Steel En52
En52 is a martensitic chromium-silicon high-temperature valve steel from the BS 970 family, supplied annealed, hot rolled, quenched and tempered to 750 or 800 MPa classes, or Q&T and nitrided.
Reference datasheet — En52 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.
Values for the QT750 condition
En52 tempers and conditions
En52 is supplied in 5 conditions, soft to hard. QT750 is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest supply condition for machining or cold straightening before hardening. | 480 | 780 | 22 | 21 HRC | 2.4 % IACS |
Hot rolled | Mill bar or forged valve blanks bought for subsequent hardening and tempering. | 600 | 900 | 18 | 29 HRC | 2.3 % IACS |
Q&T | Choose when maximum ductility/toughness and dimensional stability at high running temperature matter more than strength. | 660 | 900 | 21 | 25 HRC | 2.3 % IACS |
QT750Default Q&T | Standard service condition for exhaust valves and hot bolts — best balance of hot strength, scaling resistance and toughness. | 750 | 1,000 | 17 | 30 HRC | — |
Q&T + gas nitrided valve stem/seat | Surface-treated condition for wear resistance on valve stems and seating faces; core properties as QT750. | 750 | 1,000 | 14 | 30 HRC | 2.3 % IACS |
What is En52?
En52 is a martensitic chromium-silicon high-temperature valve steel from the BS 970 family, supplied annealed, hot rolled, quenched and tempered to 750 or 800 MPa classes, or Q&T and nitrided. It was developed for exhaust valves in internal combustion engines and is used where hot hardness and scuffing resistance matter: the default condition gives 750 MPa yield, 1000 MPa tensile, 17 % elongation and 285 HB (30 HRC), with service to 750 °C. The silicon-rich matrix is abrasive and work-hardens, so machinability is low (score 32); the steel air-hardens and welds poorly, and it forms no useful passive film despite the chromium content. En52 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,420°C (2,588 °F). En52 has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Elongation at break is 17% and the elastic modulus is 215 GPa (31.2 Msi).
What is En52 used for?
- Engine exhaust valves
- Valve stems and seat faces
- High-temperature fasteners
- Furnace and burner hardware
- Exhaust manifold studs and nuts
- Turbocharger linkage pins
- Hot-gas valve guides and bushes
Advantages
- High service temperature — 750°C (1,382 °F), better than 100% of steel grades
- Good corrosion resistance — 35/100, better than 97% of steel grades
- High strength — 750 MPa (109 ksi), better than 84% of steel grades
Limitations
- Low electrical conductivity — 2.3 % IACS, worse than 98% of steel grades
- Poor heat conductor — 23 W/m·K (13.3 BTU/hr·ft·°F), worse than 92% of steel grades
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 90% of steel grades
- Difficult to machine — 32/100, worse than 87% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
En52 properties
Typical room-temperature values for En52-QT750; bars are the position among steel grades.
Physical3
En52 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
En52 has a yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Elongation at break is 17% and the elastic modulus is 215 GPa (31.2 Msi).
Thermal6
En52 is rated for continuous service to 750°C (1,382 °F). It conducts heat at 23 W/m·K (13.3 BTU/hr·ft·°F), worse than 92% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
En52 conducts electricity at 2.3 % IACS, worse than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), better than 97% of steel grades.
Sustainability4
Producing a kilogram of En52 takes about 36 MJ of energy and emits 2.6 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 30%.
Manufacturability8
En52's machinability is poor (32/100, worse than 87% of steel grades); weldability poor (25/100); formability poor (20/100).
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 steel family
Yield strength against density for every steel grade FabDigit runs. En52 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with En52
Is En52 easy to machine?
Machine in the annealed or high-tempered condition with rigid setups, sharp carbide tooling and generous coolant; the Si-rich matrix is abrasive and work-hardens, so keep speeds moderate and feeds steady.
Can En52 be welded?
Poor weldability — air-hardening martensitic steel; if unavoidable use 300–400 °C preheat, matching or austenitic filler, and temper immediately after welding, otherwise expect HAZ cracking.
Can En52 be formed, bent or molded?
Hot-work only: forge/extrude valve blanks at 1050–1150 °C and finish above 900 °C, then slow cool or anneal; cold forming is impractical.
En52 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 | 0.4 – 0.5 | 0.45 |
| Sihigh Si for scaling resistance | 3 – 3.75 | 3.3 |
| Mn | 0.2 – 0.6 | 0.4 |
| Cr | 7.5 – 9.5 | 8.5 |
| Niresidual | ≤ 0.5 | 0.2 |
| Moresidual | ≤ 0.3 | |
| P | ≤ 0.04 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on En52?
Nitride or chromize stems and seat faces for wear and scuffing resistance; the surface polishes well but has no useful passive film, so oil, phosphate or plate parts exposed to moisture.
Surface treatments FabDigit runs on 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).
Organic Coating
Black / Phosphate
Thermal Spray
How much does En52 cost?
En52 is a standard-cost 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.
En52 — frequently asked
What is En52 used for?
En52 is typically used for engine exhaust valves, valve stems and seat faces, high-temperature fasteners, furnace and burner hardware, exhaust manifold studs and nuts and turbocharger linkage pins. In short: 750 °C valve steel; highest service temperature here; hot hardness, abrasive to cut.
What is the yield strength of En52?
En52 has a typical yield strength of 750 MPa (109 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 84% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is En52 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 87% of steel grades). Machine in the annealed or high-tempered condition with rigid setups, sharp carbide tooling and generous coolant; the Si-rich matrix is abrasive and work-hardens, so keep speeds moderate and feeds steady.
Can En52 be welded?
Not readily — weldability is rated poor (25/100). Poor weldability — air-hardening martensitic steel; if unavoidable use 300–400 °C preheat, matching or austenitic filler, and temper immediately after welding, otherwise expect HAZ cracking.
What surface finishes work on En52?
Nitride or chromize stems and seat faces for wear and scuffing resistance; the surface polishes well but has no useful passive film, so oil, phosphate or plate parts exposed to moisture.
Can En52 be formed, bent or molded?
Hot-work only: forge/extrude valve blanks at 1050–1150 °C and finish above 900 °C, then slow cool or anneal; cold forming is impractical.
What is the maximum service temperature of En52?
En52 is rated for continuous use to about 750°C (1,382 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between En52-QT750 and En52-A?
QT750 is the default condition — standard service condition for exhaust valves and hot bolts — best balance of hot strength, scaling resistance and toughness. A: softest supply condition for machining or cold straightening before hardening. Yield strength is 750 MPa in QT750 versus 480 MPa in A.
How much does En52 cost?
En52 is a standard-cost 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
- BS 970 (En-series / 401S45 valve steel) — BSI (1955)
- DIN 17480 / EN 10090 — Valve steels for internal combustion engines (X45CrSi9-3, 1.4718) — DIN/CEN (1998)
- GB/T 1222 — Spring and valve steels (4Cr9Si2) — SAC (2016)
- JIS G 4311 — Heat-resisting steel bars (SUH1) — JISC (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- 1.4718 / X45CrSi9-3 valve steel bar datasheet — European specialty steel producers (2020)
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.