Steel En47
En47 is a BS 970 chromium-vanadium spring steel roughly equivalent to 50CrV4 and 6150, available hot rolled, annealed, spheroidize annealed, normalized, cold drawn, oil-tempered wire, heat-treated strip and in quenched and tempered bands from QT28-32 to QT48-52.
Reference datasheet — En47 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 QT44-48 condition
En47 tempers and conditions
En47 is supplied in 10 conditions, soft to hard. QT44-48 is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Softest condition, used for cold heading, deep drawing or heavy cold forming of blanks. | 400 | 660 | 25 | 11 HRC | 8.5 % IACS |
Solution annealed | Pick for machining, cold bending or blanking of spring blanks before hardening. | 450 | 750 | 20 | 225 HB | — |
Hot rolled | Cheapest mill condition for stock that will be forged or fully heat treated afterwards. | 600 | 950 | 14 | 29 HRC | — |
Normalized | Uniform fine-grain structure after forging; a good base condition before hardening. | 650 | 1,000 | 15 | 31 HRC | — |
Cold drawn | Close tolerance bright bar for machined parts that will be hardened later. | 700 | 860 | 10 | 24 HRC | 7.8 % IACS |
Q&T 28–32 HRC | Tough machinable condition for shafts, tools and lightly loaded torsion members. | 880 | 1,000 | 15 | 30 HRC | — |
Q&T 36–40 HRC | Balanced strength/toughness for torsion bars and medium-duty springs. | 1,120 | 1,250 | 12 | 38 HRC | — |
Q&T 40–44 HRC | Common leaf-spring and heavy coil-spring hardness with useful residual toughness. | 1,270 | 1,400 | 10 | 42 HRC | — |
QT44-48Default Q&T 44–48 HRC | Standard working hardness of En47 springs and torsion bars — best strength/relaxation compromise. | 1,450 | 1,600 | 8 | 46 HRC | — |
Q&T 48–52 HRC | Maximum spring load capacity, chisels and punches; toughness and notch tolerance drop sharply. | 1,620 | 1,800 | 6 | 50 HRC | — |
Supply forms, finishes and certifications
Ways En47 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
OT-WIRE | OT | Supply form |
STRIP-HT | Strip H&T | Supply form |
What is En47?
En47 is a BS 970 chromium-vanadium spring steel roughly equivalent to 50CrV4 and 6150, available hot rolled, annealed, spheroidize annealed, normalized, cold drawn, oil-tempered wire, heat-treated strip and in quenched and tempered bands from QT28-32 to QT48-52. It is chosen for high-duty springs and torsion bars: the default condition reaches 1450 MPa yield, 1600 MPa tensile, 8 % elongation and 425 HB (46 HRC), with a 250 °C maximum service temperature. Machinability (28), weldability (20) and formability (10) are all low, and the bare steel has no corrosion resistance, so forming is done annealed or as pre-tempered strip and wire and the surface must be coated. En47 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). En47 has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,600 MPa (232 ksi) — stronger than 97% of steel grades. Elongation at break is 8% and the elastic modulus is 207 GPa (30 Msi).
What is En47 used for?
- coil springs
- torsion bars
- valve springs
Advantages
- High strength — 1,450 MPa (210 ksi), better than 97% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited ductility — 8%, worse than 95% of steel grades
- Limited formability — 10/100, worse than 95% of steel grades
- Difficult to machine — 28/100, worse than 91% of steel grades
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 90% of steel grades
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
En47 properties
Typical room-temperature values for En47-QT44-48; bars are the position among steel grades.
Physical3
En47 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
En47 has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,600 MPa (232 ksi) — stronger than 97% of steel grades. Elongation at break is 8% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
En47 is rated for continuous service to 250°C (482 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
En47 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of En47 takes about 27 MJ of energy and emits 2.3 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 30%.
Manufacturability7
En47's machinability is poor (28/100, worse than 91% of steel grades); weldability poor (20/100); formability not recommended (10/100).
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. En47 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with En47
Is En47 easy to machine?
Machine in the annealed/spheroidized state (~60 % of 1212); above 40 HRC use carbide or CBN with rigid setups, or finish by grinding.
Can En47 be welded?
Poor weldability (CE ≈ 0.9): preheat 250–350 °C, low-hydrogen consumables, immediate post-weld temper — avoid welding on finished springs.
Can En47 be formed, bent or molded?
Cold form or coil only when annealed or as pre-tempered spring strip/wire; hot form at 950–1100 °C, then harden 830–860 °C oil quench and temper 380–520 °C to the target hardness.
En47 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 | 0.45 – 0.55 | 0.5 |
| Si | 0.1 – 0.35 | 0.25 |
| Mn | 0.5 – 0.8 | 0.65 |
| Cr | 0.9 – 1.2 | 1.05 |
| V0.15 % minimum in BS 970 En47; EN 10089 50CrV4 specifies 0.10–0.25 % | 0.15 – 0.25 | 0.18 |
| P | ≤ 0.04 | |
| Smax (0.025 max for spring quality) | ≤ 0.04 | |
| Fe | balance |
What surface finishes work on En47?
No corrosion resistance bare — shot peen then phosphate + oil, powder coat or zinc plate with 190–220 °C bake to avoid hydrogen embrittlement; decarburised skin must be ground off before service.
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
Equivalent designations
Standards and trade names that resolve to Steel En47 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does En47 cost?
En47 is a budget-cost steel ($), cheaper than about 90% 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.
En47 — frequently asked
What is En47 used for?
En47 is typically used for coil springs, torsion bars and valve springs. In short: high-duty Cr-V spring steel; 50CrV4 / 6150 equivalent; hardest grade in family.
What is the yield strength of En47?
En47 has a typical yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,600 MPa (232 ksi) — stronger than 97% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is En47 easy to machine?
Not especially — machinability is rated poor (28/100, worse than 91% of steel grades). Machine in the annealed/spheroidized state (~60 % of 1212); above 40 HRC use carbide or CBN with rigid setups, or finish by grinding.
Can En47 be welded?
Not readily — weldability is rated poor (20/100). Poor weldability (CE ≈ 0.9): preheat 250–350 °C, low-hydrogen consumables, immediate post-weld temper — avoid welding on finished springs.
What surface finishes work on En47?
No corrosion resistance bare — shot peen then phosphate + oil, powder coat or zinc plate with 190–220 °C bake to avoid hydrogen embrittlement; decarburised skin must be ground off before service.
Can En47 be formed, bent or molded?
Cold form or coil only when annealed or as pre-tempered spring strip/wire; hot form at 950–1100 °C, then harden 830–860 °C oil quench and temper 380–520 °C to the target hardness.
What is the maximum service temperature of En47?
En47 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between En47 QT44-48 and En47-SA?
QT44-48 is the default condition — standard working hardness of En47 springs and torsion bars — best strength/relaxation compromise. SA: softest condition, used for cold heading, deep drawing or heavy cold forming of blanks. Yield strength is 1,450 MPa in QT44-48 versus 400 MPa in SA.
How much does En47 cost?
En47 is a budget-cost steel ($), cheaper than about 90% 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 970-1: Wrought steels for mechanical and allied engineering purposes (En47 / 735A50) — BSI (1991)
- EN 10089: Hot-rolled steels for quenched and tempered springs (50CrV4, 1.8159) — CEN (2002)
- EN 10270-2: Steel wire for mechanical springs — oil hardened and tempered wire — CEN (2011)
- ASTM A689 / SAE J404 (AISI 6150 alloy spring steel) — ASTM / SAE (2015)
- GB/T 1222 (50CrVA) — SAC (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture (spring steels) — ASM International (1996)
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.