Postalloy® 2521-B

Postalloy® 2521-B is a cobalt base hardfacing alloy offering good strength and toughness at elevated temperatures up to 1500 °F (816 °C), and is used for weld overlaying of hot-working dies and valves. A low carbon content weld deposit with dispersed hard carbides provide excellent resistance to thermal shock, galling, corrosion, and cavitation erosion. These deposits are strengthened by the addition of molybdenum and are very stable in thermal cycling environments.

  • Weld deposits exhibit superior resistance to heat checking, spalling and chipping.
  • Excellent resistance to corrosive environments, and outstanding resistance to cavitation, erosion and thermal shock.
  • Resists oxidizing and reducing atmospheres up to 2100 °F (1149 °C).
  • Postalloy® 2521-B also provides excellent resistance to corrosive environments.


Product Type

  • Tig
  • Oxy-fuel
  • Cobalt Base Hardfacing Alloy


  • Forging dies, Hot trimming dies, Hot shears, Cavitation repair, chemical and petrochemical valves, Forging dies, Steam and fluid control valve bodies and Seamless pipe piercing mandrels.

Weld Deposit Properties

Hardness as Welded:
Work hardens over 40Rc
Deposits have very little tendency to relief check
Deposit Thickness:
2 layers
Fully machinable

Welding Parameters

Current Type: DC Electrode Negative

Volts Amps Gas Tig
15-25 50-80 100% Ar .045" (1.2mm)
15-25 55-90 100% Ar 1/16" (1.6mm)
15-25 75-100 100% Ar 3/32" (2.4mm)
15-30 90-120 100% Ar 1/8" (3.2mm)
15-30 120-140 100% Ar 5/32" (4mm)
15-30 140-160 100% Ar 3/16" (4.8mm)
Oxyacetylene Tip Size Flame
.045" (1.2mm) 3 3x-4x
1/16" (1.6mm) 3-4 3x-4x
3/32" (2.4mm) 3-4 3x-4x
1/8" (3.2mm) 4 3x-4x
5/32" (4mm) 4 3x-4x
3/16" (4.8mm) 5 3x-4x

Welding Procedure:

Packaging Options

Diameter Standard Packaging
All Diameters 10 lb (4.54kg) tubes