Comprehensive Overview of Steel Used in Automobile Bodies

The car body is a crucial component of an automobile, forming the passenger space and contributing to the overall aesthetics and features of the vehicle. The choice of materials for car bodies must meet design, production, assembly, and maintenance requirements while satisfying criteria related to strength, rigidity, corrosion resistance, ductility, and weldability. Consequently, a diverse range of materials is employed in car body construction.

Classification of Materials for Car Bodies:

  1. Metal Materials: Heavy metals such as steel sheets, cast iron; light metals and their alloys including aluminum, magnesium, titanium; foam metals, etc.
  2. Non-Metal Materials: Engineering plastics, fibers, resins, glass, rubber, non-metal foams, non-metal composite materials, etc.
Steel Used in Automobile Bodies
Steel Used in Automobile Bodies

Usage Classification of Car Body Materials:

  1. Steel Sheets: Hot/cold-rolled steel sheets, surface-treated (coated) steel sheets, stainless steel sheets, high-strength steel sheets, etc.
  2. Light Metal Materials: Aluminum sheets, aluminum alloys, magnesium alloys, titanium alloys, etc.
  3. Composite Materials: Glass Fiber Reinforced Materials (GFRP), Carbon Fiber Reinforced Materials (CFRP), etc.
  4. Non-Metal Materials: Glass, plastics, rubber, leather, synthetic leather, chemical fibers, etc.
  5. Padding Materials: Leather, cardboard, cork, asbestos, synthetic leather, foam plastics, etc.
  6. Coating Materials: (Composition: Oil, Resin, Pigment, Solvent, Auxiliary Materials) Primer, topcoat, putty, auxiliary materials, etc.
  7. Interior Materials: Various fabrics, leather, soft materials, plastics, etc.
  8. Adhesives: Sealants, adhesives, etc.

Steel Sheets for Car Bodies: Steel sheet properties include plasticity, elasticity, work hardening, etc.

  1. Hot-Rolled Mild Steel Sheets: Low carbon content, low hardness, and tensile strength. Used for mudguards, floors, trunk hinges, bumpers, etc.
  2. Cold-Rolled Mild Steel Sheets: Better processing performance and aesthetic surfaces. Used for outer panels, shells of parts, roof panels, trunk lids, engine hoods, inner and outer panels of doors, bumpers, mudguards, etc.
  3. High-Strength Steel Sheets: Extremely high tensile strength, ideal for outer panels, fenders, etc.
  4. Surface-Treated Steel: Galvanized steel, zinc powder-painted steel, etc., for doors, roof liners, underbody, etc.

Types of Automotive Steel (3 categories):

  1. Outer Panel Steel: Used for manufacturing outer panels of front, rear, left, and right doors, engine hood, trunk lid, etc. Requires good formability, corrosion resistance, dent resistance, and weldability.
  2. Inner Panel Steel (Inner plates for four-door structures): Used for more complex inner panel components. Requires higher formability and deep-drawing performance, often employing IF steel or IF-phosphorus-added steel.
  3. Advanced High-Strength Steel (BIW Components): Used for car body structural components. Requires high strength, good plasticity, and potential for thickness reduction.

Specific Steel Types (9 examples):

  1. Ultra-Deep Drawing IF Cold-Rolled Steel Sheets: For excellent formability, corrosion resistance, and weldability. Mainly includes Ti-IF steel (St16) and (Ti + Nb) – IF steel (BIF3, equivalent to St17).
  2. Cold-Rolled High-Strength Steel Sheets: Phosphorus-strengthened, offering strong formability and dent resistance.
  3. Bake-Hardening (BH) Steel Sheets: Heat-treated after stamping for increased yield strength.
  4. Transformation-Induced Plasticity (TRIP) Steel: Complex structure for high strength and good plasticity.
  5. Dual-Phase Steel Sheets: Ideal combination of high strength and good plasticity.
  6. Surface-Treated Steel Sheets (Combined with High-Strength Steel): Galvanized, alloyed hot-dip galvanized (GA), Zn-Ni alloy-plated, double-layer Zn-Fe alloy-plated, thin organic composite steel.
  7. Vibration Damping Composite Steel Sheets: Sandwich structure with a polymer damping layer for reduced vibration and noise, enhancing comfort.
  8. Hot-Rolled Acid-Pickled Steel Sheets: Low-cost with high strength, used for chassis and structural components, replacing some cold-rolled steel sheets.
  9. Other Advanced High-Strength Steels: Developed for specific applications, providing a balance between strength and ductility.

This comprehensive guide provides insights into the diverse range of materials used in constructing car bodies, emphasizing their specific properties and applications within the automotive industry. Contact us for more.

Albert Turner

Albert Turner is an experienced steel content writer with over 5 years of experience creating content related to the steel industry. Albert has solid professional knowledge of steel and can explain all aspects of steel production, processing, application and other aspects in a simple and easy-to-understand manner. He is familiar with various steel standards and specifications and can tailor content to the needs of his target audience.