Steel 28Mn6 +NT (Normalized and tempered)
Heat-treated state
EN 28Mn6
Normalize plus a stress-relieving temper for dimensionally stable, tough large sections where full quenching is impractical.
Values for the +NT condition
Other 28Mn6 tempers and conditions
28Mn6 is listed in 8 conditions; see the grade overview at 28Mn6.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest supply condition for heavy machining, cold forming or before final heat treatment. | 330 | 580 | 22 | 190 HB | 46 W/m·K |
+NTThis page Normalized and tempered | Normalize plus a stress-relieving temper for dimensionally stable, tough large sections where full quenching is impractical. | 365 | 660 | 19 | 195 HB | — |
Normalized | Uniform fine-grained ferrite/pearlite for weldments and moderate-duty parts that will not be quenched. | 370 | 680 | 18 | 200 HB | — |
+QT | Heavy-forging class; the Mn addition keeps core properties acceptable where plain C45 would fall short. | 380 | 625 | 18 | 185 HB | — |
+QT | Property class for medium-heavy forgings; mass effect lowers strength but toughness stays high. | 430 | 675 | 17 | 15 HRC | — |
+QTDefault Quenched and tempered | Standard commercial condition: best strength/toughness balance for shafts, flanges and forgings of medium section. | 540 | 780 | 16 | 21 HRC | — |
Cold drawn | Cold-drawn bright bar for close-tolerance shafts and automatic-lathe work without further heat treatment. | 560 | 720 | 9 | 215 HB | — |
+QT | Highest strength class of the grade; use for thin bars and small forgings where 800–950 MPa is required. | 620 | 870 | 14 | 26 HRC | — |
What is 28Mn6 +NT?
28Mn6 +NT is 28Mn6 heat treated to +NT — normalize plus a stress-relieving temper for dimensionally stable, tough large sections where full quenching is impractical. 28Mn6 +NT has a yield strength of 365 MPa (52.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 71% of steel grades. Elongation at break is 19% and the elastic modulus is 210 GPa (30.5 Msi). 28Mn6 +NT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). +QT is the default condition FabDigit quotes; +NT is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Low fracture toughness — 58 MPa·√m (52.8 ksi·√in), worse than 80% of steel grades
28Mn6 +NT properties
Typical room-temperature values for 28Mn6 +NT; 15 are specific to this condition. Other listed values are 28Mn6 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
28Mn6 +NT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
28Mn6 +NT has a yield strength of 365 MPa (52.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 71% of steel grades. Elongation at break is 19% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
28Mn6 +NT is rated for continuous service to 425°C (797 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
28Mn6 +NT conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 28Mn6 +NT takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
28Mn6 +NT's machinability is good (58/100, better than 75% of steel grades); weldability fair (50/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 28Mn6 +NT
Is 28Mn6 easy to machine?
Machine in +A or +N (≤220 HB) for best tool life; in +QT (~235 HB) use coated carbide, 120–180 m/min, rigid setups and generous coolant.
Can 28Mn6 be welded?
CEV ≈ 0.55–0.65: preheat 150–250 °C, use low-hydrogen consumables and stress-relieve/temper at 550–650 °C after welding.
Can 28Mn6 be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold bending only in +A/+N condition with generous radii — +QT bar is essentially non-formable.
What surface finishes work on 28Mn6?
No anodizing; protect by painting, phosphating, black oxide, zinc or hard-chrome plating; nitriding or induction hardening can raise surface wear resistance.
28Mn6 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 |
|---|---|---|
| CEN 10083-2 heat analysis | 0.25 – 0.32 | 0.28 |
| Si | ≤ 0.4 | 0.25 |
| Mnhardenability booster | 1.3 – 1.65 | 1.45 |
| P | ≤ 0.04 | 0.02 |
| Slower S grades (+S variants) available for cleanliness | ≤ 0.04 | 0.02 |
| Crresidual | ≤ 0.4 | 0.15 |
| Moresidual | ≤ 0.1 | 0.03 |
| Niresidual; Cr+Mo+Ni ≤ 0.63 | ≤ 0.4 | 0.15 |
| Fe | balance | — |
28Mn6 +NT — frequently asked
What is 28Mn6 +NT used for?
28Mn6 +NT is typically used for crankshafts, large forgings, gear blanks and flanges. In short: deeper hardenability than C35E; large-section Q&T forgings; no Cr-Mo alloy content.
What is the yield strength of 28Mn6 +NT?
28Mn6 +NT has a typical yield strength of 365 MPa (52.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 71% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 28Mn6 +NT easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machine in +A or +N (≤220 HB) for best tool life; in +QT (~235 HB) use coated carbide, 120–180 m/min, rigid setups and generous coolant.
Can 28Mn6 +NT be welded?
With care — weldability is rated fair (50/100). CEV ≈ 0.55–0.65: preheat 150–250 °C, use low-hydrogen consumables and stress-relieve/temper at 550–650 °C after welding.
What surface finishes work on 28Mn6 +NT?
No anodizing; protect by painting, phosphating, black oxide, zinc or hard-chrome plating; nitriding or induction hardening can raise surface wear resistance.
Can 28Mn6 +NT be formed, bent or molded?
Hot forge 1100–850 °C then normalize; cold bending only in +A/+N condition with generous radii — +QT bar is essentially non-formable.
What is the maximum service temperature of 28Mn6 +NT?
28Mn6 +NT is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10083-2 — Steels for quenching and tempering, Part 2: Non-alloy steels — CEN (2006)
- EN 10083-1 — General technical delivery conditions — CEN (2006)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, 31st ed. — Industrial Press (2020)
- GB/T 699 / GB/T 3077 (30Mn2 comparison) — SAC (2015)
- Mysteel / SMM — Mysteel (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.