Steel Medium Carbon Steel
Medium carbon steel is a plain-carbon (or lightly manganese-alloyed) steel with roughly 0.30–0.60 % C, the classic 'general engineering' steel family typified by AISI/SAE 1040–1050 and GB/T 699 grade 45.
Values for the HR condition
Medium Carbon Steel tempers and conditions
Medium Carbon Steel 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 |
|---|---|---|---|---|---|---|
Spheroidize annealed | Specified for cold heading, thread rolling and severe upsetting of medium carbon fasteners, where maximum cold ductility is needed. | 290 | 520 | 26 | 143 HB | 10.5 % IACS |
full anneal, slow furnace cool | Softest, most ductile and lowest-residual-stress condition — use before heavy cold forming or deep machining, or to relieve prior hardening. | 305 | 560 | 22 | 156 HB | — |
HRDefault Hot rolled | Default stock condition: cheapest form for shafts, plates and weldments that will be machined or later heat treated. | 330 | 585 | 16 | 179 HB | — |
Normalized and tempered | Choose for large forgings and machined weldments where dimensional stability and moderate toughness matter more than peak strength. | 345 | 600 | 20 | 10 HRC | 10 % IACS |
austenitize + air cool (uniform fine pearlite) | Use to homogenize forgings/weldments and get consistent strength and toughness through the section without quench distortion. | 350 | 630 | 18 | 179 HB | — |
Induction hardened | The classic use of medium carbon steel: hard wear-resistant case (55–60 HRC) on a tough core for shaft journals, gear teeth and rails. | 420 | 700 | 14 | 57 HRC | 8.5 % IACS |
Cold rolled | Pick for thin sheet/strip with tight thickness tolerance and a smooth bright surface; strength is up but bending ductility is limited. | 550 | 650 | 10 | 195 HB | — |
Cold drawn | Best choice for as-supplied dimensional accuracy, straightness and higher yield in shafting and turned parts; residual stress can cause distortion on unbalanced machining. | 580 | 690 | 12 | 200 HB | — |
Quenched and high-temperature tempered | Pick when good machinability and impact toughness are wanted with a modest strength gain over normalized. | 610 | 780 | 18 | 24 HRC | 9.5 % IACS |
Quenched and tempered | Standard 'through-hardened' engineering condition for shafts, gears and highly loaded pins; section size limits hardenability of plain carbon grades (water quench, <50 mm). | 660 | 830 | 16 | 25 HRC | 45 W/m·K |
Quenched and tempered | Common machine-shaft and gear-blank specification: high fatigue strength while still readily machinable. | 780 | 960 | 15 | 30 HRC | — |
Quenched and low-temperature tempered | Highest through-hardness practical for plain medium carbon steel — for wear pins, cams and light dies; toughness and weldability drop sharply. | 1,080 | 1,250 | 11 | 40 HRC | — |
What is Medium Carbon Steel?
Medium carbon steel is a plain-carbon (or lightly manganese-alloyed) steel with roughly 0.30–0.60 % C, the classic 'general engineering' steel family typified by AISI/SAE 1040–1050 and GB/T 699 grade 45. It is chosen for the best balance of strength, toughness, machinability and cost, and it responds well to normalizing, quench-and-temper and induction/flame surface hardening for shafts, gears, axles, bolts and dies. Limits are poor corrosion resistance (needs paint, oxide, phosphate or plating), reduced weldability above ~0.35 % C (preheat/post-weld heat treatment), low hardenability in thick sections and marked notch sensitivity at low temperature. Medium Carbon Steel 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). Medium Carbon Steel has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 78% of steel grades. Elongation at break is 16% and the elastic modulus is 205 GPa (29.7 Msi).
What is Medium Carbon Steel used for?
- Crankshafts
- Shafts
- Industrial bolts
Advantages
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
Limitations
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
- Low strength — 330 MPa (47.9 ksi), worse than 78% of steel grades
Medium Carbon Steel properties
Typical room-temperature values for Medium Carbon Steel-HR; bars are the position among steel grades.
Physical3
Medium Carbon Steel 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
Medium Carbon Steel has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 78% of steel grades. Elongation at break is 16% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
Medium Carbon Steel is rated for continuous service to 400°C (752 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
Medium Carbon Steel conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of Medium Carbon Steel takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
Medium Carbon Steel's machinability is good (55/100, better than 62% of steel grades); weldability fair (50/100); 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. Medium Carbon Steel is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Medium Carbon Steel
Is Medium Carbon Steel easy to machine?
