Stainless Steel
Stainless Steel EN 1.4852
Properties, tempers, machining, finishes and uses — values shown for the AC-CENT condition.
EN 1.4852 (GX40NiCrSiNb35-26, ASTM A297 Grade HP-Nb, UNS J95709) is a niobium-stabilized 35Ni-26Cr cast heat-resistant steel developed for high creep-rupture strength and carburization resistance up to about 1100 °C.
Reference datasheet — EN 1.4852 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
What is EN 1.4852?
EN 1.4852 (GX40NiCrSiNb35-26, ASTM A297 Grade HP-Nb, UNS J95709) is a niobium-stabilized 35Ni-26Cr cast heat-resistant steel developed for high creep-rupture strength and carburization resistance up to about 1100 °C. It is used mainly as centrifugally cast pyrolysis tubes and statically cast return bends and fittings. Typical values are 270 MPa yield, 500 MPa tensile, 11 % elongation and 190 HB, with machinability rated 22/100 because of hard interdendritic carbides. Supply is castings only and the alloy embrittles after ageing; 1.4848 (HK40) is the lower-cost choice where creep demands are lower. EN 1.4852 has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 67% of stainless steel grades. It melts at 1,330°C (2,426 °F). EN 1.4852 has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 79% of stainless steel grades. Elongation at break is 11% and the elastic modulus is 180 GPa (26.1 Msi).
What is EN 1.4852 used for?
- ethylene furnace radiant tubes
- return bends and fittings for cracking furnaces
- high-temperature process piping supports
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 96% 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 — 11%, worse than 96% of stainless steel grades
- High embodied carbon — 7 kg CO₂/kg, worse than 96% of stainless steel grades
- Difficult to machine — 22/100, worse than 95% of stainless steel grades
EN 1.4852 properties
Typical room-temperature values for EN 1.4852-AC-CENT (standard supply condition for pyrolysis/reformer radiant tubes — fine columnar structure, best creep-rupture life), compiled from standards, handbooks and producer data. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher. Other conditions have their own pages: see tempers.
Physical3
EN 1.4852 has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 67% of stainless steel grades. It melts at 1,330°C (2,426 °F).
Mechanical13
EN 1.4852 has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 79% of stainless steel grades. Elongation at break is 11% and the elastic modulus is 180 GPa (26.1 Msi).
Thermal5
EN 1.4852 is rated for continuous service to 1,100°C (2,012 °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
EN 1.4852 conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 53% of stainless steel grades.
Sustainability4
Producing a kilogram of EN 1.4852 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
EN 1.4852's machinability is poor (22/100, worse than 95% of stainless steel grades); weldability fair (50/100); formability not recommended (5/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
EN 1.4852 tempers and conditions
EN 1.4852 is supplied in 4 conditions, each with its own property set. Open one for its full datasheet. AC-CENT is what FabDigit quotes unless the drawing says otherwise.
- AC-CENTDefaultStandard supply condition for pyrolysis/reformer radiant tubes — fine columnar structure, best creep-rupture life.270 MPa yield · 190 HB
- AgedReference condition for repair, re-weld and remaining-life assessment of used furnace tubes — carbide coarsening raises hardness and destroys room-temperature ductility.300 MPa yield · 220 HB
2 further conditions are listed below with a summary only.
| Condition | 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 | — |
As-cast, statically (sand/investment) cast fittings | Choose for return bends, headers, manifolds and complex shapes; coarser grain and slightly lower strength/ductility than centrifugal tube. | 250 | 460 | 8 | 185 HB | — |
HP-Nb micro-alloyed (Nb + Ti/Zr/rare-earth modified) | Pick when maximum creep-rupture life and carburization/coking resistance are required for long-campaign ethylene coils. | 285 | 520 | 10 | 195 HB | — |
Thermally aged / service-exposed (e.g. 1000 h at 850–1000 °C) | 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 | — |
Working with EN 1.4852
Is EN 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 EN 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 EN 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.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. EN 1.4852 is highlighted; hover a dot for its name, or open the interactive family chart.
EN 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 | — |
What surface finishes work on EN 1.4852?
Shot blasting plus ID machining/honing; no plating or anodizing — the protective Cr₂O₃/SiO₂ scale forms in service.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing.
Passivation
- Pickling
Plating
- Electroless Nickel (EN)
- Gold Plating
- Hard Chrome Plating
- Silver Plating
Organic Coating
- Epoxy Coating
Thermal Spray
- Plasma Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel EN 1.4852 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J95709
- ASTM
- A297 Grade HP-Nb
- EN / DIN / Werkstoff-Nr.
- 1.4852GX40NiCrSiNb35-26
- Also called
- HP-Nb
How much does EN 1.4852 cost?
EN 1.4852 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
EN 1.4852 — frequently asked
What is EN 1.4852 used for?
EN 1.4852 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 EN 1.4852?
EN 1.4852 has a typical yield strength of 270 MPa (39.2 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 79% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is EN 1.4852 easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% 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 EN 1.4852 be welded?
With care — weldability is rated fair (50/100). 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 EN 1.4852?
Shot blasting plus ID machining/honing; no plating or anodizing — the protective Cr₂O₃/SiO₂ scale forms in service.
Can EN 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 is the maximum service temperature of EN 1.4852?
EN 1.4852 is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between EN 1.4852 AC-CENT and EN 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.
How much does EN 1.4852 cost?
EN 1.4852 is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.