Strong Match — 96.5% match
based on chemical composition and mechanical property overlap.
ASTM A959 309HCb (ASTM A959:2011) and ASTM A240/A240M S30909 (ASTM A240/A240M:2025) are both steel grades.
Both fall under the Stainless Steel category.
ASTM A959 309HCb is typically used for wrought stainless steel products; recommended composition limits for adoption by product standards (clause 1.1), while ASTM A240/A240M S30909 is commonly used for pressure vessels and general applications (plate, sheet and strip).
ASTM A959 309HCb is defined under ASTM International, originating from United States, while ASTM A240/A240M S30909 is defined under ASTM International, originating from United States.
As per chemical composition, ASTM A959 309HCb vs ASTM A240/A240M S30909 is a 96.5% match.
Mechanical property data is not available for both grades, so this factor could not be scored.
Combined, this makes them a strong match overall at 96.5%.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Mechanical Properties
Property
ASTM A959 309HCb
ASTM A240/A240M S30909
Tensile Strength
Not specified
>=515 MPa
Yield Strength
Not specified
>=205 MPa
Elongation
Not specified
>=40%
Hardness
Not specified
<=217 HB
Condition
Not specified
Plate, sheet and strip; yield by 0.2 percent offset
Typical Applications
ASTM A959 309HCb
Wrought stainless steel products; recommended composition limits for adoption by product standards (clause 1.1)
ASTM A240/A240M S30909
Pressure vessels and general applications (plate, sheet and strip)
Can ASTM A959 309HCb Be Substituted With ASTM A240/A240M S30909?
ASTM A959 309HCb and ASTM A240/A240M S30909 overlap closely enough on chemistry and mechanical properties that ASTM A240/A240M S30909 is often considered as a substitute for ASTM A959 309HCb in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.
What is the difference between ASTM A959 309HCb and ASTM A240/A240M S30909?
Both grades share a similar composition profile; see the specification table above for the exact chemistry and mechanical property values.
Can ASTM A959 309HCb be substituted with ASTM A240/A240M S30909?
ASTM A959 309HCb and ASTM A240/A240M S30909 overlap closely enough on chemistry and mechanical properties that ASTM A240/A240M S30909 is often considered as a substitute for ASTM A959 309HCb in many applications. Always confirm the specific property range your application needs before substituting, and check with your supplier's mill certificate.