Hastelloy vs Monel

Difference between Hastelloy and Monel alloy

Stronger than steel, monel is a malleable, highly corrosion resistant material. In addition to superior resistance to alkali media, this alloy group has good resistance to highly corrosive acids for instance - hydrofluoric and sulfuric acid. And because monel contains a higher content of copper, they serve marine engineering applications really well. The content of copper also imparts some resistance to biofouling, which is why monel components work well in brine solutions.  On the other hand, Hastelloys exhibit Good resistance to acidic solutions. These corrosive acids include solutions of sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid as well as chromic acid. In particular, the resistance of these alloys to sulfuric acid is an important contribution to processing based industries, as very few alloys exhibit good resistance to this acid. Another vital characteristic of the alloy is its excellent resistance to stress related corrosion cracking. And because the content of nickel is high, the material could be used at elevated temperatures. The addition of chromium to Hastelloy improves its resistance to oxidation corrosion, while also making these alloys resilient to uniform attack as well as localized corrosion resistance.

Difference between Hastelloy and monel material price

Unlike Hastelloy which contains several other elements in its chemical composition, most monel alloys contain nickel between  60% to 70% in their chemistry. Since the cost of nickel is volatile, and the metal is a commodity, the value of nickel, as a metal is considered to be high. In comparison to monel, Hastelloy has lesser nickel in its chemistry, which makes monel the more expensive metal in comparison to the former.

Nickel content in Hastelloy and monel

Although both Hastelloy and monel contain nickel in their alloys, the addition of this element in their chemistry varies. While the monel alloys contain about 30% to 40% copper added in their alloy, the content of nickel ranges between 60% to 70%, depending on the monel grade manufactured. Whereas Hastelloy contains significant additions of elements such as ferrous or iron, chromium, molybdenum, cobalt, and tungsten, the remaining percentage of nickel is added to the alloys that it is intended to be manufactured. Therefore, the content of some hastelloys is lower than monel.

How to Identify Hastelloy and monel?

While metals tend to be similar to each other in terms of appearance, one of the most effective methods to identify both alloys is to obtain a mill test report or a material test report. In most cases, manufacturers are able to procure an MTR or a mill test report for the buying party, as a means of assuring the quality of the product. Generally, a material test report chronicles a detailed test report of the elemental composition of the material as well as its mechanical or physical properties.

Hastelloy and monel melting point

It is typical to note that several alloys do not have a single melting point, but, unlike pure metals, these alloys exhibit a melting range or a melting point. During this temperature range, the material or alloy is a mixture of both solid and liquid phases. This mixture of phases is referred to as a slush. The melting point of most monel alloys is around a temperature of 2460 °F. While the melting point of Hastelloy grades is slightly higher ranging at about 2550 °F.

Hastelloy and monel yield strength

Yield Strength of a material is calculated as the stress the metal, or in this case, alloys can withstand without permanent deformation or a limit at which the said material will cease to return to its original dimensions, which is about 0.2% of its length. The yield strength at 0.2% Offset of various Hastelloy grades ranges between 310 Mpa to about 355 Mpa. Whereas, for monel alloys, the yield strength at 0.2% Offset could range anywhere between 240 Mpa to about 790 Mpa.

Monel and Hastelloy ultimate tensile strength

Unlike the yield strength that is calculated at 0.2% offset, the tensile strength of a material is the maximum stress which the alloy can endure while it is being stretched or pulled prior to either failure or break. The tensile strength of Monel alloys falls between a range of 550 Mpa to about 1100 Mpa. And in comparison to monel, the tensile strength of several Hastelloy grades falls in between the range of 690 Mpa to about 783 Mpa.

