Increasing Safety Requirements Demand Stronger Steel

With an increasing awareness about car safety – governments and regulatory agencies have been passing stricter safety regulations for autos. At the same time, consumers began demanding better protections, and car makers began building safer vehicles. While there are many factors to consider in building a safer car – airbags, seatbelts, glass type – the crashworthiness, or structural integrity, of the car’s body frame is one of the most critical.

In 1975 the average vehicle was manufactured with 55.9% mild steel and just 3.6% medium and high strength steels. By 2007, the percentage of medium and high strength steels used in an average car had increased by more than 230%. In the seventies, steel companies simply did not have the technology to make the steel that they can produce today because while it was strong, it was brittle and difficult to work with. Today, innovations in steel technology have given car makers the ability to use a variety of advanced high-strength steels (AHSS) that exceed 1,000MPa – meaning it can withstand more than 100 kilograms-force per square millimeter – because they are both strong and formable.

To demonstrate how far we come in terms of building stronger, safer vehicles, watch this crash test performed by the IIHS for their 50th anniversary with a 1959 Chevrolet Bel Air and a 2009 Chevrolet Malibu.

POSCO GIGA STEEL, the Industry’s New Standard for Strength and Formability

With a tensile strength of more than 1,000MPa, POSCO GIGA STEEL falls in the strongest categories of steel available to auto manufacturers today. In addition to providing the strength needed to meet safety regulations, POSCO GIGA STEEL is also ideal because of its formability and processability.

While recent years have seen ultra strength steels come on to the market with tensile ratings above 1,000MPa, these have often been rigid and brittle, making them difficult to process and mold into workable parts. POSCO GIGA STEEL bridges that gap by offering an automotive steel solution with high ductility and high tensile strength. This unique technology makes POSCO GIGA STEEL a unique fit for automakers seeking materials that can be processed into complex parts while also offering the highest levels of strength and safety for consumers.

Because of the combination of both strength and formability, SsangYong Motor unveiled their new G4 Rexton SUV with a body frame that contains 63% POSCO GIGA STEEL – the highest ratio ever achieved in a body frame design. Manufacturers like SsangYong Motor can use such high ratios of AHSS because of the technological advancements that have improved its formability in line with its improvements in strength.

The body frame of SsangYong Motor’s new G4 Rexton is manufactured with 63% POSCO GIGA STEEL.

Testing the Strength of POSCO GIGA STEEL and Aluminum

As lightweighting has become a priority for car makers seeking to build more fuel efficient cars, many have been looking toward alternative materials to step in as a substitute for steel. However, while offering certain benefits in weight, these alternative materials offer tradeoffs in strength and formability. On the other hand, POSCO GIGA STEEL offers an ideal solution in terms of strength, weight, and formability for auto manufacturers that must adhere to safety and environmental regulations along with consumer demand.

To compare the strength and impact energy absorption of POSCO GIGA STEEL (CR1180TRIP) and aluminum (Al5083), researchers at the KAIST National Center for Standard Reference Data performed an experiment in which a projectile was fired at three equidistantly spaced pieces of POSCO GIGA STEEL and aluminum.

Traveling at 185 meters per second, researcher Park Myung-joon noted that “the projectile ripped through all three pieces of aluminum while not even breaking one sheet of the POSCO GIGA STEEL.” Saying, “This experiment helped demonstrate how POSCO GIGA STEEL is more than three times stronger than aluminum making it ideal for automotive applications.”

Watch the video below to see how the experiment was designed, set up, and carried out.

POSCO GIGA STEEL is seeing increasing demand with car makers as they realize the dual benefits of strength and formability. At the Seoul Motor Show last month, Renault Samsung Motors and Chevrolet both unveiled new vehicles that were made using POSCO GIGA STEEL instead of aluminum – boosting the car body’s strength and safety for passengers.

Due to POSCO GIGA STEEL’s increased strength and high formability, the new Renault Samsung QM6 was able to maintain excellent safety standards with easy integration into its production process.

POSCO GIGA STEEL is unique because it combines both strength and formability. With strength more than three times stronger than aluminum and with formability properties that allow it to be made into complex auto parts – POSCO GIGA STEEL is the most ideal solution for car makers today.

Throughout April & May, The Steel Wire will explore the uses and benefits of POSCO GIGA STEEL and what POSCO is doing to lead the industry with new automotive steel solutions.

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Several factors are contributing to the growing interest in electric vehicles. Stricter CO2 emission standards are changing the way cars are being made, and consumers are becoming more environmentally conscious at the same time. To produce more fuel efficient vehicles, car makers are looking to advanced materials in lightweighting that can help make vehicles more eco-friendly while being safe and affordable.

The Push to Reduce Carbon Emissions

In the US, the transportation sector produces nearly 30 percent of all global warming emissions, and more than half of those emissions come from passenger vehicles. Between 1990 and 2004, the average fuel economy of new vehicles actually decreased, but since 2005 those numbers have begun to improve, resulting in less greenhouse emissions (see chart below).

