EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

In the past decades, all possible strengthening mechanisms have been fully exploited to tailor the mechanical properties of steels. Nowadays, it is becoming difficult to move further and meet the continuously increasing properties requirements, as the physical limits have been almost reached in bulk metals. Multilayer metallic materials produced by roll-bonding can be a viable solution to combine “contradictory” properties (i.e. strength and energy absorption, abrasion resistance and toughness, etc.) in one single product. This paper describes the process parameters (surface preparation, interlayer coating, joining techniques and rolling schedule) to produce roll-bonded clad plates and strip. Three point bend testing proves that sound metallurgical bonding is obtained after hot-rolling at 1100 °C of steel multilayer-packs assembled by welding, whatever the steel chemistry and the rolling schedule applied. No abnormal inclusion density is found at layer interface. However, surface flatness is shown to be a fundamental requirement to build-up the packs prior to roll-bonding. ELC roll-bonded plates with different types of hard outside layers (pearlitic or, after accelerated cooling, martensitic) as well as hard plates with soft ELC outside layers were successfully produced at lab-scale. Countless others layers combinations can be developed for both strip and plates applications, free from thermodynamics and chemistry constraints.