Monel equivalent grade

ALLOY WERKSTOFF NR. (WNR) UNS AFNOR GOST BS JIS EN
Monel 400 2.4360 N04400 NU-30M МНЖМц 28-2,5-1,5 NA 13 NW 4400 NiCu30Fe
Monel 404 2.4867 N04404          
Monel 405   N04404          
Monel K500 2.4375 N05500          

Monel chemical compatibility chart

ALLOY ASTM/ AISI UNS %Al %Cu %Mn %Ni %Ti %Fe %Si
Monel 400 B 127, B 164 N04400 28-34 2.0 max 63 min 2.5 max 0.5 max
Monel 401 N04401 28-34 2.0 max 63 min 2.5 max
Monel 404 N04404 0.05 max Rem 0.1 max 52-57 0.5 max 0.1 max
Monel K-500 B 865 N05500 2.3-3.15 27-33 1.5 max 63 min 0.35-0.85 2.0 max 0.5 max
Monel 405 B 164 N04405 28-34 2.0 max 63 min 2.5 max 0.5 max

Monel yield and tensile strength

 ALLOY Tensile Strength Yield Strength (0.2%Offset) Density Melting Point Elongation
Monel 400 Psi – 80000 , MPa – 550 Psi – 35000 , MPa – 240 8.8 g/cm3 1350 °C (2460 °F) 40 %
Monel 404 70 KSI min (483 MPA min) 25 KSI min (172 MPA min) 8.91 gm/cm3 1300 - 1350℃ 35 %
Monel 405 550 Mpa 240 Mpa 8.80 g/cm3 1300 - 1350°C 40 %
Monel K500 Psi – 160000 , MPa – 1100 Psi – 115000 , MPa – 790 8.44 g/cm3 1350 °C (2460 °F) 20 %

Hastelloy material grades

  • HASTELLOY B2 ®
  • HASTELLOY C ®
  • HASTELLOY C276 ®
  • HASTELLOY N ®
  • HASTELLOY S ®
  • HASTELLOY W ®
  • HASTELLOY X ®

Hastelloy equivalent

STANDARD WERKSTOFF NR. UNS GOST AFNOR JIS OR EN
Hastelloy C22 2.4602 N06022 - - NW 6022 - NiCr21Mo14W
Hastelloy C276 2.4819 N10276 ХН65МВУ - NW 0276 ЭП760 NiMo16Cr15W
Hastelloy B2 2.4617 N10665          
Hastelloy B3 2.4600 N10675          
Hastelloy C4 2.4610 N06455          
Hastelloy C-22HS - N07022          
Hastelloy C2000 2.4675 N06200          
Hastelloy Hybrid BC1 2.4708 N10362          
Hastelloy X 2.4665 N06002          

Hastelloy mechanical properties

  Density Melting Point Tensile Strength Yield Strength (0.2%Offset) Elongation
C22 8.69 g/cm3 1399 °C (2550 °F) Psi – 1,00,000 , MPa – 690 Psi – 45000 , MPa – 310 45 %
C276 8.89 g/cm33 1370 °C (2500 °F) Psi – 1,15,000 , MPa – 790 Psi – 52,000 , MPa – 355 40%
B2 9.2 g/cm3 1370 °C (2550 °F) Psi – 1,15,000 , MPa –760 Psi – 52,000 , MPa – 350 40%
B3 9.2 g/cm3 1370 °C (2550 °F) Psi – 1,15,000 , MPa –760 Psi – 52,000 , MPa – 350 40%
C4 8.64 g/cm3 1350-1400 °C 783 365 55%
Hybrid BC1 8.83 g/cm³ 1343 - 1443°C 725 310 40%
X 8.22 g/cm³ 1355°C 655 MPa 240 MPa 35%

Hastelloy chemical compatibility

Material / Purity (%):

C-276

C-22
Ni 57.0 56.0
Co 2.50 2.50
Cr 15.5 22.0
Mo 16.0 13.0
W 4.00 3.00
Fe 5.50 3.00
Si 0.080 0.080
Mn 1.000 0.500
P 0.025 0.010
S 0.010 0.020
V 0.350 0.350

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