Greenhouse gas emissions from the transportation sector remain high but have gone down in recent years. Increased efforts by the auto industry to produce more fuel-efficient cars is helping this trend. (Source: EPA Inventory of US Greenhouse Gas Emissions and Sinks: 1990-2014)

As air pollution gets worse and global temperatures continue to rise, governments, consumers, and car manufacturers have all seen the urgency in creating more fuel-efficient vehicles. However, in order to build electric vehicles, hybrid cars, and even more fuel efficient combustion engine autos, new materials and production methods must be used. Specifically, cars need to be lighter.

Reducing Weight, Reducing CO2 Emissions

The heavier a car is, the more fuel is required to move it. A study from MIT found that for each 100-kg reduction in a car’s body weight, fuel consumption could decrease by about 0.3 L/100 km for cars and about 0.4 L/100 km for light trucks. This not only translates into fewer CO2 emissions but also into cost savings for consumers. The following table provides estimated fuel cost savings for a range of weight reductions. Today’s cars and light trucks weigh between 1,000 to 3,800 kg.

Manufacturers have been testing new materials to use in their cars in order to make the weight reductions necessary for a viable EV. Utilization of alternative materials like aluminum, magnesium, and carbon fiber components are increasing due to their lightweight properties. However, additional financial and environmental costs remain high.

In the past, in order to make steel lighter, sacrifices had to be made in strength and ductility. However, recent innovations in advanced high-strength steels (AHSS) have been able to bridge that gap. To demonstrate the recent advancements made with AHSS, engineers designed the PBC-EV, or POSCO Body Concept-Electric Vehicle, using POSCO GIGA STEEL. The PBC-EV car body was able to achieve a 26.4% reduction in total weight when compared to cars of the same size without any sacrifices in safety or structural integrity. 

The Eco-friendly Life Cycle of AHSS

When measuring greenhouse emissions of cars, one must also look beyond the immediate impact of gasoline consumption and view the material more holistically through a life cycle assessment. The emissions costs related to the extraction and production of automobile materials can be high. However, technological advancements in steel production have been able to reduce CO2 emissions – helping to make it one of the most eco-friendly materials for car makers.

Based on its life cycle assessment, measuring carbon dioxide emissions from production to recycling, POSCO GIGA STEEL performs remarkably well as an eco-friendly material. Steel emits 2.0 to 2.5 kg of carbon emissions when producing 1 kg of material while aluminum emits 11 to 12.6 kg when producing the same amount. Even after production, cumulative greenhouse gas emissions of vehicles made with steel is 10% lower when looking at the full life cycle.

Lastly, steel remains the most recycled materials on the planet, and automobiles maintain a recycling rate of nearly 100 percent. Almost all steel products contain recycled steel as steel scrap is a necessary ingredient when producing new steel.

Advancements in AHSS have allowed the auto industry to move beyond the barriers that have held it back in the past. As consumers demand more fuel efficient driving options and as governments around the world impose more strict emissions standards, material advancements in steel will become more critical. It is the breakthroughs in steel technology like these that are helping to bring lightweight, fuel-efficient cars to market.

Throughout April and May, The Steel Wire is exploring trends in the auto industry and how POSCO’s innovations in automotive steel is leading the way toward lighter, stronger, and more affordable cars.

Volkswagen brought back its iconic Microbus in the form of a new electric, self-driving ID Buzz concept car. (Engadget)

The headlines from the Consumer Electronic Show (CES) were all about self-driving, electric, and connected cars. As these topics continued to be highlighted at NAIAS (see the new Volkswagen ID Buzz pictured above), there was also a focus on the importance of structural design.

Innovations in high-strength steel have allowed car makers to reduce the weight of vehicles without compromising safety. From large sedans to electric vehicles, advances in steel were spotted all throughout this year’s NAIAS with BMW’s new 5 Series and Ford’s new 2018 F-150 both showing off their lightweight aluminum and high-strength steel compounds that helped shed more than 100 kg from the BMW model.

The push to make vehicles lighter raises safety concerns. Lighter cars require lighter steel, and to make lighter steel there are typically other compromises that have to be made. POSCO, however, with its advanced high-strength automotive steel, has found the solution for automakers to make cars that are both safe and lightweight.

The new BMW 5 Series (left) and Ford F150 (right) made their debut at the North American International Auto Show. Both models used advanced high-strength steel to reduce weight and maintain safety. (NAIAS Image Archive)

POSCO’s Lightweight Auto Solutions Increase Safety

In 2016, POSCO became the first steelmaker to participate at NAIAS, displaying its advanced high-strength steel for automobiles, including its the PosM Steel and hot press forming steel (HPF). PosM Steel is five times stronger than other types of steel making it great for impact absorption and increased safety.

Providing a rapid solution upgrade for strengthened crash requirements, the safety of POSCO’s advanced materials has been certified by the Insurance Institute for Highway Safety (IIHS). In addition, the strength and crashworthiness of POSCO’s advanced steel solution received a score of 5 stars from USNCAP and ‘good’ safety ratings on the IIHS Moderate Overlap Front and Small Overlap Front tests. By reducing possible safety concerns with high strength body solutions, POSCO is able to contribute to the advancement of global auto manufacturers.

With steel being more important than ever in the auto industry, POSCO’s commitment to improving the strength and safety in its automotive steel has helped it maintain its position as a global industry leader. As Gregory Warden of GM said, “there is a whole new generation of steel coming” – and POSCO is helping to lead the way by creating new solutions that guarantee safety and fit the unique needs of its partners.

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