12th International Conference on Zinc & Zinc Alloy Coated Steel Sheet - GALVATECH 2021

Automotive industry requirements for steels capable of enabling increasingly fuel-efficient vehicles continue to drive process technology developments for North American hot-dip and electro-galvanizing lines. Third-generation zinc and zinc alloy-coated grades have reached commercialization; higher-capability grades continue to be developed. Zinc-coated hot press forming grades have reached commercialization, tailor-processed hot press formed grades permit increasingly efficient use of steel in automobiles. A key barrier to adoption of advanced zinc-coated steels are incidences of liquid metal embrittlement (LME) that is associated in many cases with higher levels of steel retained austenite or silicon alloying and ameliorative practices are under development. Quality and productivity benchmarks also continue to be pushed to ever-higher levels. Dual phase and multi-phase grades with expanded combinations of formability and strength continue to be developed. Such steel grades should satisfy automaker requirements and ensure the dominance of steel-based vehicle manufacturing for many years to come. The processing of these steels creates challenges for steel suppliers, and the approaches being taken to meet these challenges are described. These include reactive wetting, IR pyrometry during heat treating of advanced high strength steels (AHSS), hydrogen-induced delayed cracking and cold rolling harder substrates. A new census of North American production coating lines is provided. Challenges for the future include further improved productivity, quality and process efficiency, and flexibility in line scheduling to minimize costs.