Material number 1.5415: 16Mo3
1.5415 is the European material number (Werkstoffnummer, EN 10027-2) for 16Mo3, molybdenum-alloyed steel for pressure purposes at elevated temperature specified in EN 10028-2.
What 1.5415 means
EN 10027-2 material numbers have the form 1.XXYY: the leading 1 is steel; the next two digits give the steel group (54 → Mo / Nb / Ti / V / W steels); the last two digits are a sequential number within that group. The number is unique to one composition and survives name changes, which is why 1.5415 has stayed constant while the symbolic name moved from 15Mo3 to 16Mo3.
16Mo3 at a glance
16Mo3 is the first alloy step above carbon steel in the European pressure-vessel range: 0.3 % molybdenum in a 0.16 % carbon matrix, Werkstoff number 1.5415, specified in EN 10028-2 (plate), EN 10216-2 (seamless tube), EN 10222-2 (forgings) and EN 10273 (bar). The old DIN 17155 name 15Mo3 is still heard daily.
Molybdenum does two things: it raises the yield strength that can be guaranteed at 400–500 °C (148 MPa at 500 °C, versus P265GH's table ending at 400 °C) and it slows creep, so 16Mo3 is the economical choice for boiler tubes, superheater headers, steam drums, hot-gas ducting and refinery vessels operating between roughly 400 and 530 °C. Room-temperature values are 275 MPa yield, 440–590 MPa tensile, 24 % elongation, 27 J at −20 °C.
The ASME counterparts are C-½Mo grades — A204 (plate), A335 P1 (pipe), A182 F1 (forgings) — which carry 0.45–0.60 % Mo, so the match is 'near'; note that ASME has restricted C-½Mo in hydrogen service (API 941), a caution that applies equally to 16Mo3.
Full data sheet for 16Mo3 → · Equivalent grades →