Corrosion-resistant Alloys

The Corrosion-resistant HASTELLOY® alloys are widely used by the chemical processing industries. The need for reliable performance leads to their acceptance and growth in the areas of energy, health and environmental, oil and gas, pharmaceutical and flue gas desulfurization industries. The attributes of HASTELLOY® alloys include high resistance to uniform attack, outstanding localized corrosion resistance, excellent stress corrosion cracking resistance, and ease of welding and fabrication.

B-3® alloy possesses outstanding resistance to non-oxidizing acids, such as hydrochloric acid and sulfuric acid. The advantages of B-3® alloy over previous B-family alloys are enhanced thermal stability and improved fabrication characteristics. A new alloy, HASTELLOY® HYBRID-BC1® alloy will handle stronger non-oxidizing acids than C-type alloys and will tolerate oxidizing impurities that B-type alloys will not.

The most versatile of the HASTELLOY® alloys are the “C-type” alloys. C-2000® alloy combines outstanding resistance to oxidizing media with superior resistance to non-oxidizing environments and represents a true performance breakthrough for chemical process equipment applications. C-22® alloy is particularly resistant to pitting and crevice corrosion; it has been used extensively to protect against the most corrosive FGD systems and the most sophisticated pharmaceutical reaction vessels.

G-30® alloy has been very successful as phosphoric acid heat exchanger tubing and for other process components in the fertilizer industry. G-35® alloy was designed as an improved version of G-30® alloy in these applications.  The high chromium content of both of these alloys make them the premier choices for strong oxidizing solutions and mixed acid pickling services.

Corrosion-resistant Alloys


HASTELLOY® B-3® alloy
HASTELLOY® B-3® alloy (UNS N10675) exhibits extremely high resistance to pure hydrochloric, hydrobromic, and sulfuric acids. Furthermore, it has greatly improved structural stability compared with previous B-type alloys, leading to fewer concerns during welding, fabrication, and service.
HASTELLOY® C-4 alloy
HASTELLOY® C-4 alloy (UNS N06455) is the most (microstructurally) stable of the widely used nickel-chromium-molybdenum materials, which are well known for their resistance to many aggressive chemicals, in particular hydrochloric acid, sulfuric acid, and chlorides. This stability means that the alloy can be welded without fear of sensitization, i.e. the nucleation and growth of deleterious, second phase precipitates in the grain boundaries of the weld heat-affected zone (HAZ).
HASTELLOY® C-22® alloy
HASTELLOY® C-22® alloy (UNS N06022) is one of the well-known and well-proven nickel-chromium-molybdenum materials, the chief attributes of which are resistance to both oxidizing and non-oxidizing chemicals, and protection from pitting, crevice attack, and stress corrosion cracking. Its high chromium content provides much higher resistance to oxidizing media than the family standard, C-276 alloy, and imparts exceptional resistance to chloride-induced pitting, an insidious and unpredictable form of attack, to which the stainless steels are prone.
HASTELLOY® C-22HS® alloy
HASTELLOY® C-22HS® alloy (N07022) is a versatile nickel-chromium-molybdenum alloy with excellent resistance to both oxidizing and reducing acids and which can be heat treated to obtain very high strength. Used in the oil & gas industry in bar, billet, tube and pipe product forms for applications that require very high strength and superior corrosion resistance. This alloy, especially suited for high-temperature, high-pressure wells, is capable of being produced at significantly higher strength levels than other nickel base alloys. It is qualified to NACE MRO175/ISO 15156 Level VII environment with 5 g/l elemental sulfur to 401ºF (205ºC) and modified NACE Level VII, 25% NaCl+1000 psi (7000 kPa) CO2 + 1000 psi (7000 kPa) H2S at 550ºF (288ºC) the highest level in the specification. The maximum hardness and yield strength covered is HRc43 and 205 ksi.
HASTELLOY® C-276 alloy
HASTELLOY® C-276 alloy (UNS N10276) is the first wrought, nickel-chromium-molybdenum material to alleviate concerns over welding (by virtue of extremely low carbon and silicon contents). As such, it was widely accepted in the chemical process and associated industries, and now has a 50-year-old track record of proven performance in a vast number of corrosive chemicals.
HASTELLOY® C-2000® alloy
HASTELLOY® C-2000® alloy (UNS N06200) is unique among the versatile nickel-chromium-molybdenum materials in having a deliberate copper addition. This provides greatly enhanced resistance to sulfuric acid. It also has a high chromium content, to maximize its resistance to oxidizing chemicals and process streams contaminated with ferric ions and dissolved oxygen.
HASTELLOY® G-30® alloy
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. Furthermore, G-30® alloy is less susceptible to chloride-induced stress corrosion cracking than the stainless steels.
HASTELLOY® G-35® alloy
HASTELLOY® G-35® alloy (UNS N06035) was developed to resist “fertilizer-grade” phosphoric acid (P2O5), which is used in the production of fertilizers. Tests in real-world solutions indicate that G-35® alloy is far superior to other metallic materials in this acid. It was also designed to resist localized attack in the presence of chlorides, since this can be a problem beneath deposits in evaporators used to concentrate “fertilizer-grade” phosphoric acid. Furthermore, G-35® alloy is much less susceptible to chloride-induced stress corrosion cracking than the stainless steels and nickel-chromium-iron alloys traditionally used in “fertilizer-grade” phosphoric acid.
HYBRID-BC1® alloy (UNS N10362) possesses much higher resistance to hydrochloric, hydrobromic, and sulfuric acids than the nickel-chromium-molybdenum (C-type) alloys, and can tolerate the presence of oxidizing species. The alloy also exhibits extremely high resistance to pitting and crevice corrosion.
HASTELLOY® N alloy (UNS N10003) has good resistance to aging and embrittlement and good fabricability. It has excellent resistance to hot fluoride salts in the temperature range of 1300°F to 1600°F (705°C-870°C).
ULTIMET® alloy
ULTIMET® alloy (UNS R31233) provides many of the corrosion characteristics of the nickel-based HASTELLOY G-type alloys and many of the wear characteristics of the cobalt-based STELLITE® alloys, in a single, highly weldable material. It excels under conditions conducive to galling and cavitation erosion.