Steel EN41B · temper
Steel EN41B Annealed
Properties of the Annealed condition, compared with the other EN41B tempers.
Choose for rough machining or deep drilling of blanks before hardening and nitriding.
What is EN41B Annealed?
EN41B Annealed is EN41B in the Annealed temper — choose for rough machining or deep drilling of blanks before hardening and nitriding. EN41B Annealed has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 53% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi). EN41B Annealed 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). Q&T is the default condition FabDigit quotes; Annealed is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High service temperature — 450°C (842 °F), better than 86% of steel grades
- Easy to machine — 60/100, better than 83% of steel grades
Limitations
- Difficult to weld — 20/100, worse than 84% of steel grades
EN41B Annealed properties
Typical room-temperature values for EN41B Annealed — 10 properties are specific to this condition; the rest are grade-level values shared by every EN41B temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
EN41B Annealed 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
EN41B Annealed has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 53% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
EN41B Annealed is rated for continuous service to 450°C (842 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), worse than 64% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical2
EN41B Annealed has an electrical resistivity of 2.2×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of EN41B Annealed takes about 34 MJ of energy and emits 2.3 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
EN41B Annealed's machinability is good (60/100, better than 83% of steel grades); weldability poor (20/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other EN41B tempers and conditions
EN41B is also supplied in 5 other conditions. The full side-by-side table is on the EN41B overview.
- Q&TDefaultStandard stocked condition: tough core ready for finish machining and subsequent nitriding.740 MPa yield · 27 HRC
- Q&T-VHighest normally supplied core strength; accept reduced toughness and harder machining.880 MPa yield · 33 HRC
- Q&T-UPick when a stronger core is needed under the nitrided case, e.g. highly loaded shafts.820 MPa yield · 31 HRC
- Q&T+NitridedThe service condition for EN41B: use where extreme surface hardness, scuff and wear resistance with minimal distortion are needed.740 MPa yield · 68 HRC
- AnnealedChoose for rough machining or deep drilling of blanks before hardening and nitriding.450 MPa yield · 200 HB
Working with EN41B Annealed
Is EN41B easy to machine?
Machines like a 30 HRC Cr-Mo steel — rigid setups, coated carbide, moderate speeds; finish-machine before nitriding and leave only 0.02–0.05 mm for lapping afterwards.
Can EN41B be welded?
Effectively non-weldable for structural joints (0.4 %C plus 1.1 %Al); if unavoidable, preheat 300–350 °C, use low-hydrogen consumables and post-weld temper, and never weld nitrided surfaces.
Can EN41B be formed, bent or molded?
Hot forge 1050–1150 °C with slow cooling and a full anneal afterwards; cold forming is not practical in Q&T condition.
What surface finishes work on EN41B?
Gas or plasma nitride 500–530 °C for 900–1100 HV cases (0.2–0.6 mm); remove any brittle white layer by lapping, then oil, phosphate or black-oxide for corrosion protection.
EN41B 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 | 0.35 – 0.45 | 0.4 |
| Si | 0.1 – 0.4 | 0.25 |
| Mn | 0.4 – 0.65 | 0.55 |
| Cr | 1.4 – 1.8 | 1.6 |
| Mo | 0.15 – 0.25 | 0.2 |
| Alforms hard AlN-rich nitrided case | 0.9 – 1.3 | 1.1 |
| P0.05 max in older BS 970 issues | ≤ 0.04 | — |
| S0.05 max in older BS 970 issues | ≤ 0.04 | — |
| Fe | balance | — |
EN41B Annealed — frequently asked
What is EN41B Annealed used for?
EN41B Annealed is typically used for nitrided industrial shafts, gear surfaces and gear shafts, plastic extruder screws and barrels, machine tool spindles, pump shafts and valve stems. In short: high-strength aerospace bar.
What is the yield strength of EN41B Annealed?
EN41B Annealed has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 53% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is EN41B Annealed easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like a 30 HRC Cr-Mo steel — rigid setups, coated carbide, moderate speeds; finish-machine before nitriding and leave only 0.02–0.05 mm for lapping afterwards.
Can EN41B Annealed be welded?
Not readily — weldability is rated poor (20/100). Effectively non-weldable for structural joints (0.4 %C plus 1.1 %Al); if unavoidable, preheat 300–350 °C, use low-hydrogen consumables and post-weld temper, and never weld nitrided surfaces.
What surface finishes work on EN41B Annealed?
Gas or plasma nitride 500–530 °C for 900–1100 HV cases (0.2–0.6 mm); remove any brittle white layer by lapping, then oil, phosphate or black-oxide for corrosion protection.
Can EN41B Annealed be formed, bent or molded?
Hot forge 1050–1150 °C with slow cooling and a full anneal afterwards; cold forming is not practical in Q&T condition.
What is the maximum service temperature of EN41B Annealed?
EN41B Annealed 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.
Can FabDigit make parts in EN41B Annealed?
Yes — EN41B Annealed is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- BS 970-3: Wrought steels — 905M39 (EN41B) — BSI (1991)
- GB/T 3077 — 38CrMoAlA — SAC (2015)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4A: Steel Heat Treating — Nitriding — ASM International (2013)
- Nitriding steel 905M39 / 1.8509-type bar datasheet — Special steel stockholders (2022)
- 38CrMoAlA — Mysteel / 1688 (2025)
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.