Steel 45SCD6
EN 45SCD6
45SCD6 is an AFNOR silicon-chromium-molybdenum alloy spring steel, quenched and tempered to very high strength for fatigue-loaded parts.
Reference datasheet — 45SCD6 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 QT-1800 condition
45SCD6 tempers and conditions
45SCD6 is supplied in 8 conditions, soft to hard. QT-1800 is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Supply condition for machining, cold coiling of heavy wire or upsetting before final hardening. | 460 | 780 | 18 | 225 HB | — |
Normalized | Grain-refined intermediate condition after hot forging, before quench and temper. | 620 | 980 | 13 | 30 HRC | 6 % IACS |
Hot rolled | Mill supply form for spring makers who do their own annealing and hardening. | 640 | 1,020 | 12 | 31 HRC | 6 % IACS |
Cold drawn | Close-tolerance, decarb-free bar for torsion bars and machined spring components before hardening. | 800 | 950 | 9 | 30 HRC | 6 % IACS |
Q&T ~1500 MPa | Tougher temper for thick torsion bars and stabiliser bars where impact and notch tolerance matter. | 1,330 | 1,500 | 10 | 46 HRC | — |
QT-1800Default Q&T ~1800 MPa | Standard hardened-and-tempered spring condition: best balance of elastic limit, relaxation resistance and toughness. | 1,600 | 1,800 | 8 | 51 HRC | — |
Q&T + shot peened (and pre-set) spring | Final production state of coil springs and torsion bars — compressive surface stress lifts fatigue life markedly. | 1,620 | 1,800 | 8 | 51 HRC | 5 % IACS |
Q&T ~2000 MPa | Maximum-strength temper for lightweight high-stress valve and suspension springs; low toughness, very decarb/defect sensitive. | 1,800 | 2,000 | 6 | 54 HRC | — |
What is 45SCD6?
45SCD6 is an AFNOR silicon-chromium-molybdenum alloy spring steel, quenched and tempered to very high strength for fatigue-loaded parts. In the hardened temper it reaches 1600 MPa yield, 1800 MPa tensile, 8 % elongation and 51 HRC, with service limited to 250 °C, and is supplied as annealed, normalized, hot-rolled and cold-drawn bar and wire for coiling or forging. The trade-offs are poor machinability (score 20), no practical weldability on load-carrying parts, no corrosion resistance and sensitivity to decarburisation and hydrogen. 51CrV4/6150 is the common alternative where slightly lower strength is acceptable. 45SCD6 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,420°C (2,588 °F). 45SCD6 has a yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 98% of steel grades. Elongation at break is 8% and the elastic modulus is 206 GPa (29.9 Msi).
What is 45SCD6 used for?
- torsion bars
- heavy springs
- suspension components
Advantages
- High strength — 1,600 MPa (232 ksi), better than 98% of steel grades
Limitations
- Difficult to machine — 20/100, worse than 97% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Limited ductility — 8%, worse than 95% of steel grades
- Limited formability — 10/100, worse than 95% of steel grades
- Low fracture toughness — 40 MPa·√m (36.4 ksi·√in), worse than 92% of steel grades
45SCD6 properties
Typical room-temperature values for 45SCD6-QT-1800; bars are the position among steel grades.
Physical3
45SCD6 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
45SCD6 has a yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 98% of steel grades. Elongation at break is 8% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
45SCD6 is rated for continuous service to 250°C (482 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 73% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
45SCD6 conducts electricity at 5 % IACS, worse than 82% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 45SCD6 takes about 30 MJ of energy and emits 2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability6
45SCD6's machinability is poor (20/100, worse than 97% of steel grades); weldability not recommended (12/100); 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. 45SCD6 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 45SCD6
Is 45SCD6 easy to machine?
Machine only in the annealed condition (~225 HB) with carbide tooling; after quench-and-temper at 48–55 HRC use grinding or CBN, and avoid grinding burns that cause re-tempering or cracks.
Can 45SCD6 be welded?
Not recommended for load-carrying springs — high carbon equivalent gives hard, crack-prone HAZ; if unavoidable, preheat 300–350 °C, low-hydrogen filler and immediate post-weld temper.
Can 45SCD6 be formed, bent or molded?
Hot coil/forge at 900–1050 °C, or cold coil in annealed state then harden (austenitize ~880 °C, oil quench, temper 400–480 °C to target strength); presetting and shot peening are standard finishing steps.
45SCD6 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 |
|---|---|---|
| CAFNOR 45SCD6 ≈ EN 46SiCrMo6 (1.8062) | 0.42 – 0.5 | 0.46 |
| Siraises elastic limit and relaxation resistance | 1.3 – 1.6 | 1.45 |
| Mn | 0.5 – 0.8 | 0.65 |
| Cr | 0.9 – 1.2 | 1.05 |
| Mohardenability + temper resistance | 0.2 – 0.3 | 0.25 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Curesidual limit typical of spring steel practice | ≤ 0.25 | |
| Fe | balance |
What surface finishes work on 45SCD6?
Protect with phosphate + oil, zinc-flake or powder coating; avoid electroplating on the high-strength temper or bake at 190–220 °C within 4 h to relieve hydrogen; control furnace atmosphere to prevent surface decarburisation that kills fatigue life.
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 45SCD6 cost?
45SCD6 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.
45SCD6 — frequently asked
What is 45SCD6 used for?
45SCD6 is typically used for torsion bars, heavy springs and suspension components. In short: 1800 MPa spring steel; high fatigue resistance; not for welded assemblies.
What is the yield strength of 45SCD6?
45SCD6 has a typical yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 98% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 45SCD6 easy to machine?
Not especially — machinability is rated poor (20/100, worse than 97% of steel grades). Machine only in the annealed condition (~225 HB) with carbide tooling; after quench-and-temper at 48–55 HRC use grinding or CBN, and avoid grinding burns that cause re-tempering or cracks.
Can 45SCD6 be welded?
Not readily — weldability is rated not recommended (12/100). Not recommended for load-carrying springs — high carbon equivalent gives hard, crack-prone HAZ; if unavoidable, preheat 300–350 °C, low-hydrogen filler and immediate post-weld temper.
What surface finishes work on 45SCD6?
Protect with phosphate + oil, zinc-flake or powder coating; avoid electroplating on the high-strength temper or bake at 190–220 °C within 4 h to relieve hydrogen; control furnace atmosphere to prevent surface decarburisation that kills fatigue life.
Can 45SCD6 be formed, bent or molded?
Hot coil/forge at 900–1050 °C, or cold coil in annealed state then harden (austenitize ~880 °C, oil quench, temper 400–480 °C to target strength); presetting and shot peening are standard finishing steps.
What is the maximum service temperature of 45SCD6?
45SCD6 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 45SCD6 QT-1800 and 45SCD6-A?
QT-1800 is the default condition — standard hardened-and-tempered spring condition: best balance of elastic limit, relaxation resistance and toughness. A: supply condition for machining, cold coiling of heavy wire or upsetting before final hardening. Yield strength is 1,600 MPa in QT-1800 versus 460 MPa in A.
How much does 45SCD6 cost?
45SCD6 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
- EN 10089 — Hot rolled steels for quenched and tempered springs (46SiCrMo6, 1.8062) — CEN (2002)
- NF A 35-571 — Aciers pour ressorts (désignation AFNOR 45SCD6) — AFNOR (1990)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (Spring Steels) — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Spring steel bar 46SiCrMo6 datasheet — Saarstahl / Ovako (2021)
- EN 13906-1 — Cylindrical helical springs, design and calculation — CEN (2013)
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.