Steel Medium Carbon Steel · supply condition
Steel Medium Carbon Steel-CR
Properties of the CR condition, compared with the other Medium Carbon Steel tempers.
Pick for thin sheet/strip with tight thickness tolerance and a smooth bright surface; strength is up but bending ductility is limited.
What is Medium Carbon Steel-CR?
Medium Carbon Steel-CR is Medium Carbon Steel supplied in the CR condition — pick for thin sheet/strip with tight thickness tolerance and a smooth bright surface; strength is up but bending ductility is limited. Medium Carbon Steel-CR has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 71% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi). Medium Carbon Steel-CR 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; CR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- 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 82% of steel grades
Limitations
- Limited ductility — 10%, worse than 91% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 83% of steel grades
Medium Carbon Steel-CR properties
Typical room-temperature values for Medium Carbon Steel-CR — 10 properties are specific to this condition; the rest are grade-level values shared by every Medium Carbon Steel temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
Medium Carbon Steel-CR 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-CR has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 71% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
Medium Carbon Steel-CR 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-CR conducts electricity at 10 % IACS, better than 82% 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-CR 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-CR's machinability is good (58/100, better than 75% of steel grades); weldability fair (50/100); formability poor (28/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other Medium Carbon Steel tempers and conditions
Medium Carbon Steel is also supplied in 11 other conditions. The full side-by-side table is on the Medium Carbon Steel overview.
- HRDefaultDefault stock condition: cheapest form for shafts, plates and weldments that will be machined or later heat treated.330 MPa yield · 179 HB
- Q&T 38-42 HRCHighest through-hardness practical for plain medium carbon steel — for wear pins, cams and light dies; toughness and weldability drop sharply.1,080 MPa yield · 40 HRC
- Q&T 28-32 HRCCommon machine-shaft and gear-blank specification: high fatigue strength while still readily machinable.780 MPa yield · 30 HRC
- Q&TStandard 'through-hardened' engineering condition for shafts, gears and highly loaded pins; section size limits hardenability of plain carbon grades (water quench, <50 mm).660 MPa yield · 25 HRC
- Q&T 22-26 HRCPick when good machinability and impact toughness are wanted with a modest strength gain over normalized.610 MPa yield · 24 HRC
- CDBest choice for as-supplied dimensional accuracy, straightness and higher yield in shafting and turned parts; residual stress can cause distortion on unbalanced machining.580 MPa yield · 200 HB
- CRPick for thin sheet/strip with tight thickness tolerance and a smooth bright surface; strength is up but bending ductility is limited.550 MPa yield · 195 HB
- IHThe 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 MPa yield · 57 HRC
- NormalizedUse to homogenize forgings/weldments and get consistent strength and toughness through the section without quench distortion.350 MPa yield · 179 HB
- N+TChoose for large forgings and machined weldments where dimensional stability and moderate toughness matter more than peak strength.345 MPa yield · 170 HB
- AnnealedSoftest, most ductile and lowest-residual-stress condition — use before heavy cold forming or deep machining, or to relieve prior hardening.305 MPa yield · 156 HB
- SPHSpecified for cold heading, thread rolling and severe upsetting of medium carbon fasteners, where maximum cold ductility is needed.290 MPa yield · 143 HB
Working with Medium Carbon Steel-CR
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.
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.
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 | — |
Medium Carbon Steel-CR — frequently asked
What is Medium Carbon Steel-CR used for?
Medium Carbon Steel-CR is typically used for crankshafts, shafts and industrial bolts. In short: standard medium-carbon plate.
What is the yield strength of Medium Carbon Steel-CR?
Medium Carbon Steel-CR has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 650 MPa (94.3 ksi) — stronger than 71% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is Medium Carbon Steel-CR easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% 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-CR 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-CR?
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-CR 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-CR?
Medium Carbon Steel-CR 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.
Can FabDigit make parts in Medium Carbon Steel-CR?
Yes — Medium Carbon Steel-CR is available for CNC machining and sheet metal with instant online pricing. 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.