Steel C45Pb · supply condition · default condition
Steel C45Pb-CD
Properties of the CD condition, compared with the other C45Pb tempers.
Standard stock condition: close tolerance, bright surface, high strength — the usual feed for CNC/auto-lathe turned parts.
What is C45Pb-CD?
C45Pb-CD is C45Pb supplied in the CD condition — standard stock condition: close tolerance, bright surface, high strength — the usual feed for CNC/auto-lathe turned parts. C45Pb-CD has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 70% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi). C45Pb-CD 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).
Advantages
- Easy to machine — 70/100, better than 96% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High electrical conductivity — 10.7 % IACS, better than 91% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
Limitations
- Limited ductility — 9%, worse than 93% of steel grades
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 90% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 77% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
C45Pb-CD properties
Typical room-temperature values for C45Pb-CD — 11 properties are specific to this condition; the rest are grade-level values shared by every C45Pb temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
C45Pb-CD 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
C45Pb-CD has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 70% of steel grades. Elongation at break is 9% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
C45Pb-CD is rated for continuous service to 300°C (572 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
C45Pb-CD conducts electricity at 10.7 % IACS, better than 91% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of C45Pb-CD takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
C45Pb-CD's machinability is very good (70/100, better than 96% of steel grades); weldability poor (25/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other C45Pb tempers and conditions
C45Pb is also supplied in 7 other conditions. The full side-by-side table is on the C45Pb overview.
- CDDefaultStandard stock condition: close tolerance, bright surface, high strength — the usual feed for CNC/auto-lathe turned parts.540 MPa yield · 205 HB
- QT 28-32 HRCOrdered when a drawing calls out a hardness band for wear and thread strength on small-diameter bar.750 MPa yield · 30 HRC
- QTUse for loaded shafts, pins and threaded parts needing higher yield with usable toughness.550 MPa yield · 21 HRC
- IHSelect for journals and guide surfaces needing a hard, wear-resistant case over a tough core.550 MPa yield · 55 HRC
- SHPick for slender or asymmetrically machined parts where cold-drawing stresses would cause distortion.500 MPa yield · 200 HB
- NUniform fine-pearlitic structure; balanced strength and toughness for general machined parts.380 MPa yield · 195 HB
- HRCheapest mill condition for parts that will be fully machined or later heat treated.340 MPa yield · 185 HB
- AChoose when maximum machinability and low hardness are wanted before final hardening.320 MPa yield · 180 HB
Working with C45Pb-CD
Is C45Pb easy to machine?
Excellent for a 0.45 %C steel — lead gives short chips, lower cutting force and good surface finish; run high speeds with carbide, use dry or oil mist and collect swarf as lead-bearing waste.
Can C45Pb be welded?
Poor: 0.45 %C plus lead promotes hot cracking and porosity; avoid welding, or preheat 200–300 °C, use low-hydrogen consumables and post-weld temper, and ventilate for lead fume.
Can C45Pb be formed, bent or molded?
Limited cold formability (bend radii ≥3t, elongation <12 % in CD); hot form at 850–1150 °C but avoid holding near 1100 °C+ where lead causes hot shortness.
What surface finishes work on C45Pb?
No anodizing; protect with oil, phosphate, black oxide, zinc or nickel plating — bake after plating to limit hydrogen embrittlement in hardened conditions; polishes to a fair finish.
C45Pb 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 |
|---|---|---|
| C | 0.42 – 0.5 | 0.45 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.5 – 0.8 | 0.65 |
| P≤0.035 for quality-steel grades | ≤ 0.05 | — |
| Soften 0.020–0.040 to aid chip breaking | ≤ 0.05 | 0.03 |
| Pbfree-cutting addition | 0.15 – 0.35 | 0.25 |
| CrCr+Mo+Ni ≤ 0.63 total | ≤ 0.4 | — |
| Ni | ≤ 0.4 | — |
| Mo | ≤ 0.1 | — |
| Fe | balance | — |
C45Pb-CD — frequently asked
What is C45Pb-CD used for?
C45Pb-CD is typically used for shafts, bolts and spindles. In short: leaded medium-carbon machining bar.
What is the yield strength of C45Pb-CD?
C45Pb-CD has a typical yield strength of 540 MPa (78.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 70% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is C45Pb-CD easy to machine?
Yes — machinability is rated very good (70/100, better than 96% of steel grades). Excellent for a 0.45 %C steel — lead gives short chips, lower cutting force and good surface finish; run high speeds with carbide, use dry or oil mist and collect swarf as lead-bearing waste.
Can C45Pb-CD be welded?
Not readily — weldability is rated poor (25/100). Poor: 0.45 %C plus lead promotes hot cracking and porosity; avoid welding, or preheat 200–300 °C, use low-hydrogen consumables and post-weld temper, and ventilate for lead fume.
What surface finishes work on C45Pb-CD?
No anodizing; protect with oil, phosphate, black oxide, zinc or nickel plating — bake after plating to limit hydrogen embrittlement in hardened conditions; polishes to a fair finish.
Can C45Pb-CD be formed, bent or molded?
Limited cold formability (bend radii ≥3t, elongation <12 % in CD); hot form at 850–1150 °C but avoid holding near 1100 °C+ where lead causes hot shortness.
What is the maximum service temperature of C45Pb-CD?
C45Pb-CD is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C45Pb-CD and C45Pb-A?
CD is the default condition — standard stock condition: close tolerance, bright surface, high strength — the usual feed for CNC/auto-lathe turned parts. A: choose when maximum machinability and low hardness are wanted before final hardening. Yield strength is 540 MPa in CD versus 320 MPa in A.
Can FabDigit make parts in C45Pb-CD?
Yes — C45Pb-CD is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- EN 10083-2 Steels for quenching and tempering — non-alloy quality steels — CEN (2006)
- EN 10277-3 Bright steel products — free-cutting steels — CEN (2018)
- EN 10027-2 / Werkstoff-Nummer 1.1201 designation system — CEN (2015)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels — ASM International (1990)
- Bright bar / free-cutting steel datasheets (C45, C45Pb) — European bright-bar producers (2022)
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.