Material number S41000: 410
S41000 is the Unified Numbering System designation for 410, martensitic chromium stainless steel, hardenable specified in ASTM A276.
What S41000 means
UNS numbers (ASTM E527 / SAE J1086) use a letter for the alloy family and five digits: G = AISI/SAE carbon and alloy steels (G41400 = 4140), S = stainless and heat-resisting steels (S30400 = 304), K = miscellaneous steels (K02600 = A36), T = tool steels, N = nickel alloys. The UNS number identifies a composition, not a product form or property level, so S41000 appears in several ASTM specifications (plate, bar, pipe) with different mechanical requirements.
410 at a glance
Type 410 is the basic martensitic stainless steel: 12 % chromium with about 0.1 % carbon, which is just enough to transform to martensite on quenching and reach 38–45 HRC. It is the cheapest stainless that can be heat-treated to high strength, so it is the material of pump shafts, valve trim and seats, steam-turbine blades, fasteners, cutlery blanks, mining screens and press-plate — anywhere hardness or 800–1200 MPa strength matters more than corrosion resistance. UNS S41000; EN 1.4006 (X12Cr13).
Its corrosion resistance is the lowest of the common stainless grades (PREN ≈ 12), adequate for fresh water, steam, mild chemicals, petroleum and food oils but not for chlorides or acids; and it must be used in the hardened-and-tempered condition, because annealed 410 corrodes faster and tempering at 400–550 °C embrittles it. Properly heat-treated 410 is magnetic and tough enough for shafts down to about −20 °C.
The family runs 410S (low carbon, non-hardening, for welded plate) → 410 → 416 (free-machining) → 420 (higher carbon, 50+ HRC) → 440 (very high carbon, 58 HRC). JIS SUS410, GB 12Cr13 and GOST 12Kh13 are the same grade.
Full data sheet for 410 → · Equivalent grades →