Mo-alloyed pressure vessel steel for service to 530 C. Standard for superheater headers and boiler drums at elevated temperature.
Standards
| Standard Body |
Designation |
Country |
| EN 10028-2 |
16Mo3 / 1.5415 |
EU |
| ASTM |
A335 P1 (nearest) |
USA |
| ASME |
SA-335 P1 |
USA |
| DIN (obs.) |
15Mo3 / 1.5415 |
Germany |
| JIS |
STBA12 |
Japan |
| GOST |
16M |
Russia |
| JUS |
C.0454H |
Yugoslavia |
Composition (wt.%)
| Element |
Symbol |
Min % |
Max % |
Typical % |
| Carbon |
C |
0.120 |
0.200 |
0.160 |
| Manganese |
Mn |
0.400 |
0.900 |
0.650 |
| Molybdenum |
Mo |
0.250 |
0.350 |
0.300 |
Physical
Melting Range
1480 – 1518
°C
Thermal Conductivity
47
W/mK
Thermal Expansion
12.5
×10⁻⁶/K
Machinability
| Rating |
58.0% (B1112=100%) |
| Turning HSS |
34.0 m/min |
| Turning Carbide |
155.0 m/min |
| Surface Finish |
Ra 1.6-3.2 um |
| Coolant |
Soluble oil 5-8% |
Mechanical
| Condition |
Rm (MPa) | Re (MPa) | A (%) |
HB | HRC | KV (J) | E (GPa) |
| Normalized t<=16mm (+N) |
450 – 600 |
≥275 |
≥22 |
— |
— |
— |
210 |
Heat Treatment
| Process |
Temperature |
Medium |
Duration |
Hardness After |
| Normalizing |
880 – 940°C |
Still Air |
- |
Delivery |
| PWHT |
640 – 660°C |
Furnace |
1h/25mm |
No change |
Applications
Power Generation: Superheater headers and main steam piping at 450-530 C.
Petrochemical: High-temperature process piping and reactor nozzles at 400-530 C.
Notes
16Mo3 vs P265GH: P265GH loses strength above 300 C. 16Mo3 Mo addition retains strength to 530 C.