347 Stainless Steel Bar

UNS S34700 (Grade 347)

347 stainless steel bar, also known as UNS S34700 and Grade 347, is an austenitic stainless steel made of .08% maximum carbon, 17% to 19% chromium, 2% maximum manganese, 9% to 13% nickel, 1% maximum silicon, traces of phosphorus and sulfur, 1% minimum to 10% maximum columbium and tantalum with the balance of iron. Grade 347 is advantageous for high temperature service because of its good mechanical properties; it also has excellent resistance to intergranular corrosion following exposure to temperatures in the chromium carbide precipitation range from 800° to 1500° F. It is similar to Grade 321 with respect to intergranular corrosion which is achieved through the use of columbium as a stabilizing element to maximize this feature. Grade 347 can not be hardened through heat treating, but elevated properties may be obtained through cold reduction.

Industries that use 347 include:

  • Aerospace
  • Valve

Products partially or completely constructed of 347 include:

  • Aircraft collector rings
  • Chemical production equipment
  • Engine parts
  • Exhaust manifolds
  • High temperature gaskets and expansion joints
  • Rocket engine parts
Stocking Diameters ½” to 24”
Material Lengths Up to 12’
Bar Specifications
Uns Type Ams Astm Federal Characteristics
S34700 347 5646
QQ-S-763 347 is overall superior to 321, but with similar characteristics. 347 is stabilized by cobalt and tantalum, easily welded, resists intergranular corrosion.
Chemistry Analysis
.08 2. .045 .03 1. 17. – 19. 9. – 13. .5 .5 Cb + Ta = 10xC Max. NM

The information above is not warranted, guaranteed, or for design purposes.

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