What Direct Materials Are Used to Make a Car

Automakers use a traceable bill of materials that becomes part of the finished vehicle, typically including ferrous and non‑ferrous metals (steel, cast iron, aluminum, copper, zinc), polymers and elastomers (plastics, foams, rubbers), glass, composites, electronic and magnetic materials (silicon, solders, PCB laminates, rare‑earth magnets), coatings and adhesives, fluids that remain in the vehicle, interior textiles and leathers, safety fabrics and pyrotechnics, and—depending on powertrain—battery materials (lithium‑based chemistries, graphite, separators, electrolytes) or emissions‑control precious metals. This article explains those direct materials, how they differ by vehicle type, and the trends shaping the mix in today’s cars.

What “Direct Materials” Means in Auto Manufacturing

In automotive cost accounting and production, direct materials are the physical inputs that can be economically traced to a specific vehicle and remain with it when it leaves the factory. They appear on the bill of materials (BOM) and include raw materials and purchased components that form the body, powertrain, interior, electrical systems, paint, and operational fluids. Indirect materials (such as welding gases or shop lubricants) support production but don’t become part of the finished car.

Core Material Categories Found in Most Cars

The following categories summarize the direct materials common to modern passenger vehicles across segments and brands. Items vary by design, performance targets, and regional regulations, but these are the foundational building blocks.

• Ferrous metals: Automotive sheet steels (mild, high-strength, advanced high-strength, boron-hardened, and stainless), cast irons and steels for structural or drivetrain parts.
• Non‑ferrous metals: Aluminum alloys (sheet, extrusions, castings—including large structural “gigacastings”), magnesium (select castings), copper (wiring, busbars, motors), zinc (galvanized coatings, die castings), and small amounts of tin and lead in certain components.
• Polymers and elastomers: Engineering plastics (PP, PE, ABS, PC, PA/nylon, POM, PMMA, PVC), thermoplastic elastomers, polyurethane foams (seating, NVH), rubbers (NR, SBR, EPDM, NBR) for tires, seals, hoses, and silicones for gaskets and thermal management.
• Glass and ceramics: Laminated safety glass for windshields, tempered glass for side/rear windows and panoramic roofs, and ceramic elements in sensors or catalytic substrates.
• Composites: Glass‑fiber reinforced plastics (GFRP), carbon‑fiber reinforced polymers (CFRP) and sheet‑molding compounds (SMC) for panels, roofs, and structural reinforcements.
• Electronics and magnetic materials: Silicon and silicon carbide power semiconductors, PCB laminates, solders (Sn‑Ag‑Cu families), connectors, wiring harnesses, and permanent magnets (NdFeB rare‑earth or ferrite) in motors and actuators.
• Coatings, adhesives, and sealants: Electrocoat (e‑coat), primers, basecoat and clearcoat systems; structural epoxies, polyurethanes, acrylic adhesives; seam sealers and sound-deadening mastics.
• Fluids that remain with the vehicle: Coolants, brake fluid, transmission or e‑axle oil, engine oil (ICE/HEV), refrigerants, washer fluid, and battery electrolytes.
• Interior and trim materials: Textiles (polyester, nylon, wool blends), carpets, headliners, natural fibers, leathers and synthetic leathers (PU, PVC), decorative foils and veneers.
• Safety systems materials: Airbag fabrics (typically woven nylon), inflator pyrotechnics and gas generants, seatbelt webbing (polyester), energy‑absorbing foams and metals.
• Exhaust and emissions control (for ICE/HEV): Stainless steels and ceramics for exhaust lines, and platinum‑group metals (platinum, palladium, rhodium) in catalytic converters.

Together, these categories form the architecture of the vehicle—from the “body‑in‑white” and chassis to the cabin, safety systems, electronics, and the fluids that enable operation and durability.

Direct Materials by Powertrain Type

Internal‑Combustion Engine (ICE) Vehicles

ICE cars rely on metals and exhaust aftertreatment materials alongside conventional plastics, glass, and rubber. The following list highlights direct materials specific to ICE models.

