Introduction

CK45 Bright Bar is a medium carbon steel grade widely used for manufacturing high-strength parts that require superior tensile strength and good wear resistance. This grade of steel is often chosen for applications where high strength and toughness are required. CK45 steel offers a good balance between hardness and toughness, making it an ideal choice for manufacturing precision components.

CK45 is widely used in various industries, including automotive, mechanical engineering, and construction, for producing parts such as shafts, gears, and axles. It is available in the form of bright bars, which are produced with a smooth and polished surface finish that reduces the need for further machining.

Properties of CK45 Bright Bar:

The key properties of CK45 Bright Bar include:

  • Strength: CK45 exhibits excellent tensile strength, making it ideal for applications involving mechanical stress.
  • Hardness: The medium carbon content gives CK45 a higher hardness compared to mild steel, enhancing its wear resistance.
  • Ductility: Although CK45 has high strength, it also maintains good ductility, which is important for applications requiring some flexibility.
  • Machinability: The material offers good machinability, which is crucial for manufacturing complex parts using conventional machining techniques.
  • Surface Finish: As a bright bar, CK45 has a smooth, polished finish, which reduces the need for post-machining and improves the surface quality of the final product.

Uses/Applications:

CK45 Bright Bar is used in a wide range of industrial and mechanical applications, including:

  • Automotive Industry: Manufacturing components like shafts, gears, crankshafts, camshafts, and axles.
  • Mechanical Engineering: Suitable for parts like rods, spindles, and pins that require high strength and wear resistance.
  • General Fabrication: For structural and load-bearing components, as well as precision engineering components.
  • Tool Making: Often used in the production of tools and dies due to its excellent hardness and strength.
  • Heavy Machinery: Ideal for high-stress components such as connecting rods, fasteners, and other mechanical parts subjected to dynamic loads.

Chemical Composition:

CK45 Bright Bar is a medium-carbon steel with the following typical chemical composition:

Element Composition Range
Carbon (C) 0.42% – 0.50%
Silicon (Si) 0.10% – 0.40%
Manganese (Mn) 0.60% – 0.90%
Phosphorus (P) ≤ 0.035%
Sulfur (S) ≤ 0.035%
Iron (Fe) Balance

This composition gives CK45 its characteristic strength and toughness, allowing it to perform well in applications that require high mechanical properties.

Mechanical Properties:

CK45 Bright Bar offers superior mechanical properties, which can be further enhanced with heat treatment. The key mechanical properties of CK45 include:

Condition Yield Strength (MPa) Tensile Strength (MPa) Elongation (%)
As-rolled ≥ 350 580-720 ≥ 16
Tempered ≥ 400 700-850 ≥ 12

These properties ensure CK45’s suitability for high-load applications, such as automotive and mechanical engineering components.

Physical Properties:

CK45 Bright Bar also exhibits the following physical properties:

  • Density: 7.85 g/cm³ (typical for medium-carbon steels).
  • Modulus of Elasticity: 200 GPa, providing sufficient resistance to deformation under stress.
  • Melting Point: 1425–1475°C, which allows it to be used in higher temperature environments and during heat treatment processes.

These properties contribute to the material’s overall performance in both mechanical and thermal applications.

Heat Treatment:

CK45 Bright Bar can undergo various heat treatments to improve its mechanical properties, including:

  • Annealing: Heat to 680–700°C, then allow the material to cool slowly. This process softens the steel and improves its machinability.
  • Normalizing: Heat to 850–880°C and allow the material to air-cool. Normalizing refines the grain structure, enhancing toughness and strength.
  • Quenching and Tempering: Quenching in water or oil at 870–900°C, followed by tempering at 550–650°C, increases the hardness and tensile strength of the material. This process is typically used to achieve higher hardness for parts that will experience heavy wear.

Forging:

  • CK45 Bright Bar can be forged effectively within a temperature range of 1050°C to 1150°C.
  • Maintaining this temperature range is crucial to avoid overheating, which could lead to undesirable mechanical properties.
  • Proper temperature control ensures that the material retains its strength and toughness after forging.

Weldability

CK45 Bright Bar is weldable using various welding techniques, including:

  • MIG (Metal Inert Gas) Welding
  • TIG (Tungsten Inert Gas) Welding
  • Stick Welding (SMAW)

Dimensional Tolerances:

CK45 Bright Bar is available in a wide range of sizes with tight dimensional tolerances, which makes it ideal for precision applications. Typical dimensions for CK45 Bright Bar include:

  • Round Bars: Diameters from 10 mm to 100 mm.
  • Square Bars: Sizes range from 10 mm to 75 mm.
  • Hexagonal Bars: Available in sizes from 15 mm to 40 mm.
  • Flat Bars: Width and thickness range from 20 mm to 100 mm.

These precise tolerances ensure that the material can be used directly in manufacturing without the need for additional shaping or finishing.

For sections above 15 mm in thickness, preheating to 100–150°C is recommended to reduce the risk of cracking. Post-weld heat treatment may also be required to relieve stresses and improve the mechanical properties of the welded joint.

Machinability:

CK45 Bright Bar offers good machinability, allowing it to be easily turned, milled, drilled, and tapped. It can be processed with conventional cutting tools and equipment. When machining CK45, it is recommended to use cutting fluids or lubricants to minimize tool wear and improve the surface finish of the material. For better machinability, it is often subjected to an annealing process to soften the steel.

Corrosion Resistance:

While CK45 offers moderate resistance to corrosion, it is not suitable for use in highly corrosive environments. Exposure to moisture, chemicals, or salt can lead to rusting. To enhance its corrosion resistance, protective coatings such as galvanizing, painting, or plating are often applied, particularly in applications where the material will be exposed to harsh environmental conditions.

Available Form:

CK45 Bright Bar is available in various forms to meet different industrial requirements:

  • Round Bars: Used in shaft and spindle applications, commonly used for rotating components.
  • Square Bars: Used in manufacturing and machining processes requiring a more angular profile.
  • Hexagonal Bars: Ideal for applications requiring a specific shape for locking mechanisms or keyways.
  • Flat Bars: Typically used for structural components, frame building, and fabrication.
  • Custom Profiles: Available for specific applications or customer requirements.

Conclusion:

CK45 Bright Bar is a medium-carbon steel offering an excellent balance of strength, hardness, and machinability. It is widely used in automotive, mechanical engineering, and industrial manufacturing for producing parts that need to withstand heavy loads, wear, and fatigue. The material’s good weldability, machinability, and availability in various forms make it an essential choice for many industrial applications.

With the right heat treatment, CK45 can be tailored to meet the specific needs of high-performance components in various industries. However, its susceptibility to corrosion means that protective measures should be taken in corrosive environments.

Related Products : CK45, EN8, Bright Bar, SAE 1010, IS 2062, SAE 1018,  Maps