Project Description

Overview

F6NM (UNS S41500 / AISI 415) is a low-carbon soft martensitic stainless steel containing ~13% Cr, 4% Ni, and 0.5% Mo. Compared with conventional 13Cr grades (410 / 420), its higher Ni and near-zero C deliver superior sub-zero toughness, better weldability, and improved resistance to SSC and pitting. Qualified to NACE MR0175/ISO 15156; service range −60 °C to 300 °C. Primary sectors: oil & gas, hydropower, petrochemical, marine, power generation.

F6NM UNS S41500 martensitic stainless steel round bar
F6NM (UNS S41500) round bar — soft martensitic SS forging grade

Equivalent Grades

System Designation Specification(s)
ASTM / ASME / UNS F6NM · S41500 · AISI 415 · CA6-NM A182, A240, A276, A473, A479
EN / DIN 1.4313 · X3CrNiMo13-4 EN 10088-3 · EN 10222-5
JIS SCS5 · SUSF415 · SUS 415 JIS G4305
AFNOR Z4CND13.4M · Z6CND13-04 NF A35-574
BS 425C11 · 415S17 BS EN 10028

Applications

Industry Parts / Components
Oil & Gas Valve bodies, gate valves, valve seats & gates, pump shafts, compressor discs, wellhead housings, Christmas tree components, flanges, tubulars
Hydropower Turbine runners, turbine blades, turbine casings, hydraulic turbine shafts
Power Generation Reactor pressure vessels, boiler fittings, pump impellers, forged nozzles
Marine / Subsea Propeller shafts, hull reinforcements, subsea actuators, riser clamps
Chemical / Petrochem Centrifuges, heat exchangers, compressor impellers, reactor vessels

Supply Forms & Dimensions

Form Key Standard Typical Size
Round Bar ASTM A276 · A479 Ø 10–800 mm
Flat Bar ASTM A276 t ≥ 5 mm, custom width
Plate / Sheet ASTM A240 · ASME SA240 t 1–200 mm
Seamless Pipe / Tube ASTM A213 · A312 Custom OD / WT
Wire / Wire Rod ASTM A580 Ø 0.1–13 mm
Forging (ring / disc / shaft) ASTM A182 · A473 Custom

Chemical Composition

Per ASTM A182 / A240 (UNS S41500), heat analysis, wt%:

C Cr Ni Mo Mn Si P max S max
≤ 0.05 11.5–14.0 3.50–5.50 0.50–1.00 0.50–1.00 ≤ 0.60 0.030 0.030

Mechanical Properties

Per ASTM A182 / A479, SA+DT condition, minimum values:

Condition UTS (MPa) YS (MPa) El. (%) RA (%) Hardness CVN
Q+T (standard) ≥ 795 ≥ 620 ≥ 15 ≥ 40 22–28 HRC > 27 J @ −46 °C
NACE sour service ≥ 700 ≥ 550 ≥ 18 ≥ 50 ≤ 23 HRC ≥ 55 J @ 0 °C

Heat treatment: solution anneal 950–1050 °C → quench (air or oil) → double temper 550–620 °C. PREN ≈ 18–22. Density 7.85 g/cm³. Thermal conductivity ~25 W/m·K.