• Engine and transmission: Cast iron or aluminum blocks and heads; steel crankshafts and gears; aluminum housings; gaskets and seals (rubber, graphite, multi‑layer steel).
• Fuel and exhaust systems: Stainless steel fuel rails, injectors, pumps; stainless/ceramic exhaust components; catalytic converters with Pt/Pd/Rh; oxygen and NOx sensors.
• Operational fluids: Engine oil and transmission fluid that ship with the car; coolants and brake fluid; refrigerants for HVAC.
• 12‑volt battery: Lead‑acid chemistry (lead plates, sulfuric acid electrolyte, polypropylene case) unless replaced by lithium‑ion in newer designs.

These materials enable combustion, emissions control compliance, and drivability, and they remain with the vehicle throughout its service life.

Hybrid and Plug‑in Hybrid (HEV/PHEV)

Hybrids combine ICE components with electrified drive systems, adding battery and power electronics materials while keeping many conventional inputs.

• Battery packs: Typically lithium‑ion (NMC, NCA, or increasingly LFP) comprising cathode active material, graphite‑based anodes (with growing silicon blends), polyolefin separators, and LiPF6‑based electrolytes.
• Electric machines and power electronics: Copper windings, electrical steel laminations, permanent magnets (rare‑earth or ferrite), silicon or silicon‑carbide devices, thermal interface materials and TIM pads, and aluminum heat sinks.
• High‑voltage components: Shielded copper or aluminum HV cables, busbars, fuses, relays, and connectors designed for automotive standards.
• Conventional ICE and exhaust materials: As noted above, including catalysts with platinum‑group metals.

This dual material stack supports both combustion and electric propulsion, balancing efficiency, cost, and regulatory requirements.

Battery Electric Vehicles (BEVs)

BEVs eliminate the engine and exhaust system but add substantial battery, motor, and power electronics content alongside traditional body and interior materials.

• Traction battery: Cell chemistries such as LFP (lithium iron phosphate) or NMC (nickel‑manganese‑cobalt); anodes of graphite with optional silicon; separators (polyethylene/polypropylene); electrolytes (typically LiPF6 in carbonate solvents); pack enclosures of aluminum or steel with foams and fire‑retardant materials.
• Electric drive units: Copper windings or aluminum conductors, electrical steels, permanent magnets (NdFeB, sometimes with reduced heavy rare earth content), or induction motor rotors; gearsets and housings (steel and aluminum); e‑axle oils.
• Power electronics and charging: Silicon‑carbide MOSFET modules or IGBTs, busbars, capacitors, inductors, DC‑DC converters, onboard chargers, and robust thermal management materials.
• High‑voltage architecture: Shielded HV cables, connectors, fuses, and contactors designed to automotive standards.

These materials deliver high energy and power density, efficient conversion, and safety performance while reducing reliance on ICE‑specific inputs.

Where the Materials Go: Major Vehicle Systems

The list below maps material types to the systems and components most drivers recognize, clarifying how direct materials show up in the finished car.

• Body‑in‑white and closures: Steels (including advanced high‑strength grades) and aluminum for crash structures, doors, hoods, and liftgates; zinc coatings for corrosion protection.
• Chassis and suspension: Steels and aluminum for subframes, control arms, springs; elastomer bushings; brake discs (cast iron or composites) and calipers (aluminum or cast iron).
• Wheels and tires: Aluminum or steel wheels; tires made from natural and synthetic rubber, steel belts, textile cords, and silica‑based compounds.
• Glazing and lighting: Laminated and tempered glass; polycarbonate lenses; LEDs and optics; housings of ABS/PC blends with sealants and gaskets.
• Interior: Plastics (PP, ABS, PC/ABS), PU foams for seats, textiles and leathers, carpets, acoustic insulation, adhesives, and decorative trims.
• Electrical/electronic systems: Copper wiring harnesses, connectors, PCBs, sensors, ECUs, and in EVs, high‑voltage cabling and busbars.
• Surface finishes: E‑coat, primers, basecoat and clearcoat paint chemistry; underbody coatings and sealers for corrosion and noise control.
• Fluids and thermal systems: Coolants, oils, refrigerants, and heat‑exchanger materials (aluminum radiators, condensers).

These assemblies integrate dissimilar materials to meet safety, comfort, durability, and cost targets across the vehicle lifecycle.

Trends Shaping the Materials Mix (2024–2025)

Global automakers are adjusting material choices to meet efficiency targets, lower costs, and comply with evolving safety and sustainability rules. The items below highlight notable shifts.

