Alloy 31, 1.4562, UNS N08031, VDM® Alloy 31 - nickel alloy

Alloy 31, 1.4562, UNS N08031, VDM® Alloy 31 - nickel alloy according to ASTM B625, NACE MR0175 / ISO 15156 and API 6ACRA

Alloy 31, 1.4563, VDM® Alloy 31– description

Alloy 31 is an iron-nickel-chromium-molybdenum alloy with nitrogen alloying addition. It has a face-centred cubic lattice. The 0.2% nitrogen content stabilizes the austenite and reduces the precipitation rate of intermetallic sigma phases. Technically qualified as a stainless steel, in reality, it covers the gap between high alloyed stainless steel and nickel alloys, performing some tasks as well as the latter while lowering the costs. Alloy 31 is included in the list of the German Federal Institute for Materials Research and Testing for transport and storage containers for hazardous goods. It is approved by VdTÜV for pressure vessels from -196°C up to 550°C. VDM® Alloy 31 is included in NACE MR0175 / ISO 15156:2003, (as well as API 6ACRA), and certified up to level CI for acid gas applications.

Applications

Alloy 31 is used in chemical and petrochemical industries for components for flue gas desulfurization plants, phosphoric acid production plants, pipes and heat exchangers for sulfuric acids contaminated with chlorides, in paper and cellulose industry, in ore digestion plants, in oil and gas extraction for pipes, slicklines, wirelines and flowlines transporting oil and gas, and finally in marine engineering.

Physical and Tensile Properties

Room temperature physical properties:

• Density: 8.05 g/cm³
• Melting Temperature: 1330-1370 °C
• Magnetic Permeability: 1.001

High-temperature Coefficient of thermal expansion, from 20°C to:

• 100°C: 14.3 μm/m⋅K
• 200°C: 14.7 μm/m⋅K
• 300°C: 15.1 μm/m⋅K
• 400°C: 15.5 μm/m⋅K
• 500°C: 15.7 μm/m⋅K
• 600°C: 15.9 μm/m⋅K

Thermal Conductivity:

• 20°C: 11.7 W/m · K
• 100°C: 13.2 W/m · K
• 200°C: 15 W/m · K
• 300°C: 16.8 W/m · K
• 400°C: 18.5 W/m · K
• 500°C: 20.2 W/m · K
• 600°C: 21.9 W/m · K

Electrical Resistivity:

• 20°C: 1.04 μΩ·m
• 100°C: 1.07 μΩ·m
• 200°C: 1.1 μΩ·m
• 300°C: 1.13 μΩ·m
• 400°C: 1.16 μΩ·m
• 500°C: 1.18 μΩ·m
• 600°C: 1.2 μΩ·m

Young's Modulus:

• 20°C: 198 GPa
• 100°C: 189 GPa
• 200°C: 183 GPa
• 300°C: 176 GPa
• 400°C: 170 GPa
• 500°C: 163 GPa
• 600°C: 158 GPa

High-Temperature Mechanical Properties of alloy 31 plates, annealed and quenched, according to VdTÜV material data sheet 509:

• 20°C:
  • Yield strength: >280 MPa
  • Tensile strength: >650 MPa
  • Elongation: >40%
• 100°C:
  • Yield strength: >210 MPa
  • Tensile strength: >630 MPa
  • Elongation: >40%
• 200°C:
  • Yield strength: >180 MPa
  • Tensile strength: >580 MPa
  • Elongation: >40%
• 300°C:
  • Yield strength: >165 MPa
  • Tensile strength: >530 MPa
  • Elongation: >40%
• 400°C:
  • Yield strength: >150 MPa
  • Tensile strength: >500 MPa
  • Elongation: >40%
• 500°C:
  • Yield strength: 135 MPa
  • Tensile strength: 470 MPa
  • Elongation: >40%
• 550°C:
  • Yield strength: 125 MPa
  • Tensile strength: 450 MPa
  • Elongation: >40%

Impact Strength

• 20°C: > 185 J/cm2
• -196°C: > 140 J/cm2

Corrosion Resistance

Alloy 31 has good corrosion resistance, when used in solution annealed, clean and metallic bright condition.

Halide-containing media - good resistance.

Sulfuric acid - very good resistance up to 80°C.

Phosphoric acid - good resistance. Alloy 31 has been successfully used in pulp and paper processing plants.

Intercrystalline corrosion - fair to good resistance. Testing in accordance with ASTM G28 (method A) and SEP 1877 II shows that Alloy 31 becomes sensitized only after prolonged exposure - after 10h in 650°C and after 100h in 590°C.

Pitting - fair resistance. The critical pitting temperature in 10% FeCl3 x 6 H₂O (ASTM G48) is 85°C.

Hydrochloric acid - fair resistance in low concentrations (up to 5%).

Weldability

Alloy 31 has good weldability. Please follow the usual procedures for welding high alloyed stainless steel. Preheating is not required.

Pre- and post-weld heat treatment are normally not necessary. However, if the component has already been used at 600-650°C before welding, then stabilizing annealing is recommended after welding, before it is used in this critical temperature range.

Selection of welding consumables:

• Filler metal - ERNiCrMo-13 (VDM® FM 59) or N08031 (VDM® FM 31)

Heat Treatment, Working and Machining

Recommended heat treatment and hot work parameters:

• Hot working: 1200-1050 °C; rapid air cool / water quench
• Solution-treatment: 1150-1180 °C; rapid air cool / water quench

For best corrosion resistance, the component should be rapidly cooled (> 150°C/min) from solutioning temperature down to 500°C.

Cold forming should be carried out on solution-treated workpieces. Due to the hardening of the alloy, intermediate annealing is often necessary. For cold forming of >15% a final solution annealing is required.

We deliver this steel alloy as:

• Rod, bar, wire, forging according to ASME SB-581 / ASTM B581, ASME SB-649 / ASTM B649
• Sheets and plates according to ASME SB-625 / ASTM B625
• Rod, bar, wire, forging, sheet, plate according to VdTÜV 509, SEW 400

Replacements, equivalents and other designations:

Alloy 31, 1.4562, X1NiCrMoCu 32-28-7, VDM® Alloy 31, Nicrofer® 3127 hMo, UNS N08031, NAS 325N, ASTM B 366 (CR3127) / ASME SB-366 (CR3127), ASTM B 366 (WP3127) / ASME SB-366 (WP3127), ASTM B 366 (WPR3127) / ASME SB-366 (WPR3127), ASTM B 462 (N08031) / ASME SB-462 (N08031), ASTM B 472 (N08031) / ASME SB-472 (N08031), ASTM B 564 (N08031) / ASME SB-564 (N08031), ASTM B 581 (N08031) / ASME SB-581 (N08031), ASTM B 619 (N08031) / ASME SB-619 (N08031), ASTM B 622 (N08031) / ASME SB-622 (N08031), ASTM B 625 (N08031) / ASME SB-625 (N08031), ASTM B 626 (N08031) / ASME SB-626 (N08031), ASTM B 649 (N08031) / ASME SB-649 (N08031)