Steel 1040
AISI/SAE 1040 · UNS G10400 · EN 1.0511, C40 · JIS S40C · GB 40
1040 is a plain medium-carbon (≈0.40 % C) engineering steel supplied hot rolled, cold drawn or quenched and tempered; it is the classic low-cost choice for shafts, axles, gears, bolts, studs, couplings and machine parts needing 550–800 MPa strength and good machinability.
Values for the HR condition
1040 tempers and conditions
1040 is supplied in 10 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Quenched and high-tempered 650 °C | Softest Q&T level — maximum ductility and impact toughness with a tempered structure, used for heavily cold-worked or welded assemblies. | 345 | 552 | 33 | 170 HB | 10 % IACS |
full anneal ~790 °C, slow cool | Softest condition — choose for maximum ductility before cold forming, deep machining or further heat treatment. | 353 | 519 | 30 | 149 HB | — |
~900 °C, air cool | Uniform fine pearlitic structure with the best toughness/strength balance of the untempered conditions; standard pre-machining condition for forgings. | 374 | 590 | 28 | 170 HB | — |
HRDefault Hot rolled | Cheapest general-purpose stock for shafting, plate and structural machine parts where tolerance and surface finish are not critical. | 415 | 620 | 25 | 201 HB | — |
Quenched and tempered | Pick this quenched (845 °C, water) and ~540 °C tempered condition for shafts and fasteners: 434 MPa yield with retained toughness and easy machining at roughly 185–200 HB. | 434 | 634 | 29 | 12 HRC | — |
Induction hardened | Choose when journals, splines or cam faces need 50+ HRC wear resistance while the core stays tough. | 450 | 700 | 18 | 55 HRC | 9 % IACS |
Cold rolled | Cold-rolled strip/sheet for stamped and formed parts needing better finish and thickness tolerance than hot rolled. | 490 | 640 | 15 | 190 HB | 10 % IACS |
Quenched and tempered 425 °C | Choose quenching with a 425 °C temper when about 758 MPa tensile is needed but the part must still be turned and drilled easily at 20–24 HRC. | 517 | 758 | 23 | 22 HRC | — |
Cold drawn | Pick for close-tolerance bright bar, higher yield strength and improved chip control on automatic lathes. | 565 | 655 | 12 | 190 HB | — |
Quenched and low-tempered | Highest strength through-hardened condition for small sections (pins, keys, links) where toughness demands are moderate. | 593 | 779 | 19 | 27 HRC | — |
What is 1040?
1040 is a plain medium-carbon (≈0.40 % C) engineering steel supplied hot rolled, cold drawn or quenched and tempered; it is the classic low-cost choice for shafts, axles, gears, bolts, studs, couplings and machine parts needing 550–800 MPa strength and good machinability. It through-hardens only in modest sections (water quench, low hardenability) and is often induction- or flame-hardened for wear surfaces. Limits: essentially no corrosion resistance (must be painted, plated or oiled), reduced weldability above ~0.30 % C so preheat/post-weld tempering is needed, and notch toughness falls off sharply below about −20 °C. 1040 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). 1040 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 56% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
What is 1040 used for?
- Crankshafts
- Couplings
- Shafts
Advantages
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
Limitations
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
1040 properties
Typical room-temperature values for 1040-HR; bars are the position among steel grades.
Physical3
1040 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
1040 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 56% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1040 is rated for continuous service to 425°C (797 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
1040 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 1040 takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
1040's machinability is good (55/100, better than 62% of steel grades); weldability fair (45/100); formability fair (45/100).
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. 1040 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1040
Is 1040 easy to machine?
Machines readily at ~60 % of 1212; best chip control in cold-drawn or 180–220 HB Q&T condition, use rigid setups and coolant since 0.40 % C is gummier than free-cutting grades.
Can 1040 be welded?
Weldable with low-hydrogen SMAW/GMAW but preheat 150–260 °C, control interpass temperature and stress-relieve/temper after welding to avoid martensitic HAZ cracking.
Can 1040 be formed, bent or molded?
Cold form only in annealed or normalized condition with generous bend radii; hot forge 1100–1230 °C and normalize afterwards.
Manufacturability
The process limits FabDigit applies to 1040. Every 1040 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better55 / 100 |
|---|---|
| ISO material group | P.1 |
| Cutting speed (rough / finish) | 220 / 260 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better45 / 100 |
|---|---|
| Weldability | Better45 / 100 |
1040 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 |
|---|---|---|
| CSAE J403 / ASTM A29 heat analysis | 0.37 – 0.44 | 0.4 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.05 | 0.03 |
| Sinot specified in SAE J403 for bar; typical mill practice / required by JIS S40C and EN 1.0511 | 0.15 – 0.35 | 0.25 |
| Fe | balance |
What surface finishes work on 1040?
No inherent corrosion resistance — specify paint, zinc/chrome plating, phosphate+oil, black oxide or nitrocarburizing; polishes to a good bright finish but rusts quickly if unprotected.
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).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 1040 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 1040 cost?
1040 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.
1040 — frequently asked
What is 1040 used for?
1040 is typically used for crankshafts, couplings and shafts. In short: excellent wear resistance.
What is the yield strength of 1040?
1040 has a typical yield strength of 415 MPa (60.2 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 56% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 1040 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines readily at ~60 % of 1212; best chip control in cold-drawn or 180–220 HB Q&T condition, use rigid setups and coolant since 0.40 % C is gummier than free-cutting grades.
Can 1040 be welded?
With care — weldability is rated fair (45/100). Weldable with low-hydrogen SMAW/GMAW but preheat 150–260 °C, control interpass temperature and stress-relieve/temper after welding to avoid martensitic HAZ cracking.
What surface finishes work on 1040?
No inherent corrosion resistance — specify paint, zinc/chrome plating, phosphate+oil, black oxide or nitrocarburizing; polishes to a good bright finish but rusts quickly if unprotected.
Can 1040 be formed, bent or molded?
Cold form only in annealed or normalized condition with generous bend radii; hot forge 1100–1230 °C and normalize afterwards.
What is the maximum service temperature of 1040?
1040 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.
What is the difference between 1040-HR and 1040-CD?
HR is the default condition — cheapest general-purpose stock for shafting, plate and structural machine parts where tolerance and surface finish are not critical. CD: pick for close-tolerance bright bar, higher yield strength and improved chip control on automatic lathes. Yield strength is 415 MPa in HR versus 565 MPa in CD.
How much does 1040 cost?
1040 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.
Can FabDigit make parts in 1040?
Yes — 1040 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- ASTM A108 — Steel Bar, Carbon and Alloy, Cold-Finished — ASTM (2018)
- JIS G 4051 — Carbon steels for machine structural use (S40C) — JSA (2016)
- EN 10083-2 / EN 10277 — Steels for quenching and tempering (C40, 1.0511) — CEN (2006)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Metals Handbook / Bringas 'Handbook of Comparative World Steel Standards' — ASTM (2004)
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.