Alloy 31: Complete Properties & Application Guide

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Overview

Alloy 31 (UNS N08031 / W.Nr. 1.4562) is a high-chromium nickel-iron-molybdenum alloy with nitrogen addition that provides excellent resistance to pitting and crevice corrosion in chloride environments. The nitrogen addition significantly improves the alloy's PREN (Pitting Resistance Equivalent Number).

Chemical Composition

The chemical composition of Alloy 31 is carefully controlled to achieve its unique combination of properties and performance characteristics.

Element	Min %	Max %
Iron (Fe)	Balance	Balance
Nickel (Ni)	30.0	32.0
Chromium (Cr)	26.0	28.0
Molybdenum (Mo)	6.0	7.0
Nitrogen (N)	0.15	0.25
Copper (Cu)	1.0	1.40
Carbon (C)	—	0.02
Manganese (Mn)	—	2.0

Mechanical Properties at Room Temperature

The mechanical properties of Alloy 31 vary depending on product form and heat treatment condition. The data below represents typical values for solution-annealed material.

Property	Value
Tensile Strength	700 MPa
Yield Strength (0.2% offset)	320 MPa
Elongation in 2 inches	50%
Density	8.10 g/cm3
Melting Point	1350 °C
Max Service Temperature	700 °C

Corrosion Resistance

Excellent resistance to pitting and crevice corrosion in chloride-containing environments. Good resistance to sulfuric acid at medium and high concentrations. Outstanding resistance to caustic environments. Superior to 904L in many aggressive media.

Applications

The unique combination of properties makes Alloy 31 suitable for a wide range of demanding applications:

• Flue Gas Desulfurization: Scrubber components and absorber internals in FGD systems.
• Chemical Processing: Heat exchangers and piping in sulfuric acid service.
• Oil & Gas: Clad steel for offshore and subsea applications.
• Pulp and Paper: Digester vessels and bleaching equipment.
• Seawater: Cooling water systems and heat exchangers.

Available Product Forms

Hangbo Alloy Group manufactures and supplies Alloy 31 in the following product forms, conforming to ASTM, AMS, and ASME specifications:

• Round Bars: Diameters from 6 mm to 300 mm, hot-finished or cold-drawn, solution annealed.
• Seamless Tubes & Pipes: Sizes from 6 mm OD to 219 mm OD, various wall thicknesses.
• Plates & Sheets: Thicknesses from 0.5 mm to 50 mm, hot-rolled or cold-rolled.
• Forgings: Custom flanges, rings, discs, and complex shapes per customer drawing.
• Welding Wire: Diameters 0.8 mm to 5.0 mm, precision-wound coils and spools.

Related Standards

Standard	Description
ASTM B625	Plate, Sheet, and Strip
ASTM B622	Seamless Pipe
ASTM B619	Welded Pipe
ASTM B690	Seamless Tube
ASTM B366	Fittings
VdTUV 521	German Approval

Contact Us for Alloy 31

Hangbo Alloy Group maintains extensive inventory of Alloy 31 in all standard product forms. We can provide mill test certificates, third-party inspection reports (SGS, TUV), and custom processing services.

For quotations, material certifications, or technical consultation, contact our sales team or call +86-136-1165-6360. We typically respond within 10 minutes.