Stainless Steel 1.4634
EN 1.4634
1.4634 (X2CrAlSiNb18) is a niobium-stabilized 18% Cr ferritic stainless alloyed with aluminium and silicon for oxidation and thermal-fatigue resistance in automotive exhaust hot ends.
Reference datasheet — 1.4634 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 1.4634?
1.4634 (X2CrAlSiNb18) is a niobium-stabilized 18% Cr ferritic stainless alloyed with aluminium and silicon for oxidation and thermal-fatigue resistance in automotive exhaust hot ends. It is chosen for welded exhaust assemblies that must survive service to 950 °C without the cost of austenitic grades, and is supplied as 2B, 2D and 2R cold-rolled sheet, 1D hot-rolled plate and annealed tube. Typical properties are 310 MPa yield, 480 MPa tensile, 26% elongation and 170 HB (85 HRB). Deep-drawability is limited (formability score 58) and room-temperature toughness is low after welding; 1.4736 (18SR) covers higher temperatures. 1.4634 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,480°C (2,696 °F). 1.4634 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 26% and the elastic modulus is 220 GPa (31.9 Msi).
What is 1.4634 used for?
- exhaust manifolds
- catalytic converter shells
- muffler components
Advantages
- Low embodied carbon — 3.4 kg CO₂/kg, better than 91% of stainless steel grades
- High service temperature — 950°C (1,742 °F), better than 86% of stainless steel grades
- Conducts heat well — 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades
- High electrical conductivity — 2.7 % IACS, better than 78% of stainless steel grades
Limitations
- Hard to polish — 60/100, worse than 80% of stainless steel grades
- Needs corrosion protection — 50/100, worse than 78% of stainless steel grades
1.4634 properties
Typical room-temperature values; bars are the position among stainless steel grades.
Physical3
1.4634 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,480°C (2,696 °F).
Mechanical13
1.4634 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 26% and the elastic modulus is 220 GPa (31.9 Msi).
Thermal6
1.4634 is rated for continuous service to 950°C (1,742 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
1.4634 conducts electricity at 2.7 % IACS, better than 78% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4634 takes about 53 MJ of energy and emits 3.4 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 65%.
Manufacturability7
1.4634's machinability is fair (42/100, better than 79% of stainless steel grades); weldability very good (70/100); formability good (58/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. 1.4634 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1.4634
Is 1.4634 easy to machine?
Machines like 430/441 — low-carbon and slightly gummy; use sharp positive-rake carbide, rigid setups, moderate speed with heavy coolant to avoid built-up edge and work hardening.
Can 1.4634 be welded?
Weldable by TIG/MIG/laser/resistance without post-weld annealing thanks to Nb stabilization; keep heat input low to limit HAZ grain coarsening, use Ar-only shielding (avoid N₂/CO₂-rich gas) and 309L/430Nb-type fillers or matching wire.
Can 1.4634 be formed, bent or molded?
Good bendability and roll-forming; deep drawing is more limited than austenitic stainless — allow larger radii, watch for ridging/roping, and expect low springback relative to 304.
1.4634 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 |
|---|---|---|
| Cextra-low carbon | ≤ 0.03 | 0.02 |
| Siraises scaling resistance | 0.7 – 1.3 | 1 |
| Mn | ≤ 1 | 0.4 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.02 | 0 |
| Cr | 17 – 18.5 | 17.8 |
| Alforms protective Al-rich oxide at high temperature | 0.7 – 1.3 | 1 |
| Nbstabilizer, Nb ≥ 12×(C+N); improves high-temperature strength | 0.3 – 0.6 | 0.45 |
| N | ≤ 0.03 | 0.02 |
| Fe | balance |
What surface finishes work on 1.4634?
Pickle and passivate after welding to restore the chromium/aluminium oxide film; can be shot-blasted or brushed, and aluminized or ceramic-coated for extended service above 900 °C — anodizing is not applicable.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 1.4634 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- X2CrAlSiNb18
How much does 1.4634 cost?
1.4634 is a standard-cost stainless steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
1.4634 — frequently asked
What is 1.4634 used for?
1.4634 is typically used for exhaust manifolds, catalytic converter shells and muffler components. In short: exhaust hot-end ferritic; stabilized to 950 °C; alumina-forming oxide layer.
What is the yield strength of 1.4634?
1.4634 has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 63% of stainless steel grades.
Is 1.4634 easy to machine?
Not especially — machinability is rated fair (42/100, better than 79% of stainless steel grades). Machines like 430/441 — low-carbon and slightly gummy; use sharp positive-rake carbide, rigid setups, moderate speed with heavy coolant to avoid built-up edge and work hardening.
Can 1.4634 be welded?
Yes — weldability is rated very good (70/100). Weldable by TIG/MIG/laser/resistance without post-weld annealing thanks to Nb stabilization; keep heat input low to limit HAZ grain coarsening, use Ar-only shielding (avoid N₂/CO₂-rich gas) and 309L/430Nb-type fillers or matching wire.
What surface finishes work on 1.4634?
Pickle and passivate after welding to restore the chromium/aluminium oxide film; can be shot-blasted or brushed, and aluminized or ceramic-coated for extended service above 900 °C — anodizing is not applicable.
Can 1.4634 be formed, bent or molded?
Good bendability and roll-forming; deep drawing is more limited than austenitic stainless — allow larger radii, watch for ridging/roping, and expect low springback relative to 304.
What is the maximum service temperature of 1.4634?
1.4634 is rated for continuous use to about 950°C (1,742 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 1.4634 cost?
1.4634 is a standard-cost stainless steel ($$), cheaper than about 71% 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 10088-1/-2 Stainless steels — list of grades and technical delivery conditions for sheet/plate/strip — CEN (2014)
- EN 10028-7 / EN 10095 heat-resisting steels and nickel alloys (oxidation limits for Al/Si-alloyed ferritics) — CEN (2016)
- Ferritic stainless steels for automotive exhaust systems (18%Cr stabilized and Al-alloyed grades) — Aperam / Outokumpu (2022)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
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.