• Lightweighting: Wider use of third‑generation advanced high‑strength steels, multi‑material body structures, and large aluminum castings to cut mass without compromising crashworthiness.
• Battery evolution: Broader adoption of LFP chemistries (lower cost, no nickel or cobalt) alongside NMC variants optimized for energy density; early pilots of sodium‑ion cells in entry segments.
• Magnet strategy: Reduction of heavy rare‑earth content in NdFeB magnets and selective use of ferrite or electrically excited motors to mitigate supply risk.
• Recycled and bio‑based content: More recycled aluminum and polymers, bio‑based plastics and natural fibers in interiors, and closed‑loop recycling for battery materials.
• Regulatory pressures: Tightening rules on end‑of‑life recyclability, extended producer responsibility, and restrictions on certain chemicals (with ongoing reviews of PFAS uses in automotive).

These trends influence both the bill of materials and supplier strategies, often trading off weight, cost, durability, and supply security.

What’s Not Considered Direct Material

Not every input used in the factory qualifies as a direct material. The following are typically indirect and excluded from the BOM.

• Production consumables: Welding gases, cutting fluids, mold‑release agents, and shop lubricants that do not remain with the vehicle.
• Energy and utilities: Electricity, natural gas, process water that isn’t retained in the product.
• Tooling and maintenance: Dies, molds, jigs, PPE, cleaning supplies, and spare parts for equipment.
• Packaging: Pallets, returnable totes, and protective materials not shipped to the end customer with the car.

These costs are necessary to build cars but are allocated as overhead rather than traceable direct material in financial reporting.

Summary

A car’s direct materials span metals (steel, aluminum, copper), polymers and elastomers, glass and composites, electronics and magnets, coatings and adhesives, operational fluids, interior fabrics, and—depending on the powertrain—either ICE exhaust aftertreatment with precious metals or EV battery chemistries and high‑voltage hardware. The exact mix varies by segment and design, but every vehicle’s BOM traces these inputs to the finished product, reflecting performance, safety, cost, and sustainability goals in today’s rapidly evolving automotive landscape.

What are examples of direct materials used in the production of a car?

Examples of direct materials
Automobile manufacturers need steel, rubber and plastic to build vehicles. These materials are direct materials because they’re reflected in the final product.

What are the raw materials used in automobiles?

The main materials used for making cars, parts and components, along with future trends, are steel, aluminum, magnesium, copper, plastics and carbon fibers. The prime reason for using steel in the body structure is its inherent capability to absorb impact energy in a crash situation.

What are direct materials used in production?

Direct materials used in production are the raw materials and parts that are directly traceable and physically incorporated into the final product. To calculate the cost of direct materials used, you add the cost of materials at the start of the period, the cost of materials purchased during the period, and then subtract the cost of materials remaining in ending inventory. Examples include wood for furniture, plastic for toys, or flour for a bakery. 
What they are: 

• Raw Materials: The fundamental ingredients or components that become part of the finished product.
• Directly Traceable: Their cost can be directly and easily identified and assigned to a specific product or batch.
• Quantifiable: They can be accurately measured and allocated to individual production runs or finished goods.

How they are used:

• Bill of Materials: The specific list of direct materials and their quantities required to produce one unit of a product. 
• Production Budget: A plan outlining the anticipated quantities and costs of materials needed to meet production targets. 
• Cost Allocation: Used to determine the direct cost of producing each item. 

Examples: 

• Furniture Manufacturing: Wood, nails, glue, and fabric.
• Electronics: Silicon and various components.
• Food Production: Flour, sugar, eggs, and milk for baked goods.
• Automobile Manufacturing: Steel and tires.

Key Considerations:

• Ancillary Costs: Opens in new tabThe total cost of direct materials includes not just the base price but also shipping, sales taxes, and storage fees incurred before production. 
• Variable Costs: Opens in new tabDirect material costs are typically considered variable costs, meaning they change in proportion to the volume of production. 
• Just-in-Time (JIT) Systems: Opens in new tabCan help reduce storage costs by only ordering and producing materials as they are needed for production. 

What are the materials used in making a car?

Steel, rubber, plastics, and aluminum are the four most common commodities found in cars. The auto industry relies heavily on petroleum products, not just for gasoline for autos with internal combustion engines (ICE), but for synthesizing plastics and other synthetic materials.