CK45 Forgings
CK45 is C45 with tightened residual limits — lower sulphur and phosphorus than standard commercial grades. That cleanliness gives more consistent heat treatment response and better surface finish after machining.
- Carbon
- 0.42 – 0.50%
- Sulphur
- 0.035% max
- Phosphorus
- 0.035% max
- Tensile (Q&T)
- 700 – 850 MPa
- Hardness (Q&T)
- 220 – 280 BHN
- Equivalent
- 1.1191, C45E, SAE 1045
CK45 Forgings at a glance
Quotable facts from Avadh Techno Forge, Gundasara, Gondal, Rajkot.
- Carbon: 0.42 – 0.50%
- Sulphur: 0.035% max
- Phosphorus: 0.035% max
- Tensile (Q&T): 700 – 850 MPa
- Hardness (Q&T): 220 – 280 BHN
- Equivalent: 1.1191, C45E, SAE 1045
Controlled Residuals Matter
Sulphur and phosphorus segregate to grain boundaries and reduce toughness and fatigue strength. CK45's tighter limits produce more predictable properties, which shows up as tighter hardness spread across a production batch.
- Lower sulphur and phosphorus
- Consistent heat treatment response
- Better machined surface finish
- Tighter hardness distribution
Where the Premium Pays
Hydraulic cylinder rods, precision shafts and any part where an inconsistent hardness result would cause rework. On general brackets and pins, standard C45 or EN8 remains the economical choice.
Treatment and Properties
Normalised at 180–230 BHN for machining, or quenched and tempered to 220–280 BHN. Induction hardening lifts wear surfaces to 55 HRC.
CK45 Composition: Where the Difference Lies
CK45 is C45 with tightened residual limits — notably lower sulphur and phosphorus than standard commercial grades. Sulphur and phosphorus segregate towards grain boundaries and reduce toughness and fatigue strength, so restricting them produces steel that responds to heat treatment more consistently and finishes better after machining. The chemistry difference looks small on paper and shows up as a tighter hardness spread across a production batch.
| Property | Typical value |
|---|---|
| Carbon | 0.42 – 0.50% |
| Manganese | 0.50 – 0.80% |
| Sulphur | 0.035% maximum |
| Phosphorus | 0.035% maximum |
| Tensile strength, quenched and tempered | 700 – 850 MPa |
| Hardness, quenched and tempered | ≈ 220 – 280 HB |
| Induction hardened surface | Up to ≈ 55 HRC |
| Material number | 1.1191 (C45E) |
Where the CK45 Premium Is Worth Paying
On hydraulic cylinder rods, precision shafts and any component where an inconsistent hardness result would mean rework, the tighter residual limits repay themselves. On general brackets, pins and lightly loaded parts they do not, and standard C45 or EN8 is the economical answer. The grade is also a good choice where a part will be chrome plated or ground, because cleaner steel gives a better finished surface. See forged piston rods.
People also ask
Is CK45 worth paying more for than C45?
On precision shafts and hydraulic rods yes, because tighter residual limits give more consistent heat treatment response. On general brackets and pins, standard grades are more economical.
What does the K in CK45 signify?
Restricted sulphur and phosphorus content compared with standard C45, giving cleaner steel with more predictable properties.
Topics covered on this page
- CK45 forging manufacturer India
- C45 quality steel forging
- CK45 forged components supplier
- quality carbon steel forging Rajkot
Based on work carried out at our own forging plant at Gundasara, Gondal, Rajkot — operating since 2008.
Questions Answered
What is the difference between C45 and CK45?
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CK45 has tighter sulphur and phosphorus limits, giving more consistent heat treatment response and better surface quality.
Is CK45 worth the extra cost?
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On precision shafts and hydraulic rods, yes. On general brackets and pins, standard grades are more economical.
Can CK45 be induction hardened?
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Yes, to around 55 HRC on wear surfaces with a tough core retained.
What is CK45 used for?
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Hydraulic cylinder rods, precision shafts, spindles and machined components needing predictable properties.