Effect of rolling conditions on ferrite refinement of low-carbon steel
Refinement of the ferrite grains provides a promising approach to simultaneously improving both the strength and the toughness of steels. Among recent techniques to obtain ultrafine ferrite, dynamic strain induced transformation (DSIT) is used. This type of treatment is sensitive to steel composition, deformation temperature, the prior austenite grain size, strain and cooling rate. This work is aiming to improve the mechanical properties of steels using ferrite grain refining through trials on industrial scale using a compact strip production plant (CSP) with hot strip mill (HSM) containing six stands F1-F6 in EZDK Steel Company. The chemical composition of the trials was C (~0.046), Si (0.073) Mn (0.50) and Ti (0.008). The effect of final deformation temperature of 750, 775, 800 and 815°C on the microstructure and mechanical properties was studied. In addition the effect of strain rate variation at the final two rolling stands was correlated with the ferrite refining mechanisms. The ferrite grain size attained after refining varies from 10 μm to be 6 μm. Yield and tensile strength increased slightly through changing deformation temperature, with the advantage of keeping almost the original high ductility. Toughness of the processed steel increased with ferrite grain refining.
Deformation enhanced transformation and dynamic recrystallization of ferrite in a low carbon steel during multipass hot deformation
Abstract Multipass hot deformation with an industry-acceptable pass reduction has been investigated by hot compression. A fine ferrite grain size can be achieved by carefully controlling the interaction of the deformation-enhanced transformation and dynamic recrystallization of ferrite. By the development of a ferrite grain size of 3–5 μm, the yield strength of Q235 grade plain carbon steel can be doubled, without significant loss of ductility, compared with material produced by conventional processing.
Law in a law-governed union (Recht in einer Rechtsunion) : the Court of Justice of the European Union and the free law doctrine
The Court of Justice of the European Union characterizes the Union as a Rechtsunion: a law-governed union. The conception of “the law” in Article 19 paragraph 1 of the Treaty on European Union transcends the Treaties, according to the Vice-President of the Court of Justice, Koen Lenaerts. This thesis demonstrates with reference to the work of Georg Jellinek that the Union is a non-sovereign state and, with reference to the work of Eugen Ehrlich in particular, that the state-based perception of law is a misperception. Not all production of law is reserved to the state and not all law is state-recognized law. There is extra-state law. It has been alleged that the Court of Justice of the European Union has had “a free law attitude”. The author discusses the free law doctrine developed at the beginning of the twentieth century and has made literal translations of writings in German, French and Italian by the main representatives of the free law movement. The free law doctrine provides a descriptive framework for the case-law of courts. The author describes the creation by the Court of Justice of four constitutional principles of Union law through its case-law. He concludes that every court is, to quote Hermann Kantorowicz, praeter legem law-creatively active and has, in that sense, a free law attitude. The decisions of judges are often volitional decisions. How the law will be applied should be predictable but volitional decisions, because they are unpredictable, are inconsistent with the principle of legal certainty. In the Union and its member states the judiciary and not the statute or “the law” is pre-eminent. The author suggests how the concept of law should be defined in a material Rechtsunion. He argues that societal legal norms could be provided with an appropriate position consistent with the principle of legal certainty by making the validity of a societal legal norm contingent on its material lawfulness.