Steel 21CrMoV5-7 +AC (Spheroidize annealed)
Heat-treated state
EN 21CrMoV5-7
Pick for bar or wire that must be cold headed, deep-drilled or heavily machined before the final quench-and-temper.
Values for the +AC condition
Other 21CrMoV5-7 tempers and conditions
21CrMoV5-7 is listed in 5 conditions; see the grade overview at 21CrMoV5-7.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Lowest-hardness stock condition for rough machining or re-forging; requires subsequent Q&T for service. | 420 | 660 | 24 | 14 HRC | 7.5 % IACS |
+ACThis page Spheroidize annealed | Pick for bar or wire that must be cold headed, deep-drilled or heavily machined before the final quench-and-temper. | 450 | 700 | 22 | 215 HB | — |
Normalized | Grain-refining intermediate condition after forging, prior to quench and temper. | 560 | 820 | 17 | 24 HRC | 7.2 % IACS |
+QTDefault Quenched and tempered | Standard supply condition for high-temperature bolts, studs, valve stems and forgings up to ~550 °C service. | 700 | 830 | 18 | 25 HRC | — |
+QT high-strength | Choose for bolt diameters below ~100 mm where the higher Rp0.2 class (≥700 MPa) is specified. | 780 | 880 | 15 | 28 HRC | — |
What is 21CrMoV5-7 +AC?
21CrMoV5-7 +AC is 21CrMoV5-7 heat treated to +AC — pick for bar or wire that must be cold headed, deep-drilled or heavily machined before the final quench-and-temper. 21CrMoV5-7 +AC has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 52% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi). 21CrMoV5-7 +AC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). +QT is the default condition FabDigit quotes; +AC is available on request or by drawing note.
Advantages
- High service temperature — 450°C (842 °F), better than 86% of steel grades
21CrMoV5-7 +AC properties
Typical room-temperature values for 21CrMoV5-7 +AC; 15 are specific to this condition. Other listed values are 21CrMoV5-7 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
21CrMoV5-7 +AC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
21CrMoV5-7 +AC has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 52% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
21CrMoV5-7 +AC is rated for continuous service to 450°C (842 °F). It conducts heat at 39 W/m·K (22.5 BTU/hr·ft·°F), worse than 67% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
21CrMoV5-7 +AC conducts electricity at 7.2 % IACS, worse than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 21CrMoV5-7 +AC takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability7
21CrMoV5-7 +AC's machinability is good (55/100, better than 62% of steel grades); weldability fair (45/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 21CrMoV5-7 +AC
Is 21CrMoV5-7 easy to machine?
Machine in +AC/+A condition where possible; in +QT (≈250 HB) use rigid setups, carbide inserts at 90–140 m/min and generous coolant — vanadium carbides accelerate tool wear.
Can 21CrMoV5-7 be welded?
Weldable with matched Cr-Mo-V or 2.25Cr-1Mo consumables using 250–350 °C preheat/interpass and mandatory PWHT at ~690–720 °C; avoid welding fully tempered bolts.
Can 21CrMoV5-7 be formed, bent or molded?
Forge at 1100–850 °C followed by normalizing; cold heading only in the spheroidized condition, then quench (880–930 °C, oil) and temper 660–720 °C.
What surface finishes work on 21CrMoV5-7?
No natural corrosion protection — use phosphating plus MoS₂/graphite bolt lubricant, aluminizing or nickel plating for high-temperature service; avoid electroplating without hydrogen bake-out.
21CrMoV5-7 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 | 0.17 – 0.25 | 0.21 |
| Si | ≤ 0.35 | 0.25 |
| Mn | 0.4 – 0.8 | 0.6 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| Cr | 1.2 – 1.5 | 1.35 |
| Mo | 0.5 – 0.7 | 0.6 |
| V | 0.25 – 0.35 | 0.3 |
| Niresidual, max | ≤ 0.5 | 0.2 |
| Alacid-soluble, max (grain refining) | ≤ 0.02 | 0.01 |
| Fe | balance | — |
21CrMoV5-7 +AC — frequently asked
What is 21CrMoV5-7 +AC used for?
21CrMoV5-7 +AC is typically used for steam turbine bolts and shafts, high-pressure valve bodies, boiler and pipeline fittings and power plant fasteners. In short: high-temperature bolting steel; creep resistant to 540 °C.
What is the yield strength of 21CrMoV5-7 +AC?
21CrMoV5-7 +AC has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is 21CrMoV5-7 +AC easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in +AC/+A condition where possible; in +QT (≈250 HB) use rigid setups, carbide inserts at 90–140 m/min and generous coolant — vanadium carbides accelerate tool wear.
Can 21CrMoV5-7 +AC be welded?
With care — weldability is rated fair (45/100). Weldable with matched Cr-Mo-V or 2.25Cr-1Mo consumables using 250–350 °C preheat/interpass and mandatory PWHT at ~690–720 °C; avoid welding fully tempered bolts.
What surface finishes work on 21CrMoV5-7 +AC?
No natural corrosion protection — use phosphating plus MoS₂/graphite bolt lubricant, aluminizing or nickel plating for high-temperature service; avoid electroplating without hydrogen bake-out.
Can 21CrMoV5-7 +AC be formed, bent or molded?
Forge at 1100–850 °C followed by normalizing; cold heading only in the spheroidized condition, then quench (880–930 °C, oil) and temper 660–720 °C.
What is the maximum service temperature of 21CrMoV5-7 +AC?
21CrMoV5-7 +AC is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10269 — Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties — CEN (2013)
- EN 10222-2 — Steel forgings for pressure purposes: ferritic and martensitic steels for elevated temperature — CEN (2017)
- EN 10269 / DIN 17240 legacy data for 21CrMoV5-7 (1.7709) — DIN (1976)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Cr-Mo-V bolting steel 1.7709 bar/forging datasheet — European special steel producers (e.g. Böhler/Saarstahl-type data) (2022)
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.