Steel 5140
AISI/SAE 5140 · UNS G51400 · EN 1.7035, 41Cr4 · JIS SCr440 · GB 40Cr
5140 (G51400, 41Cr4, 1.7035, 40Cr, SCr440) is a medium-carbon chromium alloy steel from the SAE-AISI 51xx family, used quenched and tempered for a balance of strength, toughness and machinability.
Values for the HR condition
5140 tempers and conditions
5140 is supplied in 12 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full anneal ~815 °C, furnace cooled | Softest, most machinable condition; use for heavy stock removal before hardening. | 293 | 572 | 28.6 | 167 HB | — |
Spheroidize Annealed | Pick for cold heading, cold extrusion or deep upsetting of bolts and fasteners. | 300 | 550 | 30 | 160 HB | 8.1 % IACS |
HRDefault Hot rolled | Cheapest stock condition for parts that will be heat treated after rough machining. | 440 | 700 | 18 | 200 HB | — |
~870 °C, air cooled | Uniform fine-grain structure for forgings before machining or final Q&T. | 472 | 793 | 22.7 | 20 HRC | — |
Cold rolled | Cold-rolled strip/sheet for stamped or formed blanks that are hardened afterwards. | 620 | 760 | 10 | 18 HRC | 7.8 % IACS |
Cold drawn | Choose for close-tolerance, bright-finish bar used as-supplied for lightly loaded shafts and pins. | 660 | 760 | 13 | 19 HRC | 45 W/m·K |
tempered ~540–565 °C | Specified hardness band for machinable shafts, couplings and moderately loaded gears. | 840 | 980 | 18 | 30 HRC | 7.5 % IACS |
Quenched and tempered | Standard general-purpose condition for shafts and gears — good strength/toughness balance (~30 HRC). | 860 | 1,000 | 17.5 | 32 HRC | — |
Induction hardened | Select for shaft journals, splines and gear teeth needing a hard wear surface with a tough core. | 860 | 1,000 | 15 | 55 HRC | 7.5 % IACS |
tempered ~480–510 °C | Higher-strength band for heavily loaded shafts and gear blanks still requiring machining. | 1,080 | 1,180 | 14 | 36 HRC | — |
tempered ~400–430 °C | Use where wear and high yield strength dominate and toughness demands are moderate. | 1,260 | 1,380 | 12 | 42 HRC | — |
low temper ~205–260 °C | Maximum-hardness condition for small wear parts; brittle, avoid stress raisers and impact. | 1,560 | 1,720 | 9 | 50 HRC | — |
What is 5140?
5140 (G51400, 41Cr4, 1.7035, 40Cr, SCr440) is a medium-carbon chromium alloy steel from the SAE-AISI 51xx family, used quenched and tempered for a balance of strength, toughness and machinability. Annealed and hot-rolled bar runs 440 MPa yield, 700 MPa tensile, 18 % elongation and about 200 HB, while the Q&T tempers on file cover 28-32 HRC through 48-52 HRC plus induction hardening. It has no corrosion resistance and needs preheat with post-weld tempering if welded; for thicker sections or higher tempering temperatures 4140/42CrMo4 is the usual step up. 5140 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). 5140 has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 50% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
What is 5140 used for?
- Shafts
- Gears
- Axles
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
5140 properties
Typical room-temperature values for 5140-HR; bars are the position among steel grades.
Physical3
5140 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
5140 has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 50% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
5140 is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
5140 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 5140 takes about 26 MJ of energy and emits 1.9 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
5140's machinability is good (58/100, better than 75% of steel grades); weldability fair (35/100); formability fair (40/100).
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. 5140 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 5140
Is 5140 easy to machine?
Machines well at 180–230 HB (≈65 % of 1212); above 35 HRC use coated carbide, rigid setups and reduced feeds, and prefer rough-machining before final temper.
Can 5140 be welded?
Weldable with care only — preheat 250–350 °C, low-hydrogen consumables, and temper/stress-relieve immediately after welding to avoid martensitic cracking.
Can 5140 be formed, bent or molded?
Hot forge 1100–1200 °C then normalize; cold forming limited to the spheroidize-annealed condition (cold heading of bolts).
Manufacturability
The process limits FabDigit applies to 5140. Every 5140 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better58 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 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 | Fair40 / 100 |
|---|---|
| Weldability | Better35 / 100 |
5140 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 |
|---|---|---|
| CGB 40Cr: 0.37–0.44 | 0.38 – 0.43 | 0.4 |
| SiGB 40Cr: 0.17–0.37 | 0.15 – 0.35 | 0.25 |
| MnGB 40Cr: 0.50–0.80 | 0.7 – 0.9 | 0.8 |
| CrGB 40Cr / 41Cr4: 0.80–1.10 | 0.7 – 0.9 | 0.8 |
| P | ≤ 0.04 | |
| Smax; 0.015–0.035 for resulfurized machining grades | ≤ 0.04 | |
| Fe | balance |
What surface finishes work on 5140?
No corrosion resistance — protect by black oxide, phosphate + oil, zinc or chrome plating (bake to relieve hydrogen above 40 HRC); polishes to a fine finish when clean and hardened.
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 5140 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 5140 cost?
5140 is a standard-cost steel ($$), cheaper than about 71% 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.
5140 — frequently asked
What is 5140 used for?
5140 is typically used for shafts, gears and axles. In short: workhorse chromium spring bar.
What is the yield strength of 5140?
5140 has a typical yield strength of 440 MPa (63.8 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 50% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is 5140 easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines well at 180–230 HB (≈65 % of 1212); above 35 HRC use coated carbide, rigid setups and reduced feeds, and prefer rough-machining before final temper.
Can 5140 be welded?
With care — weldability is rated fair (35/100). Weldable with care only — preheat 250–350 °C, low-hydrogen consumables, and temper/stress-relieve immediately after welding to avoid martensitic cracking.
What surface finishes work on 5140?
No corrosion resistance — protect by black oxide, phosphate + oil, zinc or chrome plating (bake to relieve hydrogen above 40 HRC); polishes to a fine finish when clean and hardened.
Can 5140 be formed, bent or molded?
Hot forge 1100–1200 °C then normalize; cold forming limited to the spheroidize-annealed condition (cold heading of bolts).
What is the maximum service temperature of 5140?
5140 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 5140-HR and 5140-IH?
HR is the default condition — cheapest stock condition for parts that will be heat treated after rough machining. IH: select for shaft journals, splines and gear teeth needing a hard wear surface with a tough core. Yield strength is 440 MPa in HR versus 860 MPa in IH.
How much does 5140 cost?
5140 is a standard-cost steel ($$), cheaper than about 71% 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 5140?
Yes — 5140 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 J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- GB/T 3077 — Alloy Structure Steels (40Cr) — SAC (2015)
- EN 10083-3 — Quenched and tempered steels, 41Cr4 (1.7035) — CEN (2006)
- JIS G 4053 — Low-alloyed structural steels (SCr440) — JSA (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- Mysteel / SMM 40Cr (2026)
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.