Alloy 31 (UNS N08031)

Alloy 31 (UNS N08031) is an iron-nickel-chromium-molybdenum alloy with nitrogen and copper additions which has hybridized properties of austenitic super stainless steels and regular nickel alloys. Alloy 31 has exceptional corrosion resistance to alkaline & halide-containing media, sulfuric acid, phosphoric acid, chlorine dioxide media, nitric acid as well as reducing & oxidizing medias. It is widely used in offshore & marine industries, chemical & petrochemical processing, pharmaceutical piping, oil and gas extraction, and ore digestion plants. Especially, Alloy 31 can be used for the fabrication of pressure vessels which may endure a wide temperature-range from cryogenic level to elevated temperatures(-196°C to 550 °C).

Equivalent Grades

Trademarks	GB	JIS	KS	ASTM	UNS	DIN	W.Nr	GOST	BS	NF
Nicrofer 3127hMo	NS1404	–	–	Alloy 31	N08031	X1NiCrMoCu 32-28-7	1.4562	–	X1NiCrMoCu 32-28-7	–

Product Forms

Wire, Bar, Strip, Sheet, Plate, Tube, Pipe, Pipe Fittings, Forgings

Chemical Composition, %

C	P	S	Mn	Si	Cr	Ni	Cu	Mo	N	Fe
≤0.015	≤0.020	≤0.030	≤2.00	≤0.10	26.0~28.0	30.0~32.0	1.0~1.4	6.0~7.0	0.15~0.25	Bal

Typical Physical & Mechanical Properties (RT, Solution Annealed)

Density, g/cm3	Melting Point, ℃	Tensile Strength, MPa	Yield Strength, MPa	Elongation,%
8.05	1330-1370	≥650	≥280	≥40

Specifications

Rod, Bar, Wire, Forgings	ASTM B564, ASTM B581, ASTM B649, ASME SB581, ASME SB649
Plate, Sheet, Strip	ASTM B625, ASME SB625, API 5LD
Pipe, Tube	ASTM B163, ASTM B423, ASTM B704, ASTM B705, ASTM B751, ASTM B775, ASTM B829, ASME SB163, ASME SB423, ASME SB704, ASME SB705, ASME SB751, ASME SB775, ASME SB829, ISO 6207, DIN 77751
Others	DIN 17744, ASTM B366, ASME SB366

Features

Outstanding corrosion resistance in alkaline and acidic halide-containing media
Excellent resistance to sulfuric acid, even in highly concentrated form
Excellent resistance to corrosion and erosion in phosphoric acid media
Outstanding resistance to surface corrosion and local corrosion in chlorine dioxide bleaching plants in paper production
Excellent resistance in reducing and oxidizing media as well as in boiling azeotropic nitric acid
Good workability and weldability

Applications

Components for flue gas desulfurization (FGD) plants
Plants for the production of phosphoric acid via the wet digestion process
Pipes and heat exchangers for sulfuric acids contaminated with chlorides
Pipes containing ocean water and brackish water, condensers and chillers
Pickling plants for sulfuric acid as well as nitric-hydrofluoric acid
Treatment of sulfuric acids from waste
Evaporation and crystallization of salts
Components for the cellulose and paper industry
Digestion of ores, e.g. in HIPAL (high-pressure acid leach) plants for the digestion of laterite ores
Mineral oil production and refineries
Organic acids and ester synthesis
Fine chemicals
Strain-hardened transport and feed pipes as well as slicklines, wirelines and flowlines in the transport of oil and gas