Stainless Steel 1.4852-MA (HP-Nb micro-alloyed)
Heat-treated state
EN 1.4852 · UNS J95709 · ASTM A297 Grade HP-Nb
Pick when maximum creep-rupture life and carburization/coking resistance are required for long-campaign ethylene coils.
Values for the MA condition
Other 1.4852 tempers and conditions
1.4852 is listed in 3 conditions; see the grade overview at 1.4852.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AC-CENTDefault As-cast, centrifugally cast tube | Standard supply condition for pyrolysis/reformer radiant tubes — fine columnar structure, best creep-rupture life. | 270 | 500 | 11 | 190 HB | — |
MAThis page HP-Nb micro-alloyed | Pick when maximum creep-rupture life and carburization/coking resistance are required for long-campaign ethylene coils. | 285 | 520 | 10 | 195 HB | 1.7 % IACS |
Thermally aged / service-exposed | Reference condition for repair, re-weld and remaining-life assessment of used furnace tubes — carbide coarsening raises hardness and destroys room-temperature ductility. | 300 | 470 | 3 | 220 HB | 1.8 % IACS |
What is 1.4852-MA?
1.4852-MA is 1.4852 heat treated to MA — pick when maximum creep-rupture life and carburization/coking resistance are required for long-campaign ethylene coils. 1.4852-MA has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 74% of stainless steel grades. Elongation at break is 10% and the elastic modulus is 180 GPa (26.1 Msi). 1.4852-MA has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,330°C (2,426 °F). AC-CENT is the default condition FabDigit quotes; MA is available on request or by drawing note.
Advantages
- High service temperature — 1,120°C (2,048 °F), better than 99% of stainless steel grades
Limitations
- Limited formability — 5/100, worse than 99% of stainless steel grades
- Hard to polish — 40/100, worse than 99% of stainless steel grades
- Limited ductility — 10%, worse than 98% of stainless steel grades
- Difficult to machine — 21/100, worse than 97% of stainless steel grades
- High embodied carbon — 7 kg CO₂/kg, worse than 96% of stainless steel grades
1.4852-MA properties
Typical room-temperature values for 1.4852-MA; 20 are specific to this condition. Other listed values are 1.4852 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4852-MA has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,330°C (2,426 °F).
Mechanical13
1.4852-MA has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 74% of stainless steel grades. Elongation at break is 10% and the elastic modulus is 180 GPa (26.1 Msi).
Thermal5
1.4852-MA is rated for continuous service to 1,120°C (2,048 °F). It conducts heat at 13 W/m·K (7.51 BTU/hr·ft·°F), worse than 85% of stainless steel grades. Thermal expansion is 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
1.4852-MA conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 59% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4852-MA takes about 90 MJ of energy and emits 7 kg of CO₂ — more than 94% of stainless steel grades. Typical recycled content is 60%.
Manufacturability8
1.4852-MA's machinability is poor (21/100, worse than 97% of stainless steel grades); weldability fair (48/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4852-MA
Is 1.4852 easy to machine?
Hard interdendritic carbides and severe work hardening — use rigid setups, carbide/ceramic inserts, low speed with heavy positive feed and flood coolant; ID boring of centrifugal tubes is the normal finishing operation.
Can 1.4852 be welded?
GTAW/SMAW with matching HP-Nb filler, preheat generally not required but interpass temperature must be controlled; aged or carburized ex-service tubes need buttering/decarburized-layer removal to avoid hot cracking.
Can 1.4852 be formed, bent or molded?
Cast only (centrifugal for tubes, sand/investment for fittings); no cold or hot forming — geometry is achieved in the mould and by machining.
What surface finishes work on 1.4852?
Shot blasting plus ID machining/honing; no plating or anodizing — the protective Cr₂O₃/SiO₂ scale forms in service.
1.4852 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CASTM A297 HP allows up to 0.75 % | 0.35 – 0.45 | 0.4 |
| Siraises carburization resistance | 1 – 2.5 | 1.6 |
| Mn | ≤ 2 | 1 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 24 – 27 | 25.5 |
| Ni | 33 – 36 | 34.5 |
| Nbprimary MC carbide former, creep strengthening | 0.8 – 1.8 | 1.3 |
| Fe | balance | — |
1.4852-MA — frequently asked
What is 1.4852-MA used for?
1.4852-MA is typically used for ethylene furnace radiant tubes, return bends and fittings for cracking furnaces and high-temperature process piping supports. In short: highest creep strength cast; carburization-resistant HP-Nb; 1100 °C tube grade.
What is the yield strength of 1.4852-MA?
1.4852-MA has a typical yield strength of 285 MPa (41.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 74% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 1.4852-MA easy to machine?
Not especially — machinability is rated poor (21/100, worse than 97% of stainless steel grades). Hard interdendritic carbides and severe work hardening — use rigid setups, carbide/ceramic inserts, low speed with heavy positive feed and flood coolant; ID boring of centrifugal tubes is the normal finishing operation.
Can 1.4852-MA be welded?
With care — weldability is rated fair (48/100). GTAW/SMAW with matching HP-Nb filler, preheat generally not required but interpass temperature must be controlled; aged or carburized ex-service tubes need buttering/decarburized-layer removal to avoid hot cracking.
What surface finishes work on 1.4852-MA?
Shot blasting plus ID machining/honing; no plating or anodizing — the protective Cr₂O₃/SiO₂ scale forms in service.
Can 1.4852-MA be formed, bent or molded?
Cast only (centrifugal for tubes, sand/investment for fittings); no cold or hot forming — geometry is achieved in the mould and by machining.
What is the maximum service temperature of 1.4852-MA?
1.4852-MA is rated for continuous use to about 1,120°C (2,048 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4852 AC-CENT and 1.4852 Aged?
AC-CENT is the default condition — standard supply condition for pyrolysis/reformer radiant tubes — fine columnar structure, best creep-rupture life. Aged: reference condition for repair, re-weld and remaining-life assessment of used furnace tubes — carbide coarsening raises hardness and destroys room-temperature ductility. Yield strength is 270 MPa in AC-CENT versus 300 MPa in Aged.
Sources
- EN 10295 — Heat resistant steel castings — CEN (2002)
- ASTM A297/A297M — Steel Castings, Iron-Chromium-Nickel, Heat Resistant, for General Application — ASTM (2019)
- ASTM A608/A608M — Centrifugally Cast Iron-Chromium-Nickel High-Alloy Tubing for Pressure Application at High Temperatures — ASTM (2018)
- Centralloy / HP-Nb furnace tube alloy data — Schmidt + Clemens (2021)
- Manaurite HP-type reformer and cracking tube alloys — Manoir Industries (2019)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys (heat-resistant castings) — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.