Machines well at ~180–230 HB with carbide tooling (typ. 120–200 m/min turning); above 300 HB use coated carbide/CBN, rigid setups and expect tool-life loss — normalize or spheroidize before heavy cuts.
Can Medium Carbon Steel be welded?
Weldable but crack-sensitive: preheat 150–260 °C for >0.35 %C or thick sections, use low-hydrogen electrodes (E7018/ER70S-6), control interpass temperature and post-weld stress relieve/normalize.
Can Medium Carbon Steel be formed, bent or molded?
Hot forging 1100–1200 °C is ideal; cold bending/heading needs annealed or spheroidized material and generous bend radii (≥2t), since cold ductility is much lower than mild steel.
Manufacturability
The process limits FabDigit applies to Medium Carbon Steel. Every Medium Carbon Steel 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.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 | Better40 / 100 |
|---|---|
| Weldability | Better50 / 100 |
| Bendable | Yes |
Medium Carbon Steel 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 |
|---|---|---|
| Cdefining range of the medium carbon class (e.g. 1045/GB 45 = 0.42–0.50) | 0.3 – 0.6 | 0.45 |
| Mn0.60–0.90 in 1045; up to 1.65 in the 15xx resulfurized/high-Mn series | 0.3 – 1 | 0.7 |
| Sikilled steel; not specified for rimmed grades | 0.15 – 0.35 | 0.25 |
| P | ≤ 0.04 | 0.02 |
| S0.08–0.13 in free-machining 1145/1146 variants | ≤ 0.05 | 0.03 |
| Crresidual only in plain carbon grades | ≤ 0.25 | 0.1 |
| Niresidual | ≤ 0.25 | 0.1 |
| Curesidual | ≤ 0.25 | 0.15 |
| Fe | balance |
What surface finishes work on Medium Carbon Steel?
No anodizing — protect by paint/primer, black oxide, zinc phosphate, hot-dip galvanize or Zn/Cr/Ni plating (bake after plating to avoid hydrogen embrittlement in hardened parts); polishes to a good bright finish but rusts quickly unbaked/unoiled.
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 Medium Carbon Steel in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- medium-carbon steel
How much does Medium Carbon Steel cost?
Medium Carbon Steel 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.
Medium Carbon Steel — frequently asked
What is Medium Carbon Steel used for?
Medium Carbon Steel is typically used for crankshafts, shafts and industrial bolts. In short: standard medium-carbon plate.
What is the yield strength of Medium Carbon Steel?
Medium Carbon Steel has a typical yield strength of 330 MPa (47.9 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 78% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is Medium Carbon Steel easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines well at ~180–230 HB with carbide tooling (typ. 120–200 m/min turning); above 300 HB use coated carbide/CBN, rigid setups and expect tool-life loss — normalize or spheroidize before heavy cuts.
Can Medium Carbon Steel be welded?
With care — weldability is rated fair (50/100). Weldable but crack-sensitive: preheat 150–260 °C for >0.35 %C or thick sections, use low-hydrogen electrodes (E7018/ER70S-6), control interpass temperature and post-weld stress relieve/normalize.
What surface finishes work on Medium Carbon Steel?
No anodizing — protect by paint/primer, black oxide, zinc phosphate, hot-dip galvanize or Zn/Cr/Ni plating (bake after plating to avoid hydrogen embrittlement in hardened parts); polishes to a good bright finish but rusts quickly unbaked/unoiled.
Can Medium Carbon Steel be formed, bent or molded?
Hot forging 1100–1200 °C is ideal; cold bending/heading needs annealed or spheroidized material and generous bend radii (≥2t), since cold ductility is much lower than mild steel.
What is the maximum service temperature of Medium Carbon Steel?
Medium Carbon Steel 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 Medium Carbon Steel-HR and Medium Carbon Steel-CD?
HR is the default condition — default stock condition: cheapest form for shafts, plates and weldments that will be machined or later heat treated. CD: best choice for as-supplied dimensional accuracy, straightness and higher yield in shafting and turned parts; residual stress can cause distortion on unbalanced machining. Yield strength is 330 MPa in HR versus 580 MPa in CD.
How much does Medium Carbon Steel cost?
Medium Carbon Steel 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 Medium Carbon Steel?
Yes — Medium Carbon Steel 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
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- SAE J403 / J1397 — Chemical compositions and estimated mechanical properties of SAE carbon steels — SAE International (2019)
- GB/T 699 — (grades 35, 40, 45, 50) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (induction and through hardening of carbon steels) — ASM International (1991)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- CES / Ashby material property data — carbon steel (medium carbon) — Granta Design (2021)
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.