its good oxidation resistance and corrosion resistance.

Chromium content: Hastelloy G-30 contains a certain amount of chromium, which is one of the main reasons for its good corrosion resistance.

Containing molybdenum and tungsten elements: Hastelloy G-30 contains a moderate amount of molybdenum and tungsten elements, which add to its high-temperature strength and oxidation resistance.

A small amount of elements: Hastelloy G-30 also contains small amounts of carbon, nitrogen, silicon, magnesium, and other elements, which have a certain improvement effect on the properties of the alloy. The complete chemical composition content of hastelloy G30 is shown in the table below:

Hastelloy G30 Physical Properties

Hastelloy G30 exhibits excellent physical properties such as high tensile strength, good ductility, and low thermal expansion. The density of this alloy is 8.22 g/cm³. It has a melting point of 1399°C and a boiling point of 3045°C. It also shows an excellent thermal conductivity of 8.62 W/m·K. Hastelloy G30 has exceptional mechanical properties that make it suitable for high-stress applications. The yield strength of this alloy is 416 MPa, whereas its ultimate tensile strength is 760 MPa.

Hardness: The hardness of Hastelloy G30 is dependent on its heat treatment. Generally, the alloy is supplied in the solution-annealed condition, which provides a hardness of around 130-160 HB. However, the hardness can reach up to 290 HB after precipitation hardening.

Heat Treatment: Hastelloy G30 can be heat-treated to achieve different strength levels. The solution-annealing treatment is the most common, which is carried out at a temperature range of 1070-1150°C. The alloy is then quenched in water or rapidly cooled in air. Another heat treatment process is the precipitation hardening method, which increases the hardness of the alloy.

Welding: Hastelloy G30 is weldable using many methods like TIG, MIG, and arc welding. The choice of welding method depends on the application and the desired mechanical properties. Care must be taken during welding to preserve the corrosion resistance of the alloy.

Corrosion Resistance: Hastelloy G30 is known for its exceptional corrosion resistance in oxidizing and reducing media. It resists attacks from hot and cold sulfuric acid solutions with concentrations up to 50%. It also resists nitric, acetic, and phosphoric acids, making it suitable for chemical processing industries. The alloy is also resistant to crevice and pitting corrosion in seawater and other chloride-containing environments.

Application areas for hastelloy G30

Hastelloy G30 is mainly used in the petrochemical industry such as oil well pipes, evaporators used in the production of wet phosphoric acid, nuclear fuel regeneration equipment in the nuclear industry, and pickling equipment in steel plants.  When drilling for oil and natural gas, in addition to drilling machinery and equipment, special pipes are also needed, namely drill strings, casings, tubing, etc., collectively referred to as “oil well pipes.” Oil well pipe accounts for about 40% of the total steel used in the oil and gas industry, and is an important part of oil and natural gas exploitation. According to the particularity of China’s oil and gas production environment, experts believe that ultra-high-strength tubing, high-strength tubing, tubing resistant to corrosion in acid environments, and special threaded tubing are high-performance tubing that China urgently needs today and in the future.

For a long time, China’s oil well pipe materials have mainly been 13Cr, 22Cr, 25Cr, 316 stainless steel and so on. These stainless steels have high strength and high Cr content. A dense cr2o3 passivation film is easily formed on the surface of the alloy, which can effectively resist the corrosion of CO, and with the increase of Cr content, it is resistant to CO2 corrosion. The ability to gradually increase oil. However, with the gradual discovery and exploitation of deeply buried high-acid oil and gas fields, the content of H2S, CO2, S, and C1 in the mining environment is high, and the commonly used stainless steel pipes can no longer meet the mining needs. Therefore, highly alloyed nickel-based corrosion-resistant alloys Hastelloy G30. G30 alloy is a nickel-based corrosion-resistant alloy with superior performance. The Ni-Cr-Fe system containing Mo and Cu has excellent resistance to oxidation, atmospheric corrosion and stress corrosion cracking. Due to the high content of Fe in the alloy, it has the characteristics of low cost compared to other nickel-based corrosion resistant alloys. The oil well pipe made of this alloy has excellent resistance to H2S, CO2, and Cl corrosion, and is the best choice for oil well pipe in sour gas fields. With the gradual development of sour oil and gas fields, the demand for nickel-based alloy oil well pipes continues to rise. Related products have not been fully mastered by a few foreign manufacturers of nickel-based corrosion-resistant alloy pipe manufacturing technology, which seriously threatens the country’s energy security. Therefore, it is imperative to localize nickel-based alloy pipes.