September AMP_Digital

FEATURE A D V A N C E D M A T E R I A L S & P R O C E S S E S | S E P T E M B E R 2 0 1 8 4 0 A utomotive heat treating has benefited from signifi- cant developments in recent years due to the need for high production and predictive process automation (PPA) to improve efficiency. Four major goals of automotive component heat treating include: • Reduce distortion in low mass transmission gears. • Choose materials that reduce vehicle weight to improve fossil fuel economy. • Reduce fossil fuel emissions like CO 2 , CO, and particulate matter. • Improve the range of hybrid and electric vehicles. Each heat treating and/or quenching process provides unique solutions for automobile designers and plant engi- neers. However, it is likely there is no single process or mate- rial that provides all the answers. There are advantages and disadvantages of quenching media options such as oil and press quenching and high pressure gas quenching (HPGQ), austempering (salt) for steel, austempering ductile iron (ADI), and the use of aluminumalloys versus other materials. This article discusses how OEMs and heat treaters can take advantage of particular hardening processes. Challenges facing auto designers include reducing emissions produced during acceleration to cruising speed and decreasing overall vehicle weight. Two methods for re- ducing weight include shrinking the overall unit size and adopting lighter (less dense) materials. Auto manufacturers in Europe and the U.S. each face their own unique challeng- es because consumers desire different car models, which affects the size and utility of product offerings. Thus, it is nec- essary to not only manufacture vehicles that meet govern- ment standards, but also produce vehicles that consumers will purchase. CONSUMER PURCHASING STATISTICS Per the Car Sales Statistics report on January 29, 2018, by Henk Bekker , in Europe the VWGolf was again the leading vehicle sold in 2017 with 445,206 units. In the U.S., SUVs and crossovers were segment leaders, with 3.53 million sold in 2017. Light trucks or pickups totaled 2,988,856 units. Overall, 17,134,700 vehicles of all kinds were sold the in the U.S. in 2017. For clarification, crossover SUVs are sport utility vehi- cles based on an automobile platform, while SUVs are truck- based. Considering that SUVs and light trucks on average weigh more than passenger cars, they require on average a higher proportion of weight reduction to meet their respec- tive efficiency criteria. Meeting the 2025 CAFE standards in the U.S. will be a challenge due to the weight of the vehicles: Americans love their trucks. With the deadline just around the corner, im- proving mileage by weight reduction alone seems impossi- PROS AND CONS OF VARIOUS AUTOMOTIVE MATERIALS AND HARDENING PROCESSES Automotive designers and heat treaters have many choices when it comes to the materials and processes that will meet their overall needs. Wallace (Jack) Titus AFC-Holcroft LLC, Wixom, Mich. Typical automotive parts made of austempered ductile iron. From left, turbo charger housing, exhaust manifold, and ring and pinion set. Courtesy of Wikimedia Commons/Panoha and zircotec.com . 8