Steel 5140-SA (Spheroidize Annealed)
Heat-treated state
AISI/SAE 5140 · UNS G51400 · EN 1.7035, 41Cr4 · JIS SCr440 · GB 40Cr
Pick for cold heading, cold extrusion or deep upsetting of bolts and fasteners.
Values for the SA condition
Other 5140 tempers and conditions
5140 is listed in 12 conditions; see the grade overview at 5140.
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 | — |
SAThis page 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-SA?
5140-SA is 5140 heat treated to SA — pick for cold heading, cold extrusion or deep upsetting of bolts and fasteners. 5140-SA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 86% of steel grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi). 5140-SA 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). HR is the default condition FabDigit quotes; SA is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Forms and bends easily — 70/100, better than 86% of steel grades
Limitations
- Low strength — 300 MPa (43.5 ksi), worse than 86% of steel grades
5140-SA properties
Typical room-temperature values for 5140-SA; 22 are specific to this condition. Other listed values are 5140 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
5140-SA 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-SA has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 86% of steel grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
5140-SA is rated for continuous service to 400°C (752 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
5140-SA conducts electricity at 8.1 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 5140-SA 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-SA's machinability is good (60/100, better than 83% of steel grades); weldability fair (42/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 5140-SA
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).
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.
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 | — |
5140-SA — frequently asked
What is 5140-SA used for?
5140-SA is typically used for shafts, gears and axles. In short: workhorse chromium spring bar.
What is the yield strength of 5140-SA?
5140-SA has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 86% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is 5140-SA easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% 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-SA be welded?
With care — weldability is rated fair (42/100). 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-SA?
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-SA 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-SA?
5140-SA 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.
Can FabDigit make parts in 5140-SA?
Yes — 5140-SA 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.