Steel 45SCD6-HR (Hot rolled)
Supply condition
EN 45SCD6
Mill supply form for spring makers who do their own annealing and hardening.
Values for the HR condition
Other 45SCD6 tempers and conditions
45SCD6 is listed in 8 conditions; see the grade overview at 45SCD6.
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 |
HRThis page 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-HR?
45SCD6-HR is 45SCD6 supplied in the HR condition — mill supply form for spring makers who do their own annealing and hardening. 45SCD6-HR has a yield strength of 640 MPa (92.8 ksi) and a tensile strength of 1,020 MPa (148 ksi) — stronger than 79% of steel grades. Elongation at break is 12% and the elastic modulus is 206 GPa (29.9 Msi). 45SCD6-HR 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). QT-1800 is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- High strength — 640 MPa (92.8 ksi), better than 79% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
- Difficult to weld — 22/100, worse than 81% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
- Low electrical conductivity — 6 % IACS, worse than 78% of steel grades
45SCD6-HR properties
Typical room-temperature values for 45SCD6-HR; 22 are specific to this condition. Other listed values are 45SCD6 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
45SCD6-HR 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-HR has a yield strength of 640 MPa (92.8 ksi) and a tensile strength of 1,020 MPa (148 ksi) — stronger than 79% of steel grades. Elongation at break is 12% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
45SCD6-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
45SCD6-HR conducts electricity at 6 % IACS, worse than 78% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 45SCD6-HR 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-HR's machinability is fair (38/100, worse than 80% of steel grades); weldability poor (22/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 45SCD6-HR
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.
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.
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 | — |
45SCD6-HR — frequently asked
What is 45SCD6-HR used for?
45SCD6-HR 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-HR?
45SCD6-HR has a typical yield strength of 640 MPa (92.8 ksi) and a tensile strength of 1,020 MPa (148 ksi) — stronger than 79% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 45SCD6-HR easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% 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-HR be welded?
Not readily — weldability is rated poor (22/100). 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-HR?
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-HR 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-HR?
45SCD6-HR is rated for continuous use to about 400°C (752 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.