Stainless Steel 1.4872 +AT (Solution annealed)
Heat-treated state
EN 1.4872
Softest supply condition, used for hot/warm forming of valve blanks before ageing.
Values for the +AT condition
Other 1.4872 tempers and conditions
1.4872 is listed in 4 conditions; see the grade overview at 1.4872.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ATThis page Solution annealed | Softest supply condition, used for hot/warm forming of valve blanks before ageing. | 400 | 810 | 35 | 22 HRC | — |
+PDefault Solution annealed and precipitation hardened | Standard delivered condition for finished exhaust valves — maximum hot strength and creep resistance. | 640 | 1,030 | 13 | 34 HRC | — |
+P + nitrided | Choose when valve stem wear against the guide and scuffing resistance govern. | 640 | 1,030 | 12 | 34 HRC | 1.9 % IACS |
Precipitation hardened, cold drawn / peeled-ground bar | Bar stock with close diameter tolerance and slightly higher strength for automatic-lathe valve machining. | 750 | 1,100 | 10 | 36 HRC | 1.9 % IACS |
What is 1.4872 +AT?
1.4872 +AT is 1.4872 heat treated to +AT — softest supply condition, used for hot/warm forming of valve blanks before ageing. 1.4872 +AT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 200 GPa (29 Msi). 1.4872 +AT has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,370°C (2,498 °F). +P is the default condition FabDigit quotes; +AT is available on request or by drawing note.
Limitations
- Difficult to weld — 30/100, worse than 88% of stainless steel grades
- Low electrical conductivity — 1.9 % IACS, worse than 84% of stainless steel grades
1.4872 +AT properties
Typical room-temperature values for 1.4872 +AT; 11 are specific to this condition. Other listed values are 1.4872 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4872 +AT has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical14
1.4872 +AT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 35% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1.4872 +AT is rated for continuous service to 760°C (1,400 °F). It conducts heat at 14.5 W/m·K (8.38 BTU/hr·ft·°F), worse than 72% of stainless steel grades. Thermal expansion is 17.5 µm/m·K (9.72 µin/in·°F).
Electrical3
1.4872 +AT conducts electricity at 1.9 % IACS, worse than 84% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 62% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4872 +AT takes about 55 MJ of energy and emits 4.8 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 40%.
Manufacturability8
1.4872 +AT's machinability is poor (26/100, worse than 84% of stainless steel grades); weldability poor (30/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4872 +AT
Is 1.4872 easy to machine?
Tough, strongly work-hardening high-N austenite: use rigid setups, sharp carbide/ceramic inserts, low speed with heavy positive feed and generous coolant to avoid glazing.
Can 1.4872 be welded?
Not a general fusion-weld grade; valves are normally friction (inertia) welded to a martensitic stem, and any fusion repair needs preheat plus post-weld solution treatment to avoid carbide/hot cracking.
Can 1.4872 be formed, bent or molded?
Formed hot (≈1050–1150 °C) by extrusion/upset forging of valve blanks; cold forming is very limited due to high work-hardening rate.
What surface finishes work on 1.4872?
Stems are ground and gas/salt-bath nitrided or chrome-plated; heads may be aluminised or hardfaced with Stellite for seat wear.
1.4872 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 |
|---|---|---|
| C | 0.2 – 0.3 | 0.25 |
| Si | ≤ 0.5 | 0.3 |
| Mn | 8 – 10 | 9 |
| P | ≤ 0.05 | — |
| S | ≤ 0.03 | — |
| Cr | 24 – 26 | 25 |
| Ni | 6 – 8 | 7 |
| Nnitrogen strengthening, key to hot strength | 0.2 – 0.4 | 0.3 |
| Fe | balance | — |
1.4872 +AT — frequently asked
What is 1.4872 +AT used for?
1.4872 +AT is typically used for engine exhaust valves, high-temperature fasteners, turbocharger components and furnace hardware. In short: high-nitrogen valve steel; 800 °C service strength; difficult to machine.
What is the yield strength of 1.4872 +AT?
1.4872 +AT has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 57% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 1.4872 +AT easy to machine?
Not especially — machinability is rated poor (26/100, worse than 84% of stainless steel grades). Tough, strongly work-hardening high-N austenite: use rigid setups, sharp carbide/ceramic inserts, low speed with heavy positive feed and generous coolant to avoid glazing.
Can 1.4872 +AT be welded?
Not readily — weldability is rated poor (30/100). Not a general fusion-weld grade; valves are normally friction (inertia) welded to a martensitic stem, and any fusion repair needs preheat plus post-weld solution treatment to avoid carbide/hot cracking.
What surface finishes work on 1.4872 +AT?
Stems are ground and gas/salt-bath nitrided or chrome-plated; heads may be aluminised or hardfaced with Stellite for seat wear.
Can 1.4872 +AT be formed, bent or molded?
Formed hot (≈1050–1150 °C) by extrusion/upset forging of valve blanks; cold forming is very limited due to high work-hardening rate.
What is the maximum service temperature of 1.4872 +AT?
1.4872 +AT is rated for continuous use to about 760°C (1,400 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10090 — Valve steels and alloys for internal combustion engines — CEN (1998)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys (valve steels) — ASM International (1990)
- Valve steel bar datasheets (X25CrMnNiN25-9-7 / 21-4N type) — Specialty valve-steel producers (2022)
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.