Hastelloy G3(Ni-Cr-Mo-Co)

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1. Introduce

– Ni-Cr alloy with Mo, Co and Cu additions

– Cold hardenable Ni alloy designed for corrosion resistance in strongly acidic (H₂S) environments

– High corrosion resistance in strongly acidic environments up to about 204°C

– More Cr and less Mo than Hastelloy C for improved corrosion resistance in oxidizing environments

– UNS N06985

* UNS

Abbreviation of Unified Numbering Systems for Metals and Alloys
Unified unique numbering system for metals and alloys
A representative number that is compatible with metals and alloys defined in many material-related codes such as ASTM, AISI, ASME, AWS, etc.

* N : Nickel and nickel alloys

* UNS N06985 : 06XXX : Chromium(Hastelloy, Inconel, some with additional element)

* Hastelloy

– A corrosion-resistant alloy with Ni as the main component

– Excellent machinability, weldability, and can be machined into various shapes

– Main types and characteristics

Hastelloy B
* Main composition
– Ni-Mo
* Characteristics
– Hydrochloric acid-resistant alloy : Excellent hydrochloric acid resistance by containing a large amount of Mo
– Corrosion resistance in non-oxidizing atmosphere, excellent resistance to hydrogen chloride gas and reducing solution
Hastelloy C
* Main composition
– Ni-Cr-Mo
* Characteristics
– Oxidation resistance alloy : Excellent oxidation resistance by containing a large amount of Cr
– Excellent corrosion resistance in oxidizing atmospheres such as nitric acid and chlorine due to the addition of Cr
Hastelloy G
* Main composition
– Ni-Cr-Fe-Mo
* Characteristics
– Reinforced with Mo, Cu to improve corrosion resistance to sulfuric and phosphoric acids
– Good corrosion resistance in welds, good chloride intergranular corrosion resistance
Hastelloy X
* Main composition
– Ni-Cr-Fe-Mo
* Characteristics
– Alloy designed for good oxidation resistance at 1200 degrees, Good corrosion resistance in oxidizing, sulfuric and phosphoric acid atmospheres

2. Property

– Low C content
→ Excellent weldability and intergranular corrosion resistance under welding conditions
→ Sensitization of weld heat affected zone and excellent intergranular corrosion resistance

(High C content → Increased precipitation carbides in grains → Poor corrosion resistance)

Element	Impact
Ni	Provides corrosion resistance
Cr	Provides oxidizing and non-oxidizing acid resistance
Cu	Provides reducing chemical resistance, weldability, and ductility
Si	Forms stable oxide film, increases chromium oxide film stability
Mn	Provides machinability, weldability → Prevents formation of grain boundary deposits in the weld heat zone → Can be used in the as-welded condition for chemical process applications
Mo	Provides localized corrosion resistance
Co	Provides strength, creep properties
W	Provides corrosion resistance

[Hastelloy G3 Chemical Composition (%)]

Ni	Cr	Fe	C	Cu
35.91 ~ 53.50	21.00 ~ 23.50	18.00 ~ 21.00	Max. 0.02	1.50 ~ 2.50

Si	Mn	Mo	S	Co
Max. 1.00	Max. 1.00	6.00 ~ 8.00	Max. 0.03	Max. 5.00

W	P	Nb + Ta
Max. 1.50	Max. 0.04	Max. 0.50

[Hastelloy G3 Mechanical Properties]

Tensile Strength (Mpa)	Yield Strength (Mpa)	Elongation (%)
Min. 690	Min. 320	Min. 50

[Hastelloy G3 Physical Properties]

Density (g/cm³)	Melting Range (℃)	Specific Heat (0~100℃), *J/kg℃**
8.14	1260 ~ 1343	453 (25℃)

3. Standard & Specification

– Specification : UNS N06985

Product Form	ASTM	ASME
Coil, Strip, Foil	B581, B582	SB582
Bar, Wire, Forgings	B581	–
Plate, Sheet, Strip	B582	–
Pipes, Tubes	B619, B622, B626	B619, B622, B626

4. Available Form

– Coil, Strip, Foil

– Bar, Wire, Forgings

– Plate, Sheet, Strip

– Pipe, Tube

5. Application & Product

– Gas & Oil, Nuclear Power

Application	Product
Gas & Oil	Oil well pipes, wet phosphoric acid production evaporators
Nuclear Power	Nuclear fuel tanks, nuclear fuel reprocessing equipment, pickling equipment