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Life Cycle Assessment of Lightweight Materials for Automotive Applications
Published in Omar Faruk , Jimi Tjong , Mohini Sain, Lightweight and Sustainable Materials for Automotive Applications, 2017
Masoud Akhshik, Jimi Tjong, Mohini Sain
In order to reduce our emissions, we should use fewer resources and become more efficient; to do so there is a simple and common solution in the automotive and aviation industries and that is lightweighting. For every 10% weight that our car sheds we save up to 8% on fuel (Stans and Bos 2007; Van den Brink and Van Wee 1999). In case of aviation industries, releasing the CO2 in the atmosphere will cause more damage than a car because the altitude is higher and therefore it may be more important. The concept of lightweighting is really easy; it is literally replacing materials with higher density with the materials that have lower density but the same strength. For example, glass fiber has a density of about 2.5 g/cm3; therefore, whatever we put in our composite that has reinforcing fiber with lower density like natural fibers (1.4 g/cm3) we could see a lightweighting effect (Wambua et al. 2003). There is a well-known concept in science called the rebound effect, which can explain why with all the improvements in the internal combustion engines in terms of efficiency our car’s consumption has not been changed much. Rebound effect on the auto industries offsets the advantages (Hertwich 2005) on engine performance by increasing the curb weight of the vehicle. As you can see in Figure 13.2, global car weight increased during the past decades.
Current Packaging Trends and Related Technologies
Published in Chester L. Foy, David W. Pritchard, and Adjuvant Technology, 2018
Lightweighting is an example of a technology which addresses both environmental and business needs; less material is put into the environment, fewer resources are used, and shipping costs diminish for lower-weight products.
A parametric study on weld zone shape of resistance spot welded 22MnB5 steel
Published in Welding International, 2023
Oguz Tuncel, Hakan Aydin, Alisan Gonul
Automobile manufacturers are currently attempting to reduce vehicle emissions by making them lighter to comply with strict environmental regulations. The lightweighting process must be performed without affecting the vehicle’s rigidity or crash resistance by replacing heavy components (chassis, pillars, etc.) with lighter ones. The material properties of modern ultra-high-strength steels (UHSSs) guarantee low fuel consumption and fewer environmentally harmful gas emissions without reducing passenger safety [1,2]. The ultimate strength of UHSS exceeds 800 MPa. Among these UHSSs, press-hardened steel (PHS) has an exceedingly high tensile strength (>1500 MPa). It is commonly employed in anti-collision structural components of automobile bodywork, such as A- and B-pillars, beams, and other body structural components [3]. Despite these advantages, UHSSs have disadvantages, such as limited formability, which causes breakage and excessive spring back during room-temperature forming. A hot stamping procedure has been developed to improve the strength and eliminate the existing problem using boron manganese alloy steel (22MnB5). While the tensile strength of 22MnB5 steel is approximately 600 MPa and its microstructure is ferritic-perlitic, they transform into the martensitic structure through a hot forming and cooling process at cooling rates above the critical cooling rate, resulting in a tensile strength greater than 1500 MPa [4,5]. These steels, also known as hot-formed boron steels, achieve high strength and hardness values as a result of quick cooling after forming due to the presence of Mn and B. In addition, hot-formed boron steels coated with Al-Si to avoid high-temperature oxidation and air corrosion [6,7].
Material characterisation for strength and formability limits of DP 1180 sheet
Published in Canadian Metallurgical Quarterly, 2022
One way to reduce fuel consumption and emissions is to reduce vehicle weight. On the other hand, the lightweighting solutions negatively affect safety. Advanced and ultra high strength steels (AHSS and UHSS) are utilised in increasing volumes in the automotive industry to solve both problems simultaneously. Dual phase (DP) steels are among the first developed advanced and ultra high strength steel families. The name was given in the mid-70s because of the microstructure [3]. The microstructure consists of mostly ferrite and martensite. Bainite and retained austenite can be seen in small volumes depending on the steel-making process. Ferrite is the soft phase and martensite is the hard phase. As the martensite content increases, the strength increases, and ductility decreases [4–6]. The microstructure of DP steels is very much different from the microstructure of conventional high strength steels like high strength low alloy (HSLA) steels. HSLA steels have a single-phase microstructure which consists of ferrite. Therefore, mechanical properties like hardness, flow curve, anisotropy, forming limit curve, and hole expansion ratio are different from HSLA grades [7,8]. DP steels have a higher ultimate tensile strength in comparison to HSLA with the same yield strength. Thus, yield strength to ultimate tensile strength ratio is lower for DP steels and they show larger springback. DP steels do not exhibit yield point elongation. Strength increases because of the baking process in painting. The strain hardening exponent (n) of DP steels is higher than HSLA steels during the initial stages of forming. Therefore they exhibit more uniform strain distribution which can delay the formation of fracture [7–11]. Mechanical properties vary in terms of grain refinement, alloying elements, and the ratio between ferrite and martensite contents. Researchers from the steel industry [12–16] and academia [17–19] have been trying to reach higher strength and/or higher total elongation. Sriram et al. [16] reported that mechanical properties improved with aluminium addition. Terada et al. [17] investigated the effect of two kinds of heat treatment methods on the formation of martensite. One method results in linked martensites and the other method leads to individual martensites. DP steel with linked martensites showed better elongation. Ghaemifar and Mirzadeh [18] studied the effects of repetitive intercritical annealing on the strength and elongation of dual phase steels. Dutta et al. [19] analysed the influence of alloys and process parameters on the mechanical properties using neural network and genetic algorithm. Hu et al. [20] evaluated the effect of the tempering process on the formability of DP 980 by running tensile and hole expansion tests. Poulin et al. [21] found that total elongation and strength of DP 1180 increased when the sheet was bent and pulled simultaneously compared to just pulling. Similar results were obtained for DP 590, DP 780 and DP 980 [22].