New automotive materials are constantly being introduced to improve vehicle’s crash safety, noise and vibration, fuel economy and overall cost. While cars of the past consisted of entirely steel-based products, manufacturers are now transitioning towards aluminum, magnesium, and composite materials that deliver enhanced performance. To accommodate for these new materials, new manufacturing techniques are also being adopted.
There is some uncertainty in the automotive industry that could change how quickly these advanced vehicle technologies become market standard. New materials must be safe, cost-efficient, and commercialized if they are likely to be used for more vehicle components. To achieve these production standards, the manufacturing process itself must improve first.
What are the Most Commonly Used Automotive Materials?
Center for Automotive Resear’s 2017 Technology Roadmaps report identifies current materials and manufacturing technologies used in 42 vehicles, covering four vehicle segments (cars, CUV, SUV, light trucks) from model year 2015/2016. The 42 models sampled represent approximately 50% of light-duty vehicle sales in the U.S.
Source: CAR Research-Automotive Technology Roadmaps (2017)
Today, and into the foreseeable future, the most commonly used automotive materials include:
Mild Steel: Mild steels are easy to form, which makes them a top choice for automotive parts manufacturers using cold stamping and other dated manufacturing processes.
High Strength Steel (HSS): High strength steels use traditional steels and remove carbon during the baking cycle. This means softer steels can be formed, then baked into harder metals.
High Strength Low Alloy (HSLA): HLSAs are carbon manganese steels strengthened with the addition of a micro alloying element such as titanium, vanadium, or niobium.
Advanced High Strength Steel (AHSS): Advanced high strength steels are composites made of multiple metals, then heated and cooled throughout the manufacturing process to meet a part’s specifications.
Ultra High Strength Steel (UHSS): UHSS follow similar properties as AHSS.
Boron/Martensite: Martensite is the hardest and strongest form of steel, but it is also the least formable. These are usually combined with softer steels to form composites.
Aluminum 5000/6000 (AL 5000/6000): 5000-series aluminum is alloyed with magnesium. 6000-series aluminum contains both silicon and magnesium which forms magnesium silicide and makes the aluminum alloy heat-treatable.
Magnesium: Magnesium is an attractive material for automotive use because of its light weight. When alloyed, magnesium has the highest strength-to-weight ratio of all structural metals.
Carbon Fiber Reinforced Plastic (CFRP): CFRPs are extremely strong, light plastics which contain carbon fibers to increase strength. They are expensive to produce but will have a growing demand in the future automotive industry as costs are reduced.
The composition of vehicles are quickly changing and becoming incredibly diverse. In the 10-year period of 2010 to 2020, mild steel use will be cut in half and will be replaced with higher-strength steels, aluminum, and composites. This trend will continue to unfold well into the future as automotive materials become more advanced and cost-competitive with traditional steels.
Innovative Methods of Automotive Parts Manufacturing
Cold formed steel is still the industry standard for manufacturing automotive parts, but, high-strength materials are the future.
Some of the innovative manufacturing processes what will redefine automotive parts include:
Hot Formed Steel: Increasing the heat of steel improves ductility and helps form complex shapes without cracking.
Warm Formed Aluminum: Aluminum require less heat but follow a similar logic to heating steel.
High Pressure Thin Walled Aluminum Die Casting: Aluminum’s high melting and solidifying temperature points mean that thin aluminum molds need to be filled quickly before temperatures cool. This creates the need for high heat, high pressure manufacturing processes.
Resin Transfer Molding: Resins are pumped at high pressure into molds where they meet a pre-inserted fibre preform. This transforms light preform materials into high-strength automotive parts.
3D Printing: 3D printing offers manufacturers the opportunity to develop prototypes and full-scale parts that are significantly more complex than possible when forming or molding.
Source: CAR Research-Automotive Technology Roadmaps (2017)
How will Automotive Manufacturing Materials and Processes Evolve?
The automotive manufacturing timelines or ‘roadmaps’ provided in CAR’s report are a calculated look at the future based on current materials and process trends.
Each innovative manufacturing technology and material has factors that could impact predicted timelines.
Fuel Economy: Lighter materials will lead to lighter vehicles that require less fuel for propulsion.
Vehicle Emission Reduction: Legislative requirements may force automotive manufacturers to improve fuel economy as a means to lower greenhouse gas (GHG) emissions.
Autonomous Vehicles: Self-driving vehicles have significantly more components than driver-required vehicles. This extra weight and space needs to be offset through the lightening of the other parts.
Electric Power-Train: The switch to less heavy electric power-trains requires other materials to be lighter to compensate.
Added Content: Drivers expect improved vehicle features each model year and components need to become lighter over time or else fuel economy will suffer.
Mixed Material Joining: Differences in melting points between materials means that traditional welding techniques must be innovated.
Corrosion: Exposure to moisture can break down new materials over time, causing failure of vehicle systems.
Thermal Expansion: As parts enter paint ovens, parts made of some materials may expand or be coated differently than other materials.
Cycle Time: Parts made of innovative materials need to be manufactured at a similar speed as traditional techniques to ensure a similar throughput.
Cost: New materials such as carbon fiber can cost more than traditional materials.
Supply Chain: Manufacturers across the world must be able to source materials and maintain the equipment to process it.
End-of-life Recycling: Automotive materials should be recyclable upon the retirement of a vehicle. Some advanced materials do not meet recycling requirements.
Repair: Repair costs are higher with more complex materials, which increases cost of ownership including ongoing maintenance fees.
Talent Gap: Engineers and manufacturing plant workers need to be trained on new complex materials and processes.
For the full report on "Technology Roadmaps: Intelligent Mobility Technology, Materials and Manufacturing Processes and Light Duty Vehicle Propulsion" by the Center for Automotive Research, click here.
Shepherd, Jeff. (2018). "Next-Generation Automotive Manufacturing Materials and Processes". Retrieved from https://www.mentorworks.ca/blog/market-trends/automotive-manufacturing-materials-processes/.