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Joule Heating Forming System
- Project Overview
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Project name Joule heating forming system-applied super-high strength car body parts (door parts) commercialization & development Joule heating forming system-applied super-high strength car body parts (door parts) commercialization & development Korea Automotive Technology Institute Participating institutions Asan Factory of Kyungki Industrial Co., Ltd
- Automotive regulation trends
- To tighten regulations on greenhouse gases and fuel efficiency for each country
- Domestic: Required to reduce CO2 emission to 97g/km and improve fuel efficiency to 24.3km/ℓ by 2020.
- If not accomplished, pay penalty (Unaccomplished CO2 emission (g) x 10,000 won, unaccomplished fuel efficiency (1km/l) x 82,000 won))
- Overseas: Required to reduce CO2 emission to 91g/km for Europe, 100g/km for Japan, 113g/km for USA, and 110g/km for China by 2020 (In case of USA, improve fuel efficiency to 23.1km/l by 2025)
- If not accomplished, pay penalty (As for Europe, unaccomplished CO2 emission (g) x 95 Euros, since 2019)/ (As for USA, unaccomplished fuel efficiency (1km/l) x 130$)
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- Increased demand on the automotive weight lightening
- The necessity of automotive weight lightening has increased owing to restrictions on greenhouse gases and regulations on fuel efficiency.
- The automotive weight has increased by an average of 15kg every year owing to increase of all kinds of convenience/ safety devices.
- If automotive weight decreases 100kg, averagely 1.6 million liters of fuel and 2 billion kg of greenhouse gases can be reduced per day.
- If automotive weight decreases by 10%, the fuel efficiency increases approximately 3.8% and the emission of CO2 and Nox decreases by 4.5% and 8.8% respectively.
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Trends of weight in small and medium-sized vehicles (EU Automobile Association)
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Trends of fuel efficiency according to vehicle weight (Automobile Committee of Japan AI Association)
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- Strengthen regulations on collision safety
- Strengthen regulations on collision safety to ensure passengers’ safety
- A multiple kinds of vehicles were rated “poor” in the recent 25% offset frontal crash test, North America.
- The demand on high-strength door and side parts has increased to reduce the damage of heads and chests for passengers on a broadside collision.
- The application of 1GPa or higher class super high-strength steel sheet or lightweight parts tends to increase greatly.
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- Trends of domestic and overseas application of super high-strength parts
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Trends of application of super high-strength and lightweight parts to overseas complete vehicles
590-980MPa : 13.0%
1000-1310MPa : 16.0% -
Trends of application of super high-strength and lightweight parts to domestic complete vehicles
620-1280MPa : 6.1%
980-1160MPa : 3.1%
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- The percentage of Gpa-class structural steel application is expected to increase to 40% by 2020.
- It is necessary to secure process technology for developing super high-strength lightweight car parts.
- Domestic and overseas trends of super high-strength parts development
- Improvement of super high tensile strength by phase transformation
- Improvement of super high tensile strength by phase transformation
- Conventional hot stamping forming technique
- A heating furnace is as long as 40m and requires high investment cost.
- As it takes 10 minutes to increase temperature to 900℃, it reduces productivity and increases fueling cost.
→ Medium or larger companies only afford to make an investment.
Development of electrically assisted forming technology
- Electrically-assisted forming technology under development in some foreign countries is intended to improve formability by electricity without temperature rise. This technology is based upon the principle in which electrons move between grain boundaries in metal materials and decrease flow stress temporarily during transformation.
- ? As this technology can improve the formability of magnesium and aluminum within limits, it has limitations in applying to commercial application of super high-strength parts.
- Summary of development technology
- Development of Joule heating forming technology-applied super high-strength door parts
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- Development of rapidly tailored heating temperature control technology based upon Joule heating (within 0.2 seconds)
- Commercialization and development of Joule heating forming system and forming process
- Commercialization and development of tailored high-safety, light-weight and high-quality door modules
- Lay a foundation to commercialize environment-friendly manufacturing process by increasing energy efficiency
- Secure new forming production-base technology of super high-strength parts for small and medium-sized businesses to ensure reduction in investment cost and production space
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- Differentiation of technology development
- Joule heating forming technology and door modules
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- Rapid electric resistance heating reduces heating time by 90% and cycle time by 25 seconds.
- Reduces surface oxidization rates by 90% and controls strength by application areas → tailored super high tensile strength lightweight door modules
- Environment-friendly manufacturing process by increasing energy efficiency
- Reduces investment cost in equipment by 80% and production space by 5 meters; makes it possible to form super high tensile-strength parts for small and medium-sized businesses
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Conventional hot-stamping forming technology
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Developed Joule heating forming technology
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- Developed Joule heating forming technology
- Development of rapid Joule heating forming system
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- Analysis and deduction of Joule heating core factors (Electric current, voltage, heating time, etc.)
- Analysis of correlation among heating temperature, cooling speeds, phase transformation and parts strength
- Design and production of rapid heating direct forming system
- Design and production of Joule heating system to increase temperature rapidly and cooling efficiency
Deduction and analysis of core forming factors
Joule heating system/ mold design
Production of Joule heating forming system
Development of rapid Joule heating forming process
- Conduct heat transfer analysis according to the grip of Joule heating area.
- Construct high-temperature property data according to temperature and strain rates
- Develop hot forming analysis technology in consideration of phase transformation according to process conditions
- Analyze product quality according to process conditions (Electric current, voltage, and time)
Development of heat transfer analysis technology
Development of forming analysis technology in consideration of phase transformation
Quality analysis according to process conditions
Development of super high-strength door module prototypes, evaluation and verification
- Manufacture of Joule heating forming technology-applied door impact beam
- Static strength analysis and test evaluation of impact beams
- Manufacture of jigs for door module assembly and door modules
- Final evaluation and verification of door module static strength and impact strength
Static strength analysis and evaluation of door impact beams
Impact analysis and manufacture of door modules
Final verification of impact strength of door modules
- Current situation of supervising institutions’ research capability
- Joint research utilizing the results of research on Joule heating forming technology
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Patent application: Forming methods of electric current flow system for jig equipment and automobile plate.
- Expected effects of technology development
- Secure the manufacturing technology of 1.5GPa-class super high-strength lightweight doors
- Build infrastructure to manufacture Joule heating-applied 1.5GPa-class door parts
- Organize new materials creation network by developing super high-strength car body parts
- Secure technology by utilizing human network and raise professional personnel
- Secure parts manufacturing technology according to the increased demand on super high-strength lightweight parts and improve national competitiveness
