South Korea’s largest steelmaker Posco is gaining industry attention for its unique ability to supply high tensile steel to vehicle manufacturers, providing them with lighter but more solid steel plates based on its cutting-edge technology.

The spotlight comes at a time when lightness has become a major trend recently in the automobile industry. Manufacturers of internal combustion engine vehicles have been putting out efforts to improve fuel efficiency and cut carbon dioxide emissions by reducing overall car body weight. Electric vehicle manufacturers also must make cars lighter to extend overall driving range with a single battery cell.

There have been several challenges, however, in reducing the car body weight as a lighter vehicle would mean higher risk when it comes to safety upon collision. Also, it would cost more to produce a lighter vehicle using high-end weight reduction materials. Aluminum is considered an alternative to steel plates as a weight reduction material but it triples the cost of a typical steel plate.

Amid the changing industry environment and rising demand for lighter car body, Posco has been distinguishing itself by offering automakers with a new steel plate solution based on self-developed technology - giga steel - which is high tensile steel that is lighter but stronger than existing steel plates.

Giga steel on high demand

There are three different types of automotive steel based on its tensile strength that measures material strength - low strength steel (LSS), high strength steel (HSS), and ultra-high strength steel (UHSS). The World Steel Association categorizes car plates into mild steel, conventional HSS and advanced HSS.

Among different types of automotive steel, giga steel is known as an ultra-high strength steel that is capable of withstanding tensile strength of one gigapascal (GPa) or 100 kilograms or more weight per square millimeter. Among the ultra-high strength family, there are extra ultra-high strength steel with double elongation that boasts both formability and strength, and also, ultra super high strength steel with triple elongation. Ultra super high strength steel is referred as the next-generation giga steel that generally requires highly sophisticated manufacturing skills as the control of components or production process are extremely complex compared to giga steel in general.

Posco’s Twinning-Induced Plasticity (TWIP) steel, world’s only mass-produced ultra super high strength steel, has three times or more formability compared to ordinary giga steel, allowing it to be deformed and applied to various car body parts. In particular, it has exceptional shock absorption ability that significantly raises safety when applied to a vehicle’s front and back bumper beams. The effect of Posco’s giga steel maximizes when it is applied to the core frame of a vehicle called body in white (BIW).

The car steel frame that Posco introduced at the North American International Auto Show in Detroit, the United States, in January, was 26.4 percent lighter than existing steel frame for compact cars, and also superior in terms of safety. Based on its own internal performance evaluation referring to the standards provided by the European New Car Assessment Programme (NCAP) and the Insurance Institute for Highway Safety (IIHS) - two car safety performance assessment institutions in Europe and North America - Posco’s car steel frame received the highest safety level of five stars and a “good” review.

Also, based on the evaluation result of its life cycle assessment that measures carbon dioxide emissions from production to recycling, the emissions of Posco’s car steel plates was about half of that of other internal combustion car bodies. It also emits 9 percent less carbon dioxide compared to an average electric vehicle body made with aluminum.

The features would likely bump up demand for giga steel in the automobile industry and make it eventually replace general steel plates.

According to Posco Research Institute (POSRI), demand for giga steel in a weight-reduced vehicle is expected to increase by an annual average of 24.3 percent, accounting for 69 percent of total steel plates in 2023, up from 37 percent in 2015.

Kwon Oh-joon, chairman and chief executive of Posco, said in a press conference in August that aluminum is considered a vehicle steel plate material with one third specific gravity level but giga steel is not only more price competitive than aluminum steel plates but also three times stronger while being similarly light.



Posco strengthens partnership with auto and auto parts manufacturers

The work of reducing vehicle weight requires collaborative efforts from all parties involved in car manufacturing - material producers, full vehicle assemblers, and auto component manufacturers.

Posco holds exhibitions and seminars regularly as part of efforts to enhance strategic partnership and expand technical and commercial ties with global automakers through innovative solution marketing.

On September 21, Posco held a Tech Day for Renault Samsung Motors Co. and similar events for Ssangyong Motor Co. and GM Korea Co. and appealed itself as a solution partner that works to maximize synergy with its customers rather than remain as a simple supplier of steel material. Domestic carmakers as well as leading auto components manufacturers took part in the technology exhibitions.

Posco also held a technology seminar that provides latest information on automakers’ needs and demands including steel application trends, examples of weight reduction technology and mass production application, giga steel technology, and ultra super high tense steel development plans. Posco has been able to present ideas on mid- to long-term partnership tasks for each automaker that reflect customer needs and also strengthen the basis for further technology partnership with the goal of promoting shared growth.

Under such technology partnerships, 71 percent of Ssangyong Motor’s body steel of Tivoli Air is made with Posco’s world premium high strength steel. Also, 18.5 percent of body steel for collision materials of Renault Samsung Motors’ SM6 is composed of ultra super high steel plate with 1.2 GPa or higher steel material including tailor welded blanks-hot press forming that has been mass produced for the first time in Korea, and also 1,180 CP. Posco obtained grade 1 in Korea New Car Assessment Program (KNCAP) and 5 stars in the European New Car Assessment Programme (ENCAP).

By Lee Yu-sup

[ⓒ Pulse by Maeil Business News Korea & mk.co.kr, All rights reserved]