Steel C25
EN C25
C25 is an unalloyed medium-carbon engineering steel (1.0406, AISI 1025, JIS S25C) supplied as-rolled, annealed, normalized, cold-drawn, quenched-and-tempered or induction-hardened.
Reference datasheet — C25 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 +N condition
C25 tempers and conditions
C25 is supplied in 6 conditions, soft to hard. +N is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose for maximum ductility before heavy cold forming, deep drawing or cold heading. | 220 | 400 | 32 | 111 HB | — |
Hot rolled | Cheapest mill condition for weldments and non-critical structural parts; scale and looser tolerances. | 225 | 400 | 25 | 116 HB | — |
+NDefault Normalized | Standard stocked condition — uniform fine grain, balanced strength/toughness for shafts, pins and forgings. | 265 | 440 | 30 | 126 HB | — |
Induction hardened | Selected when only local wear resistance is needed on shaft journals; maximum attainable case hardness is limited by the 0.25 % C content. | 265 | 440 | 24 | 42 HRC | 9.5 % IACS |
Cold drawn | Pick for close tolerance, bright surface and higher yield strength on automatic-lathe parts; lower ductility and residual stress. | 390 | 470 | 15 | 137 HB | — |
Quenched and tempered | Use for small-section pins and bolts needing higher yield; hardenability is low so benefit disappears above ~25 mm diameter. | 410 | 610 | 22 | 12 HRC | — |
What is C25?
C25 is an unalloyed medium-carbon engineering steel (1.0406, AISI 1025, JIS S25C) supplied as-rolled, annealed, normalized, cold-drawn, quenched-and-tempered or induction-hardened. It is chosen for shafts, pins and forged parts that need more strength and hardenability than C22 while staying easy to weld; the default condition gives 265 MPa yield, 440 MPa tensile, 30 % elongation and 126 HB (71 HRB). Maximum service temperature is about 400 °C and the steel has no corrosion resistance, so plating or paint is required. For deeper hardening in larger sections, step up to C45. C25 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). C25 has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 92% of steel grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi).
What is C25 used for?
- shafts
- pins
- forged machine parts
- axles
Advantages
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
- Readily welded — 88/100, better than 87% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
Limitations
- Low strength — 265 MPa (38.4 ksi), worse than 92% of steel grades
C25 properties
Typical room-temperature values for C25-+N; bars are the position among steel grades.
Physical3
C25 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
C25 has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 92% of steel grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
C25 is rated for continuous service to 400°C (752 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
C25 conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of C25 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 28%.
Manufacturability8
C25's machinability is good (62/100, better than 89% of steel grades); weldability excellent (88/100); formability good (65/100).
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. C25 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C25
Is C25 easy to machine?
Free-machining-free grade: cold-drawn condition cuts best; normalized bar can be gummy, so use positive-rake carbide, 150–250 m/min and generous coolant to avoid built-up edge.
Can C25 be welded?
Readily welded by SMAW/GMAW/GTAW with E70xx/ER70S-x consumables; CEV ≈ 0.40 so preheat 100–150 °C only for sections over ~25 mm or high restraint.
Can C25 be formed, bent or molded?
Good cold bending and heading in +A/+N condition (bend radius ≈ 1–1.5 t); hot forging 1100–1250 °C followed by normalizing restores grain size.
C25 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 C25 / 1.0406 | 0.22 – 0.29 | 0.25 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.4 – 0.7 | 0.55 |
| P | ≤ 0.05 | 0.02 |
| SC25E ≤0.035 S, C25R 0.020–0.040 S | ≤ 0.05 | 0.03 |
| Crresidual | ≤ 0.4 | 0.1 |
| Niresidual | ≤ 0.4 | 0.1 |
| Moresidual; Cr+Mo+Ni ≤ 0.63 | ≤ 0.1 | 0.02 |
| Fe | balance |
What surface finishes work on C25?
No anodizing — protect with zinc/zinc-nickel plating, phosphate + oil, black oxide, e-coat or paint; can be case-hardened or induction hardened for wear surfaces.
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 C25 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does C25 cost?
C25 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.
C25 — frequently asked
What is C25 used for?
C25 is typically used for shafts, pins, forged machine parts and axles. In short: stronger than C22; weldable shaft steel; induction-hardenable carbon grade.
What is the yield strength of C25?
C25 has a typical yield strength of 265 MPa (38.4 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 92% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is C25 easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Free-machining-free grade: cold-drawn condition cuts best; normalized bar can be gummy, so use positive-rake carbide, 150–250 m/min and generous coolant to avoid built-up edge.
Can C25 be welded?
Yes — weldability is rated excellent (88/100). Readily welded by SMAW/GMAW/GTAW with E70xx/ER70S-x consumables; CEV ≈ 0.40 so preheat 100–150 °C only for sections over ~25 mm or high restraint.
What surface finishes work on C25?
No anodizing — protect with zinc/zinc-nickel plating, phosphate + oil, black oxide, e-coat or paint; can be case-hardened or induction hardened for wear surfaces.
Can C25 be formed, bent or molded?
Good cold bending and heading in +A/+N condition (bend radius ≈ 1–1.5 t); hot forging 1100–1250 °C followed by normalizing restores grain size.
What is the maximum service temperature of C25?
C25 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.
What is the difference between C25 +N and C25-IH?
+N is the default condition — standard stocked condition — uniform fine grain, balanced strength/toughness for shafts, pins and forgings. IH: selected when only local wear resistance is needed on shaft journals; maximum attainable case hardness is limited by the 0.25 % C content. Yield strength is 265 MPa in +N versus 265 MPa in IH.
How much does C25 cost?
C25 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 10083-2 Steels for quenching and tempering — Non-alloy quality steels — CEN (2006)
- JIS G 4051 Carbon steels for machine structural use (S25C) — JISC (2016)
- ASTM A29/A29M — Steel bars, carbon and alloy, hot-wrought (1025) — ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- Stahlschlüssel / Key to Steel 1.0406 — Verlag Stahlschlüssel (2019)
- Mysteel / SMM — Mysteel (2025)
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.