CK-45

Grade Introduction

Carbon Steel CK 45 is suitable for mean strained parts of higher dimensions (heavy forged parts) and complexed forms in vehicle manufacturing and machine engineering (e.g. ship shafts, transmission parts, wheel hubs). Lowest application temp. -25 °C, favorable creep behavior up to 480 °C.

Grade Application:

Suitable for manufacturing various strong cutting tools with wear-resistant, resistant to impact. Advanced punching die, screw die, the toughness and complicated shape of the punch, etc. Roll cutting tool industry: scraper, serrated knife, iron knives, drill bits, etc.

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Chemical Composition

The following table shows the chemical composition of CK45 steel:

Element C Si Mn P S
Content(%) 0.42-0.5 0.4 0.5-0.8 0.04 0.03


Mechanical Properties

Elastic modulus 217 GPa at – 100 °C
Elongation 4 -8 % at 20 °C
Poisson’s ratio 0.29 [-]  at 20 °C
Shear modulus 75 – 80 GPa at 20 °C
Tensile strength 580 – 770 MPa at 20 °C
Yield strength 330 – 640 MPa at 20 °C

Hardness:

Hardness, Rockwell C (Water quenched on 820-870°C, 5 minutes): 201~269HB

Heat treatment:

Heat Treatment of AISI 1045 (CK45) followed by furnace cooling at 50ºF (28ºC) per hour, to 1200ºF (650ºC) soaking and air cooling. Hardening of this grade is carried out from an austenitizing temperature of 1475-1550ºF (800-845ºC) and oil or water quenching.

Hardening:

Hardening of this grade is carried out from an austenitizing temperature of 1475-1550ºF (800-845ºC) and oil or water quenching.

Flame and induction hardening may be carried out by heating quickly to the desired case depth and quenching in water or oil. This should be followed by a tempering treatment at 300-400ºF (150-200ºC) to reduce stresses in the case without affecting its hardness. A surface hardness of Rc 58 may be obtained by this treatment.

Tempering:

Tempering temperature / ℃ : 552

After tempering hardness HRC or higher: 201-269HB.

Physical Properties:

Quantity Value Unit
Thermal expansion 10 – 10 e-6/K
Thermal conductivity 25 – 25 W/m.K
Specific heat 460 – 460 J/kg.K
Melting temperature 1450 – 1510 °C
Density 7700 – 7700 kg/m3
Resistivity 0.55 – 0.55 Ohm.mm2/m

Thermal Properties

  • Coefficient of thermal expansion α        1.08E-5 1/K at -100 °C
  • Thermal conductivity λ         41.7 W/(m·K) at 20 °C
  • Thermal diffusivity αdiff          11.6 mm²/s at 20 °C


Forging Properties:

At first, Pre-Heating to 552℃，Then heat to forged temperature. Next, Soak at 820-870 °C , ensure heat thorough. Then start forged, the forged temperature no low than 560℃. After forging, cool slowly.

Normalizing

Normalizing: 840-870°C

Annealing:

Full annealing of small C1045 forgings is carried out from 1450-1600ºF (790-870ºC) followed by furnace cooling at 50ºF (28ºC) per hour, to 1200ºF (650ºC) soaking and air cooling.

Density

Density       7.8 g/cm³ at 20 °C

Machinability:

Machinability is good, rated at 80% that of the AISI 1112 alloy used as a 100% machining rated steel.