Nickel-based super alloy: Hastelloy B2 (UNS N10665)

What is Hastelloy B2?

Hastelloy B2 (UNS N10665/W.Nr. 2.4617/Alloy B2) is a solid solution strengthened nickel-molybdenum alloy with low addition of carbon, silicon & iron. It has good resistance to hydrogen chloride, sulfuric acid and phosphoric acids and has excellent resistance to stress corrosion cracking and pitting corrosion at elevated temperatures. The significantly low carbon content makes Hastelloy B2 less susceptible to decreased corrosion resistance in the weld zone, in the as-welded condition. It can be used in reducing chemical environments and chemical processing industry. However, Hastelloy B2 should not be used at temperatures between 1000°F and 1600°F nor be used in oxidizing media.
Hastelloy B-2 (UNS N10665) is a solid solution strengthened, nickel-molybdenum alloy, typically used in extreme reducing conditions. Hastelloy B-2 has significantly lower carbon, silicon and iron compared to its’ predecessor, Hastelloy B (UNS N10001), making the alloy less susceptible to decreased corrosion resistance in the weld zone, in the as-welded condition. Controlling other alloying elements such as iron and chromium solved other issues concerning fabricability. Stringent chemistry control along with years of development has resulted in the alloy used today, both in Hastelloy B-2 and Hastelloy B-3, Hastelloy B-2 with restricted chemistry can be used in the welded condition and is less susceptible to SCC under many conditions. As always, care must taken in selecting the right alloy for the desired application.
Hastelloy B-2 should not be used at temperatures between 1000°F and 1600°F as the alloy forms secondary phases that could decrease the ductility of the material.

20200902224436 49046 - Nickel-based super alloy: Hastelloy B2 (UNS N10665)

Hastelloy B2 Forged Elbow 1″ 3000#

Types of Hastelloy

  • Hastelloy B-2 nickel molybdenum alloy has excellent corrosion resistance in reducing environment
  • The upgraded version of Hastelloy B-3: B-2 has excellent corrosion resistance to hydrochloric acid at any temperature and concentration
  • Hastelloy C-4: good thermal stability, good toughness and corrosion resistance at 650-1040 ℃
  • Hastelloy C-22: has better uniform corrosion resistance than C-4 and C-276 in oxidizing medium and excellent local corrosion resistance
  • Hastelloy C-276: good resistance to oxidizing and moderate reducing corrosion, excellent resistance to stress corrosion
  • Hastelloy C-2000: the most comprehensive corrosion resistant alloy with excellent uniform corrosion resistance in oxidation and reduction environments
  • Hastelloy G-35: the upgraded product of G-30 has better corrosion resistance and thermal stability, and has excellent performance in phosphoric acid and other strong oxidizing mixed acid media with high chromium content
  • Hastelloy X: combined with the characteristics of high strength, oxidation resistance and easy processing, each of the above grades has its own specific chemical composition, mechanical properties and strong points, so we can’t generalize the characteristics of Hastelloy

Hastelloy alloy is mainly divided into three series B, C and G. it is mainly used in iron-based Cr Ni or Cr Ni Mo stainless steel, non-metallic materials and other occasions with strong corrosive medium.
In order to improve the corrosion resistance and cold and hot working properties of Hastelloy, three major improvements have been made to Hastelloy:

  • Series B: B → B-2 (00ni70mo28) → B-3
  • Series C: 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 N10665 (B-2), N10276 (C-276), N06022 (C-22), N06455 (C-4) and N06985 (G-3)

Chemical Composition of Hastelloy B2 (UNS N10665)























Equivalent Grades of Hastelloy B2 (UNS N10665)

Hastelloy B-2
Nimofer 6928
NS3202 Hastelloy B-2 N10665 NiMo28 2.4617 NA44

Physical Properties of Hastelloy B2 (UNS N10665)


Melting Point 


Coefficient of
thermal expansion

Elastic modulus

Hardness (Brinell)/HRC







Mechanical Properties of Hastelloy B2 (UNS N10665)


