Steel 45SiCrV6-2 +AC (Spheroidize annealed)
Heat-treated state
EN 45SiCrV6-2
Softest supply condition — choose for cold heading, deep cold forming or heavy chip-removal before hardening.
Values for the +AC condition
Other 45SiCrV6-2 tempers and conditions
45SiCrV6-2 is listed in 9 conditions; see the grade overview at 45SiCrV6-2.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ACThis page Spheroidize annealed | Softest supply condition — choose for cold heading, deep cold forming or heavy chip-removal before hardening. | 420 | 700 | 18 | 205 HB | — |
Annealed | Pick for machining, cold forming or straightening of bar before the final hardening operation. | 450 | 750 | 15 | 225 HB | — |
Treated for high shearability | Choose when bar or coil must be cold-sheared or cropped into blanks without cracking, prior to hot forming and hardening. | 470 | 780 | 14 | 21 HRC | 7 % IACS |
Supplied to the standard hardenability band | Order this when the end-quench (Jominy) response must be guaranteed within the normal H-band; usually delivered soft-annealed for later hardening. | 470 | 780 | 14 | 58 HRC | 7 % IACS |
Supplied to the restricted (narrow) hardenability band | Choose for high-volume heat-treated springs where scatter of as-quenched core hardness and distortion must be minimised. | 470 | 780 | 14 | 59 HRC | 7.5 % IACS |
Hot rolled | Cheapest supply form for forging shops that will re-austenitise and harden the part anyway. | 600 | 1,000 | 11 | 31 HRC | 7 % IACS |
Cold drawn | Choose for close-tolerance, bright bar used in torsion bars and clamping parts machined before hardening. | 800 | 950 | 8 | 29 HRC | 7 % IACS |
+QTDefault Quenched and tempered | Standard finished spring condition: oil-quenched from ~870 °C and tempered ~400–480 °C for maximum elastic limit and fatigue life. | 1,500 | 1,700 | 7 | 50 HRC | — |
Oil hardened and tempered spring wire/strip | Pre-hardened wire for coiling of valve-quality and suspension springs; only low-temperature stress relief after forming. | 1,750 | 1,950 | 6 | 54 HRC | — |
What is 45SiCrV6-2 +AC?
45SiCrV6-2 +AC is 45SiCrV6-2 heat treated to +AC — softest supply condition — choose for cold heading, deep cold forming or heavy chip-removal before hardening. 45SiCrV6-2 +AC has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 53% of steel grades. Elongation at break is 18% and the elastic modulus is 206 GPa (29.9 Msi). 45SiCrV6-2 +AC 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 is the default condition FabDigit quotes; +AC is available on request or by drawing note.
Limitations
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 86% of steel grades
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
45SiCrV6-2 +AC properties
Typical room-temperature values for 45SiCrV6-2 +AC; 12 are specific to this condition. Other listed values are 45SiCrV6-2 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
45SiCrV6-2 +AC 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
45SiCrV6-2 +AC has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 53% of steel grades. Elongation at break is 18% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
45SiCrV6-2 +AC is rated for continuous service to 250°C (482 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
45SiCrV6-2 +AC conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 45SiCrV6-2 +AC takes about 30 MJ of energy and emits 2.1 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability6
45SiCrV6-2 +AC's machinability is good (58/100, better than 75% of steel grades); weldability poor (25/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 45SiCrV6-2 +AC
Is 45SiCrV6-2 easy to machine?
Machine only in the +A/+AC condition (≈200–250 HB) with coated carbide; in +QT at ~50 HRC use CBN/ceramic hard-turning or grinding.
Can 45SiCrV6-2 be welded?
Not recommended — high carbon equivalent means quench cracking; if unavoidable, preheat 300–400 °C, low-hydrogen consumables and immediate post-weld temper.
Can 45SiCrV6-2 be formed, bent or molded?
Hot form/coil at 850–950 °C or cold form in the spheroidized state; harden from ~860–880 °C in oil and temper 400–480 °C to the target spring hardness.
What surface finishes work on 45SiCrV6-2?
Shot-peen springs after tempering for fatigue life; protect with phosphate + oil, zinc-flake or epoxy paint — avoid acid pickling and electroplating without a 200 °C hydrogen bake.
45SiCrV6-2 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 | 0.42 – 0.5 | 0.46 |
| Siraises elastic limit and relaxation resistance | 1.3 – 1.6 | 1.45 |
| Mn | 0.5 – 0.8 | 0.65 |
| Cr | 0.5 – 0.8 | 0.65 |
| Vgrain refinement, carbide strengthening | 0.1 – 0.2 | 0.15 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
45SiCrV6-2 +AC — frequently asked
What is 45SiCrV6-2 +AC used for?
45SiCrV6-2 +AC is typically used for coil and leaf springs, automotive suspension components, high-stress fasteners and elastic clamping elements. In short: high-fatigue Si-Cr-V spring steel; 1500 MPa yield after Q&T; not for welded assemblies.
What is the yield strength of 45SiCrV6-2 +AC?
45SiCrV6-2 +AC has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 45SiCrV6-2 +AC easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machine only in the +A/+AC condition (≈200–250 HB) with coated carbide; in +QT at ~50 HRC use CBN/ceramic hard-turning or grinding.
Can 45SiCrV6-2 +AC be welded?
Not readily — weldability is rated poor (25/100). Not recommended — high carbon equivalent means quench cracking; if unavoidable, preheat 300–400 °C, low-hydrogen consumables and immediate post-weld temper.
What surface finishes work on 45SiCrV6-2 +AC?
Shot-peen springs after tempering for fatigue life; protect with phosphate + oil, zinc-flake or epoxy paint — avoid acid pickling and electroplating without a 200 °C hydrogen bake.
Can 45SiCrV6-2 +AC be formed, bent or molded?
Hot form/coil at 850–950 °C or cold form in the spheroidized state; harden from ~860–880 °C in oil and temper 400–480 °C to the target spring hardness.
What is the maximum service temperature of 45SiCrV6-2 +AC?
45SiCrV6-2 +AC 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 45SiCrV6-2 +QT and 45SiCrV6-2-OT?
+QT is the default condition — standard finished spring condition: oil-quenched from ~870 °C and tempered ~400–480 °C for maximum elastic limit and fatigue life. OT: pre-hardened wire for coiling of valve-quality and suspension springs; only low-temperature stress relief after forming. Yield strength is 1,500 MPa in +QT versus 1,750 MPa in OT.
Sources
- EN 10089 — Hot-rolled steels for quenched and tempered springs — CEN (2002)
- EN 10083-1/-3 — Steels for quenching and tempering (delivery conditions +A, +AC, +S, +QT) — CEN (2006)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (spring steels) — ASM International (1990)
- EN 13906-1 — Cylindrical helical springs, design (E and G values) — CEN (2013)
- European spring-steel bar and wire datasheets (1.8151 / 51CrV4 class) — various mills (2023)
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.