ASTM A959:2011 420F: Martensitic stainless steel type 420F (UNS S42020) with the composition limits of ASTM A959-11. Carbon 0.30-0.40% and chromium 12.0-14.0%.
Matched by chemical composition and mechanical properties, not a formal equivalence claim. Always verify against the applicable standard before substitution.
Chemical Composition (%)
C
Cr
Mn
Mo
P
S
Si
0.30-0.40
12.0-14.0
<=1.25
<=0.50
<=0.06
>=0.15
<=1.00
More data from ASTM A959:2011
From the standard
Other composition limitsfrom Table 1 and its footnotes
UNS number
S42020
Metallurgical class
Martensitic grade: can be hardened by heat treating and quenching and then tempered; delivered annealed or hardened and tempered
Type
420F (designation originally assigned by the American Iron and Steel Institute)
Values
Maximum unless a range or minimum is shown; where two limits are shown for the same element in one grade the more stringent applies
These are the recommended composition limits of the A959 guide, intended for adoption by standards for stainless steel products; they are not a product specification.
Source: ASTM A959:2011, Table 1 and its footnotes
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