 Tensile strength

Yield strength


Round bar








Welded pipe




Seamless tube




  • 1. Hastelloy alloy comes from Hastelloy, starting from Hastelloy alloy B, which is used in rocket nozzle of aircraft; then Hastelloy C alloy has been applied and promoted in chemical industry, petrochemical industry, nuclear energy industry and pharmaceutical industry; then Hastelloy x alloy shows excellent high temperature resistance, with the rapid growth of jet aircraft industry.
  • 2. Because the early Hastelloy B, Hastelloy C and Hastelloy x need solution treatment after welding, otherwise, the corrosion resistance of HAZ will be greatly reduced, so the above alloys have been gradually improved or no longer used;
  • 3. The key reason affecting the welding properties of the above materials is C, Because of the appearance and improvement of refining technology, the welding problems of Hastelloy have been improved, so there are a lot of improved Hastelloy B series and Hastelloy C series alloys which are being popularized and used. It is a pity that many Hastelloy production and promotion units have instead replaced the Hastelloy alloy in the earlier stage instead of the later improved Hastelloy alloy, which does not reduce the C content, The content of Si, on the contrary, returns to the former high Si and high C content.
  • 4. Hastelloy B series alloys with reducing medium resistance are improved on the basis of Hastelloy B grade. The key points of improvement include extremely low C and Si content, improvement of welding area performance, further alloying ideas, application of pure purification of molten steel, etc. thus, Hastelloy B-2, Hastelloy B-3 appear in Hastelloy B series, Hastelloy B-4 alloy, of which Hastelloy B-2 solves the problem of welding zone performance to a certain extent; Hastelloy B-3 solves the defect of Hastelloy B-2 easy precipitation of Ni Mo precipitation hardening, which greatly improves the hot working and cold working properties.
  • 5. In the process of improving Hastelloy B series materials for reductive environment, the Hastelloy C series alloys in the redox composite environment are also continuously improved, among which Hastelloy C276 alloy has lower C value, Si content can improve the performance of welding area to a certain extent, but it is still not satisfied, and the processing performance has not been improved; and Hastelloy C22 material has completely solved the corrosion resistance problem of welding area, and the processing performance problem is mainly solved on the basis of not increasing the material cost. Therefore, Hastelloy C22 material is the most cost-effective material in Hastelloy C series However, the newly developed Hastelloy C2000 material has been added with Cu in the alloy, which expands the corrosion ability of Hastelloy C alloy in reducing environment, and provides the possibility for safer use, higher equipment life requirements and new process trial production occasions.
  • Hastelloy is an ultra-low carbon, Ni, Mo, CR series of nickel based, corrosion-resistant and high-temperature resistant materials. Because of its excellent high-temperature resistance, oxidation resistance, corrosion resistance of weld affected zone, good long-term thermal stability and processability, Hastelloy has been applied in harsh industrial environment such as agricultural and chemical industry, nuclear facilities, biological pharmacy, etc. It also has excellent corrosion resistance, uniform corrosion resistance and intergranular corrosion resistance in the media of wet oxygen, sulfite, acetic acid, formic acid and strong oxide salt. Therefore, it is widely used in chemical industry. The conductivity and thermal conductivity of Hastelloy are much lower than that of low carbon steel, while the resistivity and expansion rate are much higher than that of low carbon steel. The molten pool has poor fluidity, poor wettability and penetration Small, shallow penetration.

Product Forms and Standards of Hastelloy B2

Rod, Bar, Wire, Forgings


Plate, Sheet, Strip ASTM B333, ASME SB333
Pipe, Tube ASTM B622, ASTM B619, ASTM B775, ASME SB622, ASME SB619, ASME SB775
Others ASTM B366, ASTM B564, ASTM B462, ASME SB366, ASME SB564, ASME SB462

*The mechanical properties of Hastelloy B2 vary in different forms or heat treatment conditions.

Annealing of Hastelloy B2

  • Anneal following extensive work hardening due to cold working by 1950 F soak followed by rapid quench. Note that bright finish parts must be solution annealed and rapid cooled in an inert (argon gas) or reducing (hydrogen) atmosphere to prevent surface oxidation during heating and cooling.

Heat Treatment of Hastelloy B2

  • Solution treated at 1950 F and rapid quenched. This is the normal condition in which the product forms are furnished and used. Bright annealed product forms (sheet & strip) are solution treated at 2100 F and then cooled in a hydrogen atmosphere to prevent oxidation of the bright surface.

Application areas of nickel-based alloy Hastelloy B2 (UNS N10665):

20200902225659 70005 - Nickel-based super alloy: Hastelloy B2 (UNS N10665)

An Alloy B2 90DEG Elbow 4″ SCH80S extruded from the UNS N10665 seamless pipe.

Hastelloy B2 (UNS N10665) is widely used in the chemical, petrochemical, energy manufacturing and pollution control related processing and equipment , especially in the processes dealing with various acids (sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid and so on. Some of the more common uses of Hastelloy B2 include:

  • Wire wound resistors.
  • Bimetal contacts.
  • Electric and electronic applications.
  • Marine engineering.
  • Chemical and hydrocarbon processing equipment.
  • Gasoline and freshwater tanks.
  • Crude petroleum stills.
  • De-aerating heaters.
  • Boiler feed water heaters and other heat exchangers.
  • Pumps, shafts and fasteners.
  • Industrial heat exchangers.
  • Chlorinated solvents.
  • Crude oil distillation towers.
  • Meter and valve parts.
  • Screw machine products.
  • Oil refinery piping.
  • Heat exchangers.
  • Nuclear fuel production.
  • Generator tubing.
  • High temperature heating coils.
  • Crude oil transfer piping.
  • Propeller and pump shafts.
  • Piping system.
  • Heat exchange tubes.
  • Pipe fittings.
  • Flanges.
  • Valves.

Variety specifications and supply status of Nickel-based super alloy: Hastelloy B2 (UNS N10665):

Variety classification:

Yaang Pipe Industry can produce various specifications of Hastelloy B2 seamless pipeHastelloy B2 steel plateHastelloy B2 round bar, Hastelloy B2 forgings, Hastelloy B2 flangeHastelloy B2 pipe fittings, Hastelloy B2 welded pipe, Hastelloy B2 steel strip, Hastelloy B2 wire and supporting welding materials. 

Delivery status:

  • Seamless pipe: solid solution + acid white, length can be set;
  • Plate: solid solution, pickling, trimming;
  • Welded pipe: solid solution acid white + RT% flaw detection;
  • Forging: annealing + car polish; Bars are forged and rolled, surface polished or car polished;
  • Strips are delivered after cold rolling, solid solution soft state, and deoxidized;
  • Wire rods are finely ground in solid solution pickled disk or straight strips, solid solution straight strips Delivery in light state.

Source: China Hastelloy B2 Flanges Manufcturer – Yaang Pipe Industry (

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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Nickel-based super alloy: Hastelloy B2 (UNS N10665)
Hastelloy B2 (UNS N10665/W.Nr. 2.4617/Alloy B2) is a solid solution strengthened nickel-molybdenum alloy with low addition of carbon, silicon & iron.
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