Steel 20Mn5
EN 20Mn5
20Mn5 is a carbon-manganese forging steel (1.1133, about 0.20 % C) supplied to EN 10222-2 for pressure-purpose forgings, with A350 Gr.
Reference datasheet — 20Mn5 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +NT condition
20Mn5 tempers and conditions
20Mn5 is supplied in 4 conditions, soft to hard. +NT is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition, used for heavy machining or cold working of forging blanks before final heat treatment. | 260 | 460 | 30 | 135 HB | — |
Normalized | Standard low-cost delivery condition for pressure forgings up to moderate wall thickness; uniform fine ferrite-pearlite structure. | 310 | 520 | 25 | 152 HB | — |
+NTDefault Normalized and tempered | Most commonly stocked pressure-forging condition (flanges, fittings, A350 LF2 equivalent): normalizing plus a tempering/stress-relief cycle for stable properties and good low-temperature toughness. | 320 | 530 | 25 | 155 HB | — |
Quenched and tempered | Choose for thicker sections or when higher proof stress and the best low-temperature Charpy values (e.g. −46 °C service) are required. | 370 | 570 | 24 | 12 HRC | — |
What is 20Mn5?
20Mn5 is a carbon-manganese forging steel (1.1133, about 0.20 % C) supplied to EN 10222-2 for pressure-purpose forgings, with A350 Gr. LF2 and 20MnMo as cross-references. It is specified for flanges, valve bodies and fittings in vessel and piping systems: default-condition properties are 320 MPa yield, 530 MPa tensile, 25 % elongation and about 155 HB (82 HRB), with service to 400 °C and weldability rated 78/100. Conditions on file are +A, +N, +NT and +QT. Cold formability is limited (60/100) and corrosion resistance is negligible (11/100), so coating or lining is required; P355NL2 plate is the usual counterpart where the same duty is met in welded plate form. 20Mn5 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). 20Mn5 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 81% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
What is 20Mn5 used for?
- Flanges
- Valve bodies
- Pressure vessel forgings
- Pipe fittings
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
- Readily welded — 78/100, better than 78% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
- Low strength — 320 MPa (46.4 ksi), worse than 81% of steel grades
20Mn5 properties
Typical room-temperature values for 20Mn5-+NT; bars are the position among steel grades.
Physical3
20Mn5 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
20Mn5 has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 81% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20Mn5 is rated for continuous service to 400°C (752 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
20Mn5 conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 20Mn5 takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
20Mn5's machinability is good (60/100, better than 83% of steel grades); weldability very good (78/100); formability good (60/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 20Mn5 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 20Mn5
Is 20Mn5 easy to machine?
Machines like a normalized 1021/1330-class steel — use carbide at 120–180 m/min with generous feed; the gummy ferrite-pearlite structure needs sharp tooling and chip breakers to avoid built-up edge.
Can 20Mn5 be welded?
Readily weldable by SMAW/GMAW/SAW with matching low-hydrogen consumables; CEV ≈ 0.45 so preheat 100–150 °C for sections above ~30 mm, and PWHT 580–620 °C is usual for pressure-code work.
Can 20Mn5 be formed, bent or molded?
Designed for hot forging at 1100–1250 °C with finishing above 850 °C, followed by normalizing; cold bending is limited by the ~25 % elongation and should use generous radii.
20Mn5 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 10222-2 heat analysis | 0.17 – 0.23 | 0.2 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 1 – 1.5 | 1.25 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| CrCr+Cu+Mo+Ni total ≤ 0.80 | ≤ 0.3 | 0.1 |
| Cu | ≤ 0.3 | 0.1 |
| Mo | ≤ 0.08 | 0.03 |
| Ni | ≤ 0.3 | 0.1 |
| Nb | ≤ 0.01 | 0.01 |
| V | ≤ 0.02 | 0.01 |
| AlAl total, grain refinement | ≥ 0.02 | 0.03 |
| Fe | balance |
What surface finishes work on 20Mn5?
No native corrosion protection — specify shot blast plus epoxy/zinc primer, hot-dip galvanizing or PTFE/rubber lining; phosphating suits bolted and threaded features.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 20Mn5 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.1133
- Similar grades
- A350 Gr. LF220MnMo
How much does 20Mn5 cost?
20Mn5 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
20Mn5 — frequently asked
What is 20Mn5 used for?
20Mn5 is typically used for flanges, valve bodies, pressure vessel forgings and pipe fittings. In short: pressure-purpose forging grade; A350 Gr. LF2 equivalent; weldable to pressure codes.
What is the yield strength of 20Mn5?
20Mn5 has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 81% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is 20Mn5 easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like a normalized 1021/1330-class steel — use carbide at 120–180 m/min with generous feed; the gummy ferrite-pearlite structure needs sharp tooling and chip breakers to avoid built-up edge.
Can 20Mn5 be welded?
Yes — weldability is rated very good (78/100). Readily weldable by SMAW/GMAW/SAW with matching low-hydrogen consumables; CEV ≈ 0.45 so preheat 100–150 °C for sections above ~30 mm, and PWHT 580–620 °C is usual for pressure-code work.
What surface finishes work on 20Mn5?
No native corrosion protection — specify shot blast plus epoxy/zinc primer, hot-dip galvanizing or PTFE/rubber lining; phosphating suits bolted and threaded features.
Can 20Mn5 be formed, bent or molded?
Designed for hot forging at 1100–1250 °C with finishing above 850 °C, followed by normalizing; cold bending is limited by the ~25 % elongation and should use generous radii.
What is the maximum service temperature of 20Mn5?
20Mn5 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 20Mn5 cost?
20Mn5 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- EN 10222-2 — Steel forgings for pressure purposes, ferritic and martensitic steels with specified elevated temperature properties — CEN (2017)
- ASTM A350/A350M — Carbon and Low-Alloy Steel Forgings for Piping Components with Notch Toughness Testing — ASTM International (2023)
- EN 10027 / Stahlschlüssel material 1.1133 designation data — Verlag Stahlschlüssel (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, machinability ratings for carbon steels — Industrial Press (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.