Stainless steel
AISI 347
Manufacturer or standards-body identification; product values do not apply to every form or condition.
Identity / state reference
What distinguishes this material
Niobium/tantalum stabilization distinguishes 347 from titanium-stabilized 321. A stabilizer designation is not a blanket corrosion or elevated-temperature guarantee.
- Designation in this reference
- Type 347 / UNS S34700
- Forms covered by the sources
- Carpenter bar, billet, strip, wire and rod listings.
- States to distinguish or confirm
- Specify annealing/stabilization condition and actual exposure requirement.
- Temperature and exposure
- No universal service-temperature limit or room-temperature property set is assigned. Use the cited product document and the purchase certificate.
Other search names in these sources
UNS S34700
Read the scope above: a source’s related product name is not a blanket interchangeability statement.
Property evidence for a stated condition
No condition-specific numerical table is reproduced here
The linked sources establish the identity and the stated product/state scope. Obtain the row for your actual form, section, treatment and test conditions before adopting strength, hardness or a thermal limit.
Resolve these conditions next
- What product standard, edition and complete grade are on the material certificate?
- What product form, section size and delivery/heat-treatment condition will be machined?
For machining, take the exact grade, supplied condition and measured hardness where applicable into the tool maker’s application data. A generic material-family speed is not a substitute for an operation and tool-specific recommendation.
Sources and what they establish
Reviewed 23 October 2026. A source’s publication date and the review date are different. The scope below identifies the fields checked.
Carpenter Type 347 alloy page
UNS S34700 and niobium/tantalum stabilization; source table has a suspicious mislabeled composition row, which is not reproduced.
Carpenter Type 347 alloy page ↗Source identity, a named product example and a supplied-batch certificate are different evidence. Cross-standard similarity does not approve substitution.
Corrections from the previous article
- Correct generic equivalence presentation and omit the source’s suspicious composition-row label rather than copying it as copper chemistry.
- Withdraw the legacy generic hardness (95 HRB) and tensile-strength (655 MPa (95 ksi)) pair: the old page does not establish a matching product, heat treatment, section and test source.
- Remove the unsupported cutting-speed table and machinability percentage; select tooling only after the actual material condition is known.
Other references in Stainless steel
Related references, not equivalent substitutes.