347

UNS #S34700

347 is a columbium/tantalum stabilized austenitic stainless steel that resists carbide precipitation during welding and intermittent heating to 800/1650°F (427/899°C). It has good high temperature scale resistance and, like 321 stainless, has superior intergranular-corrosion resistance compared to typical 18-8 type alloys. Since columbium and tantalum have stronger affinity for carbon than chromium, carbides of those elements tend to precipitate randomly within the grains instead of forming continuous patterns at the grain boundaries.

Type Analysis

  • Carbon (Maximum) 0.08
  • Phosphorus (Maximum) 0.045
  • Silicon (Maximum) 1
  • Nickel (Nominal) 9.00-13.00
  • Manganese (Maximum) 2
  • Sulfur (Maximum) 0.03
  • Chromium (Nominal) 17.00-19.00
  • Iron (Nominal) Balance
  • Copper (Nominal) 10 X C Minimum

Applications

aircraft collector rings and exhaust manifolds, expansion joints and high temperature chemical process equipment

Applicable Specifications

  • ASME SA479
  • ASTM A479
  • QQ-S-763

Billet

Rod

Rounds

Strip

Wire

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