Steel C50
EN C50 · AISI/SAE 1050 · JIS S50C · GB 50
C50 is an unalloyed medium-to-higher carbon steel (~0.50 % C) to EN 10083 / 1.0540, also listed as C50E, 1050, S50C and Ck50, hardened by quenching and tempering with no deliberate alloy additions.
Reference datasheet — C50 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
C50 tempers and conditions
C50 is supplied in 11 conditions, soft to hard. N is the default FabDigit quotes; the values on this page are for it.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose when maximum cold-formability (upsetting, cold heading, deep machining) is needed before hardening. | 350 | 600 | 26 | 175 HB | 11 % IACS |
Solution annealed | Softest condition — pick for heavy machining, deep cold forming or before further heat treatment. | 365 | 636 | 24 | 187 HB | 50 W/m·K |
Hot rolled | Cheapest mill condition for stock removal parts that will be heat treated afterwards. | 415 | 725 | 15 | 197 HB | — |
NDefault Normalized | Standard stocked/uniform-structure condition: balanced strength and machinability, good base for later Q&T or induction hardening. | 425 | 750 | 20 | 217 HB | — |
Induction hardened | Use for shafts, gear teeth and rails needing a hard wear surface (55–62 HRC) with a tough unhardened core. | 500 | 800 | 15 | 58 HRC | 9.5 % IACS |
Cold drawn / cold finished bar | Pick for close tolerance, bright surface shafting where higher yield strength and short chips matter more than ductility. | 580 | 720 | 10 | 207 HB | — |
Quenched and tempered | Standard supply-condition Q&T for small sections needing guaranteed minimum yield with usable toughness. | 580 | 870 | 15 | 26 HRC | — |
Q&T 28–32 HRC (temper ~580–620 °C) | Tough general-purpose shaft/gear-blank condition; still readily machinable after heat treat. | 760 | 960 | 16 | 30 HRC | — |
Q&T 34–38 HRC (temper ~500–540 °C) | Higher-strength Q&T for moderately loaded gears, couplings and spindles where some toughness is still needed. | 950 | 1,150 | 12 | 36 HRC | — |
Q&T 40–45 HRC (temper ~400–450 °C) | Wear-oriented Q&T for small sections — high strength, limited ductility and low impact energy. | 1,150 | 1,350 | 9 | 43 HRC | — |
Hardened + low temper 150–200 °C | Maximum hardness/wear resistance for thin sections, springs and tools; brittle, avoid impact and stress raisers. | 1,600 | 1,900 | 3 | 56 HRC | — |
What is C50?
C50 is an unalloyed medium-to-higher carbon steel (~0.50 % C) to EN 10083 / 1.0540, also listed as C50E, 1050, S50C and Ck50, hardened by quenching and tempering with no deliberate alloy additions. It is chosen where more hardness and wear resistance are needed than C40 provides, and is available as hot-rolled and cold-drawn bar, forgings and heat-treated blanks — default properties are 425 MPa yield, 750 MPa tensile, 20 % elongation and 217 HB. Weldability is poor (CE ≈ 0.6–0.7) and formability is limited (score 32); there is no corrosion resistance. Use C40 for easier machining and welding, or C55 for higher hardness. C50 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). C50 has a yield strength of 425 MPa (61.6 ksi) and a tensile strength of 750 MPa (109 ksi) — weaker than 52% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
What is C50 used for?
- crankshafts
- gears
- axles
- high-strength bolts
- rail wheels
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High electrical conductivity — 10.5 % IACS, better than 89% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
Limitations
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
C50 properties
Typical room-temperature values for C50-N; bars are the position among steel grades.
Physical3
C50 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
C50 has a yield strength of 425 MPa (61.6 ksi) and a tensile strength of 750 MPa (109 ksi) — weaker than 52% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
C50 is rated for continuous service to 350°C (662 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
C50 conducts electricity at 10.5 % IACS, better than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of C50 takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
C50's machinability is fair (52/100, better than 52% of steel grades); weldability poor (32/100); formability poor (32/100).
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. C50 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C50
Is C50 easy to machine?
Machines best at 180–220 HB (annealed/normalized); above 32 HRC use coated carbide, rigid setups and reduced feeds — no free-machining sulfur unless the C50R variant is specified.
Can C50 be welded?
Poor weldability (CE ≈ 0.6–0.7): preheat 250–350 °C, low-hydrogen consumables, interpass control and post-weld stress relief/temper are required to avoid HAZ martensite cracking.
Can C50 be formed, bent or molded?
Cold forming only in annealed/spheroidized condition with generous bend radii (≥2–3 t); hot forge at 1100–850 °C then normalize; oil- or water-quench from 820–860 °C, temper 150–650 °C to the required hardness.
C50 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 steel 50: 0.47-0.55 | 0.47 – 0.55 | 0.5 |
| SiEN: Si ≤0.40; GB: 0.17–0.37 | 0.17 – 0.4 | 0.25 |
| MnEN C50: 0.60–0.90; GB 50: 0.50–0.80 | 0.5 – 0.9 | 0.7 |
| PC50E/C50R ≤0.030; GB ≤0.035 | ≤ 0.05 | 0.02 |
| SC50E ≤0.035; C50R 0.020–0.040 | ≤ 0.05 | 0.02 |
| Crresidual; GB ≤0.25 | ≤ 0.4 | 0.15 |
| Niresidual; GB ≤0.30 | ≤ 0.4 | 0.1 |
| Moresidual | ≤ 0.1 | 0.02 |
| Curesidual (GB ≤0.25) | ≤ 0.25 | 0.1 |
| Fe | balance |
What surface finishes work on C50?
Bare steel rusts quickly — protect by oiling, phosphating, black oxide, zinc or hard-chrome plating, or paint; grinds and polishes well after hardening.
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 C50 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does C50 cost?
C50 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.
C50 — frequently asked
What is C50 used for?
C50 is typically used for crankshafts, gears, axles, high-strength bolts and rail wheels. In short: higher hardness than C40; wear-resistant after quench and temper; weldable only with preheat.
What is the yield strength of C50?
C50 has a typical yield strength of 425 MPa (61.6 ksi) and a tensile strength of 750 MPa (109 ksi) — weaker than 52% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is C50 easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machines best at 180–220 HB (annealed/normalized); above 32 HRC use coated carbide, rigid setups and reduced feeds — no free-machining sulfur unless the C50R variant is specified.
Can C50 be welded?
Not readily — weldability is rated poor (32/100). Poor weldability (CE ≈ 0.6–0.7): preheat 250–350 °C, low-hydrogen consumables, interpass control and post-weld stress relief/temper are required to avoid HAZ martensite cracking.
What surface finishes work on C50?
Bare steel rusts quickly — protect by oiling, phosphating, black oxide, zinc or hard-chrome plating, or paint; grinds and polishes well after hardening.
Can C50 be formed, bent or molded?
Cold forming only in annealed/spheroidized condition with generous bend radii (≥2–3 t); hot forge at 1100–850 °C then normalize; oil- or water-quench from 820–860 °C, temper 150–650 °C to the required hardness.
What is the maximum service temperature of C50?
C50 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C50-N and C50 QT-Low?
N is the default condition — standard stocked/uniform-structure condition: balanced strength and machinability, good base for later Q&T or induction hardening. QT-Low: maximum hardness/wear resistance for thin sections, springs and tools; brittle, avoid impact and stress raisers. Yield strength is 425 MPa in N versus 1,600 MPa in QT-Low.
How much does C50 cost?
C50 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 steels (C50, C50E, C50R) — CEN (2006)
- JIS G 4051 Carbon steels for machine structural use (S50C) — JSA (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels (AISI 1050 data) — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating / Vol.16 Machining — ASM International (1991)
- SAE J403 / SAE J1397 estimated mechanical properties of carbon steel bars — SAE International (2020)
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.